The Two Main Types of Arthritis Have Different Causes

Osteoarthritis happens when the protective cartilage that cushions your joints wears down over time. This is the most common type, especially as people age. The cartilage breakdown can start from years of use, injury to a joint, or extra weight putting pressure on your knees, hips, and lower back.

Rheumatoid arthritis is different — it is an autoimmune disease, meaning your immune system mistakenly attacks the lining of your joints. This causes inflammation, swelling, and pain. Unlike osteoarthritis, rheumatoid arthritis can develop relatively quickly and often affects both sides of your body at the same time (both hands, both knees).

A few other types exist — like gout, lupus-related arthritis, and psoriatic arthritis — but osteoarthritis and rheumatoid arthritis account for the vast majority of cases in older adults.

Key Takeaways

  • Osteoarthritis develops when joint cartilage wears down from age, injury, or repeated stress, and is the most common form in seniors.
  • Rheumatoid arthritis is an autoimmune condition where your body attacks joint linings, causing inflammation and often affecting joints on both sides of your body.
  • Risk factors for osteoarthritis include age over 50, previous joint injuries, excess weight, and family history.
  • Rheumatoid arthritis is more common in women and can run in families, though the exact trigger is not fully understood.
  • Some people have both types of arthritis at the same time, which requires different treatment approaches.

Age and Wear-and-Tear Lead to Osteoarthritis

Osteoarthritis develops slowly as the cartilage in your joints breaks down. Cartilage is the smooth, rubbery tissue that lets bones slide past each other without friction. Over decades, this cartilage can thin and crack, especially in joints you use constantly — your knees, hips, hands, and spine.

The longer you live, the more likely osteoarthritis becomes. Most people over 65 have some cartilage loss visible on X-rays, though not everyone has pain or symptoms. The wear happens faster if you have had a serious joint injury (a torn knee ligament, a broken bone in a joint, or a bad fall), because the joint may not heal perfectly and cartilage can break down unevenly from that point on.

Extra body weight speeds up osteoarthritis in weight-bearing joints. Each pound of extra weight puts roughly three to six pounds of pressure on your knees when you walk, so carrying extra weight for years can wear cartilage faster than it would otherwise.

Autoimmune Attack Causes Rheumatoid Arthritis

Rheumatoid arthritis starts when your immune system mistakenly identifies the lining of your joints (called the synovium) as a threat and attacks it. This triggers inflammation — swelling, warmth, redness, and pain. Over time, this inflammation can damage the cartilage and bone underneath, causing permanent joint damage if not treated.

The exact reason your immune system turns against your own joints is not fully understood. Researchers believe a combination of genetics and an environmental trigger (possibly a viral infection or exposure to something in the environment) sets it off. If your parent or sibling has rheumatoid arthritis, your risk is higher, but having the gene does not may provide you will develop it.

Rheumatoid arthritis is more common in women than men, and it often starts between ages 40 and 60, though it can develop at any age. Unlike osteoarthritis, it can come on fairly quickly — sometimes over weeks or a few months — and typically affects the same joints on both sides of your body.

Family History and Genetics Play a Role

Both types of arthritis run in families. If your parent or sibling has osteoarthritis, you are more likely to develop it, especially in the same joints. This does not mean you will definitely get it, but your genes influence how quickly your cartilage breaks down and how your body handles joint stress.

Rheumatoid arthritis has a stronger genetic link. Certain genes make your immune system more likely to attack joint tissue. A blood test can check for these genes (called HLA markers), though many people carry the genes without ever developing the disease. An environmental trigger — possibly a respiratory infection, smoking, or exposure to certain bacteria — may be needed to set up the disease in people who carry the genes.

Other Factors That Increase Your Risk

Several habits and circumstances make arthritis more likely. Smoking increases your risk of rheumatoid arthritis significantly and can also speed up osteoarthritis. A sedentary lifestyle (not moving much) weakens the muscles around your joints, which puts more stress on the cartilage itself. Conversely, high-impact activities over many years — like running on hard surfaces or heavy manual labor — can wear cartilage faster.

Previous injuries to a joint raise your risk of osteoarthritis in that specific joint, sometimes years or decades later. A torn knee meniscus, a broken bone that heals imperfectly, or a ligament tear can all lead to uneven wear on cartilage. Hormonal changes may also play a role; some research suggests that lower estrogen levels after menopause increase osteoarthritis risk in women.

Certain infections and other diseases can trigger arthritis-like symptoms or actual arthritis. Lyme disease, hepatitis C, and some other infections can cause joint inflammation. Conditions like lupus and psoriasis can also cause arthritis as part of the disease.

What Arthritis Is Not Caused By

Cold weather does not cause arthritis, though many people with arthritis report that their pain gets worse in cold, damp weather. The change in barometric pressure may affect joint fluid, but cold itself does not damage cartilage or trigger autoimmune attacks.

Cracking your knuckles does not cause arthritis. Studies have found no link between knuckle cracking and joint damage, despite the common belief. Arthritis develops from the causes listed above — cartilage wear, autoimmune attack, or other disease — not from the sounds your joints make.

When to Talk to Your Doctor About Joint Pain

See your doctor if you have joint pain that lasts more than a few weeks, swelling that does not go down after resting and icing, or stiffness that is worst in the morning and takes more than 30 minutes to improve. These are common signs that something is changing in your joints.

Tell your doctor if you have a family history of arthritis, especially rheumatoid arthritis. Mention any previous joint injuries, your weight, and whether you smoke. If you notice pain in the same joints on both sides of your body (both hands, both knees), that is a red flag for rheumatoid arthritis and should be checked sooner rather than later.

Your doctor may order blood tests (to check for rheumatoid factor or other markers) or imaging like X-rays or ultrasound to see what is happening in your joints. Early diagnosis of rheumatoid arthritis is especially important because treatment started early can slow or stop joint damage.

Frequently Asked Questions

Can you get arthritis from using your hands too much?

Repetitive use can contribute to osteoarthritis in the joints you use most, but it is not the only cause. Years of typing, gripping, or fine detail work may speed up cartilage wear if you already have risk factors like age or family history. Rest, stretching, and proper ergonomics can help, but arthritis develops from the underlying causes listed above, not from activity alone.

Does arthritis skip generations?

Arthritis can appear to skip generations because genes are inherited unpredictably and environmental triggers matter. You might inherit the genes for arthritis from a grandparent but not develop it yourself if you do not have the right combination of age, weight, injury history, or environmental exposure. Conversely, you might develop arthritis without a close family member having it.

Is arthritis worse in men or women?

Rheumatoid arthritis is two to three times more common in women, especially after menopause. Osteoarthritis affects men and women roughly equally overall, though women may develop it earlier in weight-bearing joints after menopause. Hormonal changes, genetics, and immune system differences all play a role in these patterns.

Can you prevent arthritis if it runs in your family?

You cannot may provide prevention if you carry the genes, but you can reduce your risk. Maintain a healthy weight, stay physically active with low-impact exercise, avoid smoking, and protect your joints from injury. If you have a family history of rheumatoid arthritis, talk to your doctor about monitoring for early signs, since early treatment can prevent joint damage.

What is the difference between arthritis pain and normal joint pain?

Normal joint pain from overuse usually improves within days with rest and ice. Arthritis pain is persistent — lasting weeks or months — and often comes with swelling, warmth, stiffness (especially in the morning), or pain in the same joints on both sides of your body. If pain does not improve after a week of rest, or if it is getting worse, see your doctor.