Incident Cases Of Mild Cognitive Impairment Research Articles

6 Depressive Symptoms are Associated With Decline Over Time in Verbal Fluency Performance in Female but not Male Community-Dwelling Older Adults

Objective:Late-life depression is prevalent among older adults and the presence of depressive symptoms has been shown to be associated cross-sectionally with worse verbal fluency performance. There is limited and mixed evidence as to whether depressive symptoms impact change in verbal fluency performance over time, and whether gender impacts this relationship.Participants and Methods:Participants were community-dwelling older adults who were dementia-free at baseline (N = 522; M age = 75.96, SD + 6.46 years). Baseline depressive symptoms were measured using the Geriatric Depression Scale. Category fluency and letter fluency performance, using the Controlled Oral Word Association Test (COWAT), were examined annually. Linear mixed effects models stratified by gender examined whether associations between baseline depressive symptoms and changes in fluency performance over five years were different in female (n = 289) as compared to male (n = 233) participants. Sensitivity analyses excluding participants with prevalent or incident mild cognitive impairment (MCI) (n = 141), excluding participants with incident dementia (n = 28), and excluding participants with prevalent or incident MCI or incident dementia (n = 169) were run. All analyses were adjusted for age, years of education, estimated premorbid functioning, and health comorbidities.Results:Depression was minimal across participants (m = 4.72, SD + 3.96). A subset of participants (n = 44) reported “possible depression,” namely levels suggestive of subclinical depression, according to clinical cutoffs. The “possible depression” group included 31 females (10.73% of females) and 13 males (5.58% of males), and the “no depression” group included 258 females (89.27% of females) and 220 males (94.42% of males). Baseline levels of depressive symptoms suggestive of subclinical depression were associated with worse decline in category fluency performance during longitudinal follow-up in females (estimate = -0.16, p = .002) but not males (estimate = -0.03, p = .658). Results remained the same when excluding prevalent and incident MCI cases (estimate = -0.19, p = .005), excluding incident dementia cases (estimate = -0.12, p = .017), and excluding prevalent and incident MCI and incident dementia cases (estimate = -0.20, p = .004). Letter fluency performance did not decline over time and was not influenced by levels of depressive symptoms in females (estimate = -0.03, p = .502) or males (estimate = 0.05, p = .452).Conclusions:Baseline presence of depressive symptoms suggestive of subclinical depression was associated with worse decline in category fluency performance during longitudinal follow-up in female but not male participants. Letter fluency performance did not decline and was not impacted by levels of depressive symptoms. Results remained significant when accounting for covariates and potential confounders. The present study elucidated the combined influence of gender and depressive symptoms on change in fluency performance in older adults and can aid in identifying individuals who may be at a greater risk of cognitive decline.

Circulating folate concentrations and the risk of mild cognitive impairment: A prospective study on the older Chinese population without folic acid fortification.

The longitudinal association between serum folate concentrations and the risk of cognitive impairment remains unclear in populations with low folate levels. We examined the association between serum folate concentrations and mild cognitive impairment (MCI) in older adults in China, where mandatory fortification of foods with folic acid has not been implemented. We further explored if homocysteine (Hcy) and leukocyte telomere length (LTL) mediate the association between serum folate and MCI. We performed a longitudinal analysis of 3974 participants aged ≥60 years from the Tianjin Elderly Nutrition and Cognition (TENC) cohort study. The associations between serum folate level and the risk of cognitive impairment overall and stratified by apolipoprotein E (APOE) ε4 genotypes were evaluated using multivariable Cox proportional hazards models. The mediating effects of Hcy and LTL on the folate-MCI association were explored via a path analysis approach. Within a 3-year follow-up, we documented 560 incident MCI cases. After multivariable adjustment, higher serum folate concentrations were associated with lower incidence of MCI, with hazard ratios (95% confidence interval) across quartiles of folate (from lowest to highest concentrations) of 1.00 (reference), 0.66 (0.52, 0.83), 0.57 (0.45, 0.73), 0.66 (0.52, 0.84), respectively (p for trend <0.001). In mediation analyses, the status of serum folate deficiency and MCI were correlated via two intermediary pathways, Hcy and Hcy-telomere (p < 0.05). Lower folate concentrations, independently of APOE genotype, were associated with increased risk of MCI among elderly Chinese people, a population with relatively low folate intake. Our data were compatible with the mediation hypothesis that the association between folate status and MCI was mediated by Hcy and LTL.

