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FDA Warns Consumers About Unsupported Claims for Hyperbaric Oxygen Therapy

Posted on August 22, 2013 by skeptvet

I reviewed the evidence for Hyperbaric Oxygen Therapy (HBOT) recently after a series of conversations on a popular veterinary discussion forum (Veterinary Information Network: VIN) in which quite strong claims were put forward about the potential value of this therapy for pets. While HBOT is a plausible therapy for which there is some good evidence of benefit in specific situations, there are unfortunately many people promoting and selling this treatment with claims that go well beyond anything supported by real scientific evidence.

Such promotion has apparently become sufficiently extensive that the Food and Drug Administration (FDA) has come out with a new consumer warning emphasizing that HBOT is not approved or proven effective for most of the conditions for which it is advertized. This warning includes a specific, though not complete list of conditions for which HBOT has not been scientifically proven effective nor approved by the FDA. Several of these conditions were presented in the VIN discussions as being approved by the FDA, so I thought it would be useful to post the FDA statement here for clarification.

No, hyperbaric oxygen therapy (HBOT) has not been clinically proven to cure or be effective in the treatment of cancer, autism, or diabetes. But do a quick search on the Internet, and you’ll see all kinds of claims for these and other diseases for which the device has not been cleared or approved by FDA.

HBOT involves breathing oxygen in a pressurized chamber. The Food and Drug Administration (FDA) has cleared hyperbaric chambers for certain medical uses, such as treating decompression sickness suffered by divers.

HBOT has not, however, been proven to be the kind of universal treatment it has been touted to be on some Internet sites. FDA is concerned that some claims made by treatment centers using HBOT may give consumers a wrong impression that could ultimately endanger their health.

“Patients may incorrectly believe that these devices have been proven safe and effective for uses not cleared by FDA, which may cause them to delay or forgo proven medical therapies,” says Nayan Patel, a biomedical engineer in FDA’s Anesthesiology Devices Branch. “In doing so, they may experience a lack of improvement and/or worsening of their existing condition(s).”

Patients may be unaware that the safety and effectiveness of HBOT has not been established for these diseases and conditions, including:

AIDS/HIV

Alzheimer’s Disease

Asthma

Bell’s Palsy

Brain Injury

Cerebral Palsy

Depression

Heart Disease

Hepatitis

Migraine

Multiple Sclerosis

Parkinson’s Disease

Spinal Cord Injury

Sport’s Injury

Stroke

Patel says that FDA has received 27 complaints from consumers and health care professionals over the past three years about treatment centers promoting the hyperbaric chamber for uses not cleared by the agency.

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How HBOT Works

HBOT involves breathing oxygen in a pressurized chamber in which the atmospheric pressure is raised up to three times higher than normal. Under these conditions, your lungs can gather up to three times more oxygen than would be possible breathing oxygen at normal air pressure.

Patel explains that your body’s tissues need an adequate supply of oxygen to function. When tissue is injured, it may require more oxygen to heal. “Hyperbaric oxygen therapy increases the amount of oxygen dissolved in your blood,” says Patel. An increase in blood oxygen may improve oxygen delivery for vital tissue function to help fight infection or minimize injury.

Hyperbaric chambers are medical devices that require FDA clearance. FDA clearance of a device for a specific use means FDA has reviewed valid scientific evidence supporting that use and determined that the device is at least as safe and effective as another legally U.S.-marketed device.

Thirteen uses of a hyperbaric chamber for HBOT have been cleared by FDA. They include treatment of air or gas embolism (dangerous “bubbles” in the bloodstream that obstruct circulation), carbon monoxide poisoning, decompression sickness (often known by divers as “the bends”), and thermal burns (caused by heat or fire).

Posted in General, Science-Based Veterinary Medicine | 4 Comments

Evidence Update–Canine Cognitive Dysfunction

Posted on August 21, 2013 by skeptvet

Canine Cognitive Dysfunction (CCD) is a common and significant disease in older dogs which resembles, in many ways, some forms of dementia in humans. I have written about proposed therapies several times (1, 2, 3). Because there is no highly effective therapy for this disorder, it is a condition for which many unproven treatments are marketed based almost entirely on anecdotes or theoretical rationale. A new study adds a little to our understanding of this disease
Fast, R., Schütt, T., Toft, N., Møller, A. and Berendt, M. (2013), An Observational Study with Long-Term Follow-Up of Canine Cognitive Dysfunction: Clinical Characteristics, Survival, and Risk Factors. Journal of Veterinary Internal Medicine, 27: 822–829. doi: 10.1111/jvim.12109

The study involved evaluating geriatric dogs presenting to a general practice for routine care or minor health problems and classifying them as having CCD, borderline CCD, or no evidence of CCD based on a questionnaire. The dogs were characterized by symptoms, breed, and potential risk factors and then followed for 3 years to determine survival to this point.

