There are more than 100 different diseases that fall under the umbrella of arthritis. State figures, however, are available only for those diseases targeted in the BRFSS survey, i.e., arthritis (osteoarthritis), rheumatoid arthritis, gout, lupus, and fibromyalgia. For this reason, only those types of AORC are described below.
The most common form of arthritis is osteoarthritis (OA), also known as “wear and tear” or degenerative arthritis. It is estimated that approximately 10% of people in the United States are affected by osteoarthritis, rising to 70% to 90% of people older than 75. OA is caused by the gradual degeneration of joint cartilage, which normally acts to cushion the bones in a joint. Healthy cartilage replaces itself, a process that is disrupted when osteoarthritis sets in. When the cushion of cartilage disappears, the bones can thicken and often produce bone spurs that protrude into the joint, causing inflammation and subsequent pain and stiffness. Osteoarthritis is most commonly found in the knees, hips, hands, and spine (spondylosis, or degeneration of the intervertebral disks).
The etiology of OA is multifactorial. Age is the greatest risk factor for OA, with scientists now also suggesting a genetic susceptibility to the disease. Women are more likely than men to report the disease overall, although men have a higher incidence under the age of 45. Obesity is a major risk factor, especially for OA in the hips and knees. A trauma to the joint, through sports or other injuries, also increases the risk of arthritis in that joint.
Prolonged occupational stress can also increase the risk. Physical inactivity, or immobilization of a joint, can increase the likelihood of developing OA. In addition, arthritis can result from infections caused by bacteria (especially staph and strep), viruses, or fungi that migrate to a joint and cause inflammation. For example, Lyme disease, an infection caused by a bacterium spread by deer ticks, results in arthritis in about 60% of sufferers if left untreated.
Lupus is an autoimmune disease in which the immune system attacks healthy cells and tissues in various parts of the body, most particularly the joints, skin, blood, and kidneys. Lupus is an autoimmune disease in which the immune system attacks healthy cells and tissues in various parts of the body, most particularly the joints, skin, blood, and kidneys.
The most common form of lupus is systemic lupus erythematosus (SLE), which accounts for about 70% of all cases. This is the type of lupus that affects the joints; 90% of people diagnosed with SLE will suffer joint pain during the active periods of the illness. Discoid lupus, the second most common form, affects only the skin, but nearly 10% of discoid lupus cases will eventually progress to SLE.
SLE causes a wide variety of symptoms in addition to joint inflammation and pain, including fever, fatigue, skin rashes, loss of hair, loss of appetite, high blood pressure, and swelling of the feet and legs. Symptoms vary among individuals, as does the severity of the disease. In some people, lupus will go into remission for periods of time, while other people have symptoms continuously.
SLE is 8 to 10 times more likely to develop in women than in men, occurring most frequently during the childbearing years. It is 3 times more prevalent among African Americans and also more likely to occur among Hispanics, Asians, and Native Americans than among Caucasians (18). Twenty percent (20%) of people diagnosed with lupus have a parent or sibling with the disorder (18). As with other forms of arthritis, scientists suggest that a viral or bacterial infection might trigger the onset of the disease in individuals with a genetic susceptibility. Pregnancy can sometimes trigger the onset of lupus, or cause a flare-up in women who have the disease.
(FM) is characterized by pain, stiffness, and tenderness in the joints, muscles, and tendons. These symptoms are accompanied by sleep problems, fatigue, and anxiety. Patients suffer generalized aching and pain and have multiple tender points (areas of localized pain when pressure is applied) located in the neck, spine, shoulders, hips, and knees. A diagnosis of FM is made when pain has persisted for longer than three months and the patient has pain in 11 of the 18 specific tender point areas. The National Institute of Arthritis and Musculoskeletal and Skin Diseases estimates that approximately 3.7 million Americans have FM, but other estimates run as high as 8 million (19).
Fibromyalgia does not cause the inflammation found in the other types of arthritis discussed above. Because of this, damage to the joints or internal organs of the body and/or joint deformities are not part of this disease.
