Epidemiology And Etiology

RA affects approximately 1% of the U.S population and 1% to 2% of the world s pop-1 2

ulation. ' RA arises from an immunologic reaction, and there is speculation that it is in response to a genetic or infectious antigen. Risk factors associated with the development of RA include the following:

• Female gender (3:1 females to males)

• Increasing age (peak onset 35-50 years of age)

• Current tobacco smoking. Studies have identified a direct relationship between tobacco use and RA disease severity. Tobacco users also have an increased risk of pulmonary manifestations of RA. This risk is reduced when a patient has remained tobacco-free for at least 10 years.

• Family history of RA. Genetic studies demonstrate a strong correlation between RA and the presence of major histocompatibility complex class II human leukocyte antigens (HLA), specifically HLA-DR1 and HLA-DR445 HLA is a molecule associated with the presentation of antigens to T lymphocytes.

• Potential environmental exposures. The number of RA cases has increased during industrialization, although a specific link to environmental factors has not been de-termined.6

• Oral contraceptive use and high ingestion of vitamin D and tea are associated with a decreased risk of RA.

• Fewer than 300,000 children in the United States under age 16 are affected by JIA. There are no known risk factors for JIA.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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