Some information on two important studies on obesity.
Van Dam and his colleagues examined data from 102,400 female nurses in the Nurses’ Health Study II, a prospective study launched in 1989.
At that time, study participants, all aged 24 to 44, reported their current height and weight and their weight at age 18. Researchers calculated body mass index (BMI)--weight in kilograms divided by the square of height in meters.
Participants also answered questions in a number of other areas, including disease history, alcohol consumption, smoking and exercise. Follow-up questionnaires were sent to participants until July 1, 2001, or to the date of death, whichever came first.
The results showed that women with a higher BMI at 18 consumed more alcohol, smoked more and were less likely to engage in vigorous physical activity during adolescence.
During the 12-year follow-up period (1989-2001), in which 710 participants died, the HSPH researchers found that women with a higher BMI at age 18 had a higher risk of dying prematurely.
That was true for even moderately overweight adolescents. Associations between overweight and premature mortality were similar for women who were younger and older than 40 during follow-up. Major causes of death included cancer (258 deaths) and cardiovascular disease (55 deaths); of the deaths due to external causes (144 deaths), suicide was the most common cause (61 deaths).
The researchers also found that women with a low BMI at age 18 did not have an increased risk of mortality
. This finding contrasts with several recent studies, in which both a low and high BMI in middle-aged and older adults was associated with excess mortality. However, at older ages, a low BMI may reflect lifelong smoking habits or weight loss as a result ofdiseases, which may bias associations between BMI and mortality.
Source:
Being Overweight As a Teen Associated With Premature Death in Adulthood, press release of Thursday, October 05, 2006, Harvard School of Public Health
This article below is the biggest study that was ever done.
Study
In 1982, 1,046,154 participants (who had to be at least 30 years old) from the US Cancer Prevention II Study completed questionnaires.
Items included demographic characteristics, personal and family history of disease, height and weight. Out of 457,785 men and 588,369 women, 113,517 men and 88,105 women died during 14 years of follow up (a total of 201,622 deaths).
Body mass index, an index of weight adjusted for height, was calculated (weight [kg] divided by height [m] squared).
The World Health Organisation classifies body mass index as: normal 18.5 to 24.9; grade 1 overweight 25.0 to 29.9; grade 2 overweight 30.0 to 39.9; and grade 3 overweight 40.0 or higher.
The association between body mass index and risk of death from all causes was examined in all participants according to smoking status and history of disease. Healthy non-smokers (84,376 men and 217,857 women) were further examined to see whether this association varied according to age, race or cause of death. (Non-smokers had never smoked).
Full article:
Body Weight and Mortality