A prospective study of hypertension and the incidence of kidney stones in men

Objective To examine whether hypertension predicts the incidence of kidney stone disease. Design Prospective cohort study (the Olivetti Prospective Heart Study). Setting The Olivetti factory in Southern Italy. Subjects Five hundred and three male workers, aged 21 - 68 years, with no e vidence of kidney stone disease at baseline. Follow-up 8 years. Main outcome measures Anthropometry, blood pressure, biochemistry and histo ry of kidney stone disease were evaluated at the baseline examination in 19 87. Occurrence of kidney stone disease was evaluated again in 1994-1995. Hy pertension was defined as systolic blood pressure greater than or equal to 160 or diastolic blood pressure, greater than or equal to 95 mmHg or both, or being on drug therapy for hypertension. Occurrence of kidney stone disea se was defined as radiological or echographic evidence of calculi or docume nted passage of one or more stones. Results At baseline, 114/503 men (22.7%) had hypertension and 32 were on dr ug treatment After 8 years, 52 (10.3%) incident cases of kidney stone disea se were detected. The majority (n = 45) had a documented passage of one or more stones. The incidence of kidney stone disease was higher in hypertensi ve than in normotensive men (19/114 (16.7%) versus 33/389 (8.5%); P = 0.011 ). Hypertensive men had a greater risk of developing kidney stones than nor motensive ones (RR 1.96; 95% confidence interval 1.16-3.32). The risk was u naffected by the exclusion of treated hypertensives (2.01; 1.13-3.59) and a fter adjustment for age (1.89; 1.12-3.18), body weight (1.78; 1.05-3.00) or height (2.00; 1.19-3.38). Conclusions Hypertension in middle-aged men is a significant predictor of k idney stone disease rather than a consequence of renal damage caused by the kidney stones. J Hypertens 1999, 17:1017-1022 (C) Lippincott Williams & Wi lkins.