The timing of change: patterns in transitions in functional status among elderly persons

Factors Related to Diabetes Mellitus in the Middle-Aged and Over in Taiwan

Study Objective: to investigate the factors related to diabetes mellitus in the middle-aged and over in Taiwan. Method: data from seven surveys (in 1989–2011) from the “Taiwan Longitudinal Study on Aging” (TLSA), among cohort B (above the age 60 in 1989), cohort A (aged 50–66 in 1996), and cohort C (aged 50–66 in 2003), were analyzed by the interval-censored Cox model. Results: in the early aging stage (aged 60–64), diabetes mellitus prevalence among the same age appeared the lowest in cohort B, followed by cohort A; cohort C reveals the highest than the young generation. Moreover, suffering from hypertension and kidney diseases are closely related to diabetes mellitus, with the diabetes mellitus suffering hazard ratio of 2.53 (95%: 2.35, 2.73) and 1.26 (95%: 1.11, 1.44) times, respectively. For people with fair and poor self-rated health, the risk of suffering from diabetes mellitus is 1.16 (95%: 1.07, 1.27) and 1.50 (95%: 1.35, 1.67) times compared to people with good self-rated health, respectively. Conclusions: in this study, it is considered that an advanced interval censoring model analysis could more accurately grasp the characteristics of factors in people who are middle-aged and over suffering from diabetes mellitus in Taiwan.

Social vulnerability underlying disability amongst older adults: A systematic review

BACKGROUND

Older adults face radical changes in their social life during ageing, dealing with several age-related social adaptations. The aim of this review is to systematically explore the literature on social vulnerability (SV) and its association with functional decline activity of daily living (ADL)/instrumental activities of daily living (IADL) as an endpoint in older adults.

METHODS

We searched for relevant studies in three different databases: PubMed, Ovid Medline and PsychInfo. Inclusion criteria included: prospective cohort studies assessing SV correlation; studies in English, Italian, French and Spanish to the end of March 2018; a general population aged >65 years living in a community setting and/or studies including younger participants if the mean age was >65 years; and basic ADL and/or IADL by Katz and Lawton, respectively, as functional decline and clinical outcomes.

RESULTS

We identified 65 manuscripts that assessed the role of SV in functional decline. Our systematic analysis showed that 26, 36 and 19 studies observed a correlation between Basic Social Needs, Social Resources and Social Behaviour and Activity, respectively, and the onset of ADL/IADL functional decline. Twenty-six studies explored the correlation between General Social Resources and the onset of ADL/IADL functional decline.

CONCLUSIONS

When examining a wide set of social variables, the "quality," rather than just structure, and "type" of social relationship represents the core feature of SV that predicts functional decline in older adults. By defining individual SV, its measurement and evaluation, we can plan effective social interventions aimed at preventing or delaying functional decline or death.

Urban-rural difference in the associations between living arrangements and the health-related quality of life (HRQOL) of the elderly in China-Evidence from Shaanxi province

BACKGROUND

So far limited evidence exist comparing the difference between urban and rural elder residents in relation to how living arrangements correlates to health-related quality of life(HRQOL) of the elderly.

OBJECTIVE

This study aims to compare the HRQOL of the elderly with four living arrangements: living with spouse only (LS), living alone (LA), living with a spouse and adult children(LSC) and the single elderly living with adult children (SLC) in urban and rural areas of China.

METHODS

The data were drawn from the 2013 wave of Chinese National Health Service Survey in Shaanxi Province, which included 11,729 elderly people. The Chinese version of the EQ-5D-3L questionnaire was used to measure the HRQOL. Tobit regression model and logistic regression models were employed to estimate the associations between living arrangements and the HRQOL of the elderly.

RESULTS

The EQ-5D utility scores of the urban elderly with four different living arrangements (LS, LA,LSC and SLC) were 0.9141, 0.8392, 0.8176 and 0.9080, which were almost all higher than their rural counterparts. After controlling other confounding variables, tobit regression estimates showed that the EQ-5D utility scores of the single elderly either living alone or living with adult children were lower than the elderly living with a spouse in urban areas. In rural areas only the single elderly living with adult children were more disadvantaged. Additionally the logistic regression results showed living-alone elderly had worse psychological health and the single elderly living with adult children had worse physical health.

CONCLUSION

The findings suggest that the urban elderly have better HRQOL than the rural elderly and the elderly with different living arrangements in urban and rural area have different HRQOL. More attention should be given to the poor mental health of the elderly living alone and the worse physical health of the single elderly living with adult children.

Prediction of functional decline in community-dwelling older persons in general practice: a cohort study

BACKGROUND

A first step to offer community-dwelling older persons proactive care is to identify those at risk of functional decline within a year. This study investigates the predictive value of registered information, questionnaire and GP-opinion on functional decline.

METHODS

In this cohort study, embedded within the ISCOPE-trial, participants (≥75 years) completed the ISCOPE-screening questionnaire on four health domains. GPs gave their opinion on vulnerability of participants. Functional status was measured at baseline and 12 months (Groningen Activities Restriction Scale [GARS]). The outcome was functional decline (death, nursing home admission, 10% with greatest functional decline). The predictive value of pre-selected variables (age, sex, polypharmacy, multimorbidity, living situation; GPs' opinion on vulnerability, number of domains with problems [ISCOPE-score]) was compared with the area under the curves (AUC) for logistic regression models.

RESULTS

2018 of the 2211 participants (median age 82.1 years [IQR 78.8-86.5], 68.0% female, median GARS 31 [IQR 24-41]) were visited at 12 months (median GARS 34 [IQR 26-44]). 394 participants (17.8%) had functional decline (148 died, 45 nursing home admissions, 201 with greatest functional decline). The AUC for age and sex was 0.602, increasing to 0.620 (p = 0.029) with polypharmacy, multimorbidity and living situation. The GPs' opinion added more (AUC 0.672, p < 0.001) than the ISCOPE-score (AUC 0.649, p = 0.007). AUC with all variables was 0.686 (p = 0.016), and 0.643 for GPs' opinion alone.

CONCLUSIONS

The GPs' opinion and ISCOPE-score improve this prediction model for functional decline based on readily available variables. GPs could identify older patients for further assessment with their clinical judgement.

TRIAL REGISTRATION

Netherlands trial register, NTR1946 . Registered 10 August 2009.

