Physical Activity and Ischemic Heart Disease Risk: A Prospective Cohort Study Among Chinese Adults.

Background: Type-specific physical activity (PA) may be associated with different risks of ischemic heart disease (IHD), but few large studies have examined this. This study aimed to assess the incidence and dose-response relationships between total PA and 4 different types of PA and IHD risk in Chinese adults.

Methods: The prospective China Kadoorie Biobank enrolled 35,508 adults from Qingdao from 2004 to 2008, including 33,342 IHD-free participants in this analysis. PA was collected through a self-report questionnaire, calculating metabolic equivalents of task-hours per day based on duration and frequency. Cox regression analysis was used to assess the association between PA and IHD risk.

Results: During a median 9.2 years of follow-up, 2712 incident IHD cases were recorded. Total, occupational, commuting, and leisure-time PAs were inversely associated with IHD risk. Compared with the participants in the bottom quintiles of PA, the participants in the top quintiles of total PA, occupational PA, commuting PA, and leisure-time PA had 43% (hazard ratio [HR] = 0.57; 95% CI, 0.49-0.66), 38% (HR = 0.62; 95% CI, 0.50-0.75), 38% (HR = 0.62; 95% CI, 0.44-0.87), and 21% (HR = 0.79; 95% CI, 0.67-0.95) lower IHD risk, respectively. A negative association between household PA and IHD risk was found only in males (HR = 0.83; 95% CI, 0.70-0.98). The restricted cubic spline  regression analysis revealed a linear relationship between total PA and IHD risk (P for nonlinear = .5687).

Conclusion: Among Chinese adults, higher total, occupational, commuting, and leisure-time PA was associated with significantly lower risks of IHD, and increased household PA could reduce IHD risk in males.