Much lower prevalence and severity of radiographic osteoporotic vertebral fracture in elderly Hong Kong Chinese women than in age-matched Rome Caucasian women: a cross-sectional study

Abstract

Introduction: Many earlier studies reported that East Asians and Caucasians have similar radiographic osteoporotic vertebral fracture (OVF) prevalence. Since elderly Chinese's osteoporotic hip fracture prevalence is half (or less than half) of that of their age-match Caucasians, we hypothesize that elderly Chinese's OVF prevalence could be only half, or even less than half, of that of their age-match Caucasians.

Materials: Age-matched (mean: 74.1 years; range: 65-87 years) elderly women's radiographs (T4-L5) were from two OVF population-based epidemiological studies conducted in Hong Kong (n = 200) and in Rome (n = 200). All radiographs were double read by one reader in Hong Kong and one reader in Rome. Radiological osteoporotic vertebral deformity (ROVD) classification included no ROVD (grade 0), and ROVDs with < 20%, 20 ~ 25%, ≥ 25% ~ 1/3, ≥ 1/3 ~ 40%, ≥ 40% ~ 2/3, and ≥ 2/3 height loss (grade 1 ~ 6) as well as endplate/cortex fracture (ECF). Spinal deformity index (SDI) was calculated with each vertebra assigned a score of 0, 0.5, 1, 1.5, 2, 2.5, and 3 for no ROVD or ROVDs grade 1 ~ 6.

Results: Seventy-seven (38.5%) Chinese subjects and 123 Italian subjects (61.5%) had ROVD respectively (p < 0.0001). Chinese subjects had ECF in 52 (26%) cases involving 100 vertebrae, while Italian subjects had ECF in 93 (47%) cases involving 230 vertebrae. ROVDs in Italian subjects tended to be more severe (total and mean SDI: 454.5 and 3.71 for Italian, and 212 and 2.72 for Chinese, p < 0.05), more likely to be multiple, more likely to have severe and collapsed grades. The slope of the relationship between age vs. SDI was steeper for the Italian subjects than for the Chinese subjects, suggesting ROVD severity developed faster for aging Italian subjects. A trend suggested earlier onset of ROVD among Italian.

Conclusion: OVFs in Chinese women tend to be less common, less severe, and less likely to have multiple fractures.

Keywords: Osteoporotic vertebral fracture (OVF); Vertebral deformities; Chinese; Italian; Extended semi-quantitative (eSQ) method; Spine deformity index (SDI).