Disability Experience and Measurement

Top themes of international research on disability in the past three decades are discussed: disability dynamics, buffers and barriers for disability, disability trends, and disability among very old persons. Each theme is highlighted by research examples. Turning to measurement, I discuss traditional measures of disability, new longer and shorter ones, and composites like disability-free life expectancy, noting their merits. Contemporary models of disability are presented, ranging from visual images to formal theories. The article ends on how scientists can facilitate movement of disability science into health care practice and policy.

Trajectories of ADL Disability Among Community-Dwelling Frail Older Persons

This study examines how activity of daily living (ADL) disability of community-living frail elders changes in a two-year period and how the pattern of change varies between those who subsequently died or were institutionalized and those who continued to live in the community. Multiple waves of data from a cohort of older participants ( N = 3,161) in Michigan’s Medicaid Waiver Program were analyzed using the hierarchical linear modeling (HLM) approach. The results suggest that changes in ADL disability were nonlinear and the pattern of change varied by their subsequent status. Participants who subsequently died or were institutionalized exhibited a steep increase in ADL disability during the last few months before the events, whereas continued community residents were relatively stable in ADL disability during the two-year study period. Within each group, substantial individual variation in ADL disability trajectories exists. Implications of the findings to research and practice are discussed.

A Didactic Example of Latent Curve Analysis Applicable to the Study of Aging

Objectives: This article provides an example and application of growth curve analysis for modeling individual differences in behavioral rates of change in aging. The latent curve modeling approach to the analysis of change allows researchers to describe change as a continuous process and to address issues related to individual differences in change over time. Methods: Data are used from the Longitudinal Study of Aging (LSOA) on change in activities of daily living (ADLs) in the elderly. Analyses involved direct maximum likelihood estimation using complete and incomplete cases. Results: It is possible to statistically capture developmental changes. Change in participants’ ADLs was characterized by a negative linear trajectory, and there was evidence of significant individual variability in the starting point of the trajectory and the rate of change over time. Discussion: The article discusses the utility of latent curve analysis in aging research as well as other techniques that are extensions of latent curve analysis.

Using Multiple-hierarchy Stratification and Life Course Approaches to Understand Health Inequalities: The Intersecting Consequences of Race, Gender, SES, and Age

This study examines how the intersecting consequences of race-ethnicity, gender, socioeconomics status (SES), and age influence health inequality. We draw on multiple-hierarchy stratification and life course perspectives to address two main research questions. First, does racial-ethnic stratification of health vary by gender and/or SES? More specifically, are the joint health consequences of racial-ethnic, gender, and socioeconomic stratification additive or multiplicative? Second, does this combined inequality in health decrease, remain stable, or increase between middle and late life? We use panel data from the Health and Retirement Study (N = 12,976) to investigate between- and within-group differences in in self-rated health among whites, blacks, and Mexican Americans. Findings indicate that the effects of racial-ethnic, gender, and SES stratification are interactive, resulting in the greatest racial-ethnic inequalities in health among women and those with higher levels of SES. Furthermore, racial-ethnic/gender/SES inequalities in health tend to decline with age. These results are broadly consistent with intersectionality and aging-as-leveler hypotheses.

Common trajectories of physical functioning in the Doetinchem Cohort Study

PURPOSE

to describe common trajectories of physical functioning and their determinants among an adult cohort, followed over a period of 15 years.

METHODS

the study sample consisted of 4,123 participants (initial ages 26-70 years) from the Doetinchem Cohort Study, who participated in three or four measurement cycles. Physical functioning was measured with the Dutch version of the SF-36. Using a group-based modelling strategy, trajectories of physical functioning were determined. Weighted multinomial logistic regression analyses were performed to identify socio-demographic, lifestyle and health characteristics that differentiate between the trajectories at baseline.

RESULTS

five common physical functioning trajectories were distinguished, labelled as 'stable not limited' (27% of the population), 'stable slightly limited' (54%), 'slightly limited substantial deterioration' (7%), 'moderately limited gradual improvement' (9%) and 'stable severely limited' (3%). The characteristics that differentiate between the trajectories with limitations and the trajectory 'stable not limited' were being female, older, physically inactive, overweight or obese, having one or more chronic conditions, poor mental health and poor self-perceived health at baseline. Being younger, physically active, less obese, living with a partner and a good perceived health were characteristics of the trajectory 'moderately limited gradual improvement' compared with 'stable severely limited'.

CONCLUSION

five common trajectories of physical functioning were distinguished in an adult cohort, with most individuals following a stable but slightly limited course of physical functioning. Some early risk indicators were found that in the future might be used to early identify those with limitations in physical functioning.

The progression of disability among older adults in Mexico

PURPOSE

This paper seeks to document the progression of disability in a developing country and to examine gender differences in this process.

METHODS

The data come from the Mexican Health and Aging Study (MHAS), a nationally representative sample of older adults. An ordinal logistic regression (n = 3283) is used to measure the progression of disability that considers: (1) no disability, (2) mobility problems, (3) mobility problems with IADLs limitations, (4) mobility problems with ADLs limitations, (5) combinations of the latter three and (6) death.

RESULTS

Approximately 43% of the sample remained in the same level of disability after 2 years. The patterns of progression with two disabilities differ for men and women.

CONCLUSIONS

Our model reflects the importance of separating ADLs and IADLs in the study of disability progression in Mexico. Varying risk profiles and cultural differences might influence the divergent disability paths followed by each gender. Implications for Rehabilitation The disablement process involving transitions from mobility impairments to IADL and ADL limitations seen in developed countries differs for older adults in Mexico. Cultural differences may influence the progression from non-disabled to becoming disabled in different ways for females in developing countries like Mexico. One-fifth of individuals showed greater function and independence over time, suggesting that the disablement process is reversible. This finding highlights the need to focus on improving mobility, ADL, and IADL skills to facilitate successful aging. Although disability is often conceptualised as a combination of ADL and IADL limitations, gender differences seen in Mexico indicate the need to separate ADL and IADL when developing approaches to prevent or ameliorate disability.

Multiple chronic conditions and limitations in activities of daily living in a community-based sample of older adults in New York City, 2009

Introduction

Nationally, 60% to 75% of older adults have multiple (2 or more) chronic conditions (MCCs), and the burden is even higher among low-income, racial/ethnic minority populations. MCCs limit activities of daily living (ADLs), yet this association is not well characterized outside of clinical populations. We examined the association of MCCs with ADLs in a racially/ethnically diverse population of low-income older adults living in New York City public housing.

