Biomedical subjects

Laura E Gibbons

Publications and source records attributed to Laura E Gibbons.

At least 19 recordsLinked to original sources

PubMed2006

Rapid detection of differential item functioning in assessments of health-related quality of life: The Functional Assessment of Cancer Therapy.

REASON FOR STUDY: Differential item functioning (DIF) occurs when a test item functions differently in different groups when controlling for the level of the underlying construct measured by the test. DIF assessment is a first step in the evaluation of test bias. We sought to demonstrate a rapid hybrid approach to DIF detection by determining the presence and scale-level impact of DIF related to eight covariates in four domains measured by the Functional Assessment of Cancer Therapy (FACT). MAJOR FINDINGS: The number of items found with DIF in each domain depended on the criterion chosen to define the presence of DIF. With a few exceptions, scale-level differential functioning was similar regardless of the criteria chosen. For physical well-being, there was relevant scale-level differential functioning related only to race. For social and family well-being, there was relevant scale-level differential functioning related to each of the covariates. For emotional well-being, there was relevant scale-level differential functioning related to ethnicity, language, and race. For functional well-being, there was relevant scale-level differential functioning related to ethnicity, race, education, and self- vs. interviewer-administration. PRINCIPAL CONCLUSIONS: Our rapid hybrid approach to DIF detection may be broadly applicable in other studies of health-related quality of life.

Adolescent↗

PubMed2006

A 37-item shoulder functional status item pool had negligible differential item functioning.

OBJECTIVE: Measures of shoulder function may differ by dominance of affected shoulder, surgical history, gender, or race. We present a technique for determining whether observed differences in function between groups are due to biased test items or real differences in function. STUDY DESIGN AND SETTING: Four hundred patients who were receiving rehabilitation for a variety of shoulder impairments completed a survey of shoulder function. Thirty-seven items measuring shoulder function were analyzed for differential item functioning (DIF) related to demographic characteristics using an ordinal logistic regression (OLR) and item response theory (IRT) approach. When DIF was identified in an item, we modified the IRT analysis to calibrate item parameters separately in appropriate demographic groups. We compared adjusted and unadjusted patient ability measures in each demographic group. RESULTS: Several items were found to have a modest amount of DIF related to the different demographic characteristics, especially gender; however, adjusting measures for DIF had little impact on overall measures of shoulder function and made almost no difference in average shoulder function across demographic groups. CONCLUSION: In this pool of shoulder function items, adjustment for DIF made almost no difference in measures of function across demographic groups.

Activities of Daily Living↗

PubMed2006

Differential item functioning related to education and age in the Italian version of the Mini-mental State Examination.

BACKGROUND: Differential item functioning (DIF) exists when test item responses by members of different demographic groups are statistically different when controlling for ability. DIF may indicate item bias. Our objective was to determine whether items from the Italian Mini-mental State Examination (MMSE) had DIF related to educational attainment, age, gender and occupation. We were also interested in exploring the significance of DIF in screening tests. METHODS: In a two-stage study from Granarolo, Italy, residents over age 61 (n = 495) were evaluated with the Italian MMSE. Those with MMSE scores of 28 or lower were further evaluated for dementia. MMSE results were coded in 10 item bundles. We used ordinal logistic regression to determine whether item bundles had DIF. RESULTS: Six of the 10 MMSE item bundles had DIF in educational attainment subgroups. Four of these six bundles also had DIF related to age. Items that required literacy were much harder for those with lower educational attainment. CONCLUSIONS: DIF related to education appeared at as few as 3 years of formal schooling. These findings suggest cautious interpretation of data from studies using the Italian MMSE in populations with heterogeneous educational backgrounds. DIF is especially troublesome for two-stage studies that use screening tests.

Aged↗

PubMed2006

Factors associated with caregiver reports of sleep disturbances in persons with dementia.

