Physical Activity And The Risk Of Cardiovascular Disease Incidence And Mortality In The UK Biobank

Physical activity (PA) is thought to decrease the risk of cardiovascular disease (CVD) incidence and mortality. However, it is unclear whether there is a difference in the strength of the association of PA with the risk of developing incident CVD when compared to CVD mortality. Further, CVD risk associations among different ways of measuring PA are not well understood. PURPOSE: to determine the association between PA and CVD incidence and mortality using a common self-reported measure of moderate to vigorous PA, and an accelerometry-calibrated self-reported measure of PA (ACPA), expressed as total energy expended in PA, within the UK Biobank cohort. METHODS: a prospective cohort study of 310,933 UK Biobank participants free of CVD at baseline was conducted. Physical activity was assessed using self-reported PA with the International Physical Activity Questionnaire and ACPA. Incident CVD and CVD mortality were determined through ICD-10 codes and data linkage through death and hospital records. Cox proportional hazard models were used to estimate the risk of CVD incidence and mortality between quartiles of PA after adjusting for known confounders. RESULTS: There were 86,396 incident cases of CVD and 4,557 CVD deaths during the follow-up period. ACPA was associated with lower CVD incidence (hazard ratio (HR) for most vs least active quartile, 0.94 [95% CI, 0.92-0.96]) but no risk reduction was seen for self-reported PA. For mortality, the only CVD risk reduction for self-reported PA was observed in the third quartile (HR, 0.90 [95% CI, 0.82-0.98]), however, a stronger and dose-response relationship was found for ACPA (HR for most vs least active quartile, 0.81 [95% CI, 0.73-0.89]). CONCLUSION: PA was associated with a reduced risk of both CVD incidence and mortality when measured with ACPA. When using the self-reported PA metric, no association was observed for CVD incidence and a weaker association was observed for mortality. The risk reduction for PA and CVD was stronger for mortality than incidence for both PA measures suggesting that PA is somewhat protective against developing CVD but much more protective against the risk of dying from it.