Unfiltered coffee may increase mortality risk
People who drank unfiltered coffee had a higher risk for mortality compared with those who drank filtered coffee, according to a study published in the European Journal of Preventive Cardiology.
“Our study provides strong and convincing evidence of a link between coffee brewing methods, heart attacks and longevity,” Dag S. Thelle, MD, PhD, professor in the department of public health and community medicine at the Institute of Medicine at the University of Gothenburg in Sweden, said in a press release. “Unfiltered coffee contains substances [that] increase blood cholesterol. Using a filter removes these and makes heart attacks and premature death less likely.”
Coffee consumption in Norway
Aage Tverdal, PhD, epidemiologist at the Norwegian Institute of Public Health, and colleagues analyzed data from 508,747 participants aged 20 to 79 years from Norway. Participants completed questionnaires on smoking habits, coffee consumption and formal education duration. Some of the questions pertaining to coffee consumption included method of brewing, type and number of cups per day.
Among participants, 59% reported they preferred filtered coffee, 20% preferred unfiltered coffee, 9% used both methods and 12% did not drink coffee.
During an average follow-up of 20 years, there were 46,341 all-cause deaths, 12,621 CVD deaths, 6,202 ischemic heart disease deaths and 2,894 deaths related to stroke.
Compared with no coffee consumption, the HRs for any death in men who consumed filtered coffee was 0.85 (95% CI, 0.82-0.9), 0.84 for men who preferred both filtered and unfiltered coffee (95% CI, 0.79-0.89) and 0.96 for men who consumed unfiltered coffee (95% CI, 0.91-1.01). For women, HRs for any deaths were 0.85 for filtered coffee (95% CI, 0.81-0.9), 0.79 for both filtered and unfiltered coffee (95% CI, 0.73-0.85) and 0.91 for unfiltered coffee (95% CI, 0.86-0.96).
HRs for CVD death in men were 0.88 for filtered coffee (95% CI, 0.81-0.96), 0.93 for filtered and unfiltered coffee (95% CI, 0.83-1.04) and 0.97 for unfiltered coffee (95% CI, 0.89-1.07). Women had an HR of 0.8 for filtered coffee (95% CI, 0.71-0.89), 0.72 for unfiltered and filtered coffee (95% CI, 0.61-0.85) and 0.83 for unfiltered coffee (95% CI, 0.74-0.93).
When researchers stratified by age, HRs increased for people aged 60 years and older. Compared with no coffee consumption, unfiltered coffee increased the HR for CVD death to 1.19 in men (95% CI, 1-1.41) and 0.98 for women (95% CI, 0.82-1.15).
The HR for death from ischemic heart disease and CVD increased when total cholesterol was excluded from the model. HR for ischemic heart disease mortality increased by 9% in participants who drank nine or more cups of unfiltered coffee per day.
“We do not know whether our findings are valid for other populations,” Tverdal and colleagues wrote. “However, it is reasonable to assume that the cholesterol-raising effect of unfiltered coffee is generalizable. Thus, a high intake of unfiltered coffee could be most unfavorable in high-risk groups.”
Importance of filtered coffee
In a related editorial, Yoshihiro Fukumoto, MD, professor and chairman of cardiovascular medicine in the department of internal medicine at Kurume University School of Medicine in Japan, wrote: “To prevent major cardiovascular events, nutrition control and appropriate physical activity are definitely required as the first step, which should be started as early as possible. Drinking filtered coffee with each meal may decrease mortality. Optimum medical treatment should also be given, if necessary. Even after a cardiovascular event, nutrition control, appropriate physical activity and optimum medical treatment should be continued, in which the consumption of filtered coffee should be 1-4 cups per day.” – by Darlene Dobkowski
Disclosures: Thelle reports he consulted for Norwegian Coffee Information. The other authors and Fukumoto report no relevant financial disclosures.