Published in the journal Mayo Clinic Proceedings, the study found a statistically significant 21 percent increased mortality among those drinking more than 28 cups of coffee a week or 4 cups of coffee a day.
The risk for death from all causes rose by more than 50 percent for men and women younger than 55 years but no adverse effects were found in heavy coffee drinkers aged over 55, it said.
University of South Carolina researchers examined coffee consumption of over 43,000 individuals aged 20 and 87 years from 1971 to 2002.
During the 17-year median follow-up period, more than 2,500 participants died.
The study found among younger men a trend toward higher mortality even at lower consumption but this became significant at about 28 cups per week where there was a 56 percent increase in mortality from all causes.
Younger women who consumed more than 28 cups of coffee per week had double the risk of dying from all causes than those who did not drink coffee, the study continued.
"For those drinking high amounts, there should be some caution as this dose is associated with at least a signal for increased total mortality in this large study, especially in those under 55 years of age," the study's co-author Xuemei Sui from University of South Carolina in Columbia told Xinhua on Friday.
Coffee has long been suspected of contributing to several chronic health conditions although earlier studies on coffee consumption in relation to deaths from all causes and deaths from coronary heart disease are limited and the results are often controversial.
"No organization has specific recommendations for coffee drinking - lots out there are based on published studies which yet reach a definite conclusion," Sui said. "My review is that it is safe to drink low doses (one to two cups and probably two to three cups per day) of coffee with even some potential benefits of the low dose. Really, moderation is key. Avoid excess drinking coffee."
source: interaksyon.com
