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Articles by Kenneth M. Langa
Total Records ( 9 ) for Kenneth M. Langa
  Kala M. Mehta , Anita L. Stewart , Kenneth M. Langa , Kristine Yaffe , Sandra Moody- Ayers , Brie A. Williams and Kenneth E. Covinsky
  Background A low level of formal education is becoming accepted as a risk factor for Alzheimer's disease (AD). Although increasing attention has been paid to differences in educational quality, no previous studies addressed participants' own characterizations of their overall performance in school. We examined whether self-assessed school performance is associated with AD beyond the effects of educational level alone. Methods Participants were drawn from the population-representative Aging, Demographics, and Memory Study (ADAMS, 2000-2002). The ADAMS participants were asked about their performance in school. Possible response options included “above average” “average,” or “below average.” The ADAMS participants also underwent a full neuropsychological battery, and received a research diagnosis of possible or probable AD. Results The 725 participants (mean age, 81.8 years; 59% female; 16% African-American) varied in self-assessed educational performance: 29% reported “above average,” 64% reported “average,” and 7% reported “below average” school performance. Participants with a lower self-assessed school performance had higher proportions of AD: 11% of participants with “above average” self-assessed performance had AD, as opposed to 12% of participants with “average” performance and 26% of participants with “below average” performance (P < 0.001). After controlling for subjects' years in school, a literacy test score (Wide-Range Achievement Test), age, sex, race/ethnicity, apolipoprotein E-ɛ4 status, socioeconomic status, and self-reported comorbidities, respondents with “below average” self-assessed school performance were four times more likely to have AD compared with those of “average” performance (odds ratio, 4.0; 95% confidence interval, 1.2–14). “Above average” and “average” self-assessed school performance did not increase or decrease the odds of having AD (odds ratio, 0.9; 95% confidence interval, 0.5–1.7). Conclusions We suggest an association between “below average” self-assessed school performance and AD beyond the known association with formal education. Efforts to increase cognitive reserve through better school performance, in addition to increasing the number of years of formal education in early life, may be important in reducing vulnerability throughout the life course.
  Guy G. Potter , Brenda L. Plassman , Brenda L. Plassman , Mohammed U. Kabeto , Kenneth M. Langa , David J. Llewellyn , Mary A.M. Rogers and David C. Steffens
  Background The diagnosis of cognitive impairment and dementia must reflect an increasingly diverse and aging United States population. This study compared direct testing and informant reports of cognition with clinical diagnoses of cognitive impairment and dementia between African Americans and whites. Methods Participants in the Aging, Demographics, and Memory Study completed in-person dementia evaluations, and were assigned clinical diagnoses (by a consensus panel of dementia experts) of normal; cognitive impairment, not demented (CIND); and dementia. The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) total score and the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) were used to assess cognitive performance and reported cognitive decline. Results A higher CERAD total score was associated with lower odds of CIND and dementia, at comparable ratios between African Americans and whites. Higher IQCODE scores were associated with increased odds of dementia in both African Americans and whites. Higher IQCODE scores were associated with increased odds of CIND among whites, but not among African Americans. Conclusions Cultural differences may influence informant reports of prevalent CIND and dementia. Our findings also highlight the need for more comparative research to establish the cultural validity of measures used to diagnose these conditions.
  Sudha Seshadri , Alexa Beiser , Rhoda Au , Philip A. Wolf , Denis A. Evans , Robert S. Wilson , Ronald C. Petersen , Ronald C. Petersen , Walter A. Rocca , Claudia H. Kawas , Maria M. Corrada , Brenda L. Plassman , Kenneth M. Langa and Helena C. Chui
  This article focuses on the effects of operational differences in case ascertainment on estimates of prevalence and incidence of cognitive impairment and/or dementia of the Alzheimer type. Experience and insights are discussed by investigators from the Framingham Heart Study, the East Boston Senior Health Project, the Chicago Health and Aging Project, the Mayo Clinic Study of Aging, the Baltimore Longitudinal Study of Aging, and the Aging, Demographics, and Memory Study. There is a general consensus that the single most important factor determining prevalence estimates of Alzheimer‘s disease (AD) is the severity of cognitive impairment used as a threshold to define cases. Studies that require a level of cognitive impairment in which persons are unable to provide self-care will have much lower estimates than the studies aimed at identifying persons in the earliest stages of AD. There are limited autopsy data from the aforementioned epidemiological studies to address accuracy in the diagnosis of etiological subtype, namely the specification of AD alone or in combination with other types of pathology. However, other community-based cohort studies show that many persons with mild cognitive impairment and also some persons without dementia or mild cognitive impairment meet pathological criteria for AD, thereby suggesting that the number of persons who would benefit from an effective secondary prevention intervention is probably higher than the published prevalence estimates. Improved accuracy in the clinical diagnosis of AD is anticipated with the addition of molecular and structural biomarkers in the next generation of epidemiological studies.
