Breastfeeding reduced CHD risk in Chinese parous women
Breastfeeding and the Risk of Maternal Cardiovascular Disease: A Prospective Study of 300 000 Chinese Women
Peters S.A.E, Yang L, Guo Y, et al. - J Am Heart Assoc 2017 [Epub ahead of print]Background
During pregnancy, substantial changes occur regarding the maternal metabolic system. These changes may disappear more quickly and completely with breastfeeding [1-3]. Moreover, longer breastfeeding has been beneficially associated with metabolic syndrome, hypertension and diabetes mellitus in later life [4-6]. However, there are many discrepancies between studies concerning this topic and breastfeeding practices differ within and between countries, leading to inconsistency of results. Interestingly, breastfeeding practices are almost universal in China and many women continue breastfeeding for long durations, thereby significantly differ from Western countries [7].
This analysis examined the relationship between breastfeeding and the risk of several major cardiovascular diseases (CVD) among 289,573 women (average age 51yrs) from the prospective China Kadoorie Biobank study. 97% of these women had ever breastfed and 91% breastfed each child for at least 6 months. Median duration of breastfeeding per child was 12 months and median follow-up was 8.1 years.
Main results
- Whereas there were no differences in CVD risk between nulliparous and parous women who did not breastfed, parous women who had breastfed were at significantly lower risk of major CVD and its main components than parous women who had never breastfed (HR major CVD 0.88, 95% CI 0.80-0.97, HR CHD 0.91, 95% CI 0.84-0.99, HR stroke 0.92, 95% CI 0.85-0.99, HR ischemic stroke 0.88, 95% CI 0.79-0.97).
- Risks were not different between regions, birth cohorts, level of education, smoking status, BMI categories, SBP categories and diabetes mellitus status.
- Compared to women who had never breastfed, women who had breastfed for a duration between 0-6 months, 6-12 months, 12-18 months, 18-24 months or >24 months had a 1, 7, 11, 13 and 18% lower risk of CHD, respectively. Thereby, each additional 6 months associated with 4% lower CHD risk (P trend <0.001).
- This association was similar for stroke, where each additional 6 months associated with an HR or 0.97 (95% CI 0.96-0.98).
- Analyses with total duration of breastfeeding of all children per mother or analyses restricted to women with only 1 child revealed similar results.
Conclusion
In this large Chinese cohort, parous women who had ever breastfed had approximately a 10% lower risk of major CVD subtypes compared with parous women who had never breastfed. Among those who had ever breastfed, there was an inverse loglinear association between the duration of breastfeeding per child and the risk of several major CVDs, except hemorrhagic stroke. If causal, these findings suggest that interventions to increase the likelihood and duration of breastfeeding could have persistent benefits to maternal cardiovascular health.