To assess the impact of disease activity on acquired peak bone mass and bone turnover in young adult patients with either persistent juvenile arthritis (JA) or a history of JA (JA in remission).
Two hundred twenty-nine patients with JA were studied after a mean +/- SD of 15.6 +/- 2.4 years in women and 14.9 +/- 2.1 years in men since disease onset. One hundred forty-five women and 84 men were over the age of 20 at the time of examination (mean +/- SD age 24.9 +/- 2.9 years for women and 25.2 +/- 3.1 years for men). Forty-one healthy women (mean +/- SD age 27.4 +/- 3.1 years) and 55 healthy men (mean +/- SD age 25.7 +/- 3.1 years) served as a reference group. Bone mineral density (BMD) was analyzed by dual x-ray absorptiometry. Serum osteocalcin concentrations and urinary concentrations of deoxypyridium (D-Pyd) were measured. Linear regression analyses were performed to evaluate the impact of disease on BMD.
Patients with persistent disease had significantly lower BMD compared with healthy subjects (P < 0.001 for women at all measured sites and for men at the femoral neck and total body; P < 0.05 for men at the radius and lumbar spine). Of the patients with a history of JA, only women had significantly lower BMD at the femoral neck and total body (P < 0.05). Patients with persistent JA had significantly more osteopenia and osteoporosis than healthy subjects, while patients with a history of JA had more frequent osteopenia only in the total body. Weight, urinary concentration of D-Pyd, and belonging to the patient group significantly affected BMD at all measured sites in the entire study population, while analysis of all patients found that only the number of months taking corticosteroids significantly affected BMD at all measured sites. However, the impact of the variables differed from site to site.
Our findings imply that most young adults with JA attain the same BMD as healthy subjects if the disease goes into remission, while young adults with active disease have increased risk for osteopenia and osteoporosis.