Interactive effect of cigarettes and coffee on daytime systolic blood pressure in patients with mild essential hypertension. HARVEST Study Group (Italy). Hypertension Ambulatory Recording VEnetia STudy.

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 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 (SBP) 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 SBP 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 SBP levels than non-smokers and those who do not drink coffee. Cigarettes and coffee have an interactive effect on daytime SBP in young patients, with mild essential hypertension.