European Scientists Join Chorus of Government and Scientific Organizations Acknowledging the uselessness of Homeopathy

The evidence that homeopathy is ineffective for any and all medical problems and is nothing more than a placebo has grown steadily for over a century. Many reviews of the scientific research have been done, and despite hundreds of studies, no reliable evidence exists to support the core principles of homeopathy or the actual real-world benefits claimed by its practitioners. I reviewed this evidence in detail in support of a resolution before the American Veterinary Medical Association (AVMA) to declare homeopathy ineffective and discourage its use in veterinary patients. I also exhaustively examined the evidence provided in support of homeopathy and discussed why it is unreliable and unconvincing. The AVMA’s scientific advisory body, the Council on Research, agreed that “that there is no clinical evidence to support the use of homeopathic remedies for treatment or prevention of diseases in domestic animals.” Unfortunately, politics won out over truth, and the AVMA refused to acknowledge the obvious—that homeopathy is useless and veterinarians promoting it are deceiving animal owners.

Several scientific bodies around the world have reviewed the same evidence and come to the same conclusion. The United Kingdom House of Commons Science and Technology Committee conducted hearings and a thorough evidence review and came to stark and clear conclusions:

In our view, the systematic reviews and meta-analyses conclusively demonstrate that homeopathic products perform no better than placebos.

There has been enough testing of homeopathy and plenty of evidence showing that it is not efficacious. Competition for research funding is fierce and we cannot see how further research on the efficacy of homeopathy is justified in the face of competing priorities.

For patient choice to be real choice, patients must be adequately informed to understand the implications of treatments. For homeopathy this would certainly require an explanation that homeopathy is a placebo. When this is not done, patient choice is meaningless. When it is done, the effectiveness of the placebo—that is, homeopathy—may be diminished.

We recommend that the MHRA remove all references to homeopathic provings from its guidance other than to make it clear that they are not evidence of efficacy.

We consider that the way to deal with the sale of homeopathic products is to remove any medical claim and any implied endorsement of efficacy by the MHRA—other than where its evidential standards used to assess conventional medicines have been met—and for the labelling to make it explicit that there is no scientific evidence that homeopathic products work beyond the placebo effect.

It is unacceptable for the MHRA to license placebo products—in this case sugar pills—conferring upon them some of the status of medicines. Even if medical claims on labels are prohibited, the MHRA’s licensing itself lends direct credibility to a product. Licensing paves the way for retail in pharmacies and consequently the patient’s view of the credibility of homeopathy may be further enhanced. We conclude that it is time to break this chain and, as the licensing regimes operated by the MHRA fail the Evidence Check, the MHRA should withdraw its discrete licensing schemes for homeopathic products.

By providing homeopathy on the NHS and allowing MHRA licensing of products which subsequently appear on pharmacy shelves, the Government runs the risk of endorsing homeopathy as an efficacious system of medicine. To maintain patient trust, choice and safety, the Government should not endorse the use of placebo treatments, including homeopathy. Homeopathy should not be funded on the NHS and the MHRA should stop licensing homeopathic products.

Despite significant political resistance, including from members of the royal family, this message has been heard, and homeopathy has been banned from government-provided healthcare in the UK.

The government of Australia conducted a similar, exhaustive review over several years, with plenty of opportunity for input from supporters of homeopathy. This review also agreed with those that went before, concluding:

Based on all the evidence considered, there were no health conditions for which there was reliable evidence that homeopathy was effective. No good-quality, well-designed studies with enough participants for a meaningful result reported either that homeopathy caused greater health improvements than placebo, or caused health improvements equal to those of another treatment.

NHMRC concludes that there are no health conditions for which there is reliable evidence that homeopathy is effective. Homeopathy should not be used to treat health conditions that are chronic, serious, or could become serious. People who choose homeopathy may put their health at risk if they reject or delay treatments for which there is good evidence for safety and effectiveness.

Historically, the U.S. is less amenable to government regulation of health care than other developed countries. Homeopathy was grandfathered in to the FDA regulatory system by politicians in the 1930s, and since then there has been little political will to challenge the practice despite the powerful evidence against it. In 2016, however, both the Federal Trade Commission (FTC) and the FDA conducted reviews, with public comment, regarding their oversight of homeopathy. No report or action has yet resulted from the FDA review, and given the anti-science and anti-regulatory views of the current administration, it seems unlikely this will change any time soon. However, the FTC, which regulated advertising of healthcare products, did come out with a strong pro-science position on homeopathy last year:

For the vast majority of OTC homeopathic drugs, the case for efficacy is based solely on traditional homeopathic theories and there are no valid studies using current scientific methods showing the product’s efficacy.  Accordingly, marketing claims that such homeopathic products have a therapeutic effect lack a reasonable basis and are likely misleading in violation of Sections 5 and 12 of the FTC Act.

