Coffee Consumption and Risk of Stroke: A Dose-Response Meta-Analysis of Prospective Studies

Division of Nutritional Epidemiology, National Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-17177 Stockholm, Sweden.
American journal of epidemiology (Impact Factor: 5.23). 09/2011; 174(9):993-1001. DOI: 10.1093/aje/kwr226
Source: PubMed


Coffee consumption has been inconsistently associated with risk of stroke. The authors conducted a meta-analysis of prospective
studies to quantitatively assess the association between coffee consumption and stroke risk. Pertinent studies were identified
by searching PubMed and Embase from January 1966 through May 2011 and by reviewing the reference lists of retrieved articles.
Prospective studies in which investigators reported relative risks of stroke for 3 or more categories of coffee consumption
were eligible. Results from individual studies were pooled using a random-effects model. Eleven prospective studies, with
10,003 cases of stroke and 479,689 participants, met the inclusion criteria. There was some evidence of a nonlinear association
between coffee consumption and risk of stroke (P for nonlinearity = 0.005). Compared with no coffee consumption, the relative risks of stroke were 0.86 (95% confidence interval
(95% CI): 0.78, 0.94) for 2 cups of coffee per day, 0.83 (95% CI: 0.74, 0.92) for 3−4 cups/day, 0.87 (95% CI: 0.77, 0.97)
for 6 cups/day, and 0.93 (95% CI: 0.79, 1.08) for 8 cups/day. There was marginal between-study heterogeneity among study-specific
trends (I2 = 12% and I2 = 20% for the first and second spline transformations, respectively). Findings from this meta-analysis indicate that moderate
coffee consumption may be weakly inversely associated with risk of stroke.

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    • "Coffee is widely consumed in Western countries, and increasingly, Chinese are also consuming coffee. Coffee consumption has potential benefits, such as prevention of type 2 diabetes and cardiovascular disease [4] [5] [6] [7]; however , coffee consumption can also have harmful effects on human health. Generally, the average individual daily coffee consumption in China is equivalent to a moderate level in Western countries. "
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    • "Between-study heterogeneity was assessed by the I 2 statistic (I 2 < 30%, no between-study heterogeneity or marginal between-study heterogeneity; I 2 = 30–75%, mild heterogeneity; I 2 > 75%, notable heterogeneity) (Larsson and Orsini, 2011 "
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