OBJECTIVE: This investigation examined the relationship between caregivers' reports of sleep disturbances in persons with Alzheimer disease (AD) and actigraphic records of patients' sleep-wake activity, and explored the factors associated with discrepancies in this relationship. METHOD: Forty-six patients with AD living with their caregivers participated. Before study entry, all caregivers reported poor patient sleep quality using the Neuropsychiatric Inventory (NPI) Nighttime Behavior Scale. Patient sleep-wake activity was recorded for one week using an Actillume wrist-movement recorder. RESULTS: Although all patients were reported by caregivers to have multiple sleep disturbances, 41% of patients had actigraphic sleep efficiencies in the normal range and 43% averaged eight or more hours of sleep nightly. In bivariate analyses, greater patient percent nighttime sleep (indicative of more discrepancy between subjective reports and objective outcomes) was associated with less patient cognitive, physical and functional impairment, lower self-rated depression, higher self-rated quality of life, and less daytime sleepiness. No patient variable significantly predicted total patient nocturnal sleep time. In both bivariate and multivariate analyses, greater patient percent sleep and total sleep time were also associated with caregiver factors, particularly greater use of criticism as a behavior management strategy. CONCLUSION: The study suggests that both patient and caregiver factors contribute to reported sleep problems in community-dwelling patients with AD, and that caregiver reports and objective sleep assessments frequently may not agree. Treatments should consider these dyadic contributions rather than focusing on caregiver reports of patient symptoms alone.

Adult↗

PubMed2006

Differential item functioning analysis with ordinal logistic regression techniques. DIFdetect and difwithpar.

INTRODUCTION: We present an ordinal logistic regression model for identification of items with differential item functioning (DIF) and apply this model to a Mini-Mental State Examination (MMSE) dataset. We employ item response theory ability estimation in our models. Three nested ordinal logistic regression models are applied to each item. Model testing begins with examination of the statistical significance of the interaction term between ability and the group indicator, consistent with nonuniform DIF. Then we turn our attention to the coefficient of the ability term in models with and without the group term. If including the group term has a marked effect on that coefficient, we declare that it has uniform DIF. We examined DIF related to language of test administration in addition to self-reported race, Hispanic ethnicity, age, years of education, and sex. METHODS: We used PARSCALE for IRT analyses and STATA for ordinal logistic regression approaches. We used an iterative technique for adjusting IRT ability estimates on the basis of DIF findings. RESULTS: Five items were found to have DIF related to language. These same items also had DIF related to other covariates. DISCUSSION: The ordinal logistic regression approach to DIF detection, when combined with IRT ability estimates, provides a reasonable alternative for DIF detection. There appear to be several items with significant DIF related to language of test administration in the MMSE. More attention needs to be paid to the specific criteria used to determine whether an item has DIF, not just the technique used to identify DIF.

Bias↗

PubMed2006

Assessment of anxiety in dementia: an investigation into the association of different methods of measurement.

The objectives were to compare patient and caregiver ratings of anxiety for individuals with Alzheimer's disease and investigate their association with ratings of patient depression. Participants were 95 community-dwelling Alzheimer's disease patients and their caregivers. Measurements included caregiver proxy ratings: Rating Anxiety in Dementia, the NeuroPsychiatric Inventory, the Revised Memory and Behavior Problems Checklist, and the Cornell Scale for Depression in Dementia. Patient self-assessments included the Clinical Anxiety Scale (adapted) and the Geriatric Depression Scale. Correlations among anxiety measures ranged from rho = .16 to .40, whereas correlations between anxiety and depression scales ranged from rho = .03 to .66. Overlap among items across both anxiety and depression scales appeared to be the most important factor in determining these associations. Current scales for anxiety in dementia differ in their construction of symptoms and can overlap considerably with depression scales. Because of this, measures inadequately distinguish anxiety from depression in individuals with Alzheimer's disease. The measurement of anxiety in dementia needs additional refinement.

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PubMed2005

Fatigue and psychiatric illness in a large community sample of persons with multiple sclerosis.

