Elder abuse and mortality: the role of psychological and social wellbeing.

BACKGROUND: Elder abuse is a pervasive human right and public health issue. OBJECTIVES: We aimed to examine the mortality associated with elder abuse across levels of psychological and social factors. METHODS: The Chicago Health and Aging Project (CHAP) is a prospective population-based cohort study that began in 1993. A subset of these participants enrolled between 1993 and 2005 had elder abuse reported to social services agencies (n = 113). Mortality was ascertained during follow-up and with the National Death Index. Psychosocial factors (depression, social network and social engagement) were assessed during the CHAP interview. Cox proportional hazard models were used to assess the mortality of elder abuse across levels of psychosocial factors using time-varying covariate analyses. RESULTS: The median follow-up time for the cohort (n = 7,841) was 7.6 years (interquartile range 3.8-12.4 years). In multivariate analyses, those with highest (hazard ratio (HR) 2.60, 95% CI 1.58-4.28) and middle levels (HR 2.18, 95% CI 1.19-3.99) of depressive symptoms had an increased mortality risk associated with elder abuse. For social network, those with lowest (HR 2.50, 95% CI 1.62-3.87) and middle levels (HR 2.65, 95% CI 1.52-4.60) of social network had increased mortality risk associated with elder abuse. For social engagement, those with lowest (HR 2.32, 95% CI 1.47-3.68) and middle levels (HR 2.59, 95% CI 1.65-5.45) of social engagement had increased mortality risk associated with elder abuse. Among those with lowest levels of depressive symptoms, highest levels of social network and social engagement, there was no significant effect of reported or confirmed elder abuse on mortality risk. CONCLUSION: Mortality risk associated with elder abuse was most prominent among those with higher levels of depressive symptoms and lower levels of social network and social engagement.

Cognitive activity and the cognitive morbidity of Alzheimer disease.

OBJECTIVE: To test the hypothesis that frequent cognitive activity predicts slower cognitive decline before dementia onset in Alzheimer disease (AD) and faster decline thereafter. METHODS: As part of a longitudinal cohort study, older residents of a geographically defined population were assessed at 3-year intervals with brief cognitive performance tests from which a composite measure of global cognition was derived. After each wave of testing, a subset was sampled for clinical evaluation. The present analyses are based on 1,157 participants. They were free of dementia at study enrollment at which time they rated frequency of participation in common cognitively stimulating activities from which a previously validated summary measure was derived. They were sampled for clinical evaluation a mean of 5.6 years after enrollment and subsequently followed a mean of 5.7 years with brief cognitive performance testing at 3-year intervals. RESULTS: On clinical evaluation, 614 people had no cognitive impairment, 395 had mild cognitive impairment, and 148 had AD. During follow-up, the annual rate of global cognitive decline in persons without cognitive impairment was reduced by 52% (estimate = 0.029, SE = 0.010, p = 0.003) for each additional point on the cognitive activity scale. In the mild cognitive impairment group, cognitive decline rate was unrelated to cognitive activity (estimate = -0.019, SE = 0.018, p = 0.300). In AD, the mean rate of decline per year increased by 42% (estimate = 0.075, SE = 0.021, p < 0.001) for each point on the cognitive activity scale. CONCLUSION: Mentally stimulating activity in old age appears to compress the cognitive morbidity associated with AD by slowing cognitive decline before dementia onset and hastening it thereafter.

Temporal course of depressive symptoms during the development of Alzheimer disease.

OBJECTIVE: To characterize change in depressive symptoms before and after the onset of dementia in Alzheimer disease (AD). METHOD: We used data from the Chicago Health and Aging Project, a longitudinal cohort study of risk factors for AD in a geographically defined population of old people. Two subsets were analyzed. In 357 individuals who developed incident AD during the study, self-report of depressive symptoms (Center for Epidemiologic Studies Depression Scale) was obtained at 3-year intervals for a mean of 8 to 9 years. In 340 individuals who agreed to annual data collection, informant report of depressive symptoms (Hamilton Depression Rating Scale) was obtained for a mean of 3 years after a diagnosis of AD (n = 107), mild cognitive impairment (n = 81), or no cognitive impairment (n = 152). RESULTS: The incident AD group reported a barely perceptible increase in depressive symptoms during 6 to 7 years of observation before the diagnosis (0.04 symptoms per year) and no change during 2 to 3 years of observation after the diagnosis except for a slight decrease in positive affect. In those with annual follow-up, neither AD nor its precursor, mild cognitive impairment, was associated with change in informant report of depressive symptoms during a mean of 3 years of observation. CONCLUSION: Depressive symptoms show little change during the development and progression of AD to a moderate level of dementia severity.

