(Stroke. 1999;30:1772-1779.)
© 1999 American Heart Association, Inc.
Original Contributions |
Prospective Study of Calcium, Potassium, and Magnesium Intake and Risk of Stroke in Women
From the Channing Laboratory (H.I., M.J.S., J.E.M., K.R., G.A.C., F.E.S., W.C.W.) and the Division of Preventive Medicine (J.E.M., K.R., C.H.H.), Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, and Departments of Epidemiology (M.J.S., J.E.M., C.H.H., G.A.C., W.C.W.) and Nutrition (M.J.S., W.C.W.), Harvard School of Public Health, Boston, Mass.
Correspondence to Meir J. Stampfer, MD, Channing Laboratory, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Ave, Boston, MA 02115. E-mail meir.stampfer{at}channing.harvard.edu
 |
Abstract |
|---|
 Top Abstract IntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
Background and Purpose—High intakes of calcium, potassium, and magnesium have been hypothesized to reduce risks of cardiovascular disease, but only a few prospective studies have examined intakes of these cations in relation to risk of stroke.
Methods—In 1980, 85 764 women in the Nurses' Health Study cohort, aged 34 to 59 years and free of diagnosed cardiovascular disease and cancer, completed dietary questionnaires from which we calculated intakes of calcium, potassium, and magnesium. By 1994, after 1.16 million person-years of follow-up, 690 incident strokes (129 subarachnoid hemorrhages, 74 intraparenchymal hemorrhages, 386 ischemic strokes, and 101 strokes of undetermined type) had been documented.
Results—Intakes of calcium, potassium, and magnesium were each
inversely associated with age- and smoking-adjusted relative risks of
ischemic stroke, excluding embolic infarction of nonatherogenic
origin (n=347). Adjustment for other cardiovascular
risk factors, including history of hypertension, attenuated these
associations, particularly for magnesium intake. In a
multivariate analysis, women in the highest
quintile of calcium intake had an adjusted relative risk of
ischemic stroke of 0.69 (95% CI, 0.50 to 0.95;
P for trend=0.03) compared with those in the lowest
quintile; for potassium intake the corresponding relative risk was 0.72
(95% CI, 0.51 to 1.01; P for trend=0.10). Further
simultaneous adjustment for calcium and potassium intake
suggested an independent association for calcium intake. The
association of risk with calcium intake did not appear to be log
linear; the increase in risk was limited to the lowest quintile of
intake, and intakes >
600 mg/d did not appear to reduce risk of
stroke further. The inverse association with calcium intake was
stronger for dairy than for nondairy calcium intake. Intakes of
calcium, potassium, and magnesium were not related to risk of other
stroke subtypes.
Conclusions—Low calcium intake, and perhaps low potassium intake, may contribute to increased risk of ischemic stroke in middle-aged American women. It remains possible that women in the lowest quintile of calcium intake had unknown characteristics that made them susceptible to ischemic stroke.
Key Words: calcium • diet • magnesium • potassium • stroke
|
Introduction |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
In observational studies, intakes of calcium,1 2 potassium,3 and magnesium2 4 5 have been inversely associated with blood pressure or risk of hypertension; clinical trials6 7 8 9 10 have tended to find that potassium had the strongest hypotensive effects. High intake of these cations may prevent stroke because hypertension is a strong risk factor for stroke.11 Moreover, animal experiments suggest additional mechanisms for these cations in the prevention of stroke.12 13 14 15 16 17 18 Stroke mortality in rats was reduced after supplementation with calcium19 and potassium,16 but not with magnesium.18 Only a few prospective studies have addressed the relation between intake of these cations and risk of stroke, and data in women are sparse.20 21 An inverse relation between calcium intake and risk of ischemic stroke was reported from a study of Japanese-American men.20 An inverse relation between potassium intake and stroke risk was reported from studies of American white men and women,21 Japanese-American men,22 and US health professional men.23 We investigated the relation between intake of these cations and the incidence of stroke among US women followed prospectively for 14 years in the Nurses' Health Study.
|
Subjects and Methods |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
The Nurses' Health Study began in 1976, when 121 700 female registered nurses (98% white) living in 11 states completed questionnaires about lifestyle factors and medical history, including previous cardiovascular disease, cancer, diabetes, hypertension, and high serum cholesterol levels.24 Every 2 years, follow-up questionnaires are sent to these women so that information can be updated and newly diagnosed major illnesses identified.
Ascertainment of Diet
In 1980, we collected data on usual dietary intake using a
semiquantitative food frequency questionnaire.25 For each
food (61 items), a commonly used unit or portion size was specified,
and each woman was asked how often on average during the previous year
she had consumed that amount. Nine responses were possible, ranging
from "almost never" to "
6 times per day." The average daily
intake of nutrients was calculated by multiplying the frequency of
consumption of each item by the nutrient content and totaling the
nutrient intake for all food items. Nutrient intake was adjusted for
total energy intake with the use of the residual
approach.26 The reproducibility and validity of this
questionnaire have been reported elsewhere.25 27 28 In a
validation study among 200 cohort participants conducted in 1986, the
correlations between cation intake assessed by the expanded dietary
questionnaire used in 1984, 1986, and 1990 and by two 1-week diet
records were 0.62 for calcium, 0.61 for potassium, and 0.76 for
magnesium after within-person variation in the diet records was
taken into account.29
A total of 98 462 women returned the 1980 dietary questionnaire. We
excluded women who left 10 items blank, whose reported total food
intakes were implausible, or who had a history of cancer (except
nonmelanoma skin cancer), angina, myocardial infarction, stroke, or
other cardiovascular diseases; 86 368 women remained
for the analyses.
