Migraine-Associated Common Genetic Variants Confer Greater Risk of Posterior vs. Anterior Circulation Ischemic Stroke☆

OBJECTIVE

To examine potential genetic relationships between migraine and the two distinct phenotypes posterior circulation ischemic stroke (PCiS) and anterior circulation ischemic stroke (ACiS), we generated migraine polygenic risk scores (PRSs) and compared these between PCiS and ACiS, and separately vs. non-stroke control subjects.

METHODS

Acute ischemic stroke cases were classified as PCiS or ACiS based on lesion location on diffusion-weighted MRI. Exclusion criteria were lesions in both vascular territories or uncertain territory; supratentorial PCiS with ipsilateral fetal posterior cerebral artery; and cases with atrial fibrillation. We generated migraine PRS for three migraine phenotypes (any migraine; migraine without aura; migraine with aura) using publicly available GWAS data and compared mean PRSs separately for PCiS and ACiS vs. non-stroke control subjects, and between each stroke phenotype.

RESULTS

Our primary analyses included 464 PCiS and 1079 ACiS patients with genetic European ancestry. Compared to non-stroke control subjects (n=15396), PRSs of any migraine were associated with increased risk of PCiS (p=0.01-0.03) and decreased risk of ACiS (p=0.010-0.039). Migraine without aura PRSs were significantly associated with PCiS (p=0.008-0.028), but not with ACiS. When comparing PCiS vs. ACiS directly, migraine PRSs were higher in PCiS vs. ACiS for any migraine (p=0.001-0.010) and migraine without aura (p=0.032-0.048). Migraine with aura PRS did not show a differential association in our analyses.

CONCLUSIONS

Our results suggest a stronger genetic overlap between unspecified migraine and migraine without aura with PCiS compared to ACiS. Possible shared mechanisms include dysregulation of cerebral vessel endothelial function.

Detailed phenotyping of posterior vs. anterior circulation ischemic stroke: a multi-center MRI study

OBJECTIVE

Posterior circulation ischemic stroke (PCiS) constitutes 20-30% of ischemic stroke cases. Detailed information about differences between PCiS and anterior circulation ischemic stroke (ACiS) remains scarce. Such information might guide clinical decision making and prevention strategies. We studied risk factors and ischemic stroke subtypes in PCiS vs. ACiS and lesion location on magnetic resonance imaging (MRI) in PCiS.

METHODS

Out of 3,301 MRIs from 12 sites in the National Institute of Neurological Disorders and Stroke (NINDS) Stroke Genetics Network (SiGN), we included 2,381 cases with acute DWI lesions. The definition of ACiS or PCiS was based on lesion location. We compared the groups using Chi-squared and logistic regression.

RESULTS

PCiS occurred in 718 (30%) patients and ACiS in 1663 (70%). Diabetes and male sex were more common in PCiS vs. ACiS (diabetes 27% vs. 23%, p < 0.05; male sex 68% vs. 58%, p < 0.001). Both were independently associated with PCiS (diabetes, OR = 1.29; 95% CI 1.04-1.61; male sex, OR = 1.46; 95% CI 1.21-1.78). ACiS more commonly had large artery atherosclerosis (25% vs. 20%, p < 0.01) and cardioembolic mechanisms (17% vs. 11%, p < 0.001) compared to PCiS. Small artery occlusion was more common in PCiS vs. ACiS (20% vs. 14%, p < 0.001). Small artery occlusion accounted for 47% of solitary brainstem infarctions.

CONCLUSION

Ischemic stroke subtypes differ between the two phenotypes. Diabetes and male sex have a stronger association with PCiS than ACiS. Definitive MRI-based PCiS diagnosis aids etiological investigation and contributes additional insights into specific risk factors and mechanisms of injury in PCiS.

Carotid Bulb Webs as a Cause of "Cryptogenic" Ischemic Stroke

BACKGROUND AND PURPOSE

Carotid webs are intraluminal shelf-like filling defects at the carotid bulb with recently recognized implications in patients with recurrent ischemic stroke. We sought to determine whether carotid webs are an under-recognized cause of "cryptogenic" ischemic stroke and to estimate their prevalence in the general population.

MATERIALS AND METHODS

A retrospective review of neck CTA studies in young patients with cryptogenic stroke over the past 6 years (n = 33) was performed to determine the prevalence of carotid webs compared with a control group of patients who received neck CTA studies for reasons other than ischemic stroke (n = 63).

RESULTS

The prevalence of carotid webs in the cryptogenic stroke population was 21.2% (95% CI, 8.9%-38.9%). Patients with symptomatic carotid webs had a mean age of 38.9 years (range, 30-48 years) and were mostly African American (86%) and women (86%). In contrast, only 1.6% (95% CI, 0%-8.5%) of patients in the control group demonstrated a web. Our findings demonstrate a statistically significant association between carotid webs and ischemic stroke (OR = 16.7; 95% CI, 2.78-320.3; P = .01).

CONCLUSIONS

Carotid webs exhibit a strong association with ischemic stroke, and their presence should be suspected in patients lacking other risk factors, particularly African American women.

Heritability of young- and old-onset ischaemic stroke

BACKGROUND AND PURPOSE

Although the genetic contribution to stroke risk is well known, it remains unclear if young-onset stroke has a stronger genetic contribution than old-onset stroke. This study aims to compare the heritability of ischaemic stroke risk between young and old, using common genetic variants from whole-genome array data in population-based samples.

METHODS

This analysis included 4050 ischaemic stroke cases and 5765 controls from six study populations of European ancestry; 47% of cases were young-onset stroke (age < 55 years). To quantify the heritability for stroke risk in these unrelated individuals, the pairwise genetic relatedness was estimated between individuals based on their whole-genome array data using a mixed linear model. Heritability was estimated separately for young-onset stroke and old-onset stroke (age ≥ 55 years).

RESULTS

Heritabilities for young-onset stroke and old-onset stroke were estimated at 42% (±8%, P < 0.001) and 34% (±10%, P < 0.001), respectively.

CONCLUSIONS

Our data suggest that the genetic contribution to the risk of stroke may be higher in young-onset ischaemic stroke, although the difference was not statistically significant.

Racial/ethnic disparities in mortality by stroke subtype in the United States, 1995-1998

Healthy People 2010 objectives for improving health include a goal to eliminate racial disparities in stroke mortality. Age-specific death rates by stroke subtype are not well documented among racial/ethnic minority populations in the United States. This report examines mortality rates by race/ethnicity for three stroke subtypes during 1995-1998. National Vital Statistics' death certificate data were used to calculate death rates for ischemic stroke (n = 507,256), intracerebral hemorrhage (n = 97,709), and subarachnoid hemorrhage (n = 27,334) among Hispanics, Blacks, American Indians/Alaska Natives, Asians/Pacific Islanders, and Whites by age and sex. Comparisons with Whites as the referent were made using age-standardized risk ratios and age-specific risk ratios. Age-standardized mortality rates for the three stroke subtypes were higher among Blacks than Whites. Death rates from intracerebral hemorrhage were also higher among Asians/Pacific Islanders than Whites. All minority populations had higher death rates from subarachnoid hemorrhage than did Whites. Among adults aged 25-44 years, Blacks and American Indians/Alaska Natives had higher risk ratios than did Whites for all three stroke subtypes. Increased public health attention is needed to reduce incidence and mortality for stroke, the third leading cause of death. Particular attention should be given to increasing awareness of stroke symptoms among young minority groups.

beta(2)-Glycoprotein 1-dependent anticardiolipin antibodies and risk of ischemic stroke and myocardial infarction: the honolulu heart program

BACKGROUND

It has been hypothesized that immunoreactivity to beta(2)-glycoprotein 1 (beta2GP1)-dependent anticardiolipin antibody (aCL), but not beta2GP1-independent aCL, is associated with increased risk of ischemic stroke and myocardial infarction (MI).

