Category Archives: News

The Problem With Jane Goodall’s “Expert” Opinion

On September 7, 2017, Dr. Jane Goodall wrote a scathing letter to Dr. Scott Gottlieb, Commissioner of the U.S. Food & Drug Administration (FDA) denouncing what she called the “cruel and unnecessary nicotine addiction experiments on monkeys” occurring there. The letter, which relies on the repeated use of opinion versus fact-based arguments by Goodall, is not just problematic, it’s downright dangerous.

This is not Goodall’s first time lending her name to various efforts by animal rights activists opposed to federally-supported biomedical and behavioral research, despite her lack of expertise or relevant credentials. Goodall has often partnered with animal rights groups to attack life-saving science. In March 2016, she supported a campaign by the Animal Justice Project to stop preclinical trials of a new malaria vaccine. In September 2016, Goodall joined Cruelty Free International (CFI) to co-author a letter attacking the use of animals in neuroscience research (to which a counter-letter, signed by 400 prominent experts in the field, was published). In February 2017, Goodall worked with For Life on Earth to call out Prof. Roger Lemon, a notable Professor of Neurophysiology, to criticize his comparative work with both humans and non-human primates.

Squirrel monkey. Source: Wikimedia Commons.

As detailed here, her most recent letter to the FDA, in partnership with The White Coat Waste (WCW) Project, a conservative-leaning animal rights organization devoted to the elimination of animal research, relies on the repeated use of opinion rather than empirical observations or rigorous study to arrive at sweeping – and dangerous – conclusions.  

The problems

We’ll tackle this letter in particular, though past letters signed by Goodall and other notable figures like David Attenborough, are similarly flawed and should be similarly scrutinized.

  • No relevant credentials or expertise: This one bears repeating. Although this should be obvious, to many it is not. Though she possesses a PhD and is described as an expert on chimpanzees, Goodall’s “expertise” ends there. She does not possess an advanced degree pertinent to the field of addiction research, and moreover she has never conducted research in a biomedical research facility. Thus, her first-hand knowledge of the methodology and oversight in these types of studies is questionable at best. Would you consult a cardiologist for questions about your car’s transmission?  Or, conversely, consult an auto mechanic about your open heart surgery? In fact, Dr. Goodall appears to recognize this. For example, in her video targeting Prof. Roger Lemon, midway through the video Goodall notes: “I don’t have the scientific medical knowledge to take issue with Professor Lemon” before going on to demand he debate pseudoscientist, Dr. Ray Greek. The problem here is that the weight given to Goodall’s opinion is directly related to impressions of her expertise and credentials. This issue of ethics of expertise is an important one. Goodall herself may not be directly claiming to be a neuroscientist, or an addiction researcher, but one of the reasons that her opinion may be thought valuable in these campaigns is because she is a scientist. As as scientist, it is worth considering whether Goodall should be upfront about her lack of expertise in the topic at hand. In fact, Goodall’s conclusion that the research is “unnecessary” and that “the results of smoking are well-known in humans” are opinions, rather than statements based in evidence and expert analysis.

    “I don’t have the scientific
    medical knowledge…”
    – Jane Goodall

  • “I have been told that…”: This should immediately set off alarm bells to anyone reading Goodall’s letter. Forget what comes after that – who has told her what she describes? As we have noted in the past, it’s crucial to know the starting assumptions of those engaging in a conversation, and the assumptions must be spelled out. In this case, it is no secret that Goodall has worked with The White Coat Waste (WCW) Project, a conservative-leaning animal rights organization devoted to the elimination of animal research (this starting position itself is dangerous, as described below). The WCW’s site itself states, “On the heels of WCW’s new lawsuit against the Food and Drug Administration (FDA)…Dr. Jane Goodall has joined WCW’s campaign to expose and end this wasteful project.” Put simply: Goodall appears to rely only on information provided to her by animal rights groups to make the case in her letter.
  • Factual inaccuracies: Probably because she appears to rely on the distorted information from WCW, Goodall’s letter is full of multiple inaccurate statements. One example is when she writes, “Not only is it extremely cruel to restrain the monkeys.”  In reality, empirical evidence—that is data – show that restraint devices used in such studies do not cause severe stress to the animals, because they are slowly trained to be familiar with and calmly enter and remain in the restraint devices. Despite her scientific background—which should result in knowing that evidence and citations matter—Goodall cites no evidence for her claim that restraint is “extremely cruel.”
  • Sweeping assumptions: At least two glaring assumptions stand out in Goodall’s brief letter.
    1) Goodall writes, “To continue performing nicotine experiments on monkeys when the results of smoking are well-known in humans – whose smoking habits can still be studied directly – is shameful.” There are several problems with this statement. The first is that Goodall assumes that the monkey studies examining the neurobiology and physiology of nicotine addiction is the same thing as studying smoking habits in humans. Someone with expertise in this field should know these are false equivalencies. The only other plausible explanation is that she is choosing to ignore the fact that these two are not the same thing. The FDA describes on its webpage that nicotine research will inform about the toxicity of tobacco products as they continue to change by manufacturers, about how changes in tobacco product characteristics (e.g., aerosolized chemicals, often including nicotine, found in e-cigarettes) impact addiction, and about the changes in cell function/physiology after tobacco exposure. These types of findings are not readily available from studying humans’ smoking habits. 2) Near the end of her letter, Goodall writes, “I’m sure that most Americans would be horrified to learn that their tax dollars are paying for this abuse.” Again, Goodall makes major assumptions without citing any sources of data. We can just as confidently say that we’re sure most Americans would be glad to know their tax dollars are being used in highly-regulated research studies that address the health of current and future generations.

The dangers

  • Calls for de-funding life-saving research: The most recent nicotine delivery methods, e-cigarettes, have not yet been well studied for their health effects, yet they represent a major public health concern. We do not yet know all the ways in which nicotine in e-cigarettes affects the brain. Studies such as those conducted by the FDA in animals, including monkeys, will teach us how these new delivery methods affect the brain and body, which will in turn lead to recommendations for regulation of these products and potential treatments for addiction. Despite these life-saving benefits, Goodall and WCW call for an end to this line of research in their letter. This explicit threat should ring alarm bells for any citizen concerned about public health. But this is not the first time animal research opponents have called for an end to beneficial research. Just a week ago, the Secretary of the Department of Veterans Affairs (VA), Dr. David Shulkin, had to make a plea to the United States Senate to not end life-saving canine research after a campaign by – you guessed it – WCW called for an end to this line of work. Think about that. The VA Secretary had to lobby the U.S. Senate to save a life-saving research program for veterans.

  • Threats to the advancement of scientific knowledge: As if threats to life-saving research weren’t enough, animal rights campaigns that rely on “experts” like Goodall are also threatening to end – or have already ended – scientific programs geared toward broadening and enhancing society’s basic knowledge of the way the world works, from the toxic effects of vapors in e-cigarettes to the safety of new vaccines to the communication between neurons to mechanisms of stress resilience to…the list goes on. This type of basic knowledge is crucial before life-saving treatments can be developed. This implicit threat should ring alarm bells for any citizen, period.

The Fact Check: PETA vs. Christine Lattin

A systematic evaluation of PETA’s claims about Dr. Christine Lattin’s research highlights a lack of context, misrepresentation of her work, and – in some cases – statements that are just not factually accurate. Again, PETA demonstrates to the world why we should not take such claims at face value.

