Trajectory classes of depressive symptoms in a community sample of older adults.

OBJECTIVE: To identify trajectories of depressive symptoms in older community residents. METHOD: Depressive symptomatology, based on a modified Center for Epidemiological Studies-Depression scale, was obtained at years 0, 3, 6, and 10, in the Duke Established Populations for Epidemiologic Studies of the Elderly (n = 4162). Generalized growth mixture models identified the latent class trajectories present. Baseline demographic, health, and social characteristics distinguishing the classes were identified using multinomial logistic regression. RESULTS: Four latent class trajectories were identified. Class 1 - stable low depressive symptomatology (76.6% of the sample); class 2 - initially low depressive symptomatology, increasing to the subsyndromal level (10.0%); class 3 - stable high depressive symptomatology (5.4%); class 4 - high depressive symptomatology improving over 6 years before reverting somewhat (8.0%). Class 1 was younger, male gender, with better education, health, and social resources, in contrast to class 3. Class 2 had poorer cognitive functioning and higher death rate. Class 4 had better health and social resources. CONCLUSION: Reduction in high depressive symptomatology is associated with more education, better health, fewer stressful events, and a larger social network. Increasing depressive symptomatology is accompanied by poorer physical and cognitive health, more stressful life events, and greater risk of death.

Increased health burden associated with comorbid depression in older Brazilians with diabetes.

BACKGROUND: The health burden associated with comorbid depression and diabetes in older community residents in middle income countries is unclear. METHODS: Data came from a statewide representative sample (N = 6963, age ≥ 60) in Brazil. Controlled polytomous logistic regression was used to determine whether four mutually exclusive groups (all possible combinations of the presence or absence of depression and diabetes) differed in sociodemographic characteristics, social resources, health behaviors, and selected health conditions. RESULTS: While 2.37% were expected to have comorbid depression/diabetes given sample base rates (depression: 20.92% [1457/6963]; diabetes: 11.35% [790/6959]), comorbidity was present in 3.62% (52.5% beyond expectation; P<0.0001; OR = 1.58, 95% Confidence Interval 1.29-1.95). Depression without diabetes was reported by 17.3%, and diabetes without depression by 7.7%. In controlled analyses, the depression group had poorer socioeconomic status and health behaviors, and a greater likelihood of vascular, respiratory, and musculoskeletal problems than the diabetes group. Vascular, respiratory, and urinary problems were exacerbated in comorbid depression/diabetes; the comorbid group was also more likely to be female and younger. LIMITATIONS: Cross-sectional design. CONCLUSIONS: To our knowledge, this is the first study that explicitly reports on all four possible depression/diabetes combinations in an older representative community-resident sample, using controlled analyses to identify unique associations with sociodemographic characteristics and other health conditions. The burden of comorbid depression/diabetes in Brazil, a middle income country, appears to be comparable to that found in higher income countries. So, similarly, depression without diabetes had a greater odds of adverse sociodemographic and health conditions than diabetes without depression; comorbid depression/diabetes was more likely in women and young elderly, and the odds of vascular, respiratory, and urinary conditions was increased significantly. Attention to comorbid depression/diabetes as a unique entity is needed.

Modeling association in longitudinal binary outcomes: a brief review.

In order to better understand aging, longitudinal studies are run in which participants are evaluated repeatedly and selected end-points (e.g., score on a cognitive screen, falls, occurrence/reoccurrence of a condition) are examined. The objective of the present paper is primarily to describe the methods available that take into account correlation between binary outcomes, and in particular to model the association of binary outcomes after controlling for covariates by using an implementation of generalized estimating equations (GEE) called 'alternating logistic regression' (ALR). In GEE, association within longitudinal outcomes is accounted for but not estimated. Alternating logistic regression, however, basically enables simultaneous estimation of pair-wise odds ratios of outcomes within a cluster, while accounting for the dependence of the outcome on covariates. A sub-sample (n=2458) from a community-based sample of Duke Established Populations for Epidemiologic Studies of the Elderly is used. In the example used here, logistic regression using GEE and ALR is used to model binary outcomes at three time points (baseline, three and six years later) and to control for covariates in a representative community-based sample 65 years of age and older (n=2458). The outcomes indicate any problem versus no problem on a five-item activities of daily living (ADL) scale in a community sample. The ALR model, however, provides insight into decline in ADL from baseline to each of the time-points whereas GEE does not. In both controlled and uncontrolled analyses, decline in ADL over three and six-year intervals (baseline to three years later, baseline to six years and three years post-baseline to six years post-baseline) is significant.