BACKGROUND: Fatigue and depression are among the most common and disabling symptoms in multiple sclerosis (MS), but the nature and extent of the relationships between fatigue and psychiatric disorders in MS patients remain poorly understood. METHODS: A mail survey was completed by 739 members of the King County (WA) MS Association. Fatigue was evaluated by questions from the Modified Fatigue Impact Scale (MFIS), depressive symptoms by the Center for Epidemiologic Studies Depression Scale (CES-D), substance-use disorders from the PRIME-MD. Information on demographics, employment and characteristics of MS was also collected. Logistic regression was used to identify covariates significantly associated with disabling fatigue. Receiver operating characteristic (ROC) curve analysis evaluated the sensitivity and specificity of fatigue for depression. RESULTS: Twenty-five percent of this community-dwelling sample reported that their activities were often or almost always limited by fatigue. Seventy-six percent of subjects with disabling fatigue had significant depressive symptoms (CES-D >16), compared with 31% of those without disabling fatigue. Depression was strongly associated with fatigue, after controlling for age, gender, marital status, and severity, course and duration of illness. In logistic regression analysis, subjects with clinically significant depressive symptoms (CES-D >16) were much more likely to report disabling fatigue: OR = 6.24 (4.16, 9.35). Anxiety and substance-use disorders did not have the same strong associations with fatigue. Fatigue was highly sensitive and specific for clinically significant depressive symptoms. CONCLUSIONS: Disabling fatigue is strongly associated with clinically significant depressive symptoms. Patients who report disabling fatigue should be screened for depression.

Adult↗

PubMed2005

Training community consultants to help family members improve dementia care: a randomized controlled trial.

PURPOSE: We investigated whether community consultants could be trained to teach family caregivers a systematic behavioral approach for reducing mood and behavior problems in persons with Alzheimer's disease. DESIGN AND METHODS: This study consisted of a randomized controlled trial; we randomly assigned 95 family caregivers and care recipients with Alzheimer's disease to STAR-caregivers (STAR-C) or control groups. Masked interviewers conducted assessments at baseline, after treatment, and after 6 months. Consultants were master's-level health care professionals who were currently practicing in community settings serving older adults. We assessed the extent to which consultants were able to learn and adhere to the treatment protocol, and the relationship between adherence and measures of caregiver mood, burden, and care recipient mood and behavior. RESULTS: Community consultants were able to learn and adhere to the behavioral treatment protocol. Caregivers receiving STAR-C training showed significant improvements in depression, burden, and reactivity to behavior problems in the care recipient. There were also significant reductions in the frequency and severity of care recipient behavior problems, and improved quality of life. Results were maintained at 6-month follow-up. IMPLICATIONS: Community-based consultants successfully implemented a behavioral intervention with family caregivers of persons with Alzheimer's disease. Consequently, STAR-C seems to be a practicable and reasonable evidenced-based approach to caregiver training in actual clinical settings.

Aged↗

PubMed2005

Nighttime insomnia treatment and education for Alzheimer's disease: a randomized, controlled trial.

