Coffee consumption not linked to hypertension in women

Although the effect in men is still unknown, it appears that even a high rate of coffee consumption has no negative effect on hypertension in women.

“Women can indulge in coffee and do so without feeling guilty that they might put themselves at greater risk of developing high blood pressure,” Wolfgang C. Winkelmayer, MD, associate physician at Brigham and Women’s Hospital, told Cardiology Today.

“This does not necessarily mean coffee is therapeutic,” Winkelmayer said, adding that there are no data in the literature to suggest this relationship in men.

Winkelmayer was the corresponding author on a recent study in the Journal of the American Medical Association. Researchers used the Nurses Health Study I & II databases, which included information on 155,594 women who were free of hypertension.

“Up to this point there have been several short-term studies that showed coffee causing an immediate increase in blood pressure and heart rate,” Winkelmayer said. “However, even in the short studies there was evidence that this immediate effect might taper off, and there was no real-long term data available.”

12 years

The mean age of women in the Nurses Health Study I was 55 years. Mean BMI was a little less than 25; mean blood pressure was 121 mm Hg/75 mm Hg. Approximately 42% had a family history of hypertension.

Women in the Nurses Heart Study II were younger, with a mean age of 36 years. These women also had lower mean systolic blood pressure at approximately 113 mm Hg. About 50% had a family history of hypertension.

Participants were divided into quintiles of caffeine consumption, based on dietary questionnaires, which ranged from <20 mg/d in the lowest quintile to approximately 600 mg/d in the highest quintile. Caffeine intake was positively related to alcohol consumption and smoking status.

All other baseline characteristics did not differ materially across quintiles of caffeine consumption.

Participants were followed for 12 years, and 33,077 incident cases of physician-diagnosed hypertension were reported.

Coffee not cola

Compared with participants in the lowest quintile of caffeine consumption, those in the third quintile had a 14% increased risk of hypertension in the NHS I study and a 15% increased risk of hypertension in NHS II. However, those in the highest quintile had no increased risk of hypertension in either database, an effect that did not change after multivariate analysis.

Coffee appeared to have no effect on hypertension, but researchers noted that tea consumption increased hypertension risk in the NHS II cohort.

Caffeinated cola, both sugar and diet, was positively associated with hypertension in both the NHS I cohort (P=.03) and NHS II cohort (P<.001). – by Jeremy Moore

For more information:

• Winkelmayer WC, Stampfer MJ, Willett WC, Curhan GC. Habitual caffeine intake and the risk of hypertension in women. JAMA. 2005;294:2330-2335.