[Developmental osteopenia: decrease of bone mineral density or systemic impairment?]

In the quantitative evaluation of bone osteopenia is defined as a decrease of mineral density by more than 1 SD from the established normal values (age, sex, peak bone mass...). The border of osteopenia and osteoporosis is demarcated by -2.5 SD (T-score) in adults, while in children the most proper is considered to be -2.0 SD (Z-Score). The aim of the study was to determine whether developmental osteopenia is accompanied by biochemical abnormalities and what are clinical symptoms concomitant with this condition. The studies include 28 children aged 5-17 years, in whom no chronic disease, especially of locomotor system, was found. The basis for diagnosis was densitometric examination of bone, with DEXA method (densitometer by Lunar), vertebral column (Spine) in the pediatric program or for adults. The most frequent causes for referring to the examination were pain in the spine, limbs or history of multiple bone fractures. In the performed biochemical examinations hypomagnesemia, decreased concentration of 25OHD and PTH in blood serum, increased activity of bone isoenzyme of alkaline phosphatase as well as increased excretion of hydroxyproline in urine, were found in several children. In about 1/3 of the children low body mass, and in some cases also retardation of the bone age was revealed. The results of our studies allow a conclusion, that in children with certain clinical abnormalities from locomotor system osteopenia may take place. This disturbance is concomitant with various deviations in calcium-phosphate metabolism and requires adequate therapy. It may be supposed, that in the majority of children, osteopenia was caused by low dietary calcium intake, together with reduced physical activity and vitamin D deficiency. The observations and conclusions from the study are of important practical significance, because children with osteopenia are the risk group for the appearance of osteoporosis in their future life.