If researchers find a strong positive correlation between coffee consumption and heart attacks, they can conclude that there is an association between the two variables-that is, higher coffee consumption tends to occur alongside more heart attacks. However, this correlation alone does not prove that coffee consumption causes heart attacks. Correlation does not imply causation; other factors (confounders) might influence both coffee consumption and heart attack risk. In fact, extensive research shows a more nuanced relationship between coffee and cardiovascular health:
- Many studies indicate a J-shaped or nonlinear association, where moderate coffee consumption is linked to a decreased risk of some cardiovascular diseases, including heart failure and atrial fibrillation, while heavy coffee consumption might increase risk in certain groups
- Moderate coffee intake (about 3 to 5 cups per day) is often associated with the lowest cardiovascular disease risk, and heavy consumption is not consistently linked to elevated risk overall
- Some evidence suggests that the method of coffee preparation (filtered vs. unfiltered) and individual health conditions (e.g., severe hypertension) can influence how coffee affects cardiovascular risk
- Large population studies have found that regular coffee consumption is generally safe and may even reduce the risk of stroke and cardiovascular mortality in people without diagnosed heart disease
Therefore, given only a strong positive correlation, researchers should be cautious and avoid concluding that coffee causes heart attacks. They need to consider potential confounding variables, study design, and the broader body of evidence before making causal claims. Further research, including controlled trials and mechanistic studies, is necessary to clarify the nature of the relationship.