  Ron Brookmeyer , Denis A. Evans , Liesi Hebert , Kenneth M. Langa , Steven G. Heeringa , Brenda L. Plassman and Walter A. Kukull
  Several methods of estimating prevalence of dementia are presented in this article. For both Brookmeyer and the Chicago Health and Aging project (CHAP), the estimates of prevalence are derived statistically, forward calculating from incidence and survival figures. The choice of incidence rates on which to build the estimates may be critical. Brookmeyer used incidence rates from several published studies, whereas the CHAP investigators applied the incidence rates observed in their own cohort. The Aging, Demographics, and Memory Study (ADAMS) and the East Boston Senior Health Project (EBSHP) were sample surveys designed to ascertain the prevalence of Alzheimer‘s disease and dementia. ADAMS obtained direct estimates by relying on probability sampling nationwide. EBSHP relied on projection of localized prevalence estimates to the national population. The sampling techniques of ADAMS and EBSHP were rather similar, whereas their disease definitions were not. By contrast, EBSPH and CHAP have similar disease definitions internally, but use different calculation techniques, and yet arrive at similar prevalence estimates, which are considerably greater than those obtained by either Brookmeyer or ADAMS. Choice of disease definition may play the larger role in explaining differences in observed prevalence between these studies.
  Robert S. Wilson , David R. Weir , Sue E. Leurgans , Denis A. Evans , Liesi E. Hebert , Kenneth M. Langa , Brenda L. Plassman , Brent J. Small and David A. Bennett
  Background The prevalence of Alzheimer‘s disease (AD) in the United States was estimated at 2.3 million in 2002 by the Aging, Demographics, and Memory Study (ADAMS), which is almost 50% less than the estimate of 4.5 million in 2000 derived from the Chicago Health and Aging Project. Methods We considered how differences in diagnostic criteria may have contributed to these differences in AD prevalence. Results We identified several important differences in diagnostic criteria that may have contributed to the differing estimates of AD prevalence. Two factors were especially noteworthy. First, the Diagnostic and Statistical Manual of Mental Disorders III-R and IV criteria of functional limitation documented by an informant used in ADAMS effectively concentrated the diagnosis of dementia toward a relatively higher level of cognitive impairment. ADAMS separately identified a category of cognitive impairment not dementia and within that group there were a substantial number of cases with ”prodromal“ AD (a maximum of 1.95 million with upweighting). Second, a substantial proportion of dementia in ADAMS was attributed to either vascular disease (representing a maximum of 0.59 million with upweighting) or undetermined etiology (a maximum of 0.34 million), whereas most dementia, including mixed dementia, was attributed to AD in the Chicago Health and Aging Project. Conclusion The diagnosis of AD in population studies is a complex process. When a diagnosis of AD excludes persons meeting criteria for vascular dementia, when not all persons with dementia are assigned an etiology, and when a diagnosis of dementia requires an informant report of functional limitations, the prevalence is substantially lower and the diagnosed cases most likely have a relatively higher level of impairment.
  Walter A. Rocca , Ronald C. Petersen , David S. Knopman , Liesi E. Hebert , Denis A. Evans , Kathleen S. Hall , Sujuan Gao , Frederick W. Unverzagt , Kenneth M. Langa , Eric B. Larson and Lon R. White
  Declines in heart disease and stroke mortality rates are conventionally attributed to reductions in cigarette smoking, recognition and treatment of hypertension and diabetes, effective medications to improve serum lipid levels and to reduce clot formation, and general lifestyle improvements. Recent evidence implicates these and other cerebrovascular factors in the development of a substantial proportion of dementia cases. Analyses were undertaken to determine whether corresponding declines in age-specific prevalence and incidence rates for dementia and cognitive impairment have occurred in recent years. Data spanning 1 or 2 decades were examined from community-based epidemiological studies in Minnesota, Illinois, and Indiana, and from the Health and Retirement Study, which is a national survey. Although some decline was observed in the Minnesota cohort, no statistically significant trends were apparent in the community studies. A significant reduction in cognitive impairment measured by neuropsychological testing was identified in the national survey. Cautious optimism appears justified.
