Influence of cognitive functioning on functional status in an older population: 3- and 6-year follow-up of the Maastricht Aging Study.

Background To date, it remains unclear to what extent cognitive competence is related to a change in general functional status in older adults. Objectives To evaluate both the cross-sectional and the longitudinal relation between cognitive functioning and functional status. Methods Sensorimotor speed, memory, and executive functioning were assessed in a large population of healthy adults aged 60 years and older (n = 485) who participated in the Maastricht Aging Study. Data from the baseline (1993-1995), three-year follow-up, and six-year follow-up were used. Functional status was measured using the SF-36, which was coded into a physical and a mental component summary measure. Results After adjustment for age, sex, and educational level, a high level of cognitive functioning appeared to be associated with better functional status in the cross-sectional analysis. Longitudinal analyses demonstrated, that cognitive functioning was not a predictor of functional status three or six years later. Conclusions Thus while cognitive functioning is useful clinically for predicting the short-term functional status of an older person, it is not useful for predicting that person's long-term (> 3 years) functional status and thus the period of validity of the results of these tests in answering such questions is limited.