Physical Activity Energy Expenditure and Sarcopenia in Black South African Urban Women

Background: Black women are believed to be genetically less predisposed to age-related sarcopenia. The objective of this study was to investigate lifestyle factors associated with sarcopenia in black South African (SA) urban women. Methods: In a cross-sectional study, 247 women (mean age 57 y) were randomly selected. Anthropometric and sociodemographic variables, dietary intakes, and physical activity were measured. Activity was also measured by combined accelerometery/heart rate monitoring (ActiHeart), and HIV status was tested. Dual energy x-ray absorptiometry was used to measure appendicular skeletal mass (ASM). Sarcopenia was defined according to a recently derived SA cutpoint of ASM index (ASM/height squared) < 4.94 kg/m(2). Results: In total, 8.9% of the women were sarcopenic, decreasing to 8.1% after exclusion of participants who were HIV positive. In multiple regressions with ASM index, grip strength, and gait speed, respectively, as dependent variables, only activity energy expenditure (beta =.27) was significantly associated with ASM index. Age (beta = -.50) and activity energy expenditure (beta = .17) were significantly associated with gait speed. Age (beta = -.11) and lean mass (beta = .21) were significantly associated with handgrip strength. Conclusions: Sarcopenia was prevalent among these SA women and was associated with low physical activity energy expenditure.