Biomedical subjects

Brenda L Plassman

Publications and source records attributed to Brenda L Plassman.

9 recordsLinked to original sources

PubMed2006

Vascular risk factors and cognitive decline among elderly male twins.

BACKGROUND: Studies investigating the association between cardiovascular risk factors and cognitive decline report discrepant outcomes. The co-twin control method improves on traditional case-control approaches by controlling for within-twin pair similarities of genetic and early environmental influences. OBJECTIVE: To examine the association of diabetes, hypertension, hypercholesterolemia, and elevated body mass index (BMI) (>30 kg/m(2)), individually and combined, with cognitive decline over a 12-year period in members of the National Academy of Sciences-National Research Council Twin Registry of World War II male veterans. METHODS: Modified Telephone Interview for Cognitive Status (TICS-m) was administered four times at approximately 4-year intervals from 1990 to 2002 as part of an epidemiologic study of dementia. Self-report medical information was collected from 1996 to 2002. We examined the difference in cognitive decline within twin pairs discordant for the vascular risk factors while controlling for baseline TICS-m, education, smoking, and alcohol history. RESULTS: Among twin pairs discordant for diabetes (n = 177), the diabetic twins declined an average of almost 1 point more than their nondiabetic co-twins (p = 0.018) at the last screening time point. Further analyses showed that this was in large part due to greater decline among older men (age 76 to 84 years). Cognitive change was not significantly different between members of pairs discordant for hypertension (n = 326), hypercholesterolemia (n = 282), or elevated BMI (n = 166). CONCLUSION: Based on this study of twin pairs who share similar genetic and early environmental risks for cardiovascular risk factors, diabetes is associated with greater cognitive decline, particularly among the oldest individuals.

Age Factors↗

PubMed2005

The Aging, Demographics, and Memory Study: study design and methods.

OBJECTIVE: We describe the design and methods of the Aging, Demographics, and Memory Study (ADAMS), a new national study that will provide data on the antecedents, prevalence, outcomes, and costs of dementia and "cognitive impairment, not demented" (CIND) using a unique study design based on the nationally representative Health and Retirement Study (HRS). We also illustrate potential uses of the ADAMS data and provide information to interested researchers on obtaining ADAMS and HRS data. METHODS: The ADAMS is the first population-based study of dementia in the United States to include subjects from all regions of the country, while at the same time using a single standardized diagnostic protocol in a community-based sample. A sample of 856 individuals age 70 or older who were participants in the ongoing HRS received an extensive in-home clinical and neuropsychological assessment to determine a diagnosis of normal, CIND, or dementia. Within the CIND and dementia categories, subcategories (e.g. Alzheimer's disease, vascular dementia) were assigned to denote the etiology of cognitive impairment. CONCLUSION: Linking the ADAMS dementia clinical assessment data to the wealth of available longitudinal HRS data on health, health care utilization, informal care, and economic resources and behavior, will provide a unique opportunity to study the onset of CIND and dementia in a nationally representative population-based sample, as well as the risk factors, prevalence, outcomes, and costs of CIND and dementia.

Aging↗

PubMed2005

Verification of self-report of zygosity determined via DNA testing in a subset of the NAS-NRC twin registry 40 years later.

The National Academy of Sciences -- National Research Council (NAS-NRC) twin panel, created nearly 50 years ago, had twin zygosity determined primarily via a similarity questionnaire that has been estimated to correctly classify at least 95% of twins. In the course of a study on the genetics of healthy ageing in the NAS-NRC twins, DNA was collected for genome-wide scanning and zygosity confirmation was examined in 343 participating pairs. The sample was supplemented from two other studies using NAS-NRC twins where one or both co-twins were suspected to have Alzheimer disease or another dementia, or Parkinson's disease. Overall 578 twin pairs with DNA were analyzed. Zygosity assignment for 96.8% (519/536) was confirmed via questionnaire. Among 42 pairs whose questionnaire responses were inconclusive for assigning zygosity, 50% were found to be monozygous (MZ) and 50% were dizygous (DZ). There was some evidence for greater misclassification of presumed DZ pairs in the healthy ageing study where participation favored pairs who were similar in having a favorable health history and willingness to volunteer without any element of perceived risk for a specific disease influencing participation.

Adult↗

PubMed2004

A twin study of the genetic contribution to age-related functional impairment.

