Background. The longitudinal relationship between coffee use and hypertension is not well known.

Aim. We did a prospective study to investigate if there is a temporal relationship between coffee consumption and development of sustained hypertension.

Method. We assessed 1107 white subjects with elevated blood pressure who were followed up for 6.4 years. Coffee intake and other life-style factors were ascertained from regularly administered questionnaires. Incident physician-diagnosed hypertension was the outcome measure.

Results. During the follow-up, 561 subjects developed sustained hypertension, whereas 546 subjects did not meet the criteria for treatment. Coffee drinkers developed sustained hypertension more frequently than abstainers (53.1% versus 43.9%, P = 0.007). The incidence of hypertension did not differ between moderate and heavy coffee drinkers. Kaplan-Meier analysis confirmed that sustained hypertension was developed more frequently by coffee drinkers compared with nondrinkers (P<0.001). The adjusted relative risk of hypertension was greater in both categories of coffee drinking than in abstainers (hazard ratio, 95% confidence limit (CL) = 1.24, 1.06-1.44). The risk of hypertension associated with coffee drinking increased gradually with increasing level of alcohol use (adjusted P for interaction = 0.005).

Conclusions. In subjects screened for stage 1 hypertension a nonlinear association was found between coffee consumption and development of sustained hypertension.