The peak onset age is between 20 and 30. The problem often runs in families. Kidney stones commonly cause illness but uncommonly cause kidney failure or death. Abnormal urine from bodily chemical processes or environmental causes make salts exceed their solubility in urine. There are 4 major groups.
Some people absorb excess calcium or leech bone calcium.
Calcium stone formation is usually inherited and unexplained. Too much Vitamin C can contribute. Low urinary citric acid from too much meat, bowel disease, acid retention, or excessive exercise can help precipitate stones. Causative factors are found in a third. On the average, stone formers produce a new stone every two to three years.