jenk

DeVita and Timor Hortobágyi found that a person who weighs twice as much as another experiences no greater torque in the knees when both walk at the same, reasonable speed. When the obese volunteers were allowed to walk at a slower speed, which they found more comfortable, they exerted even less force on their knees than people in the other group did at the faster pace. Greater force on the knee had previously been presumed to explain why obese people are susceptible to osteoarthritis in that joint.

Furthermore, DeVita and Hortobágyi reported in 2003, obese volunteers walked with shorter strides and straighter knees than did other people. Those behaviors reduce certain stresses on the joint, DeVita says. - Science News

• During the study, participants were asked to name a "close friend" who would have their address should the researchers have trouble contacting them. This was the basis for the "close friends" connections in the computer model.
  
  
• The increased correlation of obesity between friends? Is actually between men friends. The paper states that the correlations between female-female and mixed-sex friends were "not significant".
  
  
• According to the NY Times, researchers stated that their calculations showed that on average, "a person who became obese gained 17 pounds and the newly obese person’s friend gained five". When you think "became obese", do you think, "gained 17 pounds"? Or do you think, "gained 70 pounds"? (I'm sure some did gain significantly, at the outside of the bell curve, but it's not the average.)
  
  
• A few years ago obesity researcher Jeffrey M. Friedman reminded us weight is even more hereditary than height. One would expect that siblings would have higher correlations than non-siblings (and identical twins higher than non-twins (study)), which makes all the "friends matter more than siblings" in the media look laughable.
  
  
• On the other hand, in the same article, Friedman says that “people can exert a level of control over their weight within a 10-, perhaps a 15-pound range". Five and 17 pounds is pretty close to that 10 to 15 lb range. Which is interesting.

Why do studies continue to find that health risk factors don’t actually predict who will succumb to disease or die early? Why do people with a wide range of numbers (body mass index, blood lipids, blood sugars, blood pressures), diets and lifestyles end up dying around the same time and of the same things? Why don’t risk factors make a bigger, sure-fire difference?

Correlations are not causation. Correlations often contradict each other, and make for downright silly conclusions or advice. Remember this one? — “Women, rack up those frequent flyer miles to lower your risk for miscarriage!”

Being Black is a risk factor for sickle cell anemia but skin whitening won’t do a thing to prevent or cure sickle cell anemia. And “being male is now the single largest demographic risk factor for early mortality in developed countries,” according to Daniel Kruger, a social psychologist at the University of Michigan Institute for Social Research.
[...]
Even the term “disease” increasingly doesn’t refer to actual clinical illness or disability anymore. Some want us to believe that certain risk factors themselves are diseases, too. [Although this is inconsistently applied, depending on whatever is popular to believe or is being sold. While, for instance, the most “morbidly obese” women (the upper 0.2% of the population, even) live longer than normal weight men, obesity is declared a disease, but maleness isn’t!]

Remember whenever you hear the term, risk factor, that it is just a correlation, not a disease, a measure of actual risk, or cause of death.

The biggest risk factor for the diseases that eventually kill all of us is aging. And there’s not much we can do about that one, no matter how much some may want us to believe otherwise. Everything else pales by comparison. In the meantime, less panic and fear, and a lot more balance and common sense, can help all of us get the most out of the lives we have.

( ... )

The average American man is 3 inches taller and 50 pounds heavier than he was at the time of the Civil War ( ... )

the typical Civil War veteran had a body mass index of 23, which put him in the middle of what our public health officials incorrectly label the "normal" range of weight (it was normal to be thin in the 19th century, mainly because so many people were malnourished).

Meanwhile, today's average middle-age male has a BMI of 28, putting him toward the high end of the government's "overweight" category.

Yet middle-age people today are far healthier than their parents were at the same age, who in turn were much healthier than their parents. Rates of most major illnesses, including heart disease, stroke, respiratory diseases and many cancers, have plummeted over the course of the past few generations, and continue to fall.

All this flies in the face of endless waves of hysteria about how the average American's weight imperils his or her health. Indeed, the most recent comprehensive study of the issue found "overweight" people had lower death rates than "normal weight" people, and "obesity" did not even begin to correlate with any increased mortality risk until one reached the fattest 6 percent of the population. ( ... )

( .... )

The difference does not involve changes in genes, as far as is known, but changes in the human form. It shows up in several ways, from those that are well known and almost taken for granted, like greater heights and longer lives, to ones that are emerging only from comparisons of health records.

