University of Michigan
Department of Pediatrics
Evidence-Based Pediatrics Web Site

Question

• 6 mo female with weight >>95% presents for well-child examination. Parents ask whether breastfeeding their daughter will decrease her risk of obesity in the future.

Clinical Bottom Lines

1. Breastfeeding (BF) for > 6mos is associated with a 22% decreased incidence of overweight in adolescents.¹
2. Longer duration of BF is associated with decreased rate of becoming overweight.1 The AAP recommends 12 mos of BF.
3. Overweight adolescents (BMI > 95% for age & sex) are at increased risk of becoming obese adults. Nationally, 10.7-12.6% of adolescent males and 8.2-10.4% of adolescent females are overweight.²
4. Maternal obesity (BMI >30) is strongly correlated with increased incidence of overweight in adolescents.¹
5. Timing of introduction of solids, formula, and cow's milk did not affect the data.

Summary of Key Evidence

1. 15,341 adolescents ages 9-14 (children of Nurses' Health Study II) and their parents were mailed and responded to separate questionnaires addressing weight, height, infant feeding practices, diet, activity level, mother's weight & height, Tanner stage, etc.¹
2. Feeding practices divided into length of breastfeeding (0, <1 mo, 1-3 mo, 4-6 mo, 6-9 mo, >9 mo), and type of feeding (breast vs formula).
3. Multivariate analysis was performed with breastmilk versus formula and relationship to adolescent overweight. The results were adjusted for sex, age, tanner stage, mother's BMI, energy intake, physical activity, hours of TV watching, and birth weight.
4. In first six months of life, 62% of the subjects were mostly or only fed breast milk, and 31% were mostly or only fed formula.
5. Odds Ratio (OR) for being overweight as an adolescent if fed only or mostly breast milk for first 6 months was 0.78 (CI 0.66-0.91)
6. If mother's BMI < 25 vs > 30, OR = 0.27 for overweight child regardless of breastfeeding status.

Additional Comments

• A higher percentage of infants were breastfed in this study than nationally. Also, there was a lower percentage of overweight adolescents in this study than nationally.¹
• A homogeneous (mostly Caucasian and all children of RN's) population was included in the study.
• The mechanism or causal relationship between breastfeeding and adolescent obesity is unknown.
• This study gives one more reason to promote breastfeeding, especially to those children with obese parents who are already at higher risk of becoming overweight.

Citation

1. Gillman MW, Rifas-Shiman SL, Camargo CA, Berkey CS, Frazier AL, Rockett HRH, Field AE, Colditz GA. Risk of overweight among adolescents who were breastfed as infants. JAMA 2001; 285: 2461-2467.
2. Toriano RP, Flegal KM. Overweight children and adolescents: description, epidemiology and demographics. Pediatrics 1998; 101: 497-504.

CAT Author: Krista Hodne, MD

CAT Appraisers: Jon Fliegel, MD

Date appraised: August 16, 2001