Impaired bone health and asymptomatic vertebral compressions in fracture-prone children: a case-control study

Abstract

Frequent fractures in children may be a sign of impaired bone health, but it remains unestablished when and how fracture-prone children should be assessed. This prospective study elucidated skeletal characteristics and predisposing factors in children with recurrent fractures. Findings were used to establish guidelines for screening. During a 12-month period we recorded fracture history for all children (n = 1412) treated for an acute fracture at a large university hospital. All apparently healthy children over 4 years of age, who had sustained: (1) at least one vertebral fracture; (2) two long-bone fractures before age 10 years; or (3) three long-bone fractures before age 16 years, were recruited. They underwent dual-energy X-ray absorptiometry (DXA), laboratory tests, and spinal radiography. Information regarding family history and lifestyle factors were collected. Findings were compared with healthy controls. Sixty-six fracture-prone children (44 males, mean age 10.7 years; 5% of all children with fractures) were identified. Altogether, they had sustained 183 long-bone fractures (median 3, range 0–7); 11 children had sustained vertebral fracture(s). Patients had significantly lower bone mineral density (BMD) at lumbar spine (p < 0.001), hip (p = 0.007), and whole body (p < 0.001) than the controls; only 5 children (8%) had a BMD Z-score < −2.0. Asymptomatic vertebral compressions were prevalent, especially in those under 10 years of age. Hypercalciuria (11%) and hyperphosphaturia (22%) were significantly more prevalent than in controls. Serum concentration of 25-hydroxyvitamin D (S-25OHD) was below 50 nmol/L in 55%; low levels were associated with low BMD and vertebral compressions. The fracture-prone children had lower calcium intake, less physical activity, and more often had siblings with fractures than the controls. The findings suggest that a thorough pediatric evaluation, including DXA and spinal radiography, is often indicated already after a second significant low-energy fracture in children, in order to detect potentially preventable adverse lifestyle factors and nutritional deficits and to identify those with compromised overall bone health.