Kidney stones are one of the most common disorders of the urinary tract. They are an ancient health problem. Evidence of kidney stones has been found in an Egyptian mummy estimated to be more than 7,000 years old.
At this time, studies suggest that kidney stones affect more than 5% of Americans, and the rate has increased since the 1970s.
Gender and Age
Men. Kidney stones are more common in men than women. The risk of kidney stones increases in men in their 40s and continues to rise until age 70. Caucasian men have a higher risk than other ethnic groups.
Women. The risk of kidney stones peaks in a woman's 50s. In younger women, stones are more likely to develop during the late stages of pregnancy. Pregnant women tend to have a higher calcium intake, but their kidneys do not handle the calcium as well as they did before pregnancy. Kidney stones are still rare during pregnancy, however, affecting only 1 in 1,500 pregnancies.
Risk Factors in Children. Stones in the urinary tract in children are usually due to genetic factors. Most of the time, the cause is too much calcium in the urine (hypercalciuria). Deformities in the urinary tract pose a significant risk for kidney stones in children. Babies born at a low birth weight who need to be fed intravenously are also at risk for stones.
Obesity and Weight Gain
Obesity and weight gain are both associated with an increased risk for kidney stones.
Higher BMIs and larger waist circumferences are both risk factors for kidney stones. Researchers think that there may be a link between fat tissue, insulin resistance, and urine composition. People with larger body sizes may excrete more calcium and uric acid into the urine, which increases the risk for kidney stone formation.
A family history of kidney stones increases one's risk for the condition. Researchers are looking into genetic markers or other factors that might predict the risk of kidney stones in relatives, although none has yet been clearly identified. A family history of gout may also make a person more vulnerable to developing stones.
Caucasians seem to have the highest incidence of kidney stones, followed by Mexican Americans. African-Americans have the lowest risk.
Review Date: 06/08/2010
Reviewed By: Reviewed by: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.