Cola Not Coffee May Raise Risk of High BP

NEW YORK (Reuters Health) - Habitual coffee drinking does not increase the risk of hypertension (high blood pressure) in women, but consuming cola beverages might, according to the results of a study looking at the effects of various caffeine-containing products.

"The findings should give peace of mind to women who drink a lot of coffee that their habit is not putting them at risk for high blood pressure," lead author Dr. Wolfgang C. Winkelmayer, from Brigham and Women's Hospital in Boston, told Reuters Health. Further studies are needed to determine if this is also the case in men, he added.

"The association between cola beverage use and hypertension was a big surprise to us, especially since we were careful to control for other factors known to increase the risk of hypertension, such as BMI," Winkelmayer said. "This was a surprise because this association has never been reported before and because there are no ingredients in colas that we're aware of that should have this effect."

Approximately 50 million Americans have hypertension, the researchers note in the Journal of the American Medical Association this week. Previous reports had tied caffeine intake with acute elevations in blood pressure, but the long-term effects were unclear.

The current findings stem from a study of 155,594 women who participated in the Nurses' Health Studies (NHS) I and II. The subjects were free of high blood pressure when the studies began in the early 1990s and were followed over 12 years.

During follow-up, a total of 19,541 and 13,536 cases of hypertension were observed in the NHS I and II cohorts, respectively. In both cohorts, caffeine intake was not directly linked to incident hypertension.

When an analysis by beverage type was performed, habitual coffee intake was not linked to an elevated risk of high blood pressure. By contrast, drinking cola beverages, either sugared or diet, seemed to increase the risk of hypertension significantly.

While the findings should provide reassurance to coffee drinkers, further research is needed to shed light on the association between cola beverages and hypertension, Winkelmayer said.

SOURCE: Journal of the American Medical Association, November 9, 2005.