Gwenith G. Fisher

Prevalence of Dementia in the United States: The Aging, Demographics, and Memory Study

Aim: To estimate the prevalence of Alzheimer’s disease (AD) and other dementias in the USA using a nationally representative sample. Methods: The Aging, Demographics, and Memory Study sample was composed of 856 individuals aged 71 years and older from the nationally representative Health and Retirement Study (HRS) who were evaluated for dementia using a comprehensive in-home assessment. An expert consensus panel used this information to assign a diagnosis of normal cognition, cognitive impairment but not demented, or dementia (and dementia subtype). Using sampling weights derived from the HRS, we estimated the national prevalence of dementia, AD and vascular dementia by age and gender. Results: The prevalence of dementia among individuals aged 71 and older was 13.9%, comprising about 3.4 million individuals in the USA in 2002. The corresponding values for AD were 9.7% and 2.4 million individuals. Dementia prevalence increased with age, from 5.0% of those aged 71–79 years to 37.4% of those aged 90 and older. Conclusions: Dementia prevalence estimates from this first nationally representative population-based study of dementia in the USA to include subjects from all regions of the country can provide essential information for effective planning for the impending healthcare needs of the large and increasing number of individuals at risk for dementia as our population ages.

Prevalence of depression among older Americans: the Aging, Demographics and Memory Study.

BACKGROUND Previous studies have attempted to provide estimates of depression prevalence in older adults. The Aging, Demographics and Memory Study (ADAMS) is a population-representative study that included a depression assessment, providing an opportunity to estimate the prevalence of depression in late life in the U.S.A. METHODS The ADAMS sample was drawn from the larger Health and Retirement Study. A total of 851 of 856 ADAMS participants aged 71 and older had available depression data. Depression was measured using the Composite International Diagnostic Interview - Short Form (CIDI-SF) and the informant depression section of the Neuropsychiatric Inventory (NPI). We estimated the national prevalence of depression, stratified by age, race, sex, and cognitive status. Logistic regression analyses were performed to examine the association of depression and previously reported risk factors for the condition. RESULTS When combining symptoms of major or minor depression with reported treatment for depression, we found an overall depression prevalence of 11.19%. Prevalence was similar for men (10.19%) and women (11.44%). Whites and Hispanics had nearly three times the prevalence of depression found in African-Americans. Dementia diagnosis and pain severity were associated with increased depression prevalence, while black race was associated with lower rates of depression. CONCLUSIONS The finding of similar prevalence estimates for depression in men and women was not consistent with prior research that has shown a female predominance. Given the population-representativeness of our sample, similar depression rates between the sexes in ADAMS may result from racial, ethnic and socioeconomic diversity.

A Lengthy Look at the Daily Grind: Time Series Analysis of Events, Mood, Stress, and Satisfaction

The present study investigated processes by which job stress and satisfaction unfold over time by examining the relations between daily stressful events, mood, and these variables. Using a Web-based daily survey of stressor events, perceived strain, mood, and job satisfaction completed by 14 university workers, 1,060 occasions of data were collected. Transfer function analysis, a multivariate version of time series analysis, was used to examine the data for relationships among the measured variables after factoring out the contaminating influences of serial dependency. Results revealed a contrast effect in which a stressful event associated positively with higher strain on the same day and associated negatively with strain on the following day. Perceived strain increased over the course of a semester for a majority of participants, suggesting that effects of stress build over time. Finally, the data were consistent with the notion that job satisfaction is a distal outcome that is mediated by perceived strain.

Incidence of dementia and cognitive impairment, not dementia in the United States.

Estimates of incident dementia, and cognitive impairment, not dementia (CIND) (or the related mild cognitive impairment) are important for public health and clinical care policy. In this paper, we report US national incidence rates for dementia and CIND.

Latent variable analyses of age trends of cognition in the health and retirement study, 1992-2004

The present study was conducted to better describe age trends in cognition among older adults in the longitudinal Health and Retirement Study (HRS) from 1992 to 2004 (N = 17,000). The authors used contemporary latent variable models to organize this information in terms of both cross-sectional and longitudinal inferences about age and cognition. Common factor analysis results yielded evidence for at least 2 common factors, labeled Episodic Memory and Mental Status, largely separable from vocabulary. Latent path models with these common factors were based on demographic characteristics. Multilevel models of factorial invariance over age indicated that at least 2 common factors were needed. Latent curve models of episodic memory were based on age at testing and showed substantial age differences and age changes, including impacts due to retesting as well as several time-invariant and time-varying predictors.

Developing and investigating the use of single-item measures in organizational research.