Predictors of Incident Mild Cognitive Impairment and Its Course in a Diverse Community-Based Population.

Background and ObjectivesTo investigate sociodemographic and medical predictors of incident mild cognitive impairment (MCI) and subsequent course of MCI at follow-up, including sustained MCI diagnosis, classification as cognitively normal, and progression to dementia.MethodsWithin a community-based cohort, diagnoses of MCI were made with a published algorithm. Diagnosis of dementia was based on clinical consensus. Cox regressions estimated hazard ratios of incident MCI associated with several predictors. Modified Poisson regressions estimated relative risks associated with predictors of diagnostic status at follow-up after incidence.ResultsAmong 2,903 cognitively normal participants at baseline, 752 developed MCI over an average of 6.3 (SD 4.5) years (incidence rate 56 per 1,000 person-years). Presence of APOE ε4 and higher medical burden increased risk of incident MCI, while more years of education, more leisure activities, and higher income decreased this risk. Of the incident MCI cases, after an average of 2.4 years of follow-up, 12.9% progressed to dementia, 9.6% declined in functioning and did not meet the algorithmic criteria for MCI but did not meet the clinical criteria for dementia, 29.6% continued to meet MCI criteria, and 47.9% no longer met MCI criteria. Multidomain MCI, presence of APOE ε4, depressive symptoms, and antidepressant use increased the risk of progression to dementia.DiscussionThis community-based study showed that almost half of the individuals with incident MCI diagnoses were classified as cognitively normal at follow-up. Predictors of incident MCI demonstrably differed from those of subsequent MCI course; these findings can refine expectations for cognitive and functional course of those presenting with MCI.

Abstract 10561: Attending Cardiac Rehabilitation Reduces Incidence of Dementia but Not Mild Cognitive Impairment in Patients with Coronary Artery Disease

Introduction: Coronary artery disease (CAD) has been associated with cognitive decline. Cardiac rehabilitation (CR) is a class 1A recommendation for patients with CAD as it reduces future cardiac events and mortality. However, the impact of CR on incidence of mild cognitive impairment (MCI) and dementia has not been extensively studied. We investigated the association of CAD on incidence of MCI and dementia; and whether CR attendance reduces incidence of MCI and dementia in patients with CAD Methods: The Mayo Clinic Study of Aging (MCSA), a prospective, population-based cohort was probed for this study. At baseline and every 15-months thereafter, subjects were evaluated for MCI and dementia using a standardized protocol. Data on CR participation were collected via record linkage to the Rochester Epidemiology Project. To evaluate association with incident MCI or dementia, cox proportional hazard models were used and adjusted for age, sex, and clinical predictors of cognitive decline. Participants with MCI at baseline were excluded for MCI analysis and adjusted for in dementia analysis. Results: We included 5960 MCSA participants (female: 50%; age: 70±13). Of those, 1934 participants (32%) had CAD and 702 (12%) had MCI at baseline. Mean follow-up was 3.9±3.7yrs, with 760 incident cases of MCI (13%) and 290 cases of dementia (5%). CAD was a significant predictor of MCI and dementia, although after adjustment for other clinical predictors, CAD was only associated with MCI incidence ( Table 1, Figure ). Incidence of dementia was reduced in CAD patients who had a greater attendance at CR when adjusted for other predictors of cognitive decline ( Table 2 ). Attendance at CR did not reduce incidence of MCI ( Table 2 ). Conclusions: CAD was a significant predictor of MCI and dementia. In patients with CAD, a higher attendance of CR was associated with reduced incidence of dementia but not MCI. Specific CR programming and outcome targets may be needed to prevent MCI in patients with CAD.

Depressive symptoms and cognitive impairment: A 10-year follow-up study from the Survey of Health, Ageing and Retirement in Europe.

