Drinking too much coffee may cut your life short. According to a new study, excessive coffee drinking in individuals under the age of 55 is associated with a more than 50 percent increased mortality risk.

The study, led by researchers from the Arnold School of Public Health, University of South Carolina, studied the coffee consumption of more than 40,000 individuals. The researchers discovered that consuming more than 28 cups of coffee a week, an average of more than four cups a day, was associated with a 21 percent increased mortality risk. Based on age group, there was a 50 percent increased mortality risk for those under 55, while heavy coffee consumption was not associated with any increased mortality risk for those over 55.

The end date of the study showed the association between heavy coffee consumption, defined in this study as more than four cups a day, with increased mortality risk. Compared to individuals who did not drink coffee, men under 55 had a 56 percent increased mortality risk, while women under 55 had a two-fold increased mortality risk. The researchers concluded that coffee consumption was not associated with an increased risk of death from cardiovascular disease.

The research on mortality risk, which means the chance of death from all causes, is relevant to millions of coffee drinkers, especially as more people drink coffee more often these days. The study cites a recent National Coffee Drinking Study from the National Coffee Association, which determined that more than 60 percent of Americans drink coffee as part of their daily routine. The average amount of coffee consumed per day was just over three cups.

Previous research about coffee consumption and its health effects has been inconclusive, but the new research does find a significant association between heavy coffee consumption and increased mortality risk. Some research has shown that coffee may have some potential benefits, such as improved cognitive function, and the antioxidants found in coffee may lead to a reduction in inflammation. The researchers also noted that there have been other studies that have associated coffee with adverse health effects, which have found links between excessive coffee consumption and the release of epinephrine, also known as adrenaline; increased blood pressure; and increased homocysteine levels. High levels of the amino acid have been linked to cardiovascular disease, possibly as a marker, while lowering homocysteine levels has shown no effect in reducing the cardiovascular disease risk.

Researchers collected data from the Aerobics Center Longitudinal Study (ACLS) cohort, held between 1979 and 1998, which involved 45,000 individuals and a follow-up period of 16 years. The volunteers filled out surveys about coffee consumption and other habits, as well as a personal medical history and a family medical history.

In the 17-year median follow-up of the study, there were a reported 2,512 deaths, with 32 percent of those deaths due to cardiovascular disease. The initial follow-up discovered an association between two cardiovascular disease risks, smoking and lower cardiorespiratory fitness -- and heavy coffee consumption, as those who drank more coffee were more likely to smoke and have poorer fitness.

Based on their research, and previous studies, the lead authors, Junxiu Liu and Xuemei Sui, believe heavy coffee consumption could lead to an increased mortality risk by making the adverse health effects associated with coffee worse. “Therefore, we hypothesize that the positive association between coffee and mortality may be due to the interaction of age and coffee consumption, combined with a component of genetic coffee addiction,” the researchers said in a statement.

The researchers recommend that individuals under 55 not consume more than four cups of coffee a day. Further studies can determine any association between long-term consumption with mortality risk or if a reduction in coffee consumption over the years can reduce mortality risk. The study was published in the journal Mayo Clinic Proceedings.

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