METHODS

We performed a nested case-control study examining aCL as a risk factor for ischemic stroke and MI by using stored frozen sera obtained from subjects enrolled in the Honolulu Heart Program and followed for up for 20 years. We measured beta2GP1-dependent and beta2GP1-independent aCL and anti-beta2GP1 immunoreactivity in 259 men who developed an ischemic stroke, in 374 men who developed an MI, and in a control group of 1360 men who remained free of both conditions.

RESULTS

Only beta2GP1-dependent aCL of the IgG class was significantly associated with both incident ischemic stroke and MI. This association was attenuated in the last 5 years of the 20-year follow-up. For stroke, the risk factor-adjusted relative odds for men with a positive versus a negative beta2GP1-dependent aCL of the IgG class were 2.2 (95% CI 1.5 to 3.4) at 15 years and 1.5 (95% CI 1.0 to 2.3) at 20 years. For MI, the adjusted relative odds were 1.8 (95% CI 1.2 to 2.6) at 15 years and 1.5 (95% CI 1.1 to 2.1) at 20 years.

CONCLUSIONS

These data suggest that aCL IgG, particularly the beta2GP1-dependent variety, is an important predictor of future stroke and MI in men.

Alcohol intake, type of beverage, and the risk of cerebral infarction in young women

BACKGROUND AND PURPOSE

The relationship between alcohol consumption and cerebral infarction remains uncertain, and few studies have investigated whether the relationship varies by alcohol type or is present in young adults. We examined the relationship between alcohol consumption, beverage type, and ischemic stroke in the Stroke Prevention in Young Women Study.

METHODS

All 59 hospitals in the greater Baltimore-Washington area participated in a population-based case-control study of stroke in young women. Case patients (n=224) were aged 15 to 44 years with a first cerebral infarction, and control subjects (n=392), identified by random-digit dialing, were frequency matched by age and region of residence. The interview assessed lifetime alcohol consumption and consumption and beverage type in the previous year, week, and day. ORs were obtained from logistic regression models controlling for age, race, education, and smoking status, with never drinkers as the referent.

RESULTS

Alcohol consumption, up to 24 g/d, in the past year was associated with fewer ischemic strokes (<12 g/d: OR 0.57, 95% CI 0. 38 to 0.86; 12 to 24 g/d: OR 0.38, 95% CI 0.17 to 0.86; >24 g/d: OR 0.95, 95% CI 0.43 to 2.10) in comparison to never drinking. Analyses of beverage type (beer, wine, liquor) indicated a protective effect for wine consumption in the previous year (<12 g/wk: OR 0.58, 95% CI 0.35 to 0.97; 12 g/wk to <12 g/d: OR 0.55, 95% CI 0.28 to 1.10; >/=12 g/d: OR 0.92, 95% CI 0.23 to 3.64).

CONCLUSIONS

Light to moderate alcohol consumption appears to be associated with a reduced risk of ischemic stroke in young women.

Clinical features of cardioembolic strokes identified by transesophageal echocardiography

Clinical and CT scan features predictive of a cardiac source of embolism (CSOE) are helpful in planning appropriate investigations in ischaemic strokes. The currently described predictors of CSOE were determined before the availability of trans esophageal echocardiography (TEE). After the advent of TEE, many new CSOE were discovered. The present study was planned to investigate if the previously described predictors of CSOE are also valid for patients with CSOE detectable only with TEE (TEE-detected CSOE). From 1992-1995, 485 consecutive patients of ischemic stroke were enrolled in the Maryland Stroke Data Bank (MSDB). Patients with CSOE identified only by TEE and not by clinical, electrocardiographic or transthoracic echocardiographic (TTE) examination were compared to patients with a CSOE with respect to the features of the history, neurologic examination and CT scan. Of 485 patients with cerebral infarction, 132 (27%) patients had CSOE. In 21/132 (16%), diagnosis of high risk CSOE could be established only by TEE. The most discriminating clinical findings in TEE-detected CSOE patients were visual field deficit (OR 2.9; 95% CI, 1.1-7.4) and neglect (OR 3.4; 95% CI,1.2-9.3). Less strong associations were also found with other clinical features described previously for CSOE. No significant differences were found for features of the initial CT scan. In summary, presence of visual field defect and hemineglect may suggest a higher likelihood of finding a CSOE by TEE, even if the clinical cardiac examination and TTE are normal.

Stroke in young adults: progress and opportunities

The epidemiology of stroke in young adults has been a relatively neglected area of study considering its relative prevalence in clinical practice; the relationship of oral contraceptive use, pregnancy, and migraine to stock risk; and the importance of prognosis when stroke occurs at a young age. In addition, stroke in your adult scan be used as a model system for understanding stroke incidence trends, the excess stroke risk experienced by African-American, and novel risk factors for stroke, including the genetic basis for stroke risk.

Lipoprotein (a) and the risk of ischemic stroke in young women

BACKGROUND AND PURPOSE

lipoprotein (a) (lp (a)) is a lipid-containing particle similar to LDL which has been found in atherosclerotic plaque. The role of lp (a) in ischemic stroke remains controversial, but some studies suggest lp (a) is particularly important as a risk factor for stroke in young adults. We investigated the role of lp (a) as a risk factor for stroke in young women enrolled in the Stroke Prevention in Young Women Study.

METHODS

subjects were participants in a population-based, case-control study of risk factors for ischemic stroke in young women. Cases were derived from surveillance of 59 regional hospitals in the central Maryland, Washington DC, Pennsylvania and Delaware area. Lp (a) was measured in 110 cases and 216 age-matched controls. Demographics, risk factors, and stroke subtype were determined by interview and review of medical records.

RESULTS

lp (a) values were higher in blacks than whites, but within racial groups, the distribution of lp (a) values was similar between cases and controls. After adjustment for age, race, hypertension, diabetes, cigarette smoking, coronary artery disease, total cholesterol and HDL cholesterol, the odds ratio for an association of lp (a) and stroke was 1.36 (95% CI 0.80-2.29). There was no dose-response relationship between lp (a) quintile and stroke risk. Among stroke subtypes, only lacunar stroke patients had significantly elevated lp (a) values compared to controls.

CONCLUSIONS

we found no association of lp (a) with stroke in a population of young women with ischemic stroke. Small numbers of patients limit conclusions regarding risk in ischemic stroke subtypes, but we could not confirm previous suggestions of an association of lp (a) with atherosclerotic stroke in young adults.

Oral contraceptives and stroke

Since 1962, more than 25 studies have been devoted to the relationship between oral contraceptives and stroke. They are all case-control or cohort epidemiological studies and thus contain the difficulties and biases that are inherent in these types of studies. The following conclusions can be drawn from these studies: High oestrogen content (> or = 50 microg) increases the risk of stroke, all stroke subtypes, and stroke death. Low oestrogen content (<50 microg) carries a very low or no risk of stroke. There are no data on progestogen only oral contraceptives. Stroke risk is greatly increased if associated risk factors are present, in particular hypertension, cigarette smoking and migraine. Oral contraceptives, even at low doses, significantly increase the risk of cerebral venous thrombosis, which is further enhanced if congenital thrombophilia is present. The attributable risk of stroke in young women using oral contraceptives is about 1 per 200000 woman-years. The contraceptive and non-contraceptive benefits of low dose oral contraceptives vastly outweigh their risks provided that other risk factors are absent or well controlled.

Migraine and stroke in young women

In this paper we review the evidence that migraine is associated with ischaemic stroke in young women, emphasizing potential biases, factors that may influence the association, potential mechanisms, and potential public health impact. Consistency of case-control findings from several countries and supporting evidence from prospective data suggest that the association is not an artifact of study design or execution, although, due to methodological limitations, none of the studies mentioned can be considered definite proof of the association. However, it is less clear whether migraine without aura is associated with stroke or whether the association is restricted to migraine with aura. Similarly, there are few data examining the magnitude of the association among nonusers of oral contraceptives compared with those who use low oestrogen oral contraceptives. As a consequence, there is a lack of data concurrently stratifying both by the presence vs. the absence of aura and by the use of low oestrogen oral contraceptives vs. non-use of oral contraceptives. Moreover, there is still no convincing evidence on the mechanisms that would be implied and on the groups of migraineurs really at risk of ischaemic stroke. Despite the considerable advances in our understanding of the relationship between migraine and stroke, there are many gaps in the data needed for public health recommendations.

