Endocrine Abstracts

Childhood and adolescence represents an important period for accrual of bone mass and therefore changes during this time have a potential influence on adult bone mass and risk of osteoporosis. It is known that between 33 and 46% of adult bone mineral content is accrued over a 4-year period of adolescent growth surrounding peak height velocity. Although genetic factors are the most significant influence, environmental factors such as nutrition, exercise including mechanical loading, and puberty are critical influences with disturbances in these compromising bone density and strength leading to a risk of osteoporotic fractures. The assessment of bone density in children and adolescents is primarily undertaken with the use of dual energy X-ray absorptiometry (DXA) for which there is the availability of normative reference data for UK children. However it is recognised that factors in addition to bone density such as the material property of the bone and bone geometry are important determinants of bone strength which are not captured by DXA. Other imaging modalities are therefore being explored which provide this information. Chronic diseases and/or their treatment occurring during childhood and adolescence can compromise bone strength leading to osteoporotic fractures in either the axial or appendicular skeleton. Inflammatory conditions such as juvenile idiopathic arthritis and crohn’s disease either alone or in conjunction with corticosteroids often compromise trabecular bone in the spine with the potential development of vertebral fractures. Boys with Duchenne muscular dystrophy are at risk of vertebral and long bone fractures due to a combination of corticosteroid treatment and the progressive loss of mobility. The development of hypogonadism in conditions such as thalassaemia major can compromise bone strength if appropriate and timely hormone replacement does not occur. Thus the management of many of these conditions often requires an assessment of bone health to optimise skeletal development during childhood growth.