| Background The mortality and morbidity of coronary heart disease (CHD) tend to increase every year. Coffee is one of the most widely consumed beverages worldwide. The active compounds it contains have both positive and negative effects on cardiovascular system. Caffeine can increase blood pressure, serum cholesterol and homocysteine, while chlorogenic acid and other antioxidants can eliminate free radicals. The association between coffee consumption and risk of coronary heart disease remains controversial despite many epidemiological studies.Methods We searched prospective cohort studies in PubMed and Cochrane library (December2012). Quantitative meta-analyses were performed to assess the risk of habitual consumption of coffee and coronary heart disease. Two reviewers extracted the basic characteristics of participants, levels of coffee consumption and relative risks (RR) and95%confidence interval (CI).Results Compared to the reference category, the RRs (95%CI) of CHD were1.03(95%CI:0.87.1.22, P=0.74),1.05(95%CI:0.89,1.25, P=0.56) and1.18(95%CI:0.87,1.60, P=0.30) folds in the low, moderate and high levels of coffee consumption groups respectively. Pooled RR is1.08(95%CI:0.96,1.22, P=0.20), and the pooled P value was1.08. In the sensitivity and subgroup analyses, we found the effects of coffee consumption on CHD were slightly different. In the Europe subgroup, the pooled RRs (95%CI) for low(n=11), moderate(n=11) and high(n=11) levels of coffee consumption were0.99(0.83,1.18),1.01(0.83,1.34) and1.01(0.84,1.89), and their P values were0.92,0.65and0.26respectively; while it’s1.03(0.87,1.22),1.01(0.82,1.25) and1.01(0.71,1.43) in the USA group (n=7), their P values are0.68,0.93and0.96respectively. The pooled RRs (95%CI) for low(n=14), moderate(n=14) and high(n=14) levels of coffee consumption in men subgroup were0.95(0.81,1.12),1.00(0.85,1.22) and1.07(0.83,1.38), and their P values were0.54,0.86and0.62respectively. The RRs of women subgroup(n=8) were1.07(0.76,1.50),1.01(0.88,1.16),1.10(0.88,1.47) respectively, and their P value were0.72,0.92and0.52. The pooled RRs (95%CI) of the5-10years follow-up period werel.07(0.88,1.30),1.04(0.84,1.28) and1.21(0.83,1.76) for low(n=4), moderate(n=4) and high(n=4) category respectively, their P values were0.50,0.72and0.33. For the more than10-year group(n=14), the pooled RRs (95%CI) were0.88(0.73,1.05),1.16(0.97,1.40) and1.13(0.73,1.76) respectively, and their P values were0.15,0.11and0.59. No significant difference was found in all above subgroups.Conclusion Habitual consumption of coffee neither increased nor reduced the risk of coronary heart disease. The result was not affected by levels of coffee consumption, age, district, gender or follow-up period. |
