Coffee intake and risk of hypertension: the Johns Hopkins precursors study.
BACKGROUND
Whether the increase in blood pressure with coffee drinking seen in clinical trials persists over time and translates into an increased incidence of hypertension is not known.


METHODS
We assessed coffee intake in a cohort of 1017 white male former medical students (mean age, 26 years) in graduating classes from 1948 to 1964 up to 11 times over a median follow-up of 33 years. Blood pressure and incidence of hypertension were determined annually by self-report, demonstrated to be accurate in this cohort.


RESULTS
Consumption of 1 cup of coffee a day raised systolic blood pressure by 0.19 mm Hg (95% confidence interval, 0.02-0.35) and diastolic pressure by 0.27 mm Hg (95% confidence interval, 0.15-0.39) after adjustment for parental incidence of hypertension and time-dependent body mass index, cigarette smoking, alcohol drinking, and physical activity in analyses using generalized estimating equations. Compared with nondrinkers at baseline, coffee drinkers had a greater incidence of hypertension during follow-up (18.8% vs. 28.3%; P =.03). Relative risk (95% confidence interval) of hypertension associated with drinking 5 or more cups a day was 1.35 (0.87-2.08) for baseline intake and 1.60 (1.06-2.40) for intake over follow-up. After adjustment for the variables listed above, however, these associations were not statistically significant.


CONCLUSIONS
Over many years of follow-up, coffee drinking is associated with small increases in blood pressure, but appears to play a small role in the development of hypertension.
Klag
Michael J
MJ
The Johns Hopkins Precursors Study, 2024 E Monument St, Suite 2-200, Baltimore, MD 21205-2223, USA.
Wang
Nae-Yuh
NY
Meoni
Lucy A
LA
Brancati
Frederick L
FL
Cooper
Lisa A
LA
Liang
Kung-Yee
KY
Young
J Hunter
JH
Ford
Daniel E
DE
D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D003069:Coffee / Q000009:adverse effects*; D015331:Cohort Studies; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000139:chemically induced* / Q000503:physiopathology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D018570:Risk Assessment; D013997:Time Factors
D003069:Coffee