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Biomedical subjects

L E Hebert

Publications and source records attributed to L E Hebert.

At least 19 recordsLinked to original sources
PubMed2004

Blood pressure and late-life cognitive function change: a biracial longitudinal population study.

OBJECTIVE: To examine the relation of blood pressure (BP) to subsequent decline in cognitive function among persons age 65 or over. METHODS: All persons age 65 or over in a geographically defined community were invited to participate in a longitudinal study of problems of the elderly. Interviews were conducted in the participants' homes and included two BP measures and four tests of cognitive function. Follow-up interviews 3 and 6 years after baseline repeated the cognitive function tests. These analyses included 4,284 individuals who had baseline and at least one follow-up measure of cognitive function. The average of z scores of the individual cognitive function tests was used as a global measure of cognitive function. RESULTS: In random effects analyses controlling for age, sex, education, and race, there was no significant linear association of either systolic or diastolic BP with 6-year change in global cognitive function score. There was no significant curvilinear association with systolic BP. In tests for a curvilinear association with diastolic BP, there was a suggestion of increased decline among those with low or high diastolic BP (p = 0.03 for the quadratic diastolic term). At baseline, 50% of participants took some type of medication affecting BP. CONCLUSION: In this community population where BP treatment was common, there was no association of either high systolic or high diastolic BP at the beginning of the observation interval with 6-year cognitive decline.

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PubMed2004

Dietary niacin and the risk of incident Alzheimer's disease and of cognitive decline.

BACKGROUND: Dementia can be caused by severe niacin insufficiency, but it is unknown whether variation in intake of niacin in the usual diet is linked to neurodegenerative decline. We examined whether dietary intake of niacin was associated with incident Alzheimer's disease (AD) and cognitive decline in a large, prospective study. METHODS: This study was conducted in 1993-2002 in a geographically defined Chicago community of 6158 residents aged 65 years and older. Nutrient intake was determined by food frequency questionnaire. Four cognitive tests were administered to all study participants at 3 year intervals in a 6 year follow up. A total of 3718 participants had dietary data and at least two cognitive assessments for analyses of cognitive change over a median 5.5 years. Clinical evaluations were performed on a stratified random sample of 815 participants initially unaffected by AD, and 131 participants were diagnosed with 4 year incident AD by standardised criteria. RESULTS: Energy adjusted niacin intake had a protective effect on development of AD and cognitive decline. In a logistic regression model, relative risks (95% confidence intervals) for incident AD from lowest to highest quintiles of total niacin intake were: 1.0 (referent) 0.3 (0.1 to 0.6), 0.3 (0.1 to 0.7), 0.6 (0.3 to 1.3), and 0.3 (0.1 to 0.7) adjusted for age, sex, race, education, and ApoE e4 status. Niacin intake from foods was also inversely associated with AD (p for linear trend = 0.002 in the adjusted model). In an adjusted random effects model, higher food intake of niacin was associated with a slower annual rate of cognitive decline, by 0.019 standardised units (SU) per natural log increase in intake (mg) (p = 0.05). Stronger associations were observed in analyses that excluded participants with a history of cardiovascular disease (beta = 0.028 SU/year; p = 0.008), those with low baseline cognitive scores (beta = 0.023 SU/year; p = 0.02), or those with fewer than 12 years' education (beta = 0.035 SU/year; p = 0.002) CONCLUSION: Dietary niacin may protect against AD and age related cognitive decline.

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PubMed2001

Is the risk of developing Alzheimer's disease greater for women than for men?

A large proportion of people with Alzheimer's disease (AD) are women; however, it is not clear whether this is due to higher risk of disease or solely to the larger number of women alive at ages when AD is common. Beginning in 1982, two stratified random samples of people aged > or =65 years in East Boston, Massachusetts underwent detailed, structured clinical evaluation for prevalent (467 people) and incident (642 people from a cohort previously ascertained to be disease-free) probable AD. The prevalence sample was followed for mortality for up to 11 years (through December 1992). The age-specific incidence of AD did not differ significantly by sex (for men vs. women, odds ratio = 0.92; 95% confidence interval (CI): 0.51, 1.67). Controlled for age, prevalence also did not differ significantly by sex (for men vs. women, odds ratio = 1.29; 95% CI: 0.67, 2.48). The increase in risk of mortality due to AD did not vary by sex. The odds ratio for women with AD compared with women without AD was 2.07 (95% CI: 1.21, 3.56). For men, the odds ratio was 2.22 (95% CI: 1.02, 4.81). These findings suggest that the excess number of women with AD is due to the longer life expectancy of women rather than sex-specific risk factors for the disease.

