Coffee Consumption Generally Safe in Women With CV Disease

June 16, 2011 (Madrid, Spain) — Previous studies on the influence of
coffee consumption on cardiovascular disease have shown conflicting
results, but a new analysis from the massive Nurses' Health Study suggests that coffee has no effect on the cardiovascular risk of women with known cardiovascular disease [1].
"The results of this study support the idea that people with heart
disease who drink coffee do not need to stop drinking it, because this
beverage does not increase their risk of having a fatal event," study
lead author Dr
                       Esther Lopez-Garcia (Universidad Autonoma de Madrid, Spain) told heartwire
                       
                       .The study is published online May 13, 2011 in the American Journal of Clinical Nutrition.
Lopez-Garcia and colleagues note that heavy coffee consumption was
shown to increase the risk of sudden cardiac death in a population
case-control study [2], but another study of all-cause mortality in
patients hospitalized for acute myocardial infarction (MI) found a
strongly protective effect of heavy coffee consumption after three
months but not at four years [3]. A three-year study found no
association between the cumulative consumption of nonfiltered coffee and
the risk of a second cardiovascular event [4], and a 10-year
prospective study in Sweden found that filtered coffee consumption in
the year prior to an acute MI appeared to reduce the risk of all-cause
mortality after the event [5]. As reported by heartwire
                       , a small study in Germany showed that
drinking coffee improved markers of subclinical inflammation and
oxidative stress, while increasing HDL-cholesterol levels.
Lopez-Garcia et al looked at two years of follow-up data from 11 697
women in the long-running Nurses' Health Study to determine whether
there was a link between filtered caffeinated coffee consumption and
all-cause and cardiovascular mortality. Coffee consumption is tracked on
the study's food-frequency questionnaire, which is repeated every two
to four years, so the study was able to track coffee consumption both
before and after an adverse event. The subjects were categorized by how
often they drank an 8-oz cup of coffee: one or less per month, one to 16
per month, five to seven per week, two to three cups per day, or four
or more cups per day.
In the study group, there were 1159 deaths, including 579 attributed
to cardiovascular disease. The relative risk of all-cause mortality was
about the same across categories of cumulative coffee consumption (p for
trend=0.91), as was the risk of cardiovascular mortality (p for
trend=0.76). There was also no association between caffeine intake and
either total or cardiovascular mortality.
This study adds to previous studies of coffee and heart disease
because it focused on women with less severe heart-disease
symptoms--usually just angina alone--and it was the first such study to
look at coffee drinking both before and after an event, study coauthor Dr Kenneth Mukamal (Beth Israel Deaconess Hospital, Boston, MA) told heartwire
                       . This study finds "that coffee is quite
neutral for typical women with CVD who primarily have angina or have
undergone revascularization," Mukamal said. "It's still possible that
people with acute MI have some benefit from coffee, but the bulk of the
evidence increasingly seems to be that coffee has little benefit or harm
in secondary-[prevention] populations like this."
Lopez-Garcia added that "because of the long follow-up and large size
of the cohort, we had statistical power to detect even small
detrimental effects of coffee, and we did not find any increase in the
risk of death among coffee drinkers."
The study looked at female nurses because the Nurses' Health study is
a large available data set. But nurses are a "special population
because of their knowledge of diseases and lifestyles," Lopez-Garcia
said. "So extrapolation of the results to the general population must be
done with caution." Also, although some previous studies have assessed
the effect of coffee on healthy people, "we need more research on the
effect of coffee among patients with a diagnosed disease [and] more
research on the effect of specific types of coffee on the risk of
diseases, because we now know that filtered coffee is different from
unfiltered, and they may affect health in a different way," she said.
Lopez-Garcia also cautioned that, although coffee does not appear to
contribute to cardiovascular risk, "these patients still need to check
with their doctor if they have insomnia, anxiety, or uncontrolled blood
pressure--problems that can be worsened by coffee. Because of these side
effects of coffee, it is prudent to recommend moderate coffee
consumption."
                       The study was supported by the National Institutes of Health, the Ministry of Health in Spain, and the American Heart Association.

References

1. Lopez-Garcia E, Rodriguez-Artalejo F, Li TY, et al. Coffee consumption and mortality in women with cardiovascular Disease. Am J Clin Nutr 2011; DOI:10.3945/ajcn.110.010249. Available at: http://www.ajcn.org. Abstract
   
2. de Vreede-Swagemakers JJ, Gorgels AP, Weijenberg MP,
   et al. Risk indicators for out-of-hospital cardiac arrest in patients
   with coronary artery disease. J Clin Epidemiol 1999; 52:601–607. Abstract
   
3. Mukamal KJ, Maclure M, Muller JE, Sherwood JB,
   Mittleman MA. Caffeinated coffee consumption and mortality after acute
   myocardial infarction. Am Heart J 2004; 147:999–1004. Abstract
   
4. Silletta MG, Marfisi R, Levantesi G, et al. Coffee
   consumption and risk of cardiovascular events after acute myocardial
   infarction: results from the GISSI (Gruppo Italiano per lo Studio della
   Sopravvivenza nell'Infarto miocardico)-Prevenzione trial. Circulation 2007; 116:2944–51. Abstract
   
5. Mukamal KJ, Hallqvist J, Hammar N, et al. Coffee
   consumption and mortality after acute myocardial infarction: the
   Stockholm Heart Epidemiology Program. Am Heart J 2009; 157:495–501. Abstract