Ascertainment of Stroke
Women who reported a nonfatal stroke on a follow-up
questionnaire were asked for permission to review their medical
records. The 18.4% of nonfatal strokes for which confirmatory
information was obtained by telephone or letter, but for which no
medical records were available, were regarded as probable. Fatal
strokes were initially ascertained by reports from relatives or postal
authorities and a search of the National Death Index30 and
were then documented by medical records and death certificates.
Mortality follow-up was >98% complete.30 The 22.3% of
fatal strokes that were confirmed by telephone, letter, or death
certificate, but for which no medical records were available, were
regarded as probable. Medical records were reviewed by physicians
blinded as to dietary and other risk factors.
Strokes were confirmed by medical records according to the criteria
of the National Survey of Stroke,31 which requires a
constellation of neurological deficits of sudden or rapid onset lasting
24 hours or until death; strokes were categorized as
subarachnoid hemorrhages, intraparenchymal
hemorrhages, ischemic strokes (thrombotic or embolic),
or strokes of undetermined type. For embolic infarction, sources of
emboli were recorded. Atherogenic origins of emboli included
ulcerating atherosclerotic plaques in the carotid artery, mural thrombi
associated with myocardial infarction, and embolic strokes as a
consequence of surgery for coronary heart disease. Other
sources of emboli, such as valvular heart disease and bacterial
endocarditis, were regarded as nonatherogenic origin. Atrial
fibrillation also was regarded as largely nonatherogenic origin because
the major predisposition to nonvalvular atrial fibrillation is
congestive heart failure rather than coronary
disease.32 Strokes were regarded as incident if they
occurred after the date of return of the 1980 questionnaire but before
June 1, 1994. Only confirmed and probable strokes were considered in
the analyses for all stroke. For analyses of
ischemic stroke and the other specific stroke types, only
confirmed cases were considered.
Statistical Analyses
The analyses were based on the incidence of stroke
during 14 years of follow-up (1980–1994). For each woman,
person-months of follow-up were allocated according to 1980 exposure
variables and were updated according to information on biennial
follow-up questionnaires until death or an end point (stroke) was
reached or until May 31, 1994. From the 1980 questionnaire, we used
information on the intake of calcium, potassium, magnesium, and 
-3
polyunsaturated fatty acids and on regular exercise. We present
results based on the 1980 dietary variables without updating
because we were most interested in the long-term effects of intake of
cations on risk of stroke. Updating of intakes of these nutrients using
the 1984, 1986, and 1990 questionnaires yielded generally similar
associations with risk of stroke. In the updated analyses, for
example, the incidence of stroke during 1980–1984 was related to
nutrient intakes reported on the 1980 questionnaire, and the incidence
during 1984–1986 was related to nutrient intakes reported on the 1984
questionnaire.
To examine the relation between use of cation supplements and risk of stroke, subsequent dietary questionnaires were used because information on these individual supplements was not available from the 1980 questionnaire; only multivitamin supplement use was taken into account to assess calcium intake in 1980. Data on use of calcium supplements, including dose, were available for 1982, 1984, 1986, and 1990. Data on magnesium supplement use (no data on dose) were obtained in 1984, 1986, and 1990. For calcium and magnesium supplements, the information was updated in the primary analysis. Use of calcium supplements changed markedly during the follow-up (10% in 1982, 26% in 1984, 52% in 1986, and 35% in 1990), whereas magnesium supplement use did not (4% in 1984 and 1986 and 3% in 1990). Information about potassium supplement use (no data on dose) was available only in 1986, and therefore this information was not updated. Analyses of calcium and magnesium supplementation using the 1986 data only were also conducted to be comparable to the analyses of potassium supplements. Height was ascertained in 1976. Data on usual aspirin use were updated in 1982, 1984, and 1988, and those on alcohol intake were updated in 1984, 1986, and 1990. All other exposure variables (ie, body mass index; menopausal status; postmenopausal hormone use; histories of hypertension, diabetes, and high cholesterol levels; and the use of multivitamins and vitamin E supplements) were updated on each follow-up questionnaire.
