Study objective: To investigate age, period, and cohort effects on functional status.
Design: A prospective cohort study with measurements in 1981, 1990, and 1996.
Setting: Three municipalities in north east Finland.
Participants: A regionally representative sample of 19 to 63 year old men and women was drawn from the census data in 1979, of which 758 men and 1033 women initially aged 39-63 years entered the study in 1980 and completed the follow up in 1996 (90.9% of the alive cohort).
Measurements and main results: Functional status was determined based on self estimated disabilities (difficulties or not able) to walk 2 km, climb several flights of stairs, and run 100 m. The age adjusted odds of disability in stair climbing and running were lower among the men and the women in 1990 and 1996 than among the men and the women in 1981. There was a declining trend in the odds of disability with succeeding birth cohorts among both the men (odds ratios (OR) 0.79 and 95% confidence intervals (CI) 0.70 to 0.88 for stair climbing and OR 0.88 and 95% CI 0.78 to 0.98 for running) and the women (OR 0.85 and 95% CI 0.77 to 0.93 for stair climbing and OR 0.85 and 95% CI 0.76 to 0.94 for running). No statistically significant differences in walking disability were found between the study periods or the study cohorts.
Conclusions: The findings depict an improved time trend in functional status in the study population, with implications for future health and social care planning.