Abstract P386: Pregnancy-related Risk Factors May Signal Additional Risk For Future Cardiovascular Disease

Abstract

Introduction: Emerging data suggest that pregnancy may be a window on the future of women’s cardiovascular health. Cardiovascular disease (CVD) guidelines recommend using the Pooled Cohort Equation (PCE) to assess 10-year CVD risk based on traditional risk factors. Less is known about the role of pregnancy-related factors, such as a history of small for gestational age (SGA) infants or breastfeeding, and the risk of CVD events in addition to the PCE. Hypothesis: We hypothesize that pregnancy-related complications and breastfeeding can affect the risk of future CVD risk in addition to traditional risk factors currently accounted for by the PCE. Methods: Using NHANES 1999-2006, a weighted sample of 3,913 women (representing 27,102,057 women in the US population), ages 40-79, with a history of pregnancy, but no prior CVD, was identified. Variables for SGA infants and breastfeeding were abstracted along with traditional risk factors. Less than 5% of women were missing data on these variables. CVD outcomes were defined as a composite of (1) CVD death and (2) surrogates for CVD death, in which diabetes or hypertension were a secondary cause of death. CVD outcomes and survival time were obtained from the NHANES Linked Mortality File. The PCE was used to estimate 10-year CVD risk. Bivariate and survival analyses using Cox proportional hazards models adjusting for PCE risk score were performed. For survival analysis, the cause-specific hazard function was estimated considering the time of death as censoring for women dying from causes other than CVD outcomes, as well as the time of follow-up for women that did not present the death event. Results: Among the sample, 504 (11.8%) women had a SGA infant and 2133 (54.5%) reported a history of breastfeeding. 198 (5.1%) women had the composite CVD death outcome. CVD outcomes were lower in women with a history of breastfeeding (97 of 2133) compared to those who did not breastfeed (96 of 1629). (2.6% vs. 4.2%, p=0.002) The opposite relationship was observed for women with a history of SGA infant (4.2% (29 of 504) vs. 3.2% (161 of 3232), p=0.2). PCE scores were associated with breastfeeding and SGA, potentially confounding those effects. Survival analyses, adjusting for continuous PCE risk scores, showed an inverse association of breastfeeding and CVD outcomes (HR 0.7, 95% CI 0.5 to 1.0) and a positive association of history of SGA infant and CVD outcomes. (HR 1.4, 95% CI 0.8 to 2.2) Conclusion: Specific pregnancy-related complications and breastfeeding may provide additional, relevant information about the risk of CVD risk events beyond traditional risk factors. While further research is needed to incorporate pregnancy outcomes into risk prediction models, it may be helpful for clinicians to counsel women about the potential impact of pregnancy-related factors and breastfeeding on future cardiovascular health.