Nevertheless, truthful, nonmisleading, effective disclosure of the basis for an efficacy claim may be possible.  The approach outlined in this Policy Statement is therefore consistent with the First Amendment, and neither limits consumer access to OTC homeopathic products nor conflicts with the FDA’s regulatory scheme.  It would allow a marketer to include an indication for use that is not supported by scientific evidence so long as the marketer…effectively communicates to consumers that (1) there is no scientific evidence that the product works and (2) the product’s claims are based only on theories of homeopathy from the 1700s that are not accepted by most modern medical experts.

Essentially, what the FTC has said is that one can claim homeopathy works only if one admits that there is no scientific evidence for this claim and that it is based on pre-scientific folk beliefs with no validity.

The most recent addition to this chorus of official voices acknowledging the lack of benefit to homeopathy is the European Academies Science Advisory Council (EASAC), which recently issued a strong statement warning of the misleading nature of claims for homeopathy.

EASAC, the European Academies Science Advisory Council, is publishing the present Statement to reinforce and reiterate this extensive and well-founded critique and to encourage and support (i) policy makers in the EU in taking a more explicitly evidence-based approach to assessing the claims for homeopathy and (ii) all those interested in stimulating better public engagement with these contentious issues and in improving consumer’s rights to correct information.

…there is no robust, reproducible evidence that homeopathic products are effective for any known diseases, even if there is sometimes a placebo effect. Moreover, homeopathy can actually be harmful: by delaying or deterring a patient from seeking appropriate, evidence-based, medical attention and by undermining patient and public confidence in scientific evidence.

From analysis of the appropriately controlled, verifiable evidence base, any claimed efficacy of homeopathic products in clinical use can be explained by the placebo effect or attributed to poor study design, random variation, regression towards the mean, or publication bias…The scientific claims made for homeopathy are implausible and inconsistent with established concepts from chemistry and physics.

The promotion and use of homeopathic products risks significant harms as mentioned above. In addition, homeopathy raises issues of concern for patient informed consent if health practitioners recommend products which they know are biologically ineffective. There are also potential safety concerns for homeopathic preparations because of poorly monitored production methods.

  • There should be a consistent regulatory requirement for claims for the efficacy, safety and quality of all medicinal products to be based on verifiable and objective evidence, commensurate with the claims being made. The necessity for robust data applies to products for both human and veterinary medicine.

  • Public health system budgets are under increasing pressure. Evidence-based public health systems should not offer reimbursement for homeopathic products and services unless they are demonstrated to be efficacious and safe by rigorous testing.

The growing willingness of scientists, individually and through their organizations, and of regulatory bodies to confront pseudoscience and unscientific nonsense like homeopathy is an encouraging sing, and it is beginning to have an impact, as seen in the withdrawal of NHS support for homeopathic treatment. Ultimately, the more willing we in science are to challenge unscientific claims and methods and to take the time to explain the evidence to people, the more the public will be able to make sound, fully informed healthcare choices, which is what this blog is all about.

Posted in Homeopathy | 3 Comments

American Animal Hospital Association (AAHA) 2017 Canine Vaccination Guidelines

In previous discussions of vaccination recommendations, I have referenced several clinical guidelines that review the existing evidence and provide recommendations for vaccination. The American Animal Hospital Association (AAHA) and American Association of Feline Practitioners (AAFP) guidelines are quite extensive and useful documents in making decisions about vaccination. AAHA guidelines are, unfortunately, usually prepared by small groups of experts with little transparency, and they are not always a model of evidence-based guideline development (for a great model, see the RECOVER guidelines for small animal CPR). That said, the vaccination guidelines do a good job of summarizing the complex and sometimes contradictory evidence and making reasonable recommendations.

AAHA has update the canine vaccination guidelines, and has presented them in a new form. The 2017 AAHA Canine Vaccination Guidelines are now primarily an online document divided into sections that make finding the answer to specific vaccination questions quite easy. In terms of providing a summary of existing vaccine science and giving a general overview of the issues, the web-based format is clunky and harder to use than a traditional journal article. But in terms of giving direct answers to questions vets and dog owners typically have about when and how to use specific vaccines, the format works well.

The new guidelines also add detail to subjects only lightly discussed in the previous version, including the use of antibody titers to guide vaccination and how to handle animals with uncertain vaccine histories or overdue for boosters of vaccines given previously.