Depressive symptoms and cognitive impairment often coexisted in the elderly. This study investigates the effect of late-life depressive symptoms on risk of mild cognitive impairment (MCI). A total of 14,231 dementia- and MCI free participants aged 60+ from the Survey of Health, Ageing, and Retirement in Europe were followed-up for 10 years to detect incident MCI. MCI was defined as 1.5 standard deviation (SD) below the mean of the standardized global cognition score. Depressive symptoms were assessed by a 12-item Europe-depression scale (EURO-D). Severity of depressive symptoms was grouped as: no/minimal (score 0-3), moderate (score 4-5), and severe (score 6-12). Significant depressive symptoms (SDSs) were defined as EURO-D score ≥ 4. During an average of 8.2 (SD = 2.4)-year follow-up, 1,352 (9.50%) incident MCI cases were identified. SDSs were related to higher MCI risk (hazard ratio [HR] = 1.26, 95% confidence intervals [CI]: 1.10-1.44) in total population, individuals aged 70+ (HR = 1.35, 95% CI: 1.14-1.61) and women (HR = 1.28, 95% CI: 1.08-1.51) in Cox proportional hazard model adjusting for confounders. In addition, there was a dose-response association between the severity of depressive symptoms and MCI incidence in total population, people aged ≥70 years and women (p-trend <0.001). Significant depressive symptoms were associated with higher incidence of MCI in a dose-response fashion, especially among people aged 70+ years and women. Treating depressive symptoms targeting older population and women may be effective in preventing MCI.

Neuropsychological comparison of incident MCI and prevalent MCI

IntroductionLittle empirical work has been done to examine differences between mild cognitive impairment (MCI) diagnosed in research settings with longitudinal data (incident MCI) and MCI diagnosed in clinical settings (prevalent MCI). Because Alzheimer's disease progresses over a clinicopathological continuum, we examined the cognitive differences between these two different sources of MCI patients. MethodsWe compared 52 consecutively identified patients with prevalent amnestic MCI with 53 incident amnestic MCI participants from the Arizona APOE study. Neuropsychological data from common tests were compared encompassing four cognitive domains and one global indicator. ResultsPrevalent MCI cases performed significantly worse than incident MCI cases on global as well as domain-specific measures. DiscussionBy the time patients seek evaluation for memory loss, they have more severe single domain, amnestic MCI than research subjects with incident MCI. Studies of MCI should distinguish incident and prevalent not just single- and multiple-domain MCI.

Longitudinal study of normal cognition in Parkinson disease.

To report the rates and predictors of progression from normal cognition to either mild cognitive impairment (MCI) or dementia using standardized neuropsychological methods. A prospective cohort of patients diagnosed with Parkinson disease (PD) and baseline normal cognition was assessed for cognitive decline, performance, and function for a minimum of 2 years, and up to 6. A panel of movement disorders experts classified patients as having normal cognition, MCI, or dementia, with 55/68 (80.9%) of eligible patients seen at year 6. Kaplan-Meier curves and Cox proportional hazard models were used to examine cognitive decline and its predictors. We enrolled 141 patients, who averaged 68.8 years of age, 63% men, who had PD on average for 5 years. The cumulative incidence of cognitive impairment was 8.5% at year 1, increasing to 47.4% by year 6. All incident MCI cases had progressed to dementia by year 5. In a multivariate analysis, predictors of future decline were male sex (p = 0.02), higher Unified Parkinson's Disease Rating Scale motor score (p ≤ 0.001), and worse global cognitive score (p < 0.001). Approximately half of patients with PD with normal cognition at baseline develop cognitive impairment within 6 years and all new MCI cases progress to dementia within 5 years. Our results show that the transition from normal cognition to cognitive impairment, including dementia, occurs frequently and quickly. Certain clinical and cognitive variables may be useful in predicting progression to cognitive impairment in PD.

Greater weight change per decade from midlife through late life predicts incident MCI

Unintentional weight loss has been associated with risk of dementia. Few large population-based studies have examined the association of weight change with risk of mild cognitive impairment (MCI). We aim to investigate the association of rate of weight change per decade with risk of MCI. Cognitively normal participants (n=2,061; mean age, 78.8 years; 50.5% male) in the population-based prospective Mayo Clinic Study of Aging were clinically evaluated every 15 months for incident MCI. Weight and height at ages 70 or older were measured at each evaluation. Maximum adult weight and height in midlife (i.e. ages 40 to 65 years; mean, 59.7) were ascertained for each participant using a medical records linkage system. We investigated the association of weight change per decade (from midlife through late life) with risk of MCI using proportional hazards models with age as the time scale. Over a mean (SD) follow-up of 4.4 (2.4) years, 578 participants developed incident MCI. The mean weight change per decade (in kilograms) was -1.8 (6.5) for persons with incident MCI cases vs. -1.2 (6.1) for persons who remained cognitively normal (p = 0.015). Declining weight per decade was associated with an increased risk of MCI (beta (SE), -0.031 [0.007]; p <0.0001) after adjustment for sex and education. There was a sex difference showing a stronger association in men (beta, -0.04 [0.012], p = 0.0002) than in women (beta, -0.022 [0.010]; p = 0.026). Risk of MCI also increased with decline in body mass index per decade (-0.059 [0.019], p = 0.002). The rate of weight change from midlife through late life predicts incident MCI and should be considered in risk stratification models for MCI. The stronger association in men may relate to the earlier onset of MCI in men observed in our previous studies.

