AMBULATORY 24-H BLOOD-PRESSURE MONITORING IN HEALTHY, MIDDLE-AGED SMOKELESS TOBACCO USERS, SMOKERS, AND NONTOBACCO USERS

Ambulatory 24-h blood pressure monitoring was conducted in 135 healthy , normotensive, middle-aged (35 to 60 years) men, with no antihyperten sive medication, to study the influence of habitual smokeless tobacco use (n = 47) and smoking (n = 29) on diurnal blood pressure and heart rate. Comparisons were made with nonusers of tobacco (n = 59). Adjustm ents were made for differences in age, body mass index, waist-hip rati o, physical fitness, and alcohol intake. Daytime ambulatory heart rate s were significantly (P < .05) elevated in both smokeless tobacco user s and smokers compared with nonusers (69 +/- 14 and 74 +/- 13 beats/mi n, respectively, versus 63 +/- 12 beats/min). In subjects greater than or equal to 45 years old, ambulatory daytime diastolic blood pressure s were significantly elevated, on average by 5 mm Hg, in both smokeles s tobacco users and smokers (P < .001) compared with nonusers. Clinica l measurements of heart rate and systolic blood pressure in smokers we re significantly lower compared with the ambulatory mean values. Night time measurements showed only minor differences between the tobacco ha bit groups. The higher heart rates and blood pressures noted during th e daytime in smokers and smokeless tobacco users were most likely due to the effects of nicotine. A strong positive relationship was found b etween cotinine (major nicotine metabolite) and blood pressure in smok eless tobacco users (systolic blood pressure, r = 0.48, P < .001; dias tolic blood pressure, r = 0.41, P = .005), whereas an inverse relation ship was found in smokers (systolic blood pressure, r = -0.12, P = .47 ; diastolic blood pressure, r = -0.03, P = .84), indicating additional and more complex influences on vascular tone in smokers than the infl uence of nicotine in smokeless tobacco users. Am J Hypertens 1998; 11: 1153-1163 (C) 1998 American Journal of Hypertension, Ltd.