0
We're unable to sign you in at this time. Please try again in a few minutes.
Retry
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
Retry
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Original Contribution |

The Influence of Education on Clinically Diagnosed Dementia Incidence and Mortality Data From the Kungsholmen Project FREE

Chengxuan Qiu, MD, PhD; Lars Bäckman, MD, PhD; Bengt Winblad, MD, PhD; Hedda Agüero-Torres, MD, PhD; Laura Fratiglioni, MD, PhD
[+] Author Affiliations

From the Aging Research Center, Division of Geriatric Epidemiology, Department of Clinical Neuroscience, Occupational Therapy, and Elderly Care Research, Karolinska Institutet and Stockholm Gerontology Research Center, Stockholm, Sweden (Drs Qiu, Bäckman, Winblad, Agüero-Torres, and Fratiglioni); and the Department of Psychology, Uppsala University, Uppsala, Sweden (Dr Bäckman).


Arch Neurol. 2001;58(12):2034-2039. doi:10.1001/archneur.58.12.2034.
Text Size: A A A
Published online

Background  The relationship between education and Alzheimer disease (AD) or dementia has been widely examined and the evidence obtained is mixed. Several hypotheses have been proposed to explain the observed association between them.

Objective  To further understand the relationship between education and incidence of clinically diagnosed AD or dementia.

Subjects and Methods  A community-based, dementia-free cohort of 1296 aged 75 years and older was followed up to detect incident AD or dementia cases using Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition criteria. The vital status of all subjects who underwent the clinical examination at follow-up (n = 983) was ascertained for 5 years further. Data were analyzed with Cox proportional hazards model after adjustment for main potential confounders.

Results  Over an average (SD) of 2.8 (1.0) years of follow-up, 147 subjects were diagnosed as having dementia (109 subjects as having AD). Among those who were clinically examined at follow-up, 88 died with dementia (68 died with AD) within 5 years. Subjects with a low level of education (<8 vs ≥8 years) had a relative risk of 2.6 (95% confidence interval, 1.5-4.4) for AD and 1.7 (95% confidence interval, 1.1-2.6) for dementia. A low educational level was significantly related to all-cause mortality (relative risk, 1.3; 95% confidence interval, 1.0-1.7; P<.05), but not to the mortality of subjects with AD (relative risk, 1.1; 95% confidence interval, 0.5-2.2) or dementia (relative risk, 0.9; 95% confidence interval, 0.5-1.5).

Conclusions  A low level of education is related to an increased incidence of clinical AD or dementia, but not to the mortality of subjects with AD or dementia. These findings can be accounted for by the "cognitive reserve" hypothesis. Alternatively, the observed association between educational level and incidence of AD or dementia may partly reflect detection bias, by which subjects with a low level of education tend to be clinically diagnosed at an earlier point in time.

THE RELATIONSHIP between education and Alzheimer disease (AD) or dementia has been widely examined over the past decade and the evidence obtained is mixed.1,2 An inverse association between educational level and the risk of AD or dementia has been reported in some cross-sectional38 and case-control studies,9,10 but not in others.1114 Retrospective studies are subject to a number of biases, such as information and selection biases, that may result in an overestimation or underestimation of the association between education and dementia.15,16 Several incidence studies6,1721 and pooled incidence data from Europe22 also demonstrate an inverse association between education and AD or dementia. In contrast, other incidence studies2325 as well as autopsy-verified studies2628 have failed to find any evidence for this reverse relationship. In addition, the effects of potential confounders, such as cognitive functioning prior to dementia, vascular diseases, and socioeconomic status, have been largely neglected by most previous studies addressing this issue.

The interpretation of the association between education and AD or dementia remains controversial. Katzman1 proposed that education could postpone the clinical expression of dementia symptoms by increasing the neocortical synaptic density (the "brain reserve" hypothesis). Stern et al17,29 suggested that educational and occupational attainment provided a reserve against dementia, in that persons with higher educational and occupational attainment could cope with advanced pathologic changes of the disease more effectively by maintaining function longer (the "cognitive reserve" hypothesis). Others27 have argued that persons with greater educational attainment and associated higher socioeconomic status may be exposed to fewer toxins and enjoy a generally healthier lifestyle that may spare the brain from lesions contributing to dementing disorders (the "brain battering" hypothesis). In addition, we have suggested that the observed inverse association may reflect an earlier detection of demented subjects with a low level of education irrespective of the underlying pathologic progress.30 The current study aimed to further understand the relationship between education and clinically diagnosed AD or dementia by integrating incidence with mortality data from the Kungsholmen Project.