Incidence of mild cognitive impairment in the Pittsburgh Cardiovascular Health Study-Cognition Study.

The purpose of this study was to examine the incidence of mild cognitive impairment (MCI) and patterns of progression from incident MCI to dementia in 285 cognitively normal subjects (mean age, 78.9 years) in the Cardiovascular Health Study-Cognition Study from 1998-1999 to 2010-2011. Two hundred (70%) of the participants progressed to MCI; the age-adjusted incidence of MCI was 111.09 (95% confidence interval, 88.13-142.95) per 1,000 person-years. A total of 107 (53.5%) of the incident MCI subjects progressed to dementia. The mean time from MCI to dementia was 2.8 ± 1.8 years. Forty (20%) of the incident MCI cases had an "unstable" course: 19 (9.5%) converted to MCI and later returned to normal; 10 (5%) converted to MCI, to normal, and later back to MCI; 7 (3.5%) converted to MCI, to normal, to MCI, and later to dementia; and 4 (2%) converted to MCI, to normal, and later to dementia. There was an increased mortality rate among the cognitively normal group (110.10 per 1,000 person-years) compared to those with incident MCI who converted to dementia (41.32 per 1,000 person-years). The majority of the subjects aged >80 years developed an MCI syndrome, and half of them progressed to dementia. Once the MCI syndrome was present, the symptoms of dementia appeared within 2 to 3 years. Progression from normal to MCI or from normal to MCI to dementia is not always linear; subjects who developed MCI and later returned to normal can subsequently progress to dementia. Competing mortality and morbidity influence the study of incident MCI and dementia in population cohorts.

Incidence of Mild Cognitive Impairment in the CHS Cognition Study (S24.001)

Objective: To examine the incidence of mild cognitive impairment (MCI) in the Cardiovascular Health Study-Cognition Study. Background Older subjects with MCI have an increased risk of developing dementia. Design/Methods: We examined the incidence of MCI and patterns of progression from incident MCI to dementia in 285 normal subjects (mean age: 78.9) participating in the CHS-CS from 1998-99 to 2010-2011. Results: 200 (70%) of the participants progressed to MCI; the age-adjusted incidence of MCI was 112.09 (95% CI: 88.1 – 142.95) per/1000 persons-years. 110 (55%) of the incident MCI subjects progressed to dementia. The mean time to MCI was 5.9 + 2.7 years and from the MCI to dementia 2.8 + 1.8 years. 40 (20%) of the incident MCI cases had an “unstable” course: 19 (9.5%) converted to MCI and later returned to normal, 10 (5%) converted to MCI to normal and later went back to MCI, 7 (3.5%) converted to MCI to normal to MCI and later to dementia, and 4 (2%) converted to MCI to normal and later to dementia. Conclusions: The majority of the subjects older than age 80 developed an MCI syndrome and half progressed to dementia. Progression from normal to MCI or from normal to MCI to dementia is not always linear; 20% of the subjects had a fluctuating course. Subjects who developed MCI and later returned to normal can progress to dementia during follow-up. Importantly, once the MCI syndrome is present, the symptoms of dementia appear within 2-3 years. This suggests that the window to detect symptomatic pre-dementia cases is narrow in this age group, which has important implications for the development of prevention therapies. Supported by: The research reported in this article was supported by contracts N01-HC-85079 through N01-HC-85086, N01-HC-35129, and N01-HC-15103 from the National Heart, Lung, and Blood Institute, and grants AG15928 and AG20098 from the National Institute on Aging. Disclosure: Dr. Lopez has received personal compensation for activities with Lundbeck and Johnson & Johnson as a consultant. Dr. Becker has nothing to disclose. Dr. Chang has nothing to disclose. Dr. Sweet has nothing to disclose. Dr. DeKosky has received personal compensation in an editorial capacity for Up-to-Date, Inc. Dr. Gach has nothing to disclose. Dr. Carmichael has nothing to disclose. Dr. McDade has nothing to disclose. Dr. Kuller has nothing to disclose.