PETA’s campaign against Dr. Christine Lattin, an early career researcher at Yale University, began in May 2017. At first blush, this seemed like the usual nonsense that PETA often gets up to: sensational claims and some selective reporting about the issue at hand – usually in an effort to get the maximum emotive response regardless of the truth or of the consequences (see for e.g., here, here, here, here).

A quick search (see Dr. Lattin’s website and Twitter) reveals a researcher that is open and transparent about her research, critical about the limits of interpreting her research, and one willing to stand up to these allegations without fear – a sign of true conviction about one’s work. Recently, PETA upped the ante and posted a long diatribe claiming that Dr. Lattin, who was defending herself and her research via Twitter, was presenting an alternate version of the facts.

We decided to evaluate PETA’s claims against Dr. Lattin in order to provide a public view of the facts and context that are relevant to considering PETA’s statements. We are not claiming an absence of potential bias, nor should others. PETA also has a particular interest in the topic, as they clearly state their view opposing all use of animals by humans (for research, but also food, clothing, and entertainment). As well, many of us that are affiliated with Speaking of Research study animals in our own research, and therefore have a vested interest in this topic. With these starting assumptions in mind let’s jump in.

Sub-topics:

VALUE OF THE WORK IN TERMS OF APPLICABILITY TO OTHER SPECIES?

Lattin claim (paraphrased by PETA): “[I]f my research wasn’t [sic] applicable to humans or any other species, it wouldn’t get approved, funded or published.” (Twitter, August 3, 2017)

PETA response: Applicability to humans or other species is not a condition for approval, funding, or publication of research. Indeed, the results of many of the most abusive experiments using animals are not relevant to humans and are driven only by curiosity. For instance, the National Institutes of Health (NIH) funded a series of infamous stress experiments [by Harry Harlow, emphasis added] in which infant monkeys were stuffed into tiny cages and then terrorized with loud noises. A horrific variation on this involved drugging mother monkeys, taping over their nipples, and then observing how their frightened babies frantically tried to wake them up. The experimenter responsible for this cruelty admitted publicly that his results were not relevant to human mental illness. Yet NIH saw fit to fund these experiments for more than 30 years with a total of more than $35 million.

Applicability to humans or other species is not a condition for approval, funding, or publication of research. That is a strength of science – a feature, not a bug, because the foundation of scientific discoveries and advances depend on basic research. It would be disingenuous to stop there though. Where research can potentially cause harm or distress there generally needs to be a clear justification of applicability, for example, either to the species being studied or to other animals, in order for such work to be conducted. Some of Dr. Lattin’s research involves a degree of stress, and will therefore have been subject to an analysis that weighs risks to the animals with consideration of scientific objectives and potential benefits from the research.

Indeed, if one were to read Dr. Lattin’s publications, which are posted freely on her website, one would see that her research is not driven by simple curiosity but clearly states the applicability of her research to other species of passerine birds. And, as an example of selective reporting, PETA fails to post/address the very next comment that Dr. Lattin’s posts on her Twitter feed where she provides an example of the applicability of her work to other species.

We have previously addressed the one sided argument against the NIH funded research of Harry Harlow. We also note that Harlow died over 35 years ago. Harlow’s work, and that of his contemporary colleagues, is one used in arguments by those opposed to animal research.  As we state in a previous article:

“Contrary to prevailing views in the 1950s and before, the Harlows’ studies of infant monkeys definitively demonstrated that mother-infant bonds and physical contact—not just provision of food—are fundamentally important to normal behavioral and biological development. Those studies provided an enduring empirical foundation for decades of subsequent work that shed new light on the interplay between childhood experiences, genes, and biology in shaping vulnerability, resilience, and recovery in lifespan health.”

We, and others – including NIH and leading scientific organizations have addressed and supported the contemporary research to which PETA refers (e.g., NIH statement, APA statement, ASP statement).

IS RESEARCH WITH WILD BIRDS REGULATED IN THE USA? YES.

Lattin claim (paraphrased by PETA): “Also: there is a TON of oversight on all animal research (mine included). It’s not illicit or secret.” (Twitter, August 3, 2017)

PETA response: Lots of paperwork does not equal protection for animals. The systems of oversight in laboratories are weighted in favor of the experimenters and often fail the animals they are designed to protect. The only law that offers any sort of protection for animals in laboratories deals primarily with housekeeping issues and excludes birds, mice, rats, reptiles, amphibians, and animals used in agricultural experiments. No experiment is illegal.

Experimenters can deliberately inflict psychological suffering and pain with the flimsiest of justifications and still receive approval by oversight committees. As a result, many experiments that are wasteful and irrelevant and cause significant suffering are approved. Just two of many recent examples include experiments on dogs with canine muscular dystrophy that have failed to lead to any effective treatments and others in which hamsters were given cocaine and forced to fight.

PETA lumps a lot of little things together (a gish gallop tactic), perhaps in the hope that by doing so, the perception of similarity/applicability is achieved. The first criticism states that the Animal Welfare Act in the USA does not cover rats, mice, and non-mammalian vertebrates. However, this does not mean that these animals are not without protection or consideration, as we have previously explained. In fact, these animals receive oversight in numerous ways. Among them, federal law mandates compliance with standards, provides external oversight and mechanisms for public transparency of federally-funded research with rats, mice, and birds.  Further, accreditation by AAALAC requires compliance with standards. Finally, the research is subject to IACUC approval and oversight.

Moreover, the wild birds that Lattin studies are covered under the Animal Welfare Act, as explained by Ellen Paul, executive director of the Ornithological Council. Additionally, some of Dr. Lattin’s work actually informs standards for the keeping of wild birds in captivity and for example, include the consequences of captivity across time on the behavior and physiology of wild birds.

“The Animal Welfare Act covers all warm-blooded animals. In the past, the regulations excluded rats, mice, and birds. After litigation, the USDA agreed to include these taxa but a Farm Bill amendment excluded “purpose-bred” rats, mice, and birds.”

As Dr. Lattin’s birds are wild caught, and not purpose bred, they remain covered by the Animal Welfare Act.

The second criticism – that research can involve significant suffering and pain on a whim is not supported by the available evidence. Only approximately 3% of all approved experiments are rated as severe, and cause significant suffering (inferred from the severity ratings of countries that provide them and categorized in the USA as “E”). Moreover, and as mentioned previously, the risk benefit analysis in the USA, and the Harm-Benefit analysis in Europe and Switzerland, all require that any harms experienced by the animals are weighed with respect to the scientific objectives, the potential benefit of performing the experiment, or both. So, once again, PETA’s statements are demonstrably false.

Dr. Christine Lattin checks the tag on a bird to be released as part of her research.

WHAT DOES THE FACT-CHECK OF PETA’S SELECTIVE EVALUATION OF DR. LATTIN’S RESEARCH REVEAL?

PETA continues: Like these, Lattin’s studies have not led to any useful real-world applications, hinge on the deliberate infliction of pain and suffering, and require the death of the birds used. Here’s a sampling of what birds have endured in her experiments with “oversight”:

  1. Experimenters subjected birds to terrifying stressors, including rattling their cages, rolling them on a cart so that they could not perch, and physically restraining them, for 30 minutes four times per day at random intervals.[1]

What are these procedures that PETA calls “terrifying stressors?” They are part of a well-established approach to studying stress, called chronic mild stress, in biomedical research. Paul Willner, was the first to describe and subsequently validate this approach, and in a recent open access methodological review highlights the translational value of this model.

