Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Incidence of hypertension in individuals with different blood pressure salt-sensitivity: results of a 15-year follow-up study Gianvincenzo Barba a , Ferruccio Galletti b , Francesco P. Cappuccio c , Alfonso Siani a , Antonella Venezia b , Marco Versiero b , Elisabetta Della Valle d , Paolo Sorrentino b , Giovanni Tarantino b , Eduardo Farinaro d and Pasquale Strazzullo b Objective To evaluate the incidence of hypertension and the rate of decline in renal function in a sample of 47 Olivetti Heart Study (OHS) participants whose blood pressure (BP) salt-sensitivity and renal tubular sodium handling had been assessed in 1987–88. Methods During the 2002–04 OHS follow-up examination, medical history, physical examination and blood and urine sampling were performed in 36 of the 47 participants to the baseline study (age 60 W 6 years; average follow- up U 15.1 W 0.6 years). The renal length was measured in 23 participants by kidney ultrasonography. Based on the baseline salt-sensitivity evaluation, the subjects were classified into a lower salt-sensitivity (LSS, n U 20) and a higher salt-sensitivity group (HSS, n U 16). Results In comparison with the LSS group, HSS participants had a significantly higher incidence of hypertension (87.5 versus 50.0%, P U 0.02), a higher glomerular filtration rate (median, first to fourth quartile: 81.9, 72.3–95.2 versus 72.3, 59.9–81.2 ml/min; P U 0.03) and greater kidney length (median, first to fourth quartile: 68.2, 63.3–72.1 versus 61.9, 58.7–62.7 mm/m of height; P U 0.003). The incidence of hypertension remained significantly higher in HSS individuals after adjustment for age, intercurrent changes in body mass index and baseline blood pressure on low sodium diet (P U 0.04). Conclusion Our findings indicate that individuals with higher BP salt-sensitivity have a higher rate of incident hypertension and suggest an altered renal tubular sodium handling involving a trend to increased glomerular filtration rate and blood pressure over time as a possible mechanism. J Hypertens 25:1465–1471 Q 2007 Lippincott Williams & Wilkins. Journal of Hypertension 2007, 25:1465–1471 Keywords: blood pressure, glomerular filtration rate, prospective study, renal function, sodium dependent hypertension a Epidemiology and Population Genetics, Institute of Food Sciences, CNR, Avellino, b Department of Clinical and Experimental Medicine, ‘Federico II’ University of Naples, Naples, Italy, c Division of Clinical Sciences, Clinical Sciences Research Institute, Warwick Medical School, Coventry, UK and d Department of Preventive Medical Sciences, ‘Federico II’ University of Naples, Naples, Italy Correspondence to Gianvincenzo Barba, Epidemiology and Population Genetics, Institute of Food Science, National Research Council, Via Roma 52A/C, 83100 Avellino, Italy Tel: +39 0825299 353; fax: +39 0825299 423; e-mail: gbarba@isa.cnr.it Received 3 August 2006 Revised 4 February 2007 Accepted 15 February 2007 Introduction A heterogeneous blood pressure (BP) response to changes in dietary sodium chloride intake, a phenom- enon generally referred to as BP salt-sensitivity, is observed in both hypertensive patients and normotensive individuals [1–3]. On the basis of the feature character- istics of well described forms of monogenic hypertension [4–6], it is conceivable that a different ability of the kidney to excrete sodium and water is involved in this phenomenon [7]. We have previously reported on BP, renal function and tubular sodium handling in a sample of healthy normo- tensive male volunteers drawn from a middle-aged male working population in 1987–88 [3]. Our results showed that those with higher salt-sensitivity, estimated by their BP response to low salt diet, had increased BP, greater proximal tubular sodium reabsorption and higher glomer- ular filtration rate (GFR) when on habitual high sodium diet compared to those with a lower degree of salt- sensitivity. These alterations were no longer apparent when the subjects were placed on a low sodium diet (40 mmol Na/day for 3 days). We speculated that the trend to greater tubular sodium reabsorption detected in the more salt-sensitive subjects elicited humoral adaptive responses to overcome the difficulty in sodium excretion at the cost of an increase in BP and GFR. Other studies have reported increased GFR and/or intraglomerular pressure in salt-sensitive hypertension [8–13]. In turn, hyperfiltration could heighten suscepti- bility to renal function deterioration and actually it has been found to be associated with early organ damage in hypertensive patients [14]. Original article 1465 0263-6352 ß 2007 Lippincott Williams & Wilkins