Past history of nephrolithiasis and incidence of hypertension in men: a reappraisal based on the results of the Olivetti Prospective Heart Study.

BACKGROUND: We have previously reported that in the Olivetti Prospective Heart Study cohort the incidence of nephrolithiasis was higher in hypertensive participants than in normotensive ones. As the time sequence and the mechanisms underlying the association between nephrolithiasis and hypertension remain controversial, we further tested the hypothesis that in a cohort of normotensive males a history of nephrolithiasis predicts the development of future hypertension. METHODS: The analysis was conducted in 381 male workers at Olivetti who were normotensive at the baseline examination and who were re-examined 8 years later. RESULTS: A past history of nephrolithiasis is associated with an increased risk of hypertension of 1.96 (95% CI=1.25-3.07) relative to subjects with a negative history, after adjusting for age. CONCLUSION: In this 8-year follow-up study, a history of nephrolithiasis resulted in an increased risk of developing hypertension in the future. As the reverse was also true, as previously reported, a clear-cut time sequence, as well as the mechanisms linking these two conditions, remain to be identified.