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PubMed2001

Association of incident Alzheimer disease and blood pressure measured from 13 years before to 2 years after diagnosis in a large community study.

BACKGROUND: It is uncertain whether high blood pressure increases the risk of developing Alzheimer disease (AD). OBJECTIVE: To examine the association between incident AD and blood pressure measured up to 13 years before diagnosis. DESIGN: Longitudinal cohort study conducted from 1982 to 1988, with blood pressure measured every 3 years in home interviews, and in 1973 for a portion (60%) of the sample. SETTING: Community of East Boston, Mass. PARTICIPANTS: Six hundred thirty-four subjects 65 years or older and without AD were selected as a stratified random sample of participants of the East Boston Established Populations for Epidemiologic Studies of the Elderly. MAIN OUTCOME MEASURE: Alzheimer disease was diagnosed by a neurologist using a structured clinical evaluation. RESULTS: High blood pressure was not associated with an increased risk of AD in logistic regression models adjusted for age, sex, and level of education. There was no association with systolic pressure measured 13 years before diagnosis (odds ratio = 1.03/10 mm Hg; 95% confidence interval, 0.80-1.32) and an inverse association with systolic pressure measured 4 years before diagnosis (odds ratio = 0.82/10 mm Hg; 95% confidence interval, 0.72-0.95). Associations for diastolic pressure were in the same direction as those for systolic pressure except with wider confidence intervals. The odds ratios were not materially different with further adjustment for cardiovascular risk factors and diseases. CONCLUSION: In this large community study, high blood pressure was not associated with an increased risk of AD.

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PubMed2000

The cross-sectional association between blood pressure and Alzheimer's disease in a biracial community population of older persons.

BACKGROUND: The relation of blood pressure to Alzheimer's disease (AD) is complex because both an association of high blood pressure with increased risk of the disease and lower blood pressure as a consequence of the disease are possible. METHODS: We examined the cross-sectional association of blood pressure and AD in the Chicago Health and Aging Project (CHAP), a study of a geographically defined, biracial community. After in-home interviews with 6.162 residents > or =65 years, a stratified random sample of 729 participants was clinically evaluated; 709 had blood pressures measured, and 243 were diagnosed with AD. RESULTS: In logistic regression models adjusted for age, sex, education, and race there was no association between blood pressure measured as a continuous variable and Alzheimer's disease. In categorical analyses, however, prevalence of Alzheimer's disease was significantly higher among persons with low systolic pressure (<130 mmHg) compared with the referent group of 130-139 mmHg (odds ratio [OR] = 2.2, 95% confidence interval [CI]: 1.2,4.1), and with low diastolic pressure (<70 mmHg) compared to the referent of 70-79 mmHg (OR = 1.8, 95% CI: I. 1,3.1). High systolic and diastolic categories were not statistically different from the referent group, although there was some evidence that the associations differed by race. The odds ratios changed little with further adjustment for apolipoprotein E genotype, antihypertensive medications, body mass, stroke, diabetes, and heart disease. CONCLUSION: These findings are consistent with previous studies showing associations between low blood pressure and AD, but longitudinal studies are needed to characterize cause-and-effect associations.

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PubMed2000

Decline of language among women and men with Alzheimer's disease.

Previous research raises the possibility that gender differences occur in language function in Alzheimer's disease, but this hypothesis has not been evaluated systematically in longitudinal studies. The authors examined the association of gender with rate of decline in language and other cognitive functions among 410 persons with Alzheimer's disease. Participants were recruited from a dementia clinic and followed for up to 5 annual evaluations. Follow-up participation among survivors exceeded 90%. Decline in a composite score based on 8 language tests was evaluated in random effects models with age, education, and race controlled. Annual decline was 0.71 standard units (95% confidence interval [CI] = 0.62-0.79) for women and 0.74 units (95% CI = 0.61-0.86) for men, not a significant difference. Decline on the individual language tests and on composite measures of memory, perception, and global cognition also indicated no significant association with gender. These results suggest that Alzheimer's disease affects language and other cognitive functions similarly in women and men.

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PubMed2000

Comparison of informal caregiving by black and white older adults in a community population.

