Hospitalized prenatal and childhood infections and obesity in Danish male conscripts.

Purpose: We examined the relation between early life infections and adult obesity.

Methods: A cohort of Danish males who underwent mandatory army fitness examinations was studied. Hospitalizations for childhood infections and their mothers' hospitalization for infection during pregnancy were identified via the Danish National Registry of Patients. The outcome was obesity (body mass index ≥ 30 kg/m(2)) at conscription. We calculated prevalence odds ratios (OR) and 95% confidence intervals (CI) associating the obesity with whether the conscript had a hospitalization for infection up to age 5, and separately, whether the conscript's mother was hospitalized for an infection prenatally.

Results: Of the 17,456 men, 13% had a childhood infection (8.2% of whom were obese, compared with 7.4% without childhood infection); 1.2% of conscripts were exposed to a prenatal infection (10% of whom were obese, compared with 7.4% without prenatal infection). For childhood infection, the adjusted OR was 1.21 (95% CI, 1.01-1.44); stratified analyses suggested the association may be greater among conscripts born preterm (adjusted OR, 2.08; 95% CI, 1.06-4.09), whereas among the conscripts who were full term, the adjusted OR was 1.15 (95% CI, 0.96-1.38). For prenatal infection, the adjusted OR was 1.34 (95% CI, 0.82-2.19).

Conclusions: We found a small association between both prenatal and childhood infections and prevalent obesity in early adulthood, although the results may be partly explained by unmeasured confounders.