Osteoarthritis is the most common degenerative disease in the world. As of 2019, about 528 million people globally were living with it, a 113% increase since 1990. It occurs when the cartilage cushioning your joints gradually breaks down, leading to pain, stiffness, and reduced mobility that worsen over time.
Other degenerative diseases like Alzheimer’s and Parkinson’s affect the brain and nervous system, and they carry enormous personal and economic costs. But in terms of sheer numbers, osteoarthritis affects far more people than any other degenerative condition.
How Osteoarthritis Compares to Other Degenerative Diseases
Degenerative diseases are conditions where tissues or organs progressively deteriorate over time. They fall into two broad categories: those affecting the joints and those affecting the nervous system. Osteoarthritis dominates the first category. In the second, Alzheimer’s disease is the most common, affecting an estimated 6.2 million Americans age 65 and older. Parkinson’s disease follows, with nearly one million Americans living with it.
While Alzheimer’s carries staggering economic costs (roughly $1 trillion in global annual costs as of 2022), osteoarthritis still affects roughly 100 times more people worldwide. With aging populations, rising obesity rates, and more sports-related injuries, the World Health Organization expects osteoarthritis prevalence to keep climbing.
What Happens Inside the Joint
Healthy cartilage is a firm, slippery tissue that lets bones glide smoothly against each other. In osteoarthritis, enzymes produced by cartilage cells begin to break down the two main structural proteins that hold cartilage together: collagen (which gives it strength) and proteoglycans (which give it springiness). Your body does produce substances that try to counteract these enzymes, but in osteoarthritis, the destructive side wins out.
The disease progresses through three overlapping stages. First, the cartilage matrix starts to break apart at a molecular level. Second, the cartilage surface develops cracks and begins to erode, releasing fragments into the fluid surrounding the joint. Third, those fragments trigger a chronic inflammatory response in the joint lining. This inflammation then feeds back into more cartilage destruction, creating a cycle that gradually worsens the damage.
This is why osteoarthritis isn’t simply “wear and tear,” as it’s often described. Inflammation plays an active role in driving the disease forward, which is why treatments increasingly target both pain and the underlying inflammatory process.
Who Gets It and Why
Age is the single biggest risk factor. Cartilage naturally thins as you get older, and most people over 70 have at least some symptoms. But osteoarthritis can start much earlier, especially after joint injuries like ACL tears.
In middle age, women are affected more often than men. By around age 70, the gap narrows and both sexes are affected at similar rates. There’s also a genetic component: you can inherit a predisposition to developing osteoarthritis, though the exact inheritance pattern isn’t well understood. Having a family history doesn’t guarantee you’ll develop it, but it does raise your baseline risk.
The most important modifiable risk factors are body weight and joint stress. Carrying extra weight puts more mechanical load on your knees and hips with every step, accelerating cartilage breakdown. Jobs or activities that place repeated stress on specific joints (construction work, long-distance running on hard surfaces, repetitive kneeling) also increase risk significantly.
What It Feels Like as It Progresses
Early osteoarthritis often shows up as stiffness after sitting for a while or aching after physical activity. You might notice that your knees feel stiff in the morning but loosen up within 20 or 30 minutes. At this stage, the pain tends to come and go, and many people dismiss it as a normal part of aging.
As the disease advances, pain becomes more persistent and starts interfering with daily activities. Walking, climbing stairs, gripping objects, or getting in and out of a car can become difficult. Some joints develop bony enlargements (called osteophytes) that you can sometimes feel or see, particularly in the finger joints. In advanced stages, the joint space narrows so much that bones are nearly touching, causing significant pain with even minor movement.
Doctors grade severity on a 0-to-4 scale using X-rays, looking at four key features: narrowing of the space between bones, bony growths at the joint margins, hardening of the bone just below the cartilage, and small cysts forming in that same bone layer. Grade 0 means no osteoarthritis is visible. Grade 4 means severe disease with major structural changes.
How It’s Diagnosed
Diagnosis requires both symptoms and imaging. You need to have pain, aching, or stiffness in the affected joint on most days over at least a six-week period, and those symptoms can’t be better explained by an acute injury or another condition like gout or rheumatoid arthritis. X-rays are essential for confirming the diagnosis, since they reveal the structural changes in bone and joint space that distinguish osteoarthritis from other causes of joint pain.
Your age, how long your morning stiffness lasts, and whether the joints showing symptoms match the joints showing damage on X-rays all factor into the formal diagnosis. There’s no single blood test for osteoarthritis, which sometimes makes it harder to catch early.
How Osteoarthritis Is Managed
There’s no cure for osteoarthritis, but a combination of strategies can slow progression and significantly reduce pain. The 2026 clinical guidelines for knee osteoarthritis place three approaches at the foundation of every treatment plan: patient education, exercise programs, and weight management. These aren’t optional add-ons. They’re considered the mainstay for all patients regardless of disease severity.
Exercise might seem counterintuitive when your joints hurt, but strengthening the muscles around a joint reduces the load on the cartilage itself. Low-impact activities like swimming, cycling, and walking are particularly effective. Losing even a modest amount of weight, if you’re carrying extra, can meaningfully reduce both pain and the rate of cartilage loss in weight-bearing joints.
When lifestyle changes aren’t enough on their own, topical anti-inflammatory creams applied directly to the skin over the joint are the first medication recommended. They work locally with fewer side effects than pills. If topical options don’t provide relief, short courses of oral anti-inflammatory medications can help, though these carry higher risks for the stomach, kidneys, and cardiovascular system with extended use.
For people whose pain persists despite these approaches, corticosteroid injections directly into the joint can offer short-term relief. Acupuncture has also gained recognition as an option for those who haven’t responded well to conventional treatments. When the disease has progressed to the point where it significantly limits daily function and quality of life, joint replacement surgery becomes a realistic and often highly effective option, particularly for the knee and hip.
Alzheimer’s Disease: The Leading Neurodegenerative Condition
While osteoarthritis tops the overall degenerative disease list, Alzheimer’s disease is the most common degenerative condition affecting the brain. It deserves attention here because many people searching for “degenerative disease” are thinking about neurological conditions.
Age is the dominant risk factor. Among people aged 65 to 74, about 4 out of every 1,000 develop Alzheimer’s each year. That rate jumps to 32 per 1,000 for those aged 75 to 84, and 76 per 1,000 for people 85 and older. The increase is dramatic: you’re roughly 19 times more likely to develop Alzheimer’s at 85 than at 65.
Women are disproportionately affected. Almost two-thirds of Americans with Alzheimer’s are women. A European meta-analysis found that roughly 13 women per 1,000 developed Alzheimer’s each year, compared to 7 men. The reasons aren’t fully understood, though differences in lifespan, hormonal changes after menopause, and possible genetic factors all likely play a role.
The global economic burden of dementia (of which Alzheimer’s accounts for the majority) reached an estimated $948 billion in 2016 and is projected to hit $2 trillion by 2030. That figure represents about 2% of the entire world’s economic output, reflecting both the cost of care and the lost productivity of patients and their caregivers.