effects of L-thyroxin replacement therapy on bone mineral and body composition in hypothyroid children

This study aimed to detect the effects of L-T4 treatment on bone mineral and body composition in hypothyroid children, Thirty five hypothyroid patients [10 males and 25 females], mean age was 11.57 +/- 5.06 yr. Twenty six children of matched age and sex served as controls, Dual energy X-ray absorptiometry [DXA] was done to detect the bone mineral density [BMD], bone mineral content [BMC] and Z score at lumbar and femur neck regions. Body composition was also studied by DXA. Serum calcium, phosphorus, osteocalcin, osteoprotegrin and urinary deoxypyridinoline were measured. No significant differences were detected in lumbar Z score [-0.19 +/- 0.65] and femur Z score [-0.16 +/- 0.57] compared to controls [-0.33 +/- 0.75] and [-0.21 +/- 0.53] respectively. BMD and BMC are not significantly different from controls. No significant difference was detected between cases and controls as regard body composition. Positive correlation was detected between BMD and age [r 0.857, P<0.01], and with the period of treatment [r=0.766, P<0.01]. Positive correlation was existed between BMD and total body fat [r=0.693, P<0.01], and with abdominal fat [r=0.667, P<0.01]. L-T4 treatment in hypothyroid children doesn't alter bone metabolism and body composition