Cognitive decline in incident Alzheimer disease in a community population.

OBJECTIVE: To measure the cognitive consequences of incident Alzheimer disease (AD) in older African American and white subjects. METHODS: Data are from the Chicago Health and Aging Project, a longitudinal cohort study of older white and black persons residing in a geographically defined community. At 3-year intervals, the entire study population completed 4 brief cognitive tests, from which a previously established composite measure of global cognition was derived, and a subset underwent detailed clinical evaluation that supported clinical classification of mild cognitive impairment, dementia, and AD. We used mixed-effects models to examine change in cognitive function following the diagnostic evaluation. RESULTS: On clinical evaluation, 614 persons were found to have no cognitive impairment, 395 had mild cognitive impairment, and 149 had AD (88.5% mild); 10 persons with other dementias were excluded from analyses. During up to 11 years of observation following the clinical evaluation (mean = 5.5, SD = 2.5), the composite measure of global cognition declined a mean of 0.042 unit per year (SE = 0.008, p < 0.001) in those with no cognitive impairment. In comparison to the no cognitive impairment group, the annual rate of decline was increased more than twofold in mild cognitive impairment (estimate = 0.086, SE = 0.011, p < 0.001) and more than fourfold in AD (estimate = 0.173, SE = 0.020, p < 0.001). Results did not reliably vary by race, sex, or age. CONCLUSIONS: Alzheimer disease has a devastating impact on cognition, even in its prodromal stages, with comparable effects in African American and white persons.

Educational attainment and cognitive decline in old age.

BACKGROUND: Level of education is a well-established risk factor for Alzheimer disease but its relation to cognitive decline, the principal clinical manifestation of the disease, is uncertain. METHODS: More than 6,000 older residents of a community on the south side of Chicago were interviewed at approximately 3-year intervals for up to 14 years. The interview included administration of four brief tests of cognitive function from which a previously established composite measure of global cognition was derived. We estimated the associations of education with baseline level of cognition and rate of cognitive change in a series of mixed-effects models. RESULTS: In an initial analysis, higher level of education was related to higher level of cognition at baseline, but there was no linear association between education and rate of change in cognitive function. In a subsequent analysis with terms to allow for nonlinearity in education and its relation to cognitive decline, rate of cognitive decline at average or high levels of education was slightly increased during earlier years of follow-up but slightly decreased in later years in comparison to low levels of education. Findings were similar among black and white participants. Cognitive performance improved with repeated test administration, but there was no evidence that retest effects were related to education or attenuated education's association with cognitive change. CONCLUSIONS: The results suggest that education is robustly associated with level of cognitive function but not with rate of cognitive decline and that the former association primarily accounts for education's correlation with risk of dementia in old age.

Socioeconomic characteristics of the community in childhood and cognition in old age.

We examined the relation of early life socioeconomic circumstances to cognition in older residents of a biracial urban community. Participants had brief cognitive testing three times at approximately 3-year intervals. At baseline, information about early life household and county socioeconomic level was collected. In mixed-effects models adjusted for age, sex, race, and education, both early life household and county socioeconomic levels were positively associated with baseline level of cognition but unrelated to cognitive decline. The results suggest that socioeconomic conditions in early life are associated with level of cognitive function in old age but not with rate of cognitive decline.

Proneness to psychological distress and risk of Alzheimer disease in a biracial community.

Persons without dementia residing in a biracial community completed a brief scale of proneness to psychological distress, and 1,064 were subsequently examined for incident Alzheimer disease (AD) 3 to 6 years later. In analyses controlling for selected demographic and clinical variables, persons prone to distress were 2.4 times more likely to develop AD than persons not distress prone. This effect was substantially stronger in white persons compared to African Americans.

Social resources and cognitive decline in a population of older African Americans and whites.

