Interrelated factors favoring physical performance and activity in older adults from the NuAge cohort study

Contribute evidence towards the complex interrelationships of body composition, physical performance and physical activity (PA) in an older population to assist in decisions for maintaining functional capacity in older adults.

This is a cross-sectional analysis of an existing dataset in which a literature-supported model linking together the variables of interest is tested using path analysis. A proposed model with age, sex, energy intake and chronic diseases as predictors associated with body composition components, while the latter associated with physical performance and with PA acting both as a predictor and as an outcome of physical performance.

A sample of 847, community dwellers, non-diabetic older men and women from the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge Study).

Physical performance tests were reduced to two indices: strength and mobility. Muscle mass index (MMI; kg/height(2)) and % body fat were derived from DXA and bioimpedance analysis (BIA). PA was assessed by the Physical Activity Scale for the Elderly (PASE) and energy intakes were calculated from 24-hour food recalls. Data from the NuAge dataset served to test the relationships. The proposed model was evaluated using indices of fit.

Significant associations were found for MMI and % body fat with mobility (β -0.11 and -0.02, respectively), and for MMI with strength (β=0.60). PA was associated with MMI (β=0.02) and negatively with % body fat (β=-0.16), while mobility associated with PA (β=0.65). Our hypothesized model, with some paths added, fit the data: chi-square=4.64, root mean square error of approximation (RMSEA)=0.

PA has desirable associations with body composition in older adults and mobility is associated with PA. These results stress the importance of taking into account the prior level of mobility when recommending PA for this age group. This model could explain in part the complex interrelationships that occur with aging and the potential factors that could be targeted to assist older individuals in maintaining functional capacity.