“Now 30 years old, the chronic mild stress (CMS) model of depression has been used in >1300 published studies, with a year-on-year increase rising to >200 papers in 2015. Data from a survey of users show that while a variety of names are in use (chronic mild/unpredictable/varied stress), these describe essentially the same procedure. This paper provides an update on the validity and reliability of the CMS model, and reviews recent data on the neurobiological basis of CMS effects and the mechanisms of antidepressant action: the volume of this research may be unique in providing a comprehensive account of antidepressant action within a single model. Also discussed is the use of CMS in drug discovery, with particular reference to hippocampal and extra-hippocampal targets. The high translational potential of the CMS model means that the neurobiological mechanisms described may be of particular relevance to human depression and mechanisms of clinical antidepressant action.

Dr. Lattin also addresses this in her paper but this rationale, justification, and context are not fully evident in PETA’s consideration. For example, in the paper that PETA references, Dr. Lattin first points out why studying chronic stress is important, and in particular, relevant to our understanding of the bird itself.

“…diagnosing chronic stress is not simple – the effects of presumed cases of chronic stress vary by species, stress paradigm, life history stage and other factors…”

“…knowing whether animals are successfully coping with stressors or suffering deleterious effects from an overactive HPA axis can be crucial for diagnosing the health of an individual animal.”

Dr. Lattin then highlights why she used these particular mild stressors.

The stressors usedhave all been shown individually to significantly increase CORT titers…” [note CORT refers to the stress hormone cortisol]

Yet, none of these considerations are highlighted by PETA, even though they are clearly and logically presented in Dr. Lattin’s publication.

  1. PETA: “One bird died during the administration of anesthesia prior to euthanasia.[2]

This is factually incorrect: “One male from the chronic stress recovery group died prematurely under anesthesia during perfusions” NOT during anesthesia – meaning that the animal was successfully rendered unconscious. Because Dr. Lattin’s wild caught birds are a heterogeneous population, i.e., they may vary in age, body status, immune composition etc., there will be individual differences in the way they respond to the anesthetic and sometimes, may do so in an unpredictable way — even when the recommended dosing is followed. Moreover it highlights why we need more research on wild caught birds – so that we may better understand why these individual differences exist and to accommodate such predictions into existing anesthesia protocols. Finally, because this bird was rendered unconscious at the time of death – it experienced no pain at its time of death.

  1. PETA: “Twenty-six feathers at a time were plucked from birds without pain management.[3] Plucking large numbers of feathers can cause bleeding, skin irritation, discomfort, and difficulty with thermoregulation.

In this paper, Dr. Lattin plucks feather from these birds to induce molting. Here, she was interested in validating a less invasive and integrated measure of a birds’ stress response. Note that this is first line of text in the paper.

“The newly described technique of extracting corticosterone (CORT) from bird feathers may serve as a less invasive, more integrated measure of a bird’s stress response.”

In the paper, Dr. Lattin states that she followed the method of Strochlic and colleagues. Of relevance here is that this procedure is performed under anesthesia – meaning that the animal was unconscious during the procedure.

“Starlings were briefly anesthetized with halothane, an inhalable anesthetic, administered in a nose cone and feathers were plucked by hand…”

It is not standard veterinary practice to administer analgesics following this procedure as it is not considered to be painful after the initial plucking; again note that this procedure was performed under general anesthesia. It is unlikely that this procedure causes bleeding, or the administration of analgesia, topical or otherwise would have been prescribed. Moreover, it is standard procedure to maintain birds at temperatures that may cause thermoregulatory distress.

These arguments presented by PETA therefore seem to be strawmen, meant to evoke an emotive response but once again are not supported by the available facts.

  1. PETA: “Capsules were surgically implanted under birds’ skin to administer drugs and then removed without pain medication.[4]

In the paper, Dr. Lattin again states that she followed the method of Strochlic and colleagues. Of relevance here is that this procedure is, again, performed under anesthesia – meaning that the animal was unconscious during the procedure. Please see the preceding the point for further discussion about the necessity of analgesia.

“All birds were anesthetized with metafane and implants were inserted subcutaneously between the shoulder blades. Silk sutures closed the incisions.”

  1. PETA: “Birds were used for multiple experiments and in some cases kept in captivity for several months before being killed.[5], [6], [7]

The same animals were studied as part of a single research program that addresses multiple questions. Studying the fewest animals possible often means the same animals are used within multiple studies. Re-using animals for experiments is consistent with the 3R principle of reduction, and minimizes the overall stress experienced by removing the need to capture more wild birds. Again, Dr. Lattin is transparent about this in her publication.

“As part of another study published previously (Lattin et al., 2014), we took body mass measurements and blood samples from all birds immediately before the onset of feeding and 2 and 4 weeks into the feeding experiment. The results of this sampling have been described in detail elsewhere (Lattin et al., 2014).”

  1. PETA: “Two birds died of “unknown causes” after two weeks of captivity.[8]

This is transparently stated in the paper. One should not confuse the use of the term “unknown causes” with the implication of wrongdoing.

  1. PETA: “Birds lost 8 percent of their bodyweight and heart mass, and their muscle density decreased during the stress of captivity and repeated experimentation.[9]

This is precisely some of the information Dr. Lattin seeks to discover. In this research, Dr. Lattin investigates the long-term effects of captivity on wild birds by measuring behavior and physiology. From this research she determines, “From a conservation perspective, this study … suggests that time in captivity should be minimized when birds will be reintroduced back to the wild.” Therefore, the loss of 8 percent bodyweight etc., is evidence for future researchers to reduce the time birds spend in captivity before being reintroduced back into the wild. It is not evidence to justify not doing the research in the first place; it is evidence that such research needs to be refined – which is exactly how refinements in animal care progresses and is reflected in the 3R perspective of refinement.

  1. PETA: “Birds exhibited behavior that indicated stress and anxiety, such as beak wiping and feather ruffling.[10]

Another glaring example of where context matters. Dr. Lattin investigates in this paper whether “experimentally reducing stress-induced corticosterone [i.e., stress hormones, emphasis added] may mitigate some captivity-induced behavioral changes”. And, indeed, she does find a decrease in beak wiping but not feather ruffling in animals treated with a drug to reduce stress. So contrary to PETA’s claims, Dr. Lattin shows that one of the detrimental consequences of captivity, increased beak-wiping, can be reduced in birds brought to the laboratory for various purposes, including conservation – a further case of refinement.

  1. PETA: “Wounds were inflicted on birds’ legs without pain medication.[11]

In Dr. Lattin’s paper it clearly states, “Prior to wounding we anesthetized birds using isoflurane.” What that means is that the birds are unconscious during the procedure and therefore were not able to perceive pain. The Ornithological Council’s guide states:

“An anesthetic is an agent that produces analgesia (loss of pain sensation) and, in the case of general anesthetics, immobilization and loss of consciousness so that the individual is unresponsive to stimulation. Anesthesia ideally minimizes stress and eliminates pain during a research procedure.”