The relative risk of stroke was defined as the incidence rate of stroke
among women in various categories for intake of nutrients and foods
divided by the corresponding rate among the women in the lowest
category of intake. We calculated relative risks with 95% CIs,
adjusted for age in 5-year categories and for smoking status in 5
categories (never, former, current 1 to 14/d, current 15 to 24/d, and
current 25/d), and tested for linear trend across the dietary
categories using median variables of each dietary category. To
adjust simultaneously for other
cardiovascular risk factors, we used pooled logistic
regression over the seven 2-year intervals.33 In
multivariate models, potassium and magnesium intakes
were not entered into models simultaneously because these 2
variables were highly correlated (r=0.83). The
correlations between calcium and potassium intake (r=0.55)
and between calcium and magnesium intake (r=0.46) were more
moderate.
|
Results |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
Among 85 764 women followed for 14 years, we documented 690 incident cases of stroke during 1 164 674 person-years of follow-up. Stroke cases consisted of 129 subarachnoid hemorrhages, 74 intraparenchymal hemorrhages, 386 ischemic strokes, and 101 strokes of undetermined type. Calcium intake was positively associated with history of diabetes, vigorous exercise, use of multivitamin and vitamin E supplements, and intakes of
-3
polyunsaturated fatty acids and animal protein and was inversely
associated with smoking, hypertension, and intakes of alcohol and
saturated fat. Intakes of potassium and magnesium had associations with
these variables similar to those for calcium intake, except for
weak positive correlations with smoking (Table 1
).
|
Table 2 presents age- and
smoking-adjusted risk of ischemic stroke according to quintiles
of calcium intake (including calcium from multivitamin supplements but
not specific calcium supplements), dietary potassium, and dietary
magnesium intake. Calcium intake was inversely associated with risk of
ischemic stroke, and the association was stronger when we
excluded nonatherogenic embolic infarctions (n=39). A reduction in risk
was found in the second quintile, and further small reductions were
observed in higher quintiles, but there was no strong linear trend.
There was no clear relation between calcium intake and risk of
subarachnoid hemorrhage, but a suggestion of a
decreased risk of intraparenchymal hemorrhage was noted.
Intakes of potassium and magnesium were not related to risk of
intraparenchymal hemorrhage or subarachnoid
hemorrhage.
|
|
Table 3 shows
multivariate adjusted relative risks of
ischemic stroke (excluding nonatherogenic embolic infarctions)
according to quintile of calcium, potassium, and magnesium intakes. The
inverse association between calcium intake remained statistically
significant after adjustment for history of hypertension and after
further adjustment for other cardiovascular risk
factors. Further adjustment for potassium or magnesium intake
attenuated the association slightly. The inverse association between
potassium intake and risk was attenuated after adjustment for history
of hypertension and other cardiovascular risk factors.
Further adjustment for calcium intake, however, substantially
attenuated the association, which was no longer statistically
significant. The inverse association with magnesium intake also was no
longer significant after adjustment for history of hypertension. The
trend for reduction in risk of intraparenchymal hemorrhage
associated with calcium intake remained statistically nonsignificant
after multivariate adjustment for
cardiovascular risk factors; the
multivariate relative risk in the highest versus lowest
quintiles of calcium intake was 0.62 (95% CI, 0.27 to 1.39;
P for trend=0.11).
|
There was no clear dose-response association between calcium supplement
use and stroke risk, but women who took supplements containing 400
mg/d tended to have lower risk: the multivariate
relative risk adjusted for age, smoking, other
cardiovascular risk factors, and dietary calcium was
0.88 (95% CI, 0.66 to 1.18; P=0.39) when we compared
calcium supplement users with nonusers (updated information).
The multivariate relative risk based on the 1986 data
only was 0.75 (95% CI, 0.56 to 1.01; P=0.05) for calcium
supplement users compared with nonusers. Potassium
supplementation was not associated with risk of ischemic
stroke; the multivariate relative risk was 1.03 (95%
CI, 0.63 to 1.68; P=0.91). We observed no reduction in risk
of ischemic stroke among magnesium supplement users with or
without updating of use; the multivariate relative risk
was 1.47 (95% CI, 0.73 to 2.93; P=0.28) with updating and
1.46 (95% CI, 0.76 to 2.81; P=0.26) without updating.
Dietary calcium intake (excluding multivitamin supplements) was also
inversely associated with the risk of ischemic stroke (Table 4). The inverse association was stronger
for dairy calcium than for nondairy calcium, but the CIs broadly
overlapped. The age- and smoking-adjusted relative risk of
ischemic stroke in the highest versus the lowest quintile was
0.68 (95% CI, 0.50 to 0.94) for dairy calcium (P for
trend=0.05) and 0.82 (95% CI, 0.58 to 1.16) for nondairy
calcium (P for trend=0.08). Further
adjustment for other cardiovascular risk factors
attenuated the associations, but they continued to be stronger for
dairy than for nondairy calcium.
|
We further explored the relation between specific food sources of dairy
calcium and the risk of ischemic stroke. We observed an inverse
relation between yogurt intake and the age- and smoking-adjusted risk
of ischemic stroke; the relative risk among women who ate
yogurt 5 times per week compared with those who almost never ate it
was 0.69 (95% CI, 0.34 to 1.40; P for trend=0.06). Similar
inverse trends were seen for hard cheese (the relative risk compared
with women who almost never ate it was 0.63 [95% CI, 0.40 to 0.99]
for women who ate cheese 1 times per day; P for
trend=0.20), ice cream (0.70 [95% CI, 0.42 to 1.17] for women who
ate 5 times per week; P for trend=0.14), and milk (0.74
[95% CI, 0.51 to 1.06] for women who ate 2 times per day;
P for trend=0.44), but less so for cottage cheese (0.94
[95% CI, 0.60 to 1.47] for women who ate 5 times per week;
P for trend=0.71).
