What Causes Osteoarthritis?
Arthritis is characterized by chronic inflammation of one or more joints in the body, with osteoarthritis (OA) being the most common type. In individuals with OA, the cartilage within one or more joints gradually deteriorates over time.
Cartilage is a tough, rubbery substance that normally protects the ends of bones and allows joints to move smoothly. As the cartilage degenerates, the smooth surfaces of the bones within the joints become pitted and rough, causing joint pain and irritating the surrounding tissues. Over time, the cartilage may erode completely, leading to bones rubbing directly against each other, which can result in severe pain.
While some cartilage degradation is a natural part of aging, not everyone develops OA. The reasons why one person may develop the condition while another similar individual does not are not well understood. The specific causes of OA can vary from person to person.
Risk Factors for Osteoarthritis
Certain factors are known to increase the risk of developing OA. Some of these factors are beyond your control, but you can mitigate your risk by addressing lifestyle factors such as:
- Overuse of joints
- Obesity
- Poor posture
Family History
OA sometimes runs in families. If your parents or siblings have OA, you are more likely to develop it as well. While the exact reasons why OA runs in families remain unknown, and no specific gene has been identified as the cause, genetic factors may contribute to the risk of developing OA.
Age
Osteoarthritis (OA) is closely linked to the wear and tear on joints, becoming more prevalent as people age. According to the Centers for Disease Control and Prevention, over one-third of adults aged 65 and older have symptoms of OA.
Gender
OA can affect both men and women, but its prevalence varies by age and gender. According to the National Institutes of Health, OA is slightly more common in men until around age 45. After that, it becomes more common in women, possibly due to different joint stressors experienced by each gender over time.
Previous Injury
Individuals who have previously injured a joint are at a higher risk of developing OA in that joint.
Obesity
Excess weight places increased stress and strain on the body’s joints, raising the risk of OA. Overweight or obese individuals are particularly susceptible to OA in the:
- Knees
- Hips
- Spine
However, obesity is also linked to OA in non-weight-bearing joints, such as those in the hands. This suggests that factors beyond just mechanical stress or weight alone may contribute to OA risk.
Certain Occupations
Repetitive actions can exert undue stress on joints, and jobs requiring such actions can increase OA risk. Job tasks that may fall into this category include:
- Kneeling or squatting for more than an hour a day
- Lifting
- Climbing stairs
- Walking
Individuals who regularly participate in joint-intensive sports may also face an increased risk of developing OA.
Poor Posture
Improper sitting or standing positions can strain your joints, thereby increasing the risk of OA.
Other Types of Arthritis
Certain other types of arthritis can elevate your risk of developing osteoarthritis (OA) later in life. These include:
- Gout
- Septic arthritis
- Rheumatoid arthritis
Other Medical Conditions
Medical conditions that influence joint health can also affect your risk of developing OA. For instance, bleeding disorders can lead to bleeding in the joints, while conditions that impact blood flow or promote inflammation can also elevate risk. Some medical conditions associated with OA include:
- Osteonecrosis
- Paget’s disease of bone
- Diabetes
- Gout
- Hypothyroidism (underactive thyroid)
Osteoarthritis Triggers
Not everyone with OA experiences symptoms continuously. Most individuals have symptoms that fluctuate throughout the day. While specific triggers for OA symptoms can vary from person to person, some common ones include:
Lack of Activity
Remaining still for extended periods can cause your joints to stiffen, making movement more painful. This inactivity, especially overnight, may partly explain why OA pain is often worse upon waking.
Stress
Research has shown a link between stress and increased perceptions of pain.
Weather Changes
Variations in weather can exacerbate OA symptoms. Individuals with OA are often particularly sensitive to cold, damp conditions.