Osteoarthritis
What causes it?
While there isn’t any single known cause of osteoarthritis (OA), there are several risk factors that should be considered. Knowing and controlling these risk factors can help you minimize your risk or even help you prevent getting OA altogether. Keep in mind that having risk factors for OA doesn’t mean you will definitely get it. No single risk factor is enough to cause OA; it is more likely that a combination of risk factors works together to cause the disease.
There are two distinct types of osteoarthritis – primary and secondary. Primary osteoarthritis is the type associated with aging and is thought of as “wear and tear” osteoarthritis. The older you are, the more likely it is that you will have some degree of primary arthritis. In fact, if we live long enough, most of us will experience primary osteoarthritis, even if it is just a touch. There is no apparent cause for this type of osteoarthritis.
In contrast, when someone is diagnosed with secondary osteoarthritis, it is because there is an apparent cause for the disease. In other words, the breakdown of cartilage can be associated to injury, heredity, obesity or something else.
Listed below are the risk factors for osteoarthritis.
- Age. Incidences of OA increase as you age. Since “wear and tear” does play a part in the development of OA, the older you are, the more you have used your joints. Although age is an important risk factor, it doesn’t mean that OA is inevitable.
- Obesity. Obesity is a nationwide epidemic and you hear about the danger from it every day on the news. Increased body weight is a serious factor in the development of OA, particularly in your knees, which carry the brunt of your weight day in and day out. For every pound you gain, you add 3 pounds of pressure on your knees and six times the pressure on your hips. Since weight gain gradually increases the stress on joints, the weight you gain the decade before you have OA symptoms, particularly in middle age, plays a big role in determining if you will have OA.
- Injury or Overuse. Athletes and people who have jobs that require doing repetitive motion, such as landscaping, typing or machine operating, have a higher risk of developing OA due to injury and increase stress on certain joints. OA also develops in later years in joints where bones have been fractured or surgery has occurred. It is important for athletes to learn to take precautions to avoid injury and for people in repetitive jobs to modify their movements to lessen this stress. Note: Avoiding repetitive movement shouldn’t be interpreted as not exercising. Regular moderate exercise strengthens the joint causing it to be more stable, thereby, reducing the risk of OA in that joint.
- Genetics or Heredity. It is becoming more and more clear that genetics plays a role in the development of OA, particularly in the hands. This shows itself in many ways. Inherited abnormalities of the bones that affect the shape or stability of the joints can lead to OA. It is also more common in joints that don’t fit together smoothly. For example, a bowlegged person is more likely to develop OA. Increased laxity or being double jointed also increases the risk of OA. Recently, researchers have been looking at a defect in the gene responsible for manufacturing cartilage as a risk factor. Just because you have one of these inherited traits, doesn’t mean that you are going to develop OA. It just means that your doctor should check you more closely and more frequently for signs and symptoms of the disease.
- Muscle Weakness. Studies of the knee muscles not only show that weakness of the muscles surrounding the knee can lead to OA, but that strengthening exercises for thigh muscles are important in reducing the risk.
- Other Diseases and Types of Arthritis. People with rheumatoid arthritis tend to have a greater chance of developing OA. Also, hemochromotosis, or having too much iron, can damage cartilage to the point of chronic deterioration. Acromegaly, or excess growth hormone, also has adverse affects on the bones and joints and can lead to OA.
