Decaffeinated beverages, promoted as a healthy alternative to their caffeinated equivalents, may actually increase the risk of developing rheumatoid arthritis, a new study suggests.
Researchers at the University of Alabama, US, studied more than 31,336 women aged 55-69.
Those who reported consuming four or more cups of decaffeinated coffee a day were more than twice as likely to develop rheumatoid arthritis, compared to women who never drank decaf, the study reveals.
Previous studies done by Finnish researchers had origianlly established a link between overall coffee intake and RA in March 2000, commented lead author Dr. Ted Mikuls, a rheumatologist in the division of clinical immunology and rheumatology at the University of Alabama.
The study found people who drank 11 or more cups of coffee a day were nearly 15 times more likely to develop RA than those who did not drink coffee.
But "the study looked at [all] coffee, with really no breakdown of coffee types," says Mikuls.
The exact mechanisms behind the most recent findings are "purely speculation" at this point, says Mikuls.
One idea is that it may have something to do with the way decaf coffee was processed.
The new study also found that drinking more than three cups of tea a day is associated with an approximated 60 per cent decrease in RA risk compared to drinking no tea at all.
Because the study did not determine which specific types of tea women consumed, it is very difficult to pinpoint which teas might be of benefit and why.
The study's authors stressed that more research is required in order to corroborate their results.
The findings were presented this month at the American College of Rheumatology Annual Scientific Meeting in San Francisco.