Can allostatic load in pregnancy explain the association between race and subsequent cardiovascular disease risk: A cohort study.

Objective: To assess the relationship between allostatic load, a measure of cumulative chronic stress in early pregnancy and cardiovascular disease risk, 2-7 years postpartum, and pathways contributing to racial disparities in cardiovascular disease risk.

Design: Secondary analysis of a prospective cohort study.

Setting Multicenter Population: Pregnant women.

Methods: Our primary exposure was high allostatic load in the first trimester, defined as at least 4 of 12 biomarkers (systolic blood pressure, diastolic blood pressure, body mass index, cholesterol, low-density lipoprotein, high-density lipoprotein, high-sensitivity C-reactive protein, triglycerides, insulin, glucose, creatinine and albumin) in the unfavourable quartile. Logistic regression was used to test the association between high allostatic load and main outcome adjusted for confounders: time from index pregnancy and follow up, age, education, smoking, gravidity, bleeding in the first trimester, index adverse pregnancy outcomes, and health insurance. Each main outcome component and allostatic load were analysed secondarily. Mediation and moderation analyses assessed the role of high allostatic load in racial disparities of cardiovascular disease risk.

Main Outcome Measure: Incident cardiovascular disease risk: hypertension, or metabolic disorders.

Results: Cardiovascular disease risk was identified in 1462/4022 individuals (hypertension: 36.6%, metabolic disorder: 15.4%). After adjustment, allostatic load was associated with cardiovascular disease risk (adjusted odds ratio [aOR] 2.0, 95% CI 1.8-2.3), hypertension (aOR 2.1, 95% CI 1.8-2.4) and metabolic disorder (aOR 1.7, 95% CI 1.5-2.1). Allostatic load was a partial mediator between race and cardiovascular disease risk. Race did not significantly moderate this relationship.

Conclusions: High allostatic load during pregnancy is associated with cardiovascular disease risk. The relationships between stress, subsequent cardiovascular risk and race warrant further study.