Influence of Socioeconomic Status on the Association Between Pregnancy Complications and Premature Coronary Artery Disease: Linking Three Cohorts

Background: We hypothesized that there is an influence of socioeconomic status (SES) on association between pregnancy complications and premature coronary artery disease (PCAD) risk. Materials and Methods: This project involved a data linkage approach merging three databases of South Australian cohorts using retrospective, age-matched case–control study design. Cases (n = 721), that is, women aged <60 years from Coronary Angiogram Database of South Australia (CADOSA) were linked to South Australian Perinatal Statistics Collection (SAPSC) to ascertain prior pregnancy outcomes and SES. Controls (n = 194) were selected from North West Adelaide Health Study (NWAHS), comprising women who were healthy or had health conditions unrelated to CAD, age matched to CADOSA (–5 years), and linked to SAPSC to determine prior pregnancy outcomes and SES. This project performed comparative analysis of SES using socioeconomic indexes for areas–index of relative socioeconomic advantage and disadvantage (SEIFA-IRSAD) scores across three databases. Results: Findings revealed that SEIFA-IRSAD scores at the time of pregnancy (p-value = 0.005) and increase in SEIFA-IRSAD scores over time (p-value = 0.040) were significantly associated with PCAD. In addition, when models were adjusted for SEIFA-IRSAD scores at the time of pregnancy and age, risk factors including placenta-mediated pregnancy complications such as preterm birth (odds ratio [OR] = 4.77, 95% confidence interval [CI]: 1.74–13.03) and history of a miscarriage (OR = 2.14, 95% CI: 1.02–4.49), and cardiovascular disease (CVD) risk factors including smoking (OR = 8.60, 95% CI: 3.25–22.75) were significantly associated with PCAD. When the model was adjusted for change in SEIFA-IRSAD scores (from CADOSA/NWAHS to SAPSC) and age, pregnancy-mediated pregnancy complications including preterm birth (OR = 4.40, 95% CI: 1.61–12.05) and history of a miscarriage (OR = 2.09, 95% CI: 1.00–4.35), and CVD risk factor smoking (OR = 8.75, 95% CI: 3.32–23.07) were significantly associated with PCAD. Conclusion: SES at the time of pregnancy and change in SES were not associated with PCAD risk.