title: Altered renal sodium handling and risk of incident hypertension: Results of the Olivetti Heart Study.
abstract: Renal tubular sodium (Na) handling plays a key role in blood pressure (BP) regulation. Several cross-sectional studies reported a positive association between higher proximal tubule fractional reabsorption of Na and BP, but no prospective investigation has been reported of this possible association. Hence, the purpose of this study was to estimate the predictive role of renal Na handling on the risk of incident hypertension and the changes in BP occurring in the 8-year follow-up observation of a sample of initially normotensive men (The Olivetti Heart Study). The study included 294 untreated normotensive non-diabetic men with normal renal function examined twice (1994-95 and 2002-04). Renal tubular Na handling was estimated by exogenous lithium clearance. Fractional reabsorption of Na in proximal and distal tubules was calculated and included in the analysis. At baseline, there was no association between BP and either proximal or distal fractional reabsorption of Na. At the end of the 8-year follow-up, direct associations were observed between baseline proximal (but not distal) Na fractional reabsorption and the changes occurred in systolic and diastolic BP over time (+2.79 and +1.53 mmHg, respectively, per 1SD difference in proximal Na-FR; p<0.01). Also multivariable analysis showed a direct association between baseline proximal Na fractional reabsorption and risk of incident hypertension, independently of potential confounders (OR: 1.34, 95%CI:1.06-1.70). The results of this prospective investigation strongly suggest a causal relationship between an enhanced rate of Na reabsorption in the proximal tubule and the risk of incident hypertension in initially normotensive men.
authors.affiliation: Department of Clinical Medicine and Surgery, ESH Excellence Center of Hypertension, "Federico II" University of Naples Medical School, Naples, Italy.
authors.forename: Lanfranco
authors.initials: L
authors.lastname: D'Elia
authors.affiliation: University of Warwick, Division of Health Sciences, WHO Collaborating Centre for Nutrition, Coventry, United Kingdom.
authors.forename: Francesco P
authors.initials: FP
authors.lastname: Cappuccio
authors.affiliation: Department of Clinical Medicine and Surgery, ESH Excellence Center of Hypertension, "Federico II" University of Naples Medical School, Naples, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Iacone
authors.affiliation: Department of Clinical Medicine and Surgery, ESH Excellence Center of Hypertension, "Federico II" University of Naples Medical School, Naples, Italy.
authors.forename: Ornella
authors.initials: O
authors.lastname: Russo
authors.affiliation: Department of Clinical Medicine and Surgery, ESH Excellence Center of Hypertension, "Federico II" University of Naples Medical School, Naples, Italy.
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Galletti
authors.affiliation: Department of Clinical Medicine and Surgery, ESH Excellence Center of Hypertension, "Federico II" University of Naples Medical School, Naples, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Strazzullo
mesh_terms: D000328:Adult; D001692:Biological Transport; D001794:Blood Pressure; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000378:metabolism* / Q000503:physiopathology; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods / Q000706:statistics & numerical data*; D012307:Risk Factors; D012964:Sodium / Q000378:metabolism*; D013997:Time Factors
chemical_list: D012964:Sodium