Infant feeding method and obesity: body mass index and dual-energy X-ray absorptiometry measurements at 9-10 y of age from the Avon Longitudinal Study of Parents and Children (ALSPAC).
BACKGROUND
Previous studies reported inconsistent associations between breastfeeding and body mass index (BMI; in kg/m2). Associations with body fatness are unknown.


OBJECTIVE
We investigated the association of breastfeeding with fatness measured by dual-energy X-ray absorptiometry.


METHODS
The prospective cohort study involved 4325 singletons with measurements at 9-10 y of age to assess the main outcomes of BMI and total and trunk fat masses.


RESULTS
Prevalence of any breastfeeding was 82%. In crude analyses, breastfeeding was inversely associated with total fat mass [% change per category increase (4 categories)] in breastfeeding duration (-4.4%; 95% CI: -3.1%, -5.6%) and trunk fat mass (-0.5%; 95% CI: -1.1%, 0.1%); the odds of adiposity were measured by total [odds ratio (OR): 0.81; 95% CI: 0.75, 0.88] and trunk (OR: 0.78; 95% CI: 0.71, 0.84) fat masses in the top decile. In adjusted models, the inverse association of breastfeeding with mean total fat mass was attenuated by 59% (% change per category increase in breastfeeding duration: -1.8%; 95% CI: -0.5%, -3.1%), but associations with trunk fat mass (% change per category increase in breastfeeding duration: -0.6%; 95% CI: 0.0%, -1.3%) and the ORs for total (0.76; 95% CI: 0.69, 0.84) and trunk (0.74; 95% CI: 0.67, 0.81) fat masses in the top decile were little altered. Children breastfed >or=6 mo had the lowest odds of total fat mass in the top decile (OR: 0.45; 95% CI: 0.33, 0.62). In multivariate models, there was little evidence that breastfeeding was associated with mean or threshold values of BMI.


CONCLUSIONS
The protective association of breastfeeding with mean total fat mass was attenuated somewhat after adjustment for confounders, which indicated that confounding may explain this association. Breastfeeding may protect against obesity if maintained for >or=6 mo.
Toschke
André M
AM
Division of Health and Social Care Research, King's College London, United Kingdom. michael.toschke@kcl.ac.uk
Martin
Richard M
RM
von Kries
Rüdiger
R
Wells
Jonathan
J
Smith
George Davey
GD
Ness
Andrew R
AR
D015502:Absorptiometry, Photon; D050154:Adiposity; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D001942:Breast Feeding; D002648:Child; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000175:diagnosis / Q000517:prevention & control*; D050177:Overweight / Q000502:physiology; D012044:Regression Analysis