Coffee Intake not linked to increased deaths

Coffee Intake Not Linked to Increased Mortality in Men or Women

News Author: Laurie Barclay, MD
CME Author: Charles Vega, MD
Ann Intern Med. 2008;148:904-914

June 20, 2008 — Coffee intake does not increase the risk for all-cause mortality in men or women and may decrease risk for cardiovascular mortality, according to the results of a study reported in the June 17 issue of the Annals of Internal Medicine.

"Coffee consumption has been linked to various beneficial and detrimental health effects, but data on its relation with mortality are sparse," write Esther Lopez-Garcia, PhD, from the Harvard School of Public Health, Brigham and Women's Hospital, and Harvard Medical School in Boston, Massachusetts, and colleagues. "Several studies have suggested that coffee might decrease the risk for some types of cancer, such as liver, colon, oral, pharyngeal, and esophageal. The objective of this study was to assess the association of coffee consumption with all-cause, cardiovascular disease (CVD), and cancer mortality."

The investigators used sex-specific Cox proportional hazard models to investigate the association between coffee consumption and the incidence of all-cause and disease-specific mortality in the prospective Health Professionals Follow-up Study and Nurses' Health Study. The study cohort consisted of 41,736 men and 86,214 women with no history of CVD or cancer at baseline.

Coffee consumption was first measured in 1986 for men and in 1980 for women and then every 2 to 4 years through 2004. During an 18-year follow-up, there were 6888 documented deaths (2049 from CVD and 2491 from cancer) in men and 11,095 deaths (2368 from CVD and 5011 from cancer) in women.

Both in men and in women, the relative risks for all-cause mortality across categories of coffee consumption decreased with increasing coffee intake, after adjustment for age, smoking, and other CVD and cancer risk factors. Compared with consumption of less than 1 cup per month, consumption of 6 or more cups per day was associated with a 20% decrease in the risk in men and a 17% decrease in the risk in women.

This inverse association was independent of caffeine intake and was primarily attributed to a moderately reduced risk for CVD mortality.

After adjustment for potential confounders, coffee consumption was not statistically significantly associated with the risk for cancer death.

Intake of decaffeinated coffee was linked to a small decrease in all-cause and CVD mortality rates.

The primary limitation of this study is reliance on self-report for estimated coffee consumption. The cohort was restricted to health care professionals, limiting generalizability.

"Regular coffee consumption was not associated with an increased mortality rate in either men or women," the study authors write. "The possibility of a modest benefit of coffee consumption on all-cause and CVD mortality needs to be further investigated. . . . Our data also suggest that this association was due to components in coffee other than caffeine."

The National Institutes of Health, the Ramón y Cajal Programme, and the American Heart Association supported this study. Two of the study authors are supported by the Ramón y Cajal Programme and the American Heart Association The other 3 study authors have disclosed no relevant financial relationships.

Clinical Context

Coffee is a complex substance with multiple physiologic effects. Previous research has suggested that coffee could lower C-reactive protein levels among women with diabetes. In addition, regular coffee consumption can reduce the susceptibility of low-density lipoprotein (LDL) cholesterol to oxidation, creating more stable arterial plaques. Coffee also contains antioxidants and multiple substances that may improve insulin sensitivity. However, coffee also contains caffeine, which can inhibit insulin activity, stimulate the release of epinephrine, and acutely raise homocysteine levels.

The effect of coffee consumption on the risk for mortality remains unclear, and the current study uses 2 large databases to address this issue.

Pearls for Practice

Although some substances in coffee promote increased insulin sensitivity, caffeine does not. Coffee contains antioxidants and may reduce the rate of oxidation of LDL cholesterol.
The current study finds that coffee consumption is associated with a modest trend toward a reduction in the risk for total mortality among men and women. In particular, coffee consumption reduced the risk for cardiovascular mortality.