Allostatic load partially mediates the association between number of stressful life events and cardiometabolic multimorbidity: A nationally representative cross sectional study from CHARLS

BACKGROUND: Stressful life events are independent psychological risk factor for diabetes and cardiovascular disease, yet studies on cardiometabolic multimorbidity (CMM) are scarce. This study aimed to examine the effects of stressful life events and their accumulation on the prevalence of CMM, as well as the mediating role of allostatic load in the association between accumulated stressful life events and CMM. METHODS: A total of 7493 participants from Wave 3 (2015) of the China Health and Retirement Longitudinal Study (CHARLS) were included. Stressful life events were assessed using five simple questions. CMM, defined as having two or more of cardiometabolic diseases, including diabetes, heart disease and stroke, was obtained through self-reports. RESULTS: The prevalence of CMM increased with the number of stressful life events, ranging from 5.73 % for one stressful life event to 6.61 % for two or more. In the fully adjusted model, the odds ratios (95 % confidence interval) for CMM were 1.49 (1.01-2.20) for participants experiencing marital problems and 1.93 (1.45-2.56) for those with functional disability. Compared with no stressful life events, an increasing number of stressful life events was associated with a higher risk of CMM (P-trend <0.001). The mediation analysis results demonstrated that allostatic load was a significant mediator of the association between accumulated stressful life events and CMM, accounting for a mediated proportion of 16.7 %. CONCLUSIONS: In the general population, the presence of specific and cumulative stressful life events is associated with an increased prevalence of CMM, and allostatic load plays a crucial mediation effect.