Our findings should be considered in the context ofimportant limitations. The rapid increase in radiologicimaging in the United States could translate into anincreased diagnosis of asymptomatic kidney stones. Toexamine this possibility, we analyzed self-report of kidneystone passage as a secondary outcome. While the prevalenceof stone passage wasslightly lower than self-report ofa history of kidney stones, these estimates still represent amarked increase in stone disease. The prevalence of stonedisease increases with age; therefore, the aging of the USpopulation would be expected to contribute to an overallincrease in the prevalence of stone disease absent any otherinfluences. However, population adjustment of our estimatessuggested that changes in prevalence because of theaging of the population only partially explained theobserved changes in prevalence.