Washington: Drinking four cups of coffee a day may endanger health in under-55s, a large study on over 40,000 individuals has claimed.
Scientists have found a greater than 50 per cent increased mortality risk in both men and women younger than 55 years of age who drank more than 28 cups of coffee a week.
The study of more than 40,000 individuals suggests that younger people in particular may need to avoid heavy coffee consumption.
The study found no adverse effects in heavy coffee drinkers aged over 55.
A multicentre research team investigated the effect of coffee consumption on death from all causes and deaths from cardiovascular disease in the Aerobics Center Longitudinal Study (ACLS) cohort, with an average follow-up period of 16 years and a relatively large sample size of over 40,000 men and women.
Between 1979 and 1998, nearly 45,000 individuals aged between 20 and 87 years old 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 there were 2,512 deaths (men: 87.5 per cent; women: 12.5 per cent), 32 per cent of these caused by cardiovascular disease.
Those who consumed higher amounts of coffee (both men and women) were more likely to smoke and had lower levels of cardiorespiratory fitness.
Younger men had a trend towards higher mortality even at lower consumption, but this became significant at about 28 cups per week where there was a 56 per cent increase in mortality from all causes.
Younger women who consumed more than 28 cups of coffee per week also had a greater than two-fold higher risk of all-cause mortality than those who did not drink coffee.
“Significantly, the results did not demonstrate any association between coffee consumption and all-cause mortality among older men and women,” said senior investigator Steven H Blair, of the Department of Biostatistics and Epidemiology, Arnold School of Public Health, University of South Carolina.
“It is also important to note that none of the doses of coffee in either men or women whether younger or older had any significant effects on cardiovascular mortality,” Blair said.
The study was published in journal Mayo Clinic Proceedings.
