Objective. To estimate the effects of physical activity (PA) and obesity on the cumulative incidence of disability on the basic activities of daily living in the elderly.

Materials and methods. Longitudinal study. We selected 2477 participants aged 65-74 years from the impact evaluation study of a non-contributory pension program in Mexico. Participants were without disability at baseline. Katz index was used to assess disability both at baseline and follow-up. PA, body mass index, and covariates were measured at baseline.

Results. After 14-months of follow-up, the cumulative incidence of disability reached 10.1%. High PA was found to reduce disability risk (OR=0.64; 95%CI [0.43-0.95]), and the association between obesity and disability was marginally significant (OR=1.36; 95%CI [0.96-1.95]).

Conclusions. There is a need to perform a functional assessment of older adults in primary care to identify patients with functional dependence , and to promote physical activity to maintain muscle mass and thus reduce the incidence of disability.