OBJECTIVES: To evaluate whether a comprehensive sleep education program (Nighttime Insomnia Treatment and Education for Alzheimer's Disease (NITE-AD)) could improve sleep in dementia patients living at home with their family caregivers. DESIGN: A randomized, controlled trial. PARTICIPANTS: Thirty-six community-dwelling patients with Alzheimer's disease (AD) and their family caregivers. INTERVENTION: All participants received written materials describing age- and dementia-related changes in sleep and standard principles of good sleep hygiene. Caregivers in active treatment (n=17) received specific recommendations about setting up and implementing a sleep hygiene program for the dementia patient and training in behavior management skills. Patients in active treatment were also instructed to walk daily and increase daytime light exposure with the use of a light box. Control subjects (n=19) received general dementia education and caregiver support. MEASUREMENTS: Primary sleep outcomes were derived for patients and caregivers from 1 week of sleep-wake activity measured at baseline, posttest (2 months), and 6-month follow-up using an Actillume wrist-movement recorder. Secondary patient outcomes included the Epworth Sleepiness Scale, the Cornell Depression Scale, and the Revised Memory and Behavior Problem Checklist. Caregiver self-reports included the Pittsburgh Sleep Quality Index and the Center for Epidemiological Study of Depression Scale. RESULTS: Patients participating in NITE-AD showed significantly greater (P<.05) posttest reductions in number of nighttime awakenings, total time awake at night, and depression, and increases in weekly exercise days than control subjects. At 6-month follow-up, treatment gains were maintained, and additional significant improvements in duration of night awakenings emerged. When cognitive level was controlled, NITE-AD patients had lower longitudinal ratings of daytime sleepiness than controls. There was a trend for control subjects to spend more time in bed at 6 months than NITE-AD patients. CONCLUSION: This study provides the first evidence that patients with AD who are experiencing sleep problems can benefit from behavioral techniques (specifically, sleep hygiene education, daily walking, and increased light exposure) that are known to improve sleep in nondemented, institutionalized older adults.

Adult↗

PubMed2005

Isometric back extension endurance testing: reasons for test termination.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: The self-reported reasons for terminating isometric back extension endurance testing and their associations with test performance and other factors were investigated to gain insight into determinants of test performance. BACKGROUND: Factors limiting isometric back extension endurance performance remain unclear. Better understanding the reasons for termination of isometric extension endurance testing could provide insights into what the test actually reflects. METHODS AND MEASURES: Lifetime work, leisure activities and back pain questionnaire data, isometric back extension endurance testing (holding time, as measured in seconds), and reasons for test termination were obtained for a population-based sample of 544 working-age men. RESULTS: The most common reason for test termination was fatigue (62.5%), followed by pain in various parts of the lower extremities (12.6%) and back (3.2%). A history of daily low back pain over the prior 12 months and greater pain intensity of the worst back pain episode over the same period were associated with a greater likelihood of termination due to back pain. In a regression analysis, longer holding time was associated with stopping due to fatigue rather than low back pain, with a trend of 19 seconds (95% confidence interval [CI], -2-40) longer holding time. After controlling for low back pain history, those previously involved in competitive sports were 2.6 times more likely to stop due to pain. Those with a competitive sport history had 14 seconds (95% CI, 5-23) greater holding time than those without such a history. CONCLUSIONS: Isometric back extension endurance testing is most commonly reported to be terminated due to muscle-related capacity as indicated by fatigue. Back pain is more likely to decrease performance time in men with a history of significant (frequent, intense) low back symptoms.

Adult↗

PubMed2004

Anxiety and nighttime behavioral disturbances. Awakenings in patients with Alzheimer's disease.

This study was conducted to describe the relationship between anxiety and nighttime behavioral disturbance in a community-dwelling sample of patients with Alzheimer's disease (AD). Data from 153 patients with probable or possible AD and their family caregivers were analyzed using logistic regression modeling. Ratings of nighttime behavioral disturbance were based on caregiver reports of how often patients had awakened them at night during the past week. Standardized ratings for patient cognitive, functional, and behavioral status, and for caregiver sleep, depression, and burden were collected. Fifty-six percent of the patients with AD showed symptoms of anxiety, and 29% had awakened their caregiver at least once at night during the past week. Patient awakening was associated with higher levels of patient anxiety (odds ratio [OR] = 2.1; confidence Interval [CI] = 1.4, 2.9) and patient impairments in activities of daily living (OR = 1.6, CI = 1.2, 2.3). No other demographic, cognitive, functional, or behavioral variables were significant, including depression. In univariate analyses, individual patient anxiety symptoms (e.g., feeling anxious; showing physical signs of anxiety, agitation, and irritability) were significant risk factors for patient awakenings. Of these, showing physical signs of anxiety remained a significant risk factor in multivariate analyses. Results suggest that anxiety and nighttime awakening are highly interrelated in patients with moderate dementia due to AD, and treatments targeting both may be more efficacious than those focusing on anxiety or sleep alone. They also reveal the importance of assessing anxiety as well as depression in the research and clinical care of patients with AD.

