Sex- and age-specific disparities in low back pain burden attributable to three modifiable risks, 1990–2021: A cross-sectional analysis of the global burden of disease study 2021

Low back pain (LBP) is the leading cause of global disability, with more than 500 million cases reported in 2020, and its risk patterns vary across regions and demographic groups. Using Global Burden of Disease 2021 data, Disability-Adjusted Life Years (DALYs) attributable to 3 risk factors were analyzed across 204 countries. Age-standardized rates (ASRs) and temporal trends average annual percentage change (AAPC) were calculated. From 1990 to 2021, DALYs attributable to high body mass index (BMI) increased from 3.09 million to 8.36 million, while the ASR increased by 39%, disproportionately affecting high- sociodemographic index (SDI) regions (115.59 per 100,000 in 2021). ASRs attributable to occupational ergonomic factors and smoking declined by 19% and 33%, respectively, although absolute DALYs increased with population growth. Occupational ergonomic factors remained the leading contributor in 2021, particularly in low-income regions and Eastern Sub-Saharan Africa (ASR, 342.78 per 100,000). East Asia had the largest decline (AAPC = -1.43), whereas Oceania had the largest increase (AAPC = 1.07). Kiribati and Paraguay had the largest increases in occupational-related LBP, whereas Ethiopia and Moldova had the largest declines. Smoking-related DALYs declined in most regions but increased in Eastern Europe (AAPC = 0.18). Central Latin America and Southern Sub-Saharan Africa had the steepest declines (AAPC = -1.79 and -1.62, respectively). South Africa and Madagascar had the largest reductions in smoking-related LBP (AAPC = -1.94 and -2.05), whereas Uzbekistan and Mali had notable increases (AAPC = 0.70 and 1.00). The 50 to 54-year age group had the highest DALY burden across all 3 risk factors. However, DALYs attributable to high BMI peaked among females aged 70 to 74 years, whereas those attributable to occupational ergonomic factors peaked at 50 to 60 years and smoking-related DALYs at 60 to 69 years. Females had higher BMI- and occupation-attributable DALYs, whereas males had higher smoking-attributable burdens. SDI was strongly correlated with risk patterns: high BMI (R = 0.671) and smoking (R = 0.721) burdens increased with SDI, whereas occupational factors were inversely correlated with SDI (r = -0.414). The growing LBP burden is increasingly attributable to high BMI, particularly among aging populations and in high-SDI regions, whereas declining occupational and smoking risks obscure persistent disparities in low-income areas.