Morphology and Prevalence Study of Lumbar Scoliosis in 7,075 Multiracial Asian Adults

Background: Lumbar scoliosis affects patients' quality of life and will increasingly burden the health-care system as the population ages, yet there have been few reports of its prevalence in Asians. The aim of this study was to identify the prevalence of scoliosis, curve characteristics, and risk factors for development of scoliosis in an Asian population. Methods: A retrospective cross-sectional study was conducted using spinal images obtained from dual x-ray absorptiometry (DXA) scans of individuals >= 40 years of age. Scoliosis was defined as a curvature of >10 degrees. A multivariate analysis for risk factors for development of lumbar scoliosis was performed. Results: Of 7,075 patients studied, 645 (9.1%) were identified as having scoliosis. The average age of the patients with scoliosis was 61 years (range, 40 to 98 years). The mean curve prevalence was 9.4% in women and 6.5% in men. The average Cobb angle was 16.5 degrees (range, 10 degrees to 66 degrees). Multivariate analysis showed an increased risk of scoliosis in women (relative risk [RR] = 2.4, 95% CI = 1.4 to 4.3), Chinese patients (RR = 2.4, 95% CI = 1.4 to 4.3), Malay patients (RR = 2.5, 95% CI = 1.3 to 4.9), and patients with spinal fracture (RR = 5.1, 95% CI = 3.0 to 8.8). The risk of scoliosis was found to increase as patients progressed through each decade of life after the age of 40 years (6th decade: RR = 1.6, 95% CI = 1.1 to 2.4, p = 0.026; 7th decade: RR = 2.7, 95% CI = 1.8 to 4.1, p < 0.001; 8th decade: RR = 5.0, 95% CI = 3.2 to 7.9, p < 0.001; and 9th decade: RR = 8.8, 95% CI = 4.3 to 17.9, p < 0.001). Conclusions: The prevalence of lumbar scoliosis in Asian adults was found to be 9.1%. A nearly exponential increase in scoliosis prevalence from the 5th decade of life (4%) to the >= 9th decade (25%) and a majority of left-sided scoliotic curves, measuring between 10 degrees and 19 degrees with an L2 apex, was found. Older age, female sex, Chinese or Malay race, and vertebral fracture increased the risk of scoliosis developing.