**Background:** Low back pain is a highly prevalent condition and the leading cause of years lived with disability (YLDs) globally. This study presents the most up-to-date estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021, covering prevalence and YLDs for low back pain from 1990 to 2020, with projections to 2050.
**Methods:** Population-based studies from 1980 to 2019 were identified via systematic review of Ovid MEDLINE, Embase, CINAHL, and PubMed, along with international surveys, US medical claims data (ICD-9 code 724; ICD-10 codes M54.3, M54.4, M54.5), and collaborator-contributed datasets. Low back pain was defined as pain between the 12th ribs and gluteal folds lasting at least 1 day. Data using alternative definitions were adjusted via network meta-regression (MR-BRT). Nested Bayesian meta-regression models (DisMod-MR 2.1) estimated prevalence and YLDs by age, sex, year, and location for 204 countries and territories. Prevalence was projected to 2050 using a regression on prevalence rates with Socio-demographic Index (SDI) as a predictor, multiplied by projected population estimates. A Das Gupta decomposition analysis assessed contributions of population growth, aging, and prevalence changes to projected case increases.
**Key Results:** In 2020, low back pain affected 619 million (95% UI 554–694) people globally, a 60.4% increase from 1990. The global age-standardized prevalence rate in 2020 was 7460 per 100,000 (6690–8370), a decrease of 10.4% (10.9–10.0) from 1990. The global age-standardized YLD rate was 832 per 100,000 (578–1070), a decrease of 10.5% (11.1–10.0) from 1990. Low back pain accounted for 69.0 million (47.9–88.9) YLDs in 2020, representing 8.1% (6.7–9.5) of all-cause YLDs, making it the leading cause of YLDs globally. The highest age-standardized prevalence rates were in central Europe (12,800 per 100,000), eastern Europe (11,200), and Australasia (11,100); the lowest were in east Asia (5,430). Prevalence was higher in females (age-standardized rate 9,330 per 100,000) than males (5,520), and increased with age, peaking at approximately 85 years. The age group 80–84 years had the highest YLD rate (2,440 per 100,000). A total of 38.8% (28.7–47.0) of YLDs were attributable to three modifiable risk factors: occupational ergonomic factors (22.0%; 20.4–23.4), smoking (12.5%; 3.1–21.5), and high BMI (11.5%; 1.4–20.9). By 2050, the number of prevalent cases is projected to reach 843 million (759–933), a 36.4% increase from 2020. The greatest contribution to this increase comes from population growth, followed by population aging, though in some regions (e.g., east Asia, south Asia) aging is the primary driver.
**Clinical Implications:** Low back pain remains the leading cause of disability worldwide, with more than half a billion prevalent cases in 2020 and a projected rise to over 800 million by 2050. The modest decline in age-standardized rates over three decades is outweighed by population growth and aging, particularly in Asia and Africa. The high burden in working-age populations has substantial economic consequences, including lost workdays and premature retirement. The significant attributable fractions for occupational factors, smoking, and high BMI highlight potential targets for prevention, though evidence for effective preventive strategies remains limited. The findings emphasize the urgent need for high-quality primary country-level data, especially from low- and middle-income countries, and for implementation of evidence-based, guideline-concordant care to reduce inappropriate use of imaging, opioids, and invasive procedures.