Causes and Risk Factors of Arthritis

Arthritis is a disease that causes inflammation and pain around your joints (places where two bones meet). There are many types of arthritis, and each type can have a different cause.

The most common type of arthritis is osteoarthritis. This type of arthritis causes the joint tissue to wear down over time. Osteoarthritis is more than normal wear and tear on your joints. Typically, an event or reason triggers these changes.

Sometimes, a forceful, traumatic injury can wear down the cartilage in the affected area and trigger osteoarthritis. Obesity may also lead to a breakdown of the joint area because there’s more pressure on your joints. Having surgery on a joint can also cause joint changes. Or, if your joints aren’t formed correctly, they may rub in a way that wears down the area faster than what’s typical and causes osteoarthritis to develop.

Your immune system may play a role in arthritis development.

Rheumatoid arthritis (RA), ankylosing spondylitis, and psoriatic arthritis (PsA) are types of arthritis considered autoimmune diseases. An autoimmune disease is a condition that causes your body to mistakenly identify your healthy tissue as a threat and attack the tissue. This causes inflammation that can trigger arthritis.

While the exact cause is unknown, it’s believed that juvenile idiopathic arthritis (JIA), a type of arthritis that affects children, may also be caused by the autoimmune system attacking healthy tissue.

Gout is a type of arthritis that causes pain and tenderness. It most commonly affects the big toe. Gout is caused by urate crystals that build up in the joints. Urate is an organic compound that may trigger inflammation in the body. It’s broken down in the body from dietary purine, a chemical compound found in alcohol, meat, seafood, sugar, and alcohol.

There is a link between infections and arthritis. Reactive arthritis and septic arthritis are two types of arthritis that can develop following an infection.

Reactive arthritis can cause mild to severe joint pain and stiffness. The arthritis symptoms may be felt in your heel, Achilles tendon, hip, knee, ankle, or lower back. Reactive arthritis may also cause inflammation of the eyes and skin, as well as the urinary and genital systems. In reactive arthritis, the joint itself is not infected; the arthritis is a response to an infection somewhere else in the body.

Septic arthritis causes joint pain after a fungal or bacterial infection. This happens when the joint is directly infected, or an infection spreads to the joint through the bloodstream. Recent surgeries, like joint replacements, or medications that weaken your immune system can increase your risk of developing septic arthritis.

Lyme disease, gonorrhea, Staphylococcus infection, respiratory infections, and tonsillitis are some infections linked to arthritis.

Researchers believe some types of arthritis can be hereditary. For example, up to 60% of RA cases can be linked to genetics, specifically the HLA class II genes. You’re more likely to have RA if you have the genes within the HLA class II family. The remaining 40% of cases of RA are linked to environmental triggers that cause the gene to turn itself on and become a physical trait.

Ankylosing spondylitis has a strong link to HLA-B27, which is in a different HLA class than the RA gene. The HLA genes coordinate your body’s immune response, but the separate genes within the class are responsible for different types of cells. If a biological parent, sibling, or child has ankylosing spondylitis and the HLA-B27 gene, you have a 20% chance of developing ankylosing spondylitis.

Chromosome 5q31 is responsible for some of the genes that cause RA, PsA, and ankylosing spondylitis.

More than 100 different DNA variants have been linked to osteoarthritis. These DNA variances may be responsible for about 20% of the genetic material influencing your risk of developing arthritis. One of the most prominent genetic proteins, COMP, has been strictly linked to Icelandic heritage.

Not all arthritis is hereditary, including arthritis caused by infections.

Some people are more likely to develop arthritis than others.

• Sex: People assigned male at birth have a higher chance of developing gout. People assigned female at birth have a higher chance of experiencing osteoarthritis and RA.
• Age: Older adults may have a higher risk of arthritis because of increased swelling and loss of muscle. About 40% of people over the age of 70 develop osteoarthritis.
• Military service: People in the military are more likely to have arthritis due to injuries they experienced while serving. About a third of veterans have arthritis.
• Ethnicity: People with European or Native American ancestry have a higher chance of developing RA. Asian people have a lower risk.
• Education: Having received less education may be linked to RA. Researchers believe this may be because people might not have learned about the importance of health screenings.
• Economic status: Research shows that people with a lower economic status may have a higher chance of developing RA. This may be due to certain work and living conditions.

There are several risk factors that may make you more prone to developing certain types of arthritis. Some risk factors are modifiable, which means you can change them to lower your risk of developing arthritis. Other risk factors can’t be changed.

Infections

Rheumatoid arthritis and ankylosing spondylitis are autoimmune disorders. Autoimmune disorders can be triggered by certain infections. Sometimes, the pathogen causing an infection can mimic the appearance of healthy cells in your body.

The look-alike pathogen can confuse your immune system, leading the system to mistake your healthy cells for pathogens. When this happens, your immune system may accidentally attack your healthy cells instead unhealthy ones, causing the infection. This could trigger a type of arthritis caused by an autoimmune disorder.

Diet

What you eat may affect your chance of developing arthritis. People with lower levels of marine omega-3 fatty acids have a higher chance of developing rheumatoid arthritis. Omega-3 fatty acids decrease inflammation and improve joint health. You can lower your risk of RA by eating fatty fish regularly.

If you have gout, eating seafood may actually increase your risk of experiencing a gout flare. Seafood is rich in purines, which break down to uric acid and form hardened crystals on the affected joints. Avoid anchovies, sardines, scallops, and mussels to lower your chance of experiencing a gout flare.

Other foods that may increase your risk of experiencing RA or gout include:

• Processed meats
• Refined grains
• Food high in sugar or salt
• Red meat
• Alcohol

Researchers believe these foods may increase inflammation.

Lifestyle Habits

Certain lifestyle habits can increase your risk of developing arthritis.

Your stress levels can increase the amount of inflammation in your body. It can also leave you with a weakened immune system, which can cause infections and potentially lead to arthritis.

One reason stress can weaken your immune system is a lack of sleep. Disrupting your circadian rhythm can alter your immune system and cause inflammation. This can not only activate arthritis but also make your symptoms worse. Reduced sleep also leaves you vulnerable to infections.

Poor sleep and increased stress can cause weight gain. If you have obesity, your body may have chronic inflammation. This can further increase your chance of becoming sick and cause lasting changes to your immune system, putting you at risk for arthritis.

If you smoke, you’re much more likely to develop RA. Smoking causes prolonged stress to your body and your immune system. It prompts certain cells to die and leads to widespread inflammation.

Joint Injury

If you injure your joints, you may be likelier to develop osteoarthritis later in life. These injuries can change the cartilage in your knee.

If you’ve injured your anterior cruciate ligament (ACL)—a band of tissue that helps stabilize your knee joint—you have a higher chance of experiencing osteoarthritis. Falls and work-related injuries are common causes of joint injuries. These events can compromise your connective tissue and the elasticity in your joint, which are classic risks of osteoarthritis.

Arthritis is a disease caused by both genetics and environmental conditions. The cause of your arthritis can determine which type of arthritis you have. Certain risk factors can increase your chance of developing arthritis, including your age, occupation, and history of infection.

Risk factors can sometimes be addressed, but not always. Addressing modifiable risk factors may help lower your risk of developing arthritis, even if you have a gene predisposing you to the condition.