  1. PETA: “Some birds were so distressed that they lost 11 percent of their bodyweight within five days of capture.[12]

Dr. Lattin has previously shown that decreased body weight is a consequence of captivity and in the present paper she uses captivity as a model for chronic mild stress (see point 1 and 7). She also notes in her paper, “After 5 days of captivity, house sparrows lost 11% of initial body mass, although birds lost more weight during molt and early winter”. This indicates, that the weight loss is within the normal range for these animals; although she also finds “the simultaneous demands of molting and chronic stress resulting from captivity may be part of the reason that molting birds lost significantly more weight than sparrows at other times of year.” Now the question can be asked, why did Dr. Lattin do this and what are the implications of her work? She is quite open about this, and together with her work which shows changes in behavior and body weight as a consequence of captivity, it also highlights for the benefit for future birds, “…it may be desirable to avoid bringing birds into captivity during particularly vulnerable stages (such as during molt in birds) for purposes such as translocation

DOES UNDERSTANDING OF BIRDS HAVE IMPLICATIONS FOR HUMANS?

Lattin claim (paraphrased by PETA): “Because the hormone and neurotransmitter systems I study are very similar across vertebrates, my work also has important implications for human health.” (www.christinelattin.com)

PETA response: Lattin’s experiments lack applicability to humans. Her studies of chronic stress focus on the effects of the hypothalamic-pituitary-adrenal (HPA) system, or axis, but there are significant anatomical and physiological differences between human and birds. The HPA axis regulates the secretion and release of steroid hormones and plays an important role in stress responses for both humans and animals. Birds’ adrenal glands produce steroid hormones that are different from those produced by human adrenal glands—the main adrenal hormone produced in birds is corticosterone, while in humans and other mammals it is cortisol. Unlike humans, most birds produce very low levels of aldosterone,[13] and their adrenal glands lack the distinct outer cortex and inner medulla that is characteristic of human adrenal glands. Some male birds possess an appendix epididymis that extends into the adrenal gland, while others have adrenal tissue in the epididymis, a feature that does not exist in human males.[14] With such anatomical and functional differences, the physiological response to chronic stress in birds cannot be extrapolated with any reliability to other species, including humans.

Here PETA throws up a superficial argument at best. The argument may be read as a lack of awareness, or even a deliberate ignorance about whether and how the comparative study of similarities and differences between species such as human and other non-human animals have led to major advances in our understanding of behavior, physiology, and the treatments of disease. We have covered this issue in many posts previously, including here. But even without acknowledging the benefit of the comparative approach to humans, PETA appears to be very selectively reporting. Dr. Lattin also states on her website “One of the major areas of my research is the stress response…..understanding stress in wild animal populations is important because stressors like habitat destruction, climate change, and species invasions now affect most, if not all, animal species…stress is also a major risk factor for depression, heart disease, drug abuse, and suicide in humans. Understanding more about the physiology of stress could help lead to the development of new medicines and procedures to reduce stress in humans and animals.

IS REMOVAL OF INVASIVE SPECIES FROM AN ECOLOGICAL NICHE BENEFICIAL?

Lattin claim (paraphrased by PETA): “[B]ecause they are an invasive species in North America that competes directly with native bird species for nest sites and other resources, there is no negative [conservation] impact, and potentially, even a mild beneficial impact, of removing them from the wild.”[15]

PETA response: Even if some groups designate certain species as “invasive,” this does not justify capturing, confining, and tormenting them. Lattin isn’t killing these birds in the interests of conservation—she’s holding them captive and deliberately inflicting frightening and painful procedures on them for weeks and sometimes months before finally ending their lives. This has nothing to do with conservation or protecting native species.

Again, it appears that PETA has selectively reported and paraphrased Dr. Lattin’s paper. Dr. Lattin provides four reasons for the use of this species of bird; yet PETA presents none of these other explanations. Dr. Lattin justifies quite comprehensively why she studied what she studied, and in what species; but you can decide.

House sparrows are excellent subjects for these kinds of toxicological studies for several reasons. First, they are easy to catch and do well in captivity, unlike many avian taxa, such as shorebirds. Second, because they are an invasive species in North America that competes directly with native bird species for nest sites and other resources, there is no negative impact, and potentially, even a mild beneficial impact, of removing them from the wild. Third, as a passerine species, they are taxonomically similar to many birds living in coastal and riparian areas contaminated by oil, such as seaside sparrows (Ammodramus maritimus) and tree swallows (Tachycineta bicolor). Finally, the extensive validation data necessary for receptor binding studies are missing for most avian species, but are available for house sparrows.”

DOES SYSTEMATIC DOSING ALLOW US TO DRAW GENERAL CONCLUSIONS ABOUT CONSUMPTION IN THE WILD?

Lattin claim (paraphrased by PETA):  [regarding experiments in which she fed crude oil to sparrows]: “Doing this research in a lab environment allowed me to control a lot of things that might vary in the wild and make it hard to draw clear conclusions about cause and effect. What I found was that oil specifically impacted birds’ adrenal glands, preventing them from secreting normal amounts of stress hormones.” She cites this as being among “some important discoveries.” (www.christinelattin.com)

PETA response: In these experiments, Lattin fed a uniform dose of crude oil to birds until it achieved her desired effect and she was able to see measurable results, failing to take into account the wide variability in the level of exposure that would occur in a natural setting. When she compared two groups of birds, one of which was fed oil, both groups were under so much stress that they experienced the same rate of weight loss, and one bird died of undisclosed causes.[16] Additionally, there is little correlation between sparrows and aquatic birds, the species generally affected by oil spills. Studies of penguins and ducks, some of which were conducted decades ago, have produced widely varying results, including, respectively, an increase in corticosterone caused by oil exposure, a decrease, and no difference at all.[17], [18], [19] Not only are oil-feeding studies in sparrows irrelevant—as the sparrow is a nonaquatic species and therefore unlikely to be exposed to oil spills—they also fail to yield any results that can be extrapolated to other species of birds. They cannot mimic realistic situations and, as such, lack real-world applicability to conservation problems.

Dr. Lattin’s justification for her work was covered in the preceding point evaluation; however Dr. Lattin has also discussed this quite clearly in her paper. Additionally, and in response to PETA’s claim about a lack of applicability, this research is already being used by other researchers to show health problems and deaths observed in wild dolphins and sea turtles after Deepwater Horizon were due to oil exposure.

DOES UNDERSTANDING STRESS IN BIRDS HELP US TO UNDERSTAND RESPONSE TO ENVIRONMENTAL CHALLENGE?

Lattin claim (paraphrased by PETA): “Understanding how hormones and the brain affect stress resilience will allow us to predict what kinds of individuals will be the winners and losers in the face of current and future environmental challenges.” (www.christinelattin.com)

PETA response: It stretches credulity to equate the extreme stress of capture and the subsequent terror that Lattin deliberately inflicts on birds to the pressures brought on by, for example, climate change. In its 2015 “Audubon’s Birds and Climate Change Report,”[20] the National Audubon Society stated, “The persistence of many North American birds will depend on their ability to colonize climatically suitable areas outside of current ranges and management actions that target climate change adaptation.” So for instance, a species’ chance of surviving a warming world increases if nearby higher elevations offer a more suitable habitat and the birds are not blocked from moving into those areas. Nowhere does the report mention that the ability to withstand being rattled in a cage, rolled on a cart, and physically restrained is indicative of a bird’s resilience in the face of climate change.

