Water and fluid intakes in heart disease

[Guest guest]

Hi All,

Water may be important. Although this is an epidemiology paper, many

confounders were considered and found to make no difference. The subjects

were CRONish.

The PDF is available.

Finding the opposite result for fluids other than water is interesting and

well explained by the authors.

Exercise and energy intake were factored in also.

The results and discussion add a lot in my opinion. It is difficult to say

more than they have.

Bottoms and bottles up.

Cheers, Al.

Am J Epidemiol 2002 May 1;155(9):827-33

Water, other fluids, and fatal coronary heart disease: the Adventist Health

Study.

Chan J, Knutsen SF, Blix GG, Lee JW, Fraser GE.

“Whole blood viscosity, plasma viscosity, hematocrit, and fibrinogen are

considered independent risk factors for coronary heart disease and can be

elevated by dehydration. The associations between fatal coronary heart

disease and intake of water and fluids other than water were examined among

the 8,280 male and 12,017 female participants aged 38-100 years who were

without heart disease, stroke, or diabetes at baseline in 1976 in the

Adventist Health Study, a prospective cohort study. A total of 246 fatal

coronary heart disease events occurred during the 6-year follow-up. High

daily intakes of water (five or more glasses) compared with low (two or

fewer glasses) were associated with a relative risk in men of 0.46 (95%

confidence interval (CI): 0.28, 0.75; p trend = 0.001) and, in women, of

0.59 (95% CI: 0.36, 0.97). A high versus low intake of fluids other than

water was associated with a relative risk of 2.47 (95% CI: 1.04, 5.88) in

women and of 1.46 (95% CI: 0.7, 3.03) in men. All associations remained

virtually unchanged in multivariate analysis adjusting for age, smoking,

hypertension, body mass index, education, and (in women only) hormone

replacement therapy. ….”

PMID: 11978586 [PubMed - indexed for MEDLINE]

“Water intake and risk of coronary heart disease

The clearest and most consistent association with fatal coronary heart

disease was found with

water intake (table 3). Among men, univariate analysis showed a

dose-response relation (p <

0.001). Compared with those drinking two or fewer glasses of water daily

(low), subjects

drinking from three to four glasses (medium) and five or more glasses (high)

had relative risks

of 0.65 (95 percent confidence interval (CI): 0.40, 1.05) and 0.46 (95

percent CI: 0.28,

0.75), respectively. Among women, the relative risks of drinking medium and

high levels of

water were 0.54 (95 percent CI: 0.32, 0.90) and 0.59 (95 percent CI: 0.36,

0.97),

respectively. The associations remained virtually unchanged when adjusting

for traditional risk

factors as well as for fluids other than water, energy intake, diet,

exercise, and when weight

replaced body mass index in model 2………

Fluids other than water and risk of coronary heart disease

In univariate analysis, intake of fluids other than water was associated

with increased risk of

fatal coronary heart disease (table 5). The association was statistically

significant in women who

drank five or more compared with two or fewer servings daily, with a

relative risk of 2.47 (95

percent CI: 1.04, 5.88). When adjusting for traditional risk factors, as

well as for water and

caloric intake, exercise, diet, and replacing body mass index with weight,

the point estimates

remained virtually unchanged and significance was retained. However, the

confidence intervals

around these estimates were quite wide.

We were unable to determine the degree to which juices or sugared drinks

(including soda)

might individually contribute to the increased risk of fatal coronary heart

disease in women,

because too few of this study population consumed any of these beverages

individually more

than once a day. After adjustment for water intake, the association with

intake of milk (omitting

soy milk) was close to the null and with caffeinated beverages (coffee, tea,

and caffeinated

sodas), positive but not statistically significant.

……….Those subjects who

drink more water may be more health conscious in other less clearly defined

ways. Drinking

more water may be a marker of higher physical activity or those with higher

energy intake.

However, a two-tailed Pearson's correlation test showed no correlation

between water and

energy intakes (r = 0.08, p < 0.01 and r = 0.06, p < 0.01 for males and

females, respectively)

and, when exercise and energy consumption are included in the multivariate

model, the effect

of water consumption remained. Diabetics, who may drink more fluids, are

excluded from

these analyses. That the negative association with water intake was

relatively consistent across

many subgroups of the population makes confounding less likely as an

explanation for this

effect……………

Why may coronary heart disease risk be increased with a higher intake of

fluids other than

water? Several mechanisms can be postulated. Caffeinated beverages are mild

diuretics and

thus may raise blood viscosity (44). High energy drinks such as juices and

regular sodas have

osmolalities between 556 and 836 mOsm/kg (45). Their consumption causes a

net

movement of fluid from the vascular system into the intestinal lumen,

resulting in a rapid

elevation in blood viscosity after consumption (24). Perfusing the duodenum

with a glucose

solution that has an osmolality of 456 mOsm/kg, which is lower than that of

juices and regular

soda, was observed to reduce plasma volume by 3.3 percent within 105 minutes

(46).

Further, serum triglyceride levels may be raised by drinks containing high

concentrations of

sugar, including fruit juices (47–50). In subjects drinking 2.7 glasses (640

ml) of grape

juice and three glasses (750 ml) of orange juice daily, triglyceride levels

were seen to increase

by 50 percent (51) and 30 percent (52), respectively. There is growing

evidence that

postprandial and fasting elevations of plasma triglycerides are independent

coronary heart

disease risk factors (53–58), even within the high normal range (59).

Elevated

triglyceride levels have been positively associated with coagulation factor

VII (60),

plasminogen activator inhibitor-1 (57), and thrombotic factors X (60) and IX

(57) but

inversely associated with antithrombin III (58) and plasma fibrinolytic

activity (57). We

hypothesize that higher intake of diuretic and high energy beverages results

in more frequent

and larger exposure to conditions that increase the risk of thrombosis and

atherosclerosis……..

Supported in part by National Institutes of Health [not bottled water

companies].”

Alan Pater, Ph.D.; Faculty of Medicine; Memorial University; St. 's, NF

A1B 3V6 Canada; Tel. No.: (709) 777-6488; Fax No.: (709) 777-7010; email:

apater@...