Longitudinal patterns of physical activity from midlife to old age: predictors and consequences for cardiovascular disease morbidity and mortality risks

BACKGROUND/AIMS: Physical activity is important for almost all aspects of healthy ageing, including cardiovascular disease (CVD) prevention. While an age-related decline in physical activity is clear from cross-sectional studies, there are few prospective cohort studies with sufficient follow up to identify the long-term patterns of physical activity across adulthood and into old age. Subsequently, the predictors and health consequences of long-term patterns of physical activity are unclear. The primary aim of this thesis is to identify the patterns of long-term physical activity from midlife to old age and examine the predictors of such patterns and consequences in relation to cardiovascular morbidity and mortality. METHODS: This thesis uses data from the British Regional Heart Study, a prospective cohort study of men recruited in 1978-80 when they were aged 40 to 59 years. Initially, this thesis uses data from baseline up to the 20-year follow up, when men were aged 60-79 years, to examine change and trajectories of total and specific types of physical activity. Subsequent analyses explore associations between trajectories of physical activity and CVD risk factors, major stroke and coronary heart disease events, CVD mortality and all-cause mortality up until June 2016. RESULTS: One of the key findings was that total physical activity levels in old age were largely predicted by midlife physical activity. Trajectories of physical activity varied according to type; walking and recreational activity were more variable over time than total physical activity and sport/exercise. Smoking, being overweight or obese and suffering from breathlessness were associated with increased odds of following unfavourable trajectories for total and specific types of physical activity. Sociodemographic, health and behavioural factors were also associated but the direction and magnitude of associations were specific to physical activity type. Compared to a low, decreasing trajectory, light stable and moderate, increasing trajectories were associated with more favourable levels of CVD risk factors and a lower risk of all-cause mortality, CVD mortality and major coronary heart disease. There was also a dose-response relationship, suggesting that higher levels of physical activity across adulthood were more favourable. CONCLUSIONS: Physical activity levels in midlife largely determine activity levels throughout adulthood and into old age. Sport and exercise appears to be the most stable physical activity type and the strongest predictor of subsequent activity levels, whereas walking and recreational activity are more variable. A range of sociodemographic, health and behavioural factors were associated with long-term patterns of physical activity and could be used to inform intervention strategies. Although sustaining/increasing moderate levels of physical activity from midlife to old age are optimal for minimising risks of CVD and mortality, maintaining a light level of physical activity across the adult life course can also provide significant survival benefits and could be achievable for the least active.