It is quite likely that PETA finds incredulous Dr. Lattin’s statement that understanding how hormones and the brain affect stress resilience is highly applicable to the survival of different species in response to environmental challenge. It is possible that this is simply be because PETA and its representatives do not understand how science works (at best, e.g., here). Or perhaps it is a case of deliberate ignorance (at worst). But one does not need to look far to understand the relationship between Dr. Lattin’s work and the environmental challenges that are well appreciated and of deep concern. In PETA’s own paraphrasing of Dr. Lattin, it is first obvious that she does not talk about climate change, but environmental challenges. This may include climate change, but could also include factors such as food scarcity and increased predation. Here, PETA uses the buzz word, climate change, perhaps because it is easily relatable, but it is used out of context to Dr. Lattin’s own statement.

IS SYSTEMATIC LAB BASED RESEARCH RELEVANT TO WILD ANIMALS?

Lattin claim (paraphrased by PETA): “My current research focuses on one type of stressor that has direct implications for the conservation of endangered and threatened species—bringing birds into captivity. The transition from the wild to captivity is a strong psychological stressor, even if birds have unlimited food and water and large clean cages.” (www.christinelattin.com)

PETA response: Here, Lattin claims that her experiments will somehow provide insight into the best way to mitigate the effects of captivity on endangered birds taken from their natural habitats. In a 2017 paper,[21] she purports that in order to do so, it is important to know whether these effects are caused by the release of the hormone corticosterone or other physiological effects. To test this theory, she treated one group of birds with mitotane, a drug that limits the production of corticosterone by the adrenal glands.

Both the mitotane and non-mitotane groups experienced an increase in beak wiping—a sign of distress—the longer they were kept in captivity. While the mitotane-treated group experienced a smaller increase in this behavior, the effect was slight. Moreover, this group still lost the same amount of weight and demonstrated other stress-related types of behavior, such as increased feeding and feather ruffling, to the same degree as the control group.

Despite this underwhelming result, Lattin draws the sweeping conclusion that “experimentally reducing stress-induced corticosterone may mitigate some captivity-induced behavioral changes.” She seems to be making the absurd suggestion that captive birds should be subjected to the stress of an injection every other day in order to very slightly reduce one stress-related form of behavior.

When researchers or wildlife officials take the extreme step of capturing endangered birds to treat injuries, translocate them, or include them in breeding programs, they aim to lessen the stress experienced during capture and captivity. The birds might initially be hooded, kept in a quiet room, and provided with appropriate perching material. If Lattin truly wanted to design an experiment that aimed to explore what these unfortunate captives experience, she would have tried to reduce their stress instead of cruelly compounding it.

PETA again appears to be deliberately disingenuous here, selectively reporting. The first issue worth pointing out is that Dr. Lattin does not make a sweeping conclusion, but clearly states,

Lattin: “…our data suggest that experimentally reducing stress-induced corticosterone may mitigate some captivity-induced behavioral changes.”

We might ask whether PETA understands the distinction between conditional statements and sweeping conclusions (may mitigate versus will mitigate). PETA also fails to acknowledge the great lengths that Dr. Lattin went to avoid pain and unnecessary distress in the administration of the drug mitotane:

We also wished to avoid muscle damage that can be caused by intramuscular administration. Therefore, we injected mitotane subcutaneously over the breast muscle every other day, which can reduce circulating CORT in house sparrows to the low physiological range …”

Finally, it is now unsurprising given all of the misrepresentation of facts that no consideration beyond PETA’s own agenda is given to Dr. Lattin’s clear statement of applicability in this paper:

“Broadly, our results emphasize that researchers should take behavioral and physiological differences between free-living animals and captives into consideration when designing studies and interpreting results. Further, time in captivity should be minimized when birds will be reintroduced back to the wild.

SUMMARY

What can conclude from this (very lengthy) analysis?  In part, that simple lies are easier to convey than are complicated truths. Readers here already know that and have seen any number of similar campaigns in which research is misrepresented. Campaigns against animal research continue despite the fact that the facts, context, and accurate information about the rationale, conduct, and care for animals appears in scientific papers, in scientists’ public presentations, in a range of venues, websites, books, and papers.

It is also true though that it takes a great deal of time to address each of the claims so easily made and publicized by groups like PETA.  And so often, the claims remain unaddressed. Groups like PETA may well bank on the fact that most scientists and institutions do not have – or will not take – the time to rebut claims. And they would be correct, as we’ve often seen.

In this case though, Dr. Lattin has engaged in rebuttal. It falls to the rest of the scientific community to join her. Not only in defense of her work, but in defense of public interests in making informed decisions on the basis of facts, context, and serious consideration.

CONTRIBUTIONS OF DR. LATTIN’S WORK TO SCIENCE, BASIC RESEARCH, CONSERVATION AND THE 3RS

  • Her research has been cited hundreds of times by other scientists doing research on stress, conservation, and health, including scientists working on many other bird species (including endangered species like the Florida Scrub Jay and Egyptian vultures), and dozens of other species of animals, including fish, newts, frogs, snakes, sea turtles, lizards, dolphins, whales, mice, rats, voles, ground squirrels, hamsters, cheetahs, tigers, and monkeys.
  • She has pioneered new techniques in house sparrows that allow for less invasive ways of studying stress – for example, her work validating the technique of extracting hormones from feathers, and her current research using PET and CT imaging techniques to study the brain and body.
  • Her studies on sparrows have clear and direct conservation applications. For example, her research showing that birds caught right before and during molt dramatically altered their normal physiology in response to captivity stress suggests that conservation efforts using translocation and reintroductions of birds should avoid capturing birds at these times.
  • Her research showing rapid changes in body composition in captive wild birds demonstrates that the amount of time in captivity should be minimized for wild birds that need to be released.
  • Her research showing that oil-exposed animals cannot mount a normal hormonal response to an injection of adrenocorticotropin hormone (a minimally invasive technique that does not require euthanizing animals) shows that this technique could be used to compare animals in a population where oil effects are suspected to animals in a reference, unimpacted population.
  • Many of her studies also make major contributions to understanding fundamental biological processes that are similar across all groups of vertebrate animals. For example, her research demonstrates that animals are capable of regulating hormone levels somewhat independently from receptor levels in different tissues, and that gene expression and protein expression appear to be regulated separately for stress hormone receptors in the brain. This work helps us understand how the body regulates and responds to hormonal signals.

Speaking of Research

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Research Roundup: New drug effective in treating malaria, HPV vaccine pioneers recipients of Lasker award and more!

Welcome to this week’s Research Roundup. These Friday posts aim to inform our readers about the many stories that relate to animal research each week. Do you have an animal research story we should include in next week’s Research Roundup? You can send it to us via our Facebook page or through the contact form on the website.

  • A new drug, developed in animal models, is effective in treating malaria. Researchers at Tulane University have developed a new drug that is effective against non-life-threatening cases of malaria. The drug, AQ-13, cleared the parasite responsible for the disease within one week. AQ-13 was developed for use in humans only after necessarily rigorous testing in animal models, including rats and monkeys, for its pharmacokinetics (or, the way the drug moves through the body) and safety. Because current anti-malarial drugs are developing resistance, the efficacy of this new drug is especially promising. The researchers studied 66 men in Mali living with malaria, giving half AQ13 and half a standard treatment, and both groups had similar cure rates. They plan to expand their future studies to women and children before recommending it as a new widespread treatment. The research was published in The Lancet Infectious Diseases.

