Diabetes Care, Vol 15, Issue 5 626-631, Copyright © 1992 by American Diabetes Association
Early infant diet and risk of IDDM in blacks and whites. A matched case-control study
JN Kostraba, JS Dorman, RE LaPorte, FW Scott, AR Steenkiste, M Gloninger and AL Drash
Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, PA 15261.
OBJECTIVE--To investigate the role of early infant feeding in the
development of insulin-dependent diabetes mellitus (IDDM) and to determine
whether an association exists in both blacks and whites. RESEARCH DESIGN
AND METHODS--Black and white diabetic subjects were recruited from the
Allegheny County and Children's Hospital of Pittsburgh IDDM Registries.
Extensive infant diet histories were obtained from the diabetic subjects
and their nondiabetic siblings, who were used as nondiabetic control
subjects. Each diabetic subject was matched outside his/her family to an
unrelated nondiabetic control subject on birth order, birth year (+/- 2
yr), and race, which resulted in 211 case-control pairs with a mean birth
year of 1967. RESULTS--In whites, diabetic subjects were less likely to
have been breast-fed than control subjects (odds ratio [OR] 0.5, 95%
confidence interval [CI] 0.3, 0.9). Breast-feeding prevalence did not
differ between black diabetic subjects and control subjects. Duration of
overall and exclusive breast-feeding did not differ between diabetic and
control subjects in the black and white cohorts. The following analyses,
which examined whether the timing of the first breast milk substitute to
which the infant was exposed differed between diabetic and control
subjects, were conducted for exposure to any breast milk substitute and to
breast milk substitutes that were cow's milk based. In whites, age at
exposure to any breast milk substitutes and cow's milk-based substitutes
were similar between diabetic and control subjects. In blacks, the first
exposure to breast milk substitutes occurred significantly earlier for any
substitute (5.1 vs. 11.9 wk, P = 0.02) and marginally earlier for cow's
milk-based substitutes (3.9 vs. 8.5 wk, P = 0.07) in diabetic subjects
compared with control subjects. The first exposure to breast milk
substitutes was more likely to occur by 3 mo of age in black diabetic
subjects compared with black control subjects (OR 3.3, 95% CI 1.1-10.0)
after adjusting for maternal age at birth. The addition of breast-feeding
status to the model only slightly weakened this association in blacks.
CONCLUSIONS--The analyses of this study cohort suggest that the observed
protective effect of breast-feeding on the risk of IDDM may be related to
differences in the age at exposure to breast milk substitutes in blacks but
not in whites.