Association between habitual coffee consumption and blood pressure levels

Abstract

The relationship between habitual coffee consumption and blood pressure was investigated in 9601 subjects (7506 men and 2095 women) who were office managers and employees, aged 18-65 years. Those who drank coffee had lower blood pressure levels than those who did not and the mean blood pressure levels decreased with increasing coffee consumption. In the men, blood pressure (systolic/diastolic) was highest in the non-coffee drinkers (130.0/83.0 mmHg) and lowest in those drinking >5 cups/day (126.0/81.3mmHg). Mean differences (± s.e.m.) corrected by analysis of covariance for age and body mass index (kg/m² ) were: systolic — 4.0 ± 0.7 mmHg,P < 0.0001; diastolic — 1.7 ± 0.5 mmHg, P < 0.001. In the women, blood pressure ranged from 121.1/77.4 mmHg in the non-coffee drinkers to 117.7/76.2 mmHg in those drinking >5 cups/day (mean ± s.e.m. systolic difference — 3.4 ± 1.4 mmHg, P < 0.05; diastolic —1.2 ± 0.9 mmHg, P > 0.05). These observations were confirmed after correction for physical activity, and cigarette and alcohol consumption (for age and body mass index). In the men, blood pressure ranged from 130.8/83.1 mmHg in non-coffee drinkers to 127.5/81.9 mmHg in those drinking > 5 cups/day, with the effect of classification by coffee consumption being very important (analysis of covariance: systolic F=12.17, 3degrees of freedom at numerator, P < 0.0001; diastolic F=3.56, 3 degrees of freedom at numerator, P=0.0135). In the women, blood pressure was 121.7/78.0 mmHg in non-coffee drinkers and 119.6/77.3 mmHg (P > 0.05) in those who drank>5 cups/day. The percentage of men with elevated blood pressure levels (> 140/90 mmHg) was 19.0 and 19.2% in the non-coffee drinkers and those drinking ≤ 3 cups/day, respectively, and 17.4 and 14.2% in those drinking ≤ 5 and>5 cups/day, respectively (x²= 10.4, 3 degrees of freedom,P =0.015). The percentage of women with high blood pressure was 7.9 and 9.2% in the non-coffee drinkers and in those drinking ≤ > 5 cups/day, respectively, and 3.8% in those drinking >5 cups/day (P > 0.05). Thus, our data indicate an inverse relationship between chronic coffee consumption and blood pressure levels, particularly in male subjects