1From the Department of Epidemiology, Michigan State University, East Lansing, MI (ZZ); Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA (GH); the Center for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (BC); the Department of Internal Medicine, Johns Hopkins Medical Institutions, Baltimore, MD (LA); and the Program of Epidemiology, School of Public Health, Louisiana State University Health Science Center, New Orleans, LA (CL).
↵2 Supported by Louisiana State University Health Science Center, School of Public Health (to ZZ and LC); Pennington Biomedical Research Center (to GH); and the Center for Human Nutrition, Johns Hopkins Bloomberg School of Public Health (LA and BC).
↵3 Address correspondence to L Chen, Program of Epidemiology, School of Public Health, Louisiana State University Health Science Center, 1615 Poydras Street, Suite 1400, New Orleans, LA 70112. E-mail: email@example.com.
Background: In 2 meta-analyses of randomized controlled trials, increased coffee intake was associated with slightly higher blood pressure. However, these trials were short in duration (<85 d).
Objective: We conducted a systematic review and meta-analyses of long-term prospective studies that examined the association of habitual coffee consumption with risk of hypertension.
Design: We searched electronic databases (MEDLINE, EMBASE, Agricola, and Cochrane Library) through August 2009 with the use of a standardized protocol. Eligible studies were prospective cohort trials that examined the association of coffee consumption with incident hypertension or blood pressure.
Results: From 6 prospective cohort studies, a total of 172,567 participants and 37,135 incident hypertension cases were included. Mean follow-up ranged from 6.4 to 33.0 y. Compared with the lowest consumption [<1 cup (≈237 mL)/d], the pooled relative risks (RRs) for hypertension were 1.09 (95% CI: 1.01, 1.18) for the next higher category (1–3 cups/d), 1.07 (95% CI: 0.96, 1.20) for the second highest category (3–5 cups/d), and 1.08 (95% CI: 0.96, 1.21) for the highest category (>5 cups/d). A dose-response meta-analysis showed an inverse “J-shaped” curve (P for quadratic term < 0.001) with hypertension risk increasing up to 3 cups/d (RR for comparison of 3 with 0 cups/d: 1.07; 95% CI: 0.97, 1.20) and decreasing with higher intakes (RR for comparison of 6 with 0 cups/d: 0.99; 95% CI: 0.89, 1.10).
Conclusion: The results suggest that habitual coffee consumption of >3 cups/d was not associated with an increased risk of hypertension compared with <1 cup/d; however, a slightly elevated risk appeared to be associated with light-to-moderate consumption of 1 to 3 cups/d.