'The association between caffeine and heart failure risk reduction was surprising. When the researchers examined this further, they found caffeine consumption from any source appeared to be associated with decreased heart failure risk, and caffeine was at least part of the reason for the apparent benefit from drinking more coffee.

In the Cardiovascular Health Study however there was no increase or decrease in risk of heart failure associated with drinking decaffeinated coffee.

Drinking decaffeinated coffee appeared to have an opposite effect on heart failure risk - significantly increasing the risk of heart failure in the Framingham Heart Study.

In the Atherosclerosis Risk in Communities Study, the risk of heart failure did not change between 0 to 1 cup per day of coffee however, it was about 30% lower in people who drank at least 2 cups a day.

In the Framingham Heart and the Cardiovascular Health studies, the risk of heart failure over the course of decades decreased by 5-to-12% per cup per day of coffee, compared with no coffee consumption.

In all three studies, people who reported drinking one or more cups of caffeinated coffee had an associated decreased long-term heart failure risk.

Across the three studies, coffee consumption was self-reported, and no standard unit of measure were available. To analyze the outcomes of drinking caffeinated coffee, researchers categorized consumption as 0 cups per day, 1 cup per day, 2 cups per day and ?3 cups per day. Each study included at least 10 years of follow-up, and, collectively, the studies provided information on more than 21,000 U.S. Kao and colleagues used machine learning through the American Heart Association's Precision Medicine Platform to examine data from the original cohort of the Framingham Heart Study and referenced it against data from both the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study to help confirm their findings.

'Studies reporting associations with outcomes remain relatively limited due to inconsistencies in diet assessment and analytical methodologies, as well as inherent problems with self-reported dietary intake.' 'The risks and benefits of drinking coffee have been topics of ongoing scientific interest due to the popularity and frequency of consumption worldwide,' said Linda Van Horn, Ph.D., R.D., professor and Chief of the Department of Preventive Medicine's Nutrition Division at the Northwestern University Feinberg School of Medicine in Chicago, and member of the American Heart Association's Nutrition Committee. Kao, M.D., senior author of the study, assistant professor of cardiology and medical director at the Colorado Center for Personalized Medicine at the University of Colorado School of Medicine in Aurora, Colorado. 'While smoking, age and high blood pressure are among the most well-known heart disease risk factors, unidentified risk factors for heart disease remain,' according to David P. Coronary artery disease, heart failure and stroke are among the top causes of death from heart disease in the U.S.

Decaffeinated coffee health risks