There is nothing revolutionary or earth-shattering in the new guidelines, and they will undoubtedly not satisfy the concerns of those with deep anxieties or objections to routine vaccination practices. The recommendations are very similar to previous versions, and there will be few changes for those of us who have been following these guidelines in the past. Thorny questions like how often, or if, boosters of core vaccines should be given are not always directly answered.

The previous guidelines summarized the evidence that, for example, vaccination for canine parvovirus (CPV) and canine distemper (CDV) should provide immunity for a minimum of three years and likely protects most dogs for at least 5-7 years and possibly longer (when given properly as a series to puppies with a booster at about one year). The currently guidelines recommend intervals for these vaccines of “three years or longer”, which leaves the exact interval to the discretion of vets in practice. This makes sense in many ways, since the risks and benefits of vaccination for individual animals depends on exposure risk, lifestyle, health, medical treatment, and many other variables. Ultimately, there is no single right answer for every dog.

Unfortunately, it is easier for most vets to choose an arbitrary recommendation to make for all their patients. Right now, many choose three year intervals for these vaccinations because that number was specifically suggested in the AAHA guidelines. When I have suggested longer intervals might be appropriate, many of my colleagues are understandably wary of deviating from what all the major veterinary schools and most other practices are doing for fear of being blamed for any failure of protection that might occur. And, of course, none of this will satisfy those who think little or no vaccination is necessary at all.

Despite the inevitable compromises and limitations in the evidence, however, the AAHA guidelines are an excellent resource for vets and dog owners wishing to make rational, science-based decisions about how best to protect dogs from vaccine-preventable disease.

Posted in Science-Based Veterinary Medicine, Vaccines | 30 Comments

Pets deserve Evidence-based Medicine Too!

Here’s a recent interview I did for NPR on the SkeptVet Blog and the need for skeptical, evidence-based medicine for our animal companions.

Why does the world need skeptical veterinarians?

Pet owners need to know the pros and cons of health care options for their pets to make good decisions. “Skeptic” doesn’t mean someone who automatically rejects new or unfamiliar ideas. It’s someone who refrains from judging a claim until they have examined the evidence dispassionately — someone who gives preference to scientific evidence over personal experience, anecdote, tradition or history.

Posted in Presentations, Lectures, Publications & Interviews | 16 Comments

Discussion of the ACVBM Application for Specialty Status for Herbal Veterinary Medicine

About six months ago, I reported on the application of a group of veterinarians belonging to the American College of Veterinary Botanical Medicine (ACVBM) for status as a medical specialty group. I explained the main reasons why, despite the potential value of herbal medicine, such status is not warranted at this time:

  1. There is very little high-quality or reliable scientific evidence to support the use of herbal products in veterinary patients.
  2. Herbal prescribing is dominated by Chinese Medicine, Ayurveda, and other unscientific folk belief systems, and those proponents who take a more scientific approach are a small minority generally unwilling to reject the claims or methods of alternative herbal medicine.
  3. Herbal products are unregulated, inconsistent and unpredictable in their chemical composition, frequently contaminated with toxins or even undisclosed pharmaceutical drugs, and almost none have been properly tested for safety or efficacy. There is ample evidence of serious harm to human patients from herbal products. The ACVBM supports industry self-regulation rather than the kind of government oversight accepted as necessary for pharmaceutical medicines without any sound reason for doing so.
  4. The majority of the leadership of the ACVBM are dedicated proponents of alternative medicine, not only for herbal products but homeopathy, acupuncture, energy medicine, and many other unproven or pseudoscientific practices. Many have said clear and troubling things that display a contempt for science and science-based medicine and a desire to use the appearance of scientific methods to gain acceptance for alternative practices. This makes it very likely that approval of the ACVBM as a specialty board would serve as a Trojan horse for the legitimization of other alternative therapies.
  5. The potential of herbal medicines would be better explored from a rigorously scientific approach involving specialists in pharmacology, toxicology, nutrition, epidemiology, and other existing medical specialties.

The deadline for public comment on the application is September 1. As this date approaches, there has been more discussion of this issue. The Veterinary information Network (VIN) News Service recently published an article on the debate in which I and other skeptics, as well as several proponents of herbal medicine are quoted at length.

The American College of Veterinary Internal Medicine (ACVIM) has taken a public position opposing the ACVBM application.