Comparison of methods for analyzing longitudinal binary outcomes: cognitive status as an example.

Longitudinal data generate correlated observations. Ignoring correlation can lead to incorrect estimation of standard errors, resulting in incorrect inferences of parameters. In the example used here, standard logistic regression, a population-averaged (PA) model fit using generalized estimating equations (GEE), and random-intercept models are used to model binary outcomes at baseline, three and six years later. The outcomes indicate cognitive impairment versus no cognitive impairment in a sample of community dwelling elders. The models include both time-invariant (age, gender) and time-varying (time, interactions with time) covariates. The absolute estimates from random-intercept models are larger than those of both standard logistic and GEE models. Compared to the model fit using GEE that accounts for time dependency, standard logistic regression models overestimate standard errors of time-varying covariates (such as time, and time by problems with activities of daily living), and underestimate the standard errors of time-invariant covariates (such as age and gender). The standard errors from the random-intercept model are larger than those from logistic regression and GEE models. The choice of models, GEE or random-intercept, depends on the research question and the nature of the covariates. Population-averaged methods are appropriate when between-subjects effects are of interest, and random-effects are useful when subject-specific effects are important.

Alternative statistical approaches to identifying dementia in a community-dwelling sample.

Little attention has been paid to examining the extent to which alternative statistical models may facilitate identification of persons with dementia. Using a sub-sample of the Duke Established Populations for Epidemiologic Studies of the Elderly, two analytical approaches were compared: logistic regression (which focuses on identifying specific characteristics predictive here of dementia), and recursive partitioning methods using tree-based models (which permit identification of the characteristics of those groups with high dementing disorder). In the stepwise multiple logistic regression model which included as potential predictors, gender, age, history of chronic health conditions, scales of basic and instrumental activities of daily living (IADL), and cognitive status, only IADL and cognitive status were significant predictors, with cognitive status the single most important factor. The classification tree approach, which permits identification of the characteristics of those groups with particularly high dementia rates, identified cognitive status as the most important criterion for dementia (as did logistic regression analysis). Among those without cognitive impairment, older age was a risk factor, confirming findings consistently reported in the literature. Among the cognitively impaired, IADL was an important risk factor. Those with five or more IADL problems were further classified into two risk groups, based on number of ADL problems. While classification tree analysis encourages identification of groups at risk, logistic regression encourages targeting of specific characteristics.

The relationship of APOE genotype to cognitive functioning in older African-American and Caucasian community residents.

OBJECTIVES: To determine whether cognitive decline associated with the apolipoprotein E (APOE) epsilon4 allele is different in older African Americans than it is in Caucasians. DESIGN: Performance on a brief screen of cognitive functioning was examined at baseline (N = 1,891) and 4 years later (N = 1,389) to determine the extent to which the presence of APOE epsilon4 affected level of and change in performance, and whether this differed as a function of race, age, initial score, and change in score. SETTING: Five adjacent counties in the Piedmont area of North Carolina. PARTICIPANTS: In 1986, a stratified random household sample of community residents age 65 and older (n = 4,162; 54% African-American, 45% Caucasian, 1% other race) formed the Duke Established Populations for Epidemiologic Studies of the Elderly. Of those available at the sixth annual wave, 76% were genotyped, with 1,891 providing baseline data on this wave, and the available survivors (n = 1,389) providing longitudinal data 4 years later. MEASUREMENTS: The Short Portable Mental Status Questionnaire (SPMSQ), a brief screen of cognitive functioning, was administered to all subjects on both occasions. We examined score at baseline and cognitive decline (i.e., increase of 2+ errors) at follow-up. Control measures included demographic characteristics, health behaviors, health and functional status, and medication use. APOE status was coded as epsilon4 present versus absent. RESULTS: APOE epsilon4 was significantly and uniquely related to lower score at baseline and significantly increased the odds of cognitive decline by 59%. There was no statistically significant interaction between APOE epsilon4 and age, race, initial SPMSQ score, or SPMSQ score at follow-up. CONCLUSION: APOE epsilon4 is modestly, if significantly, related to poorer cognitive functioning and to decline in cognitive functioning. No differences were found by age or race in this community representative sample.

