Edzard Ernst

MD, PhD, MAE, FMedSci, FRSB, FRCP, FRCPEd.

One of my previous posts was about a press release announcing a ‘WORLDWIDE DECLARATION’, and I promised to comment about the actual declaration. This post firstly reproduces this document and secondly provides a few comments on it. Here is the document:

DEFINITIONS

Traditional, complementary and integrative healthcare (TCIH) refers to the respectful collaboration between various systems of healthcare and their health professionals with the aim of offering a person-centred and holistic approach to health.

ABOUT US

We represent a worldwide community of users and health professionals of TCIH with a large diversity of backgrounds and experiences with a common commitment to the advancement and
promotion of TCIH.

THE HEALTHCARE WE DESIRE

• Focuses on the whole person, including physical, mental, social and spiritual dimensions
• Is patient-centred and supports self-healing and health creation
• Is participative and respects individual choices
• Is evidence-based by integrating clinical experience and patient values with the best available research information
• Respects cultural diversity and regional differences
• Is an integral part of community and planetary health
• Uses natural and sustainable resources that are respectful of the health of our planet
• Integrates traditional, complementary and biomedical practices in a supportive and collaborative manner

We appreciate the benefits of conventional / biomedicine. At the same time we recognize its limitations, including:

• The insufficient therapeutic options that biomedicine provides, especially for chronic / non-communicable diseases (NCDs)
• Frequent side effects of biomedical treatments and rising antimicrobial resistance
• Fragmentation of care from increased specialization and the limits of a disease-based model

We are inspired by countries that are successfully integrating TCIH into their healthcare systems. However, we are concerned about:

• Countries that prevent, limit or undervalue the practice of TCIH
• Uninformed or unbalanced media reporting of TCIH
• Insufficient public funding of TCIH research
• Risk of reduced availability of TCIH and unregulated practices in some countries

OUR CALL TO ACTION

All countries

• Ensure full access to TCIH as part of the right to health for all
• Include TCIH into national health systems
• Provide accreditation of TCIH healthcare professionals in accordance with international training standards to ensure high quality care
• Ensure access and safety of TCIH medicines through specific regulatory pathways
• Fund research on TCIH and disseminate reliable information on TCIH to the public

All healthcare professionals

• Foster respectful collaboration between all healthcare professions towards achieving a person-centred and holistic approach to healthcare

_____________________________

And here are my comments.

  • “TCIH”: in the realm of so-called alternative medicine it seems popular to create a new name for the subject at hand; this one is yet another one in a long line of innovations – sadly, it is as nonsensical as most of the previous ones.
  • Person-centred and holistic approach to health: all good healthcare has these qualities.
  • We represent a worldwide community: really? Who exactly are you then, and what is your ligitimization?
  • Whole person, including physical, mental, social and spiritual dimensions: all good healthcare has these qualities.
  • Patient-centred and supports self-healing and health creation: all good healthcare has these qualities.
  • Respects individual choices: all good healthcare has these qualities.
  • Evidence-based: either they do not know what this term means or they are deliberately misleading the public.
  • Integral part of community and planetary health: all good healthcare has these qualities.
  • Natural and sustainable resources that are respectful of the health of our planet: like Rhino horn and similar ingredients of TCM products?
  • Insufficient therapeutic options that biomedicine provides: yes, conventional medicine is far from perfect, but adding something even less perfect to it cannot improve it.
  • Frequent side effects of biomedical treatments and rising antimicrobial resistance: yes, conventional medicine is far from perfect, but adding something even less perfect to it cannot improve it.
  • Full access to TCIH as part of the right to health for all: the ‘right to health for all’ means the right to the most effective therapies not the right to the most bizarre quackery.
  • Accreditation of TCIH healthcare professionals: giving respectability to every quack would not render healthcare better or safer but worse and more dangerous.
  • Access and safety of TCIH medicines through specific regulatory pathways: regulating access to unproven treatments is nothing less than a recipe for disaster.
  • Research on TCIH: yes in some areas, research might be worthwhile, but it must be rigorously testing TCIH and not promoting it uncritically.
  • Disseminate reliable information on TCIH to the public: thank you! This is my main aim in writing the ~2500 posts on this blog. Yet I do often get the impression that this gets disappointingly little support – and frequently the exact opposite – from enthusiasts of TCIH.

If you go on Twitter you will find that chiropractors are keen like mustard to promote the idea that, after a car accident, you should consult a chiropractor. Here is just one Tweet that might stand for hundreds, perhaps even thousands:

Recovering from a car accident? If you have accident-related injuries such as whiplash, chiropractic care may provide relief. Treatments like spinal manipulation and soft tissue therapy can aid in your recovery.

