Evaluation of the usefulness of a quantitative ultrasound device in screening of bone mineral density in children

Background : Osteoporosis is a major public health problem, and its prevention is of great importance. It is known that bone mass later in life is determined by the peak bone mass acquired during adolescence and the subsequent rate of bone loss. Therefore we should give special attention to children that are 'at risk' of low bone mass, and we must seek simple yet reliable methods to measure their bone mineral density (BMD) regularly. Aim : We investigated the value of a quantitative ultrasound device (QUS), the Sahara clinical bone sonometer (Hologic), in screening of low bone mass in children. In contrast to dual energy X-ray absorptiometry (DEXA), the most commonly used technique for measurement of BMD today, the QUS method is free of ionizing radiation, easy to handle and inexpensive. Subjects and methods : Intra- and inter-observer variability of the QUS method was assessed using replicate measurements by two observers in 15 randomly chosen children. QUS parameters were measured in 226 healthy schoolchildren (121 boys, 105 girls) as well as in 41 children at risk for low bone mass (15 boys, 26 girls) between 7 and 18 years old. For comparison we also determined BMD by DEXA in those children at risk. Results : Reproducibility of the QUS device was moderate, as well as the correlation between QUS and DEXA ( r = 0.14-0.50). The QUS device was not able to recognize children with low bone mass as determined by DEXA. Although it is well known that BMD increases with age and pubertal stage, we could not find significant differences in QUS parameters between age and pubertal stage groups. Conclusion : We conclude that there is enough evidence that the Sahara clinical bone sonometer is not useful in screening of low bone mass in children.