Post-menopausal hormone replacement therapy and stroke risk

This paper will review available data bearing on the relationship of post-menopausal hormone replacement therapy to the risk of first or recurrent ischaemic stroke. Although experimental data from both human and animal studies will be briefly mentioned, the bulk of evidence is from observational epidemiological studies. As such, the limitations of observational studies, particularly as applied to the health effects of post-menopausal hormone replacement therapy, will be emphasized. We conclude that there is no compelling consistent evidence that post-menopausal hormone replacement therapy either decreases or increases stroke risk. There are, however, reasons to be concerned that this therapy may contribute to stroke risk.

Association between total homocyst(e)ine and the likelihood for a history of acute myocardial infarction by race and ethnicity: Results from the Third National Health and Nutrition Examination Survey

BACKGROUND

Few studies examining the association between total homocyst(e)ine and coronary heart disease have included blacks or Hispanics.

METHODS

Data from the third National Health and Nutrition Examination Survey (3173 patients), a nationally representative survey of US adults, were used to examine the relation between total homocyst(e)ine and an electrocardiogram or a physician's diagnosis of acute myocardial infarction (259 patients) among whites, blacks, and Mexican Americans >/=40 years old.

RESULTS

Vitamin B(12) and serum folate concentrations were significantly lower among persons with a total homocyst(e)ine concentration >/=15 micromol/L than among those with a total homocyst(e)ine concentration </=10 micromol/L. Persons with a total homocyst(e)ine concentration >/=15 micromol/L were also older and more likely to be hypertensive, have a higher cholesterol concentration, and smoke. Compared with persons with a total homocyst(e)ine concentration </=10 micromol/L, persons with a concentration >/=15 micromol/L had an odds ratio (OR) for myocardial infarction of 1.8 (95% confidence interval [CI], 1.2-2.9) after adjustment for cardiovascular disease risk factors. Similar associations were noted among whites (OR 1.8, 95% CI, 1.1-3.1) and blacks (OR 1.9, 95% CI, 0.8-4.2); a more modest association was noted among Mexican Americans (OR 1.2, 95% CI, 0.3-5.0). The association between total homocyst(e)ine and myocardial infarction was also more pronounced in persons without hypertension or diabetes.

CONCLUSIONS

Almost a 2-fold increased likelihood of myocardial infarction among persons with a total homocyst(e)ine concentration >/=15 micromol/L was noted in this nationally representative survey. The magnitude of the association did not differ by race or ethnicity.

Utilization of multiple imperfect assessments of the dependent variable in a logistic regression analysis

Often, in biomedical research, there are multiple sources of imperfect information regarding a dichotomous variable of interest. For example, in a study we are conducting on the relationship between cocaine use and stroke risk, information on the cocaine use of each study patient is available from three fallible sources: patient interviews; urine toxicology testing, and medical record review. Regression analyses based on a rule for classifying patients from this information can result in biased estimation of associations and variances due to the misclassification of some subjects and to the assumption of certainty. We describe a likelihood-based method that directly incorporates multiple sources of information regarding an outcome variable into a regression analysis and takes into account the uncertainty in the classification. The method can be applied when some sources of information are missing for some subjects. We show how the availability of multiple sources can be exploited to generate estimates of the quality (for example, sensitivity and specificity) of each source and to model the degree to which missing data are informative. A fitting algorithm and issues of identifiability are discussed. We illustrate the method using data from our study.

Stroke location is not associated with return to work after first ischemic stroke

BACKGROUND AND PURPOSE

In prior studies, age, race, job category, disability, and cortical functions such as praxis, language, and memory have been associated with vocational outcome, but the influence of stroke location on return to work has never been critically examined.

METHODS

We examined the influence of stroke location on vocational outcome in patients with clinically confirmed acute ischemic stroke from the National Institute of Neurological Disorders and Stroke Stroke Data Bank.

RESULTS

Of 143 patients working full time at the time of first ischemic stroke, 23 patients were dead and 120 were alive at 1 year. Employment status was known in 109 (mean age, 55 years; 51 [47%] were white, and 82 [75%] were male). Fifty-eight (53%) had returned to work; most (85%) worked full time. Younger age was positively associated with return to work (P<0.05). In an age-adjusted analysis, stroke severity as measured by the Barthel Index 7 to 10 days after stroke was negatively associated with return to work (P<0.001). Higher household income and absence of cortical neurological dysfunction 7 to 10 days after stroke were positively but less strongly associated with return to work (P<0.08). Stroke location, sex, and depression at time of stroke were not associated with vocational outcome.

CONCLUSIONS

Our data suggest that stroke location may be less important than other more easily measured factors in predicting vocational outcome.

Racial differences in prevalence of cobalamin and folate deficiencies in disabled elderly women

BACKGROUND

Many previous investigations of cobalamin and folate status were performed in white populations.

OBJECTIVE

Our objective was to determine whether there are racial differences in the prevalence of cobalamin and folate deficiency.

DESIGN

The study was a cross-sectional comparison of baseline serum cobalamin, folate, methylmalonic acid (MMA), total homocysteine (tHcy), and creatinine concentrations, complete blood count, and vitamin supplementation in 550 white and 212 African American subjects from a cohort of physically disabled older women.

RESULTS

The mean (+/-SD) serum MMA concentration was significantly higher in whites than in African Americans: 284 +/- 229 compared with 218 +/- 158 nmol/L (P = 0.0001). tHcy concentration was higher in African Americans than in whites: 12.4 +/- 7.0 compared with 10.9 +/- 4.6 micromol/L (P = 0.001). Serum cobalamin was lower in whites (P = 0.0002). Cobalamin deficiency (serum cobalamin <258 pmol/L and MMA >271 nmol/L) was more frequent in the white women (19% compared with 8%; P < 0.0003). Folate deficiency (serum folate <11.4 nmol/L, tHcy >13.9 micromol/L, and MMA <271 nmol/L) was more prevalent in African Americans than in whites (5% compared with 2%; P = 0.01). Multivitamin use was associated with lower tHcy but not with MMA concentrations. Regression models showed that age >85 y, African American race, serum creatinine >90 micromol/L, and high MMA concentration were all significantly correlated with higher tHcy. Creatinine > 90 micromol/L, white race, and folate concentration were positively associated with MMA concentration.

CONCLUSIONS

Cobalamin deficiency with elevated serum MMA concentration is more prevalent in elderly white than in African American women and elevated serum tHcy and folate deficiency are more prevalent in elderly African American than in white women.

Homocyst(e)ine and risk of cerebral infarction in a biracial population : the stroke prevention in young women study

BACKGROUND AND PURPOSE

Genetic enzyme variation and vitamin intake are important determinants of blood homocyst(e)ine levels. The prevalence of common genetic polymorphisms influencing homocyst(e)ine levels varies by race, and vitamin intake varies by socioeconomic status. Therefore, we examined the effect of vitamin intake, race, and socioeconomic status on the association of homocyst(e)ine with stroke risk.

METHODS

All 59 hospitals in the greater Baltimore-Washington area participated in a population-based case-control study of stroke in young women. One hundred sixty-seven cases of first ischemic stroke among women aged 15 to 44 years were compared with 328 controls identified by random-digit dialing from the same region. Risk factor data were collected by standardized interview and nonfasting phlebotomy. Plasma homocyst(e)ine was measured by high-performance liquid chromatography and electrochemical detection.

RESULTS

Blacks and whites did not differ in median homocyst(e)ine levels, nor did race modify the association between homocyst(e)ine and stroke. After adjustment for cigarettes per day, poverty status, and regular vitamin use, a plasma homocyst(e)ine level of >/=7.3 micromol/L was associated with an odds ratio for stroke of 1.6 (95% CI, 1.1 to 2.5).

