Study of lumbar spine bone mineral density in obese children.

Bone mineral density (BMD) was studied in 59 obese children (mean (+/- SD) age 11.8 +/- 2.7 years) at the start of dietary treatment and compared with a control group, matched for sex, age and body height. Determinations of BMD were made at the level of the lumbar spine (L2-4) by a commercial dual photon absorptiometer (Novolab 22A). Mean (+/- SD) BMD of the obese children (0.68 +/- 0.12 g hydroxy appetite/cm2 (gHA/cm2)) was similar to that of the control group (0.70 +/- 0.16 gHA/cm2). As in normal children, BMD of obese children was highly correlated with age (r = 0.70), body height (r = 0.65) and body weight (r = 0.55). The highest values for BMD were found in obese adolescents with the most advanced pubertal status. No sex difference in BMD was seen in the obese children when pubertal stage was taken into account. Lumbar spine BMD corrected for age, was not related to the degree or duration of obesity. No influence of physical activity on spinal mineralization could be demonstrated in the obese group. In conclusion, obese children present with normal lumbar spine BMD.