Impact of hypertension on the dose-response association between physical activity and stroke: A cohort study.

BackgroundThere is a strong dose-response relationship between regular physical activity (PA) and stroke risk. However, this relationship is attenuated in the presence of cardiovascular risk. This study aimed to compare the dose-response relationship between PA and stroke between normo- and hypertensive individuals. MethodsA cohort study including 139,930 individuals was performed (median follow up: 6.75 years). Participants were stratified at baseline as hypertensive or normotensive and were categorised into quartiles of lowest (Q1) to highest (Q4) moderate-to-vigorous (MV), self-reported PA. Primary outcome was stroke. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals. The main analyses were stratified on baseline blood pressure and adjusted for confounders. Additionally, hypertensives were stratified into medicated or not medicated. ResultsCompared to Q1, adjusted HRs were 0.87 (0.69-1.10, P=0.23) for Q2, 0.75 (0.59-0.95, P=0.02) for Q3, and 0.94 (0.74-1.20, P=0.64) for Q4 in the total population. In the stratified analyses, HRs for individuals with normotension were 0.79 (0.50-1.25, P=0.32), 0.75 (0.48-1.18, P=0.22), 0.97 (0.62-1.51, P=0.90) for MVPA Q2 to Q4, respectively. In hypertensive individuals, HRs compared to Q1 were 0.89 (0.68-1.17, P=0.41), 0.74 (0.56-0.98, P=0.03), 0.92 (0.69-1.23, P=0.56) for Q2-Q4, respectively. There was no significant interaction between PA and hypertensive status. A smaller benefit of MVPA in medicated hypertensives compared to non-medicated was observed, however the dose-response association was similar. ConclusionMVPA reduces stroke risk in the total population (Q3), which is not affected by the presence of hypertension. Use of anti-hypertensive medication may interfere with the impact of MVPA on stroke risk. Novelty and RelevanceO_ST_ABSWhat is new?C_ST_ABSPresence of cardiovascular disease or cardiovascular disease risk factors may alter the dose-response relationship between regular physical activity and major adverse cardiovascular events (MACE) and mortality. No previous study has investigated whether hypertension per se alters the dose-response relationship between regular moderate-to-vigorous physical activity (MVPA) and stroke risk. What is relevant?This large cohort study demonstrates the importance of regular MVPA on stroke risk reduction particularly in individuals with hypertension. Furthermore, this study provides preliminary indication that the use of antihypertensive medication may alter this association. Clinical/Pathophysiological implications?The presence of hypertension does not alter the dose-response association between MVPA and stroke. Importantly, this highlights that MVPA is beneficial in reducing the risk of stroke, even in individuals diagnosed with hypertension. Although this cohort study cannot make solid conclusions on the influence of antihypertensive medication, this study reinforces the importance of regular physical activity on the clinical outcome of stroke.