CONCLUSIONS

The association between elevated homocyst(e)ine and stroke was independent not only of traditional vascular risk factors but also of vitamin use and poverty status. The degree of homocyst(e)ine elevation associated with an increased stroke risk in young women is lower than that previously reported for middle-aged men and the elderly and was highly prevalent, being present in one third of the control group.

Distribution and correlates of elevated total homocyst(e)ine: the Stroke Prevention in Young Women Study

PURPOSE

To determine the distribution and correlates of elevated total homocyst(e)ine (tHcy) concentration in a population of premenopausal black and white women.

METHODS

Data from the Stroke Prevention in Young Women Study (N = 304), a population-based study of risk factors for stroke in women aged 15-44 years of age, were used to determine the distribution and correlates of elevated tHcy in black (N = 103) and white women (N = 201).

RESULTS

The mean tHcy level for the population was 6.58 micromol/L (range 2.89-26.5 micromol/L). Mean tHcy levels increased with age, cholesterol level, alcohol intake, and number of cigarettes smoked (all: p < 0.05). There were no race differences (mean tHcy 6.72 micromol/L among blacks and 6.51 micromol/L among whites; p = 0.4346). Regular use of multivitamins and increasing education was associated with significant reductions in tHcy concentration. Approximately 13% of the sample had elevated tHcy levels, defined as a tHcy concentration > or = 10.0 micromol/L. Multivariate-adjusted correlates of elevated tHcy included education > 12 vs. < or = 12 (odds ratio [OR] = 0.4, 95% confidence interval [CI] = 0.2-0.8); smoking > or = 20 cigarettes/day vs. nonsmokers (OR = 2.8, 95% CI = 1.1-7.3); and the regular use of multivitamins (OR = 0.4, 95% CI = 0.2-0.9).

CONCLUSIONS

These results suggest that a substantial proportion of healthy young premenopausal women have tHcy levels that increase their risk for vascular disease. A number of potentially modifiable behavioral and environmental factors appear to be significantly related to elevated tHcy levels in young women.

Effects of menopause on seizures in women with epilepsy

PURPOSE

Although important associations between epilepsy and women's hormonal phases are described, the relation of menopause to epilepsy has received little attention.

METHODS

By using a structured interview, we studied menopausal women with epilepsy seen at the University of Maryland Epilepsy Center over a 1-year period from 1994 to 1995. We analyzed the characteristics and temporal relation of the seizures to menopause and compared the frequency and severity of the seizures with those in a similar group of premenopausal women.

RESULTS

We identified 61 menopausal women (46 who were postmenopausal and 15 perimenopausal) and compared them with 46 premenopausal women. No statistically significant differences were noted in either the frequency or the severity of seizures comparing all menopausal or only postmenopausal with premenopausal women. However, 12 (20%) of the 61 menopausal women noted that their seizures first began during or after menopause, with eight having no proven cause for their seizures. Many individual women described changes in their seizures with menopause. Among the 61 menopausal women, 49 had established epilepsy before the onset of menopause, and 20 (41%) reported worsening of their seizures with menopause, 13 (27%) noted improvement, and 16 (33%) described no changes. These observations were similar for peri- and postmenopausal women. Of the 15 menopausal women taking hormone replacement therapy, the six taking progestin were significantly less likely to report worsening of their seizures.

CONCLUSIONS

These findings support the view that hormonal influences are important in women with seizures. Although, in aggregate, menopausal (combined perimenopausal and postmenopausal) and postmenopausal women's seizures were similar in frequency and severity to those of other women, menopause was associated with changes in seizures for some women. Moreover, menopause may be a previously unrecognized factor for some new-onset seizures. The relations between menopause and epilepsy deserve to be more fully investigated.

Oral anticoagulation in patients with atrial fibrillation: adherence with guidelines in an elderly cohort

PURPOSE

To determine adherence with practice guidelines in a population-based cohort of elderly persons aged 70 years or older with atrial fibrillation.

SUBJECTS AND METHODS

This was a cross-sectional analysis of a subgroup of participants in the Cardiovascular Health Study, a prospective observational study involving four communities in the United States. Subjects were participants with atrial fibrillation on electrocardiogram at one or more yearly examinations from 1993 to 1995. The outcome measure was self-reported use of warfarin in 1995.

RESULTS

In 1995, 172 (4.1%) participants had atrial fibrillation together with information regarding warfarin use and no preexisting indication for its use. Warfarin was used by 63 (37%) of these participants. Of the 109 participants not reporting warfarin use, 92 (84%) had at least one of the clinical risk factors (aside from age) associated with stroke in patients with atrial fibrillation. Among participants not taking warfarin, 47% were taking aspirin. Several characteristics were independently associated with warfarin use, including age [odds ratio (OR) = 0.6 per 5-year increment, 95% CI 0.5-0.9], a modified mini-mental examination score <85 points [OR = 0.3, 95% confidence interval (CI) 0.1-0.9], and among patients without prior stroke, female sex (OR = 0.5, 95% CI 0.2-1.0).

CONCLUSIONS

Despite widely publicized practice guidelines to treat patients who have atrial fibrillation with warfarin, most participants who had atrial fibrillation were at high risk for stroke but were not treated with warfarin. More studies are needed to determine why elderly patients with atrial fibrillation are not being treated with warfarin.

Elevated tissue plasminogen activator antigen and stroke risk: The Stroke Prevention In Young Women Study

BACKGROUND AND PURPOSE

Abnormalities in endogenous fibrinolysis are associated with an increased risk for stroke in men and older adults. We tested the hypothesis that elevated plasma tissue plasminogen activator (tPA) antigen, a marker for impaired endogenous fibrinolysis, is an independent risk factor for stroke in young women.

METHODS

Subjects were 59 nondiabetic females ages 15 to 44 years with cerebral infarction from the Baltimore-Washington area and 97 control subjects frequency-matched for age who were recruited by random-digit dialing from the same geographic area. A history of cerebrovascular disease risk factors was obtained by face-to-face interview. Plasma tPA antigen was measured by enzyme-linked immunosorbent assay.

RESULTS

Mean plasma tPA antigen levels were significantly higher in stroke patients than control subjects (4. 80+/-4.18 versus 3.23+/-3.67 ng/mL; P=0.015). After adjustment for age, hypertension, cigarette smoking, body mass index, and ischemic heart disease, there was a dose-response association between tPA antigen and stroke with a 3.9-fold odds ratio of stroke (95% CI, 1.2 to 12.4; P=0.03) for the upper quartile (>4.9 ng/mL) of tPA antigen compared with the lowest quartile. The dose-response relationship between tPA antigen and stroke was equally present in white and nonwhite women, and further adjustment for total and HDL cholesterol levels only modestly attenuated this association.

CONCLUSIONS

This population-based case-control study shows that elevated plasma tPA antigen level is independently associated with an increased risk for ischemic stroke in nondiabetic females 15 to 44 years of age. These findings support the hypothesis that impaired endogenous fibrinolysis is an important risk factor for stroke in young women.

Total homocyst(e)ine concentration and the likelihood of nonfatal stroke: results from the Third National Health and Nutrition Examination Survey, 1988-1994

BACKGROUND AND PURPOSE

Elevated serum total homocyst(e)ine [H(e)] is an independent risk factor for stroke. Few studies, however, have examined this association in blacks.

METHODS

Data from the Third National Health and Nutrition Examination Survey (n=4534), a nationally representative sample of US adults, were used to examine the relationship between H(e) and a physician diagnosis of stroke (n=185) in both black and white adults. Multivariate-adjusted logistic regression analyses were used to examine this relationship.

RESULTS

Serum vitamin B12 and folate concentrations were significantly lower among participants in the highest H(e) quartile (>/=12.1 micromol/L) than among participants in the lowest quartile (</=7.4 micromol/L). Those in the highest quartile were older, had higher mean cholesterol and blood pressure levels, and were more likely to smoke and to have completed <12 years of education. After adjustment for age, the odds ratio (OR) for stroke was 2.9 (95% confidence interval [CI], 1.4 to 5.7; highest versus lowest quartile). Adjustment for gender, race/ethnicity, education, systolic blood pressure, cholesterol, diabetes mellitus, and smoking reduced the magnitude of the association (OR, 2.3; 95% CI, 1.2 to 4. 6). The association between H(e) and stroke did not differ by race [P=0.265 for race-H(e) interaction term]. The multivariate adjusted OR for the highest quartile versus the lowest was 2.5 (1.1 to 5.5) among whites and 1.4 (0.4 to 4.7) among blacks.

