(1102) Breastfeeding Intensity and Long-Term Dyslipidemia Risk in Women with Prior Gestational Diabetes: A Mediation Analysis

Women with prior gestational diabetes (GDM) face elevated risks of long-term dyslipidemia. While breastfeeding is generally beneficial for postpartum metabolic health, its long-term effects on lipid profiles in this population remain unclear. We previously showed that higher breastfeeding intensity was associated with improved lipid profiles in early postpartum. This study examined whether high-intensity breastfeeding (HIB) in early postpartum is associated with reduced risk of elevated triglyceride-to-HDL (TG/HDL) ratio ( >=2.1) at 5 years, and whether early postpartum TG/HDL ratio mediates this association.


Study Design:

We analyzed data from 521 women with prior GDM followed for 5 years at a Japanese tertiary perinatal center. Breastfeeding intensity was classified as HIB or non-HIB during early postpartum. TG/HDL ratio was assessed at early postpartum and again at 5 years. The primary outcome was TG/HDL >=2.1 at 5 years. Mediation analysis was performed using bootstrapping (n=1000), adjusting for age, prepregnancy BMI, postpartum week, maternal weight, and fasting glucose at 5 years.


Results:

HIB was significantly associated with lower early postpartum TG/HDL ratio (β = –0.16), which strongly predicted TG/HDL >=2.1 at 5 years (β = –0.99) (Figure). The indirect effect of HIB on 5-year dyslipidemia risk through early TG/HDL ratio was significant (bootstrapped 95% CI: –0.241 to –0.096). The direct effect was small and marginally positive (β = +0.11). These findings suggest that HIB indirectly reduces long-term dyslipidemia risk by improving early TG/HDL ratio.


Conclusion:

Among women with prior GDM, early high-intensity breastfeeding did not directly lower 5-year dyslipidemia risk but had a significant indirect effect via early lipid improvement. Promoting breastfeeding may serve as a metabolic window for long-term cardiovascular risk reduction.