Association of breastfeeding duration with cardiac structure and function in 4 years old.

Background: Breast milk is an important source of nutrition for infant development. But few studies have investigated the relationship between breastfeeding duration and children's cardiac structure and function.

Objectives: To assess the association of the duration of breastfeeding in infancy with cardiac structures and functions in 4-year-old children.

Methods: The study analyzed data from 891 mother-offspring pairs in the Shanghai Birth Cohort (SBC) with complete 4-year follow-up and breastfeeding questionnaires. It excluded children with congenital heart defects or missing echocardiography data at age 4. Breastfeeding duration, including exclusive and mixed feeding, was categorized into three groups (<6months, 6-12months, >12months) based on questionnaires at 3 days, 24 days, 6, 12, and 24 months. Echocardiographic data were measured following 2010 American Society of Echocardiography recommendations.

Results: The results showed that: compared to 4-year-old children who were breastfed for less than 6 months, those breastfed for more than 6 months had bigger left atrial and ventricular volume, including increased left atrial diastolic volume [LAVd (β: 2.09, 95% CI: 1.35, 2.83)], left atrial systolic volume [LAVs (β: 0.92, 95% CI: 0.53, 1.3)], left ventricular diastolic volume [LVEDV (β: 2.00, 95% CI: 0.36, 3.62)] and systolic volume [LVESV (β: 0.87, 95% CI: 0.17, 1.57)]. Children breastfed over 12 months showed similar cardiac structural changes as those breastfed 6-12 months. These findings were more pronounced in girls and low birthweight children.

Conclusions: Four-year-old children who were breastfed for six months or more had increased left heart volume, and this association was influenced by gender and birthweight.