An interesting article regarding long-term coffee consumption and risk of cardiovascular disease was just published in Circulation. The meta-analysis, which included 35 cohort studies and 1,283,685 participants, suggests that long-term coffee consumption (3 to 5 cups per day) is cardio-protective and reduces your risk of developing cardiovascular disease.
Background — Considerable controversy exists regarding the association between coffee consumption and cardiovascular disease (CVD) risk. A meta-analysis was performed to assess the dose-response relationship of long-term coffee consumption with CVD risk. […]
Conclusions — A non-linear association between coffee consumption with CVD risk was observed in this meta-analysis. Moderate coffee consumption was inversely significantly associated with CVD risk, with the lowest CVD risk at 3 to 5 cups/d, and heavy coffee consumption was not associated with elevated CVD risk.
I found the following very interesting. If you smoke, you’re more likely to be a heavy coffee drinker. Smoking, of course, greatly increases your CVD risk and thus diminishes the protective effect seen for coffee drinkers. Remove the confounders (smokers) and the picture becomes much clearer. Smoking bad. Exercise and physical activity good. Three to five cups of coffee on top of that might just do you a little better.
However, since higher coffee consumption was generally associated with a less healthy lifestyle such as a higher prevalence of cigarette smoking, less physical activity, and a less healthy diet, the observed association between moderate coffee consumption and a lower CVD risk is unlikely to be explained by these confounders
Second, smoking is likely to be an important confounder for the association between coffee consumption and CVD risk, and could bias the relative risks upwards. Heavy coffee consumption was associated with higher risk of CVD in age-adjusted analyses, but this is likely due to confounding by smoking. After adjustment for smoking and other covariates, heavy coffee was consumption was not significantly associated with CVD and the inverse association between moderate consumption and CVD became stronger.
Three to five cups of coffee per day is just about exactly where I fall. A full PDF of the paper is available from Circulation.