BACKGROUND: A key element in the quality of later life is the prevalence of age-related functional impairments. The objective of this study was to quantify the genetic and environmental influences on age-related functional impairment in a population of white male twin elders who were fit in young adulthood when entering military service. The extent of genetic influence on functioning in later life affects the role of public health, personal initiative, and service interventions. METHODS: Indicators of functional impairment were determined by telephone survey and by twin pair responses to 10 indicators of basic, instrumental, and social activities, and mobility. Responses were analyzed using structural equation modeling. Prevalence and concordances were determined by zygosity status. Covariance was partitioned between twins in a pair into components attributable to additive genetics, common environment, and unique environment. RESULTS: Data from 2721 twin pairs (1384 monozygotic and 1337 dizygotic) were analyzed for the 10 dichotomous indicators of functional impairment and for a subscale of 8 of these indicators. For the subscale, additive genes accounted for approximately 21% of covariance in liability for a higher score, whereas unique environment accounted for approximately 78% of variance, with age accounting for a very small proportion. In two indicators there were nontrivial effects of common environment. CONCLUSIONS: Within the expressed limits on generalization, the study findings suggest a major potential role for interventions aimed at a person's unique environment to maintain good functioning in aging and to lengthen the period of active life. Genetic effects play a modest but also important role in age-related functional impairment.

Activities of Daily Living↗

PubMed2004

Methodology and preliminary results from the neurocognitive outcomes of depression in the elderly study.

A methodology is presented for following a cohort of older depressed patients to examine neurocognitive outcomes of depression. A total of 265 depressed individuals and 138 healthy, nondepressed controls age 60 and older who completed at least 1 year of follow-up data underwent periodic clinical evaluation by a geriatric psychiatrist. A subset of 141 patients and 137 controls had neuropsychological testing. A consensus panel of experts reviewed 63 depressed subjects with suspected cognitive impairment. Twenty-seven individuals in the depressed group were assigned diagnoses of dementia, including 11 with Alzheimer's disease, 8 with vascular dementia, and 8 with dementia of undetermined etiology. In addition, 25 individuals had other forms of cognitive impairment, and 11 were considered cognitively normal. Among elderly controls, 2 developed substantial cognitive impairment with clinical diagnoses of dementia. Among the depressed group, the incidence rates for dementia for this age are much higher than would be expected. These results are consistent with prior evidence linking depression and later dementia. Future studies are needed to examine neuroimaging and genetic, clinical, and social predictors of neurocognitive decline in depression.

Aged↗

PubMed2002

Hormone replacement therapy and incidence of Alzheimer disease in older women: the Cache County Study.

CONTEXT: Previous studies have shown a sex-specific increased risk of Alzheimer disease (AD) in women older than 80 years. Basic neuroscience findings suggest that hormone replacement therapy (HRT) could reduce a woman's risk of AD. Epidemiologic findings on AD and HRT are mixed. OBJECTIVE: To examine the relationship between use of HRT and risk of AD among elderly women. DESIGN, SETTING, AND PARTICIPANTS: Prospective study of incident dementia among 1357 men (mean age, 73.2 years) and 1889 women (mean age, 74.5 years) residing in a single county in Utah. Participants were first assessed in 1995-1997, with follow-up conducted in 1998-2000. History of women's current and former use of HRT, as well as of calcium and multivitamin supplements, was ascertained at the initial contact. MAIN OUTCOME MEASURE: Diagnosis of incident AD. RESULTS: Thirty-five men (2.6%) and 88 women (4.7%) developed AD between the initial interview and time of the follow-up (3 years). Incidence among women increased after age 80 years and exceeded the risk among men of similar age (adjusted hazard ratio [HR], 2.11; 95% confidence interval [CI], 1.22-3.86). Women who used HRT had a reduced risk of AD (26 cases among 1066 women) compared with non-HRT users (58 cases among 800 women) (adjusted HR, 0.59; 95% CI, 0.36-0.96). Risk varied with duration of HRT use, so that a woman's sex-specific increase in risk disappeared entirely with more than 10 years of treatment (7 cases among 427 women). Adjusted HRs were 0.41 (95% CI, 0.17-0.86) for HRT users compared with nonusers and 0.77 (95% CI, 0.31-1.67) compared with men. No similar effect was seen with calcium or multivitamin use. Almost all of the HRT-related reduction in incidence reflected former use of HRT (9 cases among 490 women; adjusted HR, 0.33 [95% CI, 0.15-0.65]). There was no effect with current HRT use (17 cases among 576 women; adjusted HR, 1.08 [95% CI, 0.59-1.91]) unless duration of treatment exceeded 10 years (6 cases among 344 women; adjusted HR, 0.55 [95% CI, 0.21-1.23]). CONCLUSIONS: Prior HRT use is associated with reduced risk of AD, but there is no apparent benefit with current HRT use unless such use has exceeded 10 years.

Aged↗

PubMed2002

Head injury in early adulthood and the lifetime risk of depression.