Methods

A representative sample of 1,036 New York City Housing Authority residents aged 65 or older completed a telephone survey in June 2009. We examined the association of up to 5 chronic conditions with basic ADL (BADL) limitations, adjusting for potential confounders by using logistic regression.

Results

Of respondents, 28.7% had at least 1 BADL limitation; 92.9% had at least 1 chronic condition, and 79.0% had MCCs. We observed a graded association between at least 1 BADL limitation and number of chronic conditions (using 0 or 1 condition as the reference group): adjusted odds ratio (AOR) for 3 conditions was 2.2 (95% confidence interval [CI], 1.3–3.9); AOR for 4 conditions, 4.3 (95% CI, 2.5–7.6); and AOR for 5 conditions, 9.2 (95% CI, 4.3–19.5).

Conclusion

Prevalence of BADL limitations is high among low-income older adults and increases with number of chronic conditions. Initiating prevention of additional conditions and treating disease constellations earlier to decrease BADL limitations may improve aging outcomes in this population.

Activity of daily living trajectories surrounding acute hospitalization of long-stay nursing home residents

OBJECTIVES

To explore patterns of change in nursing home (NH) residents' activities of daily living (ADLs), particularly surrounding acute hospital stays.

DESIGN

Longitudinal study using Medicare and Minimum Data Set (MDS) assessments.

SETTING

National sample of long-stay NH residents.

PARTICIPANTS

NH residents who were hospitalized for the seven most-common inpatient diagnoses (N = 40,128). Each hospital admission was at least 90 days after any prior hospitalization and had at least two preceding MDS assessments.

MEASUREMENTS

The MDS ADL long-form score, a simple sum of seven self-care variables coded from 0 (independent) to 4 (totally dependent) was used to indicate resident ADL function. Scores ranged from 0 to 28, with higher scores indicating greater impairment. A linear mixed model describing ADL trajectories was jointly estimated with time-to-event models for mortality and hospital readmission.

RESULTS

Before hospitalization, the most common trajectory was stable (53.7%), with 27.5% of residents worsening and 18.8% improving. ADL function after hospital discharge was most often characterized as stable (43.1%) or worsening (39.2%). Mortality (20.3%) was higher for those with worsening prehospital ADL function (28.9%) than for those with stable (19.1%) or improving (11.3%) trajectories. Hospital diagnosis was associated with amount of ADL worsening and rate of subsequent ADL change. Most residents with the best initial function continued to worsen after hospital discharge. Cognitive impairment was associated with poorer ADL function and accelerated worsening of ADLs.

CONCLUSION

For many long-stay NH residents, substantial and sustained ADL worsening accompanies acute hospitalization, so acute hospitalization presents an opportunity to revisit care goals; the results of the current study can help inform decision-making.

Using group-based latent class transition models to analyze chronic disability data from the National Long-Term Care Survey 1984-2004

Latent class transition models track how individuals move among latent classes through time, traditionally assuming a complete set of observations for each individual. In this paper, we develop group-based latent class transition models that allow for staggered entry and exit, common in surveys with rolling enrollment designs. Such models are conceptually similar to, but structurally distinct from, pattern mixture models of the missing data literature. We employ group-based latent class transition modeling to conduct an in-depth data analysis of recent trends in chronic disability among the U.S. elderly population. Using activities of daily living data from the National Long-Term Care Survey (NLTCS), 1982-2004, we estimate model parameters using the expectation-maximization algorithm, implemented in SAS PROC IML. Our findings indicate that declines in chronic disability prevalence, observed in the 1980s and 1990s, did not continue in the early 2000s as previous NLTCS cross-sectional analyses have indicated.

Prognosis for functional deterioration and functional improvement in late life among community-dwelling persons

OBJECTIVE

To examine how health-related, socioeconomic, and environmental factors combine to influence the onset of activity of daily living (ADL) limitations or prognosis for death or further functional deterioration or improvement among elderly people.

DESIGN

A national representative sample with 2-year follow-up.

SETTING

Community-dwelling people.

PARTICIPANTS

Included were 9447 persons (≥70 years of age) in the United States from the Second Longitudinal Study of Aging who were interviewed in 1994, 1995, or 1996.

METHODS

Self- or proxy-reported health conditions, ADLs expressed as 5 stages describing severity and pattern of limitations, and other baseline characteristics were obtained. A multinomial logistic regression model was used to predict stage transitions. Because of incomplete follow-up (17.7% of baseline sample), primary analyses were determined by multiple imputation to address potential bias associated with loss to follow-up.

MAIN OUTCOME MEASUREMENT

ADL stage transitions in 2 years (death, deteriorated, stable, and improved ADL function).

RESULTS

In the imputed-case analysis, the percentages for those who died, deteriorated, were stable, and improved were 12.6%, 32.7%, 48.4%, and 6.2%, respectively. Persons at a mild stage of ADL limitation were most likely to deteriorate further. Persons at advanced stages were most likely to die. Married people and high school graduates had a lower likelihood of deterioration. The risk of mortality and functional deterioration increased with age. Certain conditions, such as diabetes, were associated both with mortality and functional deterioration; other conditions, such as cancer, were associated with mortality only, and arthritis was associated only with functional deterioration.

CONCLUSIONS

Although overlap occurs, different clinical traits are associated with mortality, functional deterioration, and functional improvement. ADL stages might aid physical medicine and rehabilitation clinicians and researchers in developing and monitoring disability management strategies targeted to maintaining and enhancing self-care among community-dwelling older people.

Correlates of Functional Capacity Among Centenarians

This study investigated correlates of functional capacity among participants of the Georgia Centenarian Study. Six domains (demographics and health, positive and negative affect, personality, social and economic support, life events and coping, distal influences) were related to functional capacity for 234 centenarians and near centenarians (i.e., 98 years and older). Data were provided by proxy informants. Domain-specific multiple regression analyses suggested that younger centenarians, those living in the community and rated to be in better health were more likely to have higher functional capacity scores. Higher scores in positive affect, conscientiousness, social provisions, religious coping, and engaged lifestyle were also associated with higher levels of functional capacity. The results suggest that functional capacity levels continue to be associated with age after 100 years of life and that positive affect levels and past lifestyle activities as reported by proxies are salient factors of adaptation in very late life.

