Urolithiasis—a study of drinking water hardness and genetic factors

A study of the prevalence of kidney stone formers and the relationship of genetic factors and drinking-water composition to prevalence was completed in six districts in Newfoundland where 82% of stone formers have calcium-containing stones. One thousand one hundred and twelve adult (age ≥ 25) informants were interviewed in a random sample of households. The mean prevalence of stone formers among males was 15.5% (range 2.3–28.6%) and, among females, 8.3% (range 3.7–11.7%). There was no detectable association between district prevalence (male or female) and the mean district drinking-water hardness nor its content of calcium, magnesium, silica, zinc, manganese, iron or copper. There was a significant excess of affected parents of female stone formers compared to affected parents of female non-formers (p < 0.001) while the differences were not significant between parents of male stone formers and non-formers (p > 0.1). There was a higher, though not statistically significant, prevalence among the parents of female stone formers as compared to parents of male stone formers (0.2 > p > 0.1). The family history data in these first-degree relatives of affected and non-affected individuals is consistent with a polygenic mode of inheritance.