OBJECTIVE: To examine the relation of social resources and cognitive decline in older adults. METHODS: Data are from the Chicago Health and Aging Project, an epidemiologic study of risk factors for Alzheimer disease (AD) and other common conditions in a geographically defined population of older persons. The sample consisted of 6,102 non-Hispanic African Americans (61.2%) and whites, aged > or = 65, who underwent up to three interviews during an average of 5.3 years of follow-up. Each interview included administration of four cognitive function tests from which a composite measure of cognition was formed. Social networks were based on the number of children, relatives, and friends seen at least once a month. Social engagement was measured with four items related to social and productive activity. RESULTS: Higher number of social networks and level of social engagement were positively correlated with initial level of cognitive function (networks estimate = 0.003, engagement estimate = 0.060, both p < 0.001). Both resources were also associated with a reduced rate of cognitive decline. A high (90th percentile) number of networks reduced the rate of decline by 39% compared to a low level (10th percentile), and high social engagement reduced decline by 91%. These relations remained after controlling for socioeconomic status, cognitive activity, physical activity, depressive symptoms, and chronic medical conditions. CONCLUSIONS: Greater social resources, as defined by social networks and social engagement, are associated with reduced cognitive decline in old age.

Depressive symptoms and cognitive decline in a community population of older persons.

BACKGROUND: An association between depressive symptoms and cognitive decline has been observed in selected cohorts of older people, but studies of defined populations have had conflicting results. OBJECTIVE: To test whether the level of depressive symptoms predicted the rate of cognitive decline in a biracial community of older persons. METHODS: 4392 older people (88% of those eligible) from a defined community in Chicago completed two or three structured interviews at approximately three year intervals for an average of 5.3 years. At the baseline interview, the number of depressive symptoms was assessed with a 10 item version of the Center for Epidemiologic Studies Depression scale. Cognitive function was assessed at each interview with four performance tests, from which a previously established measure of global cognition was derived. Random effects models were used to assess change in cognition and its relation to depressive symptoms, controlling for age, sex, race, education, and baseline cognitive function. RESULTS: Participants reported a median of one depressive symptom at baseline (interquartile range, 0 to 2). For each depressive symptom, the rate of cognitive decline increased by a mean of about 5%. Results were not substantially changed when persons with cognitive impairment at baseline were excluded, or when chronic illness or participation in cognitively stimulating activities was controlled, and the association was not modified by age, sex, race, or education. CONCLUSIONS: The results suggest that depressive symptoms predict cognitive decline in old age.

Proneness to psychological distress is associated with risk of Alzheimer's disease.

BACKGROUND: Chronic stress is associated with hippocampal damage and impaired memory in animals and humans. OBJECTIVE: To examine this relationship with clinical and pathologic data from the Religious Orders Study. METHODS: Older Catholic clergy members underwent annual clinical evaluations, which included clinical classification of Alzheimer's disease (AD) and detailed cognitive function testing from which composite measures of global cognition and specific cognitive functions were derived. At the baseline evaluation, participants completed a measure of the tendency to experience psychological distress, a stable personality trait that served as an indicator of susceptibility to negative emotional states across the life span. More than 90% of participants who died underwent a uniform postmortem examination of the brain from which summary measures of AD pathology were derived. The association of distress proneness with incident AD and cognitive decline and with measures of AD pathology was examined in analyses adjusted for selected demographic and clinical variables. RESULTS: During a mean of 4.9 years of follow-up, 140 persons developed AD. Those high in distress proneness (90th percentile) had twice the risk of developing AD than those low in distress proneness (10th percentile). Distress proneness was related to decline in episodic memory but not in other cognitive domains, with a >10-fold increase in episodic memory decline in those high in distress proneness compared with those low in the trait. Among those who died, however, distress proneness was not related to common measures of AD pathology. CONCLUSION: Proneness to experience psychological distress is a risk factor for AD, an effect independent of AD pathologic markers such as cortical plaques and tangles.

Cognitive activity and cognitive decline in a biracial community population.

