Subclinical Inflammation and Duration of Breastfeeding
by Anne Eglash MD, IBCLC, FABM
Longer durations of breastfeeding are associated with a reduced risk of maternal cardiovascular conditions, including heart disease and stroke. This week’s study investigated the mechanisms underlying breastfeeding’s impact on postpartum cardiovascular health in mothers.
The prospective observational cohort study followed 328 women recruited during pregnancy, tracking various cardiometabolic measures over five years postpartum. Participants were categorized into three groups based on exclusive breastfeeding duration: less than 3 months (107 women), 3-6 months (101 women), and 6 months or more (120 women). Demographic information, including age, ethnicity, family history of diabetes, and parity, was collected, alongside measurements of BMI, waist circumference, blood pressure, lipids, glucose, adiponectin, and C-reactive protein (CRP) at 1, 3, and 5 years postpartum.
After controlling for confounding factors, the study found that women who exclusively breastfed for less than 3 months had significantly higher levels of C-reactive protein compared to those who exclusively breastfed for 3 months or longer. Elevated CRP is a marker of subclinical inflammation and is associated with an increased risk of vascular conditions such as hypertension, heart disease, and stroke.
What else? See the question!
- The mothers who exclusively breastfed for less than 3 months had a higher risk of metabolic syndrome at 5 years postpartum.
- The mothers who exclusively breastfed for less than 3 months had higher blood pressures at 5 years postpartum.
- The mothers who exclusively breastfed for less than 3 months had higher cholesterol at 5 years postpartum.
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Abstract
Context
Lactation is associated with lower future risk of cardiovascular disease (CVD) in women but the mechanism(s) underlying this relationship remain unclear.
Objective
We sought to characterize the relationship between duration of exclusive breastfeeding and CV risk factors over the first 5 years postpartum.
Methods
In this prospective cohort study, 328 women underwent serial cardiometabolic characterization (anthropometry, blood pressure [BP], lipids, fasting glucose, adiponectin, C-reactive protein [CRP]) at 1 year, 3 years, and 5 years post partum. Outcomes were CV risk factors in 3 groups defined by duration of exclusive breastfeeding: less than 3 months (n = 107), 3 to 6 months (n = 101), and 6 months or more (n = 120).
Results
The prevalence of metabolic syndrome did not differ between the groups at 3 years but, by 5 years postpartum, was higher in women who had exclusively breastfed for less than 3 months than in those who did so for 3 to 6 and 6 months or more, respectively (14.0% vs 6.9% vs 4.2%; P = .02). However, after adjustment for covariates (including body mass index [BMI]), there were no statistically significant differences between groups in BP, glucose, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, or adiponectin. Indeed, the only CV risk factor difference that persisted after covariate adjustment was that women who had exclusively breastfed for less than 3 months had higher CRP both at 3 years (P = .04) and 5 years (P = .01). Moreover, generalized estimating equation analyses with adjustment for covariates (including time-dependent BMI) showed that CRP remained higher over time in these women, as compared to their peers, from 1 year to 3 years to 5 years post partum (P = .03).
Conclusion
Sustained reduction of subclinical inflammation may contribute to the cardioprotective effect of lactation in women.
This study found that the prevalence of metabolic syndrome was 14% among individuals who exclusively breastfed for less than 3 months, 6.9% for those who breastfed for 3-6 months, and 4.2% for those who breastfed for 6 months or longer.
Metabolic syndrome was defined by criteria including central obesity (high waist-to-hip ratio), elevated blood pressure, low HDL cholesterol, elevated triglycerides, and elevated fasting blood sugar. While the study observed trends of lower blood pressure, higher HDL cholesterol, and lower triglycerides with longer durations of exclusive breastfeeding, these differences did not reach statistical significance, potentially due to the sample size.
Nevertheless, identifying a physiological marker associated with improved cardiovascular outcomes reinforces the clinical benefits of extended exclusive breastfeeding.