OBJECTIVES: To examine the prevalence of informal caregiving and demographic factors associated with caregiving time in older community residents and compare caregiving prevalence and time spent providing care by black and white residents. DESIGN: A cross-sectional, population-based study. SETTING: The study was conducted as part of the Chicago Health and Aging Project (CHAP) in a geographically defined community of black and white residents aged 65 and older. PARTICIPANTS: Participants were 5,924 community residents (61.4% black; 38.6% white) who answered questions about informal caregiving responsibilities during a structured interview about a broad range of health and social factors. METHODS: Data were collected during an in-home interview. Multiple logistic and linear regression models were used to examine the association between caregiving and race, gender, age, marital status, and education. RESULTS: More than 16% of residents had provided care to others during the previous 12 months, and 10.3% were currently providing care. Compared with whites, blacks were 30% more likely to be caregivers, spent almost 13 more hours each week in caregiving activities, and were more likely to assist friends. The probability of caregiving increased significantly with age for married persons, decreased with age for unmarried persons, and was lower for men compared with women. The time spent providing care each week increased significantly with age for married persons and did not differ between men and women. CONCLUSIONS: Although physicians and other healthcare providers typically view older people as the recipients of informal care, individuals older than age 65 provide a substantial amount of care to others with health problems and disability. Most research has focused on the needs of young and middle-aged caregivers, and little is known about the needs of these older caregivers. Future research should use sampling strategies that provide adequate numbers of white and non-white participants for meaningful comparisons. This will permit identification of racial and cultural differences in caregiving so that interventions can be tailored to specific groups.

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PubMed1999

Methodological issues in the study of cognitive decline.

In recent years, epidemiologists have given increased attention to cognition, especially to the dementing illnesses that occur in old age. Central to this study is the measurement of change in cognition as opposed to cognition measured at a single point in time. This article addresses conceptual and methodological issues in the study of changes in cognitive function, including: 1) difficulties encountered with the use of single measurements of cognition and the importance of measuring changes in cognition; 2) sources of measurement variation and its potential effects; 3) the importance of careful modeling of age and education; 4) considerations in categorizing outcomes or combining the results of cognitive tests; and 5) the benefits of using multiple-outcome statistical models.

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PubMed1999

Current and remote blood pressure and cognitive decline.

CONTEXT: Previous studies raise the possibility that blood pressure (BP) in middle age predicts later cognitive decline. OBJECTIVE: To examine prospectively the relationship of BP with level of and change in cognitive function in the elderly. DESIGN: Longitudinal, population-based study comprising subjects enrolled in the East Boston component of the Established Populations for the Epidemiologic Study of the Elderly (EPESE) (1982-1983) and the Hypertension Detection and Follow-Up Program (HDFP) (1973-1974). SETTING: East Boston, Mass. PARTICIPANTS: Of the 3657 participants in the EPESE with baseline BP measurements, 2068 also participated in the HDFP. Subjects were aged 65 to 102 years at baseline in the EPESE and had mental status and memory assessed at baseline and 3 and 6 years. MAIN OUTCOME MEASURES: Numbers of errors on the Short Portable Mental Status Questionnaire and the East Boston Memory Test and rates of change in these numbers of errors. Subjects had BP measured both at baseline in the EPESE and 9 years before, as part of the HDFP. RESULTS: In analyses adjusted for age, sex, and education, there was no strong linear association between BP and cognition. The associations found were fairly small in magnitude, and varied according to which test was used to measure cognition. There was little evidence for an effect of BP on change in cognitive function with either test, or for an effect on level of function on the memory test. In analyses of level of mental status questionnaire performance, however, elevated systolic BP (> or =160 mm Hg) 9 years before baseline was associated with a 14% (95% confidence interval [CI], 4%-25%) increase in error rate, relative to the referent (130-139 mm Hg). Baseline systolic BP had a U-shaped association with the number of errors; error rates were 9% higher compared with the referent group among those with systolic BP lower than 130 mm Hg (95% CI, 1%-17%) and 7% greater (95% CI, 0%-15%) among those with elevated systolic BP. Diastolic BP 9 years before baseline also had a U-shaped association with errors on the mental status questionnaire. CONCLUSION: The findings do not suggest a linear association of BP with cognitive decline, but they are consistent with a more complex relationship between BP and cognition than previously appreciated.

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PubMed1998

Vitamin E and vitamin C supplement use and risk of incident Alzheimer disease.

