Trajectories of mobility limitations over 24 years and their characterization by shift work and leisure-time physical activity in midlife

Background We aimed to investigate trajectories of mobility limitations (MLs) over a period of 24 years. In addition, we aimed to study how shift work and leisure-time physical activity (LTPA) in midlife predict assignment to MLs trajectories separately for those retired on statutory pensions (SPs) and on disability pensions (DPs). Methods Subjects who responded MLs questionnaires (1985–2009, N = 3048) in Finnish Longitudinal Study on Aging Municipal Employees were included in this prospective cohort study. LTPA and shift work were measured during baseline. International Classification of Functioning was used to code MLs. Growth mixture modeling was used to identify the trajectories of MLs. Odds ratio (OR) and their 95% Confidence interval (CI) were assessed by using multinomial logistic regression. Results We identified four trajectories of MLs, namely low persistent, low increasing, high decreasing and high persistent. Among the SP recipients, shift work with night shifts was associated with an increased risk (adjusted OR 1.49; 95% CI 1.03–2.14) of belonging to the high persistent MLs trajectory. The inactive LTPA (SP: OR 5.99, 95% CI 3.39–10.58, DP: OR 6.81, 95% CI 2.52–18.43) was similarly associated with high persistent MLs trajectory. Conclusion Nearly two-thirds of the people retired due to disability belonged to high MLs trajectory. High persistent MLs trajectory was associated with physical inactivity in midlife among those retired on SP and on DP. Shift work with night shift predicted high persistent MLs in SP strata. Active involvement in LTPA during midlife could be beneficial to spend MLs free later life.