Performance of elderly African American and White community residents on the CERAD Neuropsychological Battery.

The CERAD Neuropsychological Battery, includes 7 measures: Verbal Fluency; Modified Boston Naming; Mini-Mental State: Word List Learning, Recall and Recognition; Constructional Praxis. It was originally developed to evaluate patients with a clinical diagnosis of Alzheimer's disease, but is increasingly used in epidemiological studies of the incidence and prevalence of dementia in the elderly. The current study reports norms for African American and White representative community residents 71 years of age and older in North Carolina, and compares performance with that of African Americans in Indianapolis and with Whites in the Monongahela Valley, Pennsylvania. For all 3 studies, increased education and younger age was related to better performance on each of the 7 measures. Sex differences, when present, tended to favor women. Although on average African Americans performed more poorly than Whites, with demographic characteristics controlled, no significant racial differences were found in the North Carolina sample. Both African American and White participants in North Carolina performed more poorly than their racial counterparts in the other 2 studies, possibly because of selection-induced differences in health and educational status. Nevertheless, the use of an identical evaluation battery, such as the CERAD neuropsychologic instrument, facilitates comparisons not otherwise possible, and should be encouraged.

In-home assessment of dementia by nurses: experience using the CERAD evaluations. Consortium to Establish a Registry for Alzheimer's Disease.

PURPOSE OF STUDY: To maximize respondent participation in a study of the prevalence, incidence, and natural history of dementia. DESIGN AND METHODS: Clinical research nurses were trained to carry out evaluations for dementia in the home. We describe the assessment and training procedures used and note the advantages and drawbacks of this approach. RESULTS: Nurse identification of the presence of dementia agreed well with that of medical specialists (kappa = 0.84), but was slightly poorer regarding type of dementia (kappa = 0.71). IMPLICATIONS: Use of nurses for such activity need not be limited to epidemiological studies, but is relevant also in clinical practice.

Epidemiology of over-the-counter drug use in community dwelling elderly: United States perspective.

Among US community dwelling individuals aged > or = 65 years, about as many persons take nonprescription drugs as take prescription drugs. A review of US data from the last 2 decades indicates that the average number of over-the-counter (OTC) drugs taken daily is around 1.8, but varies with geographical area (highest in the Midwest) and race/ethnicity (lowest use among Hispanics, followed by African Americans. and highest use among Whites). Use has consistently been found to be higher in women than in men. While OTC use appears to be increasing over time, it also decreases with increase in age. The most common OTC classes used are analgesics, laxatives and nutritional supplements. Our ability to explain or to predict OTC use and change in use is poor, and further studies, particularly on use by elderly individuals of minority races, are needed.

Impact of estrogen use on decline in cognitive function in a representative sample of older community-resident women.

The authors investigated whether postmenopausal estrogen use helps to maintain cognitive function; a brief screen, the Short Portable Mental Status Questionnaire (SPMSQ), was used. Information was gathered from a stratified, random sample of 1,907 African-American and White women (aged 65-100 years) participating in the longitudinal Duke Established Populations for Epidemiologic Studies of the Elderly project carried out in five urban and rural counties of North Carolina. All women were cognitively unimpaired in 1986-1987 and were evaluated 3 and 6 years later. Decline in cognitive function was measured as an increase of two or more errors on the SPMSQ and crossing of an SPMSQ threshold indicative of cognitive impairment. Recency and continuity of estrogen use were measured. Univariate analyses indicated that recent (crude odds ratio = 0.42, 95% confidence interval: 0.21, 0.86) and continuous (crude odds ratio = 0.32, 95% confidence interval: 0.13, 0.81) estrogen use reduced the risk of cognitive decline but not of cognitive impairment. After adjustment for demographic and health characteristics, protective effects became nonsignificant. While postmenopausal use of estrogen may be protective for Alzheimer's disease, current findings based on a brief cognitive screen suggest that it is not protective for cognitive decline related to aging.

