Contribution of serum lipids as effect modifiers to a relationship between mean arterial pressure and coronary heart disease in Chinese rural population: the Henan Rural Cohort Study

OBJECTIVES: The aim of this study was to evaluate the relationship between mean arterial pressure (MAP) and coronary heart disease (CHD) in Chinese rural population. In addition, we hypothesised that this relationship might be mediated by some degree of serum lipids. DESIGN: This is a cross-sectional study. SETTING: The participants were from the Henan Rural Cohort Study, initiated in five rural areas (Tongxu county of Kaifeng city, Yima county of Sanmenxia city, Suiping county of Zhumadian city, Xinxiang county of Xinxiang city and Yuzhou county of Xuchang city) in Henan Province, China, during July 2015 and September 2017. PARTICIPANTS: The study included 39 020 subjects aged 18–79 years as current research population. OUTCOME MEASURES: Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using an electronic sphygmomanometer. MAP was calculated by one-third SBP plus two-thirds DBP. The study used restricted cubic splines and logistic regression models to evaluate the ORs and 95% CIs. Mediation analysis using bootstrap was performed to examine the contribution of serum lipids to MAP-related CHD. RESULTS: The adjusted OR (95% CI) for the highest MAP quartile with the risk of CHD was 1.45 (1.24 to 1.69) compared with the lowest quartile. Simultaneously, each 1-SD increment in MAP was significantly associated with a 12% increased risk of CHD. A linear dose–response relationship between MAP and CHD was found (p value for non-linear=0.1169) in the fully adjusted model. We further reported that 36.07% of proportion explained risk of CHD was mediated through serum lipids. CONCLUSIONS: Increased MAP was a significant marker of CHD in Chinese rural population. Meanwhile, the relationship was mediated by some degree of serum lipids, and triglyceride was the strongest mediator. TRIAL REGISTRATION NUMBER: Henan Rural Cohort study has been registered at Chinese Clinical Trial Register (ChiCTR-OOC-15006699) and the stage it relates to is Post-results.