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Dietary supplements are touted for cognitive protection, but supporting evidence is mixed. COSMOS-Mind tested whether daily administration of cocoa extract (containing 500 mg/day flavanols) versus placebo and a commercial multivitamin-mineral (MVM) versus placebo improved cognition in older women and men.

COSMOS-Mind, a large randomized two-by-two factorial 3-year trial, assessed cognition by telephone at baseline and annually. The primary outcome was a global cognition composite formed from mean standardized (z) scores (relative to baseline) from individual tests, including the Telephone Interview of Cognitive Status, Word List and Story Recall, Oral Trail-Making, Verbal Fluency, Number Span, and Digit Ordering. Using intention-to-treat, the primary endpoint was change in this composite with 3 years of cocoa extract use. The pre-specified secondary endpoint was change in the composite with 3 years of MVM supplementation. Treatment effects were also examined for executive function and memory composite scores, and in pre-specified subgroups at higher risk for cognitive decline.

A total of 2262 participants were enrolled (mean age = 73y; 60% women; 89% non-Hispanic White), and 92% completed the baseline and at least one annual assessment. Cocoa extract had no effect on global cognition (mean z-score = 0.03, 95% CI: -0.02 to 0.08; P = .28). Daily MVM supplementation, relative to placebo, resulted in a statistically significant benefit on global cognition (mean z = 0.07, 95% CI 0.02 to 0.12; P = .007), and this effect was most pronounced in participants with a history of cardiovascular disease (no history: 0.06, 95% CI 0.01 to 0.11; history: 0.14, 95% CI -0.02 to 0.31; interaction, nominal P = .01). Multivitamin-mineral benefits were also observed for memory and executive function. The cocoa extract by MVM group interaction was not significant for any of the cognitive composites.

The authors concluded that the Cocoa extract did not benefit cognition. However, COSMOS-Mind provides the first evidence from a large, long-term, pragmatic trial to support the potential efficacy of a MVM to improve cognition in older adults. Additional work is needed to confirm these findings in a more diverse cohort and to identify mechanisms to account for MVM effects.

This trial certainly has a few stunning features. For instance, its sample size was impressive and its follow-up period long. But it also has a few weak points. The study was conducted remotely via mail or telephone which means that compliance was impossible to control. Moreover, the outcome measures were subjective, and blinding was not checked. In addition, I fail to see a plausible mechanism of action. Most importantly, the generalizability of the results to the population at large seems questionable. It might make sense that older individuals many of whom might have low vitamin levels can profit from MVM. Whether this is also true for younger people who are well-nourished might be a different matter.

Even though most people do not think about it in this way, tea is a herbal remedy. We know that it is pleasant, but is it also effective?

This study explored the associations between tea drinking and the incident risk of type 2 diabetes mellitus(T2 DM). A dynamic prospective cohort study among a total of 27 841 diabetes-free permanent adult residents randomly selected from 2, 6, and 7 rural communities between 2006-2008, 2011-2012, and 2013-2014, respectively. Questionnaire survey, physical examination, and laboratory test were carried out among the participants. In 2018, the researchers conducted a follow-up through the electronic health records of residents. Cox regression models were applied to explore the association between tea drinking and the incident risk of T2 DM and estimate the hazard ratio(HR), and its 95%CI.

Among the 27 841 rural community residents in Deqing County, 10 726(39%) were tea drinkers, 8215 (77%) of which were green tea drinkers. A total of 883 new T2 DM incidents were identified until December 31, 2018, and the incidence density was 4.43 per 1000 person-years (PYs). The incidence density was 4.07/1000 PYs in those with tea drinking habits and 4.71/1000 PYs in those without tea drinking habits. The incidence density was 3.79/1000 PYs in those with green tea drinking habits. After controlling for sex, age, education, farming, smoking, alcohol consumption, dietary preference, body mass index, hypertension, impaired fasting glucose, and family history of diabetes, the risk of T2 DM among rural residents with tea drinking habits was 0.79 times higher than that among residents without tea drinking habits(HR=0.79, 95%CI 0.65-0.96), and the risk of T2 DM among residents with green tea drinking habits was 0.72 times higher than that among residents without tea drinking habits(HR=0.72, 95%CI 0.58-0.89). No significant associations were found between other kinds of tea and the risk of T2 DM, nor the amount of green tea-drinking.