In case you don’t like Twitter, you could also go on the Internet where you find hundreds of websites that promote the same idea. Here are just two examples:

A frequent injury arising from an automobile accident … is whiplash. After an accident, a chiropractor can help treat resulting issues and pain from the whiplash… Proceeding reduction in swelling and pain, treatment will then focus on manipulation of the spine and other areas.

The primary whiplash treatment for joint dysfunction, spinal manipulation involves the chiropractor gently moving the involved joint into the direction in which it is restricted.

There is no question, chiropractors earn much of their living by treating patients suffering from whiplash (neck injury caused by sudden back and forth movement of the neck often causing neck pain and stiffness, shoulder pain, and headache) after a car accident with spinal manipulation.

Why?

There are two not mutually exclusive possibilities:

  1. They think it is effective.
  2. It brings in good money.

I have no doubt about the latter notion, yet I think we should question the first. Is there really good evidence that chiropractic manipulations are effective for whiplash?

When I was head of the PMR department at the University of Vienna, treating whiplash was my team’s daily bread. At the time, our strategy was to treat each patient according to the whiplash stage and to his/her individual signs and symptoms. Manipulations were generally considered to be contra-indicated. But that was about 30 years ago. Perhaps the evidence has now changed. Perhaps manipulation therapy has been shown to be effective for certain types of whiplash injuries?

To find out, I did a few Medline searches. These did, however, not locate compelling evidence for spinal manipulation as a treatment of any stage of whiplash injuries. Here is an example of the evidence I found:

In 2008, the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders (Neck Pain Task Force) found limited evidence on the effectiveness of manual therapies, passive physical modalities, or acupuncture for the management of whiplash-associated disorders (WAD) or neck pain and associated disorders (NAD). This review aimed to update the findings of the Neck Pain Task Force, which examined the effectiveness of manual therapies, passive physical modalities, and acupuncture for the management of WAD or NAD. Its findings show the following: Evidence from 15 evaluation studies suggests that for recent neck pain and associated disorders grades I-II, cervical and thoracic manipulation provides no additional benefit to high-dose supervised exercises.

But this is most puzzling!

Why do chiropractors promote their manipulations for whiplash, if there is no compelling evidence that it does more good than harm? Again, there are two possibilities:

  1. They erroneously believe it to be effective.
  2. They don’t care but are in it purely for the money.

Whatever it is – and obviously not all chiropractors would have the same reason – I must point out that, in both cases, they behave unethically. Not being informed about the evidence related to the interventions used clearly violates healthcare ethics, and so does financially not informing and exploiting patients.

 

Sixty thousand people are diagnosed with Parkinson’s disease (PD) each year, making it the second most common neurodegenerative disorder. PD results in a variety of gait disturbances, including muscular rigidity and decreased range of motion (ROM), that increase the fall risk of those afflicted. Osteopathic manipulative treatment (OMT) might address the somatic dysfunction associated with neurodegeneration in PD. Moreover, osteopathic cranial manipulative medicine (OCMM) might improve gait performance by improving circulation to the affected nervous tissue. Are these ideas realistic hypotheses or merely wishful thinking?

This study aimed to determine whether a single session of OMT or OMT + OCMM can improve the gait of individuals with PD by addressing joint restrictions in the sagittal plane and by increasing ROM in the lower limb. It was designed as a two-group, randomized controlled trial in which individuals with PD (n=45) and age-matched healthy control participants (n=45) were recruited from the community. PD participants were included if they were otherwise healthy, able to stand and walk independently, had not received OMT or physical therapy (PT) within 30 days of data collection, and had idiopathic PD in Hoehn and Yahr stages 1.0-3.0.

PD participants were randomly assigned to one of three experimental treatment protocols:

  1. a ‘whole-body’ OMT protocol (OMT-WB), which included OMT and OCMM techniques;
  2. a ‘neck-down’ OMT protocol (OMT-ND), including only OMT techniques;
  3. and a sham treatment protocol.

Control participants were age-matched to a PD participant and were provided the same OMT experimental protocol.

An 18-camera motion analysis system was utilized to capture 3-dimensional (3D) position data in a treadmill walking trial before and after the assigned treatment protocol. Pretreatment and posttreatment hip, knee, and ankle ROM were compared with paired t-tests, and joint angle waveforms during the gait cycle were analyzed with statistical parametric mapping (SPM), which is a type of waveform analysis.

