Posts about medical studies

Exercise Is Really Really Good for You

Nice webcast that reviews the benefits of exercise that are confirmed by medical studies.

Other than [not] smoking there are few modifiable risk factors that seem to have the huge impact on heath activity does…

150 minutes a week of moderate (walking briskly, biking, even mowing the lawn maybe) activity (30 minutes a day 5 days a week) is a decent target for a minimum amount of activity for most people. I have not bought a car since my move (2 months ago) and walk to the grocery store, library, bank, subway, restaurants which is easily 30 minutes and usually more each trip. And for further away places I am biking.

Another option is 25 minutes of vigorous activity 3 times a week and 2 days a week of weight training. Basketball is my favorite form of vigorous activity and sometimes my biking and yard work reach that mark. I like swimming (and I did swim a fair amount when I had a pool at my condo but I don’t swim now as it isn’t right downstairs from my bedroom). I like vigorous activity as I end up feeling refreshed and it serves as a noticeable form of stress release for me.

Related: Better Health Through Exercise, Not Smoking, Low Weight, Healthy Diet and Low Alcohol IntakeExamining the Scientific Basis Around Exercise and Diet ClaimsInactivity Leads to 5.3 Million Early Deaths a Year

Better Health Through: Exercise, Not Smoking, Low Weight, Healthy Diet and Low Alcohol Intake

These 5 activities/state reduce the risk of chronic diseases: regular exercise, not smoking, healthy bodyweight, healthy diet and low alcohol intake. How these were defined

  • not smoking
  • body mass index (BMI): 18 to under 25
  • diet: target was to be 5 portions of fruit and/or vegetables a day, but since almost no one meet that target they reduced the acceptable rate to 3 as accepted as ‘healthy.” Also a diet with less than 30% of calories from fat was required.
  • physical activity: walking two or more miles to work each day, or cycling ten or more miles to work each day, or ‘vigorous’ exercise described as a regular habit
  • alcohol: three or fewer units per day, with abstinence not treated as a healthy behaviour.

Healthy Lifestyles Reduce the Incidence of Chronic Diseases and Dementia: Evidence from the Caerphilly Cohort Study (PLoS open science publication).

The numbers of men judged to be following a healthy lifestyle were as follows: 179 (8%) followed none of the five behaviours, 702 (31%) followed one behaviour, 814 (36%) followed two, 429 (19%) followed three, 111 (5%) followed four or five behaviours and only two (0.1%) followed all five behaviors.

Within a representative sample of middle-aged men, the following of increasing numbers of healthy behaviours was associated with increasing reductions in several important chronic diseases and mortality: an estimated 50% reduction in diabetes, 50% in vascular disease and 60% for all-cause mortality. These results therefore confirm previous studies and provide further data on the association of lifestyle with cognitive impairment and dementia, with a reduction of about 60% in cognitive impairment and about the same in dementia. These reductions, and especially those in cognitive function, are of enormous importance in an ageing population.

Healthy habits reduce dementia risk (Cardiff University press release):

The people who consistently followed four or five of these behaviors exp
experienced a 60 per cent decline in dementia and cognitive decline – with exercise being the strongest mitigating factor – as well as 70 per cent fewer instances of diabetes, heart disease and stroke, compared with people who followed none.

Principle Investigator Professor Peter Elwood from Cardiff University’s School of Medicine. “What the research shows is that following a healthy lifestyle confers surprisingly large benefits to health – healthy behaviours have a far more beneficial effect than any medical treatment or preventative procedure.

Christopher Allen, Senior Cardiac Nurse at the British Heart Foundation, which part-funded the study, said:

“The results of this study overwhelmingly support the notion that adopting a healthy lifestyle reduces your risk of cardiovascular disease and dementia.

Related: Examining the Scientific Basis Around Exercise and Diet ClaimsHealthy Diet, Healthy Living, Healthy WeightStudy Finds Obesity as Teen as Deadly as SmokingPhysical Activity for Adults: Inactivity Leads to 5.3 Million Early Deaths a YearToday, Most Deaths Caused by Lifetime of Action or Inaction

Outdoor Air Pollution Resulted in 223,000 Cancer Deaths in 2010

The specialized cancer agency of the World Health Organization, the International Agency for Research on Cancer (IARC), announced today that it has classified outdoor air pollution as carcinogenic to humans.

After thoroughly reviewing the latest available scientific literature, the world’s leading experts convened by the IARC Monographs Programme concluded that there is sufficient evidence that exposure to outdoor air pollution causes lung cancer. They also noted a positive association with an increased risk of bladder cancer.

Particulate matter, a major component of outdoor air pollution, was evaluated separately and was also classified as carcinogenic to humans.