The authors identified four primary clinical symptoms most consistently present in CCD dogs- sleeping during the day and restless at night, altered interaction, signs of disorientation at home, and anxiety. They did not find that eliminating indoors was a common symptom, which is important since this is often intolerable to owners and leads to considerations of euthanasia.

Interestingly, they did not find a difference in 3-year survival between dogs with and without CCD. The dogs with CCD received active therapy (selegilene, therapeutic diets, and behavioral stimulation), which might have had an impact on their outcome, though it isn’t possible to say from these data.

Finally, the authors evaluated Vitamin E levels in the different groups since it is often hypothesized that oxidative damage plays a role in the disease, and some prior studies have found decreased vitamin E levels in the brains of dogs and humans affected by dementia. In this study, however, no association between CCD and Vitamin E level was identified.

As is always the case, there are a number of limitations to this study, in particular the potential bias in how subjects were selected and the lack of systematic control for potential differences between subjects other than CCD. It is essentially a descriptive study, and as such provides some information about the characteristics of this population, but it cannot be used to draw definitive conclusions about the cause or treatment of CCD.

Posted in Science-Based Veterinary Medicine | 1 Comment

British Vets Denounce Homeopathy-But Refer Clients for it Anyway?

Posted on August 14, 2013 by skeptvet

This is a guest post from a colleague in the United Kingdom, Arlo Guthrie

As the editor of VetSurgeon.org, the leading online community for veterinary surgeons in the UK, I thought it would be interesting to assess British vets’ attitudes to homeopathy. So I joined forces with Alex Gough MA VetMB CertSAM CertVC MRCVS, Head of Medicine Referrals at Bath Veterinary Referrals to conduct a survey of our members.

The survey generated a response from 460 veterinary surgeons, which equates to about 2.4% of all 18,000 or so vets in the UK, including those that don’t work in general practice. So, a good sample size. First we asked whether respondents practised homeopathy themselves. 6.2% did, which means that there was some bias in favour of homeopaths (a survey carried out in 2006 found that 4.6% of British vets claimed complementary medicine as a speciality). We also asked whether homeopathy is routinely available to clients through the respondent’s practice. 7.7% said it was.

So to the first question to assess practitioners’ attitudes to homeopathy. We asked: ‘In your opinion, are there any veterinary medical conditions for which homeopathy could be an effective treatment? We deliberately couched this question in the broadest possible terms: ‘any’ and ‘could’. Despite this, a resounding 83.4% said ‘NO’.

In our next question, we sought to judge the depth of disbelief surrounding homeopathy. We asked: ‘Which would best describe your opinion of veterinary homeopathy?’. 77.4% answered ‘An ineffective form of veterinary medicine’. 9.5% said: ‘A rarely effective form of veterinary medicine’. 8.6% said: ‘An occasionally effective form of veterinary medicine’, and a paltry 4.5% said: ‘A reliably effective form of veterinary medicine’.

As a further indication of how strongly British practitioners believe that homeopathy is ineffective, 73% said that they believe that owners should sign a statement that they understand that in trials, homeopathy has been shown to be ineffective.

We also asked: ‘Do you feel it is appropriate for veterinary surgeons to practise homeopathy?’. 78.5% said ‘NO’.

All in all, a unequivocal result. Simply put, the overwhelming majority of British veterinary surgeons think homeopathy is wholly ineffective.

But how do they respond when asked by a client to refer a pet for homeopathy? In our survey, 24.3% of respondents said they would refer to a homeopath. A further 33.8% said they would explain that homeopathy does not work, but refer the case anyway. So that’s nearly 60% that would be prepared to refer, despite the majority believing that homeopathy is completely ineffective. 17.6% said they would explain that homeopathy does not work, and that the client will need to self-refer. 24.3% said they would explain that homeopathy does not work, and recommend the client does not self refer.

There are a number of possible hypotheses as to why vets may be prepared to refer clients for homeopathy, including a belief that they may retain some measure of control over the case, a fear of alienating the client, and the oft-stated argument that ‘it’s water, it’ll do no harm’.

We would argue that it’s the bigger picture that general practitioners need to consider; that the very act of referring endows homeopathy with a cloak of respectability which is simply not supported by science (on the contrary, it would require that we dismiss most of the proven laws of physics and chemistry).

It’s estimated that over £40M is spent on homeopathy annually in the UK, including £4M by the National Health Service. The sooner that more veterinary surgeons and their colleagues in human medicine are prepared to join the 24% of vets that refuse to endorse homeopathy, the sooner this money could be spent on effective methods of relieving suffering, both human and animal.