Survey disability questionnaire does not generate valid accurate data compared to clinical assessment on an older population

PURPOSE

Policy-makers and health care managers need accurate information on disabilities in the population to plan appropriate services to the older population. Disability information from population surveys are often very crude as compared to information used on the clinical field. This study aimed to verify the concurrent validity of a survey questionnaire version of a disability instrument (SMAF) administered by lay interviewers, compared to the original SMAF rating scale completed by clinicians.

METHODS

The survey questionnaire version was developed by a panel of experts and pretested with 15 patients attending a day hospital program using a think-aloud approach. A social worker administered the SMAF rating scale at home to a sample of Community-dwelling frail people over 81 years old who participated in the PRISMA longitudinal study in Sherbrooke, Québec, Canada. The same subjects were contacted one month later by a lay interviewer, who completed the survey questionnaire. The two versions were compared using intraclass correlation coefficients (ICCs) and weighted kappas (WK).

RESULTS

96 subjects participated in the study. The ICC was 0.82 for the total SMAF score and ranged from 0.46 (mental functions) to 0.82 (IADL) for the subscores. The questionnaire version systematically underestimated disability by 4.7 points on average (out of 87) (p<0.0001). For the case-mix classification generated from the disability assessment (Iso-SMAF profiles), the underestimation was even more striking.

CONCLUSIONS

A survey questionnaire is not a valid method for accurately estimating disability in a population.

Understanding how race/ethnicity and gender define age-trajectories of disability: an intersectionality approach

A number of studies have demonstrated wide disparities in health among racial/ethnic groups and by gender, yet few have examined how race/ethnicity and gender intersect or combine to affect the health of older adults. The tendency of prior research to treat race/ethnicity and gender separately has potentially obscured important differences in how health is produced and maintained, undermining efforts to eliminate health disparities. The current study extends previous research by taking an intersectionality approach (Mullings & Schulz, 2006), grounded in life course theory, conceptualizing and modeling trajectories of functional limitations as dynamic life course processes that are jointly and simultaneously defined by race/ethnicity and gender. Data from the nationally representative 1994-2006 US Health and Retirement Study and growth curve models are utilized to examine racial/ethnic/gender differences in intra-individual change in functional limitations among White, Black and Mexican American Men and Women, and the extent to which differences in life course capital account for group disparities in initial health status and rates of change with age. Results support an intersectionality approach, with all demographic groups exhibiting worse functional limitation trajectories than White Men. Whereas White Men had the lowest disability levels at baseline, White Women and racial/ethnic minority Men had intermediate disability levels and Black and Hispanic Women had the highest disability levels. These health disparities remained stable with age-except among Black Women who experience a trajectory of accelerated disablement. Dissimilar early life social origins, adult socioeconomic status, marital status, and health behaviors explain the racial/ethnic disparities in functional limitations among Men but only partially explain the disparities among Women. Net of controls for life course capital, Women of all racial/ethnic groups have higher levels of functional limitations relative to White Men and Men of the same race/ethnicity. Findings highlight the utility of an intersectionality approach to understanding health disparities.

Promoting functional health in midlife and old age: long-term protective effects of control beliefs, social support, and physical exercise

Background

Previous studies have examined physical risk factors in relation to functional health, but less work has focused on the protective role of psychological and social factors. We examined the individual and joint protective contribution of control beliefs, social support and physical exercise to changes in functional health, beyond the influence of health status and physical risk factors in middle-aged and older adults. Given that functional health typically declines throughout adulthood, it is important to identify modifiable factors that can be implemented to maintain functioning, improve quality of life, and reduce disability.

Methodology/Principal Findings

We conducted a national longitudinal study, Midlife in the United States (MIDUS), with assessments in 1995–1996 and 2004–2006, and 3,626 community-residing adults, aged 32 to 84, were included in the analyses. Functional health (Physical Functioning subscale of the SF-36) and protective factors were measured at both occasions. While controlling for socio-demographic, health status, and physical risk factors (large waist circumference, smoking, and alcohol or drug problems), a composite of the three protective variables (control beliefs, social support, and physical exercise) at Time 1 was significantly related to functional health change. The more of these factors at Time 1, the better the health maintenance over 10 years. Among middle-aged and older adults, declines in health were significantly reduced with an increased number of protective factors.

Conclusion/Significance

Age-related declines in health were reduced among those with more protective factors up to a decade earlier in life. Modifiable psychological, social, and physical protective factors, individually and in the aggregate, are associated with maintenance of functional health, beyond the damaging effects of physical risk factors. The results are encouraging for the prospect of developing interventions to promote functional health and for reducing public health expenditures for physical disability in later life.

Trajectory of functional status among older Taiwanese: Gender and age variations

Current findings on gender and age differences in health trajectories in later life are equivocal and largely based upon data derived from Western developed nations. This study examines gender and age variations in the trajectory of functional status among older adults in Taiwan, a non-Western newly industrialized society. Data came from a sample of some 3500 Taiwanese aged 60 and over, initially surveyed in 1989 and subsequently followed in 1993, 1996, 1999, and 2003. Hierarchical linear models with time-varying covariates were employed in depicting the dynamics of functional status across gender and age. Women and the old-old experienced higher levels of disability and rates of increase than their male and young-old counterparts. Moreover, older women bore a disproportionately larger burden of disability. There are therefore significant gender and age variations in the trajectory of functional status among older Taiwanese. These findings provide evidence for the generalizability of prior observations to a non-Western society.

The dwelling-type choices of older Canadians and future housing demand: an investigation using the Aging and Social Support Survey (GSS16)

Using the 2002 Aging and Social Support Survey (GSS16), multinomial logit regression, and cohort-component projection techniques, this study explored how social support networks, health, and economic characteristics have shaped the residential choices of older Canadians, and predicts how they are likely to do so in the future. It focused on the distribution of 55-to-75-year-olds across three private-dwelling types: general community living, age-restricted housing, and age-restricted housing with nursing care. The analysis shows that social support characteristics are the strongest predictors of dwelling type, meaning that individuals appear to choose their dwellings largely on the basis of their social needs and wants, rather than on their economic or health characteristics. The analysis also indicates an increased age-specific demand for all dwelling types in the future, but with a reduction of over 2 million older Canadians living in dwellings in the general community between 2002 and 2022.

