Maternal weight and hypertension as risk factors for juvenile idiopathic arthritis: a prospective population-based pregnancy cohort study.

By the end of follow-up, all children were ≥14 years old and 85% were ≥16 years old.

Each 1 SD (~6 kg) increase in gestational weight gain was associated with modestly higher odds of juvenile idiopathic arthritis (aOR 1.12, 95% CI 1.00 to 1.26), particularly among women with prepregnancy obesity (aOR 1.40, 95% CI 1.10 to 1.77).

Hypertension did not mediate the GWG-JIA association (p>0.05).

Among children with lower Polygenic Risk Score, maternal obesity was associated with a lower juvenile idiopathic arthritis risk (aOR 0.37, 95% CI 0.17 to 0.80).