Individuals with PD had significantly reduced hip and knee extension in the stance phase compared to controls (32.9-71.2% and 32.4-56.0% of the gait cycle, respectively). Individuals with PD experienced a significant increase in total sagittal hip ROM (p=0.038) following a single session of the standardized OMT-WB treatment protocol. However, waveform analysis found no significant differences in sagittal hip, knee, or ankle angles at individual points of the gait cycle following OMT-WB, OMT-ND, or sham treatment protocols.

The authors concluded that the increase in hip ROM observed following a single session of OMT-WB suggests that OCMM in conjunction with OMT may be useful for improving gait kinematics in individuals with PD. Longitudinal studies over multiple visits are needed to determine the long-term effect of regular OMT and OMT+OCMM treatments on Parkinsonian gait characteristics.

The study has many significant limitations. For instance, the hypotheses tested lack plausibility and the outcome measures are of doubtful validity. Most importantly, the observed effects are only short term and their clinical relevance is highly questionable.

It has been reported that the US Insurer ‘State Farm’ is fighting a fraudulent scheme that has been exploiting New Jersey’s personal injury protection (PIP) benefits law since 2014. The insurer is seeking to recover $2.6 million in what it claims are fraudulent auto injury claims and a declaratory judgment that it need not pay any further claims submitted by the providers involved in the alleged scheme.

State Farm’s suit accuses 12 chiropractic and spine clinics and doctors of fraud, unjust enrichment, and violations of the New Jersey Insurance Fraud Prevention Act. The insurer alleges these providers used a “predetermined protocol” for all patients and a patient referral system for services that were either not performed or were not medically necessary for the individual patients. Instead, the services were carried out to enrich the defendants by exploiting the patients’ eligibility for PIP benefits, according to the complaint.

The suit accuses the providers of failing to legitimately evaluate patients to determine the true nature of their injuries and of reporting the same or similar findings for all patients to justify a predetermined course of treatment that was substantially the same for all patients. Part of the “predetermined protocol” for patients with soft-tissue injuries of the neck and back consisted of

  • hot and cold packs,
  • chiropractic manipulations,
  • massage,
  • mechanical traction,
  • physical medicine and rehabilitation,
  • and manual therapy.

These treatments were administered to almost every patient on almost every visit, regardless of each patient’s unique circumstances and needs, according to the complaint. The chiropractors are also accused of referring patients to diagnostic clinics, some allegedly illegally owned by the chiropractors, for an “unnecessary and predetermined course of pain management and invasive treatments” including injections. State Farm says they would submit false documentation for each case representing that the treatments were legitimately performed and medically necessary.

The 80-page complaint details case after case where the patient’s responses to questions and tests were the same or similar, allegedly serving as a “pretext to justify” the chiropractors’ wide range of treatments. The defendants in the complaint filed in U.S. District Court for New Jersey are:

  • Tri-County Chiropractic and Rehabilitation Center,
  • Robert Matturro, D.C.,
  • Advanced Spine and Pain Management,
  • Varinder Dhillon, M.D.,
  • Nicholas Rosania, D.C.,
  • Bloomfield UAI,
  • Dov Rand, M.D.,
  • Primary Medical Services,
  • Louis J. Citarelli, M.D.,
  • Chiro Health Center P.C.,
  • Marc Matturro, D.C.
  • Marco Tartaglia, M.D.

_____________________________

This story made me wonder: which of the listed treatments

  • hot and cold packs,
  • chiropractic manipulations,
  • massage,
  • mechanical traction,
  • physical medicine and rehabilitation,
  • and manual therapy

would ever be indicated for patients with soft-tissue injuries of the neck and back? Or more specifically, are chiropractic manipulations indicated or contra-indicated for such problems following a car accident? I fail to see any sound evidence that they are effective. If I am correct, should insurance companies not sue all chiropractors who routinely use manipulations for such cases? If the answer is YES, the sum of 2.6 million might need to be increased by several orders of magnitude.

I reported about the activities of Eurocam before (see here) and I was distinctly underwhelmed with this quackery lobby group. Now they have published a press release about a ‘worldwide declaration’ in favor of integrated medicine. Here is my translation of the press release (I will comment on the actual declaration at a later stage):

With a declaration, Eurocam and the European Federation of Homeopathic Patient’s Association, among others, call for an open scientific discourse, more research funds, and more promotion of young researchers in the field of integrative medicine. The declaration is supported by the German Central Association of Homeopathic Physicians and the Homeopathy Research Institute (HRI), among others. Integrative medicine combines conventional and complementary elements in health care for the benefit of patients. The goal is patient-centred and holistic health care. Already 130 organisations have committed themselves to these goals in the medical care of the population in the Declaration.