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PubMed2003

Exercise plus behavioral management in patients with Alzheimer disease: a randomized controlled trial.

CONTEXT: Exercise training for patients with Alzheimer disease combined with teaching caregivers how to manage behavioral problems may help decrease the frailty and behavioral impairment that are often prevalent in patients with Alzheimer disease. OBJECTIVE: To determine whether a home-based exercise program combined with caregiver training in behavioral management techniques would reduce functional dependence and delay institutionalization among patients with Alzheimer disease. DESIGN, SETTING, AND PATIENTS: Randomized controlled trial of 153 community-dwelling patients meeting National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer Disease and Related Disorders Association criteria for Alzheimer disease, conducted between June 1994 and April 1999. INTERVENTIONS: Patient-caregiver dyads were randomly assigned to the combined exercise and caregiver training program, Reducing Disability in Alzheimer Disease (RDAD), or to routine medical care (RMC). The RDAD program was conducted in the patients' home over 3 months. MAIN OUTCOME MEASURES: Physical health and function (36-item Short-Form Health Survey's [SF-36] physical functioning and physical role functioning subscales and Sickness Impact Profile's Mobility subscale), and affective status (Hamilton Depression Rating Scale and Cornell Depression Scale for Depression in Dementia). RESULTS: At 3 months, in comparison with the routine care patients, more patients in the RDAD group exercised at least 60 min/wk (odds ratio [OR], 2.82; 95% confidence interval [CI], 1.25-6.39; P =.01) and had fewer days of restricted activity (OR, 3.10; 95% CI, 1.08-8.95; P<.001). Patients in the RDAD group also had improved scores for physical role functioning compared with worse scores for patients in the RMC group (mean difference, 19.29; 95% CI, 8.75-29.83; P<.001). Patients in the RDAD group had improved Cornell Depression Scale for Depression in Dementia scores while the patients in the RMC group had worse scores (mean difference, -1.03; 95% CI, -0.17 to -1.91; P =.02). At 2 years, the RDAD patients continued to have better physical role functioning scores than the RMC patients (mean difference, 10.89; 95% CI, 3.62-18.16; P =.003) and showed a trend (19% vs 50%) for less institutionalization due to behavioral disturbance. For patients with higher depression scores at baseline, those in the RDAD group improved significantly more at 3 months on the Hamilton Depression Rating Scale (mean difference, 2.21; 95% CI, 0.22-4.20; P =.04) and maintained that improvement at 24 months (mean difference, 2.14; 95% CI, 0.14-4.17; P =.04). CONCLUSION: Exercise training combined with teaching caregivers behavioral management techniques improved physical health and depression in patients with Alzheimer disease.

Activities of Daily Living↗

PubMed2003

Associations between back pain history and lumbar MRI findings.

STUDY DESIGN: Retrospective monozygotic twin cohort study. OBJECTIVES: Our goal was to investigate the associations between different spinal MRI findings and current, past year, and lifetime low back pain after adjusting for occupational physical loading, smoking, genetics, and early family influences. SUMMARY OF BACKGROUND DATA: The role of spinal pathology in back symptoms continues to be controversial. METHODS: The study participants consisted of 115 monozygotic male twin pairs 35 to 69 years of age. The qualitatively assessed MRI parameters were as follows: disc height, bulging, herniations, anular tears, osteophytes, spinal stenosis, and endplate changes. Signal intensity was measured quantitatively. RESULTS: After controlling for age, disc height was associated with all back pain variables studied and anular tears with LBP frequency and intensity during the 12 months before imaging. Both were associated with lifetime frequency of low back pain interfering with daily activities, disability, and intensity of the worst lifetime pain episode. Other MRI findings did not explain the various symptom histories. Adjusting for physical loading in the past 12 months increased the associations of anular tears and "low back pain today" and 12-month low back pain parameters. After controlling for genotype and other familial influences, the within-pair differences in disc height and anular tears accounted for 6% to 12% of the total variance in the within-pair differences of low back pain variables. CONCLUSION: These findings raise new questions about the underlying mechanisms of LBP. The sensitivities of the only significant MRI parameters, disc height narrowing and anular tears, are poor, and these findings alone are of limited clinical importance.

