The global prevalence of joint diseases is substantial and rising, affecting hundreds of millions of people worldwide with significant variation depending on the specific disease type, age group, gender, and geographic region. Among joint diseases, osteoarthritis (OA), particularly knee osteoarthritis (KOA), stands out as the most common and burdensome condition globally.
Osteoarthritis affects over 650 million individuals worldwide, with knee osteoarthritis accounting for nearly 80% of this burden. The prevalence of KOA has been increasing steadily over the past few decades, driven largely by population growth, aging demographics, and lifestyle factors. From 1990 to 2021, the global incidence and prevalence of KOA increased by approximately 1.3 to 1.4 times, with age-standardized rates rising by 7 to 8 percent. This trend is projected to continue, with the number of affected individuals expected to grow further by 2035. Middle-aged and elderly populations (aged 45 and above) are disproportionately affected, and women consistently show higher incidence rates than men. The disease causes significant disability, contributing to years lived with disability (YLDs) and long-term pain and physical limitations worldwide.
The burden of osteoarthritis is not evenly distributed. Countries with higher socioeconomic development tend to have a higher prevalence of KOA, although disparities between nations are gradually decreasing. In lower-income regions, underdiagnosis and limited access to healthcare may mask the true prevalence. For example, in Pakistan, community-based studies estimate that 14% to 20% of the population suffers from OA, with knee OA affecting roughly one in four adults in both urban and rural areas. However, many cases remain unreported due to barriers such as cost, distance, and lack of awareness.
Other joint diseases also contribute to the global burden but with lower prevalence rates compared to osteoarthritis. Psoriatic arthritis (PsA), an inflammatory joint disease often associated with psoriasis, has a worldwide prevalence estimated around 0.1% to 0.25% of the general population. The prevalence varies widely depending on geographic location and study methodology, with estimates ranging from as low as 3.3 per 100,000 to as high as 461.5 per 100,000 in different populations. Psoriatic arthritis typically affects adults between 35 and 55 years of age and presents diagnostic challenges due to its heterogeneous symptoms.
Other forms of joint diseases, including rheumatoid arthritis, gout, and secondary joint diseases caused by infections or metabolic disorders, also contribute to the global prevalence but generally affect smaller proportions of the population compared to osteoarthritis.
Age is a critical factor influencing the prevalence of joint diseases. Osteoarthritis prevalence increases sharply with age, with clinical and radiological signs becoming more common in people over 50 years old. For example, hand and hip osteoarthritis show increasing frequency in older age groups, with radiological evidence often exceeding clinical symptoms. Women tend to have higher rates of joint diseases, particularly post-menopause, which may be related to hormonal changes affecting joint health.
The rising global prevalence of joint diseases poses significant challenges for healthcare systems worldwide. These diseases lead to chronic pain, reduced mobility, loss of productivity, and increased healthcare costs. Joint replacement surgeries and other interventions are becoming more common but remain inaccessible to many in low-resource settings.
In summary, joint diseases, especially osteoarthritis, represent a major and growing global health issue. The prevalence is influenced by demographic shifts, socioeconomic factors, and healthcare access disparities. Understanding these patterns is essential for developing effective prevention, diagnosis, and management strategies to reduce the burden of joint diseases worldwide.