The IARC evaluation showed an increasing risk of lung cancer with increasing levels of exposure to particulate matter and air pollution. Although the composition of air pollution and levels of exposure can vary dramatically between locations, the conclusions of the Working Group apply to all regions of the world.

Air pollution is already known to increase risks for a wide range of diseases, such as respiratory and heart diseases. Studies indicate that in recent years exposure levels have increased significantly in some parts of the world, particularly in rapidly industrializing countries with large populations. The most recent data indicate that in 2010, 223,000 deaths from lung cancer worldwide resulted from air pollution.

“The air we breathe has become polluted with a mixture of cancer-causing substances,” says Dr Kurt Straif.

The stories of amazingly high (and persistent) air pollution levels in China have been continuing for years. But, while China, likely represents several of the worst existing air pollution conditions hundreds of thousands have died outside China due to air pollution just in the last 5 years.

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Drugmakers Are Desperate to Know Why Placebos Are Getting More Effective

Fascinating article from Wired: Placebos Are Getting More Effective. Drugmakers Are Desperate to Know Why.

The fact that an increasing number of medications are unable to beat sugar pills has thrown the industry into crisis. The stakes could hardly be higher. In today’s economy, the fate of a long-established company can hang on the outcome of a handful of tests.

Potter discovered, however, that geographic location alone could determine whether a drug bested placebo or crossed the futility boundary. By the late ’90s, for example, the classic antianxiety drug diazepam (also known as Valium) was still beating placebo in France and Belgium. But when the drug was tested in the US, it was likely to fail. Conversely, Prozac performed better in America than it did in western Europe and South Africa. It was an unsettling prospect: FDA approval could hinge on where the company chose to conduct a trial.

In one study, Benedetti found that Alzheimer’s patients with impaired cognitive function get less pain relief from analgesic drugs than normal volunteers do. Using advanced methods of EEG analysis, he discovered that the connections between the patients’ prefrontal lobes and their opioid systems had been damaged. Healthy volunteers feel the benefit of medication plus a placebo boost. Patients who are unable to formulate ideas about the future because of cortical deficits, however, feel only the effect of the drug itself. The experiment suggests that because Alzheimer’s patients don’t get the benefits of anticipating the treatment, they require higher doses of painkillers to experience normal levels of relief.

Benedetti often uses the phrase “placebo response” instead of placebo effect. By definition, inert pills have no effect, but under the right conditions they can act as a catalyst for what he calls the body’s “endogenous health care system.” Like any other internal network, the placebo response has limits. It can ease the discomfort of chemotherapy, but it won’t stop the growth of tumors. It also works in reverse to produce the placebo’s evil twin, the nocebo effect. For example, men taking a commonly prescribed prostate drug who were informed that the medication may cause sexual dysfunction were twice as likely to become impotent.

Moreover, a pill’s shape, size, branding, and price all influence its effects on the body. Soothing blue capsules make more effective tranquilizers than angry red ones, except among Italian men, for whom the color blue is associated with their national soccer team—Forza Azzurri!

Medical research presents significant difficulties. The funding of the health care system also distorts behavior and pushes companies to focus on being able to justify selling drugs instead of focusing on finding effective solutions. Even without incentives distorting behavior, the challenges are difficult enough. Adding the distortions just makes it worse.

It is wonderful we have so many scientists accepting these challenges and spending their careers fighting the odds to help find us wonderful health breakthroughs.

Related: The Majority of Clinical Trials Don’t Provide Meaningful EvidenceSystem for Approving New Medical Options Needs ImprovementMedical Study Integrity (or Lack Thereof)Discussing Medical Study Results

System for Approving New Medical Options Needs Improvement

Something Doesn’t Add Up

Not only did the team find that evidence for Infuse’s benefits over existing alternatives for most patients was questionable; they also discovered in a broad array of published research that risks of complications (including cancer, male sterility and other serious side effects) appeared to be 10 to 50 times higher than 13 industry-sponsored studies had shown. And they learned that authors of the early studies that found no complications had been paid between $1 million and $23 million annually by the company for consulting, royalties and other compensation. Carragee, MD ’82, estimates Medtronic has sold several billion dollars’ worth of Infuse for uses both approved and “off label.”

Without a rigorous, data-driven context, medicine’s expensive traditions and hunch-based treatments threaten to bankrupt us. “People say that we shouldn’t delay science; people are dying; we should get new treatments out there. I do not feel the pressure to do that until we have solid evidence,” Ioannidis asserts. “The resources many procedures draw are enormous.” And that leaves insufficient funds for the prevention plans and treatments we know actually work.

