Decline and Peripheral Redistribution of Fat Mass in Old Age - A Four-Year Prospective Study in 3018 Older Community-Living Adults.

Abstract

It is widely recognized that fat will accumulate with ageing and is more prominent centrally. However, there were studies reported that fat might not gain either centrally or generally with ageing. The baseline, 2-year and 4-year total body fat mas, trunk fat mass and percentage fat mass, were measured by DXA in 3018 community-living Chinese older than 65 years. The respective 4-year trajectories of adiposity were analyzed by repeated measure ANOVA p-for-trend test. There was a trend of increase in total body fat mass in men and a decreasing trend in women but neither reached statistical significance. However, there was a significant increase in percent fat mass in both genders. Fat mass was relatively stable in the 2 young-old groups but it declined in the oldest group, aged 75 years or above. (men, p=0.017; women, p<0.001). On the contrary, a corresponding rise of percent fat mass was observed, which was steeper in the 2 younger age groups but did not change in the oldest group. For trunk fat mass, there was a statistically significant decreasing trend in women (p < 0.001) but it remained static in men (p = 0.092). The fat mass in upper limbs of both genders did not change but for the lower limbs, there was a statistically significant increase in both men (p < 0.001) and women (p < 0.02). Absolute total body fat mass does not accumulate in old age and in the contrary, in the oldest old group (75 years or above), it declined instead. With ageing, fat will redistribute from the central region to the lower limbs.