Kidney stones and risk of hypertension.

Cross-sectional studies have suggested a positive association between nephrolithiasis and blood pressure. However, this finding remains controversial due to methodologic problems and limited data. We conducted a prospective study of the relation between nephrolithiasis and the risk of hypertension in a cohort of 39,441 men, 40 to 75 years of age, who had no history of hypertension at baseline in 1986 and who were not taking thiazides or any other form of anti-hypertensive medication. Information was obtained by biennial mailed questionnaire. A history of nephrolithiasis was reported by 2,834 (7.2%) in 1986. During six years of follow-up, 4,125 (10.5%) reported a new diagnosis of hypertension. The proportion of men with a medical examination during follow-up was 81.8% in men with a history of nephrolithiasis and 79.7% in those without. After adjusting for age, the odds of incident hypertension in men with a history of nephrolithiasis compared to those without was 1.30 (95% CI: 1.16 - 1.45). After further adjustment for body mass index and the intake of calcium, sodium, potassium and magnesium, the odds ratio was 1.26 (95% CI: 1.12 - 1.41). Also, among men without hypertension at baseline or during the follow-up period, we observed a positive trend between history of nephrolithiasis and systolic blood pressure (p=0.06). These data support the hypothesis that nephrolithiasis is associated with an increased risk of hypertension.