Elderly becoming fatter, less lean

NEW YORK (Reuters Health) - The increasing prevalence of obesity combined with age-related body changes is producing an elderly population that is carrying ever more fat and less lean muscle mass, which may lead to disability and other illnesses like type 2 diabetes and heart disease, doctors warn in a new report.

The obesity epidemic and the aging of the population "could have a dramatic public health impact in the coming years if we do not develop appropriate interventions that target fat loss while preserving skeletal muscle among older adults," Dr. Jingzhong Ding told Reuters Health.

Ding, from Wake Forest University Baptist Medical Center, Winston-Salem, North Carolina, and colleagues looked at the effects of year of birth and age on body composition in 1,786 healthy adults from 1997 to 2003 as part of the Health, Aging and Body Composition Study. The Health ABC Study is investigating the impact of body composition on illness, disability and death in the elderly.

The subjects were in their 70s when they entered the study, and had their percentage of body fat, total fat mass, and total bone-free lean mass measured annually.

The researchers found that, up until age 80, older men and women gained fat and lost lean mass each year. "This study provides a better picture of age-related changes in body composition and it's not a good picture," Ding said.

Increased fat mass and decreased lean mass may act in concert to cause a whole host of problems, the investigators write in the American Journal of Clinical Nutrition.

Moreover, when Ding's team divided the study subjects into 10 groups based on their year of birth (from 1918 to 1927), they found that, at the same age, those born later -- who therefore had spent more years during the period when obesity was increasing -- had a much higher percentage of body fat than those born earlier.

This study shows "the confluence of the effects of birth cohort and age on body composition results in bigger body size and less lean mass among the elderly." It's a recipe for disability and other ailments, the researchers warn.

SOURCE: American Journal of Clinical Nutrition, February 2007.