Serum cotinine and adverse cardiovascular outcomes: a cross-sectional secondary analysis of the nuMoM2b Heart Health Study

Objective: Women with adverse pregnancy outcomes (APOs) have increased risks for cardiovascular disease. Smoking is a source of confounding that may be difficult to assess by self-report. We aimed to estimate odds of cardiovascular outcomes by smoking status using serum cotinine versus self-report and to assess whether the association between APOs and cardiovascular outcomes varies by smoking status. Study Design: We conducted a cross-sectional study of the nuMoM2b Heart Health Study wherein women attended an in-person visit 2-7 years following their first pregnancy. The exposure was smoking status, determined by self-report and by serum cotinine levels. Outcomes included incident chronic hypertension, metabolic syndrome, and dyslipidemia. Multivariable logistic regression estimated odds ratios for each outcome by smoking status. Results: Of the 4,392 women with serum cotinine measured, 3,610 were categorized as nonsmokers, 62 as having secondhand smoke exposure, and 720 as smokers. After adjustment for APOs, smoking defined by serum cotinine levels was associated with metabolic syndrome (adjusted odds ratio (aOR) 1.52, 95% confidence interval (CI) 1.21, 1.91) and dyslipidemia (aOR 1.28, 95% CI 1.01, 1.62). When stratified by nicotine exposure, nonsmokers with an APO in their index pregnancy had higher odds of stage 1 (aOR 1.64, 95% CI 1.32, 2.03) and stage 2 hypertension (aOR 2.92, 95% CI 2.17, 3.93), metabolic syndrome (aOR 1.76, 95% CI 1.42, 2.18), and dyslipidemia (aOR 1.55, 95% CI 1.25, 1.91) relative to women with no APO. Similar findings were obtained using self-report to define smoking exposure. Conclusion: Smoking and APOs are independently associated with subsequent cardiovascular outcomes in reproductive-age women. Smoking is associated with metabolic syndrome and dyslipidemia, whether smoking status is obtained by serum cotinine or self-report. Among nonsmokers, a history of APO is associated with hypertension, metabolic syndrome, and dyslipidemia compared to women without APOs.