What Are The Risk Factors For Developing Osteoarthritis?
There Are Numerous Risk Factors
The exact reason that Osteoarthritis occurs is not known. However, there are many combinations of factors (being overweight, the aging process, joint injury or stress, heredity, muscle weakness) that can increase the risk of developing Osteoarthritis. The disease can be classified broadly into two categories based on the factors involved:
- Primary Osteoarthritis- Occurs mostly as a result of aging when degenerative cartilage changes occur within a joint. Heredity is also considered a primary cause of OA.
- Secondary Osteoarthritis- Occurs as a result of another by a disease or condition. The conditions that can cause secondary Osteoarthritis include abnormal joints at birth (congenital abnormalities), possible hormone disorders, obesity, joint damage, excessive stress on joints or surgery to the joint.
These factors are classified as either generalized or localized risk factors.
Generalized Risk Factors: are more systemic in nature, affecting the entire body, and include age, obesity, gender, and genetics/ethnicity.
Age: is the most common generalized risk factor for developing OA. As a person ages, the chances of developing Osteoarthritis in all joints increases until the age of 70. Although age is a strong factor in the development of OA, it is uncommon before the age of 40. The strong association between age and Osteoarthritis may be best explained by the changes in the joint cartilage that occur with time. These changes cause a loss of cartilage function which prevents the normal reparative processes in the joint. This leads to an increased risk for loss of cartilage injury to the joint.
Being Obese: Has been identified as the most important factor in the progression of OA especially of the Knee. An increase in weight places additional stress on load bearing joints such as the knee. This additional weight automatically increases the chance for developing OA. In addition to the physical strain that obesity places on the joints, there is also a metabolic component to obesity, which increases the risk for the progression of OA. Studies have found that excessive amounts of fatty tissue, termed adipose tissue, result in the release of specific hormones and growth factors. Excess fatty tissue may predispose joints to the development of OA and may also cause progression of OA that already exists. Lastly, being obese can make the pain associated with hip and knee Osteoarthritis more severe.
Vitamin Deficiency-Inappropriate Diet: A poor diet can be a risk factor for the progression of Osteoarthritis, because certain vitamin deficiencies can influence the progression of the disease. In studies that examined levels of vitamin D in the blood, it was determined that patients with low levels of Vitamin D had three times the risk for the progression of OA. In another study, low levels of vitamin C were also associated with the progression of OA. However, although studies have found low levels of certain vitamins can affect the progression of OA, this does not mean that low levels of certain vitamins will cause the development of OA.
Being Female: Science has shown that women are more susceptible to obesity the men, and because obesity is an important risk factor for OA, women are therefore at greater risk for developing OA. In addition to obesity, other factors, such as females hormones lead to the development of OA. Because the presence of certain hormones is associated with OA, and the type and amount of hormones differ between men and women, specific types of OA affect only women. For example, Menopausal OA, also known has Nodal Generalized OA, is caused by hormone level fluctuation and its onset is consistent with the beginning of menopause. The tendency of specific types of OA and the prevalence of obesity in women is the reason why being female can be considered a risk factor for OA.
Family History/Genetics: Osteoarthritis can be found in several members of the same family suggesting heredity may play a role. In fact, it has been suggested that up to 60% of OA casesresult from genetic factors. Studies conducted on Nodal Generalized OA have revealed this particular type of OA has a strong hereditary component in the development of OA of the hip and knee. It is believed that mutations in specific genes are linked to the development of OA. However, the particular gene involved had not been identified.
Ethnicity: The occurrence of OA in specific joints also varies according to race. For example, in comparison to Caucasians, Blacks and Asians are less commonly afflicted with OA of the hip, and black Africans and Malaysians are less commonly afflicted with OA of the hand. These differences seen across different races suggest that race may be an important risk factor in developing OA in certain joints.
Allergies and Infections: There has been some research that examined the possibility of an allergy or an infection can lead to the development of OA, however, at this point there is little evidence to support this idea.
Localized Risk Factors: Can result from a congenital (you are born with it) defect, a history of surgery, or a previous injury to the joint.
Wear and Tear:
OA is often referred to as ’wear and tear’ arthritis. However this is not completely accurate because normally joints are exposed to small amounts of stress through daily activities and are able to repair themselves without causing OA. In Osteoarthritis, the body’s natural repair process does not work properly during normal wear and tear activities of daily life. Wear and tear activities will only cause a progression of OA if the joint was abnormal in some way such as a congenital defect, previous injury, etc.
Joint Injury or Surgery:
Osteoarthritis can develop in a joint if it has been previously damaged by injury. If a fracture is not properly set the bones heal badly and the neighbor joints are put to abnormal stress leading to osteoarthritis. Sometimes osteoarthritis is caused by injury and damage from a different kind of joint disease that occurred years before. For example, people with rheumatoid arthritis can develop ‘secondary’ osteoarthritis in those joints in which the rheumatoid inflammation has largely burnt out but where the joint remains damaged by the disease.
Congenital Defect (you are born with it):
People who are born with abnormally formed or misaligned joints, those whom have injured a joint, or those whom have had surgical alteration to a joint are all at greater risk for the development of OA. In a joint that is abnormal, regardless of the cause of the defect, increased mechanical load, whether it is the result of heavy lifting or repetitive movement is a risk factor for OA.