Posted in Guest Posts, Homeopathy | 93 Comments

The Marketing of Veterinary Homeopathy

Posted on August 7, 2013 by skeptvet

There has been quite a bit of public discussion and debate about veterinary homeopathy this year. This is due in large part to the Connecticut Veterinary Medical Association (CVMA) resolution presented to the American Veterinary Medical Association (AVMA) House of Delegates identifying homeopathy as an ineffective and unscientific therapy. Though the resolution was ultimately relegated to “consideration” by a committee unlikely to act on it in any substantive way, it did expose the overwhelming evidence that homeopathy is nothing more than a placebo. The resolution also stimulated a vigorous, often highly emotional response from supporters of homeopathy, and several complex but ultimately unconvincing attempts to present homeopathy as scientifically valid and legitimate.

A key organization involved in promoting and defending homeopathy is the Academy of Veterinary Homeopathy (AVH). I have written about them several times in the past, including a detailed look at their recommended Standards of Practice and coverage of the AVH lawsuit against the American Association of Veterinary State Boards (AAVSB) attempting to force recognition of their continuing education courses when the AAVSB ruled they did not meet acceptable scientific standards. The most recent issue of the Journal of the Academy of Veterinary Homeopathy provides some useful insights into how the members of this organization think and how they plan to continue promoting this discredited therapeutic approach.

As I have discussed before, proponents of alternative therapies generally, including homeopaths, tend to rely heavily on case reports as supporting evidence. Case reports are simply structure, published anecdotes, and while they are useful for suggesting hypotheses to test, they prove absolutely nothing. They are no more reliable than any other medical miracle story.

Yet the AVH goes so far as to call their annual meeting “The AVH Annual Case Conference,” and the journal reports almost exclusively anecdotes and no formal, controlled studies. Though there are controlled clinical trials done to investigate homeopathy (which, when looked at carefully, do not support any real effects), homeopaths still rely on uncontrolled individual observation as the core type of evidence both to validate specific homeopathic interventions and to guide the development of the discipline. This is fundamentally inconsistent with scientific and evidence-based medicine, which recognizes the low reliability and high risk of bias associated with such evidence.

Many of the case reports share some common elements:

There is no objectively confirmed definitive diagnosis.
Conventional therapy (whether appropriate or inappropriate) is identified as having failed.
Conventional medical practices are frequently implied to have caused or worsened the problem.
Homeopathy is claimed, or implied to have cured the problem.

All of these cases are therefore emotionally compelling arguments against conventional medicine and for homeopathy which, unfortunately, include absolutely no control for bias or error and actually prove nothing. This is marketing, or perhaps more accurately proselytizing, masquerading as science.

Here are a couple of examples:

a three-year-old miniature stallion…presented with acute and persistent seizure activity which occurred a week after a rabies vaccination coupled with a very traumatic tooth floating experience. The complementing video clips clearly demonstrated the symptoms, patient care and the progression to full recovery!

a two-year FS, mixed breed dog presented after an array of suppressive and intensive therapy (including a ligated carotid artery) for a chronic purulent and bloody nasal discharge. Once every(!) diagnostic and therapeutic technique had been tried, [the owner] turned to homeopathy. [The homeopath], using Aurum, guided [the pet] and her guardian through the re-emergence and eventual clearing of suppressed skin, emotional, digestive and nasal symptoms.

A family crisis results in a serious symptom emerging [in a MN DSH]: a suspected nasal squamous cell carcinoma…Gradual, ascending potencies (along with nutritional support from CoQ10, Standard Process Cataplex ACP and Feline Immune Support) resolved all symptoms. Since the last remedy, he has remained well for over a year. [This illustrates] Aphorism 17 regarding cure: “through taking away the entire complex of perceptible signs and befallments of a disease, the internal alteration of the life force which is lying at its base (consequently the totality of the disease) is simultaneously lifted.”

one of her patients was sent home to die in an anemic almost comatose state after diagnosis with inoperable bleeding tumors. Her courage and patience in prescribing assisted this very fragile individual to make what so far is a complete and miraculous recovery.

Apart from a misleading emphasis on uncontrolled anecdotes, the AVH journal illustrates the inconsistent attitude of the veterinary homeopathy community towards science and the disingenuous use of scientific research as a marketing tool.

Dr. Shelley Epstein is one of the most prominent homeopaths claiming that homeopathy is a proven and scientifically legitimate field. I have responded to her arguments in detail before (The Science of Homeopathy?, The Evidence for Homeopathy-A Close Look). Essentially, she simultaneously claims that randomized clinical trials support the efficacy of homeopathy (referring primarily to poor quality positive trials with high risk of bias and completely ignoring better quality negative trials and the systematic reviews of the literature which show no convincing evidence of a clinically measurable effect beyond placebo) and argues that typical RCT design is inappropriate to apply to “individualized” homeopathic therapy.