The authors concluded that drinking green tea may reduce the risk of T2 DM among adult population in rural China.

Epidemiological studies of this nature resemble big fishing expeditions that can bring up all sorts of rubbish and – if lucky – also some fish. The question thus is whether this study identified an interesting association or just some odd rubbish.

A quick look into Medline seems to suggest great caution. Here are the conclusions from a few further case-control studies:

Thus the question of whether tea drinking might prevent diabetes remains open, in my view.

Yet, the paper might teach us two important lessons:

  1. Case-control studies must be taken with a pinch of salt.
  2. Correlation is not the same as causation.

As numerous of my posts have demonstrated, chiropractic manipulations can cause severe adverse effects, including deaths. Several hundred have been documented in the medical literature. When discussing this fact with chiropractors, we either see denial or we hear the argument that such events are but extreme rarities. To the latter, I usually respond that, in the absence of a monitoring system, nobody can tell how often serious adverse events happen. The resply often is this:

You are mistaken because the Royal College of Chiropractors’ UK-based Chiropractic Patient Incident Reporting and Learning System (CPiRLS) monitors such events adequately. 

I have heard this so often that it is time, I feel, to have a look at CPiRLS. Here is what it says on the website:

CPiRLS is a secure website which allows chiropractors to view, submit and comment on patient safety incidents.

Access to CPiRLS

CPiRLS is currently open to all UK-based chiropractors, all ECU members and members of the Chiropractic and Osteopathic College of Australasia. To access the secure area of the CPiRLS website, please click the icon below and insert the relevant CPiRLS username and password when prompted.

In the UK, these can normally be found on your Royal College of Chiropractors’ membership card unless the details are changed mid-year. Alternatively, email from your usual email address and we will forward the details.

Alternatively, in the UK and overseas, secure access details can be obtained from your professional association.

National associations and organisations wishing to use CPiRLS, or obtain trial access to the full site for evaluation purposes, should contact The Royal College of Chiropractors at

Please click the icon below to visit the CPiRLS site.

Yes, you understood correctly. The public cannot access CPiRLS! When I click on the icon, I get this:

Welcome to CPiRLS

CPiRLS, The Chiropractic Patient Incident Reporting and Learning System – is an online reporting and learning forum that enables chiropractors to share and comment on patient safety incidents.

The essential details of submitted reports are published on this website for all chiropractors to view and add comments. A CPiRLS team identifies trends among submitted reports in order to provide feedback for the profession. Sharing information in this way helps to ensure the whole profession learns from the collective experience in the interests of patients.

All chiropractors are encouraged to adopt incident reporting as part of a blame-free culture of safety, and a routine risk management tool.

CPiRLS is secure and anonymous. There is no known way that anyone reporting can be identified, nor do those running the system seek to identify you. For this security to be effective, you require a password to participate.

Please note that reporting to CPiRLS is NOT a substitute for the reporting of patient safety incidents to your professional association and/or indemnity insurers.

So, how useful is CPiRLS?

Can we get any information from CPiRLS about the incidence of adverse effects?


Do we know how many strokes or deaths have been reported?


Can chiropractors get reliable information from CPiRLS about the incidence of adverse effects?

No, because reporting is not mandatory and the number of reports cannot relate to incidence.

Are chiropractors likely to report adverse effects?

No, because they have no incentive and might even feel that it would give their profession a bad name.

Is CPiRLS transparent?


Is CPiRLS akin to postmarketing surveillance as it exists in conventional medicine?


How useful is CPiRLS?

I think I let my readers answer this question.


Earlier this year, I started the ‘WORST PAPER OF 2022 COMPETITION’. As a competition without a prize is no fun, I am offering the winner (that is the lead author of the winning paper) one of my books that best fits his/her subject. I am sure this will overjoy him or her.

