Observational epidemiological studies of associations between coffee consumption and risk of cardiovascular disease were reviewed in the early 1990s (5, 6, 7). Greenland (6), for example, published a meta-analysis of 8 case control studies and 14 cohort studies and noted a fairly homogeneous increased risk in case control studies and a very heterogeneous and much smaller increased risk in cohort studies. It was concluded that “the evidence thus remains ambiguous regarding both the existence and size of a coffee effect”
A number of case control studies have been published since the early 1990s. An Italian case control study carried out within the framework of the GISSI-2 trial on therapy for heart attack survivors found that after adjustment for other risk factors coffee consumption may indicate an increase in the risk of heart attack (8). A second Italian case control study indicated that the consumption of decaffeinated coffee was significantly associated with risk of heart attack in women although this association was no longer significant after adjustment for diabetes, hypertension and hyperlipidaemia (9). However, a case control study from the USA was unable to find any significant associations between consumption of either caffeinated or decaffeinated coffee and risk of heart attack (10).
By contrast, a third Italian case control study found a significant association between the consumption of 6 or more cups of coffee per day and risk of heart attack after adjustment for confounders (19). Finally, a Swedish case control study showed that consumption of boiled coffee rather than filtered coffee was associated with increased risk of a first nonfatal heart attack (20). However, this result could be interpreted as suggesting that boiled coffee consumption helps people survive a heart attack.
South Perth, Victoria,
Logan City, Queensland,
Madison, Wisconsin, USA
Broken Hill, Australia