Biochemical markers of bone and collagen turnover have been found to be a v
aluable adjunct to measurements of bone mineral density in post-menopausal
women in whom they appear to be independent predictors of osteoporosis and
fracture risk. In children, they have been less extensively studied but hav
e begun to find a similar complementary role in a number of disorders affec
ting bone turnover and growth. Although they may give helpful information i
n their reflection of recent bone turnover and growth in various disorders,
their principal value appears to be in giving an early and sensitive indic
ation of response to treatment, before changes in either height velocity or
bone mineral density can be accurately determined. This review discusses t
he use and limitations of these markers in children, the clinical condition
s in which they have been studied and their potential value in monitoring e
ither beneficial or adverse effects of treatment on bone turnover and growt
h.