Among children whose introduction to bottle-feeding is delayed, the longer duration of breastfeeding may confer protection against obesity at age 6 years, according to a study published in Childhood Obesity.
“Differences in hormone and protein content between breast milk and formula may play a role in increasing risk of excess weight and obesity,” Juan Antonio Ortega-Garcia, MD, PhD, of the pediatric environmental health specialty unit at the Virgen de la Arrixaca University Hospital, University of Murcia, Spain, and colleagues wrote in the study background. “Also, recommendations have been made to study mode of administration and its impact on childhood obesity to determine its role in appetite regulation, regardless of substance consumed.”
Ortega-Garcia and colleagues analyzed breastfeeding data and anthropometric measurements in 324 mother-child pairs participating in MALAMA, an ongoing, longitudinal, prospective birth-cohort study. Interviews were conducted at neonatal discharge and by phone at 1, 3, 6 and 12 months. Researchers assessed anthropometric data from well-child exams at ages 1, 2, 4 and 6 years. WHO definitions were used to determine breastfeeding status, defined as “exclusive” (only breast milk), “full” (exclusive breastfeeding or almost exclusive) or “any” breastfeeding and BMI. The researchers used multiple log-linear and ordinal regression analyses to assess the effects of breastfeeding in subsequent obesity and overweight, while factoring in possible confounders.
The median duration of full breastfeeding was 63.5 days, and 21% of children were fully breastfed for at least 6 months. At 12 months, the prevalence of any breastfeeding was 19.2%.
At age 6 years, 32.8% of children had overweight, and 17.7% of children had obesity, according to researchers.
Excess weight at age 6 years was more prevalent in children with the following factors: high weight gain in the first year of life, maternal high BMI, maternal smoking or alcohol consumption during pregnancy, and low parental education attainment.
Univariate analysis showed a reduced likelihood of obesity or overweight among children who were exclusively breastfed or fully breastfed.
Log-linear regression revealed the following variables as predictive of excess weight at 6 years: pregestational maternal log BMI (R2 = 0.127; P < .01), weeks breastfed (R2 = –.035; P < .01), infant weight gain (R2 = 0.348; P < .01) and maternal alcohol consumption during pregnancy (R2 = 0.266; P < .01).
A multivariate ordinal logistic analysis revealed an association between full breastfeeding and BMI decrease (R2 = –0.052; P = .04). Researchers also observed an association between maternal BMI (R2 = 0.093; P < .01) and weight gain (R2 = 0.407; P = .01) in the first year of life with an increase in overweight/obesity.
There was no statistically significant association between family income or parental education and overweight/obesity at age 6 years, but researchers noted an inverse relationship between level of income at birth and average BMI at age 6 years.
“In our study, we established a dose-dependent relationship between [full breastfeeding] duration and weight status in early childhood,” the researchers wrote. “The use of standardized measures, particularly of breastfeeding, will go a long way in better understanding this protective effect internationally.” – by Jennifer Byrne
Disclosures: The authors report no relevant financial disclosures.