SUSTAINED CAFFEINE USE HAS NO PRESSER EFFECT IN THE ELDERLY

Background: Epidemiologic studies have suggested that caffeine consump tion is associated with hypertension in elderly individuals. Caffeine ingestion following a period of abstention does have an acute presser effect, although after several days of regular caffeine consumption th is response is much blunted or absent in the few studies conducted in young and middle-aged normotensive and hypertensive subjects. The aims of the present study were to examine the hemodynamic and neurohumoral responses to prolonged caffeine ingestion in elderly subjects over a wide blood pressure range. Methods: Eighteen fit ambulatory elderly su bjects (mean age, 78 years; range, 68 to 86 years; 11 men, 7 women) we re placed on a caffeine-free diet for 2 weeks prior to entering a doub le-blind, randomized, placebo-controlled crossover study for 4 weeks d uring which patients received either caffeine (250-mg capsules, twice a day) or matching placebo while continuing caffeine restriction. Clin ic and 24-hour ambulatory blood pressure were assessed at the end of e ach 4-week phase along with plasma caffeine, noradrenaline, adrenaline , and renin activity levels. Results: All 18 subjects, with clinic sys tolic and diastolic blood pressure ranging from 105 to 225 mm Hg and 5 4 to 108 mm Hg, respectively, completed the study with successful 24-h our ambulatory blood pressure recordings being obtained on both occasi ons in 12 subjects. There was no significant change in clinic or 24-ho ur ambulatory systolic blood pressure, diastolic blood pressure, or pu lse rate, or in any of the pressor mechanisms studied between the plac ebo and caffeine phases of the study. Furthermore no correlation was f ound between baseline blood pressure levels and the change in blood pr essure between placebo and caffeine phases. Conclusions: Chronic caffe ine ingestion in the amounts normally consumed daily has no significan t effect on clinic or 24-hour blood pressure levels in elderly subject s, irrespective of blood pressure status.