The effect of race and health-related factors on naming and memory. The MacArthur Studies of Successful Aging.

OBJECTIVES: The purpose of the analyses was to examine the impact of health-related variables on race differences in neuropsychological functioning (Boston Naming Task). METHODS: Using cross-sectional data from the MacArthur Successful Aging Study, the authors examined the relationship of demographic characteristics, health status, health habits, physical functioning, and speed of performance to naming and incidental recall of items from the Boston Naming Task. Participants were 1,175 healthy African American and European American older persons 70 to 79 years old. RESULTS: Regression analyses indicated that although race differences persisted for confrontational naming after controlling for demographic and health factors, there was no effect due to race for incidental recall scores or for savings scores for recall. DISCUSSION: The racial differences found in test performance may reflect differences in cultural appropriateness of the material rather than differences in ability.

Inappropriate drug use among community-dwelling elderly.

This study examined inappropriate drug use defined by updated criteria among respondents in the second and third in-person waves of the Duke Established Populations for Epidemiologic Studies of the Elderly. Information about sociodemographics, health status, access to health care, and drug use was determined by in-home interviews. Drug use was coded for therapeutic class and appropriateness by applying explicit criteria. Among participants, 27% of the second and 22.5% of the third in-person wave took one or more inappropriate agents. Of these drugs, the most common therapeutic classes were central nervous system and cardiovascular. Longitudinal multivariate analyses found that persons taking several prescription drugs, those having continuity of care, those who previously took inappropriate drugs, and those with many health visits were most likely (p<0.05) to use inappropriate drugs. We conclude that inappropriate drug use is common among community-dwelling elderly.

Comorbidity of five chronic health conditions in elderly community residents: determinants and impact on mortality.

BACKGROUND: Comorbidity is common in elderly persons. Its extent, correlates, and life-threatening impact in representative community residents are unclear. METHODS: Self-reported information of physician-diagnosed coronary artery disease (CAD), cerebrovascular disease (CVD), diabetes, and cancer was obtained annually between 1986-87 and 1992-93, and hypertension was obtained triennially from the participants of the Duke Established Populations for Epidemiologic Studies of the Elderly, a stratified multistage sample of 4,126 Black and White community residents aged 65-100, living in a five-county area of North Carolina. Date of death was obtained from death certificates identified through search of the National Death Index. Statistical procedures included descriptive statistics, logistic regression, and survival analysis. RESULTS: Of this sample, 57% reported hypertension, 20% diabetes, 15% CAD, 9% cancer, and 9% CVD; 29% reported none of these conditions, whereas 29% reported two or more. Demographic characteristics were not related to comorbidity with CVD or cancer. Increased education tended to be protective. The effect of age, gender, and race varied with condition. At baseline there was substantial comorbidity among hypertension, CAD, CVD, and diabetes, but not with cancer. Hypertension, CVD, and diabetes were risk factors for CAD, whereas diabetes was a risk factor for CVD. After controlling for demographic characteristics, all health conditions except hypertension were predictive of 6-year mortality, as was the presence of comorbidity. CONCLUSION: We found significant comorbidity in older persons who have hypertension, CAD, CVD, or diabetes; particular risk of developing comorbidity, particularly CAD, among those with hypertension, CVD, and diabetes; and risk of CVD in those with diabetes. With the exception of hypertension, these conditions, and comorbidity per se, are life-threatening.

Determinants of attrition in a natural history study of Alzheimer disease.