And how do we identify the winner? I will continue blogging about nominated papers (I hope to identify about 10 in total), and towards the end of the year, I let my readers decide democratically.

In this spirit of democratic voting, let me suggest to you ENTRY No 8 (it is so impressive that I must show you the unadulterated abstract):


Female sexual dysfunction (FSD) seriously affects the quality of life of women. However, most women do not have access to effective treatment.


This study aimed to determine the feasibility and effectiveness of the use of acupuncture in FSD treatment based on existing clear acupuncture protocol and experience-supported face-to-face therapy.


A retrospective analysis was performed on 24 patients with FSD who received acupuncture from October 2018 to February 2022. The Chinese version of the female sexual function index , subjective sensation, sexual desire, sexual arousal, vaginal lubrication, orgasm, sexual satisfaction, and dyspareunia scores were compared before and after the treatment in all 24 patients.

Main Outcome Measure

A specific female sexual function index questionnaire was used to assess changes in female sexual function before and after the acupuncture treatment.


In this study, the overall treatment improvement rate of FSD was 100%. The Chinese version of the female sexual function index total score, sexual desire score, sexual arousal score, vaginal lubrication score, orgasm score, sexual satisfaction score, and dyspareunia score during intercourse were significantly different before and after the treatment (P < .05). Consequently, participants reported high levels of satisfaction with acupuncture. This study indicates that acupuncture could be a new and effective technique for treating FSD. The main advantages of this study are its design and efficacy in treating FSD. To the best of our knowledge, this is the first study to evaluate the efficacy of acupuncture in the treatment of FSD using the female sexual function index scale from 6 dimensions. The second advantage is that the method used (ie, the nonpharmacological method) is simple, readily available, highly safe with few side effects, and relatively inexpensive with high patient satisfaction. However, limitations include small sample size and lack of further detailed grouping, pre and post control study of patients, blank control group, and pre and post control study of sex hormones.


Acupuncture can effectively treat FSD from all dimensions with high safety, good satisfaction, and definite curative effect, and thus, it is worthy of promotion and application.

My conclusion is very different: acupuncture can effectively kill any ability for critical thinking.

I hardly need to list the flaws of this paper – they are all too obvious, e.g.:

  • there is no control group; the results might therefore be due to a host of factors that are unrelated to acupuncture,
  • the trial was too small to allow far-reaching conclusions,
  • the study does not tell us anything about the safety of acupuncture.

The authors call their investigation a ‘pilot study’. Does that excuse the flimsiness of their effort? No! A pilot study cannot draw conclusions such as the above.

What’s the harm? you might ask; nobody will ever read such rubbish and nobody will have the bizarre idea to use acupuncture for treating FSD. I’m afraid you would be wrong to argue in this way. The paper already got picked up by THE DAILY MAIL in an article entitled “Flailing libido? Acupuncture could help boost sex drive, scientists say” which was as devoid of critical thinking as the original study. Thus we can expect that hundreds of desperate women are already getting needled and ripped off as we speak. And in any case, offensively poor science is always harmful; it undermines public trust in research (and it renders acupuncture research the laughing stock of serious scientists).


England’s record goalscorer Ellen White has revealed she suffered a punctured lung while receiving acupuncture treatment. The injury accelerated her decision to retire. White, 33, said she was still coming to terms with the “traumatic” injury.

Manchester City had sourced a “specialist” – evidently not such an excellent acupuncturist because the complication is avoidable with proper knowledge of anatomy – outside the club to provide her with acupuncture to treat her back problem because of a high number of injuries in the squad at the time. “If you’d said to me two or three years ago that you’re going to retire, I would have said ‘absolutely not’, but I’ve got to a time in my career,” she said. “I had a challenging time last year – coming back from the Olympics, I basically punctured my lung, and it was a lot for me to have to go through and a big reason that accelerated my want to retire.”