Oxidative stress may play a role in neurologic disease. The present study examined the relation between use of vitamin E and vitamin C and incident Alzheimer disease in a prospective study of 633 persons 65 years and older. A stratified random sample was selected from a disease-free population. At baseline, all vitamin supplements taken in the previous 2 weeks were identified by direct inspection. After an average follow-up period of 4.3 years, 91 of the sample participants with vitamin information met accepted criteria for the clinical diagnosis of Alzheimer disease. None of the 27 vitamin E supplement users had Alzheimer disease compared with 3.9 predicted based on the crude observed incidence among nonusers (p = 0.04) and 2.5 predicted based on age, sex, years of education, and length of follow-up interval (p = 0.23). None of the 23 vitamin C supplement users had Alzheimer disease compared with 3.3 predicted based on the crude observed incidence among nonusers (p = 0.10) and 3.2 predicted adjusted for age, sex, education, and follow-up interval (p = 0.04). There was no relation between Alzheimer disease and use of multivitamins. These data suggest that use of the higher-dose vitamin E and vitamin C supplements may lower the risk of Alzheimer disease.

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PubMed1997

Education and other measures of socioeconomic status and risk of incident Alzheimer disease in a defined population of older persons.

OBJECTIVE: To assess the relations of 3 measures of socioeconomic status (education, occupational prestige, and income) to risk of incident clinically diagnosed Alzheimer disease (AD). DESIGN: Cohort study with an average observation of 4.3 years. SETTING: East Boston, Mass. a geographically defined community. PARTICIPANTS: A stratified random sample of 642 community residents 65 years of age and older who were free of AD at baseline. MAIN OUTCOME MEASURE: Clinical diagnosis of probable AD according to standard criteria, using structured uniform evaluation. RESULTS: The relations of the 3 measures of socioeconomic status to risk of disease were assessed using logistic regression analyses. In individual analyses, fewer years of formal schooling, lower income, and lower occupational status each predicted risk of incident AD; risk of disease decreased by approximately 17% for each year of education. In an analysis including all 3 measures, the effect of education on risk for disease remained approximately the same, but the effects of the other 2 measures were somewhat less and did not attain formal statistical significance, compared with separate analysis of each measure. CONCLUSIONS: Markers of lower socioeconomic status predict risk of developing incident AD. The mechanism of this relation is uncertain, but the possibility that it reflects unidentified and potentially reversible risk factors for the disease deserves careful investigation.

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PubMed1997

Concordance between direct observation and staff rating of behavior in nursing home residents with Alzheimer's disease.

This study examined concordance between staff ratings and direct observations of behavior in 177 nursing home residents with Alzheimer's disease. During a structured interview, the staff member who had the most frequent contact with each resident completed three standardized behavioral rating scales. Direct observation of behavior (60 observations per resident) was conducted concurrently by trained nonparticipant observers using a structured time-sampling technique. We found moderate agreement between the two sources for the occurrence of 12 target behaviors during the monitoring period, but generally low agreement regarding the frequency of these behaviors. Discrepancies regarding occurrence of behavior were non-random with a higher rate of detection by direct observation. Thus, the practical advantages of staff ratings of behavior in institutional settings may be partly offset by some reduction in the accuracy of enumeration.

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PubMed1997

Why Alzheimer's disease is a women's health issue.

Alzheimer's disease is not typically included on the list of important women's health issues. Yet Alzheimer's disease is indeed a women's disease. Not only do more women than men have Alzheimer's disease, but women also provide a disproportionate amount of the informal community care for people with the disease. The prevalence of Alzheimer's disease increases dramatically with age and is highest among those 85 years of age and older. Women make up 72% of the US population over age 85 and, therefore, are the group most affected by the disease. By the year 2050, the number of people with Alzheimer's disease will more than double from approximately 4 million to 10 million, and 70% of these people will be age 85 or older. Although the symptoms and course of Alzheimer's disease may be similar in women and men, social and economic factors may produce a greater burden of disease among women, particularly with respect to the types and quality of health care services they receive, because women generally have the most limited social and financial resources. As the population ages, typical patients with Alzheimer's disease will be much older, frailer, and will have more functional impairments and chronic diseases than the patients most physicians see today. Future research needs to focus on identifying modifiable risk factors and effective treatments for Alzheimer's disease, and on determining the appropriate types of community-based and institutional services required to care for those with the illness as well as their families.

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PubMed1995

Age-specific incidence of Alzheimer's disease in a community population.