The aim of the present study was to identify determinants of attrition in a natural history study of a tertiary care sample of patients with Alzheimer disease (AD) and control subjects. A longitudinal study was performed with 978 patients with AD and 466 control subjects age 50 years and older enrolled at 25 sites of the Consortium to Establish a Registry for Alzheimer's Disease between January 1987 and January 1992; subjects were followed annually for up to 78 months. Both descriptive statistics and polytomous logistic regressions were run to identify determinants of attrition. Of the 1,444 subjects enrolled, 10.5% dropped out after initial evaluation, 31.0% provided at least two waves of data, and 58.4% provided complete follow-up. Inadequate involvement by the site, non-white status, and patient's spouse not enrolled in the study were predictive of dropout; cessation of participation because of death (which may have precluded dropout) predicted continuation in the study. Age, level of education, severity of dementia, and rapidity of progression of disease did not predict dropout. Level-of-site commitment was the most significant determinant of continued participation in this natural history study of AD, followed by white race, and the inclusion of both husband and wife where one is a patient and the other a control subject.

Variability in annual Mini-Mental State Examination score in patients with probable Alzheimer disease: a clinical perspective of data from the Consortium to Establish a Registry for Alzheimer's Disease.

OBJECTIVE: To determine the variability in annual Mini-Mental State Examination scores of patients with Alzheimer disease enrolled in the Consortium to Establish a Registry for Alzheimer's Disease (CERAD). PATIENTS: A total of 372 patients with probable Alzheimer disease with 1 or more years of follow-up. SETTING: Twenty-one CERAD clinical sites throughout the United States. RESULTS: An average annual decline of 3.4 points in CERAD patients returning for longitudinal reassessments was close to the SD of the measurement error of 2.8 points for the Mini-Mental State Examination. There was wide variability in individual rates of decline. Even with 4 years of follow-up, 15.8% of the patients had no clinically meaningful decline in Mini-Mental State Examination score (defined as a change in initial score >3, ie, 1 SD of measurement error). Validity of measurements of the rate of change in Mini-Mental State Examination scores improved with longer observation intervals and was reliable for most patients when observations were separated by 3 or more years. CONCLUSIONS: Although the Mini-Mental State Examination is a useful screening instrument to assess level of cognitive function, it has limited value in measuring the progression of Alzheimer disease in individual patients for periods less than 3 years because of a large measurement error and substantial variation in change in annual score.

Development of an activities of daily living scale to screen for dementia in an illiterate rural older population in India.

OBJECTIVE: to develop a measure of activities of daily living appropriate for use in assessing the presence of dementia in illiterate rural elderly people in India. DESIGN: identification of relevant items, pre-testing of items and refinement of administrative procedures and scoring in four successive groups of 30 subjects each, pilot testing in a group of 100 subjects comparable to those for whom the measure is intended, administration to a representative sample of 387 people aged 55 and older, and assessment of the reliability of the final measure. SETTING AND SUBJECTS: age-stratified random sample of older men and women in rural areas of Ballabgarh, Northern India. RESULTS: the original pool of 35 items covering mobility, instrumental and personal care activities was reduced to an 11-item unidimensional scale (to which an additional item on mobility was added) with internal consistency (Cronbach's alpha)=0.82, perfect inter- and intra-rater reliability, test-retest reliability (intraclass correlation)=0.82 (any disability) and 0.92 (unable to perform for 'mental' reasons). Women, older subjects, the totally illiterate and subjects with poorer cognitive function performed significantly more poorly (P < or = 0.02 for all). PRODUCT: a brief, reliable and valid activities of daily living measure, with norms, which is appropriate for use in assessing dementia in illiterate rural elderly people in India.

Comparison of Lewy body variant of Alzheimer's disease with pure Alzheimer's disease: Consortium to Establish a Registry for Alzheimer's Disease, Part XIX.