Serum Thyroid-Stimulating Hormone as a Predictor of Cognitive Impairment in an Elderly Cohort

Background: It is unclear whether in late life serum thyroid-stimulating hormone (TSH) predicts risk of developing cognitive impairment. Objective: This study investigated the prospective relationship of serum TSH with the risk of developing mild cognitive impairment (MCI), Alzheimer’s disease (AD) and vascular dementia (VaD) in an elderly cohort with a 4-year follow-up. Methods: Data are for 660 subjects aged 65 years and older from an Italian population-based cohort who were cognitively normal at an extensive assessment in 1999/2000 and underwent follow-up assessment in 2003/2004. Serum TSH was measured at baseline. Multinomial logistic models adjusted for sociodemographic and cardiovascular risk factors were used to investigate the association of serum TSH (both as a tertile and continuous log-transformed variable) with risk of incident MCI, AD and VaD diagnosed according to international criteria. Results: Over 3.8 ± 0.7 years of follow-up, there were 149 incident MCI cases (77 with impairment of memory and 72 with impairment of nonmemory domains) and 86 incident dementia cases (53 with AD, 28 with VaD). No association between baseline TSH and risk of developing any MCI subtype or AD was found. The highest TSH tertile had a threefold higher increased risk of VaD (OR: 3.25, 95% CI: 1.01–10.77, p = 0.048) compared to the lowest tertile. Risk of VaD increased about 60% for each 1 SD increase in log-transformed TSH (OR: 1.61, 95% CI: 1.06–2.44, p = 0.025). Conclusions: In this elderly cohort, baseline TSH was not related to the risk of developing MCI or AD, but high TSH was associated with an increased risk of VaD. These results suggest further need for research using larger samples to examine the role of TSH as a predictor of VaD and the role of thyroid autoimmunity in vascular cognitive impairment.

Mild Cognitive Impairment: Incidence and Risk Factors: Results of the Leipzig Longitudinal Study of the Aged

To provide information on age- and sex-specific incidence rates of mild cognitive impairment (MCI) and risk factors for incident MCI. Prospective longitudinal cohort. Leipzig Longitudinal Study of the Aged, a population-based German study of the epidemiology of dementia and mild cognitive impairment. At baseline, 1,692 subjects aged 75 and older were included in the sample. Trained psychologists and physicians conducted structured clinical interviews including neuropsychological assessment and questions about sociodemographics, familial history of dementia, activities of daily living, subjective memory impairment, and lifestyle (alcohol consumption, smoking) at participants' homes. Structured third-party interviews were conducted with proxies. Incidence was calculated according to the person-years-at-risk method. Cox proportional hazards models were used to examine the association between risk factors and incident MCI. During an 8-year follow-up period, 26.4% (n=137) of the 519 study participants (population at risk) were identified as incident MCI cases (person-years=1,791.1). The overall incidence rate of MCI was 76.5 (95% confidence interval=64.7-90.4) per 1,000 person-years. Older age, subjective memory impairment, impairment in instrumental activities of daily living, and antecedent lower cognitive performance were found to be significantly associated with the development of future MCI. MCI is highly incident in the elderly population. For the purpose of early detection of dementia, subjective memory impairment should be taken seriously as a possible prestage of MCI.

Differential effects of APOE genotype and vascular risk factors on MCI and dementia

Risk factors for incident mild cognitive impairment (MCI) are less well understood than those for dementia (DEM). The Mayo Clinic Study of Aging is a prospective, longitudinal study of elders aged 70-89 yrs. The present analysis concerns 1969 participants (1640 cognitively normal (CN); 329 with MCI) who were diagnosed by a consensus diagnostic process as non-demented at their initial evaluation. Participants were re-evaluated twice at 15 month intervals. The diagnostic process included a physician examination, a neuropsychological battery, and an informant interview. Standard published diagnostic criteria for CN, MCI and DEM were used. At the initial examination, a medical history including a history of stroke was obtained from the subjects. Vascular risk factors were assessed. APOE genotype was determined. Cox regression analyses were used to determine associations between predictors and incident MCI or DEM. Among initially CN subjects over 30 months (88.1% follow-up rate: mean age 79.5; 50.1% women; 43.3% with < 12 yrs education; 6.7% history of stroke; 24.7% APOE e4 carriers), there were 208 incident MCI cases (134 amnestic and 55 non-amnestic MCI). Age>80 yrs, male sex and <12 yrs of education were risk factors for incident MCI. Controlling for those demographic variables, carriage of APOE e4 allele (hazard ratio (HR) =1.47, 95% CI=1.10-1.97), history of stroke (HR =2.17, 95% CI=1.45-3.23) and diabetes (HR=1.46, 95% CI=1.06-2.01) were associated with incident MCI. Hypertension was not a risk factor for incident MCI. Among initially MCI subjects (85.1% follow-up rate), 71 (25.4%) became demented. Neither age, sex, education, APOE e4 carriage, history of stroke, diabetes nor hypertension were significant predictors of incident dementia in persons with MCI. The transition from CN to MCI, but not from MCI to DEM, was influenced by demographic features, APOE e4 genotype, diabetes and history of stroke. Once cognitive impairment is present, the predictors we studied had no impact on subsequent progression. Stroke history, even of events remote in time, is an important risk factor for cognitive impairment. Persistence of associations of incident MCI with diabetes and APOE genotype in this elderly cohort are remarkable.