Childhood socioeconomic position and disability in later life: results of the health and retirement study

OBJECTIVES

We used a life course approach to assess the ways in which childhood socioeconomic position may be associated with disability in later life.

METHODS

We used longitudinal data from the nationally representative Health and Retirement Study (1998-2006) to examine associations between parental education, paternal occupation, and disabilities relating to activities of daily living (ADLs) and instrumental activities of daily living (IADLs).

RESULTS

Respondents whose fathers had low levels of education and those whose fathers were absent or had died while they were growing up were at increased risk of disability in later life, net of social, behavioral, and pathological health risks in adulthood. Social mobility and health behaviors were also important factors in the association between low childhood socioeconomic position and ADL and IADL disabilities.

CONCLUSIONS

Our findings highlight the need for policies and programs aimed at improving the well-being of both children and families. A renewed commitment to such initiatives may help reduce health care costs and the need for people to use health and social services in later life.

Joint modeling of self-rated health and changes in physical functioning

Self-rated health is an important indicator of future morbidity and mortality. Past research has indicated that self-rated health is related to both levels of and changes in physical functioning. However, no previous study has jointly modeled longitudinal functional status and self-rated health trajectories. We propose a joint model for self-rated health and physical functioning that describes the relationship between perceptions of health and the rate of change of physical functioning or disability. Our joint model uses a non-homogeneous Markov process for discrete physical functioning states and connects this to a logistic regression model for "healthy" versus "unhealthy" self-rated health through parameters of the physical functioning model. We use simulation studies to establish finite sample properties of our estimators and show that this model is robust to misspecification of the functional form of the relationship between self-rated health and rate of change of physical functioning. We also show that our joint model performs better than an empirical model based on observed changes in functional status. We apply our joint model to data from the Cardiovascular Health Study (CHS), a large, multi-center, longitudinal study of older adults. Our analysis indicates that self-rated health is associated both with level of functioning as indicated by difficulty with activities of daily living (ADL) and instrumental activities of daily living (IADL), and the risk of increasing difficulty with ADLs and IADLs.

Longitudinal characterization of course types of functional limitations

PURPOSE

Longitudinal data have provided evidence on factors that increase the risk of incidence of functional limitations. However, little insight exists in course types of functional limitations other than simple incidence or recovery.

METHODS

This contribution examines the variety of course types across the first three cycles of the Longitudinal Aging Study Amsterdam (n = 3107, initial ages 55 - 85 years, 6-year period covered). Using cluster analysis, course types were determined among both the survivors and the deceased. Multinomial analyses were performed to determine the predictive ability of baseline physical and mental chronic conditions for each course type.

RESULTS

Eight course types were distinguished: (1) stable not limited (53%) (2) stable mild (8%) (3) stable severe (3%) (4) gradual increase (4%) (5) delayed increase (5%) (6) not limited, died t3 (8%) (7) increase t1-t2, died t3 (4%) (8) died t2 (15%). Socio-demographic and chronic conditions differentially predicted the course types. Arthritis was predictive mainly of course types not ending in death, cancer of course types ending in death. The other physical and mental conditions were predictive of both.

CONCLUSION

These longitudinal data show the usefulness of distinguishing between course types of functional limitations beyond incidence and recovery.

How are personality traits related to preparation for future care needs in older adults?

We investigated associations between personality and health cognitions and behaviors related to preparation for future care among 355 primary care patients who were 65 years of age and older. Path analyses examined the effects of the personality traits of neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness on health cognitions about future care (avoidance, awareness), health-planning behaviors (gathering information, decision making, and planning), and beliefs about planning, while covarying age, gender, education, medical burden, functional status, and depression-symptom severity. Higher levels of neuroticism, openness, and agreeableness were associated with greater awareness of care needs; higher openness was also associated with more gathering of information and less avoidance. Extraversion and conscientiousness were not related to future-oriented health cognitions. Depression was inversely associated with the gathering of information. Age and education were related to more positive beliefs about the planning. Neither concrete planning nor decision making were related to personality variables. Health professionals should consider the impact of individual differences when addressing preparation for future care with older adults.

Evaluation of a method for fitting a semi-Markov process model in the presence of left-censored spells using the Cardiovascular Health Study

We used a longitudinal data set covering 13 years from the Cardiovascular Health Study to evaluate the properties of a recently developed approach to deal with left censoring that fits a semi-Markov process (SMP) model by using an analog to the stochastic EM algorithm--the SMP-EM approach. It appears that the SMP-EM approach gives estimates of duration-dependent probabilities of health changes similar to those obtained by using SMP models that have the advantage of actual duration data. SMP-EM estimates of duration-dependent transition probabilities also appear more accurate and less variable than multi-state life table estimates.

Health status transitions in community-living elderly with complex care needs: a latent class approach

Background

For older persons with complex care needs, accounting for the variability and interdependency in how health dimensions manifest themselves is necessary to understand the dynamic of health status. Our objective is to test the hypothesis that a latent classification can capture this heterogeneity in a population of frail elderly persons living in the community. Based on a person-centered approach, the classification corresponds to substantively meaningful groups of individuals who present with a comparable constellation of health problems.

Methods

Using data collected for the SIPA project, a system of integrated care for frail older people (n = 1164), we performed latent class analyses to identify homogenous categories of health status (i.e. health profiles) based on 17 indicators of prevalent health problems (chronic conditions; depression; cognition; functional and sensory limitations; instrumental, mobility and personal care disability) Then, we conducted latent transition analyses to study change in profile membership over 2 consecutive periods of 12 and 10 months, respectively. We modeled competing risks for mortality and lost to follow-up as absorbing states to avoid attrition biases.

Results

We identified four health profiles that distinguish the physical and cognitive dimensions of health and capture severity along the disability dimension. The profiles are stable over time and robust to mortality and lost to follow-up attrition. The differentiated and gender-specific patterns of transition probabilities demonstrate the profiles' sensitivity to change in health status and unmasked the differential relationship of physical and cognitive domains with progression in disability.

Conclusion

Our approach may prove useful at organization and policy levels where many issues call for classification of individuals into pragmatically meaningful groups. In dealing with attrition biases, our analytical strategy could provide critical information for the planning of longitudinal studies of aging. Combined, these findings address a central challenge in geriatrics by making the multidimensional and dynamic nature of health computationally tractable.