In this issue of the AVH journal, Dr. Epstein is reported as continuing to assert that there is consistent and reliable evidence for the mechanism and benefits of homeopathy, despite the lack of acceptance of this evidence by anyone in the scientific community, apart from practitioners of alternative therapies:

We have moved well beyond whether homeopathy can be measured, into being able to measure nanoparticle quality control issues among the starting homeopathic products; measure specific frequency differences between remedies and their potencies; measure variation in particle and aggregate size and shape; and measure elemental composition of the homeopathic particles. Studies are finding out how nanoparticles remain dispersed in solution via the hypotheses that trituration generates nanofraction formation, lactose acts as stabilizer to prevent aggregation, dilution allows larger raw particles to settle out and nano-clusters to disperse freely in the medium. Other research involves remedies as nanomedicines and how their dissolved silicate structures carry remedy information into the body.

I have discussed the subject of “nanoparticles” as a validation of homeopathy elsewhere. I have also previously addresses the subject of “hormesis,” which Dr. Epstein also attempts to stretch from a narrow scientific phenomenon having nothing to do with homeopathy into some kind of scientific validation of homeopathic principles. Such misuse of nanoparticle physics, quantum physics, and other obscure but legitimate scientific fields is a hallmark of pseudoscientific rationalizations of alternative therapies.

However, even more dramatic examples of pseudoscience taken seriously are available in the AVH journal.

One speaker openly discusses the true nature of homeopathy as a form of spiritual healing, a religious belief rather than an approach to medicine compatible with science:

Let’s look at Aphorism11 of the Organon:”…initially only the spirit-like, autonomic life force…is mistuned… Only the life principle…can induce in the organism the irregular functions that we call disease.” We know this, but it is still easy to get lost in the perceptions of material agents as causes of disease. When we use vision in homeopathy, it is not to observe the causal agent but to perceive the effects of this disturbance of the life force….Homeopathy is right in the mix with a growing evidence base to show that homeopathic preparations can affect gene expression. While gene expression is in the physical realm, it can be altered via an energetic medicine.

And in his presentation, the legendary veterinary homeopath Richard Pitcairn

continues to stretch our perceptions of time and reality. Thought provoking indeed was the discussion of multiple personalities. Some with individual disease processes were definitely confounding. In one personality there would be a documented severe eye injury which would completely and instantly disappear as he shifted to his other personality….Some multiples changed eye colors between the personalities.

How the AVH can simultaneous claim scientific legitimacy and promote nonsense like this is truly mysterious. However, the AVH appears to recognize that homeopathy has an image problem (though not that this problem is that too many vets recognize it for the pseudoscience that it is). The journal editor speaks directly to this subject:

holistic or CAVM or integrative veterinary medicine is taking a more prominent role. With that increased visibility and scrutiny comes the need to act and practice responsibly. We have often been viewed as the insurgents in veterinary medicine and…it behooves us to present ourselves in a more conventionally professional way. I think we need to be aware that every column we write, every blog we post or forum letter we write can have a far-reaching impact. This is doubly true if we are venting or criticizing colleagues, organizations or disciplines.

I certainly support respectful, substantive disagreement within the veterinary profession, and I have often been disturbed by the extreme, sometimes religious zeal with which proponents of alternative therapies sometimes respond to quite polite and evidence-based critiques of their methods. For example, one prominent supporter of homeopathy responded to the CVMA resolution presented to the AVMA by linking it to the Holocaust. Another once responded to a post of mine criticizing the American Holistic Veterinary Medical Association (AHVMA) by calling me a “shill for the pharmaceutical companies” and claiming that “threatened financially and ideologically, [he] must resort to political tactics of attack, shock and awe using headlines inspired by the National Inquirer or some other ladies gossip rag.”

To be fair, I too have sometimes been guilty of letting my emotions get the better of me and expressing my objections to specific practices in an excessively personal and inflammatory way, especially in the early days of blogging about the subject. However, I think it is a greater problem that healthy debate about the merits of alternative therapies is often impossible due to the passionate hostility that often greets any criticism of such approaches. It would be better for our profession if we could keep our disagreements civil and focused on ideas and evidence.

Unfortunately, I suspect this call for a more thoughtful tone in responding to critics of homeopathy may be more about perception and public relations than a true desire for substantive and respectful engagement. This suspicion is heightened by the announcement in the AVH journal that,

The AVH has hired a public relations representative. Peter Gold has experience working with the National Center for Homeopathy (NCH) and other organizations. Our goals are to increase awareness about homeopathy, build membership and raise funds for AVH.Your contributions (case testimonials, anecdotes, homeopathy tips etc.) are also needed….

AVH is blessed to have marketing director Peter Gold, who has been very helpful promoting AVH and homeopathy. His latest accomplishment was establishing a connection with Dogs Naturally magazine. I’d like to give everyone a gentle push to submit your success stories to Peter and the magazine. This is an excellent opportunity to get the word out about homeopathy.