STUDY POPULATION

The Kungsholmen Project is a community-based longitudinal study on aging and dementia. The baseline data collection, inception of dementia-free cohort, and follow-up examination have been described in detail elsewhere.31,32 Briefly, the initial population included all registered inhabitants who were living in the Kungsholmen district of Stockholm, Sweden, and were aged 75 years and older in October 1987. Of all eligible subjects (N = 2368), 1810 (76.4%) agreed to participate in the baseline survey (1987-1989). By means of a 2-phase design, 1473 baseline participants were diagnosed as being dementia-free. Of these, 172 persons refused the follow-up examination (1991-1993) or had moved out of Stockholm before the examination and educational information was missing for 5 subjects. Thus, the study population used in the incidence analyses consisted of 1296 baseline dementia-free subjects. Of them, 313 subjects died before undergoing the follow-up examination; medical records and death certificate were available for all of these persons. The remaining subjects (n = 983) underwent a comprehensive medical examination. The vital status of these 983 subjects was ascertained for 5 years further through official registers.

BASELINE DATA COLLECTION

Data on demographic variables (age, sex, and educational level) and global cognitive functioning (assessed using the Mini-Mental State Examination) were collected at the baseline interview according to standardized protocols.31,32 Education was measured by the maximum years of formal schooling. Subjects were divided into 3 categories according to their highest educational level, including elementary school (<8 years of schooling and/or vocational training), high school (8-10 years of schooling), or university (≥11 years of schooling).

Socioeconomic status was assessed based on the lifetime longest occupation that the subject had held. It was divided into 5 categories (self-employed, intermediate nonmanual, assistant nonmanual, skilled manual, unskilled or semiskilled manual work) according to the occupation-based Swedish Socioeconomic Classification System devised by Statistics Sweden in 1982. Data on socioeconomic status were available for 910 subjects.

Data on vascular disorders and other diseases at baseline were derived from the computerized Stockholm Inpatient Registry System, which encompassed all hospitals in the Stockholm area since 1969. All diseases were diagnosed based on the International Classification of Diseases, Eighth Revision (ICD-8), including heart disease (ICD-8 codes 410-414, 427, and 428), cerebrovascular disease (ICD-8 codes 430-438), diabetes mellitus (ICD-8 code 250), hip fracture (ICD-8 code 820), and malignancy (ICD-8 codes 140-208 and 230-239). Arterial blood pressure was measured with a standardized random-zero sphygmomanometer at the baseline interview.

DIAGNOSIS OF DEMENTIA

The Diagnostic and Statistical Manual of Mental Disorders, Third Edition-Revised (DSM-III-R)33 criteria were used to define dementia using a 3-step diagnostic procedure as described elsewhere.32 The diagnosis of dementia was made when a subject completely fulfilled the DSM-III-R criteria, which in this study was labeled clinically diagnosed dementia. The diagnosis of AD requires gradual onset, progressive deterioration, and lack of any other specific causes of dementia. For the deceased subjects, the diagnosis of AD or dementia was made by reviewing medical records, discharge diagnoses, and death certificates. The Clinical Dementia Rating (CDR) score was used to define AD or dementia severity with 3 gradient categories of mild, moderate, and severe.34

STATISTICAL ANALYSES

The incidence and mortality rates were calculated as the number of events (AD, dementia, or death) divided by the corresponding follow-up time (person-years at risk). When calculating the incidence, the follow-up time was estimated from the date of the baseline interview to the date of follow-up examination or death for subjects who did not develop dementia. For those who developed AD or dementia, half of this time was assumed due to the insidious nature of dementia onset.32 We considered the different types of dementia as competing causes of dementia, which means that a subject who developed any type of dementia was no longer at risk of developing other types of dementia. With regard to mortality rates, the follow-up time was defined as the interval between the date of the follow-up examination and the date of death or 5 years.

Cox proportional hazards models were used to estimate the relative risk (RR) and 95% confidence interval (CI) of developing AD or dementia, dying from all causes, or dying with AD or dementia. We assessed interaction effect by including the independent variables and their cross-product term in the same model. Age (in years) at baseline and sex were considered as covariates in all analyses. High blood pressure (systolic pressure ≥160 mm Hg or diastolic pressure ≥95 mm Hg), heart disease, cerebrovascular disease, and diabetes mellitus were combined into one variable called "vascular disease" (yes vs no), which was also used as a covariate in the analysis of education in relation to incidence of clinical AD or dementia. Further, we combined vascular disease, malignancy, and hip fracture into one variable called "comorbidity" (yes vs no), which was used as a covariate in the mortality analysis. All types of dementia combined and AD were used as separate outcomes in all regression analyses.

