Body weight and weight change and their health implications for the elderly

After the age of 60 y, body weight on average tends to decrease. The contri bution of fat mass to this weight loss is relatively small, but fat tends t o be redistributed with advancing age toward more abdominal (particularly v isceral) fat. Anthropometric data are relatively poor indicators of these a ging processes. This may be one of the explanations why the relationship be tween high body mass index and mortality is less pronounced in older than i n younger people. Reduced lipolysis in the visceral fat depot with aging is among potential explanations why increased visceral fat seems to be less h armful in elderly subjects compared to young adults. Even though the relati ve contribution of increased fat mass to mortality may be less pronounced i n elderly people, the impact on disability and functional limitations is fo und to be important from both a clinical and a public health point of view. At the other end of the scale studies have shown that low body mass index and weight loss in the elderly are both strong predictors of subsequent mor tality. This cannot be explained by effects of smoking and early mortality after baseline. There are only few systematic studies comparing the predict ive validity of different anthropometric data for mortality. One recent pro spective study showed that a high waist circumference (in non-smoking men) may be a better predictor of all-cause mortality than high body mass index and waist/hip ratio. Low BMI was a better predictor of mortality than low w aist circumference. In conclusion changes in body composition and fat distr ibution with aging are poorly captured by standard anthropometric data. Low lean body mass is probably better reflected by low BMI, whereas increased (abdominal) fatness is better reflected by increased waist circumference.