The injury happened when she returned to her club with a back spasm last summer. “It punctured my lung which isn’t something that happens normally, obviously,” she said. “It was a really traumatic time for me and something that I’m still figuring out now, still working through. I had to wait for the lung to basically inflate again. I had a needle put into my chest to drag all the air out then hopefully the lung would inflate again – which it has. At the time, I think for me, I just got into a zone of: ‘I need to get back playing. We’ve got these games – I want to be back playing for my club; I want to be back playing for England. I went very tunnel vision,” she said. “It wasn’t until a good two or three months later, it just hit me like a train, what actually happened and how traumatic it was.”

Despite her quick return to goalscoring form, which included becoming the Lionesses record goalscorer in November, the striker says she is still affected by the injury and suffers “phantom pain” where it feels like it is happening again. “It’s important for me now to tell my story, and say it was a big factor in my year and leading up to the decision of wanting to retire. Obviously, there are other factors that come into that as well. I don’t want it to happen to anybody else again is my main thing. I don’t want to walk away from the sport having not told it and not say that I want things in place for it not to happen to anyone else.”


Pneumothorax is by far the most common of all the serious, potentially fatal complications caused by acupuncture. In thin individuals, several acupuncture points over the upper thorax are just a few centimeters away from the lung. Therefore, it is easily possible to puncture a lung by inserting an acupuncture needle. This is from my 2010 review of the subject:

About 90 deaths after acupuncture have been anecdotally documented in the medical literature. Thus, acupuncture has been associated with more deaths than most other ‘alternative’ therapies except herbal medicine … The fatalities are usually due to an acupuncture needle penetrating a vital organ. This, in turn, can cause pneumothorax, cardiac tamponade, or major haemorrhage. Most instances of this nature are reported in the Asian literature which, for most of us, is not easily accessible.

A 2013 review of ours located 1104 cases that had been reported in the Korean literature alone. However, the truth of the matter is that nobody can be sure of the exact incidence figures. Why? Because there is no monitoring system that would reliably record such incidences.

I would argue that every single case of acupuncture-induced pneumothorax tells us that the acupuncturist was not adequately trained. With proper knowledge of anatomy, such complications should not happen. Therefore, such instances are a rude reminder that so-called alternative medicine (SCAM) is far too often in the hands of “specialists” who are a danger to the public.

According to the authors of this study, research is lacking regarding osteopathic approaches in treating polycystic ovary syndrome (PCOS), one of the prevailing endocrine abnormalities in reproductive-aged women. Limited movement of pelvic organs can result in functional and structural deficits, which can be resolved by applying visceral manipulation (VM). Already with these two introductory sentences, I have problems. But for the moment, we can leave this aside and have a look at their trial.

The study was aimed at analyzing the effect of VM on dysmenorrhea, irregular, delayed, and/or absent menses, and premenstrual symptoms in PCOS patients.

Thirty Egyptian women with PCOS, with menstruation-related complaints and free from systematic diseases and/or adrenal gland abnormalities, prospectively participated in a single-blinded, randomized controlled trial. They were recruited from the women’s health outpatient clinic in the faculty of physical therapy at Cairo University, with an age of 20-34 years, and a body mass index (BMI) ≥25, <30 kg/m2. Patients were randomly allocated into two equal groups (15 patients); the control group received a low-calorie diet for 3 months, and the study group received the same hypocaloric diet plus VM to the pelvic organs and their related structures, according to assessment findings, for eight sessions over 3 months. Evaluations for body weight, BMI, and menstrual problems were done by weight-height scale, and menstruation-domain of Polycystic Ovary Syndrome Health-Related Quality of Life Questionnaire (PCOSQ), respectively, at baseline and after 3 months of treatments.