Adult↗

PubMed2003

Training caregivers to change the sleep hygiene practices of patients with dementia: the NITE-AD project.

OBJECTIVES: To examine the feasibility of training caregivers to implement sleep hygiene recommendations in dementia patients. DESIGN: A randomized, controlled trial. SETTING: Community. PARTICIPANTS: Twenty-two community-dwelling patients with Alzheimer's disease (AD) and their family caregivers. INTERVENTIONS: All participants received written materials describing age- and dementia-related changes in sleep and standard principles of good sleep hygiene. Caregivers in active treatment (n=10) also received specific recommendations about setting up and implementing a sleep hygiene program for the dementia patient. Control subjects (n=12) received general dementia education and caregiver support. MEASUREMENTS: Success implementing sleep hygiene recommendations was measured using daily log reports to calculate the percentage of days that caregivers reported that patients met individualized sleep scheduling, daytime-napping, and walking goals. RESULTS: Caregivers in active treatment were more successful in setting goals related to sleep scheduling and increasing daytime activity than control caregivers who received written materials only. Among patients who were candidates for sleep hygiene changes, active treatment subjects were also significantly (P<.01) more likely than controls to maintain a consistent bedtime (83% vs 38% of days attempted) and a consistent rising time (96% vs 59%), to nap less during the day (70% vs 28%), and to walk daily (86% vs 7%). CONCLUSION: This study provides evidence that sleep hygiene interventions are feasible with community-dwelling AD patients. Caregivers were able to help patients change sleep scheduling, napping, and walking routines, but clinicians who recommend sleep hygiene changes for their dementia patients should be aware that many caregivers need active assistance setting up and implementing a sleep hygiene program. Simply providing caregivers with education is often insufficient.

Aged↗

PubMed2003

Chronic pain in a large community sample of persons with multiple sclerosis.

INTRODUCTION: This study examined the prevalence, intensity, interference, and biopsychosocial correlates of pain in a large community-based sample of persons with multiple sclerosis (MS). METHODS: Mail surveys were returned by 442 members of the King County (WA) MS Association. Average pain intensity, pain-related activity interference, depressive symptoms and severity of MS were assessed. RESULTS: Forty-four percent reported persistent, bothersome pain in the three months prior to completing the survey. Participants with pain reported an average pain intensity rating of 5.2 (SD = 2.3) on the 0 (no pain) to 10 (pain as bad as could be) scale. Twenty-seven percent reported severe pain (score of 7-10), while 51% of those with pain rated the interference of their pain with daily activities as none to minimal. Twenty percent reported severe interference in activities as a result of pain. In multivariate modeling, MS illness severity, marital status, and self-ratings of overall health were significantly associated with pain-related interference with activities. CONCLUSIONS: Approximately a fourth of this sample described having a chronic pain problem characterized by severe pain intensity and significant pain-related interference with activities. Disability due to pain may be more important than previously recognized for the MS population.

Activities of Daily Living↗

PubMed2002

Occupational driving and lumbar disc degeneration: a case-control study.

