(2012) conducted a cohort study in which a large (over three million) group of patients had their renal activity monitored. The study ultimately came to focus on the subgroup who had undergone kidney stones: these were followed up with and examined, at a median follow-up period of eleven years, in Alberta, Canada. The goal was to examine patients who had experienced at least one episode of kidney stones and to see if that correlated with any other forms of kidney disease (up to and including end stage renal disease) later in life. The basic measure used for examining the patients on the follow-up visit was the level of serum creatinine, the most basic measure of kidney health that is available to physicians. Those patients who had double the expected serum creatinine level were judged to have chronic kidney disease. The most unexpected finding from the cohort study was the effect of kidney stones on young women. In this particular subgroup of the cohort -- of young women who had experienced at least one episode of kidney stones, and were followed up on by the study ten years after the original diagnosis -- the...

The overall findings held that the linkage of kidney stones to later end stage renal disease was greater for women than men overall, but also greater for the subgroup of patients diagnosed with kidney stones when under 50 years old, as opposed to those who received the kidney stone diagnosis when they were 50 or older. However, measured against the control, it was also worth noting that the risk of later adverse renal outcome was greater for all populations who had been diagnosed with kidney stones than it was for those who had never had kidney stones: the incidence calculated was 2.48 cases of end stage renal disease in one million with kidney stones, but only .52 per million without kidney stones.