Heavy coffee consumption may endanger health in adults younger than 55

Drinking more than 28 cups of coffee per week may be unhealthy for people younger than 55, according to a recent study published in Mayo Clinic Proceedings.

A multicenter research team, including Carl J. Lavie, MD, of the Ochsner Medical Center, New Orleans, investigated the effect of coffee consumption on death from all causes and deaths from cardiovascular (CV) disease in the Aerobics Center Longitudinal Study.

More than 40,000 men and women between 1979 and 1998 were followed for an average of 16 years. Nearly 45,000 individuals between 20 and 87 years participated and returned a medical history questionnaire assessing lifestyle habits (including coffee consumption) and personal and family medical history. The investigators examined a total of 43,727 participants (33,900 men and 9,827 women) in their final analysis.

During the 17-year median follow-up period, 2,512 individuals died (men: 87.5%; women: 12.5%), with approximately one-third caused by CV disease. Those men and women who consumed higher amounts of coffee were more likely to smoke and had lower levels of cardiorespiratory fitness. All participants were followed from the baseline examination to date of death or until December 31, 2003.

Deaths from all causes and deaths from cardiovascular disease were identified through the National Death Index or by accessing death certificates. Younger men had a higher mortality risk even at lower consumption, but this became significant at about 28 cups per week where there was a 56% increase in mortality from all causes. Younger women who consumed more than 28 cups of coffee weekly also had a greater than 2-fold higher risk of all-cause mortality than those who did not drink coffee.

Dr. Lavie and colleagues found that those who reported drinking 28 or more cups of coffee per week had a 21% higher mortality during follow-up, but this was increased by 56% in men less than 55 years and double in women younger than 55 years, whereas mortality risk was not clearly increased in men or women greater than 55 years.

“There was safety from mortality with <28 cups/week and no group had increased CV mortality at any dose,” said Dr. Lavie, professor of medicine, medical director, Cardiac Rehabilitation and Prevention director, Stress Testing Laboratory, John Ochsner Heart and Vascular Institute, Ochsner Clinical School, The University of Queensland School of Medicine.

This report is important as coffee is second only to water in the beverage consumed around the world and Americans consume more than 500,000 million cups of coffee per day, Dr Lavie pointed out. According to the latest National Coffee Drinking Study from the National Coffee Association, more than 60% of American adults drink coffee every day, consuming on average just more than 3 cups a day. Coffee has long been suspected to contribute to a variety of 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.

“The take-away is that people drinking 4 or more cups of coffee per day should consider reducing some, at least to 2 to 3 cups per day,” said Dr. Lavie.