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Biomedical subjects

S J Kittner

Publications and source records attributed to S J Kittner.

At least 19 recordsLinked to original sources
PubMed1996

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.

Cerebral Hemorrhage↗
PubMed1996

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.

Anticoagulants↗
PubMed1996

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.

Adolescent↗
PubMed1996

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.

Adult↗
PubMed1995

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.

Adult↗
PubMed1995

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.

Aged↗
PubMed1995

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.

Adolescent↗
PubMed1995

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)

Aged↗
PubMed1995

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.

Adolescent↗
PubMed1995

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.

Adult↗
PubMed1994

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.

Aged↗
PubMed1994

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.

Age Factors↗
PubMed1993

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.

Aged↗
PubMed1993

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.

Adolescent↗
PubMed1992

Orthostatic hypotension in older adults. The Cardiovascular Health Study. CHS Collaborative Research Group.

The purpose of the present study was to assess the prevalence of orthostatic hypotension and its associations with demographic characteristics, cardiovascular risk factors and symptomatology, prevalent cardiovascular disease, and selected clinical measurements in the Cardiovascular Health Study, a multicenter, observational, longitudinal study enrolling 5,201 men and women aged 65 years and older at initial examination. Blood pressure measurements were obtained with the subjects in a supine position and after they had been standing for 3 minutes. The prevalence of asymptomatic orthostatic hypotension, defined as 20 mm Hg or greater decrease in systolic or 10 mm Hg or greater decrease in diastolic blood pressure, was 16.2%. This prevalence increased to 18.2% when the definition also included those in whom the procedure was aborted due to dizziness upon standing. The prevalence was higher at successive ages. Orthostatic hypotension was associated significantly with difficulty walking (odds ratio, 1.23; 95% confidence interval, 1.02, 1.46), frequent falls (odds ratio, 1.52; confidence interval, 1.04, 2.22), and histories of myocardial infarction (odds ratio, 1.24; confidence interval, 1.02, 1.50) and transient ischemic attacks (odds ratio, 1.68; confidence interval, 1.12, 2.51). History of stroke, angina pectoris, and diabetes mellitus were not associated significantly with orthostatic hypotension. In addition, orthostatic hypotension was associated with isolated systolic hypertension (odds ratio, 1.35; confidence interval, 1.09, 1.68), major electrocardiographic abnormalities (odds ratio, 1.21; confidence interval, 1.03, 1.42), and the presence of carotid artery stenosis based on ultrasonography (odds ratio, 1.67; confidence interval, 1.23, 2.26). Orthostatic hypotension was negatively associated with weight. We conclude that orthostatic hypotension is common in the elderly and increases with advancing age. It is associated with cardiovascular disease, particularly those manifestations measured objectively, such as carotid stenosis. It is associated also with general neurological symptoms, but this link may not be causal. Differences in prevalence of and associations with orthostatic hypotension in the present study compared with others are largely attributed to differences in population characteristics and methodology.

Aged↗