title: Red blood cell sodium-lithium countertransport and risk of future hypertension: the Olivetti Prospective Heart Study.
abstract: An elevated red blood cell (RBC) sodium-lithium countertransport (Na-Li CT) is associated with high blood pressure (BP) in cross-sectional investigations; however, its value as a predictor of future hypertension, and thus of cardiovascular risk, has not been defined. The present study evaluated the association between Na-Li CT and risk of future hypertension in a sample of 106 untreated normotensive middle-aged men participating in the Olivetti Prospective Heart Study in southern Italy. BP, anthropometric and metabolic variables, and RBC Na-Li CT were measured at baseline in 1987 and at a follow-up visit in 1994 through 1995. Na-Li CT was stable over time (r=0.85) and was significantly associated to systolic BP in both visits. Of the 106 initially normotensive participants, 14 were found to be hypertensive at the 8-year follow-up examination. Eleven of these 14 hypertensives were in the highest tertile of systolic BP at baseline, and 9 of 11 also had an elevated baseline Na-Li CT. In multiple logistic regression analysis, baseline BP, Na-Li CT, and age were all significant predictors of the risk of future hypertension. Individuals with baseline systolic BP in the highest tertile had a 60% risk of developing hypertension if their Na-Li CT was also high, whereas their risk was only 5% if Na-Li CT was in the two lowest tertiles (P=0.003). RBC Na-Li CT was a valuable predictor of subsequent hypertension in middle-aged men with a high-normal BP level for their age.
authors.affiliation: Department of Clinical and Experimental Medicine, Federico II University of Naples Medical School, Italy. strazzul@unina.it
authors.forename: P
authors.initials: P
authors.lastname: Strazzullo
authors.forename: A
authors.initials: A
authors.lastname: Siani
authors.forename: F P
authors.initials: FP
authors.lastname: Cappuccio
authors.forename: M
authors.initials: M
authors.lastname: Trevisan
authors.forename: E
authors.initials: E
authors.lastname: Ragone
authors.forename: L
authors.initials: L
authors.lastname: Russo
authors.forename: R
authors.initials: R
authors.lastname: Iacone
authors.forename: E
authors.initials: E
authors.lastname: Farinaro
mesh_terms: D000367:Age Factors; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure; D002784:Cholesterol / Q000097:blood; D004912:Erythrocytes / Q000378:metabolism*; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000209:etiology*; D017136:Ion Transport; D008094:Lithium / Q000097:blood*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D012964:Sodium / Q000097:blood*; D013997:Time Factors; D014280:Triglycerides / Q000097:blood; D014527:Uric Acid / Q000097:blood
chemical_list: D001786:Blood Glucose; D014280:Triglycerides; D014527:Uric Acid; D002784:Cholesterol; D008094:Lithium; D012964:Sodium