BACKGROUND: Frequent participation in cognitively stimulating activities has been associated with reduced risk of AD in several prospective studies. However, the association of cognitive activity with cognitive decline, the principal manifestation of AD, is not well understood. METHODS: More than 4,000 older residents of a geographically defined biracial community of Chicago were interviewed at approximately 3-year intervals for an average of 5.3 years. Each interview included administration of four cognitive function tests from which a previously established global measure was derived. At baseline, each person rated frequency of participation in cognitively stimulating activities (e.g., reading a magazine) from which a previously established composite measure of cognitive activity was derived. RESULTS: Cognitive activity scores ranged from 1 to 5 (mean = 3.14, SD = 0.66), with higher scores indicating more frequent participation. More frequent cognitive activity was associated with reduced cognitive decline during follow-up. In a model that controlled for baseline level of cognition, age, sex, race, and education, a 1-point increase in cognitive activity score was associated with an approximately 19% decrease in annual rate of cognitive decline (p < 0.001). This effect remained when we controlled for depressive symptoms and chronic medical conditions (p < 0.001), and when we excluded persons with evidence of memory impairment at baseline (p < 0.001). CONCLUSION: Frequent participation in cognitively stimulating activities is associated with reduced cognitive decline in older persons.

Education modifies the relation of AD pathology to level of cognitive function in older persons.

OBJECTIVE: To test the hypothesis that years of formal education modifies the relation of AD pathology to level of cognitive function. METHODS: A total of 130 older Catholic clergy participating in the Religious Orders Study underwent annual cognitive function testing and brain autopsy at the time of death. Individual cognitive function tests were z-scored and averaged to yield a global measure of cognitive function and summary measures of five different cognitive abilities. Neuritic and diffuse plaques and neurofibrillary tangles were counted in separate 1 mm(2) areas of maximal density. Counts were converted to standard scores by dividing by their SD, and combined to yield a global AD pathology score and summary scores of each postmortem index. Linear regression was used to examine the relation of education and AD pathology scores to level of cognitive function proximate to death, controlling for age and sex. Subsequent analyses tested the interaction between education and each AD pathology score to determine whether education modified the relation of AD pathology to level of cognitive function. Additional analyses examined these associations on five specific cognitive abilities. RESULTS: Both years of formal education (regression coefficient = 0.073, p = 0.0001) and the global AD pathology score (regression coefficient = -0.689, p < 0.0001) were related to level of cognitive function. When an interaction term between education and AD pathology was added to the model, the association between a unit of AD pathology and level of cognitive function was 0.088 (p = 0.0078) standard unit less for each year of education than the level predicted from the model without the interaction term. Whereas neuritic plaques, diffuse plaques, and neurofibrillary tangles were all strongly related to cognitive function, education only modified the relation of neuritic plaques (p = 0.002) and diffuse plaques (p = 0.03) to cognition, but not neurofibrillary tangles. In analyses examining five different cognitive abilities, the interaction between education and the neuritic plaque score was strongest for perceptual speed and weakest for episodic memory. CONCLUSIONS: These data provide strong evidence that the relation between senile plaques and level of cognitive function differs by years of formal education.

Cognitive activity and incident AD in a population-based sample of older persons.

BACKGROUND: Participation in cognitively stimulating activities is hypothesized to be associated with risk of AD, but knowledge about this association is limited. METHODS: A biracial community in Chicago was censused, persons aged 65 years and older were asked to participate in an interview, and 6,158 of 7,826 (79%) eligible persons did so. As part of the interview, persons rated current frequency of participation in seven cognitive activities (e.g., reading a newspaper) and nine physical activities (e.g., walking for exercise) from which composite measures of cognitive and physical activity frequency were derived. Four years later, 1,249 of those judged free of AD were sampled for a detailed clinical evaluation of incident disease and 842 (74% of those eligible) participated. RESULTS: The composite measure of cognitive activity ranged from 1.28 to 4.71 (mean 3.30; SD 0.59), with higher scores indicating more frequent activity. A total of 139 persons met National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for AD on clinical evaluation. In a logistic regression model adjusted for age, education, sex, race, and possession of the APOE epsilon4 allele, a one-point increase in cognitive activity score was associated with a 64% reduction in risk of incident AD (OR 0.36; 95% CI 0.20 to 0.65). By contrast, weekly hours of physical activity (mean 3.5; SD 5.1) was not related to disease risk (OR 1.04; 95% CI 0.98 to 1.10). Education was associated with risk of AD and a similar trend was present for occupation, but these effects were substantially reduced when cognitive activity was added to the model. CONCLUSION: Frequency of participation in cognitively stimulating activities appears to be associated with risk of AD and may partially explain the association of educational and occupational attainment with disease risk.