CONCLUSIONS

In this nationally representative sample of US adults, H(e) concentration was independently associated with an increased likelihood of nonfatal stroke. This association was present in both black and white adults.

Serum folate and risk for coronary heart disease: results from a cohort of US adults

PURPOSE

To assess the role of serum folate in the risk for coronary heart disease in a national cohort of US adults.

METHODS

Data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study (N = 1921) were used to determine whether a low serum folate concentration was associated with an increased risk for incident coronary heart disease (N = 284). The Cox proportional hazards model adjusted for age, sex, race, education, serum cholesterol, systolic blood pressure, body mass index, cigarette smoking, and alcohol consumption.

RESULTS

The association between folate and risk for coronary heart disease differed by age group (p = 0.03). Among persons aged 35-55 years, the relative risk for heart disease was 2.4 (95% confidence interval (CI), 1.1-5.2) for persons in the lowest quartile (< or = 9.9 nmol/L) when compared with those in the highest quartile (> or = 21.8 nmol/L). However, among persons > or = 55 years the relative risk was 0.5 (95% CI, 0.3-0.8) for comparisons of the lowest versus highest quartiles.

CONCLUSIONS

If the age differences in the risk for heart disease are confirmed, randomized clinical trials assessing the role of folic acid for the prevention of heart disease may need to include young adults in order to demonstrate benefits related to folate supplementation.

Thermolabile methylenetetrahydrofolate reductase polymorphism (C677T) and total homocysteine concentration among African-American and white women

A polymorphism associated with a thermolabile variant (C677T) of the enzyme methylenetetrahydrofolate reductase has been associated with both elevated total homocysteine (tHcy) levels and risk for cardiovascular disease. Data from the Stroke Prevention in Young Women Study were used to determine the prevalence of the C677T genotype and to assess whether environmental factors modified the association between genotype and tHcy concentration. The C677T genotype prevalence was 80% -/-, 20% +/-, and 0% +/+ among 46 African-American women; and 39% -/-, 53% +/-, and 8% +/+ among 77 white women (P < 0.01). There was a trend toward higher tHcy levels in African-American women with the +/- genotype when compared with the -/- genotype (6.9 mumol/L vs 5.3 mumol/L respectively, p = 0.10); no association was found among the white women (6.0 mumol/L, -/-; 4.5 mumol/L, +/-; and 6.2 mumol/L, +/+; p = 0.67). Among African American women, those who smoked and were +/- genotype had the highest tHcy levels (8.0 mumol/L); while among white women, those who smoked and were -/- had the highest tHcy levels (8.1 mumol/L). Despite being hampered by a limited sample size, the thermolabile allele is significantly less common among African-American than white women. The association between genotype and tHcy concentration is influenced by smoking and multivitamin use.

Stroke in children and sickle-cell disease: Baltimore-Washington Cooperative Young Stroke Study

BACKGROUND/PURPOSE

The Baltimore-Washington Cooperative Young Stroke Study is the largest biracial urban-suburban population-based study to examine the etiology of strokes in children.

METHODS

We identified all children aged 1 to 14 years discharged from all 46 hospitals in central Maryland and Washington, DC with a diagnosis of ischemic stroke and intracerebral hemorrhage in the years 1988 and 1991. Each medical record was reviewed by two neurologists for appropriateness of the diagnosis of stroke and for information on the patient's history, clinical presentation, pertinent investigations, hospital stay, and outcome at time of discharge.

RESULTS

Eighteen children with ischemic infarction and 17 with intracerebral hemorrhage were identified. The most common cause of ischemic stroke was sickle-cell disease (39%), followed by vasculopathic (33%) and indeterminate (28%) causes. Causes of intracerebral hemorrhages were arteriovenous malformation (29%), hematologic (23%), vasculopathy (18%), surgical complication (12%), coagulopathy (6%), and indeterminate (12%). The overall incidence for childhood stroke was 1.29 per 100,000 per year, with ischemic stroke occurring at a rate of 0.58 per 100,000 and intracerebral hemorrhage occurring at a rate of 0.71 per 100,000. The incidence of stroke among children with sickle-cell disease was estimated to be 0.28% or 285 per 100,000 per year.

CONCLUSION

Sickle-cell disease plays a disproportionately high role in childhood stroke when a biracial population is surveyed.

Illicit drug-associated ischemic stroke in the Baltimore-Washington Young Stroke Study

BACKGROUND

Limited information exists on the frequency, trends in occurrence, risk factors, mechanisms, and outcome of ischemic stroke associated with illicit drug use among young adults in a geographically defined population.

METHODS

We reviewed ischemic stroke in young adults (aged 15 to 44 years) in 46 regional hospitals for 1988 and 1991. We examined stroke mechanisms and outcome in patients with recent drug use.

RESULTS

Recent illicit drug use was noted in 51/422 (12.1%) stroke patients. Patients with drug use were more likely than other stroke patients to be black (p=0.01), aged 25 to 39 years (p=0.004), and smokers (p=0.006), and were less likely to have hypertension (p=0.004) or diabetes mellitus (p=0.004). Drug use was the probable cause of stroke in 20 (4.7%) patients. Among 31 (7.3%) patients with drug use as a possible stroke mechanism, more likely diagnoses included cardioembolic stroke in 18, hematologic/collagen vascular in 6, nonatherosclerotic vasculopathy in 5, and atherosclerosis in 3. There was no difference in outcome between drug-associated and non-drug associated stroke.

CONCLUSIONS

Recent illicit drug use occurs in 12.1% of young adult stroke patients. Drug-associated young adult stroke seems to relate to vascular mechanisms other than those related to hypertension or diabetes. Case-control studies are needed.

Cerebral infarction in young adults: the Baltimore-Washington Cooperative Young Stroke Study

BACKGROUND

Few reports on stroke in young adults have included cases from all community and referral hospitals in a defined geographic region.

METHODS

At 46 hospitals in Baltimore City, 5 central Maryland counties, and Washington, DC, the chart of every patient 15 to 44 years of age with a primary or secondary diagnosis of possible cerebral arterial infarction during 1988 and 1991 was abstracted. Probable and possible etiologies were assigned following written guidelines.

RESULTS

Of 428 first strokes, 212 (49.5%) were assigned at least one probable cause, 80 (18.7%) had no probable cause but at least one possible cause, and 136 (31.8%) had no identified probable or possible cause. Of the 212 with at least one probable cause, the distribution of etiologies was cardiac embolism (31.1%), hematologic and other (19.8%), small vessel (lacunar) disease (19.8%), nonatherosclerotic vasculopathy (11.3%), illicit drug use (9.4%), oral contraceptive use (5.2%), large artery atherosclerotic disease (3.8%), and migraine (1.4%). There were an additional 69 recurrent stroke patients.

CONCLUSIONS

In this hospital-based registry within a region characterized by racial/ethnic diversity, cardiac embolism, hematologic and other causes, and lacunar stroke were the most common etiologies of cerebral infarction in young adults. Nearly a third of both first and recurrent strokes had no identified cause.

Platelet glycoprotein receptor IIIa polymorphism P1A2 and ischemic stroke risk: the Stroke Prevention in Young Women Study

BACKGROUND AND PURPOSE

Platelet glycoprotein IIb/IIa (GpIIb-IIIa), a membrane receptor for fibrinogen and von Willebrand factor, has been implicated in the pathogenesis of acute coronary syndromes but has not been previously investigated in relation to stroke in young adults.