Proponents of the application have also been active, including efforts to gain support from the American Holistic Veterinary Medical Association (AHVMA), the leading advocacy group for alternative veterinary medicine . This actually helps to support and illustrate my objection #4 above. Even members of the ACVBM who claim to support a scientific approach and eschew the alternative roots of herbal medicine are providing links to the AHVMA templates for letters supporting the petition. Herbal medicine is still inextricably linked to alternative medicine, and this will not be fixed by setting up a specialty board run by alternative practitioners.

Similarly, the current president of the ACVBM, Dr. Ihor Basko, has made this statement in his appeal to supporters to write letters in favor of the petition:

Surprisingly there is much opposition to the college, mostly from veterinarians. It also appears that the pharmaceutical industry has hired “trolls” disguised as pet owners to write letters in opposition to the college.

Dr. Basko is an advocate of Chinese Medicine and many varieties of unscientific medical practices, and this sort of consipracist nonsense is typical of the ideology and rhetoric of the alternative medicine community. To suggest the ACVBM will be a rigorously and strictly scientific group when practitioners like Dr. Basko dominate the leadership is disingenuous and not convincing.

I encourage anyone dedicated to truly science-based veterinary medicine to write or email the American Board of Veterinary Specialities before September 1 and declare your opposition to this application. I have provided the contact information and a sample letter below:


American Board of Veterinary Specialties
c/o Mr.David Banasiak
1931 N. Meacham Rd, Suite 100
Schaumburg, IL, 60173

Dear Mr. Banasiak:

I am writing to oppose the recognition of the American College of Veterinary Botanical Medicine (ACVBM) as a veterinary specialty organization. The ACVBM does not meet the core criteria set forth by the ABVS, and recognition would not be in the best interests of animal owners nor the veterinary profession.

Botanical medicine is not recognized as a medical specialty, in human or veterinary medicine, in the U.S., Europe, Australia, or most other scientifically advanced nations because the research evidence concerning herbalism and botanical remedies does not support this status. Prescribing practices are largely untested and based on folk medicine beliefs and traditions, and most herbal products are untested and un-regulated. Very few herbal therapies have been validated by the type of high-quality clinical trial evidence typically required for pharmaceutical medicines. Problems with mislabeling and contamination by toxic adulterants and pharmaceuticals is frequently reported for herbal products, with documented harm to patients. While there is great potential for medicinal use of plant-derived compounds, this potential can best be realized through pharmacognosy and other conventional forms of scientific research under the auspices of clinical pharmacology, toxicology, and other existing medical specialties.

The primary distinction the ACVBM offers between its approach and current conventional research and application of herbal remedies is the use of “traditional knowledge” to guide herbal prescribing. This means that the theories and practices of folk medicine traditions are considered sufficient to guide the use of herbal medicines, even when controlled research evidence is unavailable or contradicts traditional theory and practice. Almost none of this “traditional knowledge” has been validated by controlled research, and much of it is incompatible with established scientific principles and knowledge.

Illustrating the reliance of the ACVBM on unscientific principles is the affiliations and practices of the members of the ACVBM Organizing Committee. Nearly all are affiliated with the Chi Institute or other Chinese Medicine organizations, and most are practitioners of Traditional Chinese Medicine (TCM). TCM is an alternative system for understanding health and disease which is entirely independent from, and inconsistent with, science-based medicine. It views disease as arising from imbalances of mystical forces, such as Chi or Yin and Yang, and metaphorical humors such as Wind, Damp, Heat, and so on. Diagnoses such as “Rebellious Chi” or “Excess Wind” are made based on behavioral and historical information, tongue color and texture, pulse quality, and other traditional means. These diagnoses are then used to guide the use of herbal products, which are categorized in their effects by taste, appearance, and historical use rather than any scientific analysis of their components or physiologic effects. TCVM is not a specialty area within scientific veterinary medicine, it is an alternative to it. Recognizing the ACVBM would effectively identify TCM herbalism as a legitimate scientific medical practice without appropriate evidence to support this status.

Additionally, a majority of the ACVBM leadership is also affiliated with the American Holistic Veterinary Medical Association (AHVMA), and many have served in the leadership of this group. The AHVMA promotes and defends every type of alternative medicine, from herbalism and acupuncture to homeopathy and faith healing. Most of the Organizing Committee members promote or utilize numerous alternative therapies other than herbal medicine, and many have been publicly critical of conventional and evidence-based medicine and have recommended greater reliance on traditional knowledge and personal experience. These views do not support a rigorous scientific standard for developing safe and effective therapies and would not promote more evidence-based and higher-quality patient care.

