Improved estimates of global prevalence and incidence of knee osteoarthritis (OA) can be used to assess health burden, according to study results published in EClinical Medicine, an open-access clinical journal by the Lancet. Study authors noted that the general public, health care providers, and policymakers should be aware of the high prevalence of knee OA and the modifiable risk factors including obesity, injury, and education.

Although knee OA is a major cause of disability in the elderly, few studies have estimated its global prevalence, incidence, and risk factors.

In a systematic review and meta-analysis, the study authors sought to estimate the global and regional prevalence and incidence of knee OA, as well as identify the risk factors.

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Of the 88 studies included in the current analysis, 18 were published between 2017 and 2020. Based on study findings, the global prevalence of knee OA was 16% (95% CI, 14.3%-17.8%) among individuals aged 15 years or over and 22.9% (95% CI, 19.8%-26.1%) among those aged 40 years or over. Further, approximately 654.1 million (95% CI, 565.6-745.6 million; aged ≥40 years) individuals worldwide had knee OA in 2020.

The global incidence of knee OA was 203 per 10,000 person-years (95% CI, 106-331 per 10,000 person-years) in individuals aged 20 years or over. Correspondingly, approximately 86.7 million (95% CI, 45.3-141.3 million) individuals aged 20 years or over had incident knee OA worldwide in 2020. The ratios of prevalence and incidence of knee OA in women and men were 1.69 (95% CI, 1.59-1.80; P <.00) and 1.39 (95% CI, 1.24-1.56; P <.00), respectively.

Regarding risk factors for knee OA, study results demonstrated that the prevalence and incidence increased with age, peaking at the advanced age on prevalence, and at 70 to 79 years of age on incidence. Further, increased education attainment was negatively associated with the prevalence of knee OA.

Study limitations included statistically significant heterogeneity, the inability to differentiate prevalence of knee OA and ethnicity, and the lack of assessment of prevalence of knee OA in individual countries due to the limited number of original studies.

Study authors concluded, “More efforts should be made to explore the cause of the high prevalence and incidence of knee OA in women and elderly and provide effectively preventive strategies in the early stages of the disease.”


Cui A, Li H, Wang D, Zhong J, Chen Y, Lu H. Global, regional prevalence, incidence and risk factors of knee osteoarthritis in population-based studies. EClinicalMedicine. 2020;29:100587. doi:10.1016./j.eclinm.2020.100587