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Cola, but Not Coffee, Appears to Raise Hypertension Risk

Intake of sugared or diet caffeinated cola was associated with increased risk.

Caffeine consumption can acutely raise levels of stress hormones and blood pressure, but debate continues over the long-term influence of regular coffee drinking on the development of hypertension. Nurses’ Health Study (NHS) researchers sought to settle this question among 61,091 NHS I participants (mean age, about 55) and 94,503 NHS II participants (mean age, about 36) without histories of hypertension. During 12 years of follow-up, women completed three dietary questionnaires, and they reported hypertension diagnoses on biennial questionnaires.

Overall, 33,077 women (21.3%) reported new diagnoses of hypertension. Women in the third quintile of caffeine consumption had higher rates of hypertension than women in the lowest and highest quintiles of consumption, creating an inverse U-shaped risk curve. On multivariate analysis, hypertension risk was significantly higher among women in the third quintile than among those in the lowest quintile (relative risks: NHS I, 1.13; NHS II, 1.12). When beverage type was considered, intake of caffeinated coffee was not positively associated with risk. However, hypertension risk increased significantly as intake of sugared or diet caffeinated cola increased. A positive association between caffeinated tea and hypertension risk was noted among NHS II participants only. Adjustment for intake of sodium, magnesium, potassium, phosphorous, calcium, and analgesic drugs did not alter the findings.

Comment: These data counter the conjecture that chronic coffee drinking leads to hypertension. Although the findings were inconclusive for caffeinated tea, consumption of caffeinated cola does appear to significantly increase a woman’s risk for hypertension. Perhaps other ingredients in cola-type soft drinks are responsible, such as the caramel coloring, which has been implicated in diabetes risk. Because even diet colas were associated with risk, women cannot assume that zero calorie equals zero risk.

— Marian C. Limacher, MD

Published in Journal Watch Women's Health January 10, 2006

Citation(s):

Winkelmayer WC et al. Habitual caffeine intake and the risk of hypertension in women. JAMA 2005 Nov 9; 294:2330-5.

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