Long-term changes of body weight in adult obese and non-obese men

In this study the long-term changes of body weight during adulthood in men obese as young adults are compared to those occurring in a random sample from the underlying population. Among 362,200 Danish draftees from 1943 to 1977, 1940 were obese (body mass index greater than or equal to 31 kg/m2). A random sample, comprising 0.5 per cent (1801), was drawn from the remaining population. In 1981-83, 4-40 years later, those living in the same region were invited to a health examination, which was attended by 964 (58 per cent) obese and 1134 (75 per cent) control subjects. In the obese group median change of body weight was 1.3 kg, and in the control group 8.3 kg. Weight change was positively correlated to duration of observation in both groups. Those with lowest body mass index at first examination tended to increase most, and those with highest body mass index tended to lose weight. However, the 5th to 95th percentiles of changes in body weight extended in the obese group from -24 to 29 kg, and in the control group from -2 to 25 kg. The range in weight change increased strikingly with increasing first body mass index exceeding 27 kg/m2. The study indicates that the greater the body mass index among young adult men, the less is the median change in body weight, but the greater is the variation of the body weight changes. These results suggest that the size of the fat mass is subject to intra-individual environmental influences that change over time.