Bone mineral density and turnover in children with attention-deficit hyperactivity disorder receiving methylphenidate

Attention-deficit hyperactivity disorder (ADHD) is the most common behavior disorder among children; methylphenidate is a drug frequently prescribed for the control of its symptoms. One of the potential side effects of methylphenidate that concerns parents is its impact on the growth of children, since the mechanism by which methylphenidate might influence growth is not known. As linear growth is associated with an increase in bone mineral density and turnover, this study was undertaken to evaluate bone mineral density by dual photon absorptiometry and bone turnover by measuring serum bone-specific alkaline phosphatase and the urinary deoxypyridinoline excretion rate in children treated with methylphenidate for 1 to 2 years as compared to a control group. There were no significant differences in bone mineral density at either the lumbar spine or femoral neck in the study group (0.662 +/- 0.04 and 0.735 +/- 0.07 g/cm2, respectively) as compared to the controls (0.675 +/- 0.05 g/cm2 and 0.734 +/- 0.07 g/cm2, respectively). Furthermore, there were no significant differences in serum bone-specific alkaline phosphatase in the study group (58 +/- 22 U/L) as compared to the control children (71 +/- 34 U/L) or in urinary deoxypyridinoline in the study group (34 +/- 38 nM/mM), as compared to the control group (27 +/- 12 nM/mM). In conclusion, our data do not support a significant effect of methylphenidate on bone mineral density turnover in children when used for 1 to 2 years.