Reference values for vertebral shape in young Chinese women: implication for assessment of vertebral deformity.

The race- and sex-specific reference values for vertebral shape are important to determine the prevalence of osteoporotic vertebral fracture. However, these reference values are absent in Chinese women. In the present study, the anterior, middle and posterior heights and the ratios of these heights were measured from 14 vertebral bodies (T4-L5) in 60 premenopausal Chinese women (aged 19-25 years). Cutoff values were set as standard deviations (3 and 3.5 SD) and percentages (15 and 20%) below the means of vertebral height (VH) ratios to define vertebral deformities. The number of subjects with a VH ratio lower than -15% cutoff were significantly more than those with a VH ratio lower than -3 SD cutoff (p < 0.05), but this difference did not occur when a -20% cutoff was selected. A few VH ratios were distributed below -20% and -3 SD cutoffs, and none was below -3.5 SD. The vertebral shape defined by VH ratios was different between Chinese and European women. We conclude that 3.5 SD below the reference mean is an ideal cutoff value for the definition of prevalent vertebral fractures in Chinese women, and reference data should be obtained from young premenopausal women.