Objectives: Osteoporosis is a complication of coeliac disease. A gluten-free diet improves but does not normalize bone mineral density in adult patients. Only limited data are available regarding the influence of the disease and diet on bone mineralization in children. The aim of this study was to evaluate the radial bone mineral content and density in children and adolescents who are asymptomatic on a gluten-free diet.
Subjects and methods: The bone mineral content (BMC) and density (BMD) values of the non-dominant radius midshaft in 91 children (53 girls, 38 boys, mean age 11.7 years, mean duration of disease 8.7 years) were determined by single-photon absorptiometry. At the diagnosis and at least three years after commencement of a gluten-free diet, serum calcium, phosphorus, albumin concentrations and alkaline phosphatase activities were measured in all patients, and intact parathormone concentrations in 16 patients.
Results: The mean BMC Z-score value in the female adolescent group only was significantly lower than normal (mean Z-score -1.04, P < 0.01). In contrast, the mean BMD Z-score was significantly higher compared to a healthy population both in girls (mean Z-score +1.36, P < 0.001) and in boys (mean Z-score +0.53, P < 0.02), as well as in the total patient group (mean Z-score +1.01, P < 0.001). The radial diameter was significantly smaller than normal in both pre-pubertal and adolescent groups. Serum laboratory parameters of asymptomatic patients were in the normal range. The parathormone mean value was significantly lower after at least three years of gluten-free diet than at diagnosis (mean +/- SD 3.77 +/- 1.07 versus 7.89 +/- 2.54 pmol/l, P < 0.01), but significantly higher compared to controls (2.89 +/- 0.90 pmol/l, P < 0.05).
Conclusions: These data indicate that treated, asymptomatic coeliac children and adolescents have normal or even higher radius mineral density values than controls, but the bone size remains reduced. Although there is no direct evidence of calcium malabsorption in this cohort of coeliac patients, the slightly higher parathormone levels, together with some other factors, particularly delayed puberty, may result in reduced bone size.