INTERACTIVE EFFECT OF CIGARETTES AND COFFEE ON DAYTIME SYSTOLIC BLOOD-PRESSURE IN PATIENTS WITH MILD ESSENTIAL-HYPERTENSION

Objective: To test the hypothesis that moderate smoking (fewer than 20 cigarettes/day) and coffee consumption have an interactive effect on ambulatory blood pressure. Design: A case-control study. Setting: Patients in the multicentre Hypertension Ambulatory Venetia Study, northeastern Italy. Subjects: Six hundred and forty-three men and 244 women with borderline-to-mild hypertension that had never been treated, subdivided according to their smoking status (non-smokers versus smokers) and their habitual consumption of coffee (0, 1-3, or 4+ cups/day). Main outcome measures: Office blood pressure, ambulatory blood pressure, urinary adrenaline and noradrenaline levels according to smoking status, coffee consumption and their interaction. Results: In the men, daytime systolic blood pressure (SEP) was significantly higher in the smokers than in the non-smokers and in the coffee drinkers than in the others. Moreover, two-way analysis of covariance revealed a significant interaction between smoking status and coffee consumption: the daytime SEP in smokers who drank 4+ cups/day of coffee was 6.0 mmHg higher than that of non-smokers who abstained from coffee. Conversely, office blood pressure was lower in the smokers than in the non-smokers and was similar in the coffee drinkers and the others. Coffee consumption had a significant effect on urinary adrenaline. Similar results were obtained in the women. Conclusions: In contrast with what is shown by office blood pressure measurement, moderate smokers and coffee drinkers with mild hypertension have significantly higher daytime SEP levels than non-smokers and those who do not drink coffee. Cigarettes and coffee have an interactive effect on daytime SEP in young patients with mild essential hypertension.