Physical functioning and use of health services in a young and old sample. The influence of fatigue

The purpose was to analyse 1) whether fatigue is related to physical functioning and utilization of health services at one-year follow-up in a young and old sample and 2) to compare the results of two different measures of fatigue.

The study is a longitudinal cohort study based on 182 young (age 20-35) and 199 older (age 70-85) community-dwelling individuals recruited from nine general practitioners in Aarhus, Denmark. Physical functioning was measured by the physical health scale from the SF-12-questionnaire. Data on health care utilization were extracted from the county's central register during one year. Fatigue was measured as Vitality-Tiredness by a question from the SF-12 questionnaire and Mobility-Tiredness by the Avlund Mobility-Tiredness Scale on fatigue in six daily activities.

The predictive value of the two measures varied by the age of the participants. The Vitality-Tiredness Scale was related to the outcome measures in both samples, while the Mobility-Tiredness Scale was only predictive in the old population. In the young sample the associations were attenuated by the covariates, while the estimates in the old sample remained strong and significant in the adjusted analyses.

Fatigue is related to subsequent physical functioning and use of health services at one year follow-up, both in young and old individuals.