Causes and Risk Factors:

Gout is classified as either primary or secondary, depending on what causes the high levels of uric acid in the blood (hyperuricemia).

More than 99% of primary gout cases are referred to as idiopathic, meaning that the cause of the hyperuricemia cannot be determined. Primary gout is most likely the result of a combination of genetic, hormonal, and dietary factors. Secondary gout is caused by drug therapy or by medical conditions other than a metabolic disorder.

The following factors increase your risk for gout:

• Advancing age
• Male gender
• Family history of the condition
• Obesity
• Use of certain drugs, including diuretics ("water pills"), low-dose aspirin, cyclosporine, or levodopa
• Binge drinking
• Lead toxicity
• Organ transplants
• Thyroid problems
• Other serious illness

Each risk factor is discussed in more detail below.

Age

Middle-Aged Adults. Gout usually occurs in middle-aged men, peaking in the mid-40s. It is most often associated in this age group with obesity, high blood pressure, unhealthy cholesterol levels, and heavy alcohol use.

Elderly. Gout can also develop in older people, when it occurs equally in men and women. In this group, gout is most often associated with kidney problems and the use of diuretics. It is less often associated with alcohol use.

Children. Except for rare inherited genetic disorders that cause hyperuricemia, gout in children is rare.

Gender

Men. Men are significantly at higher risk for gout. In males, uric acid levels rise substantially at puberty. In about 5 - 8% of American men, levels exceed 7 mg/dL (indicating hyperuricemia). However, gout typically strikes after 20 - 40 years of persistent hyperuricemia, so men who develop it usually experience their first attack between the ages of 30 and 50.

Women. Before menopause, women have a significantly lower risk for gout than men, possibly because of the actions of estrogen. This female hormone appears to facilitate uric acid excretion by the kidneys. (Only about 15% of female gout cases occur before menopause.) After menopause the risk increases in women. At age 60 the incidence is equal in men and women, and after 80, gout occurs more often in women.

Family History

A family history of gout is present in close to 20% of patients with this condition. Three genetic locations have been associated with the body's uric acid handling and gout. Some people with a family history of gout have a defective protein (enzyme) that interferes with the way the body breaks down purines.

Obesity

Researchers report a clear link between body weight and uric acid levels. In one Japanese study, overweight people had two to more than three times the rate of hyperuricemia as those who maintained a healthy weight. Children who are obese may have a higher risk for gout in adulthood.

Medications

Thiazide diuretics are "water pills" used to control hypertension. The drugs are strongly linked to the development of gout. A large percentage of patients who develop gout at an older age report the use of diuretics.

Several other medications can increase uric acid levels and raise your risk for gout. These include:

• Aspirin -- low doses of aspirin reduce uric acid excretion and increase the chance for hyperuricemia. This may be a problem for older people who take baby aspirin (81 mg) to protect against heart disease.
• Niacin (used to treat cholesterol problems)
• Pyrazinamide (used to treat tuberculosis)

Alcohol

Drinking excessive amounts of alcohol can raise your risk of gout. Beer is the kind of alcohol most strongly linked with gout, followed by spirits. Moderate wine consumption does not appear to increase the risk of developing gout.

Alcohol use is highly associated with gout in younger adults. Binge drinking particularly increases uric acid levels. Alcohol appears to play less of a role among elderly patients, especially among women with gout.

Alcohol increases uric acid levels in the following three ways:

• Providing an additional dietary source of purines (the compounds from which uric acid is formed)
• Intensifying the body's production of uric acid
• Interfering with the kidneys' ability to excrete uric acid

Lead Exposure

Chronic occupational exposure to lead is associated with build-up of uric acid and a high incidence of gout.

Organ Transplants

Kidney transplantation poses a high risk for renal insufficiency and gout. In addition, other transplantation procedures, such as heart and liver, increase the risk of gout. The procedure itself poses a risk of gout, as does the medication (cyclosporine) used to prevent rejection of the transplanted organ. Cyclosporine also interacts with indomethacin, a common gout treatment.

The kidneys are responsible for removing waste from the body, regulating electrolyte balance and blood pressure, and stimulating red blood cell production.

Other Illnesses

Treatment of several other conditions can cause significant elevations of uric acid in the blood, and therefore a gout attack. These conditions include:

• Leukemia
• Lymphoma
• Psoriasis