Sex-Specific Trends in the Prevalence of Osteoarthritis and Rheumatoid Arthritis from 2005 to 2021: A Nationwide Cross-Sectional Study in South Korea

Background: Osteoarthritis  and rheumatoid arthritis (RA) are prevalent chronic joint disorders,  with prevalence rates varying by sex. However, few studies have  comprehensively documented the factors contributing to the sex-specific  prevalence of osteoarthritis and RA, including sociological factors and  the impact of the COVID-19 pandemic.

Objective: This  study aims to identify long-term trends in the sex-specific prevalence  of osteoarthritis and RA from 2005 to 2021 while examining the factors  that serve as vulnerabilities specific to each sex within the context of  the COVID-19 pandemic.

Methods: Data  were collected from a nationally representative sample of 110,225  individuals through the Korea National Health and Nutrition Examination  Survey from 2005 to 2021. The study included patients aged 19 years and  older diagnosed with osteoarthritis or RA in South Korea. Data were  analyzed using weighted trends to accurately represent the sample  population, with a 95% CI. Weighted logistic and regression models were  used to identify vulnerable groups at risk of osteoarthritis or RA  during the pandemic to assess sex-specific trends.

Results: In  total, 110,225 individuals (n=48,410, 43.92% male participants) were  analyzed from 2005 to 2021, with prevalence rates remaining stable over  time and higher in female than in male participants. Notably, during the  pandemic, female participants aged 60 years and older exhibited a  prevalence of osteoarthritis that was 4.92 times greater than male  participants and a prevalence of RA that was 6.44 times greater  (osteoarthritis: prevalence ratio [PR] 69.78, 95% CI 41.66-116.88; RA:  PR 17.27, 95% CI 8.75-34.07). In terms of osteoarthritis, male  participants did not show a significant association with BMI (PR 1.40,  95% CI 1.21-1.61; P=.47), whereas female participants exhibited a  significantly higher vulnerability within the obese group (PR 1.68, 95%  CI 1.55-1.83; P<.001). Regarding RA, lower education levels  were associated with increased vulnerability, with male participants  showing a greater risk than female participants (male participants: PR  2.29, 95% CI 1.61-3.27 and female participants: PR 1.50, 95% CI  1.23-1.84).

Conclusions: This  study reveals that women in South Korea have a higher prevalence of  osteoarthritis and RA than men. Understanding these sex-specific trends  and identifying vulnerability factors can enhance preventive efforts and  patient care.