The association between lean mass and bone mineral content in the high disease activity group of adult patients with juvenile idiopathic arthritis

Abstract

BackgroundThe study is aimed to evaluate body composition and bone status in adolescent and adult patients with active juvenile idiopathic arthritis (JIA) untreated with tumor necrosis factor alpha inhibitors.MethodsAdult patients (12 male and 19 female) with active JIA and 84 healthy age- and gender- matched controls were enrolled into the study. Body composition (tissue mass in grams, lean mass, fat mass and bone mineral content as a fraction of tissue mass) and areal bone mineral density parameters (aBMD) at the lumbar spine, proximal femur, femoral neck, distal radius and total body were assessed using dual energy x-ray absorptiometry (DXA), and correlated with clinical characteristics of the disease and physical performance tests. Disease activity was assessed using high-sensitivity C-reactive protein (hsCRP) and disease activity score 28 (DAS 28). Differences between the groups were tested by t-test, and One-way ANOVA. Correlations were assessed using the Pearson correlation coefficients and multiple linear regression analysis. Significances were counted at the 0.05 level.ResultsIn patients with clinically active JIA (DAS 28, 6.36 ± 0.64, hsCRP, 18.36 ± 16.95 mg/l), aBMD at all measured sites, bone mineral content (BMC) and lean mass were reduced, and fat mass was increased as compared with healthy controls. Significant negative correlations were observed between BMC and disease duration, use of glucocorticoids (GCs), and fat mass, respectively. A positive correlation was found between BMC and lean mass, and between the body fat fraction and the use of GCs. Using multiple linear regression analysis, lean mass was the only significant predictor of BMC of total body both in men and women, and of BMC of legs (only in men). Lean mass was also the only predicting factor of total proximal femur BMD and femoral neck BMD. No significant correlations have been determined among the body composition parameters and DAS 28 or hsCRP endpoints.ConclusionsIn adult patients with long-term active JIA, lean mass was the main determining factor of total body and leg BMC, and total proximal femur and femoral neck aBMD.

Serum sclerostin in high-activity adult patients with juvenile idiopathic arthritis

“…Juvenile idiopathic arthritis (JIA) is a systemic autoimmune inflammatory connective tissue disease with onset occurring before age 16 years. It is associated with a decrease in bone mass, thinning of the cortical bone [ 1 , 2 ], sarcopenia [ 3 , 4 ] and an increased risk of fractures [ 5 ]. Bone loss may be systemic or localized to the periarticular bone due to arthritis of the affected joint.…”

Body composition in long-standing juvenile dermatomyositis: associations with disease activity, muscle strength and cardiometabolic measures

“…While one of the studies showed lower skeletal muscle mass in (female) patients than in controls ( 14), no differences in body fat between patients and controls were found (5,14). For comparison, studies in juvenile onset SLE and JIA have demonstrated lower muscle mass and higher BF% in patients with both early (17,29) and longstanding disease (16,30).…”

Juvenile idiopathic arthritis and physical activity: Possible inflammatory and immune modulation and tracks for interventions in young populations

“…This finding can be explained by the inactive lifestyle of JIA patients [23] due to chronic joint pain [8,24]. The lack of physical activity leads to increased muscle weakness and atrophy that aggravate the altered body composition in JIA patients, where fat mass is increased and bone and lean mass decreased [25,26]. In addition, medications such as glucocorticoids have direct actions on muscle loss and osteoporosis [26].…”