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Health See other Health Articles Title: Medscape's take on coffee and health Editors' Recommendations Lower Risk for Prostate Cancer Recurrence With Daily Coffee Heavy Coffee Consumption Linked With Risk of All-Cause Death Best Evidence Review of Health Effects of Coffee Coffee is one of the most frequently consumed beverages on earth, yet there remain many questions regarding its effects on health. A recent observational study made headlines for finding a positive association between heavy coffee consumption and an increased risk for death among men, but the research had some substantial limitations. Other research certainly suggests that coffee can reduce the risk for diabetes and cardiovascular events. Overall, however, patients will probably have far more to gain by addressing other lifestyle and diet issues besides coffee drinking in their quest for a longer, happier life. The Study Liu J, Sui X, Lavie CJ, et al. Association of coffee consumption with all-cause and cardiovascular disease mortality. Mayo Clin Proc. 2013 Aug 15. [Epub ahead of print] The Background "Doctor, I made some of those changes we talked about last time!" my patient relates with enthusiasm. I am genuinely excited. Ten tortillas per day, lots of Hogan's Heroes reruns, and problem alcohol drinking is no way to go through life, son. "I stopped drinking coffee!" And my hopes vanish faster than the Baconator® my patient inhaled immediately before his appointment with me. Coffee?! That was never part of the conversation. I can't help but look at my e-chart; yep, 1 cup of coffee each morning. In my analysis, he's safe as kittens regarding any health risk from coffee consumption. This scene has played out time and again in my practice, and it has reinforced to me that many adults consider coffee drinking a guilty pleasure. If so, there are many guilty individuals out there. According to trade association reports, 83% of US adults now drink coffee, a 5% increase since 2012 and part of an upward trend over the past 2 decades.[1] The majority of Americans drink coffee on a daily basis, and the average number of cups per day among daily drinkers is 3.1.[2] But what are the health risks associated with that cup of joe? A new study will give anyone in line at their favorite coffee shop something serious to consider This prospective study recruited adults between the ages of 20 and 87 years for over 30 years, ending in 2002. Patients with a history of cardiovascular disease, cancer, or abnormal exercise stress testing were excluded from the current analysis. Participants completed health questionnaires that included questions regarding coffee consumption. They also underwent a baseline examination that included laboratory analyses and an exercise stress test. Mortality data were culled from national and state databases. The main study outcome was the relationship between coffee consumption and mortality risk. These results were adjusted to account for demographics, chronic disease, and other health habit information. They were not stratified according to lab results. Data for study analysis came from 43,727 adults; 77% of the cohort was male, and the average age at the time of enrollment was 43 years. Participants were predominantly white, at the higher end of the socioeconomic spectrum, and well educated. Approximately one quarter of the study cohort had hypertension or hyperlipidemia. A minority of participants (19% of men and 21% of women) never drank coffee, while approximately a third (35.2% of men and 33.5% of women) drank 22 or more cups of coffee per week. Coffee consumption was associated with higher rates of smoking and lower levels of cardiorespiratory fitness. The most surprising finding from the multivariate adjustment analysis was that men who drank at least 28 cups of coffee per week experienced a hazard ratio of 1.21 for all-cause mortality (95% confidence interval, 1.04-1.40) when compared with men who did not drink coffee. There were also nonsignificant increases in the risk for mortality associated with drinking any amount of coffee, from 1 to 28 cups per week among men. However, there was no significant effect of coffee consumption on the risk for mortality among women. An association between heavy coffee consumption and a higher risk for cardiovascular mortality specifically was found on initial analysis among men, but this association was rendered nonsignificant after adjustment for cardiorespiratory fitness. Subgroup analysis found that any mortality risk associated with coffee was most pertinent for men and women younger than 55 years of age. Adjustment for body mass index did not significantly alter the study's main findings, and coffee did not promote a higher risk for mortality among smokers. The strengths of this study are its size and length of follow-up. It would be difficult to create meaningful results for mortality outcomes from a smaller study. The natural limitation to an observational study is confounding data, and the researchers made adjustments to account for important confounders, including an objective test to measure exercise tolerance. They did not adjust their results based on laboratory data such as lipid levels. This research has other major limitations. Participants' coffee consumption was measured only at baseline and changes were not assessed. While the researchers noted that adults' coffee-drinking habits change little over time, certainly the culture of coffee and coffee consumption has undergone a revolution during the study period between 1971 and 2002. It is hard to believe that there have not been changes in the ways that people prepare and consume coffee over 3 decades. This leads to another major study limitation: a failure to define their main variable. Not only was the type of coffee -- caffeinated vs decaffeinated, for example -- not evaluated as part of the study methods, but the authors failed to define the measurement of a cup of coffee in the first place. In America's "Supersize It!" culture, there are some massive cups of coffee out there (the average coffee mug holds 9 ounces), so any reasonable analysis should account for the exact volume of coffee consumed.