By Harold L. Karpman, MD, FACC, FACP
Clinical Professor of Medicine, UCLA School of Medicine
Dr. Karpman reports no financial relationships relevant to this field of study.
SYNOPSIS: Regular consumption of both caffeinated and decaffeinated coffee were found to be inversely associated with risk of total mortality and mortality attributed to cardiovascular disease and neurologic diseases.
SOURCE: Ding M, et al. Association of coffee consumption with total and cause-specific mortality in three large prospective cohorts. Circulation 2016;132:2305-2315.
The associations between coffee consumption and increased risks of several disease outcomes have been well investigated. Coffee consumption in moderation has been inversely associated with increased risks for the development of type 2 diabetes mellitus, hepatic cancer, endometrial cancer, prostate cancer, skin carcinoma, neurologic diseases, and cardiovascular disease.1-7 Multiple studies have reported an inverse association between moderate coffee consumption and risk of mortality and an inverse or null association between heavy coffee consumption and mortality risk.
Because of the inconclusive results of these multiple studies, Ding et al decided to determine the association of coffee consumption with total and cause-specific mortality in three large ongoing, independent cohort studies of men and women.
Researchers analyzed coffee consumption and total mortality in the Nurses’ Health Study (NHS), consisting of 121,700 female participants; NHS II, consisting of 115,671 female participants; and the Health Professionals Follow-up Study (HPFS), consisting of 51,529 male subjects. The highest categories of consumption of total and caffeinated coffee were associated with a higher risk of all-cause mortality across the three cohorts. However, this finding was attenuated significantly after adjusting for smoking. In fact, in the entire population, coffee consumption was inversely associated with risk of mortality attributed to cardiovascular disease, nonlinearly associated with risk mortality associated with type 2 diabetes mellitus patients, and positively associated with risk of mortality attributed to lung cancer and respiratory diseases. The authors concluded that there existed a nonlinear association between coffee consumption and risk of mortality in the overall population, with moderate coffee consumption associated with lower mortality risk and high coffee consumption not associated with increased mortality risk. The authors noted that this association became linear and inverse after restricting it to the never-smokers group of patients, and therefore it was considered likely that the nonlinear association observed in the total population was attributed to the residual confounding by cigarette smoking.
COMMENTARY
It should be noted that this study analyzed the health and mortality results of coffee intake. The age-adjusted analysis revealed that the highest categories of consumption of total and decaffeinated coffee were associated with a higher risk of all-cause mortality across the three cohorts. However, the association attenuated significantly after further adjusting for cigarette smoking. Although coffee consumption was inversely associated with the risk of mortality attributed to cardiovascular disease, it was nonlinearly associated with risk mortality attributed to type 2 diabetes mellitus and positively associated with risk of mortality attributed to lung cancer and respiratory diseases. When coffee consumption was analyzed in never-smokers, it was no longer associated with risk of mortality attributed to lung cancer and respiratory disease, but was inversely associated with risk of mortality attributed to cardiovascular disease, neurologic disease, and suicide. Finally, it should be noted that the authors commented on the fact that they could not directly establish a cause-effect relationship between coffee and mortality because of the observational nature of the study design.
In conclusion, clinicians should be aware that regular consumption of both caffeinated and decaffeinated coffee was inversely associated with risk of total mortality and mortality attributed to cardiovascular disease and neurologic diseases. Patients can incorporate coffee into a healthy lifestyle without fear of coffee in and of itself causing harm.
REFERENCES
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Ding M, et al. Caffeinated and decaffeinated coffee consumption and risk of type 2 diabetes: A systematic review and a dose-response meta-analysis. Diabetes Care 2014;37:569-586.
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Je Y, et al. Coffee consumption and risk of endometrial cancer: Findings from a large up-to-date meta-analysis. Int J Cancer 2012;131:1700-1710.
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Wilson KM, et al. Coffee consumption and prostate cancer risk and progression in the Health Professionals Follow-up Study. J Nat Cancer Inst 2011;103:876-884.
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Song F, et al. Increased caffeine intake is associated with reduced risk of basal cell carcinoma of the skin. Cancer Res 2012;72:3282-3289.
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Ross GW, et al. Association of coffee and caffeine intake with the risk of Parkinson’s disease. JAMA 2000;283:2674-2679.
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Ding M, et al. Long-term coffee consumption and risk of cardiovascular disease: A systematic review and a dose response meta-analysis of prospective cohort studies. Circulation 2014;129:643-659.
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Ding M, et al. Association of coffee consumption with total and cause-specific mortality in three large prospective cohorts. Circulation 2016;132:2305-2315.
