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Kidney Stones: Overview and Risk Factors

Kidney stones, or nephrolithiasis, are quite common in the United States and other Western societies; nearly 10 percent of Americans will develop a kidney stone during their lifetime.

Stones form when minerals, such as calcium, or other molecules, such as uric acid, are present in the urine at abnormally high levels. These substances form crystals that gradually increase in size and can become stuck within the kidney or urinary tract. Calcium–containing stones are the most common, making up more than 75 percent of cases.

Symptoms include severe flank pain, which may also be felt in the lower abdomen, groin, or testicles; painful urination; bloody urine; and nausea or vomiting.

Risk Factors

  • Male gender: Males are three times more likely to develop stones than females.
  • History of kidney stones: Individuals who have developed a kidney stone have an 80 percent chance of recurrence within 10 years. Individuals with a family history of kidney stones have a two to three times higher risk.
  • Geography: Individuals in areas of elevated temperatures and high humidity appear to have an increased risk.
  • Nationality: Individuals in developed countries have a much higher risk compared with individuals in developing countries. This is presumed to be due to dietary factors, specifically the absence of a Western–style, meat–based diet.
  • Obesity: Compared with normal–weight persons, obese men have a 33 percent greater risk for stone formation, while obese women have a 200 percent greater risk.
  • Diet: Diet plays an important role, as described below in Nutritional Considerations.
  • Chronic urinary tract infections
  • Dehydration (e.g., diarrhea)
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Kidney Stones: Diagnosis and Treatment >>