The summer issue of the AVH journal also provides an update on the AVH lawsuit against the AAVSB. The AVH lost their case at every level, including a final failure on appeal to the Virginia State Supreme Court. However, they still consider it a worthwhile effort:

There was speculation that perhaps the AVH’s stand against AAVSB may have been the instigation for much of the current interest in homeopathy, reorganization of the holistic review committee of RACE and the impetus for other similar suits from holistic veterinary organizations.it was well worth the fight and achieved some worthy goals.

It is telling that the AVH has a legal advisor who has helped them pursue a 4-year lawsuit and now a marketing and public relations advisor, both employed to promote homeopathy by means other than rigorous scientific research. This illustrates the purpose of this organization, which is to function as an advocacy and marketing agency and a support group for practitioners of homeopathy, not as a scientific “academy” investigating homeopathy in an objective way. Homeopathy is a faith-based system in which scientific evidence is never a reason to question or reject existing dogma. The selective use of research findings by the AVH is not about discovering the truth but about developing marketing tools to create the impression of scientific validity.

There’s nothing inherently wrong with promoting a practice one believes in, of course. It is simply worthwhile for anyone evaluating the claims or evidence put forward by the AVH and its members to be aware that the organization is not interested in questioning or investigating the dogma of homeopathy in any objective way, and that scientific evidence is only employed by this group as a marketing tool, not as an impartial guide to what is true or false. While the group may claim that science supports homeopathy, this claim is inconsistent with

The AVH’s promotion of blatant mysticism and pseudoscience such as illustrated by this journal
The AVH’s use of litigation and public relations efforts to gain acceptance for a practice that cannot be effectively promoted on the basis of its scientific merits
The selective and biased use of scientific research to promote an unshakable belief rather than to identify effective and ineffective therapies.

The AVH purports to represent the mainstream beliefs and attitudes of veterinary homeopaths. If this is true, then there is no better illustration of why homeopathy as a discipline is inconsistent with science and should not be viewed as a legitimate veterinary therapy. The scientific evidence is clear and consistent that homeopathy is nothing more than a placebo, and all the litigation and public relations spin the AVH generates can do nothing to alter this.

Posted in Homeopathy | 16 Comments

Benefits and Risks of Neutering, An Evidence Update: Age at Neutering and Risk of Obesity

Posted on August 5, 2013 by skeptvet

This is another in my series of evidence updates on the risks and benefits of neutering in dogs and cats. I will be updating the evidence and conclusions of my original 2010 review as relevant new findings become available. This update concerns risk of being overweight or obese, which is one of the most common medical problems faced by veterinary patients.

Lefebvre, SL. Yang, M. Wang, M. Elliott, DA. Buff, PR. Lund, EM. Effect of age at gonadectomy on the probability of dogs becoming overweight. Journal of the American Veterinary Medical Association. 2013;243(2):236-43.

Objective-To determine whether gonadectomy or age at gonadectomy was associated with the risk that dogs would subsequently become overweight.

Design-Retrospective cohort study. Animals-1,930 dogs gonadectomized between 1998 and 2001 at ? 6 months of age (n = 782), > 6 months to ? 1 year of age (861), or > 1 to ? 5 years of age (287) and 1,669 sexually intact dogs.

Procedures-Dogs were followed-up through medical records for ? 10 years or until a diagnosis of overweight (defined as overweight, obese, or having a body condition score ? 4/5) was recorded. Information extracted included age at study entry, sex, breed, breed-size category, hospital visit frequency, and diagnosis (yes or no) of overweight or diseases that might affect body condition. Relative risk of a diagnosis of overweight was assessed among age groups of gonadectomized dogs and between gonadectomized and sexually intact dogs.

Results-No difference was detected among dogs grouped according to age at gonadectomy with respect to the risk of being overweight. This risk was significantly greater in gonadectomized dogs than in sexually intact dogs, but only during the first 2 years after gonadectomy. Sexually intact male dogs were approximately 40% less likely to have this diagnosis (hazard ratio, 0.61; 95% confidence interval, 0.52 to 0.72) than were sexually intact female dogs; no difference in risk between the sexes was evident for gonadectomized dogs.

Conclusions and Clinical Relevance-Gonadectomized dogs had a greater risk of being overweight than did sexually intact dogs, but this risk was not influenced by age at gonadectomy

Previous research discussed in my original review has indicated that neutered animals are at greater risk of becoming overweight than intact animals. Interestingly, there is some indication that this is not due to a change in the calorie needs or activity or neutered animals but possibly a change in the satiety mechanism, the system which tells an animal when it is no longer hungry. Neutered animals appear to eat more after neutering, which leads to weight gain. In any case, regardless of the true mechanism, the weight gain associated with neutering can be avoided by proper restriction of the calories fed to our pets.

