Bureau of Epidemiology Pennsylvania Department of Health Harrisburg, PA 19017
The recent study by Jee et al. (1) was commendable, because it was a detailed meta-analysis of coffee consumption in clinical trials. However, the authors failed to include an important clinical trial on coffee intake and cholesterol in their meta-analysis. In 1995, Burr et al. (2
) published the results of a randomized crossover trial. They gave 5 cups of instant coffee daily for 6 weeks, versus no coffee for 6 weeks, at random to 261 healthy volunteers. They found a small but significant increase in serum cholesterol (0.12 mmol/liter, p = 0.003) and apolipoprotein B (1.69 mg/dl, p = 0.011) concentrations with consumption of 5 cups of instant coffee per day. Although previous small clinical trials did not demonstrate a positive association between instant coffee intake and cholesterol levels, Burr et al.'s clinical trial was the largest clinical trial on this issue to date (1
, 3
). Considering the crossover design, the sample size in the Burr et al. study should be larger than the sum of subjects in any other published clinical trials regarding the effects of instant or filtered coffee on serum cholesterol. From a statistical viewpoint, it is possible that the lack of a significant cholesterol-increasing effect of instant coffee in other studies might be attributable to the small sample sizes and the mild effect of instant coffee.
NOTES
Editor's note: In accordance with Journal policy, Jee and colleagues were asked whether they wished to respond to this letter, but they chose not to do so.
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