Duration of breastfeeding and risk of overweight in childhood: a prospective birth cohort study from Germany

Background: Whereas a recently published meta-analysis showed that ever breastfeeding reduces the risk of obesity inchildhood significantly, the recent literature describing the relationship between duration of breastfeeding and risk of overweight or obesity in childhood remains inconclusive. Methods: Between November 2000 and November 2001, all mothers and their newborns were recruited after delivery at the Department of Gynecology and Obstetrics at the University of Ulm, Germany. Active follow-up was performed at the age of 12 months and 24 months. Results: Of the 1066 children included in the baseline examination, information on body mass index was available for 855 (80%) at the 2-year follow-up. At this age 72 children (8.4%) were overweight and 24 (2.8%) were severely overweight. Whereas 76 children (8.9%) were never breastfed, 533 children (62.3%) were breastfed for at least 6 months, and 322 children (37.7%) were exclusively breastfed for at least 6 months. Compared to children who were breastfed for less than 3 months, the adjusted odds ratio (OR) for overweight was 0.4 (95% confidence interval (CI) 0.2-0.8) in children who were breastfed for at least 6 months. When considering the time of exclusive breastfeeding, the adjusted OR for overweight was 0.8 ( 95% CI 0.4; 1.5) in children who were exclusively breastfed for at least 3 but less than 6 months and 0.4 (95% CI 0.2; 0.9) in children who were exclusively breastfed for at least 6 months compared to children who were exclusively breastfed less than 3 months. Conclusion: These results highlight the importance of prolonged breastfeeding for the prevention of overweight in children.