Table 1 gives the baseline characteristics of the study population by follow-up status. Participants were more frequently affected by vascular disease or other disorders than were dropouts, but the 2 groups were comparable for age, sex, educational level, and baseline Mini-Mental State Examination score.

Table Graphic Jump LocationTable 1. Characteristics of the Dementia-Free Cohort at Baseline by Follow-up Status*
EDUCATION IN RELATION TO INCIDENCE OF AD AND DEMENTIA

Over an average (SD) of 2.8 (1.0) years of follow-up, 147 subjects developed clinical dementia (109 of them were diagnosed as having AD). Table 2 gives the incidence rates of AD and dementia across different educational levels. The dementia incidence for persons with a high school and university education did not differ reliably. Thus, we merged these 2 groups as a reference category (≥8 years of schooling) in the remaining analyses. The association between a low level of education (<8 years) and an increased incidence of AD or dementia was present independently of age, sex, baseline cognitive performance, vascular disease, and socioeconomic status (Table 3).

Table Graphic Jump LocationTable 2. Incidence Rate (IR) (per 1000 Person-Years), Relative Risk (RR), and 95% Confidence Interval (CI) of Alzheimer Disease or Dementia by Educational Levels in 1296 Subjects
Table Graphic Jump LocationTable 3. Relative Risk (RR) and 95% Confidence Interval (CI) of Alzheimer Disease or Dementia Associated With a Low Level of Education (<8 vs ≥8 Years) in 1296 Subjects

The adjusted RRs (95% CIs) of AD and dementia related to a low educational level (<8 vs ≥8 years) were 2.7 (1.5-4.8) and1.9 (1.2-3.1), respectively, in women, and 2.5 (0.6-10.9) and 1.0 (0.4-2.6), respectively, in men. There was a significant interaction between educational level and sex for the incidence of dementia (adjusted RR for the interaction term, 2.8; 95% CI, 1.1-7.6), but not statistically significant for the incidence of AD (adjusted RR for the interaction term, 1.9; 95% CI, 0.4-8.2). The adjusted RRs (95% CIs) of AD and dementia were 3.0 (1.4-6.3) and 2.0 (1.2-3.4), respectively, in the age group of 75- to 84-year-olds, and 1.5 (0.7-3.4) and 1.0 (0.5-2.0), respectively, in the 85-year-olds and older. No statistically significant interaction between education and age on the incidence of dementia or AD was found.

EDUCATION, AD, AND DEMENTIA IN RELATION TO ALL-CAUSE MORTALITY

Among the 983 subjects who were clinically examined at follow-up, 410 subjects died during an average (SD) of 4.0 (1.5) years of observation, resulting in an overall mortality of 104.3 per 1000 person-years. Low level of education, AD, and dementia were significantly related to all-cause mortality. Moreover, significant interactions of education with AD and dementia (nearly at the borderline) on all-cause mortality were found (Table 4). These interactions suggested that subjects with AD or dementia with a low educational level had a decreased risk of death compared with those with a high educational level.

Table Graphic Jump LocationTable 4. Low Educational Level, Alzheimer Disease, and Dementia in Relation to All-Cause Mortality in the 983 Subjects General Population
EDUCATION IN RELATION TO MORTALITY OF SUBJECTS WITH AD OR DEMENTIA

Of the 983 subjects who underwent the follow-up examination, 126 were diagnosed as having dementia (101 as having AD). There was no statistically significant difference in the distribution of CDR scores between subjects with more education and those with less education. Eighty-eight patients with dementia (68 with AD) died within 5 years. The crude mortality of subjects with AD or dementia among persons with less education was about twice as high as that of those with more education in the general population. The relation of less education to the increased mortality of subjects with AD or dementia, however, disappeared after controlling for potential confounding factors, especially dementia severity (Table 5).

