OBJECTIVES: The aim of this study was to identify sex-specific prevalence and strength of risk factors for the incidence of radiographic knee OA (incRKOA).
METHODS: Our study population consisted of 10 958 Rotterdam Study participants free of knee OA in one or both knees at baseline. One thousand and sixty-four participants developed RKOA after a median follow-up time of 9.6 years. We estimated the association between each available risk factor and incRKOA using sex stratified multivariate regression models with generalized estimating equations. Subsequently, we statistically tested sex differences between risk estimates and calculated the population attributable fractions (PAFs) for modifiable risk factors.
RESULTS: The prevalence of the investigated risk factors was, in general, higher in women compared with men, except that alcohol intake and smoking were higher in men and high BMI showed equal prevalence. We found significantly different risk estimates between men and women: high level of physical activity [relative risk (RR) 1.76 (95% CI: 1.29-2.40)] or a Kellgren and Lawrence score 1 at baseline [RR 5.48 (95% CI: 4.51-6.65)] was higher in men. Among borderline significantly different risk estimates was BMI ≥27, associated with higher risk for incRKOA in women [RR 2.00 (95% CI: 1.74-2.31)]. The PAF for higher BMI was 25.6% in women and 19.3% in men.
CONCLUSION: We found sex-specific differences in both presence and relative risk of several risk factors for incRKOA. Especially BMI, a modifiable risk factor, impacts women more strongly than men. These risk factors can be used in the development of personalized prevention strategies and in building sex-specific prediction tools to identify high risk profile patients.
The Rotterdam Study is funded by Erasmus Medical Center and Erasmus University, Rotterdam, Netherlands Organization for the Health Research and Development (ZonMw), the Research Institute for Diseases in the Elderly (RIDE), the Ministry of Education, Culture and Science, the Ministry for Health, Welfare and Sports, the European Commission (DG XII) and the Municipality of Rotterdam. The authors are grateful to the study participants, the staff from the Rotterdam Study and the participating general practitioners and pharmacists. All authors contributed substantially to the conception and design of the article. I.S. performed the analysis and drafted the initial manuscript. All authors critically revised it for interpretation of results and important intellectual content. All authors approved the final version of the manuscript.
Funding: This research was funded by The Netherlands Organization for Health Research and Development (ZonMw), project number 849200003.
Disclosure statement: S.M.A.B.-Z. declares doing consultancy for Pfizer (tanezumab) and reports grants from The Netherlands Organization for Health Research and Development (ZonMw), Dutch Arthritis Association, Foreum. The remaining authors declare no competing financial interests. All authors declare no non-financial conflicts of interest.
© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology.