High baseline values of fat mass, independently of appendicular skeletal mass, predict 2-year onset of disability in elderly subjects at the high end of the functional spectrum

Background and aims: To evaluate the relation between baseline body composition and 2-year onset of functional limitation in elderly subjects at the high end of the functional spectrum. Methods: Anthropometric measurements, physical functioning as measured by a modified version of the Activities of Daily Living Scale, and baseline albumin, were evaluated in 145 men and women aged 66-78 years, free of functional limitations, selected from the general population of Verona. In each subject, total body fat mass (FM) and appendicular FFM (ASMM) were measured by dual-energy X-ray absorptiometry; the FM (FMI) and ASMM indexes (ASMMI) were also calculated by dividing each body composition variable by height squared. Results: After 2 years of follow-up, 48.2% of women and 40% of men had developed mild levels of disability, with limitations in kneeling, bending and climbing stairs. In women, but not in men, a BMI higher than 25 Kg/m(2) or values of FMI higher than the 50(th) percentile, were significantly associated with a 3 to 5 times increased risk of limitations in climbing stairs and lower body performance. In men, a trend was found between low values of ASMMI and an increased risk of limitations in kneeling and bending. After cross-tabulating categories based on the 50th percentile of ASMMI and FMI, high values of FMI, independently of ASMMI, were significantly related with higher incidence of limitation in climbing stairs in women. In women, the highest 2-year incidence of limitation in climbing stairs was found in the group of obese subjects. Conclusions: High body fat and high BMI values were associated with a greater probability of developing functional limitations 2 years later in a population of elderly subjects at the high end of the functional spectrum. Moreover, in women, high baseline values of fat mass, independently of appendicular fat-free mass, were more likely to predict the future onset of functional limitations.