Table Graphic Jump LocationTable 5. Mortality (per 1000 Person-years), Relative Risk (RR), and 95% Confidence Interval (CI) of Alzheimer Disease or Dementia Across Educational Levels in 983 Subjects

In line with several previous follow-up studies,1722 we found that a low level of education was associated with an increased risk for developing clinical AD or dementia, even when several potential confounding factors are controlled for. Furthermore, the increased risk of clinical AD or dementia was mainly confined to persons with less than 8 years of education. The association between a low level of education and an increased risk of AD or dementia was more evident in women than in men and in the younger-old age group (ie, 75-84 years) than in the oldest-old age group (85+ years). These results may partly account for the finding of no association between educational level and the risk of AD or dementia in some previous studies. In the Framingham Study,24 for example, the study population included only a small proportion (8.0%) of subjects with an elementary school education and few of them were younger-old women.

The main findings from the mortality data can be summarized into 2 main points: (1) A low educational level, AD, and dementia are important risk factors for death even in the very old, which is in agreement with prior findings.3537 The finding of an interaction between educational level and AD or dementia on all-cause mortality suggests that persons with both a low level of education and AD or dementia are at a decreased risk of death compared with those with both a high educational level and AD or dementia, which is in accord with our previous report that patients with AD who were highly educated had poorer survival than those less educated patients.30 (2) The association between a low level of education and increased mortality of subjects with clinical AD or dementia is influenced by confounders, most prominently dementia severity. These results could be interpreted in view of other findings given that the neuropathologic progression in patients with dementia may eventually lead to a mortality-causing condition.38 First, clinical observations indicate that dementia progression is more rapid in those with a higher education level or with greater premorbid reading activity, following clinical diagnosis.38,39 Second, pathophysiological and imaging evidence indicates that AD-related pathologic changes in the brain are more advanced among subjects with dementia who have a high level of educational attainment than in those with a low level of education, given similar clinical dementia severity.29,40 Third, autopsy-verified studies2628 have documented that education does not affect the pathologic course of AD. Collectively, these observations suggest that education may influence the clinical expression or the detection of AD or dementia, rather than affect the underlying pathologic process of the disease.

Our results are consistent with the cognitive reserve hypothesis.17,29 Alternatively, it is possible that the finding of an association between a low educational level and increased risk of AD or dementia could be partly due to a bias in detecting clinical AD or dementia. Specifically, subjects with dementia who have a low educational level may be clinically diagnosed at an earlier pathologic stage of the disease compared with those who have a high educational level when current clinical diagnostic criteria and procedures are used. This detection bias may occur in the whole process of clinical evaluation of AD or dementia, and particularly in persons with an educational level of less than elementary school.

Some potential limitations of this study deserve mention. First, we could not directly examine the association between education and the mortality of clinical AD or dementia, as we could not determine whether the deceased subjects who had dementia died of AD, dementia, or some other causes. Rather, we addressed the relation between education and the mortality for subjects with clinical AD or dementia in the general population. However, we attempted to control for the effects of other major death-related disorders by use of a comorbidity variable, which included the most frequent underlying causes of death in persons with dementia.41 Therefore, it is conceivable that our results largely reflect the relation between education and the mortality of AD or dementia. Second, AD or dementia cases among deceased subjects might have been underdiagnosed. This may not bias our results because additional analysis (data not shown) in the subpopulation that undertook the clinical examination at follow-up yielded very similar results as those found in the entire population. Finally, the newly developed cases of dementia over the 5 years after the follow-up examination were not considered in our mortality data because the relevant information was unavailable. If anything, this might lead to an underestimation of the effect of dementia on death. Thus, it is unlikely that these limitations jeopardize our main conclusions.

This study suggests that a low level of education is associated with an increased risk of developing clinical AD or dementia, particularly in women and in younger-old age. In addition, a low level of education was related to increased mortality of all causes, but not to mortality of subjects with AD or dementia in the general population. These results imply that education may affect the clinical expression rather than the pathologic course of AD or dementia. These findings may be accounted for by the cognitive reserve hypothesis, but could also reflect the fact that subjects with dementia who were less educated may be clinically diagnosed at an earlier pathologic stage of the disease (detection bias). This possible interpretation needs to be verified by studies integrating the clinical evaluation of AD or dementia with neuropathologic data.

Accepted for publication August 21, 2001.

This research was supported by grants from the Swedish Medical Research Council, the Swedish Council for Social Research, the Swedish Council for Work Life Research, the Swedish Municipal Pension Institute, the Jhsamling-stiftelsen för Alzheimer och demens forskning Foundation, and the Gun and Bertil Stohne Foundation, Stockholm.

We also thank all of our colleagues in the Kungsholmen Project for their cooperation in data collection and management.

