Dr Katherine Flegal and colleagues from Maryland, USA estimated cause-specific excess deaths associated with underweight (A body mass index (BMI) less than 18.5), overweight (BMI 25 to 30 or less), and obesity (BMI 30).
|The Journal of the American Medical Association|
The research team assessed cause-specific relative risks of mortality from the first National Health and Nutrition Examination Survey from 1971 to 1975, and the second from 1976 to 1980.
The third survey was conducted between 1988 and 1994.
Mortality was follow-up through 2000 with 571,042 person-years of follow-up.
The team combined mortality data with data on BMI, and other covariates from National Health and Nutrition Examination Survey between 1999 and 2002.
The researchers evaluated the underlying cause of death information for 2.3 million adults 25 years from 2004 vital statistics data for the United States.
The team evaluated cause-specific excess deaths in 2004 by BMI levels for categories of cardiovascular disease, cancer, and all other causes.
Based on total follow-up, underweight was associated with significantly increased mortality from noncancer, non-cardiovascular disease causes.
However, overweight was not associated with cancer or cardiovascular disease mortality.
The researchers found that overweight was associated with significantly decreased mortality from noncancer, non-cardiovascular disease causes.
However, the team observed that overweight was not associated with cancer or cardiovascular disease mortality.
Obesity was associated with significantly increased cardiovascular disease mortality.
However, obesity was not associated with non-obesity related cancer mortality or with noncancer, and non-cardiovascular disease mortality.
The team found in further analyses, that overweight and obesity combined were associated with increased mortality from diabetes and kidney disease.
Overweight and obesity combined were associated with decreased mortality from other noncancer, non-cardiovascular disease causes.
Obesity was associated with increased mortality from cancers considered obesity-related (including colon cancer), but not associated with mortality from other cancers.
The team found comparisons across surveys suggested a decrease in the association of obesity with cardiovascular disease mortality over time.
Dr Flegal's team concluded, "The BMI-mortality association varies by cause of death."
"These results help to clarify the associations of BMI with all-cause mortality."