Mild Cognitive Impairment: Epidemiology and Dementia Risk in an Elderly Italian Population

To investigate prevalence and incidence of mild cognitive impairment (MCI) and its risk of progression to dementia in an elderly Italian population. Longitudinal. Population-based cohort aged 65 and older resident in an Italian municipality. A total of 1,016 subjects underwent baseline evaluation in 1999/2000. In 2003/04, information about cognitive outcome was collected for 745 participants who were free of dementia at baseline. MCI (classified as with or without impairment of the memory domain), dementia, Alzheimer's dementia (AD), and vascular dementia (VaD) diagnosed according to current international criteria. Overall prevalence of MCI was 7.7% (95% confidence interval (CI)=6.1-9.7 %) and was greater with older age and poor education. During 4 years of follow-up, 155 incident MCI cases were diagnosed, with an incidence rate of 76.8 (95% CI=66.8-88.4) per 1,000 person-years. Approximately half of prevalent and incident MCI cases had memory impairment. Compared with normal cognition, multivariable-adjusted risk for progression from MCI with memory impairment to dementia was 4.78 (95% CI=2.78-8.07) for any dementia, 5.92 (95% CI=3.20-10.91) for AD, and 1.61 (95% CI=0.37-7.00) for VaD. No association with dementia risk was found for MCI without memory impairment. Approximately one-third of MCI cases with memory impairment did not progress to dementia. MCI occurs often in this elderly Italian cohort and is associated with greater risk of AD, but only when the impairment involves the memory domain. However, a substantial proportion of MCI cases with memory impairment do not progress to dementia.

The development of performance and cost indicators for preschool immunisation.

The organisation, premises, and staffing of three child health clinics of different types in an inner city area have been studied and related to information on immunisation derived from their computerised child register and other returns, together with some simple estimates of cost. Differences were found between overall uptake of different antigens, consent rate, compliance after consent had been given, and the median age at immunisation for children allocated to each clinic. Thus consent to pertussis immunisation varied from 90% in one clinic to 69% in the other two. In the clinic with the high consent rate, however, only 66% of those whose parents had consented actually received all three doses compared with 82% and 85% in the other clinics. The median age of immunisation also showed pronounced differences between the clinics--314, 351, and 375 days, respectively, for the third dose of the triple course. There were differences in characteristics of the clientele served by each clinic and in staffing and facilities, which led to differences in costs, as well as contributing towards the variable patterns of uptake. We suggest that indicators such as these, largely available from the child health computer system, are used systematically to identify ways of improving uptake and increasing cost effectiveness.

Depression of cellular immunity as an index of malnutrition in surgical patients

Definitions of mild cognitive impairment (MCI) vary, yielding conflicting results. For example, case definitions affect prevalence but not outcomes in prevalent cases. Our objective was to determine whether variation in case definitions affects outcomes in incident cases of MCI. The 5 year risks of death, institutionalisation, and dementia were evaluated in clinically examined incident MCI cases in the Canadian Study of Health and Aging. The definition of MCI was varied so as to include or relax combinations of diagnostic features from consensus criteria. Relative risks (RR) of each adverse outcome were highest in MCI case definitions that required subjective memory complaints (for example, RR of dementia = 26.4–38.7). Although each MCI definition conferred an increased risk of dementia, for each case definition 20–30% of survivors had no cognitive impairment at follow up. In this population based study, MCI represented a transitional state, but was heterogeneous, with substantial proportions recovering, regardless of how MCI was defined. Factors associated with recovery and non-progression in MCI require elucidation.