Kidney stones are on the rise, according to a study in Mayo Clinic Proceedings, which looked at the medical records of a sample of first-time stone formers in a county in Minnesota.
Between 1984 and 2012, the incidence of confirmed stones (as seen on imaging tests or after voiding) increased four-fold in women and doubled in men, with the largest increase seen in women ages 18 to 39.
The study had some limitations, however: It focused mostly on white people (who are at higher risk for kidney stones than other racial groups) and was limited to one part of the country (kidney stone incidence rates may vary regionally).
Part of the uptick in kidney stones may be due to greater detection using imaging technologies, particularly CT scans, but the researchers suggested additional possible reasons, notably an increase in diets that are high in salt, animal protein, and sugar, which may boost urinary calcium excretion and thus contribute to calcium stones. In addition, more people have insulin resistance (which comes with rising obesity), which similarly increases calcium excretion.
A previous study in Environmental Health Perspectives in 2014 ventured yet another possible reason for the increase in kidney stones: Hotter days due to climate change increase dehydration, which increases the concentration of minerals in urine that promote kidney stones.
Drinking more water decreases the risk of kidney stone. So, too, might reducing sodium, animal protein, and sugar.
A version of this article first appeared in the UC Berkeley Wellness Letter.
Also see Kidney Stones: 7 Smart Steps.