Karolinska Institutet and the Stockholm Gerontology Research Center, Stockholm, Sweden: Bengt Winblad, MD, PhD (leader); Laura Fratiglioni, MD, PhD; Lars Bäckman, MD, PhD; Yvonne Forsell, PhD; Åke Wahlin, PhD; Johan Fastbom, MD; Matti Viitanen, MD; Eva von Strauss, PhD; Margareta Grafström, PhD; Anders Wimo, MD. Uppsala University, Uppsala, Sweden: Lars Bäckman, MD, PhD.

Corresponding author and reprints: Chengxuan Qiu, MD, PhD, Stockholm Gerontology Research Center, Box 6401 (Olivecronas väg 4), S-113 82 Stockholm, Sweden (e-mail: chengxuan.qiu@neurotec.ki.se).

Katzman  R Education and the prevalence of dementia and Alzheimer's disease [review]. Neurology.1993;43:13-20.
Gilleard  CJ Education and Alzheimer's disease: a review of recent international epidemiological studies. Aging Mental Health.1997;1:33-46.
Hill  LRKlauber  MRSalmon  DP  et al Functional status, education, and the diagnosis of dementia in the Shanghai survey. Neurology.1993;43:138-145.
Ott  ABreteler  MMBvan Harskamp  F  et al Prevalence of Alzheimer's disease and vascular dementia: association with education: the Rotterdam study. BMJ.1995;310:970-973.
Prencipe  MCasini  ARFerretti  CLattanzio  MTFiorelli  MCulasso  F Prevalence of dementia in an elderly rural population: effects of age, sex, and education. J Neurol Neurosurg Psychiatry.1996;60:628-633.
Schmand  BSmit  JLindeboom  J  et al Low education is a genuine risk factor for accelerated memory decline and dementia. J Clin Epidemiol.1997;50:1025-1033.
De Ronchi  DFratiglioni  LRucci  PPaternicó  AGraziani  SDalmonte  E The effect of education on dementia occurrence in an Italian population with middle to high socioeconomic status. Neurology.1998;50:1231-1238.
Yamada  MSasaki  HMimori  Y  et al Prevalence and risks of dementia in the Japanese population: RERF's Adult Health Study Hiroshima subjects. J Am Geriatr Soc.1999;47:189-195.
The Canadian Study of Health and Aging The Canadian Study of Health and Aging: risk factors for Alzheimer's disease in Canada. Neurology.1994;44:2073-2080.
Moceri  VMKukull  WAEmanuel  Ivan Belle  GLarson  EB Early-life risk factors and the development of Alzheimer's disease. Neurology.2000;54:415-420.
Beard  CMKokmen  EOfford  KPKurland  LT Lack of association between Alzheimer's disease and education, occupation, marital status, or living arrangement. Neurology.1992;42:2063-2068.
Prince  MCullen  MMann  A Risk factors for Alzheimer's disease and dementia: a case-control study based on the MRC elderly hypertension trial. Neurology.1994;44:97-104.
Bonaiuto  SRocca  WALippi  A  et al Education and occupation as risk factors for dementia: a population-based case-control study. Neuroepidemiology.1995;14:101-109.
Chandra  VGanguli  MPandav  RJohnston  JBelle  SDeKosky  ST Prevalence of Alzheimer's disease and other dementias in rural India: the Indo-US Study. Neurology.1998;51:1000-1008.
Geerlings  MISchmand  BJonker  CLindeboom  JBouter  LM Education and incident Alzheimer's disease: a biased association due to selective attrition and use of a two-step diagnostic procedure? Int J Epidemiol.1999;28:492-497.
Ott  Avan Rossum  CTMvan Harskamp  Fvan de Mheen  HHofman  ABreteler  MMB Education and the incidence of dementia in a large population-based study: the Rotterdam Study. Neurology.1999;52:663-666.
Stern  YGurland  BTatemichi  TKTang  MXWilder  DMayeux  R Influence of education and occupation on the incidence of Alzheimer's disease. JAMA.1994;271:1004-1010.
Callahan  CMHall  KSHui  SLMusick  BSUnverzagt  FWHendrie  HC Relationship of age, education, and occupation with dementia among a community-based sample of African Americans. Arch Neurol.1996;53:134-140.
Evans  DAHebert  LEBeckett  LA  et al Education and other measures of socioeconomic status and risk of incident Alzheimer disease in a defined population of older persons. Arch Neurol.1997;54:1399-1405.
