Coffee is one of the most widely consumed beverages around the world. Dietary habits, specifically, coffee consumption has long been a suspected cause of hypertension. However, previous findings on coffee consumption and its association with the incidence of hypertension are not homogeneous and still inconsistent.
To examine the association of habitual coffee consumption with the risk of developing hypertension in a middle-aged Brazilian cohort.
Data were from the multicenter prospective cohort “Brazilian Longitudinal Study for Adult Health – ELSA-Brasil”. The cohort comprises 15,105 civil servants, aged 35-74 years at baseline, who were sampled from universities located in six Brazilian cities. For the present study, we analyzed data from 8780 participants initially free of hypertension during a mean follow-up of 3.9 years. The consumption of coffee was obtained at baseline using a previously validated semi-quantitative food frequency questionnaire (FFQ). Subsequently coffee intake was categorized into four categories (cups/day): never/almost never, ≤1, 1-3, and >3. Hypertension status was defined as a systolic blood pressure ≥140 mmHg or a diastolic blood pressure ≥90 mmHg, use of antihypertensive drug treatment, or both. Poisson regression model with a robust variance was performed to estimate relative risk (RR) and confidence interval (95% CI) for hypertension according to baseline coffee consumption. The effect of interaction between coffee consumption and smoking status was assessed.
Most participants (90%) drank coffee, and the median total coffee intake was 150 mL/day. A total of 1285 participants developed hypertension. Compared to participants who never or almost never drink coffee, the risk of hypertension was lower for individuals consuming 1-3 cups/day (RR 0.82, 95% CI: 0.68-0.97) (P for interaction=0.018). After stratification by smoking status the analysis revealed a decreased risk of hypertension in never smokers drinking 1-3 cups of coffee per day (RR 0.79, 95% CI: 0.64-0.98), whereas the hypertension risk among former and current smokers was not associated with coffee consumption significantly. Moreover, upper category of coffee drinking (>3 cups/day) the association was not significant for risk of hypertension.
The association between coffee consumption and incidence of hypertension was related to smoking status. The beneficial effect of moderate coffee intake (1-3 cups/day) on risk of hypertension was observed only in never smokers.