A total of 30 patients were included, with baseline mean age, weight, BMI, and menstruation domain score of 27.5 ± 2.2 years, 77.7 ± 4.3 kg, 28.6 ± 0.7 kg/m2, and 3.4 ± 1.0, respectively, for the control group, and 26.2 ± 4.7 years, 74.6 ± 3.5 kg, 28.2 ± 1.1 kg/m2, and 2.9 ± 1.0, respectively, for the study group. Of the 15 patients in the study group, uterine adhesions were found in 14 patients (93.3%), followed by restricted uterine mobility in 13 patients (86.7%), restricted ovarian/broad ligament mobility (9, 60%), and restricted motility (6, 40%). At baseline, there was no significant difference (p>0.05) in any of the demographics (age, height), or dependent variables (weight, BMI, menstruation domain score) among both groups. Post-study, there was a statistically significant reduction (p=0.000) in weight, and BMI mean values for the diet group (71.2 ± 4.2 kg, and 26.4 ± 0.8 kg/m2, respectively) and the diet + VM group (69.2 ± 3.7 kg; 26.1 ± 0.9 kg/m2, respectively). For the improvement in the menstrual complaints, a significant increase (p<0.05) in the menstruation domain mean score was shown in the diet group (3.9 ± 1.0), and the diet + VM group (4.6 ± 0.5). On comparing both groups post-study, there was a statistically significant improvement (p=0.024) in the severity of menstruation-related problems in favor of the diet + VM group.

The authors concluded that VM yielded greater improvement in menstrual pain, irregularities, and premenstrual symptoms in PCOS patients when added to caloric restriction than utilizing the low-calorie diet alone in treating that condition.

VM involves the manual manipulation by a therapist of internal organs, blood vessels and nerves (the viscera) mostly from outside the body, but sometimes, the therapist also puts his/her fingers into the patient’s vagina. It was developed by the osteopath Jean-Piere Barral. He stated that through his clinical work with thousands of patients, he created this modality based on organ-specific fascial mobilization. And through work in a dissection lab, he was able to experiment with visceral manipulation techniques and see the internal effects of the manipulations. According to its proponents, visceral manipulation is based on the specific placement of soft manual forces looking to encourage the normal mobility, tone, and motion of the viscera and their connective tissues. The idea is that these gentle manipulations may potentially improve the functioning of individual organs, the systems the organs function within, and the structural integrity of the entire body.

I don’t see any reason to believe the concepts of VM are plausible. Thus I find the hypothesis of this trial extremely far-fetched. The results are equally unconvincing. As we have often discussed, the ‘A+B vs B’ design cannot prove a causal relationship between the intervention and the outcome.

The most likely explanation for the findings is that the patients receiving VM experienced or merely reported improvements because the extra attention of mildly invasive treatments produced a powerful placebo effect. To put it bluntly: this is a poor, arguably unethical study where over-enthusiastic researchers reach a conclusion that is not supported by the data.

Despite considerable doubts about its effectiveness, osteopathic manipulative treatment (OMT) continues to be used for a range of pediatric conditions. Here is just one example of many osteopaths advertising their services:

I qualified as an Osteopath in 2009 after 4 years of intensive training from the British College of Osteopathic medicine, where I received a distinction for my efforts. After having two children I decided to do a 2-year Postgraduate training in Pediatric Osteopathy from the Osteopathic Centre for Children in London. Whilst at the centre I was lucky enough to meet a wide variety of children from premature babies in a Neonate Hospital ward to children with developmental issues and disabilities, children on the Autistic spectrum, to kids doing exams or experiencing high levels of stress. We also saw lots of children with normal coughs, colds, lumps and bumps.

And the ‘Institute of Osteopathy states this:

Parents visit osteopaths for a range of reasons to support their child’s health. Children, like adults, can be affected by general joint and muscle issues, which is one of the reasons people visit an osteopath. Parents will also take their children to visit an osteopath for a variety of other health reasons that may benefit from osteopathic care.

As osteopathic care is based on the individual needs of the patient, it will vary depending on your child’s age and the diagnosis. Osteopaths generally use a wide range of gentle hands-on techniques that focus on releasing tension, improving mobility and optimising function. This is often used together with exercise and helpful advice. Some osteopaths have been trained in very gentle techniques which are particularly suitable to assess and treat very young children, including new-borns. You do not need to consult your GP before you visit an osteopath, although you may wish to do so.

