Osteoarthritis is common in all races and backgrounds. It usually appears after age 45. Men under age 55 are more likely to have OA than women in the same age range. After age 55, however, women are more commonly affected. Overall, more women have osteoarthritis than men. One possible reason: Women’s broader hips may put more long-term stress on their knees.
What Causes Osteoarthritis?
Despite the prevalence of the disease, the causes of osteoarthritis are not completely understood. There is no cure. Many different factors may play a role in whether or not you get OA:
Age. Incidences of osteoarthritis increase with age due to simple “wear and tear” on the joints – the older you are, the more you have used them. However, that doesn’t mean OA is an inevitable part of aging because not everyone gets it.
Obesity. Increased body weight, which adds stress to lower body joints, is a well established factor in the development of osteoarthritis. Your knees, which carry the brunt of your weight, are particularly at risk. For every pound you gain, you add 4 pounds of pressure on your knees and six times the pressure on your hips. Gaining weight as you head toward middle age can increase the likelihood of developing OA. Recent research suggests that excess body fat produces chemicals that travel throughout the body and cause joint damage, which would mean obesity plays a systemic, not just a mechanical, role in osteoarthritis onset.
Injury or Overuse. Athletes and people whose jobs require repetitive motion, (landscaping, typing or operating machinery), have a higher risk of developing osteoarthritis due to injury and increased stress on certain joints. Soft tissue injuries, such as ACL tears, can lead to OA; it can also appear in joints affected by previous bone fractures and surgeries.
Genetics or Heredity. Genetics plays a role in the development and progression of osteoarthritis, particularly in the hands. Inherited bone abnormalities that affect joint shape or stability or defects that cause cartilage to form abnormally can lead to OA. It’s also more common in joints that don’t fit together smoothly, such as those of people who are bowlegged or double jointed. Having these traits, however, doesn’t mean you’ll develop osteoarthritis. It just means that you and your doctor should keep an eye out for arthritis signs and symptoms.
Muscle Weakness. Studies show that weakness of the muscles surrounding the knee is associated with OA, especially in women, and makes the pain and stiffness worse after onset. Strengthening exercises for thigh muscles are important in reducing the risk.