METHODS

We used a population-based case-control design to examine the association of the GpIIIa polymorphism P1A2 with stroke in young women. Subjects were 65 cerebral infarction cases (18 patients with and 47 without an identified probable etiology) 15 to 44 years of age from the Baltimore-Washington region and 122 controls frequency matched by age from the same geographic area. A face-to-face interview for vascular disease risk factors and a blood sample for the P1A2 allele and serum cholesterol were obtained from each participant. Logistic regression was used to estimate the odds ratio for one or more P1A2 alleles after adjustment for other risk factors.

RESULTS

Among cases and controls, the prevalence rates of one or more P1A2 alleles were 21% and 22% among blacks and 36% and 28% among whites, respectively. This genotype was significantly associated with hypertension only in black control subjects but otherwise not with any of the established vascular risk factors. The adjusted odds ratio for cerebral infarction of one or more P1A2 alleles was 1.1 (confidence interval [CI], 0.6 to 2.3) overall, 0.5 (CI, 0.1 to 7.1) among blacks, and 1.4 (CI, 0.5 to 3.7) among whites. For the cases with an identified probable etiology, the corresponding odds ratios were 3.0 (CI, 0.9 to 10.4) overall, 0.7 (CI, 0.1 to 7.1) among blacks, and 12.8 (CI, 1.2 to 135.0) among whites.

CONCLUSIONS

No association was found between the P1A2 polymorphism of GpIIIa and young women with stroke. However, subgroup analyses showed that the P1A2 polymorphism of GpIIIa appeared to be associated with stroke risk among white women, particularly those with a clinically identified probable etiology for their stroke. Further work with an emphasis on stroke subtypes and with multiracial populations is warranted.

Silent brain infarction on magnetic resonance imaging and neurological abnormalities in community-dwelling older adults. The Cardiovascular Health Study. CHS Collaborative Research Group

BACKGROUND AND PURPOSE

Infarctlike lesions are frequently detected in symptomatic and asymptomatic older persons undergoing cerebral MRI, but their significance in older adults has not been examined. We determined the prevalence of MRI infarcts in a population-based sample of men and women aged > or = 65 years and related these findings to demographic, cognitive, and neurological status.

METHODS

MRI scanning was performed in 3660 Cardiovascular Health Study (CHS) participants after brief neurological examinations and tests of cognitive function. MRIs were read centrally for the presence of an infarct > or = 3 mm in diameter or smaller infarctlike lesions.

RESULTS

MRI infarcts were detected in 1131 of 3647 participants with readable infarct information (31%) and in 961 of the subgroup of 3397 participants (28%) without known prior stroke ("silent" MRI infarcts). Smaller infarctlike lesions were found in 196 of 2516 participants who had no MRI infarcts > or = 3 mm. MRI infarcts were more common in participants who were older, had prior stroke, impaired cognition, visual field deficits, slowed repetitive finger tapping (all P < .0001), weakness on toe and heel walking, and history of memory loss, coma, or migraine headaches. Multivariate analysis in those without prior stroke showed strong associations of silent MRI infarcts with older age, history of migraines, lower digit symbol scores, and more abnormalities on neurological examination.

CONCLUSIONS

MRI evidence of brain infarction is common in older men and women without a clinical history of stroke. Their strong associations with impaired cognition and neurological deficits suggest that they are neither silent nor innocuous.

Pregnancy and the risk of stroke

BACKGROUND

It is widely believed that pregnancy increases the risk of stroke, but there are few data available to quantify that risk.

METHODS

We identified all female patients 15 through 44 years of age in central Maryland and Washington, D.C., who were discharged from any of 46 hospitals in the study area in 1988 or 1991. Two neurologists reviewed each case, using data from the women's medical records. We determined whether the women had been pregnant at the time of the stroke or up to six weeks before it occurred. For purposes of this analysis, the six-week period after pregnancy could begin with an induced or spontaneous abortion or with the delivery of a live or stillborn child.

RESULTS

Seventeen cerebral infarctions and 14 intracerebral hemorrhages occurred in women who were or had recently been pregnant (pregnancy-related strokes), and there were 175 cerebral infarctions and 48 intracerebral hemorrhages that were not related to pregnancy. For cerebral infarction, the relative risk during pregnancy, adjusted age and race, was 0.7 (95 percent confidence interval, 0.3 to 1.6), but it increased to 8.7 for the postpartum period (after a live birth or stillbirth) (95 percent confidence interval, 4.6 to 16.7). For intracerebral hemorrhage, the adjusted relative risk was 2.5 during pregnancy (95 percent confidence interval, 1.0 to 6.4) but 28.3 for the postpartum period (95 percent confidence interval, 13.0 to 61.4). Overall, for either type of stroke during or within six weeks after pregnancy, the adjusted relative risk was 2.4 (95 percent confidence interval, 1.6 to 3.6), and the attributable, or excess, risk was 8.1 strokes per 100,000 pregnancies (95 percent confidence interval, 6.4 to 9.7).

CONCLUSIONS

The risks of both cerebral infarction and intracerebral hemorrhage are increased in the six weeks after delivery but not during pregnancy itself.

Thickening of the carotid wall. A marker for atherosclerosis in the elderly? Cardiovascular Health Study Collaborative Research Group

BACKGROUND AND PURPOSE

We investigated the relationships between prevalent coronary heart disease (CHD), clinically manifest atherosclerotic disease (ASD), and major established risk factors for atherosclerosis and intima-media thickness (IMT) in the common carotid arteries (CCA) and internal carotid arteries (ICA) separately and in combination in older adults. We wished to determine whether a noninvasive measurement can serve as an indicator of clinically manifest atherosclerotic disease and to determine which of the two variables, CCA IMT or ICA IMT, is a better correlate.

METHODS

IMT of the CCA and ICA was measured with duplex ultrasound in 5117 of 5201 individuals enrolled in the Cardiovascular Health Study, a study of the risk factors and the natural history of cardiovascular disease in adults aged 65 years or more. Histories of CHD, peripheral arterial disease, and cerebrovascular disease were obtained during baseline examination. Risk factors included cholesterol levels, cigarette smoking, elevated blood pressure, diabetes, age, and sex. Relationships between risk factors and IMT were studied by multiple regression analysis and canonical variate analysis. Prediction of prevalent CHD and ASD by IMT measurements in CCAs and ICAs were made by logistic regression, adjusting for age and sex.

RESULTS

IMT measurements of the CCAs and ICAs were greater in persons with CHD and ASD than those without, even after controlling for sex (P < .001). IMT measurements in the ICA were greater than those in the CCA. Risk factors for ASD accounted for 17% and 18% of the variability in IMT in the CCA and ICA, respectively. These same risk factors accounted for 25% of the variability of a composite measurement consisting of the sum of the ICA IMT and CCA IMT. The ability to predict CHD and ASD was greater for ICA IMT (odds ratio [confidence interval]: 1.36 [1.31 to 1.41] and 1.35 [1.25 to 1.44], respectively) than for CCA IMT (1.09 [1.05 to 1.13] and 1.17 [1.09 to 1.25]).

CONCLUSIONS

Whereas CCA IMT is associated with major risk factors for atherosclerosis and existing CHD and ASD in older adults, this association is not as strong as that for ICA IMT. The combination of these measures relates more strongly to existing CHD and ASD and cerebrovascular disease risk factors than either taken alone.

Stroke in children and young adults

This selective review of stroke in children and young adults addresses: (1) stroke in sickle cell disease, particularly the prognostic use of transcranial Doppler, (2) oral contraceptives as a stroke risk factor, (3) stroke in pregnancy, and (4) the prognosis of ischemic stroke in young adults. Factors relevant to the primary prevention and outcome of stroke are emphasized.

