Association of Coffee Consumption With Overall and Cause-specific Mortality in a Large US Prospective Cohort Study

Erikka Loftfield; Neal D. Freedman; Barry I. Graubard; Kristin A. Guertin; Amanda Black; Wen-Yi Huang; Fatma M. Shebl; Susan T. Mayne; Rashmi Sinha

Disclosures

Am J Epidemiol. 2015;182(12):1010-1022. 

In This Article

Abstract and Introduction

Abstract

Concerns about high caffeine intake and coffee as a vehicle for added fat and sugar have raised questions about the net impact of coffee on health. Although inverse associations have been observed for overall mortality, data for cause-specific mortality are sparse. Additionally, few studies have considered exclusively decaffeinated coffee intake or use of coffee additives. Coffee intake was assessed at baseline by self-report in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Hazard ratios were estimated using Cox proportional hazards models. Among 90,317 US adults without cancer at study baseline (1998–2001) or history of cardiovascular disease at study enrollment (1993–2001), 8,718 deaths occurred during 805,644 person-years of follow-up from 1998 through 2009. Following adjustment for smoking and other potential confounders, coffee drinkers, as compared with nondrinkers, had lower hazard ratios for overall mortality (<1 cup/day: hazard ratio (HR) = 0.99 (95% confidence interval (CI): 0.92, 1.07); 1 cup/day: HR = 0.94 (95% CI: 0.87, 1.02); 2–3 cups/day: HR = 0.82 (95% CI: 0.77, 0.88); 4–5 cups/day: HR = 0.79 (95% CI: 0.72, 0.86); ≥6 cups/day: HR = 0.84 (95% CI: 0.75, 0.95)). Similar findings were observed for decaffeinated coffee and coffee additives. Inverse associations were observed for deaths from heart disease, chronic respiratory diseases, diabetes, pneumonia and influenza, and intentional self-harm, but not cancer. Coffee may reduce mortality risk by favorably affecting inflammation, lung function, insulin sensitivity, and depression.

Introduction

Approximately 80% of US adults drink coffee, and 60% drink coffee daily.[1] The high prevalence of exposure to coffee worldwide, combined with the possibility that coffee consumption poses both health benefits and risks,[2–12] has prompted numerous epidemiologic studies. Despite accumulating evidence supporting an inverse relationship between coffee consumption and overall mortality, the modest association continues to be debated.[13] In a recent study, Liu et al.[14] reported a positive association between heavy coffee consumption and mortality. However, results from the largest cohort study conducted to date suggested that coffee consumption was inversely associated with overall mortality among older adults.[15] Moreover, meta-analyses of prospective studies indicate that coffee consumption is inversely related to overall mortality.[13,16,17]

Prior cohort studies have considered the association between coffee consumption and cardiovascular disease mortality; meta-analyses of these studies have observed a modest inverse association.[13,17] Fewer studies have considered associations with other major causes of death. Freedman et al.[15] considered 7 specific causes of death and observed inverse associations between coffee consumption and mortality due to heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections. Additional studies indicated that coffee consumption was inversely associated with suicide[18] and chronic liver disease mortality.[9]

We used data from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, a large population-based US cohort study, to evaluate the associations of coffee drinking with mortality from all causes and the 10 leading causes of death in the United States. The results of our analysis, which included detailed data on decaffeinated coffee consumption and use of additives (e.g., cream and sugar), enhance our understanding of the relationship between coffee consumption and mortality.

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