|
Discussion |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
We observed that intakes of calcium, potassium, and magnesium were each inversely associated with the age- and smoking-adjusted risk of ischemic stroke, excluding embolic infarction of nonatherogenic origin. After adjustment for history of hypertension and other cardiovascular risk factors, the association with calcium remained statistically significant, and that with potassium was of borderline significance. Further simultaneous adjustment of calcium and potassium intake more strongly supported an independent association of ischemic stroke with calcium intake.
A prospective study of Japanese Americans living in Honolulu, Hawaii,
showed an inverse relation between calcium intake and risk of
ischemic stroke,20 an association restricted to
dairy calcium intake and specifically to milk consumption. In our
study, however, the inverse association with dairy calcium intake was
not restricted to milk but was also observed for yogurt, hard cheese,
and ice cream. This discrepancy is not surprising because milk is a
dominant source of dairy calcium for Japanese Americans, but in the
present study population, milk accounted for 60% of dairy
calcium, and yogurt, cheese, and ice cream accounted for 40%.
Median intake of calcium was 406 mg/d for the Japanese-American
men20 and 675 mg/d for our population of women, with dairy
calcium accounting for most of the difference between the 2
populations.
The present study also suggested an inverse association between
nondairy calcium intake and risk of ischemic stroke, although
the relation was not as strong as for dairy calcium, perhaps in part
because of the smaller range of calcium intake from nondairy (a 3-fold
difference in medians of extreme quintiles) compared with dairy foods
(a 10-fold difference) (Table 4
). The weaker association may
also be due to lower bioavailability of nondairy calcium than dairy
calcium.34 The relation between calcium supplements and
reduced risk of ischemic stroke was stronger when the
variable of calcium supplementation was not updated, suggesting a
long-term protective effect of calcium supplementation on
ischemic stroke. These results suggest that calcium intake per
se may reduce risk of ischemic stroke.
The mechanisms by which calcium intake could reduce risk of ischemic stroke are not well elucidated. A recent meta-analysis of randomized clinical trials concludes that calcium supplementation may slightly reduce systolic blood pressure, by -0.9 to -1.3 mm Hg, but not diastolic blood pressure.6 7 In the Nurses' Health Study,2 dietary calcium estimated from the 1980 dietary questionnaire had an independent and significant inverse association with risk of development of hypertension during 1980–1984. However, the analysis of dietary calcium and risk of hypertension during 1984–1988 using the 1984 dietary questionnaire did not yield a significant association.29 These results suggest that a hypotensive effect of calcium intake, if any, is small and unlikely to explain any substantial part of the inverse relation between calcium intake and risk of ischemic stroke. This interpretation is supported by our finding that the inverse association was only slightly attenuated in multivariate analyses after adjustment for history of hypertension. In addition to a hypotensive effect, increased calcium intake reduced platelet aggregation in animal and human studies,35 36 providing another mechanism that may lead to reduction of risk of ischemic stroke. In animal studies35 37 and human trials of hypercholesterolemic persons,38 39 calcium supplementation has reduced serum total cholesterol, which may also contribute to reduce the risk of ischemic stroke.40
Dietary potassium intake also was associated with reduced risk of ischemic stroke, but the relation was far from statistically significant after simultaneous adjustment for calcium intake. However, we cannot rule out a modest independent effect of dietary potassium on risk. We found no association between potassium supplement use and risk of ischemic stroke. A meta-analysis of randomized clinical trials found that potassium supplementation reduces both systolic (-5.9 mm Hg) and diastolic blood pressure (-3.4 mm Hg).8 Hypertensive rats given a high-potassium diet had decreased vascular smooth muscle cell proliferation that may contribute to a reduced risk of stroke.16 A prospective study of American white men and women showed a significant inverse association between potassium intake and stroke-associated mortality.21 However, the number of end points was small (n=24) and relied solely on the death certificate diagnoses, which did not allow analyses of specific stroke subtype. A study of Japanese persons living in Honolulu showed an inverse association between potassium intake and risk of fatal ischemic stroke (n=33), but not of nonfatal ischemic stroke (n=221).22 A recent study of US health professional men indicated an inverse association between potassium intake and risk of all stroke and ischemic stroke, particularly among hypertensive men.23
As in the study of US men,23 in the present study we found no independent association between magnesium intake and risk of stroke, but we cannot exclude a modest effect of this cation on risk of ischemic stroke. A weak inverse trend was found in the age- and smoking-adjusted analysis. Attenuation of the association after further adjustment for history of hypertension was consistent with the finding that magnesium intake was associated with reduced risk of development of hypertension in this cohort.2 Several randomized trials have tested whether magnesium supplementation reduces blood pressure, but the results have been inconsistent.3 9 10
In conclusion, dietary intake of calcium was inversely associated with
risk of ischemic stroke in middle-aged American women. The
shape of this inverse association was not log linear; the increase in
risk was limited to the lowest quintile of intake, and intakes >600
mg/d did not appear to reduce risk of stroke further. Although the
mechanisms to account for this relation are not clear, the present
study suggests that avoiding low intakes of calcium and possibly
potassium may be beneficial for prevention of ischemic stroke.
