Figure 1.

Forest plot of antibiotic use and type 1 diabetes risk in both cohorts.* *Results from the MoBa cohort (n = 84 407) are in the top lines, marked with a square, and results from the register cohort (n = 537 460) are in the bottom line, marked with a diamond. ^†Common reference for all exposure categories in the relevant time period. ^‡Hazard ratios estimated through Cox regression adjusted for child’s sex, maternal age and parity, maternal type 1 diabetes, smoking in pregnancy, education level, pre-pregnancy BMI, prematurity, birthweight, mode of delivery, infections and acetaminophen use during the relevant time period (pregnancy, or first 6 or 18 months of life) in the MoBa cohort. The register cohort was adjusted for the same variables, with the exception of maternal pre-pregnancy BMI, smoking, acetaminophen use and infections. Adjusting for maternal smoking in the register-based cohort did not appreciably change our estimates; we present data not adjusted for maternal smoking, as there was a high proportion with missing data in the register-based cohort. Children with complete data on covariates (n = 67 718 for analysis at 0-18 months of age) were included in adjusted model for the MoBa cohort.