Integrative medicine integrates complementary and conventional methods

In addition, the Declaration advocates health care that takes the whole person into account in its psychological, mental, social and spiritual dimensions. Integrative medicine in the sense of the Declaration is patient-centred and supports the body’s own regulatory abilities. In addition, it is participatory and respects individual decisions with regard to medical care. It is committed to the evidence of medical procedures, which is based on experience, patient preferences and research findings. It incorporates cultural diversity and regional differences as well as the concepts of community health and planetary health. Integrative medicine uses natural and sustainable resources and integrates complementary and conventional medical procedures.

Integrative medicine: Opportunities especially for chronic diseases and side effects

The supporters of the Declaration see opportunities for integrative medicine above all in chronic and non-communicable diseases, as well as in the frequent side effects of conventional therapies and increasing antibiotic resistance. Conventional medicine is characterised by fragmentation and divisional thinking within medical care, as well as by the increasing specialisation of the health professions. The holistic view of the patient is thus left out. Against this backdrop, the Declaration advocates anchoring integrative medicine as a legal entitlement in health care and integrating it into national health care systems. International training standards should be adapted with integrative medicine in mind, and research projects should be promoted. At the same time, balanced and high-quality patient information is needed.

________________________________

This press release requires a few short comments, in my view:

  • “Integrative medicine combines conventional and complementary elements in health care for the benefit of patients.” Anyone who cares to research for longer than 10 minutes will find that very often the complementary elements are unproven and disproven treatments.
  • “The goal is patient-centred and holistic health care.” By integrating unproven and disproven treatments into routine care, medicine cannot become more patient-centred but must get less effective and more expensive.
  • “The Declaration advocates health care that takes the whole person into account in its psychological, mental, social and spiritual dimensions.” Any good healthcare aims at doing this.
  • “Individual decisions with regard to medical care” are respected in all forms of healthcare.
  • “Side effects of conventional therapies and increasing antibiotic resistance” are regrettable phenomena and much research is going on to minimize them. So-called alternative medicine (SCAM) has not yet been shown to offer a single solution to these problems.
  • “The holistic view of the patient is left out” in conventional medicine. One of the most popular fallacies with SCAM advocates is the strawman fallacy.

I find the text almost comical. It reveals thought processes that lack even the most fundamental rules of logic. One really does get the impression that it had been written by people who are deplorably naive, misinformed, and quite frankly stupid.

 

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.

Lots of people have commented on King Charles’ swollen hands which can be seen in many pictures, not least the one on the cover of my biography of Charles. The king himself repeatedly referred to his ‘sausage fingers’ and has made light of the issue as far back as 1982. When William was born. At that time, he wrote to a friend: “I can’t tell you how excited and proud I am. He really does look surprisingly appetising and has sausage fingers just like mine.”

Now that he is King, we might need to worry; are his ‘sausage fingers’ a sign of a serious underlying disease?

Swollen fingers are normally due to fluid retention which can have many causes, e.g.:

Charles, The Alternative Prince: An Unauthorised Biography

  • allergy,
  • arthritis,
  • bursitis,
  • carpal tunnel syndrome,
  • diabetes,
  • gout,
  • heart failure,
  • injury,
  • infection,
  • kidney failure,
  • lymphoedema,
  • scleroderma,
  • sickle cell disease,
  • syphilis,
  • tendinitis,
  • tuberculosis.

The list is long and it contains some worrying diseases. Luckily, we can exclude many of them simply because Charles has had ‘sausage fingers’ for so many years. Thus, plausible options could be diabetes and scleroderma. The former can probably be excluded mainly because we would have long known about it.

But what about scleroderma?

Scleroderma (or systemic sclerosis, as it is also called) is a serious autoimmune condition that may be localized or generalized. The latter form is more serious. In 2020, it was noted that Charles’s feet also seemed to be swollen. In addition, his face often looks flushed (see also the cover of my book).

I know far too little about Charles’s health to make even a tentative diagnosis. Some features of scleroderma fit quite well, while others do not. In any case, I do hope Charles’s swellings have a more benign explanation. But, if scleroderma is the cause, the question obviously arises: is there a so-called alternative medicine (SCAM) for it?

A recent review stated that some study results have shown that vitamins D and E, probiotics, turmeric, l-arginine, essential fatty acids, broccoli, biofeedback, and acupuncture may be beneficial in systemic sclerosis care. However, large randomized clinical trials have not been conducted. In other words, SCAM has no proven benefit for the condition, and I would not recommend it.

