Is the association of breastfeeding with child obesity explained by infant weight change?
OBJECTIVE
Breastfeeding and infant weight change are both associated with adiposity. We examined the extent to which infant weight change mediates the association between breastfeeding and adiposity at age 3 years.


METHODS
We studied 884 children in a prospective cohort study. We determined breastfeeding status in the first 6 months. Our primary outcomes at 3 years were body mass index (BMI) z score and the sum of subscapular and triceps skinfold thicknesses (SS + TR); we also assessed obesity. We defined infant weight change as change in weight-for-age z score between birth and 6 months. We performed multivariable regression analyses.


RESULTS
At age 6 months, 25.0% of infants were fully breastfed. At age 3 years, mean (standard deviation) BMI z score was 0.45 (1.03). In linear regression analyses adjusted for mother's educational level, race/ethnicity, smoking, BMI, pregnancy weight gain and birth weight (adjusted for gestational age), the BMI z score of fully breastfed children was 0.17 (95% CI: -0.43, 0.09) units lower than never breastfed children. After additional adjustment for infant weight change, the estimate was attenuated (-0.03, 95% CI: -0.27, 0.20). Adjustment for infant weight change only modestly attenuated estimates for SS + TR (from -1.48 mm [95% CI: -2.52, -0.44] to -1.16 mm [95% CI: -2.18, -0.14]), and for the odds of being obese (from 0.21 [95% CI: 0.07, 0.68] to 0.29 [95% CI: 0.08, 1.05]).


CONCLUSIONS
Infant weight change between birth and 6 months mediates associations of breastfeeding with BMI, but only partially with indicators of child adiposity.
van Rossem
Lenie
L
The Generation R Study Group, Erasmus MC-University Medical Centre Rotterdam, Rotterdam, the Netherlands. l.vanrossem@erasmusmc.nl
Taveras
Elsie M
EM
Gillman
Matthew W
MW
Kleinman
Ken P
KP
Rifas-Shiman
Sheryl L
SL
Raat
Hein
H
Oken
Emily
E
D050154:Adiposity; D000328:Adult; D000367:Age Factors; D001724:Birth Weight; D015992:Body Mass Index; D001942:Breast Feeding; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008404:Massachusetts; D009765:Obesity / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D016017:Odds Ratio; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012885:Skinfold Thickness; D015430:Weight Gain