The best way to develop the potential of plant-based medicines is to continue rigorous scientific research into herbal remedies, based on established scientific principles and methods. This progress can best be accomplished through the existing veterinary specialty areas. Traditional use may suggest testable hypotheses, but it is not a reliable guide for prescribing. Recognition of the ACVBM would be counterproductive in encouraging folk medicine-based approaches and in giving the ABVS imprimatur of scientific legitimacy to theories and practices which do not merit it. This would mislead veterinarians and animal owners and encourage the promotion of unscientific alternative practices.

Posted in Herbs and Supplements | 5 Comments

Evidence Update: Biologic Plausibility of Curcumin (Turmeric) Very Low

In 2013, I wrote about the burgeoning popularity of the spice turmeric as a medicinal herb. At the time, my conclusions were:

Overall, there is no compelling clinical evidence in humans supporting any use of curcumin or other turmeric compounds…There is virtually no clinical research in companion animals, and what there is does not support claims of benefit from turmeric compounds. Finally, the limited research to date suggests a few potential risks but the significance of these is unclear.

Since then, there have been many additional in vitro or lab animal studies, but no significant clinical trials in companion animal species. The pre-clinical research continues to find interesting biological activity of curcumin and other turmeric compounds which might, or might not, lead to clinically useful effects. At this point, there isn’t much new evidence that supports altering my previous conclusions.

However, one new review has looked at the biologic plausibility of curcumin, which is one factor in assessing the potential medicinal applications. This paper, somewhat surprisingly, suggests that the basic biochemistry of curcumin makes it unlikely to be a clinically useful remedy.

Nelson KM. Dahlin JL. Bisson J. et al. The Essential Medicinal Chemistry of Curcumin J. Med. Chem. 2017;60:1620?1637.

The authors review the pre-clinical and clinical trial literature for curcumin with an eye to features that would make the compound a better or worse candidate medicine. They conclude that its basic biochemical features make it unlikely to be useful but highly likely to generate false positive results if not tested with a clear understanding of its properties:

The likely false activity of curcumin in vitro and in vivo has resulted in >120 clinical trials of curcuminoids against several diseases. No double-blinded, placebo controlled clinical trial of curcumin has been successful. This manuscript reviews the essential medicinal chemistry of curcumin and provides evidence that curcumin is an unstable, reactive, nonbioavailable compound and, therefore, a highly improbable lead.

Curcumin…has shown excellent promise in early testing (in vitro), even though this testing may have been bedeviled by design problems that led to several misfires. The structure of 1 suggests that it might be unstable in a biological setting, and in fact, it is: both its in vitro and in vivo stabilities are abysmal…relative to commercial drugs.

To our knowledge, [curcumin] has never been shown to be conclusively effective in a randomized, placebo-controlled clinical trial for any indication. Curcumin is best typified, therefore, as a missile that continually blows up on the launch pad, never reaching the atmosphere or its intended target(s).

While these failures would normally end further research on its use as a therapeutic, they apparently have not deterred researchers interested in its development.

Given its low systemic bioavailability, we remain highly skeptical that an oral dose of 1 can ever be effective in human clinical trials that are translated from reports of in vitro activity… the lack of any observed efficacy of oral curcuminoids in clinical trials where it was given in high doses does not bode well for these alternative hypotheses of therapeutic efficacy.

Unfortunately, no form of curcumin, or its closely related analogues, appears to possess the properties required for a good drug candidate (chemical stability, high water solubility, potent and selective target activity, high bioavailability, broad tissue distribution, stable metabolism, and low toxicity). The in vitro interference properties of curcumin do, however, offer many traps that can trick unprepared researchers into misinterpreting the results of their investigations.

While such an analysis does not entirely preclude curcumin eventually being a useful remedy, it does reduce the likelihood of this, especially given the failure of any dramatic clinical trial results suggesting a significant real-world benefit.

Posted in Herbs and Supplements | 19 Comments

Evidence Update: Feline Facial Pheromone Doesn’t Reduce Stress or URIs in Shelter Cat Study

I have written numerous times about the use of pheromones to reduce stress and stress-related problems in cats and dogs (1, 2, 3). Overall, the evidence for these products is weak, and it is likely they have little to no meaningful benefit. A new study of pheromone therapy in shelter cats appears to support this conclusion.

Chadwin RM. Bain MJ. Kass PH. Effect of a synthetic feline facial pheromone product on stress scores and incidence of upper respiratory tract infection in shelter cats. J Am Vet Med Assoc. 2017 Aug 15;251(4):413-420.

In this study, several hundred shelter cats were exposed to a pheromone diffuser or a placebo diffuser and assessed in terms of behavioral indicators of stress and incidence of upper respiratory infections (URI), which appear to occur more commonly with increases stress.