Charles does know that, of course. In the past, he regularly made grand proclamations in favor of SCAM but, as soon as he was really ill, he always employed the best conventional healthcare can offer.

When I first heard about it, I thought it was a hoax – nobody can be that daft, I felt. Then I did a bit of research and found that I had been wrong: some people evidently can be that daft and are trying to promote a new SCAM.

Yes, I am speaking of SPERM SMOOTHIES.

And it’s not even a new thing. One sperm smoothie fan boasted 2 years ago: “My immune system is far stronger than it’s ever been. I no longer catch colds or the flu — even when my children get sick from school! I have such high energy levels, feel positive and enthusiastic and have focus and clarity throughout my day whilst most parents feel tired, crave junk food and struggle with forgetfulness.”

In 2021, THE SUN reported this :

Tracy Kiss, 33, from Buckinghamshire, previously told how she put a spoonful of her best friend’s donated semen into her drink every morning in a bid to boost her immunity.

The personal trainer, who is mum to Millie and Gabrille,  has previously advocated using sperm as a facial ointment.

She spoke as celebrity facialist Chelsee Lewis claimed it actually worked to reduce wrinkles.

On her bizarre beverage concoction, Tracy said: “I’d been feeling run down and had no energy, but now I’m full of beans and my mood has improved.

“It can taste really good – depending on what my friend has been eating. My other mates think I’m strange, but I don’t give a toss.”

Tracy, who is a vegan, roped her single pal into giving her his semen. She previously told how he pops round with a fresh tub three times a week.

“I know he’s healthy, doesn’t smoke, drink or do drugs and I made him have an STI check,” she said.

“When I first approached him, he was concerned I’d use it to impregnate myself.

“But once I’d convinced him it was for my beauty regime he agreed – after all, he has a regular supply at hand!”

Tracy, a qualified nutritional adviser and personal trainer, told how she kept it in her fridge.

She mixes the semen with fruit, seeds, coconut or almond milk – but is also happy to drink it on its own.

“Every batch tastes different, depending on what he’s been eating,” she said.

“If he’s been drinking alcohol or eaten something particularly pungent like asparagus, I ask him to give me a heads up so I know not to drink it neat.

“Things like pineapple and peppermint make it taste better, but I’ll happily take it straight off a spoon usually.”

Tracy has filmed a YouTube video where she talks through her unusual remedy and explains what it tastes like.

“We look at its smoothness and texture, discuss its benefits and then I show people who I use a teaspoon to eat the sperm,” she said.

“Sperm is an awesome product and we should stop being so ridiculous about it – the health benefits have been well researched and more women and men should take advantage of it particularly as its made by our own bodies and doesn’t contain e-numbers and chemicals.”

________________________________

The question I ask myself is this: are sperm smoothies really a new SCAM or are they just a way for some strange people to get their 5 minutes of fame? I sincerely hope it is the latter.

All healthcare professionals have an ethical obligation to be truthful and act in the best interest of the patient by adhering to the best available evidence. Providing false or misleading information to patients or consumers is thus a breach of medical ethics. In Canada, the authorities have started taking action against nurses that violate these ethical principles.

Now it has been reported that a former registered nurse in West Kelowna has been suspended for four weeks after giving a vulnerable client anti-vaccine information and recommending “alternative pseudoscience” treatments.

According to the terms of a consent agreement posted on the B.C. College of Nurses and Midwives site, Carole Garfield was under investigation for actions that happened in September 2021. The college claims that Garfield contacted the client when she was off duty, using her personal mobile phone and email to give information against the COVID-19 vaccine and recommending so-called alternative medicine (SCAM). The exact nature of the “pseudoscience modalities” Garfield recommended to the client was not listed in the college’s notice.

Garfield’s nursing licence was cancelled back in April, according to the college’s registry. It’s unclear how exactly the four-week suspension will be applied. In addition to her month-long suspension and a public reprimand, Garfield is not allowed to be the sole nurse on duty for six months. She will also be given education about ethics, boundaries, and client confidentiality, as well as the province’s professional nursing standards. “The inquiry committee is satisfied that the terms will protect the public,” read a statement from the college.

In my view, it is high time for professional bodies to act against healthcare professionals who issue misleading information to their patients. In the realm of so-called alternative medicine (SCAM), issuing false or misleading information is extremely common and causes untold harm. Such harm would be largely preventable if the professional bodies in charge would start acting responsibly in the best interest of patients. It is high time that they follow the Canadian example!

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.
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