Patent foramen ovale: association between the degree of shunt by contrast transesophageal echocardiography and the risk of future ischemic neurologic events

This study investigated whether there is an association between the degree of interatrial shunting across a patent foramen ovale, as determined by saline contrast transesophageal echocardiography, and the risk of subsequent systemic embolic events, including stroke. Thirty-four patients found to have foramen ovale during transesophageal echocardiography were divided into two groups on the basis of the maximum number of microbubbles in the left heart in any single frame after intravenous saline contrast injection: group 1 (n = 16) with a "large" degree of shunt ( > or = 20 microbubbles) and group 2 (n = 18) with a "small" degree of shunt ( > or = 3 microbubbles). Patients were followed up over a mean period of 21 months for subsequent systemic embolic events, including transient ischemic attack and stroke. Five (31%) of the patients with large shunts had subsequent ischemic neurologic events, whereas none of the patients with small shunts had embolic events (p = 0.03). These events occurred in spite of antiplatelet or anticoagulant therapy. We conclude that patients with a large degree of shunt across a patient foramen ovale, as determined by contrast transesophageal echocardiography, are at a significantly higher risk of subsequent adverse neurologic events compared with patients with a small degree of shunt.

Methods of assessing prevalent cardiovascular disease in the Cardiovascular Health Study

The objective of this article is to describe the methods of assessing cardiovascular conditions among older adults recruited to the Cardiovascular Health Study (CHS), a cohort study of risk factors for coronary disease and stroke. Medicare eligibility lists from four US communities were used to obtain a representative sample of 5201 community-dwelling elderly, who answered standardized questionnaires and underwent an extensive clinic examination at baseline. For each cardiovascular condition, self-reports were confirmed by components of the baseline examination or, if necessary, by a validation protocol that included either the review of medical records or surveys of treating physicians. Potential underreporting of a condition was detected either by the review of medical records at baseline for other self-reported conditions or, during prospective follow-up, by the investigation of potential incident events. For myocardial infarction, 75.5% of the self-reports in men and 60.6% in women were confirmed. Self-reported congestive heart failure was confirmed in 73.3% of men and 76.6% of women; stroke, in 59.6% of men and 53.8% of women; and transient ischemic attack, in 41.5% of men and 37.0% of women. Underreporting was also common. During prospective follow-up of an average of about 3 years per person, approximately 50% of men and 38% of women were hospitalized or investigated for at least one potential incident event; for each cardiovascular condition, about 1 to 4% of those investigated during prospective follow-up were found to have had the cardiovascular condition prior to entry into the cohort.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum folate and risk for ischemic stroke. First National Health and Nutrition Examination Survey epidemiologic follow-up study

BACKGROUND AND PURPOSE

A serum folate concentration < or = 9.2 nmol/L has been associated with elevated levels of plasma homocyst(e)ine. Elevated homocyst(e)ine levels have been associated with ischemic stroke in case-control studies; however, the results from prospective studies have been equivocal. We investigated whether a folate concentration < or = 9.2 nmol/L was associated with ischemic stroke in a national cohort.

METHODS

We used data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study (n = 2006). Cox proportional hazards analyses were used to adjust for differences in follow-up time and covariates. During the 13-year follow-up, 98 ischemic strokes occurred.

RESULTS

After adjusting for age, race, sex, education, diabetes, history of heart disease, systolic blood pressure, body mass index, hemoglobin level, cigarette smoking, and alcohol intake, participants with a folate concentration < or = 9.2 nmol/L were at slightly increased risk for ischemic stroke (relative risk [RR], 1.37; 95% confidence interval [CI], 0.82 to 2.29). There was a folate-race interaction (P = .11 for interaction term). Whites with a folate concentration < or = 9.2 nmol/L had a relative risk of 1.18 (95% CI, 0.67 to 2.08), whereas blacks had a relative risk of 3.60 (95% CI, 1.02 to 12.71).

CONCLUSIONS

These findings suggest that a folate concentration < or = 9.2 nmol/L may be a risk factor for ischemic stroke, especially in blacks. However, given the small number of stroke events, additional studies are needed to assess the role of folate in the epidemiology of ischemic stroke.

Ulcerated atherosclerotic plaques in the thoracic aorta are associated with cryptogenic stroke: a multiplane transesophageal echocardiographic study

Atherosclerotic plaque ulcers > or = 2 mm in depth and width in the thoracic aorta have been implicated by autopsy study as a cause of unexplained or cryptogenic ischemic strokes. Transesophageal echocardiography (TEE) allows visualization of complex atherosclerotic lesions of the thoracic aorta. We compared the prevalence of thoracic aorta ulcerated plaques (ulcers > or = 2 mm in both depth and width) in three age-matched groups undergoing multiplane TEE: group 1, 23 patients with cryptogenic ischemic stroke; group 2, 26 patients with known-cause strokes; and group 3, 57 control patients without strokes. TEEs were interpreted in a blinded fashion. Ulcerated plaques were found in 9 (39%) group 1 patients but in only 2 (8%) group 2 patients and in only 4 (7%) group 3 patients (p < 0.001). There was an association between advancing age and the presence of ulcerated plaques (p < 0.02). We conclude that ulcerated atherosclerotic plaques in the thoracic aorta are associated with cryptogenic ischemic stroke and should be considered a potential source of cerebral emboli.

Determinants of black-white differences in the risk of cerebral infarction. The National Health and Nutrition Examination Survey Epidemiologic Follow-up Study

OBJECTIVE

To determine whether blacks in the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study remained at increased risk for cerebral infarction after adjusting for stroke risk factors and sociodemographic factors.

METHODS

A cohort study involving 8203 whites and 1362 blacks who participated in the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. During the 13-year follow-up, 538 and 122 cerebral infarctions occurred in whites and blacks, respectively.

RESULTS

The black-white risk for cerebral infarction varied by age (P = .007 for race-age interaction). Compared with whites of the same age, blacks aged 35 to 44 years were at significantly increased risk for cerebral infarction (relative risk, 2.62; 95% confidence interval, 1.23 to 5.57), while older blacks, those older than 64 years, were not at increased risk (relative risk, 1.14; 95% confidence interval, 0.90 to 1.46). The relative risk for cerebral infarction decreased to 2.07 (95% confidence interval, 0.97 to 4.42) in younger blacks and 0.82 (95% confidence interval, 0.29 to 2.33) in older blacks after adjustment for age, sex, education, history of heart disease, diabetes, systolic blood pressure, treatment for hypertension, Quetelet index, and serum hemoglobin and magnesium levels.

CONCLUSIONS

These results indicate that much of the increased risk for cerebral infarction experienced by blacks can be explained by their higher prevalence of stroke risk factors, especially diabetes, hypertension, and lower educational attainment. Younger blacks, however, may still be at increased risk after adjusting for stroke risk factors.

Education and change in cognitive function. The Epidemiologic Catchment Area Study

The association between educational attainment and decline in cognitive function over an interval of 1 year was examined for 14,883 subjects 18 years and older in the National Institute of Mental Health Epidemiologic Catchment Area Study. Cognitive function was assessed at both time points by the Mini-Mental State Examination (MMSE); cognitive decline was coded as a dichotomous variable and was defined as 1 if the subject's score had declined 3 or more points from the baseline MMSE score at the 1-year follow-up interview and as 0 otherwise. The association between educational attainment and decline in cognitive function over 1 year was examined in logistic regression models that were stratified by age group (< 65 years, > or = 65 years) and by baseline MMSE level (MMSE > 23, MMSE < or = 23). Covariates included age, baseline MMSE score, ethnicity, residence, lifetime diagnosis of abuse of alcohol or other drugs, and gender. In those with baseline MMSE > 23, education was a significant predictor of cognitive decline, not only in the elderly but also in younger subjects. Among those with baseline MMSE < or = 23, education was not a significant predictor of cognitive decline. The fact that education provides protection against cognitive decline even in those younger than 65 years, in whom the prevalence and incidence of dementia are very low, would seem to indicate that education or its correlates provides protection against processes other than dementia that might produce a decline in test performance in young persons.

Interrater reliability of an etiologic classification of ischemic stroke

BACKGROUND AND PURPOSE

Precise identification of the cause of stroke is critical to research and clinical practice. Published series of ischemic stroke show considerable variation in the proportion of cases classified as atherosclerotic large-vessel disease, lacunar infarct, cardioembolic stroke, stroke of other known cause, and stroke of undetermined etiology. We describe the development and use of an etiology-specific classification of ischemic stroke. The interrater reliability of the classification is then evaluated.