The biggest surprise emerging from the new studies is that many chronic ailments like heart disease, lung disease and arthritis are occurring an average of 10 to 25 years later than they used to. There is also less disability among older people today, according to a federal study that directly measures it. And that is not just because medical treatments like cataract surgery keep people functioning. Human bodies are simply not breaking down the way they did before.

Even the human mind seems improved. The average I.Q. has been increasing for decades, and at least one study found that a person’s chances of having dementia in old age appeared to have fallen in recent years.

The proposed reasons are as unexpected as the changes themselves. Improved medical care is only part of the explanation; studies suggest that the effects seem to have been set in motion by events early in life, even in the womb, that show up in middle and old age. ( .... )

Scientists used to say that the reason people are living so long these days is that medicine is keeping them alive, though debilitated. But studies like one Dr. Fogel directs, of Union Army veterans, have led many to rethink that notion.

The study involves a random sample of about 50,000 Union Army veterans. Dr. Fogel compared those men, the first generation to reach age 65 in the 20th century, with people born more recently.

The researchers focused on common diseases that are diagnosed in pretty much the same way now as they were in the last century. So they looked at ailments like arthritis, back pain and various kinds of heart disease that can be detected by listening to the heart.

The first surprise was just how sick people were, and for how long. ( .... )

[O]ne group of C.D.C. researchers put it, “Evidence that weight loss improves survival is limited.” We are getting fat, but, Oliver says, we’re not getting sick because of it. ( He argues that researchers are )

too quick to ascribe to weight loss what might be better attributed to the life-style changes that produce weight loss. This, Oliver claims, “is like saying ‘whiter teeth produced by the elimination of smoking reduces the incidence of lung cancer.’ ”

Fat was once considered a sign of substance and now it isn’t. It was once thought sexy and now it’s the opposite. [...] It’s hard to avoid the conclusion that fat became ugly when the poor became fat.

On the Scales: Non-Dieters Weigh the Same, but They're Happier
June 14, 2005 By NICHOLAS BAKALAR
Dieting is not necessarily the royal road to good health.

In a paper published this month in The Journal of the American Dietetic Association, researchers found that obese women who used a nutrition and behavior approach that ignored weight and body mass index, or B.M.I., a common measure of weight in relation to body size, were psychologically healthier at the end of a two-year trial period than those on conventional weight-loss diets.

( Nondieters lost no weight during the trial. Dieters initially lost weight, and then gained it back, showing no weight loss after two years. )

Differences between dieters and nondieters in total cholesterol, H.D.L. cholesterol, L.D.L. cholesterol and blood pressure were insignificant at the end of the study. But nondieters felt significantly better about their bodies and showed highly significant decreases in depression, as measured by a widely used test.

"There is an extraordinary amount of scientific research that documents that dieting is not an effective health or weight-loss strategy," said Dr. Linda Bacon, the lead author. But, she said, "there is abundant research to show that when people make lifestyle changes, they improve health."

People who are overweight but not obese have a lower risk of death than those of normal [or under normal] weight, federal researchers are reporting today. [...] The new study, considered by many independent scientists to be the most rigorous yet on the effects of weight, controlled for factors like smoking, age, race and alcohol consumption in a sophisticated analysis derived from a well-known method that has been used to predict cancer risk. [...T]he new study addressed the risk only of death and not of disability or disease. [...]

The study did not explain why overweight appeared best as far as mortality was concerned. But Dr. Williamson said the reason might be that most people die when they are over 70. Having a bit of extra fat in old age appears to be protective, he said, giving rise to more muscle and more bone. "It's called the obesity paradox," Dr. Williamson said. But, he said, while the paradox is real, the reasons are speculative. "It's raw conjecture," he said.

The new study comes just 13 months after different researchers from the disease control centers published a paper warning that obesity and overweight were causing an extra 400,000 deaths a year and were poised to overtake smoking as the nation's leading preventable cause of premature death. ( ... )

Now the new study says that obesity and extreme obesity are causing about 112,000 extra deaths but that overweight is preventing about 86,000, leaving a net toll of some 26,000 deaths in all three categories combined, compared with the 34.000 extra deaths found in those who are underweight. - From The New York Times

Based on the new calculation, excess weight would drop from the second leading cause of preventable death, after smoking, to seventh. It would fall behind car crashes and guns on the list of killers. - Associated Press