So, how good or bad is osteopathy for kids? Our systematic review wanted to find out. Specifically, the aim of this paper is to update our previous systematic review (SR) initially published in 2013 by critically evaluating the evidence for or against this treatment.

Eleven databases were searched (January 2012 to November 2021). Only randomized clinical trials (RCTs) of OMT in pediatric patients compared with any type of controls were considered. The Cochrane risk-of-bias tool was used. In addition, the quality of the evidence was rated using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria, as recommended by the Cochrane Collaboration.

Thirteen trials met the eligibility criteria, of which four could be subjected to a meta-analysis. The findings show that, in preterm infants, OMT has little or no effect on reducing the length of hospital stay (standardized mean difference (SMD) -0.03; 95% confidence interval (CI) -0.44 to 0.39; very low certainty of the evidence) when compared with usual care alone. Only one study (8.3%) was judged to have a low risk of bias and showed no effects of OMT on improving exclusive breastfeeding at one month. The methodological quality of RCTs published since 2013 has improved. However, adverse effects remain poorly reported.

We concluded that the quality of the primary trials of OMT has improved during recent years. However, the quality of the totality of the evidence remains low or very low. Therefore, the effectiveness of OMT for selected pediatric populations remains unproven.

These days, it is not often that I am the co-author of a systematic review. So, allow me to discuss one of my own papers for a change by making a few very brief points:

  • Considering how many osteopaths treat children, the fact that only 13 trials exist is shameful. To me, it suggests that the osteopathic profession has little interest in research.
  • The finding that adverse effects are poorly reported is even more shameful, in my view. It suggests that the few osteopaths who do some research don’t mind violating research ethics.
  • The fact that overall our review fails to yield good evidence that osteopathy is effective for any pediatric condition is the most shameful finding of them all. It means that osteopaths are either not informed about the evidence for their own approach, or that they are informed but don’t give a hoot and treat kids regardless. In both cases, they behave unethically.

Cannabis use is a frequently-discussed subject, not just in the realm of so-called alternative medicine (SCAM). In general, SCAM advocates view it as an herbal medicine and recommend it for all sorts of conditions. They also often downplay the risks associated with cannabis use. Yet, these risks might be substantial.

Cannabis potency, defined as the concentration of Δ9-tetrahydrocannabinol (THC), has increased internationally, which could increase the risk of adverse health outcomes for cannabis users. The first systematic review of the association of cannabis potency with mental health and addiction was recently published in ‘The Lancet Psychiatry’.

The authors searched Embase, PsycINFO, and MEDLINE (from database inception to Jan 14, 2021). Included studies were observational studies of human participants comparing the association of high-potency cannabis (products with a higher concentration of THC) and low-potency cannabis (products with a lower concentration of THC), as defined by the studies included, with depression, anxiety, psychosis, or cannabis use disorder (CUD).

Of 4171 articles screened, 20 met the eligibility criteria:

  • eight studies focused on psychosis,
  • eight on anxiety,
  • seven on depression,
  • and six on CUD.

Overall, higher potency cannabis, relative to lower potency cannabis, was associated with an increased risk of psychosis and CUD. Evidence varied for depression and anxiety. The association of cannabis potency with CUD and psychosis highlights its relevance in healthcare settings, and for public health guidelines and policies on cannabis sales.

The authors concluded that standardisation of exposure measures and longitudinal designs are needed to strengthen the evidence of this association.

The fact that cannabis use increases the risk of psychosis has long been general knowledge. The notion that the risk increases with increased potency of cannabis seems entirely logical and is further supported by this systematic review. Perhaps it is time to educate the public and make cannabis users more aware of these risks, and perhaps it is time that SCAM proponents negate the harm cannabis can do.

Reports of serious complications of chiropractic manipulation keep on coming. Take this one, for instance:

My daughter went for a routine chiropractor appointment. Now she’s paralysed – 1:20 000 chiropractic neck manipulations result in stroke from vertebral artery dissection.