What has been less clear is whether the age of neutering influences the risk of obesity. This study has added some evidence to help answer that question, and the results appear to show that there is no effect of the age of neutering on the obesity risk.

There are a number of limitations in the conclusions we can draw from retrospective studies in general, and from the particular data set used here, and the authors discuss some of these in the paper. Overall, however, this study provides yet another bit of useful data to help inform neutering decisions. If there are compelling reasons to neuter early (less than 6 months of age), as is often the case for unowned animals in shelters, we can be fairly confident that this will not greatly increase the risk of later obesity so long as the dogs are appropriately fed.

A somewhat surprising finding was that neutered animals appeared to be less likely to be diagnosed with osteoarthritis than intact dogs. Even more surprisingly, dogs diagnosed with arthritis in the study were less likely to be diagnosed as overweight. These findings contradict the usual understanding that obesity can predispose to osteoarthritis and that arthritis can reduce activity and possible worsen obesity. However, due to a number of methodological limitations, it is not possible to say if there is truly an increased risk of arthritis in intact dogs or, if so, why that might be. This provides an interesting question for further research, but not a reason to change current neutering practices.

Posted in Science-Based Veterinary Medicine | 5 Comments

Brain Protection Blend: Can Nutritional Supplements Preserve or Improve Cognitive Function in Cats?

Posted on July 18, 2013 by skeptvet

Age-associated Cognitive Dysfunction
As our pets age, behavioral changes associated with aging of the brain often become evident. Cats and dogs may exhibit changes in sleep patterns, in interactions with other animals or with humans, problems with housetraining, and other symptoms. These changes have been correlated with changes in the brain that appear similar to those seen in human who exhibit signs of Alzheimer’s or other forms of dementia, and it is believed that some of the same mechanisms may lead to the age-associated behaviors seen in our pets.

Once the symptoms reach a sufficient level of severity, and if we have ruled out other detectable medical problems that can affect behavior, we can tentatively classify individual animals as having cognitive dysfunction. There is not established preventative for this syndrome, and the only licensed therapy, a medication called selegiline, is not widely viewed as very effective. So research is ongoing to learn more about the causes of cognitive dysfunction in pets and to develop interventions to prevent or treat it. Many products are also on the market claiming to have some preventative or therapeutic benefit, but as I have discussed in previous articles, there is not robust evidence for any particular approach. (1, 2, 3)

I recently ran across a research article looking at another combination of nutritional supplements intended to have an effect of age-associated cognitive dysfunction, and I thought this would be a good opportunity to revisit the subject.

The Study
Yuanlong Pan, Joseph A. Araujo, Joey Burrows, Christina de River, Asa Gore, Sandeep Bhatnagar and Norton W. Milgram. Cognitive enhancement in middle-aged and old cats with dietary supplementation with a nutrient blend containing fish oil, B vitamins,antioxidants and arginine. British Journal of Nutrition (2013), 110, 40–49.

The authors present the combination supplement they are investigating as a potential preventative for age-associated cognitive decline, arguing that given the multiple pathologies of the aging brain a single substance is unlikely to have a significant effect. The specific ingredients were chosen on the basis of theoretical arguments about the proposed mechanism for pathologic changes in the brain with aging and experimental or epidemiologic evidence, primarily in humans, suggesting the particular ingredients might have value.

We have consequently developed a blend of nutrients, referred to as the brain protection blend (BPB), which were selected based on their ability to minimise [sic] or eliminate the risk factors associated with brain ageing and dementia. The BPB includes fish oil, arginine, B vitamins and selected antioxidants. Fish oil containing DHA and EPA was selected to prevent and correct DHA deficiency and offer anti-inflammatory benefits. Arginine was selected to enhance NO synthesis, which has been linked to circulation, blood pressure control and cognition. B vitamins prevent and correct any B vitamin deficiency and minimise [sic] the risk of high homocysteine. Antioxidants, including vitamins E and C and Se, offer protection against oxidative damage and inflammation-induced damage in both brain tissue and blood vessels.

The rationale for choosing these ingredients is reasonable, though as I will discuss below there is not strong evidence of actual clinically meaningful effects for any of them in any species.

The design of the study involved two groups of cats (16 in each) who were fed identical diets except for the “brain protection blend” given to one group. The cats were studies over a period of about 7-11 months, and a number of behavioral tests were administered at different time points. The groups were constituted in such a way that baseline performance on one of the tests, and overall experience with the testing method, were evenly distributed between groups. Though this is a pretty small sample size, the methodology was generally sound and the long duration of the study was a strength.

Of the cognitive tests administered, only one was given at the beginning and again at the end of the study. The others were only given once, which makes it impossible to assess whether the supplement prevented a decline in performance compared to the control group. It is unclear why the investigators conducted the study this way when they seemed to be suggesting that their major hypothesis was that the supplement would prevent loss of cognitive function with aging.

