BASE-LINE SODIUM-LITHIUM COUNTERTRANSPORT AND 6-YEAR INCIDENCE OF HYPERTENSION - THE GUBBIO POPULATION STUDY

Background Sodium-lithium countertransport (Na-Li CT) activity is high in persons with hypertension. This study investigated whether high Na -Li CT relates to development of hypertension. Methods and Results At the baseline visit of the Gubbio Population Study, 4210 people of the 5376 surveyed were 18 to 74 years old; of these, 1599 were hypertensiv e (systolic pressure greater than or equal to 140 mm Hg, or diastolic pressure greater than or equal to 90 mm Hg, or on antihypertensive dru g therapy). Of the 2611 nonhypertensives, 302 did not have Na-Li CT me asured and 580 did not participate in 6-year follow-up. This analysis, therefore, deals with data collected on 1729 men 18 to 74 years old a nd women 18 to 74 years old who at baseline were nonhypertensive and h ad Na-Li CT measurement. Compared with individuals who were nonhyperte nsive at baseline and follow-up, individuals with incident hypertensio n at follow-up (systolic pressure greater than or equal to 140 mm Hg, or diastolic pressure greater than or equal to 90 mm Hg, or on antihyp ertensive drug therapy) had higher baseline values of Na-Li CT, blood pressure, age, body mass index, plasma cholesterol, and alcohol intake (P<.05). Baseline Na-Li CT was positively associated (P<.05) with dev elopment of hypertension in quartile analysis, with highest incidence of hypertension among men and women with Na-Li CT in the highest quart ile (for men, greater than or equal to 376 and for women, greater than or equal to 311 mu mol Li . L red blood cells(-1) . h(-1)). In univar iate logistic regression, incidence of hypertension was related to bas eline value of Na-Li CT, blood pressure, age, body mass index, plasma cholesterol, and alcohol intake (P<.05). In multiple logistic regressi on analysis, individuals with baseline Na-Li CT higher by 127 mu mol ( pooled SD for men and women) had 1.23 times greater risk of incident h ypertension with control for sex and baseline age, body mass index, sy stolic pressure, and other confounders (P<.001). Conclusions Na-Li CT is a predictor of hypertension risk in adults.