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.

Background

Dietary fat intake may modify Parkinson's disease (PD) risk directly or by altering the response to environmental neurotoxicants including pesticides.

Methods

We conducted a case-control study of PD nested in the Agricultural Health Study (AHS), a cohort of pesticide applicators and spouses. We evaluated diet and pesticide use before diagnosis in 89 PD cases, confirmed by movement disorder specialists, or a corresponding date in 336 frequency-matched controls. Associations were evaluated using multivariate logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

Results

In the AHS, PD was inversely associated with N-3 polyunsaturated fatty acids (PUFAs) (OR 0.4, 95% CI 0.2-0.8 for highest vs. lowest tertile) and the N-3 precursor α-linolenic acid (0.4, 0.2-0.8). In a meta-analysis of nine studies, including the present one, PD was inversely associated with α-linolenic acid (0.81, 0.68-0.96). In the AHS, associations of PD with the pesticides paraquat and rotenone were modified by fat intake. The OR for paraquat was 4.2 (1.5-12) in individuals with PUFA intake below the median but 1.2 (0.4-3.4) in those with higher intake (p-interaction = 0.10). The OR for rotenone was 5.8 (2.3-15) in those with saturated fat intake above the median but 1.5 (0.5-4.2) in those with lower intake (p-interaction = 0.02).

Conclusions

PUFA intake was consistently associated with lower PD risk, and dietary fats modified the association of PD risk with pesticide exposure. If confirmed, these findings suggest that a diet high in PUFAs and low in saturated fats might reduce risk of PD.