Gender differences in hazard rate affecting death in the elderly population in Taiwan

As the age-specific mortality of women is lower than that of men, feminization of later life is becoming common in all societies. Although elderly women enjoy lower mortality, the health status of women is not necessarily better than that of men. In this study, the mortality change, characteristics of the elderly population, and the trend of feminization in later life in Taiwan was reviewed. Various measures which are used to analyze the gender differences of health status among Taiwan's elderly, and estimation of the effects of factors influencing health were discussed using data from The Survey of Health and Living Status of the Elderly in Taiwan, published by The Department of Health in the Bureau of Health Promotion. The patterns of diseases, functional status, self-rated health and causal relationships among them were also investigated. The hazard rate model was employed to compare the dynamics of health and the functional status for men and women. The probability of being institutionalized and/or death for women is lower than for men for all functional status. However, the health status of women is not significantly better than men. Elderly women are less affected by fatal diseases but have more benign diseases restricting motion and function, which unexpectedly extends the effects of being more cautious, and, therefore, women live longer. The influence of self-rated health and functional status to hazard rate of death for both genders was equivalent and coincides with what was previously anticipated.

Predicting change in functional status over quarterly intervals for older adults enrolled in the PACE community-based long-term care program

BACKGROUND AND AIMS

Many frail older adults experience multiple changes in activities of daily living (ADL) functioning over the course of a year. Accurate predictions of ADL status over quarterly intervals may improve the precision of care planning for older adults who seek long-term care in the community. The study sought to develop and validate a model that predicts older adults' ADL status over quarterly intervals.

METHODS

The study included 3127 enrollees from 11 Program of All Inclusive Care for the Elderly (PACE) sites. Nurses assessed ADL status quarterly. Potential predictors included baseline assessment of age, sex, race, and living situation and quarterly assessments of prior functioning, co-morbidities, prior hospitalizations, and mental status.

RESULTS

Change in level of functioning occurred for 30% of quarterly observations. Predictors of functioning at the end of a quarter were prior ADL change, prior hospitalization, living with others, impaired mental status, cancer, dementia, coronary artery disease, congestive heart failure and chronic obstructive pulmonary disease. When the model was applied to the validation observations, 93% of predictions were within one level and 72% of the predictions were the same level of ADL functioning observed at the end of the quarter.

CONCLUSIONS

In a sample of community-living ADL-disabled older adults, changes in functional status over a quarter were common and associated with functional and health status at the beginning of the quarter. Further validation of the model may result in an index that helps clinicians better predict future ADL needs of community-living older adults who need long-term care.

Gender differences in functional status in middle and older age: are there any age variations?

OBJECTIVES

The present study examines gender differences in changes in functional status after age 50 and how such differences vary across different age groups.

METHODS

Data came from the Health and Retirement Study, involving up to six repeated observations of a national sample of Americans older than 50 years of age between 1995 and 2006. We employed hierarchical linear models with time-varying covariates in depicting temporal variations in functional status between men and women.

RESULTS

As a quadratic function, the worsening of functional status was more accelerated in terms of the intercept and rate of change among women and those in older age groups. In addition, gender differences in the level of functional impairment were more substantial in older persons than in younger individuals, although differences in the rate of change between men and women remained constant across age groups.

DISCUSSION

A life course perspective can lead to new insights regarding gender variations in health within the context of intrapersonal and interpersonal differences. Smaller gender differences in the level of functional impairment in the younger groups may reflect improvement of women's socioeconomic status, greater rate of increase in chronic diseases among men, and less debilitating effects of diseases.

The association between low vision and function

OBJECTIVE

This study considers the relationship between low vision and function, specifically exploring whether vision loss is differentially associated with activities of daily living (ADL) versus instrumental activities of daily living (IADL) disability.

METHODS

Guided by the World Health Organization's International Classification of Functioning, Disability, and Health framework, multinomial logistic regression analyses were performed for IADL and ADL on a sample of 9,115 adults aged 65 years and above from the 1998 Health and Retirement study.

RESULTS

The data supports the fact that ADL and IADL disabilities are associated with vision loss, and there is a differential relationship among functions, with IADLs being more challenging and requiring better visual abilities.

DISCUSSION

The findings provide evidence that ADL and IADLs require different skills and are associated differently depending on numerous variables. As the incidence of people living with vision loss is increasing to epidemic proportions due to an aging population, understanding the relationship between vision and participation in meaningful activities has important implications.

Dynamics of Frailty and ADL Dependence in a Five-Year Longitudinal Study of Octogenarians

Using a sample of octogenarians from the Swiss Interdisciplinary Longitudinal Study on the Oldest Old, the authors investigated the predictive validity of an expanded working definition of frailty based on deficiencies in mobility, memory, energy, and physical or sensory capacities and analyzed the resulting health transitions. The five domains were considered as predictors of the onset of dependence in activities of daily living (ADLs) and death using logistic multilevel and Cox survival regression models. Health transitions were studied with Markov chains. Deficiencies in memory, energy, and sensory capacities contributed to the prediction of the onset of ADL dependence and death in participants free of physical pains and mobility impairments. With two domains affected, frailty in very old persons indicated an increased risk of adverse outcomes. The study of transitions showed that ADL-independent frailty was a highly probable and relatively long transitional stage between robustness and ADL dependence.

Positive and negative social exchanges and disability in later life: an investigation of trajectories of change

OBJECTIVES

Various aspects of one's social ties are thought to influence the onset, progression, and course of disability in older adulthood. Although the longitudinal course of social ties and physical disability is likely to be marked by fluctuations over time and intraindividual variation, few studies have explored how patterns of change in positive and negative social exchanges relate to patterns of change in disability across time. The current study, therefore, examined the extent to which distinct longitudinal trajectories of positive and negative exchanges were associated with patterns of physical disability.

METHODS

We followed a sample of 482 community-dwelling older adults with little to no disability at baseline for 2 years.

RESULTS

Results identified multiple, distinct trajectory groups for positive and negative exchanges and disability. Latent class growth analyses revealed that individuals with chronically high or low positive exchanges were likely to experience low and increasing levels of disability. With respect to negative exchanges, individuals with moderately increasing negative exchanges showed patterns of increasing disability and disability remission, whereas chronically low or absent negative exchanges were associated with low and increasing levels of disability.

