Drinking coffee or tea regularly may lower death risk in women who suffer from diabetes, a study claims.
More than 80 per cent of the world's adult population consume caffeine daily, mostly from coffee and tea. Average daily coffee consumption is between 100 milligrammes (mg) and 300 mg per day, depending on age and country.
Many 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.
Researchers including those from the University of Porto in Portugal examined the association between varying levels of caffeine intake and mortality in over 3,000 men and women with diabetes from the 1999 to 2010.
Participants reported their caffeine intake from coffee, tea, and soft drinks when they entered the study using 24-hour dietary recalls - structured interviews to accurately assess intake for the previous 24 hours.
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 per cent less likely to die than those who consumed no caffeine.
Women who consumed 100-200mg per day had a 57 per cent lower risk of death compared with non-consumers, and for those consuming over 200mg per day - 2 regular cups of coffee - the reduced risk of death was 66 per cent.
No beneficial effect of caffeine consumption was noted in men with diabetes.
There was a decrease in cancer related mortality among women that 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 per cent reduced risk of cancer compared with women with zero caffeine consumption from tea.
However, as the overall consumption of tea was low in the study, the results must be interpreted with caution and considered as exploratory, requiring confirmation in larger studies, researchers said.
"Our study showed a dose-dependent protective effect of caffeine consumption on all-cause mortality among women," researchers said.
"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," they said.