Or take a recent article by US neurosurgeons:

Cranio-cervical artery dissection (CeAD) is a common cause of cerebrovascular events in young subjects with no clear treatment strategy established. This study evaluated the incidence of major adverse cardiovascular events (MACE) in CeAD patients treated with and without stent placement. COMParative effectiveness of treatment options in cervical Artery diSSection (COMPASS) is a single high-volume center observational, retrospective longitudinal registry that enrolled consecutive CeAD patients over a 2-year period. Patients were ≥ 18 years of age with confirmed extra- or intracranial CeAD on imaging. Enrolled participants were followed for 1 year evaluating MACE as the primary endpoint.

One-hundred ten patients were enrolled (age 53 ± 15.9, 56% Caucasian, and 50% male, BMI 28.9 ± 9.2). Grade I, II, III, and IV blunt vascular injury was noted in 16%, 33%, 19%, and 32%, respectively. Predisposing factors were noted in the majority (78%), including

  • sneezing,
  • carrying a heavy load,
  • chiropractic manipulation.

Stent was placed in 10 (10%) subjects (extracranial carotid n = 9; intracranial carotid n = 1; extracranial vertebral n = 1) at the physician’s discretion along with medical management. Reasons for stent placement were early development of high-grade stenosis or expanding pseudoaneurysm. Stented patients experienced no procedural or in-hospital complications and no MACE between discharge and 1 year follow up. CeAD patients treated with medical management only had 14% MACE at 1 year.

The authors concluded that in this single high-volume center cohort of CeAD patients, stenting was found to be beneficial, particularly with development of high-grade stenosis or expanding pseudoaneurysm. These results warrant confirmation by a randomized clinical trial.

Yes, I know: this study was not meant to investigate the link between chiropractic manipulations and CeAD. The finding that chiropractic manipulation is a predisposing factor for CeAD is entirely incidental. But it is an important finding nevertheless.

Chiropractors will laugh about the notion that manipulation is a risk factor akin to sneezing and thus try to trivialize the danger of their treatments. I would then point out that sneezing is unavoidable and fulfills a purpose. Chiropractic manipulations do neither.

Placebo effects are a fascinating subject. In so-called alternative medicine (SCAM), they are particularly important because much of SCAM seems to rely on little more than placebo effects. Therefore, I think this new paper is of some relevance to us.

The aim of this systematic review was to quantify the placebo effect of intraarticular injections for knee osteoarthritis in terms of pain, function, and objective outcomes. Factors influencing placebo effect were investigated.

The authors concluded that the placebo effect of knee injections is significant, with functional improvements lasting even longer than those reported for pain perception. The high, long-lasting, and heterogeneous effects on the scales commonly used in clinical trials further highlight that the impact of placebo should not be overlooked in the research on and management of knee osteoarthritis.

The authors furthermore confirmed that “the main finding of this meta-analysis is that placebo is an important component of the effect of injective treatments for patients with KOA, with saline injections being able to provide relevant and long-lasting results not only in terms of pain relief but also with respect to stiffness resolution and function improvement. These results are both statistically and clinically significant and can be perceived by patients up to 6 months.”

I would dispute that!

To explain why it might help to read our 1995 BMJ paper on the subject:

We often and wrongly equate the response seen in the placebo arm of a clinical trial with the placebo effect. In order to obtain the true placebo effect, other non-specific effects can be identified by including an untreated control group in clinical trials. A review of the literature shows that most authors confuse the perceived placebo effect with the true placebo effect. The true placebo effect is highly variable, depending on several factors that are not fully understood. A distinction between the perceived and the true placebo effects would be helpful in understanding the complex phenomena involved in a placebo response.

In other words, what the authors picked up in their analysis (i.e. the changes that occurred in the placebo groups between the start of a trial and after placebo application) is not just the placebo response; it is, in fact, a combination of a placebo effect, concomitant interventions/care, regression towards the mean, natural history of the condition and possibly other factors.

Does it matter?

Yes, it does!

Placebo effects are not nearly as powerful and long-lasting as the authors conclude. And this means virtually all their implications for clinical practice are incorrect.

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