DISCUSSION

Findings highlight the importance of evaluating multiple trajectories of change in older adults' social exchanges and disability.

Eight-year change in functional ability among 70- to 95-year-olds

AIM

To describe stability and change in functional ability among non-institutionalized old people in relation to sex, age, and household composition during two subsequent four-year observation periods. The study describes stability and change in total functional ability as well as in specific daily activities.

METHODS

The study population included a random sample of non-institutionalized 70+-year-olds studied in 1986 with follow-up in 1990 and 1995. The number of participants in the three surveys were 1,231 (participation rate 67%), 911 (90% of 1,008 survivors), and 542 (77% of 706 survivors). Functional ability was measured at all three surveys. There is a considerable health selection from survey 1 to 2 to 3 because of a high mortality among participants with poor health.

RESULTS

The proportions with unchanged, improved, and deteriorated functional ability were 51%, 13%, and 37% during the first four years and 50%, 9%, and 42% during the following four years. These changes were not related to age and sex. Major variations were seen with regard to change in individual daily activities with most deterioration in mobility and the more outgoing IADL activities (Instrumental Activities of Daily Living). Relatively large proportions of elderly people demonstrated at the same time improvements in some functions and deterioration in others.

CONCLUSIONS

A notable minority of the population improved in functional ability and a large proportion was stable over time. These observations suggest a potential for health promotion among elderly persons, which up to now has been more or less neglected in health policy.

The epidemiology of arm and hand swelling in premenopausal breast cancer survivors

BACKGROUND

Breast cancer survivors suffer from lymphedema of the arm and/or hand. Accurate estimates of the incidence and prevalence of lymphedema are lacking, as are the effects of this condition on overall quality of life.

METHODS

Six hundred twenty-two breast cancer survivors (age, <or=45 years at diagnosis) were followed with semiannual questionnaires for 36 months after surgery to determine the incidence of lymphedema, prevalence of persistent swelling, factors associated with each, and quality of life.

RESULTS

Of those contacted and eligible for the study, 93% agreed to participate. Fifty-four percent reported arm or hand swelling by 36 months after surgery, with 32% reporting persistent swelling. Swelling was reported to occur in the upper arm (43%), the hand only (34%), and both arm and hand (22%). Factors associated with an increased risk of developing swelling included having a greater number of lymph nodes removed [hazards ratio (HR), 1.02; P < 0.01], receiving chemotherapy (HR, 1.76; P = 0.02), being obese (HR, 1.51 versus normal weight; P = 0.01), and being married (HR, 1.36; P = 0.05). Factors associated with persistent swelling were having more lymph nodes removed (odds ratio, 1.03; P = 0.01) and being obese (odds ratio, 2.24 versus normal weight; P < 0.01). Women reporting swelling had significantly lower quality of life as measured by the functional assessment of cancer therapy-breast total score and the SF-12 physical and mental health subscales (P < 0.01 for each).

CONCLUSIONS

Lymphedema occurs among a substantial proportion of young breast cancer survivors. Weight management may be a potential intervention for those at greatest risk of lymphedema to maintain optimal health-related quality of life among survivors.

Educational differences in the dynamics of disability incidence, recovery and mortality: Findings from the MRC Cognitive Function and Ageing Study (MRC CFAS)

BACKGROUND

This study aims to establish the extent of educational differences in the disability transitions of incidence, recovery and mortality in people aged 65 years and over, whether these can be explained by differentials in disease burden and their relative contribution to educational differences in prevalence and disability-free life expectancy (DFLE).

METHODS

A stratified random sample of 13 004 participants in five areas in England and Wales were interviewed in 1991-94 and followed up at 2, 6 (one centre only) and 10 years. Two levels of disability were analysed: mobility difficulty and activities of daily living (ADL) disability. We fitted logistic regression models to model educational differences in disability prevalence, incidence, recovery and mortality transitions. DFLE was calculated to assess the combined effect of the dynamic transitions.

RESULTS

Those with < or =9 years education had higher ADL and mobility disability prevalence and higher incidence and lower recovery of mobility disability. Differences in disability incidence remained after adjustment for comorbidity. Women with the lowest education had shorter life expectancies (1.7 years less at the age of 65 years) than the most educated and had even shorter DFLE (1.9 years free of ADL disability and 2.8 years free of mobility difficulty at the age of 65 years).

CONCLUSIONS

Differentials in education continue to contribute to prevalence of disability at ages beyond 65 years in both men and women and independently of diseases. These appear to be driven predominantly by differentials in disability incidence that also compound to produce greater differentials in DFLE between education groups than in total years lived.

The level and time course of disability: trajectories of disability in adults and young elderly

OBJECTIVES

The objectives of this study were: (i) to identify trajectories in the level and time course of disability, (ii) to determine the relative frequency of each trajectory, and (iii) to assess the relationship of these trajectories with age, sex and the presence of four chronic diseases (asthma/chronic obstructive pulmonary disease (COPD), heart disease, severe low back complaints and diabetes mellitus).

METHODS

We used six measurements of disability and information on mortality from a longitudinal study in Dutch persons aged 15-74. We used cluster analyses to group persons with similar levels and time courses of disability into disability trajectories. Deaths were classified into a separate trajectory. Multinomial regression was used to assess the relationship of the trajectories with age, sex and the four chronic diseases. Information on disability in the last year(s) prior to death was used to examine disability prior to death.

RESULTS

Nine trajectories of disability were identified, while all deaths were classified into a separate trajectory; 74% was entirely non-disabled. The size of the other trajectories varied from 10% (permanently mildly disabled) to 0.5% (severely disabled with large increase in disability). Significant associations were found with age and, correcting for age and sex, with asthma/COPD, heart disease and low back complaints, but not with diabetes. The ORs were generally highest for trajectories characterized by severe disability, although disease-specific associations were also found. Among the deaths, 41% of the trajectories were associated with disability prior to death. Disability prior to death was more prevalent among persons with heart disease, back complaints, and asthma/COPD.

CONCLUSIONS

These findings suggest that disability is a dynamic process, and that important differences exist within the 'disabled' population. This is important for assessing the need for care and shows the limitations of modeling disability change based on two measurements only.

