l******g
发帖数: 115 | 1 Excess Pounds, but Not Too Many, May Lead to Longer Life
By RONI CARYN RABIN
Published: June 25, 2009
Being overweight won’t kill you — it may even help you live longer. That’
s the latest from a study that analyzed data on 11,326 Canadian adults, ages
25 and older, who were followed over a 12-year period.
The report, published online last week in the journal Obesity, found that
overall, people who were overweight but not obese — defined as a body mass
index of 25 to 29.9 — were actually less likely to die than people of
normal weight, defined as a B.M.I. of 18.5 to 24.9.
By contrast, people who were underweight, with a B.M.I. under 18.5, were
more likely to die than those of average weight. Their risk of dying was 73
percent higher than that of normal weight people, while the risk of dying
for those who were overweight was 17 percent lower than for people of normal
weight.
The finding adds to a simmering scientific controversy over the optimal
weight for adults. In 2007, scientists at the Centers for Disease Control
and Prevention and the National Cancer Institute reported that overweight
adults were less likely than normal weight adults to die from a variety of
diseases, including infections and lung disease.
“Overweight may not be the problem we thought it was,” said Dr. David H.
Feeny, a senior investigator at Kaiser Permanente Center for Health Research
in Portland, Ore., and one of the authors of the study. “Overweight was
protective.”
He said the finding may be due to the fact that a little excess weight is
protective for the elderly, who are at greatest risk for dying, or because
many health conditions associated with being overweight, like high blood
pressure, are being treated with medication.
The study took into account smoking status, physical activity, age, gender
and alcohol consumption. It included a separate analysis excluding those who
died early in the 12-year period, in order to weed out participants who
might have been thin because they were smokers or had an underlying disease,
like cancer. | g*2
发帖数: 658 | 2 good study. i figure one bias is that white population is the only group was
studied. this conclusion may not apply to other ethnic groups, such as
Asian, black, Hispanic.
ages
mass
【在 l******g 的大作中提到】
: Excess Pounds, but Not Too Many, May Lead to Longer Life
: By RONI CARYN RABIN
: Published: June 25, 2009
: Being overweight won’t kill you — it may even help you live longer. That’
: s the latest from a study that analyzed data on 11,326 Canadian adults, ages
: 25 and older, who were followed over a 12-year period.
: The report, published online last week in the journal Obesity, found that
: overall, people who were overweight but not obese — defined as a body mass
: index of 25 to 29.9 — were actually less likely to die than people of
: normal weight, defined as a B.M.I. of 18.5 to 24.9.
| G***a
发帖数: 27294 | 3 有很大的ｃｏｎｆｏｕｎｄ啊！！
37岁超重的白人（２４．５－－２９），很有可能年轻时候ＢＭＩ正常。
那么假设其中有两拨人，一拨人是Ａ，一拨人是Ｂ。假设各有２０个人。
他们年轻时候，都正常ＢＭＩ，假如都活着，中年以后都超重。
假定Ａ组本身就有很大早死的ｒｉｓｋ，比如遗传病，或者爱冒险，吸毒啥的
假定Ｂ组人，早死ｒｉｓｋ低，没遗传病，生活老实健康。这种情况下，
按他们方法，从２５岁ｆｏｌｌｏｗ１２年，Ｂ组人全活下来了。Ａ组死了假设５个人
那么Ｂ组的人的平均体重按这２０个人，３７岁时候体重算
Ａ组呢？15个人按37岁算，剩下的人的体重，肯定算20多岁/30出头死的时候得体重吧
？
那可不就得出来，超重的人活得长嘛！～ （白人２５岁到３７岁，体重增长很快的）
简单的总结，体重和年龄大大correlate, 年龄又和生死大大correlate
如果一个variable，和independent variable和dependent variable都correlate
就是confound ！！！！ ----Statistic 101 ！！！
ages
mass
【在 l******g 的大作中提到】
: Excess Pounds, but Not Too Many, May Lead to Longer Life
: By RONI CARYN RABIN
: Published: June 25, 2009
: Being overweight won’t kill you — it may even help you live longer. That’
: s the latest from a study that analyzed data on 11,326 Canadian adults, ages
: 25 and older, who were followed over a 12-year period.
: The report, published online last week in the journal Obesity, found that
: overall, people who were overweight but not obese — defined as a body mass
: index of 25 to 29.9 — were actually less likely to die than people of
: normal weight, defined as a B.M.I. of 18.5 to 24.9.
| g*2
发帖数: 658 | 4 这是一个挺大的流行病学调查，一定做了on condition的, 如condition regression
model.最后它不是说take into account 一堆variants嘛
【在 G***a 的大作中提到】
: 有很大的ｃｏｎｆｏｕｎｄ啊！！
: 37岁超重的白人（２４．５－－２９），很有可能年轻时候ＢＭＩ正常。
: 那么假设其中有两拨人，一拨人是Ａ，一拨人是Ｂ。假设各有２０个人。
: 他们年轻时候，都正常ＢＭＩ，假如都活着，中年以后都超重。
: 假定Ａ组本身就有很大早死的ｒｉｓｋ，比如遗传病，或者爱冒险，吸毒啥的
: 假定Ｂ组人，早死ｒｉｓｋ低，没遗传病，生活老实健康。这种情况下，
: 按他们方法，从２５岁ｆｏｌｌｏｗ１２年，Ｂ组人全活下来了。Ａ组死了假设５个人
: 那么Ｂ组的人的平均体重按这２０个人，３７岁时候体重算
: Ａ组呢？15个人按37岁算，剩下的人的体重，肯定算20多岁/30出头死的时候得体重吧
: ？
| G***a
发帖数: 27294 | 5 没有paper，凭什么相信它做得是valid的？
consider age，它只能说consider活着的人的age/
有死人的情况，就必须上survival analysis, 不能做regression啊
【在 g*2 的大作中提到】
: 这是一个挺大的流行病学调查，一定做了on condition的, 如condition regression
: model.最后它不是说take into account 一堆variants嘛
| g*2
发帖数: 658 | 6 see "The report, published online last week in the journal Obesity...."
haven't read the entire paper and cannot comment more on it.
i reviewed papers when i was doing research. statics is a must to see and
verify. since it has been published, should be verified.
【在 G***a 的大作中提到】
: 没有paper，凭什么相信它做得是valid的？
: consider age，它只能说consider活着的人的age/
: 有死人的情况，就必须上survival analysis, 不能做regression啊
| P**********w
发帖数: 1175 | 7 By contrast, people who were underweight, with a B.M.I. under 18.5, were
more likely to die than those of average weight. Their risk of dying was 73
percent higher than that of normal weight people, while the risk of dying
for those who were overweight was 17 percent lower than for people of normal
weight.
-- MARK | G***a
发帖数: 27294 | 8 你没看整篇paper, 第一句话就说"good study“ ？ ////
这不能够吧？/// 没见过你这么nice的reviewer~~~
【在 g*2 的大作中提到】
: see "The report, published online last week in the journal Obesity...."
: haven't read the entire paper and cannot comment more on it.
: i reviewed papers when i was doing research. statics is a must to see and
: verify. since it has been published, should be verified.
| G***a
发帖数: 27294 | 9 还真让我找到原文了
http://xa.yimg.com/kq/groups/9196911/56873634/name/oby2009191a.
flaw太多了，看都看不下去了。。
and
【在 g*2 的大作中提到】
: see "The report, published online last week in the journal Obesity...."
: haven't read the entire paper and cannot comment more on it.
: i reviewed papers when i was doing research. statics is a must to see and
: verify. since it has been published, should be verified.
|
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