The methodology was generally sound, with appropriate randomization, blind assessment, and placebo controls. The study was under-powered, which means it is possible that a small difference between the groups may have not been detected in the statistical analysis. The authors also performed a large number of statistical comparisons of many variables. This is an approach which can raise the risk of falsely positive findings.

The findings, however, were pretty consistently negative. No difference was seen in stress scores or in the occurrence of URI between cats exposed to the pheromone and those exposed to the placebo. No evidence of harm from the pheromone treatment was seen, though this was not specifically sought.

As usual, no single study should be taken as the definitive answer to any medical question. However, in light of the fact that pheromones have been in use and studied extensively for decades and strong, consistent evidence of significant benefits has not been seen, this study strengthens the argument that these products do not, in fact, provide such benefits.



Posted in Science-Based Veterinary Medicine | Leave a comment

Evidence Update: Potential Associations Between Neutering and Immune System Disorders

The risks and benefits associated with neutering are a complex and active area of research and debate in veterinary medicine. I have written several extensive summaries of the literature and numerous articles here evaluating the burgeoning research evidence. One subject that has seldom come up is the potential influence of neutering on the occurrence of diseases of the immune system. Although it is well established that sex hormones have variable and significant effects on the immune system, and that there are frequently sex differences in the risk of autoimmune and immune-mediated diseases, which suggests that sex hormones influence this risk, there has not been much direct research evaluating the relationship, if any, between neutering and the occurrence of diseases involving the immune system. A retrospective study published last year attempts to add to the very limited evidence previously published on this subject.

Sundberg CR. Belanger JM. Bannasch DL. et al. Gonadectomy effects on the risk of immune disorders in the dog: a retrospective study. BMC Veterinary research. 2016;12:278.

The authors looked back at a university veterinary college database of patients seen over a 15-year period. They first identified diagnoses of a number of conditions involving the immune system an then looked for differences in the occurrence of these conditions between males and females and between intact and neutered animals. The conditions evaluated included:

Atopic dermatitis (atopy or environmental allergies)
Autoimmune Hemolytic Anemia (AIHA)
Myasthenia gravis (CMG)
Hypoadrenocorticism (ADD or Addison’s disease)
Immune-mediated polyarthropathy (IMPA)
Immune-mediated thrombocytopenia (ITP)
Inflammatory bowel disease (IBD)
Lupus erythematosus (systemic SLE and discoid DLE)
Pempigus complex (PEMC)

These conditions were chosen because they all occurred in at least 0.1% of the dogs in the database. These are the most common of a group of conditions which are still, as a whole, usually very uncommon. The authors also looked at the occurrence of pyometra or uterine infections, a condition known to be common in intact females and to be prevented by neutering, which served as a control condition.

The study found an association between being neutered and the occurrence of 7/11 of the autoimmune diseases evaluated: ATOP, AIHA, ADD, HYPO, ITP, IBD, and LUP. Of these and increases occurrence of LUP was only seen for females, and for females appeared to be at greater risk than males for all of the conditions except ADD.

For those animals in which the age of neutering was known, no association was found between disease occurrence and age at neutering.

As expected, pyometra was significantly more common in intact females compare to neutered females.

While these data do suggest that there may be some protective effect of sex hormones against autoimmune disease, the authors correctly identify a number of important caveats:

  1. Retrospective studies are NEVER proof of a causal relationship because there are too many variables that cannot be identified or controlled.
  2. The study population at a university hospital is often very different from the population in general, which makes it unreliable to extrapolate associations from one to the other. For example, atopic dermatitis is one of the most common conditions seen in dogs with rates up to 19% reported. This study population only had a rate of 1.8%, which is much lower than expected. In general, university patients are much sicker and have more unusual conditions than typically seen in the general pet population, so they aren’t always good examples of health and disease in more normal populations.
  3. Even if there is some causal role of neutering in the occurrence of these conditions, it is not the only or primary cause. Genetic variables and environmental triggers have been identified for many of these conditions, so any role played by neutering is just one of multiple factors to consider in the genesis of these conditions.
  4. These conditions are mostly quite uncommon, and any increase in risk that might be associated with neutering has to be balanced against the established benefits of neutering to the health of individuals and to the pet population as a whole.

Bottom Line
This paper adds some useful information to the complex and ongoing assessment of the risks and benefits of neutering. It does not establish that neutering causes autoimmune disease, and it is not justification for dramatic changes in neutering practices. However, it support continued study and consideration of the potential negative effects of neutering on the immune system.

