History of Breastfeeding and Stroke Prevalence Among Parous Females: Findings from the National Health and Nutrition Examination Survey, 1999-2012

Introduction: Given the known relationships between breastfeeding and hypertension, and between hypertension and stroke, we examined the association between breastfeeding a child and stroke later in life. We hypothesized a history of breastfeeding is associated with lower prevalence of stroke. Methods: Our study population included parous females 20 years and older. Potential confounders included family income-to-poverty ratio, education, smoking status, parity, and age at first live birth. Potential effect measure modifiers included race/ethnicity and age at survey. Multivariable logistic regression models were used to estimate crude and adjusted prevalence odds ratios (ORs) and 95% confidence intervals (CIs) for the association between breastfeeding and stroke. Results: The odds of stroke among those who ever breastfed were lower than those who never breastfed (OR = 0.68, 95% CI: 0.55-0.86; p < 0.01). Adjusting for education decreased the strength of the association (OR = 0.80, 95% CI: 0.63-1.01; p = 0.06). In analyses stratified by age, the inverse association between breastfeeding status was significant among those ages 20-64 years (OR = 0.69, 95% CI: 0.47-1.00) but not among those 65 years and older (OR = 0.99, 95% CI: 0.73-1.34). Conclusions: Ever breastfeeding a child was associated with lower prevalence of stroke in a nationally representative U.S. sample of parous females 20 years and older. Results were strongest among those < 65 years old.