Reference ranges for vertebral heights and prevalence of asymptomatic (undiagnosed) vertebral fracture in Vietnamese men and women

Based on quantitative measurements of vertebral heights, the prevalence of undiagnosed vertebral fracture in Vietnamese men and women aged 50 years and older was 23 and 26 %, respectively.The present study sought to develop reference ranges for vertebral heights and to determine the prevalence of asymptomatic vertebral fracture in Vietnamese men and women.The study included 312 men and 657 women aged over 18 who were randomly selected from the community. The ImageJ software program was used to measure anterior height (H(a)), middle height (H(m)), and posterior height (H(p)) for each vertebra (T4 to T12 and L1 to L5). Four vertebral ratios were determined: H(a)/H(p), H(m)/H(p), H(p)/H(p + 1), and H(p)/H(p − 1). Reference ranges for the ratios were then developed by the method of Winsorized mean. Vertebral fracture was diagnosed as a ratio lower than three standard deviations from the normal mean.For any given vertebra, H(a), H(m), and H(p) in men were higher than in women. In both sexes, H(a) and H(m) increased in a stepwise fashion from T4 to L3 and then gradually reduced in L4–L5. Vertebral heights for T4–T9 tended to decrease, while vertebral height for T10–L5 tended to increase with advancing age. Among those aged over 50 years, the prevalence of vertebral fracture in men was 23.3 % (95 % confidence interval (CI) 16.8–31.3 %) which was lower than that in women (26.5 %; 95 % CI 22.4–31.1 %). The prevalence increased with advancing age, such that from the age of over 70, 41 % of men and 42 % women had at least one vertebral fracture.One fourth of Vietnamese men and women aged 50 years and older have a symptomatic vertebral fracture. This prevalence is equivalent to that in Caucasian populations.