Posted in Science-Based Veterinary Medicine | 10 Comments

AVMA Policy Cautions Vets about Unproven Stem Cell Therapies

The American Veterinary Medical Association (AVMA) is the main professional organization for veterinarians in the United States. It is not a government or regulatory body, but it does sometimes promote policy statements or guidelines intended to encourage or discourage certain practices by veterinarians. In general, I have been disappointed in the unwillingness of the AVMA to confront the danger pseudoscience presents for veterinary patients, clients, and the integrity of our profession.

For example, despite the clear statement of its own Council on Research acknowledging that, “there is no clinical evidence to support the use of homeopathic remedies for treatment or prevention of diseases in domestic animals” the AVMA House of Delegates overwhelmingly rejected a resolution identifying homeopathy as an ineffective therapeutic intervention. This was a pure case of politics trumping science and of a political organization refusing to protect the public from quackery because doing so would discomfit part of its constituency.

Similarly, the AVMA House of Delegates admitted the American Holistic Veterinary Medicine Association (AHVMA), the most prominent advocacy organization for pseudoscientific medical practices, as a constituent organization in 2013. This was based solely on such criteria as having enough AHVMA members who were also AVMA members, and the move ignored the blatant promotion of pseudoscience and untested or clearly ineffective treatments that is the main reason for the AHVMA’s existence.

Given that the AVMA has not been very strong or consistent in promoting science-based standards for veterinary medicine, I was pleasantly surprised by the recent AVMA position statement on stem cell therapies. I have written about stem cell therapies frequently. It is a promising area of research that, unfortunately, has been promoted and put into widespread use far ahead of appropriate scientific evidence establishing safety and efficacy for particular methods and indications.

The FDA has essentially chosen not to exercise its regulatory authority over veterinary stem cell therapies so long as they involve cells taken from and given back to the same individual and are not used in food animals. As a result, many stem cell products are legally available that have never been properly tested to show they do more good than harm. I am quite optimistic about the potential for stem-cell-based therapies to provide useful therapeutic tools eventually, once appropriate research is done, but for now they are essentially an uncontrolled experiment on individual patients.

The AVMA, uncharacteristically, appears to largely agree with this position:

While regenerative medicine holds promise of improvements in the treatment of a variety of diseases, many of which lack adequately effective treatments, questions remain…While data continue to accumulate suggesting therapeutic benefit from regenerative medicine, published peer-reviewed studies definitively documenting benefit are still lacking for many diseases. Nor has a scientific consensus for stem cell type, stem cell origin, dosage, transfer media, or method of administration been developed for each disease being treated. Despite these scientific insufficiencies, the adoption of regenerative medicine in the veterinary profession has grown rapidly. Unfortunately, some therapies being propounded and the processes and equipment being sold have outpaced the science which supports them.

Of course, like any fundamentally political organization, the AVMA has to try to please everyone, even when that results in an internally inconsistent position. For example, the policy is quite clear about the importance of validating stem cell therapies with proper research evidence before utilizing them:

Regenerative therapy protocols should be formulated from evidence-based medicine. Veterinarians should refrain from recommending regenerative medicine protocols for which documented benefit has not been shown by clinical trials.

Regenerative therapies should utilize systems, equipment, and processes which have been adequately validated to produce therapeutic cell numbers, documented cell types, adequate cell viability, and sterility. The use of systems without such validation poses unnecessary risk to the patient, compromises treatment successes, impedes collection of therapeutic data, and exposes the attending veterinarian to potential liability.

Veterinarians engaged in the use of regenerative medicine and vendors of cell products, equipment, laboratory services, and processes should refrain from making claims in client communication, advertising, or websites that are not fully supported by peer-reviewed, published data.

Since no extant stem cell therapy can meet these criteria, effectively this should mean using stem cell treatments only as part of a clinical trial research or, perhaps, as a last-ditch treatment in desperate circumstances with full disclosure to clients that the treatment is untested and experimental. That, of course, is not at all how stem cell companies and veterinarians typically present these treatments. And the AVMA weakens its own policy by not being willing to directly discourage the use of such treatments by veterinarians. Throughout the policy it is assumed that veterinarians will continue to use these treatments despite the absence of the kind of evidence the AVMA suggests should be a prerequisite for their use:

The AVMA supports the continued scientific development of these modalities while at the same time encouraging its members to employ caution with respect to their use.

…it is incumbent upon veterinarians engaged in regenerative therapies to be well versed in the emerging science of the field in order to successfully select the specific therapeutic protocols, processes, equipment, and vendors most likely to result in clinical benefit for their patients.