BACKGROUND: Depressive symptoms are common and can be debilitating in the months after head injury. Head injury can also have long-term cognitive effects, but little is known about the long-term risk of depression associated with head injury. We investigated the lifetime rates of depressive illness 50 years after closed head injury. METHODS: Participants were male World War II veterans who served during 1944-1945 and were hospitalized at that time for a head injury, pneumonia, or laceration, puncture, or incision wounds. We used military medical records to establish the presence and severity of closed head injuries. Veterans with (n = 520) and without (n = 1198) head injuries were interviewed in 1996-1997 for their lifetime history of depressive illness. Men with dementia were excluded. RESULTS: Veterans with head injury were more likely to report major depression in subsequent years and were more often currently depressed. Using logistic regression and controlling for age and education, the lifetime prevalence of major depression in the head injured group was 18.5% vs 13.4% in those with no head injury (odds ratio = 1.54, 95% confidence interval = 1.17-2.04). Current major depression was detected in 11.2% of the veterans with head injuries vs 8.5% of those without head injury (odds ratio = 1.63, 95% confidence interval = 1.07-2.50). This increase in depression could not be explained by a history of myocardial infarction, a history of cerebrovascular accident, or history of alcohol abuse. The lifetime risk of depression increased with severity of the head injury. CONCLUSION: The risk of depression remains elevated for decades following head injury and seems to be highest in those who have had a severe head injury.

Adult↗

PubMed2002

An adaptation of the modified mini-mental state examination: analysis of demographic influences and normative data: the cache county study.

OBJECTIVES: To present a new version of the Modified Mini-Mental State Examination (3MS-R), provide normative information extending to individuals in the 10th decade, and examine the effects of demographic variables on test performance. BACKGROUND: The Modified Mini-Mental State Examination, based originally on the Mini-Mental State Examination, has been used to screen populations for dementia. Providing normative information and an analysis of demographic variables on test performance for this version would support broader use in clinical and other settings. METHODS: Two thousand, nine hundred thirteen elderly individuals determined to be free of dementia and other neurologic and psychiatric conditions served as subjects. An analysis of variance was conducted to examine the effects of age, gender, and education on test performance. Descriptive statistics (means, standard deviations, and percentile ranks) were calculated to summarize the range of normal performance. To examine the sensitivity/specificity of the suggested cut-off points at the 7th and 10th percentiles, two subsamples of elderly individuals, on whom clinical dementia assessments were available, were used to classify individuals with regard to dementia status. RESULTS: Lower age, higher education, and female gender were associated with higher 3MS-R scores. Gender effects were among the weakest, but most important at lower levels of education. Education effects were most prominent in the youngest age groups. Selection of a cut-off point at the 7th percentile revealed 69%-70% sensitivity for detecting dementia, and higher sensitivity for individuals in the youngest age groups. Specificity at this cut-off point was 89%. Raising the cut-off point to the 10th percentile improved sensitivity to 73%-76%, but reduced specificity to 85%-86%. CONCLUSION: We present a version of the Modified Mini-Mental State Examination that has demonstrated utility in screening a population for dementia. An analysis of normative information and the effects of demographic influences suggest that the 7th percentile cut-off point performs very well in detecting dementia in 65-79-year-old individuals but less well for individuals in their 80s and 90s. To increase the sensitivity of the 3MS-R to detect dementia or other forms of cognitive impairment, particularly among the "old-old," the test user may wish to raise the cut-off point for impairment in some demographic groups or to supplement the test with additional cognitive measures.

Aged↗

PubMedDate not supplied

Prevalence and clinical correlates of neuropsychiatric symptoms in dementia.

The purpose of this research was to assess the frequency and severity of neuropsychiatric and behavioral symptoms and to examine the association between preexisting medical conditions and specific neuropsychiatric symptoms in demented individuals. We studied 211 demented subjects (87.7 percent male) who were participants in epidemiological studies of dementia. Using the Neuropsychiatric Inventory (NPI), we assessed the frequency and severity of neuropsychiatric symptoms. We collected medical history information during a structured telephone interview. Our analyses focused on determining prevalence of neuropsychiatric symptoms by dementia diagnosis and severity. We also examined the association of history of head injury, alcohol abuse, and stroke with development of neuropsychiatric symptoms. We found that neuropsychiatric symptoms were common, with approximately three-fourths of the subjects exhibiting at least one symptom during the preceding month. Apathy (39.3 percent), agitation (31.8 percent), and aberrant motor behavior (31.1 percent) were the most frequent symptoms. Frequency and severity of symptoms were similar for the all-dementia and Alzheimer's disease-only groups, neuropsychiatric symptoms varied by severity of dementia, but generally not in a consistent ordinal pattern. History of alcohol abuse, head injury, or stroke was associated with presence of specific neuropsychiatric symptoms in dementia. While psychiatric symptoms are common in dementia, they also vary by type and severity of dementia. The finding that certain medical conditions may increase risk for specific types of neuropsychiatric symptoms expands our knowledge of the natural history of dementia and should improve management of dementia in medically ill patients. Our results may also shed light on mechanisms that underlie neuropsychiatric symptoms.

Aged↗