Combined effects of obesity and objectively-measured daily physical activity on the risk of hypertension in middle-aged Japanese men: A 4-year prospective cohort study

Background: The combined effects of physical inactivity and obesity on hypertension have been recognized; however, previous studies evaluated physical activity using questionnaires. We aimed to examine the effects of physical activity, measured using an accelerometer, and obesity on hypertension onset. Methods: At baseline, 426 middle-aged Japanese men who were not on antihypertensive medications were included. Physical activity was measured for 7 consecutive days using an accelerometer. Mean daily moderate to vigorous physical activity (MVPA) and step count (SC) were calculated. Low MVPA and low SC were each defined as the first tertile. Obesity was defined as >= 25 kg/m2 of body mass index. The onset of hypertension was defined as receiving antihypertensive agents during the 4-year follow-up. The combined effects of obesity and physical inactivity on hypertension were examined using Cox regression analysis. Potential confounders included age, smoking, alcohol consumption, daily salt intake, dyslipidemia, diabetes mellitus, and systolic and diastolic blood pressures. Results: Cox regression analysis revealed that both obesity and low MVPA predicted hypertension in patients, independent of confounders (hazard ratio [HR]: 2.64, 95% confidence interval [CI]: 1.08-6.42, p = 0.033), unlike obesity alone (HR: 1.50, 95% CI: 0.50-3.26, p = 0.590). Stratification by obesity and SC revealed similar hypertension risks among the two groups (Obesity with low SC [HR: 2.10, 95% CI 0.88-5.24, p = 0.089]; Obesity without low SC [HR: 1.72, 95% CI 0.93-4.01, p = 0.082]). Conclusions: Here, findings suggest that the coexistence of obesity and decreased MVPA may increase the risk of hypertension onset. (C) 2019 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.