Anopheles funestus, a mosquito which spreads malaria in the Sudan. CDC Public health Image Library

  • UV-treated milk led to healthier outcomes than UHT milk in premature piglets. Preterm births affect 1 in every 10 infants born in the US, so improving how we care for them is hugely important. Researchers in Denmark found that preterm piglets that were fed UV-treated milk grew quicker and developed better protection against bacteria and improved gut function when compared to piglets fed with ultra-heat treated (UHT) milk. It is hoped that such knowledge can used to improve prospects for premature human babies. The scientists had previously shown that piglets born 10-days early provided a suitable model for studying immune-system development and growth in premature babies. This study was published in the Journal of Nutrition.
  • Archaic dental practice may be replaced using squid ink. Left untreated, gum disease can lead to the destruction of mouth tissue and is the leading cause of tooth loss in adults. It is currently diagnosed using a metal probe to search for gaps between the gum and tooth that indicate disease. Periodontal probing has many drawbacks besides discomfort for the patient: it may spread disease by introducing bacteria to healthy parts of the mouth, it’s time consuming, and has limited accuracy. Thankfully, a new non-invasive imaging method that was first developed using pig jaws may put an end to painful probing. A swish of squid ink in the patient’s mouth allows pressure difference in the gums to be detected by ultrasound, so the pockets caused by disease can be spotted by dentists. The ink, which is a dark liquid full of light-absorbing particles, is safe for consumption and won’t stain teeth. This research was published in the Journal of Dental Research.

  • Scientists identify why fungi spores are not more detrimental to humans, using mice. “Humans constantly inhale fungal spores. Why don’t we suffer more invasive infections from ubiquitous fungal molds such as Aspergillus fumigatus? Working in mice, Shlezinger et al. found that neutrophils phagocytosed germinating fungal spores deep in the lungs. Once engulfed, the fungal cells underwent programmed cell death, likely induced by phagocyte NADPH oxidase. Fungal strains engineered to overexpress a fungal survivin homolog resisted cell death by inhibiting caspase-3 and -7. When a Survivin antagonist was applied, more fungal cells died. These findings may lead to therapies for immunocompromised patients threatened by invasive fungal lung infections.” This research was published in the journal Science.
  • Two pioneers of the human papillomavirus (HPV vaccine) recipients of the prestigious Lasker awards. “More than 500,000 new cases of cervical cancer are diagnosed annually, and each year, more than 250,000 women die from the malignancy” — all of which are linked to certain types of HPVs. The HPV vaccine has a long history both in terms of its development and in terms of evaluation of its efficacy. It was approved in the USA in June of 2006 and “can prevent almost all cervical cancers and protect against cancers of the mouth, throat and anus. It also combats the sexually transmitted genital warts that some forms of the virus can cause.” The development and refinement of this vaccination owes much to animal research, including rabbits, cows and dogs. You can read more about the history of this vaccine at the Lasker Foundation

Research Roundup: Zika virus used to treat brain cancer, improving bladder function after spinal cord injury and more!

Welcome to this week’s Research Roundup. These Friday posts aim to inform our readers about the many stories that relate to animal research each week. Do you have an animal research story we should include in next week’s Research Roundup? You can send it to us via our Facebook page or through the contact form on the website.

  • Zika virus used to treat lethal brain cancer. Glioblastoma is a lethal brain cancer — for adults treated with current methods, the median survival time is about 14.6 months and two-year survival is 30%. In the present study, these researchers explored in mice and donated human brain tissue samples whether Zika virus (ZIKV) — a flavivirus that induces cell death and differentiation of neural precursor cells in the developing fetus — could be used as a means of killing cancer cells. They found that ZIKV preferentially infected and killed glioblastoma stem cells (GSCs) relative to differentiated tumor progeny or normal neuronal cells. Human trials are still some ways away, but this pioneering technique could someday be used in mainstream cancer research. This research was published in the Journal of Experimental Medicine.

  • New gene editing tech promises to be even better than CRISPR. A fourth-generation DNA base editor may soon become mainstream, either complementing CRISPR or replacing it. David R. Liu, a researcher from Harvard University Professor of Chemistry and Chemical Biology, states “Approximately two-thirds of known human genetic variants associated with disease are point mutations. The fourth-generation base editors to my knowledge are the most effective forms of these molecular machines that can directly correct certain types of point mutations.” While this technique is still in the extremely early stages, we expect that rigorous safety and efficacy testing, involving animal models such as mice; similar to that which has occurred and is still occurring with CRISPR Cas9. The research was published in the journal Science Advances.

Dachshund image by Becky Smith

  • Pioneering gene therapy approved for leukemia in the USA. CAR T is a pioneering type of gene therapy for cancer. CAR T cells are equivalent to given patients a “living drug”. “The therapy requires drawing blood from patients and separating out the T cells. Next, using a disarmed virus, the T cells are genetically engineered to produce receptors on their surface called chimeric antigen receptors, or CARs.” While this form of therapy has been in use in various small scale human trials, it is the first approval in the world for a type of CAR T therapy. Much of its success is due to pre-clinical safety and efficacy testing in animals models, such as mice — which we have covered previously. The “living drug”, known as Kymriah (or tisagenlecleucel), was developed by the SWISS based company Novartis, and is charging $475,000 for the life-saving treatment.
  • Malaria parasite in howler monkeys has infected humans in Brazil. There have been almost 1,000 causes of Malaria since 2006, leading scientists to try and discover the source of a disease which was once thought to be eradicated from the region. Analysis of patient DNA showed that the infections came from Plasmodium simium, a parasite that is found in howler monkeys. Zoonotic diseases, capable of transferring from animals to humans, are hard to treat, though the researchers do not believe it was transferred via a mosquito vector. One of the authors of the study noted: “However, its unique mode of transmission via monkeys and the fact that it occurs in areas of high forest coverage mean that zoonotic malaria poses a unique problem for malaria control efforts and may complicate the drive towards eventual elimination of the disease.” This research was published in The Lancet.

Say NO to the harassment of Christine Lattin by PETA activists

Please leave a comment of support at the bottom of this article for Christine, and please share with your colleagues to raise awareness of the vile and irresponsible tactics of PETA in their targeting of a young researcher at Yale University.

What would someone need to do to deserve threats online, protests at their place of work, and the publication of their image and home address? According to PETA, they would just need to be a researcher that works on animals.

PETA activists protesting outside the annual meeting of the Society for Behavioral Neuroendocrinology in Long Beach, California, in June 2017

Christine Lattin is a post-doctoral researcher at Yale University who studies birds in order to better understand the impact of stress on animals and humans. In her own words:

The focus of my research is to understand how different neurotransmitters and hormones help animals successfully choose mates, raise young, escape from predators, and survive harsh winters and other challenging conditions. One of the major areas of my research is the stress response. While stress helps animals and humans survive and cope with challenges, too much stress is bad and leads to health problems. Understanding stress in wild animal populations is important because stressors like habitat destruction, climate change, and species invasions now affect most, if not all, animal species.

