Association of breastfeeding duration with carotid intima-media thickness in later life: a systematic review and meta-analysis

Objective: To assess the relationship of breastfeeding duration with maternal ultrasound carotid intima-media thickness (CIMT) in later life. Methods: PubMed, Scopus, Web of Science, Embase, and Cochrane Central database searching up to December 15, 2020, for eligible studies that reported on the breastfeeding duration and ultrasound measurement of CIMT in later life. The exposed group corresponded to breastfeeding duration ≥ 6 months whereas the control group was women with breastfeeding of shorter duration or nil breastfeeding. The methodological quality of reviewed articles was appraised using the Newcastle-Ottawa Scale (NOS). Results are reported as the mean difference (MD) or the standardized MD (SMD) and their 95% confidence intervals (CIs). The study was registered in the PROSPERO database. Results: Of 532 unique studies, three studies met inclusion criteria including 1721 women with a mean age ranging between 36.6 ± 6.9 and 55.7 ± 5.3 years, comparing breastfeeding duration ≥ 6 months versus 1–5 months (NOS: 7–8). Common CIMT was lower in women who breastfed for a longer duration (SMD = −0.10, 95% CI −0.20 to −0.00). Circulating HDL-cholesterol was higher in women with longer breastfeeding duration (MD = 3.25, 95% CI 0.88–5.61). There were no significant differences for total cholesterol, LDL-cholesterol, triglycerides, glucose, and blood pressure between breastfeeding 6 or more months and the control group. Conclusions: The available studies showed lower CIMT and higher HDL-cholesterol levels in women who breastfed for 6 or more months as compared to controls.