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.

The complex relationship between depressive symptoms and functional limitations in community-dwelling older adults: the impact of subthreshold depression.

BACKGROUND: Depressive symptoms above screening thresholds have been shown to predict functional decline in older adults. Less is known about the impact of subthreshold depression, and whether more symptoms confer significantly greater risk compared to fewer symptoms. METHOD: Using data from the Duke Established Populations for Epidemiologic Studies of the Elderly (EPESE) collected over 10 years, we used repeated-measures mixed models to predict functional change by depression status at the prior (index) in-person interview. Depressive symptoms were measured using a modified version of the Center for Epidemiologic Studies Depression Scale (CES-D). Subthreshold depression was operationalized as 6-8 symptoms and CES-D-defined depression as 9-20 symptoms in the previous week. Three domains of functional status were assessed at the subsequent in-person interview: limitations in basic activities of daily living (ADL), instrumental ADL (IADL) and mobility. RESULTS: Controlling for race, sex, age, education, marital status, cognitive status, health status, self-perceived health, perceived social support and functional status at the index interview, having 6 depressive symptoms predicted an increase of 0.12 IADL limitations 3-4 years later (p=0.03). The incremental effect of CES-D-defined depression (9 symptoms compared to 6-8 symptoms) was not significant, suggesting that the effect of more symptomatic depression did not add to that of subthreshold depression. CES-D score modeled as a continuous variable predicted functional change for all domains, but the relationship was not linear, supporting a possible threshold effect. CONCLUSIONS: The relationship between depressive symptoms and functional change is complex, not necessarily linear, and may vary by tasks assessed.

Marked differences in antidepressant use by race in an elderly community sample: 1986-1996.

OBJECTIVE: Prescriptions of antidepressant medications have increased significantly over the past 15 years across the life cycle. One overall correlate of medication use in older adults is race, with African Americans using fewer medications than whites. Given the frequency of depressive symptoms among elderly populations, as well as the increased potential for adverse side effects from antidepressants, the relative contribution of race in the use of antidepressants is critical for determining well-designed studies. The authors analyzed data from a community-based cohort of elders followed for 10 years to determine the association of race to the use of antidepressants between 1986 and 1996, with control for known correlates of depression in late life. METHOD: Information on antidepressant use and demographic and health characteristics were obtained from a stratified, probability-based sample of 4,162 elders (equally distributed between African American and white community-dwelling subjects) in the Piedmont region of North Carolina during four in-person interviews spanning 10 years. Descriptive statistics were calculated. Logistic regression was used for the final models. RESULTS: A total of 4.6% of whites and 2.3% of African Americans used antidepressants in 1986. Approximately 14.3% of whites and 5.0% of African Americans used antidepressants in 1996. In controlled analyses, the prevalence odds ratio for antidepressant use in whites, compared to African Americans, was 1. 76 in 1986 and 3.77 in 1996. CONCLUSIONS: African American elders are much less likely to take antidepressants, and the difference in use increased over the 10 years of the survey.

The association of depression and mortality in elderly persons: a case for multiple, independent pathways.

BACKGROUND: The evidence for an association between depression and mortality among community-dwelling elderly persons remains inconclusive, although it is well established for younger individuals. Extant studies suggest that this association weakens when adjusted for potential confounding factors, especially functional impairment. A cohort of elderly subjects followed for 3 years was analyzed to determine the association of depression and 3-year mortality, controlling for the major known risk factors for mortality in the elderly population. METHODS: Information on depression (CES-D scores), mortality, demographics, body mass index, chronic disease, smoking history, cognitive impairment, functional impairment, self-rated health, and social support was obtained from a stratified probability-based sample of community-dwelling elderly persons, with equal distribution between African Americans and whites in the Piedmont of North Carolina. Descriptive statistics were calculated, and logistic regression was used for a series of models with progressively more control variables. RESULTS: The unadjusted relative odds of mortality among depressed subjects at baseline was 1.98 over 3 years of follow-up. Inclusion of age, gender, and race into the model did not reduce the relative odds. When chronic disease and health habits, cognitive impairment, functional impairment, and social support were added to the model, the odds ratios for mortality with depression were 1.74, 1.69, 1.29, and 1.21, respectively. This decrease in odds ratios was not observed for other variables in the model when additional variables were added. CONCLUSIONS: The estimated odds of dying if depressed moved toward unity as other risk factors for mortality were controlled. Unlike other known risk factors for mortality in the elderly population, depression appears to be associated with mortality through a number of independent mechanisms, perhaps through complex feedback loops.

Toward a threshold for subthreshold depression: an analysis of correlates of depression by severity of symptoms using data from an elderly community sample.

PURPOSE: The prevalence of depressive symptoms in elderly adults is high, yet the criteria to identify clinically significant depression may leave many elders undiagnosed and untreated. We explored the demographic and risk factor profiles of two groups, one with more severe depression and one with less severe depression. DESIGN AND METHODS: The data come from the Duke University Established Populations for Epidemiologic Studies of the Elderly (EPESE) baseline survey of 4,162 community-dwelling adults aged 65 or older. RESULTS: The prevalence of depression meeting criteria of the Center for Epidemiologic Studies-Depression scale (CES-D) and sub-threshold depression was 9.1% and 9.9%, respectively. In ordinal logistic regression, both CES-D and subthreshold depression were associated with impairment in physical functioning, disability days, poorer self-rated health, use of psychotropic medications, perceived low social support, female gender, and being unmarried. IMPLICATIONS: Depression appears to exist along a continuum, with demographic and social and physical health predictors of subthreshold depression similar to predictors of depression as defined by the CES-D scale.

Social and personal resources and the prevalence of phobic disorder in a community population.

BACKGROUND: Phobic disorder is one of the most prevalent psychiatric disorders in community populations and much attention has focused on the association of sociodemographic factors and social resources with the disorder. There has been little investigation of the more personal resources such as self-confidence, religiosity, social support and self-perceived health that may increase vulnerability. METHODS: We used a sample of 2914 community residents aged 18 or older who participated in the Duke University Epidemiologic Catchment Area Study to explore the relationship between both social and personal resources and the prevalence of DIS/DSM-III phobic disorder. RESULTS: The 1-month prevalence of any phobic disorder was 7.6%. In bivariate analyses, we found both race/ethnicity and gender differences in prevalence, with a higher prevalence of phobic disorder in African-Americans and females. Lower socio-economic status, rural residence and unmarried status were also associated with current prevalence. No association was found for social network and social interaction. Impaired subjective social support, low self-confidence, perceived poorer physical health and co-morbid psychiatric disorder were significantly associated with current prevalence in uncontrolled analyses, while associations between lack of a confidant as well as religiosity and phobic disorder were not. Female gender (OR = 1.7), perceived low self-confidence (OR = 2.0), and two interaction terms, age x co-morbid psychiatric disorder and race/ethnicity x perceived physical health were associated with phobic disorder in controlled analyses using logistic regression. CONCLUSIONS: We conclude that both social and personal resources, particularly self-confidence, co-morbidity and perceived physical health are important correlates of phobic disorder.