1. Exclusive breastfeeding in the first 3 months of life, as opposed to mixed breast and bottle feeding and exclusive bottle feeding, was associated with lower low-density lipoprotein (LDL) cholesterol and lower total cholesterol in adolescence.
2. There was no association between exclusive breastfeeding and body mass index (BMI) or total body fat percentage.
Evidence Rating Level: 2 (Good)
Study Rundown: Previous studies have demonstrated a possible link between breastfeeding in infancy and improved lipid profiles later in life. However, many of these studies have been burdened by bias, specifically related to breastfeeding as associated with higher socioeconomic class in Western culture. In this study, researchers utilized data from a Hong Kong–based cohort study originally designed to investigate the impact of second-hand smoke. Investigators analyzed breastfeeding practices at various ages in the first year of life, comparing those who exclusively breastfed to those who both breast and bottle fed and those who exclusively bottle fed. Researchers completed chart reviews and in-person assessments of weight, body fat percentage, and lipid levels. Though researchers demonstrated a statistically significant association between breastfeeding exclusively for the first 3 months of life and lower LDL and total cholesterol in adolescence, they found no association between breast versus bottle or mixed feeding and BMI or fat percentage. The study has many strengths, including garnering a broad cross-section of the population and evaluating a cultural group in which breastfeeding is not exclusive to those in more advantaged socioeconomic classes. The results, however, ultimately lack clinical significance, as the actual difference between the total LDL and cholesterol levels varied only slightly. Such minor differences are unlikely to have significant impact on long term cardiovascular health.
In-Depth [retrospective cohort]: In this study, researchers utilized data the Hong Kong Children of 1997 birth cohort, which surveyed parents at their first postnatal visit and followed patients through 2012. The initial cohort included 88% of births from April 1, 1997 to May 31, 1997. Researchers queried participants about breastfeeding practices when children were 3, 9, and 18 months, categorizing participants into “exclusive breastfeeding,” “mixed feeding” (both breast and bottle), and “exclusive bottle feeding.” Researchers used record review to passively follow-up weight and height from ages 0 to 5 years, blood pressure, and physiologic well-being. Follow-up lipid panels, body weight, and fat percentages were collected from 2013-2016. Of the 8298 in the original cohort, 3261 were able to provide fasting blood samples and thus were included in the analysis. The mean age at follow up was 17.4 years +/- 0.5 years; few participants had elevated LDL at this age (<1% with greater than or equal to 159 mg/dL). Multilinear regression was used to assess for an association between breast versus bottle feeding and lipid levels. A graded relationship was observed between exclusive breastfeeding in the first 3 months of life and lower total cholesterol (adjusted difference -5.5, 95%CI: -9.5 to -1.4; p = .01, as well as lower LDL (adjusted difference -4.5, 95%CI: -8.1 to -0.8; p = .05. There was no association between breastfeeding practices and BMI or body fat percentage.
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