Bone mineral density reduction in adolescents with systemic erythematosus lupus: association with lack of vitamin D supplementation

The aim of this study is to evaluate body composition and the bone mineral density in female adolescents with juvenile systemic lupus erythematosus. Body composition (BC) and bone mineral density (BMD) were evaluated in an observational cohort study with 35 postmenarcheal adolescent females. The variables studied were as follows: current and cumulative corticosteroid dose, intake of supplements containing calcium and vitamin D, 24-h proteinuria, body mass index (BMI), and height for age (Z-score). BC was assessed using dual-energy X-ray absorptiometry (DXA) at two time points (median interval of 1.2 years). The fat mass index (FMI = fat mass in kilograms divided by the height in meters squared) and lean mass index (LMI = lean mass in kilograms divided by the height in meters squared) were calculated based on the DXA results. BMD was classified according to the International Society of Clinical Densitometry (low BMD for chronological age < −2.0 standard deviations). .The mean age of the subjects was 15.4 ± 1.8 years. Of patients, 54.3 % were normal weight, 22.8 % were overweight, 22.8 % were obese, and 8.6 % had short stature. Low BMD for chronological age was observed in 42.8 % of patients, and 60 % were not taking vitamin D. There was no significant difference between the two time points with respect to FMI, LMI, or body mass index Z-score (ZBMI); however, BMD has decreased significantly (p = 0.011). There was an association between not taking a vitamin D supplement and decreased BMD (p = 0.027). Almost half of the patients had altered nutritional status. The BMD decrease in adolescents with juvenile systemic lupus erythematosus (JSLE) was associated with the lack of vitamin D supplementation, highlighting the importance of well-defined vitamin D supplementation protocols.