Fig. 1. Purchased antibiotic courses before index date^a in the matched case–control^b study.

The numbers of tetracycline, clindamycin, fluoroquinolone, and other antibiotics courses were relatively low. ^aIndex date = date of diagnosis for children who developed autoimmune diseases (type 1 diabetes, autoimmune thyroiditis, juvenile idiopathic arthritis, and inflammatory bowel diseases) and respective date for their matching controls. ^bCases = 242 children who developed autoimmune diseases by the end of follow-up (December 31, 2018) at a median age of 16 years. Each child in the case group was matched with one to four children of similar age, sex, residential area, gestational age (preterm/term), and delivery method (cesarean section/vaginal), comprising control group of 708 children.