METHODS

A total of 160 cases of ischemic strokes in young adults were reviewed by paired neurologists who assigned cases to prioritized categories. The results of paired ratings were evaluated for each of the potential causes. Interrater agreement was assessed by means of kappa, which is the chance-adjusted percent agreement.

RESULTS

For standard pairs, kappa was fair to good for all causes except lacunar stroke (kappa = 0.31); however, pair-to-pair variation was greatest for lacunar strokes. Strokes of undetermined cause and hematologic/other cause were of borderline fair reliability.

CONCLUSIONS

The utility of a stroke classification system is dependent on its intended use. An etiologic classification is useful in studies of the epidemiology and pathophysiological basis of stroke. Fair to good reliability for an etiologic classification of stroke can be obtained when criteria are explicit.

Relation of smoking with carotid artery wall thickness and stenosis in older adults. The Cardiovascular Health Study. The Cardiovascular Health Study (CHS) Collaborative Research Group

BACKGROUND

Cigarette smoking has been associated with increased risk of atherosclerotic diseases in hospital-based studies and in studies of middle-aged populations but not in population-based studies of older adults with and without clinical cardiovascular disease.

METHODS AND RESULTS

We investigated the relation of smoking to carotid artery atherosclerotic disease, expressed as intimal-medial wall thickness and arterial lumen narrowing (stenosis) measured by ultrasound. Subjects were 5116 older adults participating in the baseline examination of the Cardiovascular Health Study, a community-based study of cardiovascular diseases in older age. With increased smoking there was significantly greater internal and common carotid wall thickening and internal carotid stenosis: current smokers > former smokers > never-smokers; for instance, the unadjusted percent stenosis was 24%, 20%, and 16%, respectively (P < .0001). A significant dose-response relation was seen with pack-years of smoking. These findings persisted after adjusting for other cardiovascular risk factors and were also confirmed when analyses were restricted to those without prevalent cardiovascular disease. The difference in internal carotid wall thickness between current smokers and nonsmokers was greater than the difference associated with 10 years of age among never-smoking participants (0.39 mm versus 0.31 mm). Among all participants, the prevalence of clinically significant (> or = 50%) internal carotid stenosis increased from 4.4% in never-smokers to 7.3% in former smokers to 9.5% in current smokers (P < .0001).

CONCLUSIONS

These findings extend previous reports of a positive relation between smoking and carotid artery disease to a population-based sample of older adults using several different indicators of atherosclerotic disease.

Use of Medicare claims data to estimate national trends in stroke incidence, 1985-1991

BACKGROUND AND PURPOSE

Although stroke mortality has been declining in the United States for decades, recent trends in stroke incidence based on national data have not been described. We used Medicare hospitalization data to estimate national trends in the incidence of stroke among Americans aged 70 years or older, and we provide evidence of the validity of the estimate.

METHODS

We defined stroke as a principal diagnosis with International Classification of Diseases, 9th Revision, Clinical Modification codes 430 to 434 or 436 to 437. We excluded many recurrent cases from the analysis by eliminating persons hospitalized for stroke during the 5 years preceding the index stroke. We calculated annual adjusted incidence rates and examined trends graphically. We investigated the effect of different exclusion periods, trends in in-hospital mortality of stroke patients, and trends in out-of-hospital stroke mortality. We examined trends in relation to sex, race, and age.

RESULTS

The estimated age- and sex-adjusted stroke incidence declined 9.5% from 1985 to 1989, then increased 3.3% to 1991. The pattern did not vary with the length of the exclusion period or when all listed diagnosis rather than principal diagnoses were used to identify stroke cases. Incidence trends resembled the overall trend for both men and women, for 5-year age groups, and for whites; the trend did not change for blacks.

CONCLUSIONS

Stroke incidence declined steadily from 1985 to 1989 and then increased slightly to 1991. Several postulated potential sources of bias were investigated and found to be unlikely to account for the incidence decline, although some may have contributed to the subsequent incidence increase.

Black-white differences in stroke risk among young adults

BACKGROUND AND PURPOSE

Little information is available regarding black-white differences in stroke incidence in young adults.

METHODS

Cerebral infarction and intracerebral hemorrhage rates among adults 15 to 44 years of age were studied in Baltimore City and Baltimore County for 1988. Diagnoses were based on neurologist review of data obtained from medical records at 41 hospitals by neurological nurses.

RESULTS

The cerebral infarction rates per 100,000 were 22.8 for black males, 10.3 for white males, 20.7 for black females, and 10.8 for white females. The intracerebral hemorrhage rates per 100,000 were 14.2 for black males, 4.6 for white males, 4.8 for black females, and 1.5 for white females.

CONCLUSIONS

Blacks had significantly (P < .05) higher rates than whites for both cerebral infarction and intracerebral hemorrhage. Cerebral infarction rates are high in Baltimore compared with Florence, Italy, or Stockholm, Sweden.

Sonographic evaluation of carotid artery atherosclerosis in the elderly: relationship of disease severity to stroke and transient ischemic attack

Doppler and real-time ultrasound (US) were performed to evaluate the extent of atherosclerotic changes in the carotid artery and to assess their relationship to prevalent cerebrovascular disease. Real-time US scans and Doppler measurements of the carotid arteries were analyzed in 5,201 subjects aged 65 years or older. Severity of atherosclerotic lesions was associated with increased frequencies of hyperechoic, irregular, and heterogeneous textured lesions (P < .0001). The severity of internal carotid artery stenosis was associated with thickening of the intima-media layer of the common carotid artery wall (r = .37, P < .0001). A history of stroke and transient ischemic attack (TIA) was more likely when hyperechoic, heterogeneous, and irregular lesions were seen in the carotid artery. Internal carotid artery stenosis correlated better with prevalent stroke and TIA than did sonographic descriptions of plaque texture. However, the prevalence of hyperechoic, heterogeneous, and irregular lesions increased as the degree of internal carotid stenosis increased. On real-time images alone, the average of the internal carotid artery maximal wall thickness is the sonographic measure of atherosclerosis that enables the best prediction of prevalent stroke and TIA.

Distribution and correlates of sonographically detected carotid artery disease in the Cardiovascular Health Study. The CHS Collaborative Research Group

BACKGROUND AND PURPOSE

This article describes the prevalence of extracranial carotid atherosclerosis assessed by ultrasonography, its association with risk factors, and its relation to symptomatic coronary disease and stroke in men and women aged > or = 65 years.

METHODS

Maximum percent stenosis, maximum common carotid artery wall thickness, and maximum internal carotid artery wall thickness were assessed using duplex ultrasound in 5,201 men and women aged > or = 65 years in the Cardiovascular Health Study, a study of the risk factors and natural history of cardiovascular disease in the elderly. Existing coronary disease and stroke were assessed by physical examination and participant history.

RESULTS

Detectable carotid stenosis was present in 75% of men and 62% of women, although the prevalence of > or = 50% stenosis was low, 7% in men and 5% in women. Maximum stenosis and maximum wall thickness measurements increased with age and were uniformly greater at all ages in men than in women (p < 0.00001). Established risk factors for atherosclerosis (hypertension, smoking, diabetes) and indications of vascular disease (left ventricular hypertrophy, major electrocardiographic abnormality, bruits, and history of heart disease or stroke) related to all three carotid artery measures in the elderly. Of the three ultrasound measures, the best correlate for a history of coronary disease was maximum internal carotid artery wall thickness. For stroke the best correlate was common carotid artery wall thickness. Multiple logistic regression models of prevalent coronary heart disease and stroke that included the ultrasound findings indicated, after adjustment for age and sex, that maximum internal wall thickness and maximum common carotid wall thickness were significant correlates of both. Maximum stenosis did not add significantly to the correlation.

CONCLUSIONS

In the elderly the incidence of carotid atherosclerosis was high, although the frequency of severe disease was low. The prevalence and severity of carotid atherosclerosis continued to increase with age even in the late decades of life, and more disease was found in men than in women at all ages. Known risk factors for atherosclerosis continued to relate to carotid abnormalities in the later decades of life, both in symptomatic and asymptomatic subjects.