The authors also measured some proxy markers for the effect of the specific components of the supplement. For example they measured vitamin B12, folic acid, fatty acids composition of red blood cells, and total antioxidant activity, each of which would be expected to be influenced by the supplement used.

The Results
The results did show some difference in behavior between the groups on three of the four tests used. For the one test that was given twice, both groups actually improved in performance. The control group showed a 2.8% improvement, which was not statistically significant, while the treatment group showed a 10.4% improvement, which was.

The biochemical measurements showed that the fish oil supplementation did increase the levels of n-3 fatty acids and decrease the level of n-6 fatty acids as expected. Folic acid levels were also slightly higher in the treatment group at the end of the study. There was, however, no change in B12 levels or total antioxidant status in either group. And neither group showed any deficiency in any measured nutrient.

Existing Evidence for the Supplement Components
As I said earlier, the choice of specific ingredients was based on some existing evidence, however there isn’t a very strong case that any of these components have a clinically meaningful effect on cognitive function in humans or animals.

For B vitamins, recent reviews have found that deficiency status is associated with a risk of lower cognitive function in humans in some studies. However, this effect is not consistent in all studies, and it does not appear that B12 levels are associated with dementia in individuals without a measurable B12 deficiency or that B12 supplementation is beneficial in individuals with adequate B12 levels to begin with. The relationship between B12 deficiency and cognitive dysfunction is also influenced by genetic variables in the human studies that have not been assessed in cats. So as is often the case, a vitamin deficiency clearly has negative effects, but that doesn’t automatically mean that supplementation above normal levels has benefits. In this study, the cats were not B12 deficient, so a benefit from additional supplementation would not be expected based on extrapolation from the data in humans.(4, 5, 6)

For fish oils, the most recent Cochrane review of the literature in humans concluded, “Direct evidence on the effect of omega?3 PUFA on incident dementia is lacking. The available trials showed no benefit of omega?3 PUFA supplementation on cognitive function in cognitively healthy older people.”(7) Another review focusing specifically on Alzheimer’s also found little evidence of benefit from fish oil supplementation. (8) However, one review focusing on a specific kind of cognitive dysfunction, vascular dementia, did find some indication in the human research of a benefit to fatty acid supplementation. (9) So while this study showed that supplementation did affect the levels of different kinds of fatty acids in the cats, it isn’t clear whether or not this should be expected to have a clinically meaningful effect on brain function in this population.

Human studies have also been done looking at the effect of antioxidant vitamins on cognitive dysfunction in humans. There is some evidence of benefit of Vitamins C and E for reducing the risk of vascular dementia and Alzheimer’s (8, 9) A review of selenium and Alzheimer’s, however, showed no therapeutic benefit and only a theoretical suggestion that the supplement could have preventative benefits. (10)

What Does This Study Show?
The current study did find some differences in performance on cognitive function tests between cats who were fed the supplement and cats who were not. However, there are a number of limitations to our ability to extrapolate from these results to the use of such a supplement in prevention or treatment of cognitive dysfunction.

For one thing, the results of cognitive function tests might or might not reflect any effect on real-world behavior. It isn’t entirely clear that differences on these kinds of laboratory exercises predict benefits in terms of real-life function that would be noticeable to cat owners. Only a study of cats with naturally occurring clinical disease, or a large long-term study looking for differences in the chances of developing such disease, can really tell us if this sort of supplement would be useful in the real world.

It is also not entirely clear what relevance most of the tests have to the main goal of the study, showing that the supplement could potentially prevent age-associated decline in brain function. Since most tests were only administered once, they can’t be used to show a protective benefit. And for the one test done twice, both groups actually improved in function. While the treatment group improved more than the control group, which might indicate some effect of the treatment, neither showed evidence of cognitive decline.

The authors chose to interpret the differences seen as indicating a possible enhancement of cognitive function. This is certainly a possible explanation of the data, though there are reasons why this can only be a tentative conclusion. However, in terms of treating or preventing cognitive dysfunction associated with age, this study can’t provide any direct evidence since it isn’t clear there was any such dysfunction in these cats.

Another possible source of error appeared in the way the cognitive function test data was analyzed. The original intent was to include a failure to respond during a test as a contribution to the error rate for that subject. However, the rate of failure to respond was higher than expected and would have significantly impacted the outcome of several tests. As a result, the authors changed their method of calculating the error rate after the fact, and they ignored response failures. In some cases individual subjects were excluded entirely from the data for specific tests because of failing to respond. The authors mention that five such exclusions were necessary for the treatment group. It isn’t clear from the report if any individuals from the control group were excluded from the analysis for this reason.

This is important because changing the way the main outcome measure is determined after the test has been done introducing a significant risk of bias into any study. And if the subjects who failed to respond were predominantly from the treatment group, this could change the direction of the different in test scores and completely alter the conclusions of the study. While there is no way to know if this is actually the case, this does raise a significant question about the internal validity of these data.

