Move Together Buckinghamshire: protocol for a pragmatic mixed-methods evaluation of a community physical activity programme for older adults with long-term conditions.

Juvenile idiopathic arthritis (JIA) arises from a complex interplay between genetic susceptibility and environmental exposures, but few environmental risk factors have been consistently identified. Excessive gestational weight gain (GWG) and hypertensive disorders of pregnancy are associated with systemic inflammation during pregnancy and may influence fetal immune development. In other early-onset autoimmune diseases, genetic susceptibility modifies associations with early-life environmental exposures, but whether similar gene–environment interactions contribute to the development of JIA remains largely unexplored.