I have written about the problems with our health care research system several times. The existing system is in need of improvement and is made much worse by the general state of the broken health care system in the USA. Dr. John P.A. Ioannidis, the focus of the article, is doing fantastic work in this area.

Related: Majority of Clinical Trials Don’t Provide Meaningful EvidenceStatistical Errors in Medical StudiesUSA Spends $7,960 Compared to Around $3,800 for Other Rich Countries on Health Care with No Better Health ResultsDrug Company Funding Taints Published Medical ResearchMistakes in Experimental Design and InterpretationUnderstanding Data

Does Diet Soda Result in Weight Gain?

Most of us want medical studies to provide clearer (more certain, more specific, more universal) indications than they actually provide. The conclusion of medical studies are often very clouded. Each person has a myriad of complex factors effecting how nutrition, activity and medication will affect us. Certain general conclusion can be drawn but it is very complex and difficult to universally state without various equivocations.

Advice For Diet Soda Lovers: Skip The Chips

Researchers at the University of North Carolina-Chapel Hill found that diet soda drinkers who ate a so-called “prudent” diet, rich in fruit, fish, vegetables, whole grains, nuts and milk, were significantly less likely to develop metabolic syndrome over 20 years than those who ate a “Western diet” heavy in fried foods, meats and sugars.

Metabolic syndrome is a condition characterized by excess abdominal fat, elevated blood sugar, high blood pressure, elevated triglycerides and low HDL cholesterol. About 32 percent of the participants in the “Western diet” cluster developed the condition.

The question of whether diet soda truly helps people manage their weight turns out to be a very tough one to answer.

Conflicting findings abound. A large study published in the New England Journal of Medcine last year found that diet soda had no effect on weight. But another one, published in 2008, found that drinking more than three diet drinks a day led to weight gain.

I would like to know, with much greater certainty what nutritional and food related advice I need to consider when making my choices. To a significant degree I think there is going to be quite a bit of uncertainty (much more than we want) for at least the next 30 years (projecting far out into the future with any accuracy seems very difficult to me.

I am skeptical of purely correlational results. You can try to have similar subsets of people but that is actually hard and if you allow for similar groups and then let the choose something (like diet sodas or not) the chance of that actually being a significant choice that results in many other decisions being different between the subgroups seems a big risk (that makes accepting the correlation as evidence as risky). When you have a scientific explanation it makes the evidence much more compelling, but it is also easy to be taken in by explanations meant to fit the results of a study.

I can believe diet soda can do some bad things to your health. I believe if you are trying to reduce your weight by reducing calories drinking diet soda in place of sugary soda is a big help. I can believe drinking water instead of diet soda would be even better. I want caffeine and don’t like coffee. I have cut down drinking Mountain Dew to less than 2 a week. I have substituted diet soda over the last year. I am not sure that is the right choice, but it is the one I have made so far.

Related: Science Continues to Explore Causes of Weight GainStudy Shows Weight Loss From Calorie Reduction Not Low Fat or Low CarbAnother Paper Questions Scientific Paper AccuracyContradictory Medical Studies

Medical Studies Showing Largest Benefits Often Prove to be False

There is another study showing the results of health studies often are proven false. Medical studies with striking results often prove false

If a medical study seems too good to be true, it probably is, according to a new analysis.

In a statistical analysis of nearly 230,000 trials compiled from a variety of disciplines, study results that claimed a “very large effect” rarely held up when other research teams tried to replicate them.

The report should remind patients, physicians and policymakers not to give too much credence to small, early studies that show huge treatment effects, Ioannidis said.

The Stanford professor chose to publish this paper in a closed science publication. But previously he published openly on: Why Most Published Research Findings Are False.

Related: Majority of Clinical Trials Don’t Provide Meaningful EvidenceStatistical Errors in Medical StudiesMistakes in Experimental Design and InterpretationHow to Deal with False Research Findings

Today, Most Deaths Caused by Lifetime of Action or Inaction

Chart of the Leading Causes of Death in 1900 and 2010

Our instincts lead us to fear the unknown and immediate threats (probably so we can be ready to run – or maybe fight). But today the biggest risks to an untimely dealt are not lions, other people out to get us, or even just random infection. We have to adapt to the new risks by taking action to eat healthfully and exercise, in the same way we we have evolved to avoid becoming a meal for a hungry beast.

Today the largest causes of death are heart disease and cancer (which account for more than 60% of the deaths causes by the top 10 leading causes of death). The next leading causes are non-infectious airways diseases, cerebrovascular diseases and accidents. Alzheimer’s, diabetes, nephropathies, pneumonia or influenza and suicide make of the rest of the top 10 leading causes.