[2 This is not the first study performed on the health effects of coffee, and the subject remains controversial. It is interesting that the results of this study buck the trend of recent, high-quality research that suggests that coffee improves health outcomes. Coffee can raise blood pressure acutely, but the consensus appears to be that it has a negligible role in promoting hypertension. In one systematic review of observational studies, only mild coffee consumption of 1-3 cups per day was associated with a higher risk for hypertension compared with no coffee consumption.[3] A more recent review found that the cumulative effect of coffee consumption on blood pressure was less than 1 mm Hg, and coffee did not promote hypertension.[4] Coffee has more mixed effects on other important cardiovascular risk factors. A meta-analysis of 12 studies found that coffee increased serum levels of total cholesterol, low-density lipoprotein cholesterol, and triglycerides, with a dose-response effect.[5] In contrast, a meta-analysis of 18 studies with over 400,000 participants in total found that each additional cup of coffee consumed daily was associated with a 7% reduction in the risk for incident type 2 diabetes.[6] Given these variable effects on cardiovascular disease risk factors, how does coffee consumption affect the rates of actual cardiovascular events? Previous research found a positive association between coffee intake and the risk for either myocardial infarction or cardiovascular death.[7] However, a recent review found that moderate coffee consumption reduced the risk for heart failure, with a peak protective effect at 4 servings per day.[8] This same review also found that high levels of coffee consumption might increase heart failure risk. A review of 9 cohort studies found that at least 4 cups of coffee per day reduced the risk for stroke by 17% compared with abstinence from coffee.[9] What about mortality outcomes among coffee drinkers vs nondrinkers? Research is mixed in this area as well. In an observational study of 37,742 Japanese women, coffee consumption had no significant effect on the overall risk for mortality, but there was a clear reduction in the risk for death due to coronary heart disease among coffee drinkers.[10] Another study examined mortality outcomes associated with coffee among 3837 patients with diabetes.[11] Like the current study by Liu and colleagues, it featured a broad age range among its subjects. However, in contrast to the current research, coffee consumption was associated with a lower risk for mortality, even at levels of greater than 6 cups per day. Finally, data from the Health Professionals Follow-Up Study and Nurses' Health Study, which featured similar largely white and well-educated populations in comparison with the current study, demonstrated no effect of coffee consumption on the risk for mortality among men and a lower risk for mortality among women who drank coffee.[12] Again, the benefit among women was principally for cardiovascular mortality. this study was limited to men at the highest levels of coffee consumption. Other good evidence suggests that coffee is not deleterious to health and does not promote early mortality. Moderation is key to most things in life, and individuals who are heavy coffee drinkers should consider reining in their rampant coffee habit. However, patients may also overestimate the risks of drinking coffee. If they choose to cut back on moderate consumption of coffee, physicians should inform them that they may not be reducing their risk for diabetes or improving their for mortality. At the same time, such changes in and of themselves can be empowering and can serve as teachable moments to encourage other salutary behaviors that have a better chance of improving morbidity and mortality. Clinical Pearls • The current study finds that coffee is associated with a higher risk for mortality but only among men who drank an average of at least 4 cups of coffee per day. There were significant limitations in this observational study. • Previous research has found that coffee consumption can increase serum lipid levels. Coffee appears to have a negligible effect on the risk for hypertension. • In contrast, coffee consumption appears to reduce the risk for incident diabetes. • The overall record of coffee on cardiovascular and mortality outcomes is mixed. The evidence appears strongest for a reduction in the risk for cardiovascular death among women who drink coffee. • There is insubstantial evidence to recommend against moderate consumption of coffee among adults. Poster Comment: More interesting would be inclusion of the amount of sugar added to the coffee. Post Comment Private Reply Ignore Thread
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