Depressive symptoms, cognitive decline, and risk of AD in older persons.

BACKGROUND: Cross-sectional and retrospective case-control studies suggest an association of depression symptoms with cognitive impairment and AD, but there have been few prospective studies and their results have been inconsistent. METHODS: Participants are Catholic clergy members who were aged > or =65 years and who did not have clinical evidence of AD. During a 7-year period, they underwent annual clinical evaluations that included clinical classification of AD and detailed cognitive function testing from which global and specific measures of cognition were derived. Number of depressive symptoms was assessed at baseline with a modified, 10-item Center for Epidemiologic Studies Depression Scale (CES-D). The association of CES-D score with incident AD, using proportional hazards models, and cognitive decline, using random effects models, was examined. RESULTS: At baseline, participants reported an average of about one depressive symptom on the CES-D scale (range, 0 to 8). During the 7 years of follow-up, 108 persons developed AD. In analyses that controlled for selected demographic and clinical variables including baseline level of cognitive function, CES-D score was associated with both risk of AD and rate of cognitive decline. For each depressive symptom, risk of developing AD increased by an average of 19%, and annual decline on a global cognitive measure increased by an average of 24%. CONCLUSIONS: The results raise the possibility that depressive symptoms in older persons may be associated with risk of developing AD.

Disability as a function of social networks and support in elderly African Americans and Whites: the Duke EPESE 1986--1992.

OBJECTIVES: We examined the association of structural and functional aspects of social relationships with change in disability, and the degree to which race modifies these associations. METHODS: Data are from a population-based sample of 4,136 African Americans and Whites aged > or = 65 living in North CAROLINA: Disability data were collected during seven consecutive yearly interviews and summarized in two outcome measures. Measures of social relationships included five measures representing network size, extent of social interaction, and specific type of relationships, as well as instrumental and emotional support. Weighted proportional odds models were fitted to model disability as a function of baseline social network and support variables, and the interaction of each variable with follow-up time. RESULTS: Network size and social interaction showed significant negative associations with disability risks, which did not vary by race, or as a function of time. Social interaction with friends was associated with a reduced risk for disability, but social interaction with children or relatives was not related to disability. Instrumental support was associated with a significantly increased disability risk, with a greater adverse effect among Whites than African AMERICANS: Emotional support was not associated with disability, but a protective effect for ADL disability was found after controlling for its intercorrelation with instrumental support. DISCUSSION: The findings provide further evidence for the role of social relationships in the disablement process, although not all types of social relationships may be equally beneficial. Furthermore, these associations may be more complex than simple causal effects. There were few racial differences in the association of social relationships with disability, with the possible exception of instrumental support, which may allude to possible sociocultural differences in the experience of instrumental support exchanges.

Psychosocial characteristics after acute myocardial infarction: the ENRICHD pilot study. Enhancing Recovery in Coronary Heart Disease.

PURPOSE: Psychosocial factors, such as emotional distress and social isolation, have been increasingly recognized as important risk factors for patients' recovery from acute myocardial infarction (AMI). This study examined age, gender, and ethnic differences in depression and general distress, social support, and health-related quality of life after AMI. METHODS: Data came from a series of 88 patients aged 62.1 +/- 14.2 years (46% female) who were hospitalized for AMI at eight different US clinical centers participating in the Enhancing Recovery in Coronary Heart Disease (ENRICHD) Pilot Study. Standardized psychometric measures were administered to assess three psychosocial domains: (1) depression and general distress (mental health functioning), (2) social support, and (3) health-related quality of life. Multivariate analysis of variance was used to examine the effects of age, gender, and ethnic differences in each of the three psychosocial domains. RESULTS: Female patients reported higher levels of depression and distress compared with male patients (P = .040). Gender differences in mental health functioning differed by age (P = .046), with the greatest differences observed among younger female patients. Older patients (P = .014) and female patients (P = .025) reported lower levels of social support compared with younger and male patients, respectively. Minority patients did not differ from nonminority patients in mental health functioning or social support, and there were no significant differences in post-AMI quality of life on the basis of age, gender, or ethnicity. CONCLUSIONS: The psychosocial risk profile after AMI may be different for male and female patients, and interventions may need to take account of each gender's specific needs.

The prevalence of dizziness and its association with functional disability in a biracial community population.