Letenneur  LGilleron  VCommenges  DHelmer  COrgogozo  JMDartigues  JF Are sex and educational level independent predictors of dementia and Alzheimer's disease? incidence data from the PAQUID project. J Neurol Neurosurg Psychiatry.1999;66:177-183.
Ganguli  MDodge  HHChen  PBelle  SDeKosky  ST Ten-year incidence of dementia in a rural elderly US community population: the MoVIES Project. Neurology.2000;54:1109-1116.
Letenneur  LLauner  LJAndersen  K  et alfor the EURODEM Incidence Research Group Education and the risk for Alzheimer's disease: sex makes a difference: EURODEM pooled analyses. Am J Epidemiol.2000;151:1064-1071.
Paykel  ESBrayne  CHuppert  FA  et al Incidence of dementia in a population older than 75 years in the United Kingdom. Arch Gen Psychiatry.1994;51:325-332.
Cobb  JLWolf  PAAu  RWhite  RD'Agostino  RB The effect of education on the incidence of dementia and Alzheimer's disease in the Framingham Study. Neurology.1995;45:1707-1712.
Hall  KSGao  SUnverzagt  FWHendrie  HC Low education and childhood rural residence: risk for Alzheimer's disease in African Americans. Neurology.2000;54:95-99.
Bowler  JVMunoz  DGMerskey  HHachinski  V Factors affecting the age of onset and rate of progression of Alzheimer's disease. J Neurol Neurosurg Psychiatry.1998;65:184-190.
Del Ser  THachinski  VMerskey  HMunoz  DG An autopsy-verified study of the effect of education on degenerative dementia. Brain.1999;122:2309-2319.
Munoz  DGGanapathy  GREliasziw  MHachinski  V Educational attainment and socioeconomic status of patients with autopsy-confirmed Alzheimer disease. Arch Neurol.2000;57:85-89.
Stern  YTang  MXDenaro  JMayeux  R Increased risk of mortality in Alzheimer's disease patients with more advanced educational and occupational attainment. Ann Neurol.1995;37:590-595.
Fratiglioni  LViitanen  MAgüero-Torres  HBäckman  LWinblad  B Low education and AD: effects on diagnostics rather than risk [abstract]. Neurobiol Aging.1998;19(suppl 4):214.
Fratiglioni  LViitanen  MBäckman  LSandman  POWinblad  B Occurrence of dementia in advanced age: the study design of the Kungsholmen Project. Neuroepidemiology.1992;11(suppl 1):29-36.
Fratiglioni  LViitanen  Mvon Strauss  ETontodonati  VHerlitz  AWinblad  B Very old women at highest risk of dementia and Alzheimer's disease: incidence data from the Kungsholmen Project, Stockholm. Neurology.1997;48:132-138.
American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition.  Washington, DC: American Psychiatric Association; 1987.
Hughes  CPBerg  LDanziger  WLCoben  LAMartin  RL A new clinical scale for the staging of dementia. Br J Psychiatry.1982;140:566-572.
Katzman  RHill  LRYu  ES  et al The malignancy of dementia: predictors of mortality in clinically diagnosed dementia in a population survey of Shanghai, China. Arch Neurol.1994;51:1220-1225.
Baldereschi  MDi Carlo  AMaggi  S  et alfor the Italian Longitudinal Study on Aging Working Group Dementia is a major predictor of death among the Italian elderly. Neurology.1999;52:709-713.
Wolfson  CWolfson  DBAsgharian  M  et al A reevaluation of the duration of survival after the onset of dementia. N Engl J Med.2001;344:1111-1116.
Stern  YAlbert  STang  MXTsai  WY Rate of memory decline in AD is related to education and occupation: cognitive reserve? Neurology.1999;53:1942-1947.
Wilson  RSBennett  DAGilley  DWBeckett  LABarnes  LLEvans  DA Premorbid reading activity and patterns of cognitive decline in Alzheimer disease. Arch Neurol.2000;57:1718-1723.
Stern  YAlexander  GEProhovnik  IMayeux  R Inverse relationship between education and parietotemporal perfusion deficit in Alzheimer's disease. Ann Neurol.1992;32:371-375.
Lanska  DJ Dementia mortality in the United States: results of the 1986 National Mortality Followback Survey. Neurology.1998;50:362-367.