OBJECTIVE: To compare the clinical, neuropsychological, and neuropathologic findings in patients with AD alone with those in patients with the Lewy body variant of AD (LBV). BACKGROUND: Prior studies indicate that patients with LBV not only have distinct clinical and neuropsychological differences from those with AD alone, but have a poorer prognosis with shorter survival time. METHODS: The authors evaluated 74 patients with autopsy-confirmed AD alone and 27 patients with LBV, and compared demographic characteristics and clinical, neuropsychological, and neuropathologic findings. RESULTS: The two groups of patients were equivalent with respect to age at time of entry into the study, years of education, and sex. Two or more extrapyramidal clinical manifestations were found in 44% of patients with LBV, compared with 16% of patients with AD alone (p = 0.02). Duration of survival after entry into the study was similar in both groups, with a mean survival of 3.6 (+/-2.1) years for AD alone versus 3.8 (+/-1.9) years for LBV. Of the various neuropsychological tests administered at the last Consortium to Establish a Registry for Alzheimer's Disease evaluation, only delayed recall of a learned word list was significantly different in the two groups, with 32% of patients with LBV versus 15% of patients with AD alone recalling any items (p = 0.04). Neuropathologic findings confirmed those of previous studies and showed that neurofibrillary tangles were significantly less frequent in the neocortex of patients with LBV than in those with AD alone. CONCLUSION: Compared with patients with AD alone, those with LBV had a greater frequency of extrapyramidal manifestations, somewhat better recall on a selected memory task at their final evaluation, and a significantly lower frequency of neocortical neurofibrillary tangles at autopsy. There were no differences between the two groups, however, in survival time from entry into the study.

Equivalence of two screens of cognitive functioning: the Short Portable Mental Status Questionnaire and the Orientation-Memory-Concentration test.

OBJECTIVE: To determine the equivalence of two screens of cognitive functioning: the Short Portable Mental Status Questionnaire (SPMSQ) and the Orientation-Memory-Concentration (OMC) test. DESIGN: The design was cross-sectional and longitudinal. SETTING: Four rural and one urban county in the Piedmont region of North Carolina (n = 3210). PARTICIPANTS: A stratified random cluster sample (n = 3210) of people 68 years of age and older. MEASUREMENTS: SPMSQ and OMC at the fourth wave of the Duke Established Populations for Epidemiologic Studies of the Elderly (EPESE); disability, depression, and death measurements from the fourth through seventh waves of EPESE; demographic characteristics. RESULTS: On the SPMSQ and the OMC (r = .80), 15.3% and 38.4%, respectively, of those tested were rated cognitively impaired. Poorer scores were associated with older age, black race, and less education. These associations were attenuated on the dichotomized SPMSQ but not on the OMC. Both measures predicted disability and depressive symptomatology currently and 3 years hence and death. CONCLUSIONS: The SPMSQ and OMC, although highly correlated, are not equivalent. Association with race and education are greater for the OMC, whereas an association with age exists for both measures. The milder level of impairment identified by the OMC increases predictive capacity.

Private health insurance coverage and disability among older Americans.

OBJECTIVES: This study examines the relationship between the lack of private supplemental health insurance coverage and the development of disability among adults aged 65 and older. METHODS: Data are from the baseline and six follow-up waves of the Duke Established Populations for Epidemiologic Studies of the Elderly survey (N = 4,000). Discrete-time hazard models were used to estimate the impact of insurance coverage and other risk factors on the incidence of disability among those unimpaired at baseline. RESULTS: Controlling for education, income, and other potential confounders, the odds of developing disability were 35-49% higher among those without private coverage. Insurance coverage also statistically explained part of the increased risk of disability among low-income persons. DISCUSSION: The results indicate that changes in health insurance coverage as well as in individual behaviors may be needed to reduce disability generally and disability among the socioeconomically disadvantaged, in particular.

Progression of Alzheimer's disease in black and white patients: the CERAD experience, part XVI. Consortium to Establish a Registry for Alzheimer's Disease.

We compared the progression of Alzheimer's disease (AD) in CERAD-enrolled black and white patients, as indicated by changes in selected clinical and neuropsychology measures, over a 1-year time interval. Of 225 black and 935 white AD patients who were enrolled, 148 (66%) black and 770 (82%) white patients remained in the study. Of these, 82 black and 532 white patients provided complete in-person information on first annual re-evaluation. Overall, with age, education, initial level of performance on each measure, and stage of disease at entry controlled, race had a very mild effect on change in disease (8 df multivariate analysis of variance [MANOVA], p < 0.047). Black patients showed less decline than white patients, most notably for the CERAD Boston Naming test (p < 0.02) and the third and final trial of the 10-item Word List Learning task (p < 0.003). Although unadjusted data indicate that black and white patients appear to differ notably at entry, our findings indicated that differences in progression of the dementing process are minor, suggesting that course of AD is comparable in these racial groups. Examination over a longer period is difficult because of the high attrition rate of black patients.