Comorbidity (COM) is an important issue in aging. Cardiovascular disease (CVD) and osteoarthritis separately and together may modify the trajectories of functional decline. This analysis examines whether specific and unrelated COMs influence functional change differently and vary by gender.
A cohort study of 1,789 (aged 60 years and older) Mexican Americans was followed annually for up to 10 years. We created four groups of COM (CVD alone, lower body osteoarthritis alone [OA], neither, or both). We employed mixed effects Poisson models with Instrumental Activities of Daily Living (IADL) as the outcome. We tested whether the association between COM and decline in functional status differed by gender.
IADL impairments in those with CVD, OA, or both were significantly higher at baseline and increased more rapidly over time compared to those with neither condition. Compared to women with no COM, the number of IADL impairments in women with CVD alone were 1.36 times greater, with OA were 1.35 times greater, and both conditions were 1.26 times greater. Compared to men with no COM, IADL impairments in men with CVD alone were 1.15 times greater, OA alone were 1.12 times greater, and both were 1.26 times greater.
Over time, the influence of COM on functional decline differs by specific combinations of COM and by gender. Aggregate COM scales obscure the biological and temporal heterogeneity in the effects of COM. Time-dependent-specific COMs better assess the development of impairment. Women experience a higher burden of functional impairment due to COM than men.