However, it also remains possible that women in the lowest quintile of
calcium intake had unknown characteristics that made them susceptible
to ischemic stroke. Further studies of intake of cations and
risk of stroke are warranted.
|
Acknowledgments |
|---|
This study was supported by research grants CA40356 and HL34594 from the National Institutes of Health. Dr Iso is the recipient of an overseas research fellowship from Japan Society for the Promotion of Science. The authors are indebted to the participants in the Nurses' Health Study for their continuing cooperation and to Leiming Li, Mark Shneyder, Karen Corsano, Barbara Egan, and Lisa Dunn for their expert help.
Received March 24, 1999; revision received May 19, 1999; accepted June 2, 1999.
|
References |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
1. Cappuccio FP, Elliot P, Allender PS, Pryer J, Follman DA, Cutler JA. Epidemiologic association between dietary calcium intake and blood pressure: a meta-analysis of published data. Am J Epidemiol. 1995;142:935–945.
2.
Witteman JCM, Willett WC, Stampfer MJ, Colditz GA,
Sacks FM, Speizer FE, Rosner B, Hennekens CH. A prospective study of
nutritional factors and hypertension among US women.
Circulation. 1989;80:1320–1327.
3.
The Trials of Hypertension Prevention Collaborative
Research Group. The effects of nonpharmacologic intervention on blood
pressure of persons with high normal levels. JAMA. 1992;267:1213–1220.
4.
Joffres MR, Reed DM, Yano K. Relationship of magnesium
intake and other dietary factors to blood pressure: the Honolulu Heart
Study. Am J Clin Nutr. 1987;45:469–475.
5.
Ascherio A, Rimm EB, Giovannucci EL, Colditz GA,
Rosner B, Willett WC, Sacks F, Stampfer MJ. A prospective study of
nutritional factors and hypertension among US men.
Circulation. 1992;86:1475–1484.
6.
Bucher HC, Cook RJ, Guyatt GH, Lang JD, Cook DJ,
Hatala R, Hunt DL. Effects of dietary calcium supplementation on blood
pressure: a meta-analysis of randomized controlled trials.
JAMA. 1996;275:1016–1022.
7.
Allender PS, Cutler JA, Follmann D, Cappuccio FP,
Pryer J, Elliot P. Dietary calcium and blood pressure: a
meta-analysis of randomized clinical trials. Ann Intern
Med. 1996;124:825–831.
8. Cappuccio EP, MacGregor GA. Does potassium supplementation lower blood pressure? A meta-analysis of published trials. J Hypertens. 1991;9:465–473.[Medline] [Order article via Infotrieve]
9. Dychner T, Wester PO. Effect of magnesium on blood pressure. BMJ. 1983;286:1847–1849.
10. Cappuccino FP, Markandu ND, Beynon GW, Shore AC, Sampson B, MacGregor GA. Lack of effect of oral magnesium on high blood pressure: a double blind study. BMJ. 1985;291:235–238.
11.
Wolf PA. Risk factors for stroke. Stroke. 1985;16:359–360.
12. Ayachi S. Increased dietary calcium lowers blood pressure in the spontaneous hypertensive rat. Metabolism. 1979;28:1234–1238.[Medline] [Order article via Infotrieve]
13. Workman ML, Paller MS. Cardiovascular and endocrine effects of potassium in spontaneously hypertensive rats. Am J Physiol. 1985;249(pt 2):H907–H913.
14. Berthelot A, Esposito J. Effects of dietary magnesium on the development of hypertension in spontaneously hypertensive rat. J Am Coll Nutr. 1983;4:343–353.
15.
Stern N, Lee DBN, Solis V, Lee DB, Silis V, Beck FW,
Deftos L, Manolagas SC, Sowers JR. Effects of high calcium intake on
blood pressure and calcium metabolism in young SHR.
Hypertension. 1984;6:639–646.
16. Tobian L. High-potassium diets markedly protect against stroke deaths and kidney diseases in hypertensive rats, an echo from prehistoric days. J Hypertens. 1986;4(suppl 4):S67–S76.
17.
Overlack A, Zenzen JG, Ressel C, Muller HM, Stumpe KO.
Influence of magnesium on blood pressure and the effect of
nifedipine in rats. Hypertension. 1987;9:139–143.
18. Ganguli M, Tobin L, Sugimto T. High magnesium diets increase blood pressure and enhance stroke mortality in hypertensive SHRsp rats. Am J Hypertens. 1989;2:780–783.[Medline] [Order article via Infotrieve]
19.