Christine believes in openness and transparency, which is why she runs a website where she explains more about her research – this can help educate the public on the importance of the work she does. It is well worth a read: www.christinelattin.com. All of Dr Lattin’s work has been approved by the Yale Institutional Animal Care and Use Committee, and all of it must comply with the Ornithological Council’s ‘Guidelines to the use of wild birds in research’.

PETA do not like animal research, and PETA do not like Christine Lattin. Why did they choose to focus on her? Who knows. Is it because she is young? Female? Not yet tenured? While avian research is not a common target for animal rights groups, the fact she studies stress would fit the typical choice of target.

In May, PETA set up an alert to allow individuals to send emails to administrators at Yale University, demanding that the institution “put an immediate end to Lattin’s experiments on birds”. Her research is presented as cruel, curiosity-driven torture. These misleading claims are put next to images of Christine for any activist to see.

Let us briefly examine some of the claims made by PETA:

“Some birds were fed crude oil, and others’ legs were wounded without any pain relief. After weeks and sometimes months of repeated abuse, they’re then killed. Not only are the experiments extremely cruel, they’re also wasteful because important physiological differences between species make the results inapplicable to humans or other birds.”

The oil research provides an example of how Christine’s research is misrepresented. Context is crucial. The study involved putting small amounts of oil into the food (equal to 1% of food weight) of captured wild sparrows. While there were no obvious outward signs this had any effect, and many potential biomarkers of oil exposure in the blood were also normal, blood sampling revealed that birds were not able to secrete normal concentrations of stress hormones after exposure to a standardized stressor (a brief period of restraint in a clean, breathable cloth bag) and an injection of adrenocorticotropic hormone. Contrary to the PETA claim that such research was not applicable to other species, Christine explicitly states the relevance of her research to other birds in her publication: “as a passerine species, they are taxonomically similar to many birds living in coastal and riparian areas contaminated by oil, such as seaside sparrows (Ammodramus maritimus) and tree swallows (Tachycineta bicolor).” Furthermore, this research is already being used by other researchers to show health problems and deaths observed in wild dolphins and sea turtles after Deepwater Horizon were due to oil exposure. On the claim that birds’ “legs were wounded without any pain relief”, this is categorically false. A brief glimpse at the original paper shows that the birds were anesthetised (using isoflurane, the general anesthetic recommended by the Ornithological Council because of its safety in birds):

“[W]e administered a small superficial wound to either the left or right thigh of birds using a 4 mm biopsy punch […] Prior to wounding we anesthetized birds using isoflurane.”

The PETA alert began a string of abuse on Twitter:

PETA activist tweets against Christine Lattin

Click to Enlarge

From the merely aggressive “All you do is torture and slaughter birds for USELESS research” to the outright threatening “She should be put out of her misery” and “I am the bump in the night for you Christine Lattin unless you resign”. One hopes that PETA will be policing these comments and reporting them to Twitter, though I sadly doubt it.

It is worth taking a moment to thank the many people who came to Christine’s aid on Twitter (and there were many people). One user noted:

Another noted the hypocrisy of PETA, noting a recent incident where PETA had to pay $49,000 to settle a lawsuit after they stole and put down a young girl’s pet chihuahua.

As some might expect, the comments have not been limited to Twitter. As a result of the PETA campaign, Christine has received numerous hateful and threatening emails. No researcher, particularly one still taking their first steps in research, should have to deal with this sort of harassment.

In the latest stunt, PETA activist (note the PETA email address), has organised a protest outside Christine’s home.

A screenshot from a home protest set up by PETA activist to be outside the home of Christine Lattin. Her address has been blotted out, and we have highlighted certain details in red.

There are four things to note from this event:

  1. A protest is planned outside Christine’s home (where her husband and child also live)
  2. Inflammatory language and false claims are made in the text.
  3. It is set up by an official PETA campaigner, Katerina Davidovich. The fact she is an official PETA campaigner is evidenced by her PETA email address.
  4. She/PETA will be providing all materials for the protest.

PETA are irresponsible in their decision to put the home address of Christine and her family in the public domain, next to false claims. We roundly condemn PETA for their actions and hope they not only remove all details of their upcoming home protest but also issue a prominent apology to Christine for the harassment she has received.

Please join us in condemning this campaign of harassment by PETA. We hope many scientists will leave a message of support for Christine alongside their name, role, and institution.

Speaking of Research

Does talcum powder cause ovarian cancer? Weighing up the human and animal studies

In this article, Justin Varholick, investigates the evidence on whether talcum powder can cause ovarian cancer. Over the years, several courts have ruled that talcum powder can cause ovarian cancer, while the scientific evidence suggests otherwise. In light of Ovarian Cancer Month, it is important to highlight how animal and human studies can improve our understanding of the disease, and prevent misinformation spread from the media. This article outlines that both animal and human studies are not perfect. Animal studies sometimes do not have proper controls and human studies suffer from bias. The current research suggests no direct link between talc and cancer, but more research is certainly necessary.

Ovarian cancer is a serious disease affecting around 22,000 women in the United States and contributing to around 14,000 deaths each year. Since the 1960s the American public has questioned whether the use of talcum powder – for soothing dry skin, absorbing sweat, and preventing chafing of the thighs — increases women’s’ risk for ovarian cancer. This speculation began after acknowledging the risks of asbestos and public theories that asbestos was in talc products; however, cosmetic grade talc undergoes strict quality control and does not contain asbestos.

Image by Austin Kirk

Multiple studies on rodents, non-human primates, and humans have investigated the link between talc and cancer since the 1960s. Overall the results are inconsistent; some studies suggest talc is associated with ovarian cancer while others suggest talc is not carcinogenic. Recently, despite these inconsistencies, a Los Angeles jury ordered Johnson & Johnson to pay $417 million to a woman who blamed her terminal ovarian cancer on the use of baby powder — this is just one of many lawsuits against Johnson & Johnson over their talc powder. In light of this recent event I would like to delve into the animal and human studies investigating the link between talcum powder and ovarian cancer.

Is talcum powder a carcinogen?

Empirical studies first began on rodents such as hamsters, rats, and mice; however, these studies only focused on whether talc was a carcinogen in general. Researchers chose rodents because it is relatively easy to systematically administer talc to rodents via inhalation. Furthermore, rodents — especially the laboratory rat — are particularly sensitive to forming malignant tumors in the lungs when exposed to chemicals via inhalation regardless of the chemical itself. Therefore, by using rodents there is an increased chance of detecting an effect of cancer following exposure to talc via inhalation — if one is present. It is important to note here that although humans are exposed to talc by inhalation or via topical application, the specific method of applying talc is not important when determining general carcinogenicity.

For one of the first studies investigating talc exposure and cancer in rodents, researchers first gathered information on how much baby powder human infants were regularly exposed to – although infants are usually exposed via topical application and rodents are exposed via inhalation. Using this information they designed an experiment using hamsters and exceeded the amount of talc human infants are normally exposed to by 30 to 1700 times — depending on the experimental treatment group. The scientists also formed a control group that was exposed to a negative dust control; titanium dioxide. This control is important because increased levels of dust in the air can lead to chronic inflammation of the lungs, which increases the risk of malignant tumors — independent of particle type (e.g. talc powder, titanium dioxide, toner, carbon black, etc.). Controlling for dust and exceeding levels of normal exposure, the study reported no difference between the groups in body weight, survival, or signs of cancer in the larynx, trachea, lungs, liver, kidney, stomach, uterus, ovaries, or testes of these hamsters.

