PURPOSE: Assessment of the effect of low-calcium diet on bone mineral content in children and adolescents. MATERIAL AND METHODS: The study involved 89 children (49 girls and 40 boys) aged 5-18 years, in whom diseases affecting bony metabolism had been excluded. Children with a history of dietary calcium content below 500 mg/day were recruited. The study group was divided according to age: group I, age 5-9 years (children before puberty); group II, age 9-15 years (early puberty); group III, 15-18 years (late puberty). Dual energy X-ray absorptiometry (DEXA) was used for densitometric measurements. Bone mineral density (BMD) was assessed in the whole skeleton (total BMD), in vertebrae L2-L4 (spine BMD) in g/cm2 and as Z-score. Concentrations of Ca, Ca2, P, activity of alkaline phosphatase (AP) and its bony isoenzyme were determined in the serum. RESULTS: Total bone mass below 5th percentile (according to the norm for age and gender) was found in 56.98% of the children involved in the study. A significant reduction was noted in the spine mineral mass in boys (p < 0.01) as compared to girls (0.731 +/- 0.17 g/cm2 and 0.835 +/- 0.19 g/cm2, respectively). The lowest mean Z-score (-1.850) was observed in group III as compared to group I (-1.194) (p < 0.01) and group II (-1.201) (p < 0.05). There were statistically significantly positive correlations between total and spine BMD and BMI. The correlation coefficient was r = 0.56 and r = 0.41 (p < 0.001), respectively. CONCLUSIONS: In the majority of the children (c. 60%), a reduction in bone mineral content was found. The lowest Z-score (-1.850) was revealed in the oldest children, which may disturb the process of reaching the optimum level of the peak bone mass.
PURPOSE: Assessment of the effect of low-calcium diet on bone mineral content in children and adolescents. MATERIAL AND METHODS: The study involved 89 children (49 girls and 40 boys) aged 5-18 years, in whom diseases affecting bony metabolism had been excluded. Children with a history of dietary calcium content below 500 mg/day were recruited. The study group was divided according to age: group I, age 5-9 years (children before puberty); group II, age 9-15 years (early puberty); group III, 15-18 years (late puberty). Dual energy X-ray absorptiometry (DEXA) was used for densitometric measurements. Bone mineral density (BMD) was assessed in the whole skeleton (total BMD), in vertebrae L2-L4 (spine BMD) in g/cm2 and as Z-score. Concentrations of Ca, Ca2, P, activity of alkaline phosphatase (AP) and its bony isoenzyme were determined in the serum. RESULTS: Total bone mass below 5th percentile (according to the norm for age and gender) was found in 56.98% of the children involved in the study. A significant reduction was noted in the spine mineral mass in boys (p < 0.01) as compared to girls (0.731 +/- 0.17 g/cm2 and 0.835 +/- 0.19 g/cm2, respectively). The lowest mean Z-score (-1.850) was observed in group III as compared to group I (-1.194) (p < 0.01) and group II (-1.201) (p < 0.05). There were statistically significantly positive correlations between total and spine BMD and BMI. The correlation coefficient was r = 0.56 and r = 0.41 (p < 0.001), respectively. CONCLUSIONS: In the majority of the children (c. 60%), a reduction in bone mineral content was found. The lowest Z-score (-1.850) was revealed in the oldest children, which may disturb the process of reaching the optimum level of the peak bone mass.