Colas cause, coffee prevents hypertension?

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Hi All,

Colas cause, coffee prevents hypertension? The findings are first discussed in

(1).

http://www.cbc.ca/story/science/national/2005/11/08/caffeine-bp051108.html

1. Cola linked to higher blood pressure risk in women, coffee not

Last Updated Tue, 08 Nov 2005 18:53:39 EST

CBC News

Women who don't have high blood pressure may not need to worry that drinking

coffee

will increase their risk of developing hypertension, but the picture is less

clear

for drinking cola.

Experiments show caffeine increases blood pressure and heart rate in the short

term,

although the effect seems to weaken over time.

Dr. Wolfgang Winkelmayer of the Harvard School of Public Health and colleagues

wanted to explore the long-term effect of caffeine intake, given how commonly it

is

consumed.

Over 12 years, the researchers tracked cases of hypertension diagnosed by a

physician among 155,594 mostly white, female nurses aged 55 on average. The

women

answered questionnaires about their diet and health.

" We found strong evidence to refute speculation that coffee consumption is

associated with an increased risk of hypertension in women, the study's authors

wrote in the Dec. 9 issue of the Journal of the American Medical Association.

Over the course of the study, about 33,000 were diagnosed with high blood

pressure,

a condition that increases the risk for heart disease, stroke and kidney

problems.

Women who drank more than three cups of coffee daily were about seven per cent

to 12

per cent less likely to develop high blood pressure than women who drank little

or

no coffee, the team found.

Winkelmayer said they were surprised to find that drinking cola, whether with

sugar

or sugarfree, was associated with greater risk of hypertension.

Women who drank at least four cans of sugared cola drinks daily had a 28 per

cent to

44 per cent higher risk of high blood pressure, compared with women who drank

few or

none. The effect was slightly less among those who drank sugerfree cola.

The researchers speculate something other than caffeine may be responsible for

the

increased risk of hypertension from cola, after controlling for weight changes

and

sodium content of the drinks.

Winkelmayer said there is no reason to change cola consumption based on the

results.

More research is needed to find the biological mechanism behind the association,

and

to see if it exists among other racial populations. The researchers are planning

a

similar caffeine study among male health professionals.

Current Canadian hypertension guidelines say there is no risk to coffee

consumption

among people who are not hypertensive.

Then, there is:

This Week in JAMA

JAMA. 2005;294:2273.

Caffeine Intake and Hypertension in Women

Caffeine intake may cause an acute increase in blood pressure, but whether

habitual

caffeine intake is associated with incident hypertension is not clear. Using

data

from a large prospective study in women, Winkelmayer and colleagues assessed the

relationship between caffeine intake and physician-diagnosed hypertension. They

found no association of habitual caffeine consumption with new diagnoses of

hypertension. In analyses of individual beverages, the authors found that

consumption of cola beverages but not coffee was associated with an increased

risk

of hypertension.

Habitual Caffeine Intake and the Risk of Hypertension in Women

Wolfgang C. Winkelmayer; Meir J. Stampfer; Walter C. Willett; C. Curhan

JAMA. 2005;294:2330-2335.

ABSTRACT

Context Caffeine acutely increases blood pressure, but the association between

habitual consumption of caffeinated beverages and incident hypertension is

uncertain.

Objective To examine the association between caffeine intake and incident

hypertension in women.

Design, Setting, and Participants 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.

Main Outcome Measure Incident physician-diagnosed hypertension.

Results 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).

Conclusion No linear association between caffeine consumption and incident

hypertension was found. Even though habitual coffee consumption was not

associated

with an increased risk of hypertension, consumption of sugared or diet cola was

associated with it. Further research to elucidate the role of cola beverages in

hypertension is warranted.

The results for diet sodas seemed to be of interest and available pdf provided

the

details (2).

From the available pdf comes details (2), for which the sugared colas in the

same

studies had multivariate relative risks (95% confidence interval) of 1.44

(0.98-2.11) in the Nurses’ Health Study I and 1.28 (1.01-1.62) in the Nurses’

Health

Study II.

2. Table 6. Age-Adjusted and Multivariate Relative Risks for Incident

Hypertension

According to Frequency of Diet Cola Intake

========================

Glasses or Cans diet cola per/day PTrend <1 1 2-3 =/>4

========================

Nurses’ Health Study I (1990-2002)

No. of cases 17 268 1154 662 130

Person-years 479 890 30 579 17 316 3173

Age-adjusted relative risk (95% CI) 1.00 1.16 (1.10-1.24) 1.23 (1.13-1.33)

1.37

(1.15-1.62) <.001

Multivariate relative risk (95% CI)* 1.00 1.07 (1.00-1.13) 1.06 (0.98-1.15)

1.16

(0.97-1.37) .02

Nurses’ Health Study II (1991-2003)

No. of cases 10 192 1452 1358 449

Person-years 713 971 91 144 77 398 21 265

Age-adjusted relative risk (95% CI) 1.00 1.16 (1.10-1.23) 1.33 (1.26-1.41)

1.63

(1.49-1.80) <.001

Multivariate relative risk (95% CI)* 1.00 1.05 (0.99-1.11) 1.09 (1.03-1.15)

1.19

(1.08-1.32) <.001

========================

Abbreviation: CI, confidence interval.

*Adjusted for age, body mass index, intake of alcohol, family history of

hypertension, oral contraceptive use (in Nurses’ Health Study II only), physical

activity, and smoking status, as well as the other classes of beverage.

Al Pater, PhD; email: old542000@...

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