Further studies were conducted on rodents — specifically mice and rats — that did find an effect linking cancer to talc; however, these studies were confounded. One study in particular found that female rats and mice exposed to high levels of talc via inhalation for 4 months had a higher risk of lung cancer. Unfortunately, this study did not use a titanium dioxide control group, thus the finding could be an artefact of chronic inflammation from air particles — as discussed above. Furthermore, this study was unable to identify another biological mechanism beyond chronic inflammation responsible for the onset of cancer.

In summary, these rodent studies allowed scientists to exceed normal exposure levels and use an animal with increased sensitivity to the treatment in question. However, proper control groups must be used to help elucidate whether the effect is an artefact. Importantly, these studies were only interested in whether talc is a possible carcinogen, not whether ovaries exposed to talc have increased risk of cancer specifically. Overall, these studies were unable to find a link between talc and risk of cancer, beyond chronic inflammation from increased levels of air particulates.

Can talcum powder be found in the ovaries?

Some studies in animals and humans have been particularly focused on finding a link between talc use and ovarian cancer — not just whether talc is a carcinogen. To understand the plausibility of this link, these studies first needed to establish whether it is possible for particles of talc to migrate into the genital tract after being applied topically to the perineal region (area between vagina/scrotum and anus). A simple understanding of biophysics led many to conclude that it was impossible for the particles to travel up the vagina, cross the cervix, travel through the uterus, and then “swim” upstream through the oviducts; without being assisted by some form of locomotion. Nonetheless, some studies using animals investigated whether it was a possibility. Specifically, one study using female cynomolgus monkeys (Macaca fascicularis) — an animal model anatomically and physiologically comparable to human female — investigated whether carbon black particles could reach the oviducts or ovaries. This study was unable to conclude that carbon black particles could indeed travel up to the oviducts or ovaries.

Image by Noveprim

Further studies were done with human females that applied talcum powder to their underwear or perineal region daily that also had ovarian or pelvic cancer; which required surgical removal of the ovaries.  After removing the ovaries, scientists used microscopy techniques to scan the ovaries and identified low numbers of particles that were relatively small in size in about 50–75% of cases (multiple studies). Thus, although talc can be found in or around ovarian tissue the amount found was considered too small to cause ovarian cancer. It has also been noted that findings from these studies were widely inconsistent and were confounded by women lying in a supine or Trendelenburg position — which may aid in the surgery of the pelvic region but is also used to aid in vitro fertilization.

Thus, studies in both animals and humans cannot definitively suggest talc can translocate from the perineal region to the ovaries, which may be necessary for the talc to affect the ovaries. Nonetheless, both animal and human studies have been limiting; studies with monkeys only used a particle similar to talc and human studies involved a lying position that aided in the migration of talc up the genital tract.

How many women using talcum powder get ovarian cancer?

Two types of human studies have investigated, and continue to investigate, the link between talc and ovarian cancer; case-control and cohort studies. The case-control studies gather a group of women diagnosed with ovarian cancer and a group of women with no ovarian cancer. They then ask all women to retrospectively discuss their use of talc on the genital area throughout their life — noting frequency and average amount. The obvious downside to this type of study is that it is open to reporting bias. Some women may forget when or how often they used talc, while others may overestimate their use and further bias may occur if there is an expectancy that talc may have contributed to the onset of ovarian cancer. In contrast, the cohort studies gather a group of women early in life and then have them report in real-time throughout their life how often they use multiple products — including products with talc. After several decades they then compare how many women are diagnosed with ovarian cancer and used talc products, diagnosed with ovarian cancer and did not use talc products, etc. Cohort studies, however, are often limiting because few women are actually diagnosed with ovarian cancer compared to those that are not.

A recent meta-analysis, published this year, gathered 24 case-control and 3 cohort studies investigating the use of talc on the perineal region and its relation to ovarian cancer. Gathering all of these studies into a single analysis, they found that talc powder use on the perineal region is associated with a small increased risk of developing ovarian cancer; however, case-control studies largely contributed to this association — which have obvious disadvantages as outlined above. This positive association was also limited to a single type of ovarian cancer; identified as serous carcinoma — the most common type of ovarian cancer (types of ovarian cancer). Importantly, if reporting bias is affecting the case-control studies, then the association between talc use and ovarian cancer should not be limited to a single type of ovarian cancer. The authors also note that publication bias may also be affecting the case-control studies, meaning that some hospitals may gather information about talc use and ovarian cancer but do not publish their findings because they do not find a link between the two.

In summary, studies with humans do suggest that there is a small positive association between talc use and ovarian cancer; however, these studies are largely limited to case-control studies which have disadvantages of reporting and publication biases. Furthermore, these studies can only tell us about the relative risk of ovarian cancer when using talc. They cannot tell us about the biological basis linking talcum powder use to cancer.

Talcum powder does not cause ovarian cancer

The current evidence from both animal and human studies does not suggest that talc can be directly linked to ovarian cancer. However, both animal and human studies are not perfect. Studies using animals sometimes lack important controls and are not able to properly investigate the specific question at hand without proper animal models (i.e. cynomolgus monkeys). However, animals can be utilized in investigating whether talc is a carcinogen in general because some are especially sensitive to different types of treatments. Studies with humans also have disadvantages due to limitations of subject pools and biases. Despite this, studies with humans somewhat consistently find a link between talc and ovarian cancer, thus humans may be particularly sensitive to talc beyond other animals — although this is highly unlikely given that studies on other mammals suggest no direct relationship.

Importantly, there are many more studies on animals and humans that investigate the link between talc and cancer that I did not include in this brief discussion. Therefore, it is important to note that in a recent review in 2015, the Cosmetic Ingredient Review Expert Panel reported that talc is safe to use in standard practices with normal concentrations. They also note that there is:

  • Absence of persuasive evidence that talc can migrate from the perineum to the ovaries
  • Lack of consistent statistically significant positive associations across studies
  • Failure to rule out plausible alternative explanations of statistically significant results, including biases, risk factors, and exposure to misclassifications
  • Absence of a plausible biological mechanism
  • Lack of credible, defensible evidence of carcinogenicity from results of epidemiological studies of occupational exposures and animal bioassays

Thus, more research is necessary to determine whether talc is linked to ovarian cancer, despite what the Los Angeles courts might say.

Justin Varholick

 

References

Berge, W., Mundt, K., Luu, H. and Boffetta, P. 2017. Genital use of talc and risk of ovarian cancer: a meta-analysis. European Journal of Cancer Prevention.

Fiume, M.M., Boyer, I., Bergfeld, W.F., Belsito, D.V., Hill, R.A., Klaassen, C.D., Liebler, D.C., Marks, J.G., Shank, R.C., Slaga, T.J., Snyder, P.W. and Andersen, F.A. 2015. Safety assessment of talc as used in cosmetics. International journal of toxicology 34(1 Suppl), p. 66S–129S.

Reid, B.M., Permuth, J.B. and Sellers, T.A. 2017. Epidemiology of ovarian cancer: a review. Cancer biology & medicine 14(1), pp. 9–32.

Wehner, A.P. 2002. Cosmetic talc should not be listed as a carcinogen: comments on NTP’s deliberations to list talc as a carcinogen. Regulatory Toxicology and Pharmacology 36(1), pp. 40–50.