Associations of occupational physical activity with incident cardiovascular disease and mortality in Chinese adults

In contrast to leisure-time physical activity, occupational physical activity (OPA) has not consistently been associated with health benefits, with most evidence originating from European high-income countries. We therefore investigated the associations of OPA with incident cardiovascular disease and mortality in a Chinese population, and examined potential effect modification by modifiable risk factors. This study was using data from a nationwide population-based cohort, the China Cardiometabolic Disease and Cancer Cohort Study. During the baseline survey (2011-12), self-reported OPA level was measured with four response categories, a modifiable risk score was calculated (including body mass index, waist circumference, blood pressure, glycemic status, LDL level, smoking status, drink, diet, leisure-time physical activity, and sleep duration). Information on incident acute myocardial infraction and stroke and all-cause mortality was actively collected till 2021. During a median of 10.2 years follow-up, 1,654 incident cardiovascular cases and 1,704 death events were documented among 49,007 participants (mean age 51.4 years, 53.2% women). Compared to individuals with low OPA, higher OPA was consistently associated with elevated cardiovascular risk, with the HR (95%CI) 1.14 (0.98, 1.33) for high and 1.26 (1.07, 1.48) for very high OPA. Among female workers and workers with pre-existing cardiovascular disease or hypertension, very high OPA increased cardiovascular disease risk by 43–44%. In addition, per one increment of total modifiable risk score (indicating a more favorable profile) was associated with 18%-23% lower risks of incident cardiovascular disease among different OPA categories. Compared to those with low OPA and favorable modifiable risk profile, a more than threefold increased risk of incident cardiovascular disease was observed for those with an unfavorable modifiable risk profile and high OPA (HR 3.21, [2.37, 4.34]) and for those with an unfavorable modifiable risk profile and very high OPA (HR 3.14, [2.30, 4.30]). Similar patterns were observed regarding mortality outcome. Higher OPA levels were associated with elevated cardiovascular and mortality risk, especially among women and workers with prevalent cardiovascular disease or hypertension, and a favorable modifiable risk profile was associated with lower risk across all OPA levels.