Peuler JD, Schelper RL. Partial protection from
salt-induced stroke and mortality by high oral calcium in hypertensive
rats. Stroke. 1992;23:532–538.
20.
Abbott RD, Curb D, Rodriguez BL, Sharp DS, Burchfiel
CM, Yano K. Effects of dietary calcium and milk consumption on risk of
thromboembolic stroke in older middle-aged men: the Honolulu Heart
Program. Stroke. 1996;27:813–818.
21. Khaw K-T, Barrett-Connor E. Dietary potassium and stroke-associated mortality: a 12-year prospective population study. N Engl J Med. 1987;316:235–240.[Abstract]
22. Lee CN, Reed DM, MacLean CJ, Yano K, Chiu D. Dietary potassium and stroke. N Engl J Med. 1988;318:995–996.[Medline] [Order article via Infotrieve]
23.
Ascherio A, Rimm EB, Hernan MA, Giovannucci EL, Kawachi
I, Stampfer MJ, Willett WC. Intake of potassium, calcium, and fiber and
risk of stroke among US men. Circulation. 1998;98:1198–1204.
24. Stampfer MJ, Willett WC, Colditz GA, Rosner BA, Speizer FE, Hennekens CH. A prospective study of postmenopausal estrogen therapy and coronary heart disease. N Engl J Med. 1985;313:1044–1049.[Abstract]
25.
Willett WC, Sampson L, Stampfer MJ, Rosner B, Bain C,
Witschi J, Hennekens CH, Speizer FE. Reproducibility and validity of a
semiquantitative food frequency questionnaire. Am J
Epidemiol. 1985;122:51–65.
26.
Willett WC, Stampfer MJ. Total energy intake:
implications for epidemiologic analyses. Am J
Epidemiol. 1986;124:17–27.
27.
Willett WC, Sampson L, Browne ML, Stampfer MJ, Rosner
B, Hennekens CH, Speizer FE. The use of a self-administered
questionnaire to assess diet four years in the past. Am J
Epidemiol. 1988;127:188–199.
28.
Salvini S, Hunter DJ, Sampson L, Stampfer MJ,
Colditz GA, Rosner B, Willett WC. Food-based validation of a dietary
questionnaire: the effects of week-to-week variation in food
consumption. Int J Epidemiol. 1989;18:858–867.
29.
Ascherio A, Hennekens C, Willett WC, Sacks F,
Rosner B, Manson J, Witteman J, Stampfer MJ. Prospective study of
nutritional factors, blood pressure, and hypertension among US women.
Hypertension. 1996;27:1065–1072.
30.
Stampfer MJ, Willett WC, Speizer FE, Dysert DC, Lipnick
R, Rosner B, Hennekens CH. Test of the National Death Index.
Am J Epidemiol. 1984;119:837–839.
31. Walker AE, Robins M, Weinfeld FD. The National Survey of Stroke: clinical findings. Stroke. 1981;119:837–839.
32. Benjamin EJ, Levy D, Vaziri SM, D'Agostino RB, Belanger AJ, Wolf PA. Independent risk factors for atrial fibrillation in a population-based cohort: the Framingham Heart Study. JAMA. 1994;27:840–844.
33. D'Agostino RB, Lee M-L, Belanger AJ, Cupples LA, Anderson K, Kannel WB. Relation of pooled logistic regression to time dependent cox regression analysis: the Framingham Heart Study. Stat Med. 1990;9:1501–1515.[Medline] [Order article via Infotrieve]
34. Miller DD. Calcium in the diet: food sources, recommended intake, and nutritional bioavailability. Adv Food Nutr Res. 1989;33:103–156.[Medline] [Order article via Infotrieve]
35. Renaud S, Ciavatti M, Theveron C, Ripoll JP. Protective effects of dietary calcium and magnesium on platelet function and atherosclerosis in rabbits fed saturated fat. Atherosclerosis.. 1983;47:187–198.[Medline] [Order article via Infotrieve]
36. Renaud S, Morazain R, Godsey F, Dumont E, Thevenon C, Matrin JL, Mendy F. Nutrients, platelet function and composition in nine groups of French and British farmers. Atherosclerosis. 1986;60:37–48.[Medline] [Order article via Infotrieve]
37. Takur CP, Jha AN. Influence of milk, yogurt and calcium on cholesterol-induced atherosclerosis in rabbits. Atherosclerosis. 1981;39:211–215.[Medline] [Order article via Infotrieve]
38. Carlson LA, Olsson AG, Oro L, Rossner S. Effect of oral calcium upon serum cholesterol and triglycerides in patient with hyperlipidemia. Atherosclerosis. 1971;14:391–400.[Medline] [Order article via Infotrieve]
39.
Karanja N, Morris CD, Illingworth DR, McCarron DA.
Plasma lipids and hypertension: response to calcium supplementation.
Am J Clin Nutr. 1987;45:60–65.
40.
Hebert PR, Gaziano JM, Chan KS, Hennekens CH.
Cholesterol lowering with statin drugs, risk of stroke, and
total mortality: an overview of randomized trials. JAMA. 1997;278:313–321.
