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Caffeine may lower risk of death in women with diabetes

Two cups of coffee a day cut risk of death in female diabetics by 66%

Adrian O'Dowd

Thursday, 14 September 2017

Women with diabetes who regularly drink caffeinated coffee or tea could be reducing their risk of death compared to those who consume no caffeine, suggests research presented today at the annual European Association for the Study of Diabetes Annual Meeting being held this week in Lisbon, Portugal.

Researchers from Portugal presented findings from their as yet unpublished study* which found that the more caffeine women consumed, the lower their risk of dying compared to those who never consumed caffeine. No association was found for men with diabetes.

More than 80% of the world's adult population consume caffeine daily, mostly from coffee and tea. Average daily coffee consumption is between 100mg and 300mg per day, depending on age and country.

Many previous studies have shown a beneficial effect of drinking coffee on the risk of death from all causes in the general population, but little is known about the role of caffeine on mortality in people with diabetes.

For the new research, a group of researchers from various institutions in Portugal including the University of Porto, examined the association between varying levels of caffeine intake and mortality in 3,052 men and women with diabetes.

They used data from the 1999 to 2010 National Health Nutrition Examination Survey – a study tracking the health and nutritional status of a nationally representative sample of adults in the USA since 1971.

Participants reported their caffeine intake from coffee, tea, and soft drinks when they entered the study using 24-hour dietary recalls.

Over the course of the 11-year study, 618 people died.

The researchers found that women with diabetes who consumed up to 100mg per day (one regular cup of coffee) were 51% less likely to die than those who consumed no caffeine.

Women with diabetes who consumed 100-200mg per day had a 57% lower risk of death compared with non-consumers, and for those consuming over 200mg per day (two regular cups of coffee) the reduced risk of death was 66%.

This association was still the case even when influential factors including age, race, education level, annual family income, smoking, BMI, alcohol intake, high blood pressure, and diabetic kidney disease were taken into account.

There was no beneficial effect of caffeine consumption noted in men with diabetes.

In addition, the researchers found there was a decrease in cancer-related mortality among women who consumed more caffeine from tea.

When divided into four groups of tea consumption (zero, low, medium, high), the high caffeine from tea consumers had an 80% reduced risk of cancer compared with women with zero caffeine consumption from tea.

However, as the overall consumption of tea was low in this group, the authors warned that these results required confirmation in larger studies.

The authors concluded: “Our study showed a dose-dependent protective effect of caffeine consumption on all-cause mortality among women.

“The effect on mortality appears to depend on the source of caffeine, with a protective effect of coffee consumption on all-cause mortality and cardiovascular mortality, and a protective effect of caffeine from tea on cancer mortality among women with diabetes.

“However, our observational study cannot prove that caffeine reduces the risk of death but only suggests the possibility of such a protective effect.”


* Neves JS, Leitão Magriço LR, et al. Caffeine consumption and mortality in diabetes: and analysis of NHANES 1999-2010.

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