Figures

Tables

Table Graphic Jump LocationTable 1. Characteristics of the Dementia-Free Cohort at Baseline by Follow-up Status*
Table Graphic Jump LocationTable 2. Incidence Rate (IR) (per 1000 Person-Years), Relative Risk (RR), and 95% Confidence Interval (CI) of Alzheimer Disease or Dementia by Educational Levels in 1296 Subjects
Table Graphic Jump LocationTable 3. Relative Risk (RR) and 95% Confidence Interval (CI) of Alzheimer Disease or Dementia Associated With a Low Level of Education (<8 vs ≥8 Years) in 1296 Subjects
Table Graphic Jump LocationTable 4. Low Educational Level, Alzheimer Disease, and Dementia in Relation to All-Cause Mortality in the 983 Subjects General Population
Table Graphic Jump LocationTable 5. Mortality (per 1000 Person-years), Relative Risk (RR), and 95% Confidence Interval (CI) of Alzheimer Disease or Dementia Across Educational Levels in 983 Subjects

References

Katzman  R Education and the prevalence of dementia and Alzheimer's disease [review]. Neurology.1993;43:13-20.
Gilleard  CJ Education and Alzheimer's disease: a review of recent international epidemiological studies. Aging Mental Health.1997;1:33-46.
Hill  LRKlauber  MRSalmon  DP  et al Functional status, education, and the diagnosis of dementia in the Shanghai survey. Neurology.1993;43:138-145.
Ott  ABreteler  MMBvan Harskamp  F  et al Prevalence of Alzheimer's disease and vascular dementia: association with education: the Rotterdam study. BMJ.1995;310:970-973.
Prencipe  MCasini  ARFerretti  CLattanzio  MTFiorelli  MCulasso  F Prevalence of dementia in an elderly rural population: effects of age, sex, and education. J Neurol Neurosurg Psychiatry.1996;60:628-633.
Schmand  BSmit  JLindeboom  J  et al Low education is a genuine risk factor for accelerated memory decline and dementia. J Clin Epidemiol.1997;50:1025-1033.
De Ronchi  DFratiglioni  LRucci  PPaternicó  AGraziani  SDalmonte  E The effect of education on dementia occurrence in an Italian population with middle to high socioeconomic status. Neurology.1998;50:1231-1238.
Yamada  MSasaki  HMimori  Y  et al Prevalence and risks of dementia in the Japanese population: RERF's Adult Health Study Hiroshima subjects. J Am Geriatr Soc.1999;47:189-195.
The Canadian Study of Health and Aging The Canadian Study of Health and Aging: risk factors for Alzheimer's disease in Canada. Neurology.1994;44:2073-2080.
Moceri  VMKukull  WAEmanuel  Ivan Belle  GLarson  EB Early-life risk factors and the development of Alzheimer's disease. Neurology.2000;54:415-420.
Beard  CMKokmen  EOfford  KPKurland  LT Lack of association between Alzheimer's disease and education, occupation, marital status, or living arrangement. Neurology.1992;42:2063-2068.
Prince  MCullen  MMann  A Risk factors for Alzheimer's disease and dementia: a case-control study based on the MRC elderly hypertension trial. Neurology.1994;44:97-104.
Bonaiuto  SRocca  WALippi  A  et al Education and occupation as risk factors for dementia: a population-based case-control study. Neuroepidemiology.1995;14:101-109.
Chandra  VGanguli  MPandav  RJohnston  JBelle  SDeKosky  ST Prevalence of Alzheimer's disease and other dementias in rural India: the Indo-US Study. Neurology.1998;51:1000-1008.
Geerlings  MISchmand  BJonker  CLindeboom  JBouter  LM Education and incident Alzheimer's disease: a biased association due to selective attrition and use of a two-step diagnostic procedure? Int J Epidemiol.1999;28:492-497.
Ott  Avan Rossum  CTMvan Harskamp  Fvan de Mheen  HHofman  ABreteler  MMB Education and the incidence of dementia in a large population-based study: the Rotterdam Study. Neurology.1999;52:663-666.
Stern  YGurland  BTatemichi  TKTang  MXWilder  DMayeux  R Influence of education and occupation on the incidence of Alzheimer's disease. JAMA.1994;271:1004-1010.
Callahan  CMHall  KSHui  SLMusick  BSUnverzagt  FWHendrie  HC Relationship of age, education, and occupation with dementia among a community-based sample of African Americans. Arch Neurol.1996;53:134-140.
Evans  DAHebert  LEBeckett  LA  et al Education and other measures of socioeconomic status and risk of incident Alzheimer disease in a defined population of older persons. Arch Neurol.1997;54:1399-1405.