Researchers have found a higher incidence of sleep apnea and restless leg syndrome in fibromyalgia patients, suggesting that inadequate sleep may be a possible contributor to the condition. Other studies suggest that low levels of the stress hormone cortisol are associated with fibromyalgia.
Fibromyalgia is diagnosed most frequently in women of childbearing age but can also occur among men and younger and older women. The disease is more common among people who have a family history of fibromyalgia or other pain-related disorders.
Juvenile Rheumatoid Arthritis
Juvenile Rheumatoid Arthritis (JRA) accounts for up to 70% of arthritis diagnosed in children. JRA has a prevalence rate of approximately 1.1 cases per 1,000 children. There are three subtypes of JRA: (a) pauciarticular, involving pain and inflammation in less than five joints within three months of onset; (b) polyarticular, involving five or more joints within three months of onset; and (c) systemic, involving a high-grade fever and other non-joint-related symptoms at the onset, but with major joint involvement as the disease progresses.
JRA typically presents between the ages of six months and 16 years. Pauciarticular JRA, which accounts for about 50% of all cases, occurs more frequently among girls than boys; girls under the age of eight are the most likely to be diagnosed with this type of JRA. It most often affects the large joints, such as the knees. Some children outgrow pauciarticular disease, but symptoms can recur.
Polyarticular JRA accounts for approximately 30% of cases and is also diagnosed more frequently in girls than in boys. This type of JRA most commonly affects the small joints, such as those in the hands and feet.
Systemic JRA can affect internal organs such as the heart and liver as well as the joints in the same way as adult RA. It is diagnosed equally among boys and girls.
Juvenile rheumatoid arthritis is an autoimmune disease, as is rheumatoid arthritis among adults. The immune system attacks healthy cells and tissues, resulting in pain, swelling, and heat around the joints. Scientists suspect a genetic tendency toward the disease, triggered by a bacterial or viral infection. JRA onset has been linked to the rubella virus and enteric (intestinal) bacterial infections, among others, but research continues to investigate this relationship.
Rhemeutoid arthritis (RA), the most common connective tissue disorder, is a chronic autoimmune disorder. It occurs in approximately 1% to 2% of the population and is two to three times more likely to be diagnosed in women than in men, often developing in women between the ages of 30 and 50. Among the elderly, men and women are equally likely to develop RA.
Gout accounts for about 5% of all arthritis cases, affecting close to 1 in 30 Americans. It is one of the most painful of all rheumatic diseases. Gout results when deposits of uric acid crystals locate in different parts of the body, most frequently the joints. Uric acid crystals form when there is an excess of uric acid (hyperuricemia) built up in the body. This can result from the body producing too much uric acid or not excreting enough of the acid through the kidneys.
The big toe is the most common site of gout (about 75% of patients), but the ankle, knee, wrist, hand, elbow, and foot can also be affected. The crystal deposits cause inflammation in the joint, resulting in pain and swelling, often with sudden onset. Men are four times more likely to develop gout than women, with onset rare before age 30 and most frequently between 40 and 50. Women are more likely to develop gout after the age of 60.
Acute gout attacks can be triggered by such traumatic events as surgery or heart attacks. Gout often runs in families, suggesting a genetic predisposition to the condition. Up to 18% of individuals who have gout have a family history of the disease. Certain medications, particularly those used to treat high blood pressure such as diuretics, can cause a gout attack, as can alcohol use. Animal-based foods high in a substance called purine, e.g., red meat and seafood, can trigger gout. Gout is more prevalent in countries with a high standard of living, perhaps because of diet. Obesity is also a risk factor for developing gout. In addition, exposure to lead in the environment has been suggested as a risk factor for gout by the Agency for Toxic Substances and Disease Registry, U.S. Department of Health and Human Resources (16). All these factors are thought to interfere with the ability of the body to adequately excrete uric acid.
In many cases, gout can be controlled through proper treatment. Early attacks usually subside after 3 to 10 days, even with no treatment, and subsequent attacks may not occur for months or years. However, later attacks may last longer and occur more often.