BACKGROUND: Previous reports have found associations between having been breast-fed and a reduced risk of being overweight. These associations may be confounded by sociocultural determinants of both breast-feeding and obesity. We addressed this possibility by assessing the association of breast-feeding duration with adolescent obesity within sibling sets. METHODS: We surveyed 5,614 siblings age 9 to 14 years and their mothers. These children were a subset of participants in the Growing Up Today Study, in which we had previously reported an inverse association of breast-feeding duration with overweight. We compared the prevalence of overweight (body mass index exceeding the age-sex-specific 85th percentile) in siblings who were breast-fed longer than the mean duration of their sibship with those who were breast-fed for a shorter period. Then we compared odds ratios from this within-family analysis with odds ratios from an overall (ie, not within-family) analysis. RESULTS: Mean +/- standard deviation breast-feeding duration was 6.4 +/- 4.0 months, and crude prevalence of overweight was 19%. On average, siblings who were breast-fed longer than their family mean had breast-feeding duration 3.7 months longer than their shorter-duration siblings. The adjusted odds ratio (OR) for overweight among siblings with longer breast-feeding duration, compared with shorter duration, was 0.92 (95% confidence interval = 0.76-1.11). In overall analyses, the adjusted OR was 0.94 (0.88-1.00) for each 3.7-month increment in breast-feeding duration. CONCLUSION: The estimated OR for the within-family analysis was close to the overall estimate, suggesting that the apparent protective effect of breast-feeding on later obesity was not highly confounded by unmeasured sociocultural factors. A larger study of siblings, however, would be needed to confirm this conclusion.
BACKGROUND: Previous reports have found associations between having been breast-fed and a reduced risk of being overweight. These associations may be confounded by sociocultural determinants of both breast-feeding and obesity. We addressed this possibility by assessing the association of breast-feeding duration with adolescent obesity within sibling sets. METHODS: We surveyed 5,614 siblings age 9 to 14 years and their mothers. These children were a subset of participants in the Growing Up Today Study, in which we had previously reported an inverse association of breast-feeding duration with overweight. We compared the prevalence of overweight (body mass index exceeding the age-sex-specific 85th percentile) in siblings who were breast-fed longer than the mean duration of their sibship with those who were breast-fed for a shorter period. Then we compared odds ratios from this within-family analysis with odds ratios from an overall (ie, not within-family) analysis. RESULTS: Mean +/- standard deviation breast-feeding duration was 6.4 +/- 4.0 months, and crude prevalence of overweight was 19%. On average, siblings who were breast-fed longer than their family mean had breast-feeding duration 3.7 months longer than their shorter-duration siblings. The adjusted odds ratio (OR) for overweight among siblings with longer breast-feeding duration, compared with shorter duration, was 0.92 (95% confidence interval = 0.76-1.11). In overall analyses, the adjusted OR was 0.94 (0.88-1.00) for each 3.7-month increment in breast-feeding duration. CONCLUSION: The estimated OR for the within-family analysis was close to the overall estimate, suggesting that the apparent protective effect of breast-feeding on later obesity was not highly confounded by unmeasured sociocultural factors. A larger study of siblings, however, would be needed to confirm this conclusion.
Authors: M W Gillman; S L Rifas-Shiman; C A Camargo; C S Berkey; A L Frazier; H R Rockett; A E Field; G A Colditz Journal: JAMA Date: 2001-05-16 Impact factor: 56.272
Authors: S L Rifas-Shiman; M W Gillman; A E Field; A L Frazier; C S Berkey; C A Tomeo; G A Colditz Journal: Am J Prev Med Date: 2001-05 Impact factor: 5.043
Authors: Michael S Kramer; Tong Guo; Robert W Platt; Stanley Shapiro; Jean-Paul Collet; Beverley Chalmers; Ellen Hodnett; Zinaida Sevkovskaya; Irina Dzikovich; Irina Vanilovich Journal: Pediatrics Date: 2002-08 Impact factor: 7.124
Authors: Richard M Martin; Rita Patel; Michael S Kramer; Lauren Guthrie; Konstantin Vilchuck; Natalia Bogdanovich; Natalia Sergeichick; Nina Gusina; Ying Foo; Tom Palmer; Sheryl L Rifas-Shiman; Matthew W Gillman; George Davey Smith; Emily Oken Journal: JAMA Date: 2013-03-13 Impact factor: 56.272
Authors: Molly M Lamb; Dana Dabelea; Xiang Yin; Lorraine G Ogden; Georgeanna J Klingensmith; Marian Rewers; Jill M Norris Journal: Ann Nutr Metab Date: 2009-11-27 Impact factor: 3.374