Clinical Question:
Does habitual caffeine intake increase the risk of hypertension in women?
Bottom Line:
Habitual caffeine consumption does not appear to increase the risk of
hypertension in women. In particular, coffee and tea are not associated with
increased risk. The development of hypertension is, however, significantly
associated with the intake of cola drinks, including both sugared and diet
versions.
Reference:
Winkelmayer WC, Stampfer MJ, Willett WC, Curhan GC. Habitual caffeine intake
and the risk of hypertension in women. JAMA 2005;294:2330-35.
Study Design:
Cohort (prospective)
Synopsis:
Caffeine acutely increases blood pressure, but the association between
habitual consumption of caffeinated beverages and incident hypertension is
uncertain. To examine the association between caffeine intake and incident
hypertension in women. Prospective cohort study conducted in the Nurses'
Health Studies (NHSs) I and II of 155,594 US women free from
physician-diagnosed hypertension followed up over 12 years (1990-1991 to
2002-2003 questionnaires). Caffeine intake and possible confounders were
ascertained from regularly administered questionnaires. We also tested the
associations with types of caffeinated beverages. Incident
physician-diagnosed hypertension. During follow-up, 19,541 incident cases of
physician-diagnosed hypertension were reported in NHS I and 13,536 in NHS
II. In both cohorts, no linear association between caffeine consumption and
risk of incident hypertension was observed after multivariate adjustment (NHS
I, P for trend = .29; NHS II, P for trend = .53). Using categorical
analysis, an inverse U-shaped association between caffeine consumption and
incident hypertension was found. Compared with participants in the lowest
quintile of caffeine consumption, those in the third quintile had a 13% and
12% increased risk of hypertension, respectively (95% confidence interval in
NHS I, 8%-18%; in NHS II, 6%-18%). When studying individual classes of
caffeinated beverages, habitual coffee consumption was not associated with
increased risk of hypertension. By contrast, consumption of cola beverages
was associated with an increased risk of hypertension, independent of
whether it was sugared or diet cola (P for trend <.001). |