This article has been cited by other articles:
 |
|
 |
|
  J. R. Romero, P. M. Ridker, and R. Y.L. Zee Gene Variation of the Transient Receptor Potential Cation Channel, Subfamily M, Member 7 (TRPM7), and Risk of Incident Ischemic Stroke: Prospective, Nested, Case-Control Study Stroke, September 1, 2009; 40(9): 2965 - 2968. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Ohira, J. M. Peacock, H. Iso, L. E. Chambless, W. D. Rosamond, and A. R. Folsom Serum and Dietary Magnesium and Risk of Ischemic Stroke: The Atherosclerosis Risk in Communities Study Am. J. Epidemiol., June 15, 2009; 169(12): 1437 - 1444. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Z. LaCroix, J. Kotchen, G. Anderson, R. Brzyski, J. A. Cauley, S. R. Cummings, M. Gass, K. C. Johnson, M. Ko, J. Larson, et al. Calcium Plus Vitamin D Supplementation and Mortality in Postmenopausal Women: The Women's Health Initiative Calcium-Vitamin D Randomized Controlled Trial J Gerontol A Biol Sci Med Sci, May 1, 2009; 64A(5): 559 - 567. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. R. Cook, E. Obarzanek, J. A. Cutler, J. E. Buring, K. M. Rexrode, S. K. Kumanyika, L. J. Appel, P. K. Whelton, and for the Trials of Hypertension Prevention Collabor Joint Effects of Sodium and Potassium Intake on Subsequent Cardiovascular Disease: The Trials of Hypertension Prevention Follow-up Study Arch Intern Med, January 12, 2009; 169(1): 32 - 40. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. C. Elwood, D. I. Givens, A. D. Beswick, A. M. Fehily, J. E. Pickering, and J. Gallacher The Survival Advantage of Milk and Dairy Consumption: an Overview of Evidence from Cohort Studies of Vascular Diseases, Diabetes and Cancer J. Am. Coll. Nutr., December 1, 2008; 27(6): 723S - 734S. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Lamarche Review of the Effect of Dairy Products on Non-Lipid Risk Factors for Cardiovascular Disease J. Am. Coll. Nutr., December 1, 2008; 27(6): 741S - 746S. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Umesawa, H. Iso, J. Ishihara, I. Saito, Y. Kokubo, M. Inoue, S. Tsugane, and for the JPHC Study Group Dietary Calcium Intake and Risks of Stroke, Its Subtypes, and Coronary Heart Disease in Japanese: The JPHC Study Cohort I Stroke, September 1, 2008; 39(9): 2449 - 2456. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Ovbiagele, S. Starkman, P. Teal, P. Lyden, M. Kaste, S. M. Davis, W. Hacke, M. Fierus, J. L. Saver, and on behalf of the VISTA Investigators Serum Calcium as Prognosticator in Ischemic Stroke Stroke, August 1, 2008; 39(8): 2231 - 2236. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Umesawa, H. Iso, C. Date, A. Yamamoto, H. Toyoshima, Y. Watanabe, S. Kikuchi, A. Koizumi, T. Kondo, Y. Inaba, et al. Relations between dietary sodium and potassium intakes and mortality from cardiovascular disease: the Japan Collaborative Cohort Study for Evaluation of Cancer Risks Am. J. Clinical Nutrition, July 1, 2008; 88(1): 195 - 202. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. C. Larsson, M. J. Virtanen, M. Mars, S. Mannisto, P. Pietinen, D. Albanes, and J. Virtamo Magnesium, Calcium, Potassium, and Sodium Intakes and Risk of Stroke in Male Smokers Arch Intern Med, March 10, 2008; 168(5): 459 - 465. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. J Bolland, P A. Barber, R. N Doughty, B. Mason, A. Horne, R. Ames, G. D Gamble, A. Grey, and I. R Reid Vascular events in healthy older women receiving calcium supplementation: randomised controlled trial BMJ, February 2, 2008; 336(7638): 262 - 266. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. D. Sturgeon, A. R. Folsom, W.T. Longstreth Jr, E. Shahar, W. D. Rosamond, and M. Cushman Risk Factors for Intracerebral Hemorrhage in a Pooled Prospective Study Stroke, October 1, 2007; 38(10): 2718 - 2725. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. H. Buck, D. S. Liebeskind, J. L. Saver, O. Y. Bang, S. Starkman, L. K. Ali, D. Kim, J. P. Villablanca, N. Salamon, S. W. Yun, et al. Association of Higher Serum Calcium Levels With Smaller Infarct Volumes in Acute Ischemic Stroke Arch Neurol, September 1, 2007; 64(9): 1287 - 1291. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. M. Klevay, J. D. Bogden, M. Aladjem, H. H. Sandstead, F. W. Kemp, W. Li, J. Skurnick, and A. Aviv Renal And Gastrointestinal Potassium Excretion In Humans: New Insight Based On New Data And Review And Analysis Of Published Studies J. Am. Coll. Nutr., April 1, 2007; 26(2): 103 - 110. