Early adulthood determinants of mid-life leisure-time physical inactivity stability and change: Findings from a prospective birth cohort

Objectives Physical inactivity is highly prevalent. Knowledge is needed of influences on inactive lifestyles. We aimed to establish whether early adult factors predict subsequent inactivity patterns in mid-adulthood. Design Leisure-time inactivity (activity frequency < 1/week) was assessed at 33y and 50y in the 1958 British Birth cohort (N = 12,271). Methods We assessed associations of early adult (23–33y) physical status, mental function, social, family and neighbourhood circumstances with four 33–50y patterns (never inactive, persistently inactive, deteriorating or improving) using multinomial logistic regression with and without adjustment for childhood factors (e.g. social class). Results Inactivity prevalence was similar at 33y and 50y (∼31%), but 17% deteriorated and 18% improved with age. Factors associated with persistent vs never inactive were: limiting illness (relative risk ratio (RRR):1.21(1.04,1.42) per number of ages exposed (0,1 or 2 times across ages 23y and 33y), obesity (1.33(1.16,1.54) per number of ages exposed), height (0.93(0.89,0.98) per 5 cm), depression (1.32(1.19,1.47) per number of ages exposed); education (1.28(1.20,1.38) per decrease on 5-point scale) and neighbourhood (1.59(1.37,1.86) in ‘industrial/local authority housing areas’ and 1.33(1.12,1.58) in ‘growth/metropolitan inner areas’ vs ‘suburbs, service, rural or seaside areas’). Associations were broadly similar for inactivity deterioration. Industrial/local authority housing areas (0.75(0.61,0.91)) and longer obesity exposure (0.78(0.64,0.95)) were associated with lower RRRs for improvement. Number of children was associated with improvement, although associations varied by age. Associations remained after adjustment for childhood factors. Conclusions Several early adult factors are associated with inactivity persistence and deterioration; fewer with improvement. Obesity duration and neighbourhood lived in during young adulthood had long-lasting associations with inactivity patterns in mid-life.