OBJECTIVE: To determine age-specific incidence rates of clinically diagnosed Alzheimer's disease. DESIGN: Cohort, followed a mean of 4.3 years. SETTING: East Boston, Mass. PARTICIPANTS: Of 2313 persons aged 65 years and older who were initially free of Alzheimer's disease, 1601 participated in the ascertainment of incident disease (80% of survivors), 409 declined participation, and 303 died before the end of the follow-up period. A stratified sample of 642 persons received detailed clinical evaluation. OUTCOME MEASURE: Diagnosis of new probable Alzheimer's disease through structured clinical evaluation including neurologic, neuropsychological, and psychiatric examination. Community incidence rates were computed by 5-year age groups, adjusted for gender, single year of age, length of follow-up interval, and sampling design. RESULTS: The estimated annual incidence of Alzheimer's disease in the population was 0.6% (95% confidence interval [CI], 0.3% to 0.9%) for persons aged 65 to 69 years, 1.0% (95% CI, 0.6% to 1.4%) for persons aged 70 to 74 years, 2.0% (95% CI, 1.3% to 2.7%) for persons aged 75 to 79 years, 3.3% (95% CI, 2.2% to 4.4%) for persons aged 80 to 84 years, and 8.4% (95% CI, 3.7% to 13.1%) for persons aged 85 years and older. CONCLUSIONS: The incidence of Alzheimer's disease is substantial and is approximately 14 times higher among persons older than 85 years compared with those between 65 and 69 years of age.

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PubMed1993

Relationship between malpractice claims and cesarean delivery.

OBJECTIVE: To investigate whether an association exists between the probability of a cesarean delivery and the level of malpractice claims risk faced by hospitals and physicians. DESIGN: Survey of computerized discharge data linked with physician and hospital malpractice claims records based on stratified, random sample of hospitals. SETTING: Acute care hospitals in New York State in 1984. POPULATION: All deliveries (60 490) at 31 hospitals. RESULTS: After controlling for the clinical risk of a cesarean delivery, patient socioeconomic status, and physician and hospital characteristics, cesarean delivery was positively associated with physician malpractice premiums (odds ratio [OR], 3.00; 95% confidence interval [CI], 2.13 to 4.24 for the difference between upstate and New York City levels), with the number of physician claims opened per 100 physicians at the hospital level (OR, 1.15; 95% CI, 1.02 to 1.30 for a 1-SD change), and with the number of hospital claims opened per 1000 discharges (OR, 1.26; 95% CI, 1.10 to 1.43 for a 1-SD change). Measures of physician-perceived risk of suit also showed a significant association with cesarean delivery (OR, 1.96; 95% CI, 1.53 to 2.52, upstate vs New York City). Within hospitals, there was no significant association (OR, 1.15; P = .126) between the odds of cesarean delivery and the claims history (none vs one or more) of an individual physician. CONCLUSION: Results support previous speculations of a positive association between malpractice claims risk and the rate of cesarean delivery.

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PubMed1993

Level of education and change in cognitive function in a community population of older persons.

In a community population of persons over the age of 65, cognitive function was assessed using brief performance tests on two occasions 3 years apart. Those with fewer years of formal education consistently had greater declines in cognitive function, independently of age, birthplace, language of interview, occupation, and income. These prospective findings suggest that low educational attainment or a correlate predicts cognitive decline. It is not clear, however, whether this relation represents a direct effect of education on future cognition, whether education might be related to occurrence of a disease leading to cognitive decline in older persons, or whether education might be a surrogate for some variable not included in the study.

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PubMed1992

Relation of smoking and alcohol consumption to incident Alzheimer's disease.

The authors examined the effects of smoking and alcohol use in a prospective community-based study of incident Alzheimer's disease. Two in-home interviews of the total elderly population of East Boston, Massachusetts, conducted in 1982 and 1985 were used to sample individuals for clinical evaluation for Alzheimer's disease. A total of 513 persons underwent detailed clinical evaluation including neurologic, neuropsychologic, and psychiatric evaluation to diagnose Alzheimer's disease. In weighted logistic regression controlled for age, sex, and education, the estimated odds ratio of Alzheimer's disease was 0.7 (95% confidence interval 0.3-1.4) for ever smokers compared with never smokers. For 40 pack-years of smoking, the odds ratio of Alzheimer's disease was 0.8 (95% confidence interval 0.6-1.1). Consumption of 1 oz (30 ml) of alcohol per day was associated with an odds ratio of 1.1 (95% confidence interval 0.8-1.5). These results suggest that recent mild-to-moderate consumption of alcohol is not substantially related to incidence of Alzheimer's disease and that smoking does not increase risk of the disease.

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