Despite this equivocation, however, it is encouraging to see the AVMA clearly acknowledge that the evidence base is not yet sufficient to justify claims of safety and efficacy for veterinary stem cell therapies and that their use is not supported by adequate, appropriate science. Hopefully, this will lend some weight to the voices of caution in the profession trying to restrain the proliferation of stem cell therapies until we have sufficient reason to believe they are helpful and not harmful.


Posted in Science-Based Veterinary Medicine | 18 Comments

Evidence Update: Music and Anxiety in Dogs

It has become quite popular to recommend music as a method of reducing the stress and anxiety of dogs in environments likely to be stressful for them, such as veterinary hospitals and shelters. I’ve reviewed the evidence concerning the effects of music in dogs (1, 2), and in general it is intriguing but not yet very convincing. Some studies show some potential effects, others don’t. Most studies have a significant degree of subjectivity to their measures of effect, and there is little consistency to what music is used and how it is presented. Overall, it is unlikely that playing music in veterinary settings does any harm, but it is unclear whether it does any good.

A new study has recently been published which adds a bit of evidence to this debate.

Engler WJ. Bain M. Effect of different types of classical music played at a veterinary hospital on dog behavior and owner satisfaction. J Amer Vet Med Assoc. 2017;251(2);195-200.

This study looked at healthy dogs and those with non-urgent medical problems seen at the community practice service of a veterinary college. In brief, the study randomly assigned dogs to be examined in rooms with classical music, the same music modified by a private company that claims to make it more appealing or effective for dogs, and no music at all. Owners and veterinarians then evaluated the level of anxiety, anxiety-related behaviors, and aggression in the dogs. Obviously, the study was not blinded since everyone participating was aware of whether or not music was playing.

The study was clearly negative, finding no differences between the three groups in any measure of anxiety or aggression. This lack of difference between the treatment groups held for both subjective behavioral measures and for objective measures such as temperature and heart rate. The only statistically significant difference identified was that owners felt their dogs were less anxious in the examination room than in the waiting room (regardless of whether music was played) and that owners were more satisfied with their visit when the original classical music was played than with the modified music or no music at all.

Certainly, no single study is ever the last word on any complex medical subject, and while this was a well-designed experiment, like all clinical research it has limitations. Direct comparison with other studies is difficult due to the differences in music choice, study population, study conditions, and many other factors. Nevertheless, this study does weaken the already tentative and inconsistent support for significant anti-anxiety benefits in dogs from the playing of music in veterinary settings.

Of course, both owners and clinicians liked the classical music, which may be reason enough to play it in this type of setting. Reducing human anxiety and improving client satisfaction are appropriate goals for environmental manipulation in the veterinary clinic. And as the authors suggest, improvement in the anxiety of canine patients could possibly be achieved through reducing the anxiety of their owners, regardless of whether the music has any direct benefits to the canine patients. Still, it is important to recognize that such intervention may effect people in one way and dogs in another (or not at all), and we have to be wary of assuming our patients will benefit simply because we like it. We also have to be mindful of the caregiver placebo effect, especially with unblinded studies of interventions with subjectively measured effects.

There were a couple of other interesting tidbits in the paper. One unsurprising finding was that owners rated their dogs’ anxiety significantly higher than the veterinarians did. Owners obviously have a more personal stake in their dogs’ reactions to the veterinary environment and are likely more sensitive and negatively affected by signs of anxiety in their pets than veterinarians, who likely view a certain amount of anxiety as normal for the situation and not a cause for concern.

The paper also illustrated how difficult it is for researchers not to put the most positive possible spin on the results of their study. This was a well-designed and reported study, and the authors deserve great credit for publishing and fully reporting negative results. Negative studies are critical to an accurate, balanced understanding of the effect of treatments, yet they are often not published, due to bias on the part of researchers and journals. As a result, the literature often presents an inaccurately positive view of medical treatments.

In this paper though the data clearly showed no difference between any of the groups (and hence no effect of the music, except on owner satisfaction), the authors still began the discussion with the claim, “Results of the present study indicated that the playing of classical music in veterinary examination rooms had some positive effects on both dogs and their owners.” Anyone reading only the discussion section (as busy clinicians often do) would come away with the misconception that the study show benefits to music in terms of reduced anxiety even though it actually showed no effect at all.

Bottom Line
This paper adds a small piece of evidence to the overall subject of the effect of music on anxiety and behavior in dogs in the veterinary setting. The existing evidence is weak and inconsistent, so no clear conclusion can be drawn. In this study, there was no sign of any effect of classical music or the same music digitally altered with the goal of reducing stress in dogs. The question remains open, and definitive claims for or against the potential effects of music in this situation are not justified.


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