In 1900 Pneumonia or influenza and tuberculosis took as many lives (per 100,000 people) and cancer and heart disease take today. We have done well decreasing the incidents of death (fewer deaths per 100,000) by greatly reducing and nearly eliminating some causes of death (the 2 leading causes from 1900 are good examples).

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Majority of Clinical Trials Don’t Provide Meaningful Evidence

The largest comprehensive analysis of ClinicalTrials.gov finds that clinical trials are falling short of producing high-quality evidence needed to guide medical decision-making.

The analysis, published today in the Journal of the American Medical Association, found the majority of clinical trials is small, and there are significant differences among methodical approaches, including randomizing, blinding and the use of data monitoring committees.

This is a critical issue as medical studies continue to leave quite a bit to be desired. Even more importantly the failure to systemically study and share evidence of effectiveness once treatments are authorized leaves a great deal to be desired. On top of leaving quite a bit to be desired, the consequences are serious. If we make mistakes for example in how we date fossils it matters but it is unlikely to cause people their lives or health. Failure to adequately manage and analyze health care experiments may very well cost people their health or lives.

“Our analysis raises questions about the best methods for generating evidence, as well as the capacity of the clinical trials enterprise to supply sufficient amounts of high quality evidence to ensure confidence in guideline recommendations,” said Robert Califf, MD, first author of the paper, vice chancellor for clinical research at Duke University Medical Center, and director of the Duke Translational Medicine Institute.

The analysis was conducted by the Clinical Trials Transformation Initiative (CTTI), a public-private partnership founded by the Food and Drug Administration (FDA) and Duke. It extends the usability of the data in ClinicalTrials.gov for research by placing the data through September 27, 2010 into a database structured to facilitate aggregate analysis.

Related: Statistical Errors in Medical StudiesHow to Deal with False Research FindingsMedical Study Integrity (or Lack Thereof)

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Ritalin Doesn’t Show Long Term Effectiveness for ADHD

From the New York Times opinion piece, Ritalin Gone Wrong, by L. Alan Sroufe is a professor emeritus of psychology at the University of Minnesota’s Institute of Child Development:

Attention-deficit drugs increase concentration in the short term, which is why they work so well for college students cramming for exams. But when given to children over long periods of time, they neither improve school achievement nor reduce behavior problems. The drugs can also have serious side effects, including stunting growth.

To date, no study has found any long-term benefit of attention-deficit medication on academic performance, peer relationships or behavior problems, the very things we would most want to improve. Until recently, most studies of these drugs had not been properly randomized, and some of them had other methodological flaws.

But in 2009, findings were published from a well-controlled study that had been going on for more than a decade, and the results were very clear… At first this study suggested that medication, or medication plus therapy, produced the best results. However, after three years, these effects had faded, and by eight years there was no evidence that medication produced any academic or behavioral benefits.

As I have written before I am skeptical of the amount of drug use our health care system encourages: Lifestyle Drugs and Risk.

Related: Long Term ADHD Drug Benefits Questioned (2009)Nearly 1 million Children Potentially Misdiagnosed with ADHD in the USADiet May Help ADHD Kids More Than DrugsOver-reliance on Prescription Drugs to Aid Children’s Sleep?Epidemic of Diagnoses

Nearly 1 million Children Potentially Misdiagnosed with ADHD in the USA

Nearly 1 million children in the United States are potentially misdiagnosed with attention deficit hyperactivity disorder simply because they are the youngest – and most immature – in their kindergarten class, according to new research by , Todd Elder, a Michigan State University economist.

These children are significantly more likely than their older classmates to be prescribed behavior-modifying stimulants such as Ritalin, said Todd Elder, whose study will appear in a forthcoming issue of the Journal of Health Economics (closed science, unfortunately). Michigan State should stop funding closed journals with free content – other schools have decided to put science first, before supporting a few outdated business models of select journals.

Such inappropriate treatment is particularly worrisome because of the unknown impacts of long-term stimulant use on children’s health, Elder said. It also wastes an estimated $320 million-$500 million a year on unnecessary medication – some $80 million-$90 million of it paid by Medicaid, he said.

ADHD is the most commonly diagnosed behavioral disorder for kids in the United States, with at least 4.5 million diagnoses among children under age 18, according to the Centers for Disease Control and Prevention.

The youngest kindergartners were 60 percent more likely to be diagnosed with ADHD than the oldest children in the same grade. Similarly, when that group of classmates reached the fifth and eighth grades, the youngest were more than twice as likely to be prescribed stimulants.

Overall, the study found that about 20 percent – or 900,000 – of the 4.5 million children currently identified as having ADHD likely have been misdiagnosed.

Related: Lifestyle Drugs and RiskLong Term ADHD Drug Benefits QuestionedMerck and Elsevier Publish Phony Peer-Review Journal

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