The silent epidemic in sacred lands: knee osteoarthritis burden from high-frequency ritual kneeling, 1990–2021

BACKGROUND: Knee osteoarthritis (KOA) disproportionately affects populations practicing high-frequency ritual kneeling during religious/cultural activities, inadequately explained by conventional risk models. METHODS: Using Global Burden of Disease 2021 data from 34 countries, we analyzed KOA prevalence, incidence, and disability-adjusted life years (DALYs). Age-standardized rates were computed via Bayesian meta-regression (DisMod-MR 2.1). Temporal trends (1990-2021) were assessed using estimated annual percentage change and Bayesian age-period-cohort modeling, linking biomechanical and cultural factors to sex/region-specific burden. RESULTS: Countries with daily ritual kneeling exhibited KOA burdens exceeding global averages. Saudi Arabia (Islamic) showed a 500% female age-standardized prevalence rate (ASPR) increase since 1990 (4496.9 per 100 000 in 2021). Mexico (Catholic) and Thailand (Buddhist) reported female ASPRs of 4970.4 and 4386.1 per 100 000, respectively-48.7% higher than males in Thailand. Elevated female incidence (Thailand: 364.9; Mexico: 402.5 per 100 000) and DALYs (Thailand: 141.5 per 100 000) likely reflect the interplay of biological vulnerabilities, longevity, and cultural practices. Biomechanical factors correlated positively with KOA severity. CONCLUSION: Ritual kneeling is strongly associated with elevated KOA burden, likely mediated by biomechanical stress, cultural practices, and sex-specific vulnerabilities. Findings suggest the potential benefit of faith-sensitive interventions to mitigate disability while respecting traditions, aligning with WHO healthy aging goals. Key messages • What is already known on this topic Knee osteoarthritis (KOA) is a leading cause of global disability, but conventional risk models do not adequately explain the high prevalence observed in populations where frequent ritual kneeling is a common cultural or religious practice. While localized studies have suggested a link, the global burden attributable to this specific biomechanical stressor remained unquantified. • What this study adds • This study provides the first global epidemiological analysis using Global Burden of Disease 2021 data to suggest that high-frequency ritual kneeling is a significant potential risk factor for KOA. • It quantifies the burden across 34 countries, revealing that nations with daily kneeling practices experience KOA prevalence and disability rates significantly exceeding global averages. • How this study might affect research, practice or policy These findings underscore the need to integrate cultural and religious factors into public health strategies for chronic disease prevention. This evidence points to the potential utility of "faith-sensitive" interventions-such as promoting cushioned mats, chair-assisted worship, or collaboration with religious leaders-to mitigate preventable disability while respecting sacred traditions.