BACKGROUND: Information regarding the prevalence of dizziness and its association with functional disability among African American and white residents from defined community populations is limited. METHODS: A total of 6,158 persons 65 years and older (78.8% of age-eligible persons) completed in-home interviews that included three common measures of self-reported disability: the Katz Activities of Daily Living (ADL) Scale, the Rosow-Breslau Functional Health Scale, and the Nagi Physical Disability Scale. A stratified random sample of 729 persons underwent a detailed evaluation that included questions on the frequency and severity of dizziness, which was defined as having an episode of dizziness or lightheadedness at least once a month. RESULTS: The overall prevalence of dizziness in this population was 9.6% (95% confidence interval [CI] 7.2-12.0). It increased with age, from 6.6% in those 65-74 years old, to 11.6% in those 75-84 years old, and to 18.4% in those persons > or =85 years old. It was more common in women (odds ratio [OR] 2.03, 95% CI 0.99-4.19) but was not associated with race. After adjusting for age, sex, and race, dizziness was associated with greater disability on the Rosow-Breslau (OR 2.29, 95% CI 1.18-4.46) and Nagi (OR 2.54, 95% CI 1.48-4.36) measures but not on the Katz ADL Scale (OR 1.18, 95% CI 0.64-2.20). CONCLUSIONS: Dizziness is common among older persons and is associated with functional disability.

Social networks and disability transitions across eight intervals of yearly data in the New Haven EPESE.

OBJECTIVES: There is considerable evidence that social networks are strongly related to survival and other health outcomes. However, findings regarding the effect of social networks on disability outcomes have been inconsistent. This study examines this relationship with respect to the risk of developing disability and recovering from disability. METHODS: Data come from a community-based sample of the New Haven population aged 65 years and older, with nine annual interviews conducted between 1982 and 1991. Disability was measured by a 6-item index of activities of daily living (ADL), and a 3-item Rosow-Breslau index, with disability defined as impairment in one or more tasks on each measure. Social network variables were constructed for each of four domains of ties: children, relatives, friends, and a confidant, and a summary measure of total social networks. A Markov model was used to estimate one-year disability transitions averaged across all 8 intervals, after controlling for sociodemographic and health-related variables. RESULTS: Total social networks was associated with a significantly reduced risk of developing ADL disability (beta = -0.009, p < .01), and a significantly increased likelihood of ADL recovery (beta = 0.017, p < .01). Emotional and instrumental support did not affect the protective effect of social networks against disability, but partially accounted for their effect on enhanced recovery. Network variables related to relatives and friends were significantly associated with disability and recovery risks, but those related to children or a confidant were not. The associations with disability transitions as measured by the Rosow-Breslau index were generally smaller and nonsignificant. DISCUSSION: The findings lend further support for the role of social relationships in important health outcomes in old age. They suggest that being "embedded" in a social network of relatives and friends reduces risk for ADL disability, and enhances recovery from ADL disability.

Self-efficacy beliefs and perceived declines in functional ability: MacArthur studies of successful aging.

Longitudinal data from a cohort of older men and women, aged 70-79, were used to test the hypothesis that stronger self-efficacy beliefs would protect against onset of perceived functional disabilities over a 2.5-year follow-up, independent of underlying physical ability. Standard self-report scales were used to assess perceived functional disabilities, ranging from mild performance difficulties (measured by a 5-item scale based on items by Nagi) to more severe disabilities (measured by the 7-item Katz Activities of Daily Living Scale [ADL]). Performance-based measurements of strength, balance, and gait provide more objective assessments of physical abilities. Self-efficacy beliefs were measured in terms of beliefs relating to managing interpersonal relationships and beliefs relating to managing more instrumental daily activities. Gender-specific multiple regression models revealed that weaker instrumental self-efficacy beliefs predicted declines in reported functional status as measured by the Nagi performance scale among both men and women, independent of standard sociodemographic, health status, and health behaviors. Among men, instrumental efficacy beliefs were also negatively related to reports of onset of Katz ADL. Self-efficacy beliefs were unrelated to measured changes in actual physical performance abilities for both men and women. These findings suggest that self-efficacy beliefs have significant impacts on perceptions of functional disability, independent of actual underlying physical abilities. Through such influences on perceptions of disability, self-efficacy beliefs may importantly affect lifestyles and quality of life at older ages.