Risk Factors

About 20 million Americans harbor gallstones. Only 1% to 3% of the population, however, complains of symptoms during the course of a year, and less than have of these people will experience recurrent symptoms.

Risk Factors in Women

Women are much more likely than men to develop gallstones. They occur in nearly 25% of women in the US by age 60 and up to 50% by age 75. (Again, in most cases they are asymptomatic.) In general, women are probably at increased risk because estrogen stimulates the liver to remove more cholesterol from blood and divert it into the bile.

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Pregnancy. Pregnancy increases the risk for gallstones, and pregnant women with stones are more likely to have symptoms than nonpregnant women. Surgery should be delayed until after delivery in most cases. In fact, gallstones may disappear after delivery. If surgery is needed laparoscopy is the safer approach.

Hormone Replacement Therapy. Several large studies have shown that use of hormone replacement therapy (HRT) doubles or triples the risk for gallstones or gallbladder surgery. A 2005 Journal of the American Medical Association study found that while all types of HRT raise the risks, estrogen alone has higher risks than combined estrogen and progesterone therapy. Estrogen has an effect on the liver and raises triglycerides, a fatty acid that increases the risk for cholesterol stones. Recent studies on HRT reporting negative effects on the heart and increased risks for breast cancer are also making this treatment a less attractive option for most postmenopausal women.

Risk Factors in Men