Environmental Factors Associated With Childhood-Onset Type 1 Diabetes Mellitus: An Exploration of the Hygiene and Overload Hypotheses | Pediatrics | JAMA Pediatrics | JAMA Network
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August 2010

Environmental Factors Associated With Childhood-Onset Type 1 Diabetes Mellitus: An Exploration of the Hygiene and Overload Hypotheses

Author Affiliations

Author Affiliations: Washington State Department of Health, Communicable Disease Epidemiology, Shoreline (Dr D’Angeli), and Department of Epidemiology (Drs Valbuena and Mueller) and UW Medicine/Harborview Stroke Center, Department of Neurology (Dr Tirschwell), University of Washington, and Division of Emergency Medicine, Department of Pediatrics, Seattle Children's Hospital (Dr Paris), Seattle; and Department of Family Medicine, Tel Aviv University, Ramat Aviv, and Department of Family Medicine, Leumit Health Fund, Tel Aviv, (Dr Merzon), Israel.

Arch Pediatr Adolesc Med. 2010;164(8):732-738. doi:10.1001/archpediatrics.2010.115

Objective  To assess the relationship between selected maternal and infant characteristics and risk of type 1 diabetes mellitus, specifically characteristics identified from birth records that may pertain to the hygiene or overload hypotheses.

Design  Population-based case-control study.

Setting  Washington State from 1987 to 2005.

Participants  All children younger than 19 years hospitalized for type 1 diabetes (International Classification of Diseases, Ninth Revision codes 250.x1 and 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.

Main Exposures  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 cesarean delivery. Infant factors included birth weight, 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.

Results  Consistent with the hygiene hypothesis, type 1 diabetes was negatively associated with having older siblings (for ≥3 siblings, odds ratio [OR], 0.56; 95% confidence interval [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 body mass index of 30 or higher (OR, 1.29; 95% CI, 1.01-1.64) was associated with increased risk of diabetes.

Conclusion  Environmental factors related to decreased antigenic stimulation in early life and maternal obesity may be associated with type 1 diabetes.