Читать книгу Arthritis For Dummies - Barry Fox - Страница 29

Just as many different kinds of arthritis exist, many different causes also exist — and some of them are still unknown. But in general, scientists have found that certain factors can contribute to the development of joint problems:

 Heredity: Your parents gave you your beautiful eyes, strong jawline, exceptional math ability, and, possibly, a tendency to develop rheumatoid arthritis. Scientists have discovered that the genetic marker HLA-DR4 is linked to rheumatoid arthritis, so if you happen to have this gene, you’re more likely to develop the disease. Ankylosing spondylitis is linked to the genetic marker HLA-B27, and although having this gene doesn’t mean that you absolutely will get this form of arthritis, you can — if conditions are right.

 Age: It’s just a fact of life that the older you get, the more likely you are to develop arthritis, especially osteoarthritis. Like the tires on your car, cartilage can wear down over time, becoming thin, cracked, or even wearing through. Bones may also break down with age, bringing on joint pain and dysfunction.

 Overuse of a joint: What do ballerinas, baseball pitchers, and tennis players all have in common? A great chance that they’ll develop arthritis due to the tremendous repetitive strain they put on their joints. The dancers, who go from flat foot to pointe hundreds of times during a practice session, often end up with painful arthritic ankles. Baseball pitchers, throwing fastballs at speeds of more than 100 mph, regularly develop arthritis of the shoulder and/or elbow. And you don’t need to be a tennis pro to develop tennis elbow, a form of tendonitis that has sidelined many a player.

 Injury: Sustaining injury to a joint (from a household mishap, a car accident, playing sports, or doing anything else) increases the odds that you may develop arthritis in that joint in the future. Football players are well-known victims of arthritis of the knee, which is certainly not surprising: They often fall smack on their knees or other joints when they’re tackled — then have a ton of “football flesh” crash down on top of them. What’s most amazing is that they ever walk away uninjured.

 Infection: Some forms of arthritis are the result of bacteria, viruses, or fungi that can either cause the disease or trigger it in susceptible people. Lyme disease comes from bacteria transmitted by the bite of a tick. The most common cause of bacterial infectious arthritis is a Staphylococcus aureus (staph) infection. Staph commonly lives on the skin and can cause infectious arthritis when it enters the body during surgery or trauma, or when a needle is inserted into a joint. It can also result from bone infection or an infection that’s traveled from another area of the body. Infection typically strikes in the knee, but can also affect the wrists, ankles and hips. It usually affects only one joint.Obesity: Carrying too much weight is a big risk factor for OA because it puts undue pressure on the joints, especially the knees, and can cause the cartilage that cushions the joints to wear away faster. Just 10 extra pounds of body weight increases the pressure exerted on your knee joints by 40 pounds every time you take a step on flat ground. Add an incline or a trip up or down some stairs and the pressure easily doubles if not triples. Fat is also a chemically active tissue that constantly releases proteins which cause inflammation. This can increase the likelihood that OA will develop, and can worsen inflammation-related forms of arthritis such as RA, gout, and ankylosing spondylitis.

 Tumor necrosis factor-alpha (TNF-alpha): TNF-alpha (usually just known as TNF, which we’ll use in this book) is a substance the body produces that causes inflammation and may play a part in initiating or maintaining rheumatoid arthritis. Although scientists are unsure exactly what triggers RA, they have found that drugs that counteract the effects of TNF-alpha, called TNF inhibitor, are often helpful in managing the symptoms of this disease