The validity of organizational research relies on strong research methods, which include effective measurement of psychological constructs. The general consensus is that multiple item measures have better psychometric properties than single-item measures. However, due to practical constraints (e.g., survey length, respondent burden) there are situations in which certain single items may be useful for capturing information about constructs that might otherwise go unmeasured. We evaluated 37 items, including 18 newly developed items as well as 19 single items selected from existing multiple-item scales based on psychometric characteristics, to assess 18 constructs frequently measured in organizational and occupational health psychology research. We examined evidence of reliability; convergent, discriminant, and content validity assessments; and test-retest reliabilities at 1- and 3-month time lags for single-item measures using a multistage and multisource validation strategy across 3 studies, including data from N = 17 occupational health subject matter experts and N = 1,634 survey respondents across 2 samples. Items selected from existing scales generally demonstrated better internal consistency reliability and convergent validity, whereas these particular new items generally had higher levels of content validity. We offer recommendations regarding when use of single items may be more or less appropriate, as well as 11 items that seem acceptable, 14 items with mixed results that might be used with caution due to mixed results, and 12 items we do not recommend using as single-item measures. Although multiple-item measures are preferable from a psychometric standpoint, in some circumstances single-item measures can provide useful information.

Beyond Work and Family: A Measure of Work/Nonwork Interference and Enhancement

Though early research on the work/nonwork interface was broader in scope, most recent research has focused on the interface between work and family. There is a need for an inclusive, validated measure of work/nonwork interference and enhancement that is appropriate for all workers regardless of their marital or family life status. The authors report here on 3 studies in which they develop a theoretically grounded and empirically validated multidimensional, bidirectional measure of work/nonwork interference and enhancement. All scale items refer to work/nonwork, whereas previous measures have mixed work/family and work/nonwork items or emphasize family roles in the nonwork domain. Quantitative analysis of the scale items yielded 17 items to measure work interference with personal life, personal life interference with work, work enhancement of personal life, and personal life enhancement of work. Confirmatory factor analyses and structural equation modeling results provide evidence for convergent, discriminant, and criterion-related validity for the scale from 2 large samples of workers (N = 540, N = 384) across multiple job types and organizations.

Development of a Compact Measure of Job Satisfaction: The Abridged Job Descriptive Index

The Job Descriptive Index is a popular measure of job satisfaction with five subscales containing 72 items. A national sample (n = 1,534) and a sample of university workers (n = 636) supported development of an abridged version of the Job Descriptive Index (AJDI) containing a total of 25 items. A systematic scale-reduction technique was employed with the first sample to decide which items to retain in each scale. The abridged subscales were then tested in the second sample. Results indicated that the relationships among the five abridged subscales and between the five abridged subscales and other measures were substantially preserved.

Age Differences in the Demand–Control Model of Work Stress: An Examination of Data From 15 European Countries

There have been many tests of Karasek’s demand—control model of work stress. However, no studies have examined how the model may differentially apply to older versus younger workers. Due to age changes in cognitive processing, the psychological demands of jobs may interact differently with controls for younger versus older workers. Therefore, the study uses data from the Eurobarometer to examine how the demand—control model of work stress may function differently for older versus younger workers. The results indicate that different controls may in fact buffer different types of job demands for younger versus older workers. The findings reveal that only the interaction between problem solving and time to complete tasks was significant for younger workers. For older workers, however, the interactions between time deadlines and having sufficient time to complete tasks, autonomy, and the interaction between problem solving and schedule flexibility are significant predictors of self-reported stress.

Mental Work Demands, Retirement, and Longitudinal Trajectories of Cognitive Functioning

Age-related changes in cognitive abilities are well-documented, and a very important indicator of health, functioning, and decline in later life. However, less is known about the course of cognitive functioning before and after retirement and specifically whether job characteristics during ones time of employment (i.e., higher vs. lower levels of mental work demands) moderate how cognition changes both before and after the transition to retirement. We used data from n = 4,182 (50% women) individuals in the Health and Retirement Study, a nationally representative panel study in the United States, across an 18 year time span (1992-2010). Data were linked to the O*NET occupation codes to gather information about mental job demands to examine whether job characteristics during ones time of employment moderates level and rate of change in cognitive functioning (episodic memory and mental status) both before and after retirement. Results indicated that working in an occupation characterized by higher levels of mental demands was associated with higher levels of cognitive functioning before retirement, and a slower rate of cognitive decline after retirement. We controlled for a number of important covariates, including socioeconomic (education and income), demographic, and health variables. Our discussion focuses on pathways through which job characteristics may be associated with the course of cognitive functioning in relation to the important transition of retirement. Implications for job design as well as retirement are offered.