In terms of the biochemical data, it did show that the supplement had the desired effect on fatty acid levels. However, there was no sign of any vitamin deficiency in any of the subjects, so based on the data in humans it is not clear that additional supplementation of B, C, and E vitamins would be likely to have any benefits. And in any case, the blood testing did not show any difference in B12 levels or in total antioxidant status, so it is not clear that these components of the supplement even had any effect at all on the actual levels of these substances in the subjects.

Are There Risks?
As always, there is little chance of an intervention of any kind in medicine having dramatic benefits with no risks. The evidence from human studies suggests most of the ingredients in this supplement had few side effects. Previous studies have found some risks associated with supplementation of Vitamin E and Selenium, including possibly increased risk of some cancers. On the whole, it is likely that the particular supplement studied in this investigation has few clinically significant risks.

Bottom Line
Cognitive dysfunction associated with ageing is a significant problem for companion animals, and it appears to have some clinical and biological features similar to some kinds of dementia in humans. There is limited evidence in humans that some nutritional supplements can have benefits in terms of preserving or improving cognitive function, however the data are weak and inconsistent, and often the effect depends on existing deficiency, genetic constitution, and other specific factors. The idea that nutritional supplements might help prevent or treat cognitive dysfunction in cats and dogs is reasonable, but there is little evidence to support the use of any particular supplement, and not much is known about the details of which nutrients might benefit individuals with particular causes of cognitive dysfunction.

The current study provides some support for the hypothesis that some of the nutrients investigated might have some effect on cognitive function in cats. However, the design generally does not allow any conclusion about the prevention or treatment of age-associated cognitive declines since it is not clear if any of the cats had this disorder or if there was deterioration in the control cats not experienced by the cats given the supplement. It is possible that the supplement improved the cats’ ability on some of the tests given in the study, but additional studies accounting for some of the limitations in this project would need to be done to confirm this.

Overall, then, there is little reason to believe that any specific supplement or combination will have dramatic benefits for all or most individuals with age-associated cognitive dysfunction. It may be that some causes of this syndrome can be mitigated by supplements and that this could result in clinically meaningful benefits, however this remains to be demonstrated.

Posted in Herbs and Supplements | Leave a comment

Chiropractic for Ducks: Yes, That’s Really What I Said!

Posted on July 11, 2013 by skeptvet

I’ve written extensively about the use of chiropractic in animals as well as humans. The bottom line is that the underlying theory is nonsense, and at best the evidence suggests it might offer some benefit for people with back pain, though no more than conventional therapy. This is hardly enough to balance the completely bogus claims for chiropractic therapy, the dangers of neck manipulation, and the nonsense like colonic irrigation and opposition to vaccines so often offered by chiropractors alongside back manipulation.

There is no convincing evidence that the therapy is beneficial for veterinary patients, and it is bizarre that chiropractors claim the problems animals experience, and the therapy they offer, are the same as for humans when the spinal anatomy of human beings is so dramatically different from most other species. Even if chiropractic manipulation of a persons back relieves pain, what possible relevance could this have to twisting a dog’s neck to treat seizures and neurologic problems or chronic internal medicine disorders, as claimed by the American Veterinary Chiropractic Association?

An illustration of the extent to which chiropractors practicing on animals so readily leave reality behind is the video below showing chiropractic manipulation of the neck of an injured duck. For the most part, critics of chiropractic are posting this as a joke, with lots of remarks about “quacks.” The problem is that the humor is diminished for me by the cruelty. Taking a frightened wild animal that has been hit by a car and subjecting it to cervical spinal manipulations for which there is not the slightest rational justification is ultimately a form of animal cruelty. It is a far cry from treating a consenting adult human being with back pain, and it illustrates why irrational approaches to medicine not supported by real evidence are not just silly or harmless. Once we head down the rabbit hole and suspend our skepticism and reliance on scientific evidence, we can quickly go from the merely unproven or unlikely to the outright crazy.

Posted in Chiropractic | 39 Comments

The Veterinary Evidence-Based Medicine Landscape

Posted on July 10, 2013 by skeptvet

This is a presentation I gave in London in 2012 at a conference sponsored by the Royal College of Veterinary Surgeons.

The Sceptical Vet: Evidence or Eminence?

This is the slide deck:

EBVM Landscape & Perspective

And this is a recording of the session.

Posted in Presentations, Lectures, Publications & Interviews | 1 Comment

The Three Most Dangerous Words in Medicine

Posted on July 10, 2013 by skeptvet

A brief look at why individual uncontrolled observations are often unreliable. This was my opening statement in a debate at the 2012 Annual Convention of the AVMA on the subject of “Which is Better: Clinical Trials or Clinical Intuition?”