To assess the relationship between selected maternal and infant characteristics and risk of Type 1 diabetes, specifically characteristics identified from birth records that may pertain to the “Hygiene” or “Overload” hypotheses.
Population-based case-control study.
Washington State from 1987–2005.
All children <19 years hospitalized for Type 1 diabetes (ICD-9 250.x1, 250.x3) identified (N=1852) from hospital discharge data and linked with their birth certificates. Controls (N=7408) were randomly selected from birth records, frequency matched on year of birth.
Maternal factors included age, race, educational attainment, marital status, use of Medicaid insurance, body mass index, prepregnancy weight, prior births, timing and adequacy of prenatal care, and caesarian delivery. Infant factors included birthweight, size for gestational age, and gestational age.
Main Outcome Measure
The main outcome was first hospitalization for Type 1 diabetes mellitus; adjusted odds ratios were estimated for the association of selected maternal and infant characteristics with Type 1 diabetes.
Consistent with the hygiene hypothesis, Type 1 diabetes was negatively associated with having older siblings (for 3+ siblings, OR=0.56, 95% CI 0.45–0.70), and with indicators of lower economic status or care access, such as an unmarried mother (OR=0.79, 95% CI 0.69–0.91), inadequate prenatal care (OR=0.53, 95% CI 0.40,–0.71), or Medicaid insurance (OR=0.67, 95% CI 0.58–0.77). Related to the overload hypothesis, maternal BMI >30 (OR=1.29, 95% CI 1.01–1.64) was associated with increased risk of diabetes.
Environmental factors related to decreased antigenic stimulation in early life and maternal obesity may be associated with Type 1 diabetes.