Letenneur  LGilleron  VCommenges  DHelmer  COrgogozo  JMDartigues  JF Are sex and educational level independent predictors of dementia and Alzheimer's disease? incidence data from the PAQUID project. J Neurol Neurosurg Psychiatry.1999;66:177-183.
Ganguli  MDodge  HHChen  PBelle  SDeKosky  ST Ten-year incidence of dementia in a rural elderly US community population: the MoVIES Project. Neurology.2000;54:1109-1116.
Letenneur  LLauner  LJAndersen  K  et alfor the EURODEM Incidence Research Group Education and the risk for Alzheimer's disease: sex makes a difference: EURODEM pooled analyses. Am J Epidemiol.2000;151:1064-1071.
Paykel  ESBrayne  CHuppert  FA  et al Incidence of dementia in a population older than 75 years in the United Kingdom. Arch Gen Psychiatry.1994;51:325-332.
Cobb  JLWolf  PAAu  RWhite  RD'Agostino  RB The effect of education on the incidence of dementia and Alzheimer's disease in the Framingham Study. Neurology.1995;45:1707-1712.
Hall  KSGao  SUnverzagt  FWHendrie  HC Low education and childhood rural residence: risk for Alzheimer's disease in African Americans. Neurology.2000;54:95-99.
Bowler  JVMunoz  DGMerskey  HHachinski  V Factors affecting the age of onset and rate of progression of Alzheimer's disease. J Neurol Neurosurg Psychiatry.1998;65:184-190.
Del Ser  THachinski  VMerskey  HMunoz  DG An autopsy-verified study of the effect of education on degenerative dementia. Brain.1999;122:2309-2319.
Munoz  DGGanapathy  GREliasziw  MHachinski  V Educational attainment and socioeconomic status of patients with autopsy-confirmed Alzheimer disease. Arch Neurol.2000;57:85-89.
Stern  YTang  MXDenaro  JMayeux  R Increased risk of mortality in Alzheimer's disease patients with more advanced educational and occupational attainment. Ann Neurol.1995;37:590-595.
Fratiglioni  LViitanen  MAgüero-Torres  HBäckman  LWinblad  B Low education and AD: effects on diagnostics rather than risk [abstract]. Neurobiol Aging.1998;19(suppl 4):214.
Fratiglioni  LViitanen  MBäckman  LSandman  POWinblad  B Occurrence of dementia in advanced age: the study design of the Kungsholmen Project. Neuroepidemiology.1992;11(suppl 1):29-36.
Fratiglioni  LViitanen  Mvon Strauss  ETontodonati  VHerlitz  AWinblad  B Very old women at highest risk of dementia and Alzheimer's disease: incidence data from the Kungsholmen Project, Stockholm. Neurology.1997;48:132-138.
American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition.  Washington, DC: American Psychiatric Association; 1987.
Hughes  CPBerg  LDanziger  WLCoben  LAMartin  RL A new clinical scale for the staging of dementia. Br J Psychiatry.1982;140:566-572.
Katzman  RHill  LRYu  ES  et al The malignancy of dementia: predictors of mortality in clinically diagnosed dementia in a population survey of Shanghai, China. Arch Neurol.1994;51:1220-1225.
Baldereschi  MDi Carlo  AMaggi  S  et alfor the Italian Longitudinal Study on Aging Working Group Dementia is a major predictor of death among the Italian elderly. Neurology.1999;52:709-713.
Wolfson  CWolfson  DBAsgharian  M  et al A reevaluation of the duration of survival after the onset of dementia. N Engl J Med.2001;344:1111-1116.
Stern  YAlbert  STang  MXTsai  WY Rate of memory decline in AD is related to education and occupation: cognitive reserve? Neurology.1999;53:1942-1947.
Wilson  RSBennett  DAGilley  DWBeckett  LABarnes  LLEvans  DA Premorbid reading activity and patterns of cognitive decline in Alzheimer disease. Arch Neurol.2000;57:1718-1723.
Stern  YAlexander  GEProhovnik  IMayeux  R Inverse relationship between education and parietotemporal perfusion deficit in Alzheimer's disease. Ann Neurol.1992;32:371-375.
Lanska  DJ Dementia mortality in the United States: results of the 1986 National Mortality Followback Survey. Neurology.1998;50:362-367.

Correspondence

CME
Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
Submit a Comment

Multimedia

Some tools below are only available to our subscribers or users with an online account.

Web of Science® Times Cited: 106

Related Content

Customize your page view by dragging & repositioning the boxes below.

Articles Related By Topic
Related Collections
PubMed Articles
JAMAevidence.com

Users' Guides to the Medical Literature
Clinical Resolution

Users' Guides to the Medical Literature
Clinical Scenario