Radiograph-based study of gender-specific vertebral area gain in healthy children and adolescents as a function of age, height, and weight.

This study reports gender-specific vertebral area gain data from children and adolescents. Vertebral area was measured on lateral and anteroposterior thoracic and lumbar spine radiographs from 100 female and 100 male subjects aged 7-28 yr. T9, T11, T12, L1, and L2 X-ray area calculation was based on calculation of the area of the geometric figure of a trapezoid whose 2 nonparallel sides were equal in length, taking account of the waisted shape of the vertebrae. Both the boys and girls of our study population showed statistically significant dependence (p<0.001) of vertebral area gain on chronologic age, height, and weight right through the end of puberty, and especially so up to age 15 yr. However, height and weight were clearly better predictors of lateral and anteroposterior vertebral area gain than was chronologic age. Once vertebral growth is complete by age 18 yr or so, the lateral vertebral areas of the male subjects-regardless of body weight and height-are, on average, 25% larger, and the anteroposterior areas up to 30% larger than those of their female counterparts. After adjusting for chronologic age, height, and weight however we did not find significant differences, between gender, in vertebral area of male and female subjects, neither among children younger than 11 yr nor adolescents ages of 12-14 yr and young adults older than 18 yr.