Lifetime breastfeeding and mortality among parous women in the Mexican Teacher's Cohort.

Abstract

Objective: To assess the relationship between lifetime breastfeeding and all-cause and cause-specific mortality in Mexican women.

Methods: We used prospective data of 88 597 women from the Mexican Teachers' Cohort. Hazard ratios (HRs) were estimated from Cox regression models for total mortality, and a competing risk model was used for cause-specific mortality, adjusted for childhood/adolescence socioeconomic and lifestyle factors, age at first birth, and number of births. A dose-response relation was assessed using smoothed splines.

Results: Participants, on average, breastfed for 6 months per birth, with a mean total breastfeeding duration of 13 months. After a mean follow-up of 11 years, 1556 deaths were found. Compared with parous women who did not breastfeed, all-cause mortality was lower for women who breastfed (<6 months: 0.78, 95% confidence interval [CI] 0.67-0.91; for 6-12 months: 0.76, 95% CI 0.64-0.90; for 12-24 months: 0.73, 95% CI 0.62-0.86; and for >24 months: 0.77, 95% CI 0.64-0.91). The dose-response relationship between breastfeeding and all-cause mortality was non-linear (P = 0.023). This trend was consistent when accounting for single live births and excluding women with gestational conditions. Those who breastfed >6 months had lower risk of cardiovascular and breast cancer-specific mortality.

Conclusion: Breastfeeding was associated with reduced all-cause, cardiometabolic, and breast cancer mortality in Mexican women. The findings support the need for comprehensive policies to support breastfeeding, considering the potential for significant public health benefits. Additionally, the study highlighted a substantial gap in breastfeeding practices in Mexico, with average durations far below international recommendations.