  David R. Weir , Robert B. Wallace , Kenneth M. Langa , Brenda L. Plassman , Robert S. Wilson , David A. Bennett , Ranjan Duara , David Loewenstein , Mary Ganguli and Mary Sano
  Establishing methods for ascertainment of dementia and cognitive impairment that are accurate and also cost-effective is a challenging enterprise. Large population-based studies often using administrative data sets offer relatively inexpensive and reliable estimates of severe conditions including moderate to advanced dementia that are useful for public health planning, but they can miss less severe cognitive impairment which may be the most effective point for intervention. Clinical and epidemiological cohorts, intensively assessed, provide more sensitive detection of less severe cognitive impairment but are often costly. In this article, several approaches to ascertainment are evaluated for validity, reliability, and cost. In particular, the methods of ascertainment from the Health and Retirement Study are described briefly, along with those of the Aging, Demographics, and Memory Study (ADAMS). ADAMS, a resource-intense sub-study of the Health and Retirement Study, was designed to provide diagnostic accuracy among persons with more advanced dementia. A proposal to streamline future ADAMS assessments is offered. Also considered are algorithmic and Web-based approaches to diagnosis that can reduce the expense of clinical expertise and, in some contexts, can reduce the extent of data collection. These approaches are intended for intensively assessed epidemiological cohorts where goal is valid and reliable case detection with efficient and cost-effective tools.
  Mary D. Naylor , Jason H. Karlawish , Steven E. Arnold , Ara S. Khachaturian , Zaven S. Khachaturian , Virginia M.-Y. Lee , Matthew Baumgart , Sube Banerjee , Cornelia Beck , Kaj Blennow , Ron Brookmeyer , Kurt R. Brunden , Kathleen C. Buckwalter , Meryl Comer , Kenneth Covinsky , Lynn Friss Feinberg , Giovanni Frisoni , Colin Green , Renato Maia Guimaraes , Lisa P. Gwyther , Franz F. Hefti , Michael Hutton , Claudia Kawas , David M. Kent , Lewis Kuller , Kenneth M. Langa , Robert W. Mahley , Katie Maslow , Colin L. Masters , Diane E. Meier , Peter J. Neumann , Steven M. Paul , Ronald C. Petersen , Mark A. Sager , Mary Sano , Dale Schenk , Holly Soares , Reisa A. Sperling , Sidney M. Stahl , Vivianna van Deerlin , Yaakov Stern , David Weir , David A. Wolk and John Q. Trojanowski
  To address the pending public health crisis due to Alzheimer‘s disease (AD) and related neurodegenerative disorders, the Marian S. Ware Alzheimer Program at the University of Pennsylvania held a meeting entitled "State of the Science Conference on the Advancement of Alzheimer's Diagnosis, Treatment and Care," on June 21-22, 2012. The meeting comprised four workgroups focusing on Biomarkers; Clinical Care and Health Services Research; Drug Development; and Health Economics, Policy, and Ethics. The workgroups shared, discussed, and compiled an integrated set of priorities, recommendations, and action plans, which are presented in this article.
  Adeline Delavande , Michael D. Hurd , Paco Martorell and Kenneth M. Langa
  Background High levels of out-of-pocket (OOP) spending for health care may lead patients to forego needed services and medications as well as hamper their ability to pay for other essential goods. Because it leads to disability and the loss of independence, dementia may put patients and their families at risk for high OOP spending, especially for long-term care services. Methods We used data from the Aging, Demographics, and Memory Study, a nationally representative subsample (n = 743) of the Health and Retirement Study, to determine whether individuals with dementia had higher self-reported OOP spending compared with those with cognitive impairment without dementia and those with normal cognitive function. We also examined the relationship between dementia and utilization of dental care and prescription medications–two types of health care that are frequently paid for OOP. Multivariate and logistic regression models were used to adjust for the influence of potential confounders. Results After controlling for demographics and comorbidities, those with dementia had more than three times the yearly OOP spending compared with those with normal cognition ($8216 for those with dementia vs. $2570 for those with normal cognition, P < .01). Higher OOP spending for those with dementia was mainly driven by greater expenditures on nursing home care (P < .01). Dementia was not associated with the likelihood of visiting the dentist (P = .76) or foregoing prescription medications owing to cost (P = .34). Conclusions Dementia is associated with high levels of OOP spending but not with the use of dental care or foregoing prescription medications, suggesting that excess OOP spending among those with dementia does not ”crowd out“ spending on these other health care services.
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