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. K. Lorenzen, S. Nielsen, J. J. Holst, I. Tetens, J. F. Rehfeld, and A. Astrup Effect of dairy calcium or supplementary calcium intake on postprandial fat metabolism, appetite, and subsequent energy intake Am. J. Clinical Nutrition, March 1, 2007; 85(3): 678 - 687. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Jauhiainen and R. Korpela Milk Peptides and Blood Pressure J. Nutr., March 1, 2007; 137(3): 825S - 829S. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Umesawa, H. Iso, C. Date, A. Yamamoto, H. Toyoshima, Y. Watanabe, S. Kikuchi, A. Koizumi, T. Kondo, Y. Inaba, et al. Dietary Intake of Calcium in Relation to Mortality From Cardiovascular Disease: The JACC Study Stroke, January 1, 2006; 37(1): 20 - 26. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Alonso, J. J. Beunza, M. Delgado-Rodriguez, J A. Martinez, and M. A. Martinez-Gonzalez Low-fat dairy consumption and reduced risk of hypertension: the Seguimiento Universidad de Navarra (SUN) cohort Am. J. Clinical Nutrition, November 1, 2005; 82(5): 972 - 979. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Kimura, X. Cao, and A. Aviv Calcium adaptation to sodium pump inhibition in a human megakaryocytic cell line Am J Physiol Cell Physiol, October 1, 2005; 289(4): C891 - C897. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Azadbakht, P. Mirmiran, A. Esmaillzadeh, and F. Azizi Dairy consumption is inversely associated with the prevalence of the metabolic syndrome in Tehranian adults Am. J. Clinical Nutrition, September 1, 2005; 82(3): 523 - 530. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P C Elwood, J J Strain, P. J Robson, A. M Fehily, J. Hughes, J. Pickering, and A. Ness Milk consumption, stroke, and heart attack risk: evidence from the Caerphilly cohort of older men J Epidemiol Community Health, June 1, 2005; 59(6): 502 - 505. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. K. Choi, W. C. Willett, M. J. Stampfer, E. Rimm, and F. B. Hu Dairy Consumption and Risk of Type 2 Diabetes Mellitus in Men: A Prospective Study Arch Intern Med, May 9, 2005; 165(9): 997 - 1003. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Amighi, S. Sabeti, O. Schlager, W. Mlekusch, M. Exner, W. Lalouschek, R. Ahmadi, E. Minar, and M. Schillinger Low Serum Magnesium Predicts Neurological Events in Patients With Advanced Atherosclerosis Stroke, January 1, 2004; 35(1): 22 - 27. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Fraser Commentary: Protection from stroke by eating animal foods? Surely not! Int. J. Epidemiol., August 1, 2003; 32(4): 543 - 545. [Full Text] [PDF]
|
|
|
|
|
|
M.J. Ariesen, S.P. Claus, G.J.E. Rinkel, and A. Algra Risk Factors for Intracerebral Hemorrhage in the General Population: A Systematic Review Stroke, August 1, 2003; 34(8): 2060 - 2065. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. R. Levine and B. M. Coull Potassium depletion as a risk factor for stroke: Will a banana a day keep your stroke away? Neurology, August 13, 2002; 59(3): 302 - 303. [Full Text] [PDF]
|
|
|
|
|
|
D. M. Green, A. H. Ropper, R. A. Kronmal, B. M. Psaty, and G. L. Burke Serum potassium level and dietary potassium intake as risk factors for stroke Neurology, August 13, 2002; 59(3): 314 - 320. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. A. Pereira, D. R. Jacobs Jr, L. Van Horn, M. L. Slattery, A. I. Kartashov, and D. S. Ludwig Dairy Consumption, Obesity, and the Insulin Resistance Syndrome in Young Adults: The CARDIA Study JAMA, April 24, 2002; 287(16): 2081 - 2089. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. J He and G. A MacGregor Blood pressure and stroke; the PROGRESS trial Journal of Renin-Angiotensin-Aldosterone System, September 1, 2001; 2(3): 153 - 155. [PDF]
|
|
|
|
|
|
F. J He and G. A MacGregor Fortnightly review: Beneficial effects of potassium BMJ, September 1, 2001; 323(7311): 497 - 501. [Full Text] [PDF]
|
|
|
|
|
|
L. K. Massey Dairy Food Consumption, Blood Pressure and Stroke J. Nutr., July 1, 2001; 131(7): 1875 - 1878. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. D. Miller, J. K. Jarvis, and L. D. McBean The Importance of Meeting Calcium Needs with Foods J. Am. Coll. Nutr., April 1, 2001; 20(2): 168S - 185. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Yokoyama, C. Date, Y. Kokubo, N. Yoshiike, Y. Matsumura, and H. Tanaka Serum Vitamin C Concentration Was Inversely Associated With Subsequent 20-Year Incidence of Stroke in a Japanese Rural Community : The Shibata Study Stroke, October 1, 2000; 31(10): 2287 - 2294. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. M Weaver Calcium requirements of physically active people Am. J. Clinical Nutrition, August 1, 2000; 72(2): 579S - 584. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||