Low to Moderate Coffee Intake May Increase Risk for Antihypertensive Drug Treatment

August 31, 2007 — Coffee intake increases the risk for antihypertensive drug treatment for low to moderate coffee drinkers, according to the results of a prospective study published in the August issue of American Journal of Clinical Nutrition.
"Only 2 prospective studies have previously investigated the association between coffee consumption and incident hypertension, and the findings are equivocal," write Gang Hu, from the University of Helsinki in Finland, and colleagues. "Compared with many other populations, men and women in Finland have a high prevalence of hypertension. Therefore, research into the potential health effects of coffee in this population is of particular interest."
Using questionnaires, the investigators determined daily coffee consumption in 24,710 Finnish subjects and observed them prospectively for a mean period of 13.2 years. At baseline, subjects were aged 25 to 64 years and had no history of antihypertensive drug treatment, coronary heart disease, or stroke. Multivariate adjustments were made for age, sex, study year, education, leisure-time physical activity, smoking status, body mass index (BMI), high total cholesterol level, history of diabetes, and consumption of alcohol, tea, fruit, vegetable, sausage, and bread.
During follow-up, 2505 subjects began antihypertensive drug treatment. Adjusted hazard ratios (HRs) for antihypertensive drug treatment associated with the amount of coffee consumed daily (0 - 1, 2 - 3, 4 - 5, 6 - 7, or ≥ 8 cups) were 1.00, 1.29 (95% confidence interval [CI], 1.09 - 1.54), 1.26 (95% CI, 1.06 - 1.49), 1.24 (95% CI, 1.04 - 1.48), and 1.14 (95% CI, 0.94 - 1.37; P for trend = .024), respectively. After additional adjustment for baseline systolic blood pressure, this trend became marginally significant (P for trend = .077).
"The results indicate that coffee drinking seems to increase the risk of antihypertensive drug treatment, and this risk was higher in subjects with low-to-moderate coffee intakes; however, there was no significantly increased trend in drinkers of ~ 1 cup (100 mL)/d or ≥ 8 cups/d," the authors write. "The increased risk showed no dose-response relation, but a threshold was observed between those who drank > 1 cup/d and those who drank only 0-1 cups/d."
Study limitations were self-reported data on coffee intake only at baseline, potential bias from a possible change in coffee consumption during follow-up, lack of data on consumption of cola beverage and chocolate, possible residual confounding from measurement error and unmeasured factors, and the use of only drug-treated hypertension as an endpoint.
"On the basis of this large study in a population with the [greatest] per capita coffee consumption in the world, it is obvious that coffee drinking may not be a major risk factor for hypertension," the authors conclude. "Even though the risk of hypertension associated with coffee consumption was relatively small, it may have some public health importance because coffee is the most consumed drink, other than water, and hypertension is a major health problem in the world. On the other hand, because coffee consumption seems to reduce the risk of type 2 diabetes, the relation between coffee consumption and cardiovascular disease risk is complicated, and further studies are needed."
The Finnish Academy and the Finnish Foundation for Cardiovascular Research supported this study. The authors have disclosed no relevant financial relationships.
Am J Clin Nutr. 2007;86:457-464.