Conclusion
OA is the commonest joint disease worldwide and mainly occurs in later life. It tends to be slowly progressive and can cause significant pain and disability. Symptoms and radiographic changes are poorly correlated and thus defining it for research purposes is challenging. Established risk factors include obesity, local trauma and occupation. These may explain some of the geographic variation seen. There is conflicting evidence regarding the roles of nutrition, smoking and sarcopenia. Interestingly, low BMD appears to be protective.
The burden of OA is physical, psychological and socioeconomic. It can be associated with significant disability, such as a reduction in mobility and activities of daily living. Psychological sequelae include distress, devalued self-worth, and loneliness. Given the high frequency of OA in the population, its economic burden is large.