Bone mineral content in young adults with active or inactive juvenile idiopathic arthritis and in controls

To obtain information on bone mineral content (BMC) in juvenile idiopathic arthritis (JIA) in young adulthood.

BMC measurements of 116 young adults with JIA and controls were performed at the lumbar spine and the proximal femur by dual-energy X-ray absorptiometry (DXA).

Patients were divided into the JIA-active group (n = 73) and the JIA-inactive group (n = 43). Fifty-five per cent of men and 30% of women had their disease in remission. Forty-eight per cent in the JIA-active group and 16% in the JIA-inactive group had used glucocorticoids (p < 0.001). Mean BMC in the femoral neck was 5.76 (SD 0.21) g for men and 4.74 (SD 0.10) g for women in the JIA-active group; 5.84 (SD 0.23) g for men and 4.59 (SD 0.06) g for women in the JIA-inactive group; and 6.65 (SD 0.20) g for men and 4.78 (SD 0.07) g for women in the controls. Both JIA groups had lower BMC values in the femoral neck than the controls (p < 0.001), but a statistically significant difference was found among men (p = 0.006). There was no significant difference in mean BMC in the lumbar spine between the JIA groups and the controls, nor between men and women. Glucocorticoid use, weight and also height among women were associated statistically significantly with BMC in the femoral neck.

Young adults, especially men, with JIA have reduced BMC values in the femoral neck. Glucocorticoid use and weight, but not disease activity, seem to be associated with lower BMC. However, osteoporosis is rare.