Sunday, December 20, 2009

A sly bit of propaganda

A cancer research organization says below that it is a myth that people of middling weight are healthier and claims instead that "Extra weight means extra risk for chronic diseases like cancer". That may be true but it is OVERALL mortality that matters. Extra weight may increase some risks but it decreases others -- e.g. fat women get less breast cancer. It is of course true that BMI can be misleading but it is BMI that most of the alarmist "findings" are based on so they are trying to have their cake and eat it too. I also note that they are willing to control for smoking history but not for social class. They are in other words ready to admit the influence of third factors when it helps their case but other factors are ignored

Last year, a study in the Journal of the American Medical Association concluded that being moderately overweight was not associated with the increase in death rates that was observed among the obese. In fact, that study found that the moderately overweight even had a lower death rate than individuals at normal weight.

This surprising finding bolstered a belief that being 10 or 15 pounds overweight was healthy. One sociology professor interviewed about the study in the New York Times went to so far as to assert that the study proved that what most people consider overweight is actually “the optimal weight.”

Another study appeared late this summer in the British medical journal The Lancet. This study was a review of previous studies on obesity and cardiovascular health among patients with coronary artery disease (CAD). Once again, the conclusion was surprising: as of four years (on average) after being diagnosed with CAD, subjects who fell into the overweight or mildly obese categories had the lowest risk for dying. The authors of the study did not conclude, however, that being overweight is “healthy.”

Instead, they strongly suggested that the most widely-used method to classify overweight and obesity (the body-mass index (BMI), which expresses weight in proportion to height) is simply an imperfect tool. They noted that “these findings could be explained by the lack of discriminatory power of BMI to differentiate between body fat and lean mass.” An accompanying Lancet editorial went further, saying flatly that BMI should be “left aside” as a clinical tool.

Only one week later, in the August 24 issue of the New England Journal of Medicine, a major study appeared that shed new light on those much buzzed-about studies. In the new study, 527,265 men and women who were between 50 and 71 years old at the start of the study had their diets, medical histories and other factors tracked by researchers. After 10 years, 61,317 participants had died. When researchers analyzed the data, they looked at death rates among healthy people who had never smoked. (It was important to eliminate the effect of smoking on weight, because smokers are a paradox: they have higher death rates, but tend not to be overweight or obese.)

When the researchers did this, the effect of overweight and obesity at midlife (age 50) became much easier to measure: overweight people had a 20 to 40 percent higher death rate. (The death rates among obese individuals, depending on their degree of obesity, were double or triple the rate of healthy participants.)

Even so, Collins points out that studies that examine death rates alone are missing something. “Advances in medical care are lessening some of the impact that moderate obesity plays on death rates, but moderately obese individuals are more likely to develop other conditions that lessen quality of life and require multiple medications that come with their own side effects. “Studies link even moderate amounts of excess weight to increased risk for heart disease, high blood pressure, diabetes, and the demand for long-term medications.”

A 2005 study in the Journal of Epidemiology and Community Health followed 6798 middle-aged British men and showed that, after 20 years, subjects who became moderately overweight had a 24% higher risk of cardiovascular disease, and twice the risk of diabetes, than subjects at normal weight. Men who became considerably overweight had 41 percent higher risk of cardiovascular disease and 4 times the risk of diabetes than normal-weight subjects. And those men who became obese over the course of the study increased their risk of cardiovascular disease by 78 percent, and were nearly 8 times as likely to develop diabetes.

The evidence that overweight and obesity increase risk for certain cancers (especially post-menopausal breast cancer) is growing. Carrying extra weight also increases the odds for arthritis, gallstones, gout, sleep apnea and similar conditions caused, directly or indirectly, by the stress of extra weight on the body.


Natural swine flu defence found

Sounds interesting

A previously unknown natural defence against swine flu and other viruses has been discovered which could lead to new treatments. Scientists found that the virus-fighting proteins protected against swine flu when levels were increased. When the proteins were removed the swine flu virus was able to multiply in the body unchecked. The accidental discovery may help to explain why some people develop serious symptoms when they contract flu and others do not.

The protein, IFITM3, and although it appeared to be connected to the functioning of the immune system, how it worked and what it did had never been understood. Professor Stephen Elledge, from Harvard Medical School in Boston, US, who led the research, said: "We've uncovered the first-line defence in how our bodies fight the flu virus. "The protein is there to stop the flu. Every cell has a constitutive immune response that is ready for the virus. If we get rid of that, the virus has a heyday."

The findings, reported in the journal Cell, could pave the way to new kinds of antiviral treatment, say the scientists. However, it remains to be seen what the long-term side effects of boosting levels of the proteins might be.

The news comes as Sir Liam Donaldson, Chief Medical Officer, announced the latest swine flu figures showing a further drop in cases with an estimated 9,000 new diagnoses last week. It is thought over 800,000 people have suffered symptoms of swine flu since it first emerged in England in April. It appears that the second wave of the disease is coming to an end but he warned that it is not know what will happen in the New Year. Sir Liam said the NHS had coped 'brilliantly' with swine flu this year.

The vaccination programme is also progressing with three million people out of the nine million in the first priority groups already immunised. More than 100,000 pregnant women have so far been vaccinated, Prof David Salisbury, head of immunisation said, out of around 550,000 women who are pregnant at any one time in England. Two thirds of local NHS organisations have now reached agreements with GPs to start vaccinating children aged between six months and five years.


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