BACKGROUND: Back problems are reported more by occupational drivers than by any other occupational group. One explanation is that whole-body vibration caused by the vehicle leads to accelerated disc degeneration, herniation, and associated symptoms. We aimed to investigate the effects of lifetime driving exposure on lumbar disc degeneration in monozygotic twins with very different histories of occupational driving during their life. METHODS: We assessed 45 male monozygotic twin pairs from the population-based Finnish Twin Cohort who had greatly different patterns of occupational driving during their life. Data were obtained for driving exposures and potential confounding factors through an extensive, structured interview. We assessed disc degeneration with lumbar MRI. FINDINGS: Disc degeneration did not differ between occupational drivers and their twin brothers. We also did not identify any overall tendency for greater degeneration or pathology in occupational drivers than their twin brothers. INTERPRETATIONS: Although driving may exacerbate symptoms of back problems, it does not damage the disc. Our inability to identify structural damage should be encouraging to those employed in occupations involving motorised vehicles and operation of heavy equipment.

Automobile Driving↗

PubMed2002

Cross-cultural comparison of the Mini-Mental State examination in United Kingdom and United States participants with Alzheimer's disease.

OBJECTIVES: the relative difficulties of items on the Mini-Mental State Examination (MMSE) were compared in English-speaking Alzheimer's disease (AD) patients in the United States (US) and United Kingdom (UK). METHODS: participants were aged 75 and over, with a clinical diagnosis of AD according to standardized methods. Initial MMSE scores from an AD patient registry in the US (n = 401), and a field survey in the UK (n = 139) were compared. Item Characteristic Curve analysis (ICC) was used to calculate the relative difficulty of individual MMSE items, adjusted for the remaining MMSE items. Age, gender, education, and severity of disease were evaluated as possible confounders. RESULTS: UK participants found it relatively more difficult to name their county than US participants did to name their state. The relative difficulties of registration and recall, repeating a phrase, and following verbal directions also were significantly higher for the UK participants, even after adjustment for other factors. CONCLUSIONS: differences between the cohorts could be explained by translation artifacts in the test items or by cultural differences in the manifestation of AD. In this study, most, if not all differences can be explained by the former. ICC analysis can be used to develop tests that are functionally equivalent, a prerequisite for comparing dementia in different populations.

Aged↗

PubMed2002

Older adults and functional decline: a cross-cultural comparison.

BACKGROUND: The study was conducted to examine the relationships between functional decline, health risk factors, lifestyle practices, and demographic variables in two culturally diverse, community-based samples of White and Japanese American older adults. DESIGN: The study was an analysis of data from two ongoing studies of aging and dementia in King County, Washington. Functional status at baseline was evaluated, and factors associated with functional decline over a 4-year follow-up period were identified. The sample included 1,083 Japanese American and 1,011 White cognitively intact, community-dwelling adults aged 65 and older, who had no functional limitations at baseline and participated in at least one follow-up examination. RESULTS: In 4 years of follow-up, 70% of the subjects reported no increase in functional limitation, and fewer than 5% of subjects declined in five or more activities. Risk factors associated with functional decline included increased age, female gender, medical comorbidity (particularly cerebrovascular disease, arthritis, and hypertension), elevated body mass index, poorer self-perceived health, and smoking. Depression and diabetes were also significant for persons with the greatest functional decline over the 4-year follow-up. Japanese speakers were significantly less likely to decline over the follow-up period than White or English-speaking Japanese American subjects. However, Japanese speakers were more likely to discontinue participation during the follow-up period, and may also have been more likely to underreport symptoms of functional decline. CONCLUSIONS: The present study provides further support that healthy lifestyle practices and prevention of chronic disease are important for maintaining functional independence in older adults. Japanese-speaking subjects were less likely to decline over time, although this could be due in part to differential dropout and reporting bias. These findings have important implications for the design and interpretation of longitudinal studies of older adults. Researchers interested in the effects of ethnicity on health and aging should be cognizant of differences in recruitment and enrollment strategies among studies, and the ways in which these affect study findings. This study also demonstrates the importance of devoting adequate resources to minimize dropouts, and of including measures of health and functioning that are culturally equivalent and less reliant on self-report data.

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