The measurement of change in functional ability: Dealing with attrition and the floor/ceiling effect

The purpose was to describe four-year change in functional ability among older persons and the relationship to sex, age, and other background factors. The baseline study, performed in 1986, is based on a random sample of older persons (n=1261). Follow-up data were collected four-years later (n=912). The analyses of change in functional ability were based on the assumption that the categories reflected an underlying latent continuous dimension. The change in functional ability, DeltaFA, was calculated by a logistic model for paired observations and applied in parallel analyses with and without inclusion of the dead to deal with the attrition problem. Fifty percent had no change in functional ability, 37% had declined and 13% improved. Models including the dead showed more functional decline with increasing age but this was not the case when the dead were excluded. Functional change was not related to sex, functional ability at baseline, relative wealth, social network, self-rated health, and life-satisfaction. Inclusion of the dead in statistical models for the study of change in functional ability reduced the attrition problem. A logistic model for paired observations of functional ability at two points in time reduced the problem related to the floor/ceiling problem.

The effect of prior disability history on subsequent functional transitions

BACKGROUND

Many older persons experience multiple transitions between states of disability and independence, but little is known about the effect of prior disability history on subsequent functional transitions. Our objective was to determine the effect of prior disability on subsequent transitions between no disability, mild disability, severe disability, and death.

METHODS

For 60 months, 754 persons aged 70 or older underwent monthly assessments of disability in basic activities of daily living. We used a multistate extension of the proportional hazards model to determine the effects of amount, defined as cumulative duration, and distribution, defined as number of episodes, of prior disability on subsequent functional transitions, adjusted for age, gender, cognitive status, timed gait, and habitual physical activity.

RESULTS

For each additional month of prior disability, participants were more likely to make transitions representing new or worsening disability and were less likely to make transitions from disability to independence or from severe disability to death. Adjusting for the cumulative duration of prior disability, more episodes of prior disability were associated with a higher likelihood of most transitions, representing both increasing and decreasing disability, but had no effect on transitions to death.

CONCLUSIONS

Both the amount and distribution of prior disability are important determinants of the likelihood of subsequent functional transitions. Analytic methods that account for prior disability history should be used in studies of functional transitions, and new measures of disability burden are needed that incorporate distribution as well as amount of disability.

The impact of cognitive functioning on mortality and the development of functional disability in older adults with diabetes: the second longitudinal study on aging

Background

For older adults without diabetes, cognitive functioning has been implicated as a predictor of death and functional disability for older adults and those with mild to severe cognitive impairment. However, little is known about the relationship between cognition functioning on mortality and the development of functional disability in late life for persons with diabetes. We examined the relative contribution of cognitive functioning to mortality and functional disability over a 2-year period in a sample of nationally representative older US adults with diabetes who were free from cognitive impairment through secondary data analyses of the Second Longitudinal Study of Aging (LSOA II).

Methods

Participants included 559 US adults (232 males and 327 females) ≥ 70 years old who had diabetes and who were free from cognitive impairment were examined using an adapted Telephone Interview of Cognitive Status (TICS), Activities of Daily Living (ADL), and Instrumental Activities of Daily Living (IADL).

Results

Multivariate logistic regression was conducted to investigate the independent contribution of cognitive functioning to three mutually exclusive outcomes of death and two measures of functional disability status. The covariates included in the model were participants' sex, age, race, marital status, educational level, duration of diabetes, cardiovascular disease (CVD) status, and self-rated health. Persons with diabetes who had the lowest levels of cognitive functioning relative to the highest level of cognitive functioning had a greater odds of dying (AOR = 0.80, 95% CI = 0.67–0.96) or becoming disabled (AOR = 0.87, 95% CI = 0.78–0.97) compared to those people who were disability free.

Conclusion

Older adults with diabetes and low normal levels of cognition, yet within normal ranges, were approximately 20% more likely to die and 13% more likely to become disabled than those with higher levels of cognitive functioning over a 2-year period. Brief screening measures of cognitive functioning could be used to identify older adults with diabetes who are at increased risk for mortality and functional disability, as well as those who may benefit from interventions to prevent or minimize further disablement and declines in cognitive functioning.

Home is where their health is: rethinking perspectives of informal and formal care by older rural Appalachian women who live alone

The purposes of this qualitative descriptive study were to describe the perceptions of rural, older Appalachian women who live alone regarding systems of informal and formal care and to understand if traditional cultural norms influence attitudes and decisions to access these two systems. Older Appalachian women in this study defined themselves and their health in terms of their homes and as women who care for themselves informally and value independence and privacy. Five major themes emerged from the data for informal care, and three related to formal care or use of it. The findings support a reconceptualization of informal and formal care and point out reasons why these women chose to use or not use these two systems of care. Furthermore, they reveal how changes in the formal care system could support health promotion and prevention strategies grounded in everyday ways of maintaining health within the context of home.

Cognitive functioning as a predictor of functional disability in later life

OBJECTIVE

The contribution of cognitive functioning on multiple levels of functional disability and mortality over two years as well as individual activities of daily living (ADLs) and instrumental activities of daily living (IADLs) tasks, in a sample of older U.S. adults was examined.

METHODS

A total of 4,077 U.S. adults (1,493 males and 2,584 females) aged > or =70 years (mean = 76.35 years) from the Second Longitudinal Study of Aging (1997/1998-1999/2000) were examined using an adapted Telephone Interview of Cognitive Status (TICS), ADLs, and IADLs.

RESULTS

Multivariate logistic regression investigated cognition as a predictor of five mutually exclusive levels of functional disability. People with the lowest level of cognition had greater odds of mortality at follow-up (adjusted odds ratio [AOR] = 2.86, 95% confidence interval [CI] = 1.94-4.20), ADL and IADL disability (AOR = 1.58, 95% CI = 1.15-2.16), ADL disability (AOR = 1.83, 95% CI = 1.27-2.64), or IADL disability (AOR = 1.22, 95% CI = 0.86-1.71) than those who were disability-free. Cognitive functioning was not predictive of individual ADL tasks but was predictive of the IADL tasks of preparing meals, shopping for groceries, managing money, telephone use, light housework, and medications but not heavy housework.

CONCLUSION

Persons with lower levels of cognitive functioning were more likely to die or become disabled than those with higher levels of cognition. Changes in cognitive functioning might serve as an early indicator of neurologic and medical factors.

Effects of body composition and leisure-time physical activity on transitions in physical functioning in the elderly

Physical activity and body composition were examined with respect to variation in functional limitation over a 6-year period (four surveys conducted between 1994 and 2000) based on a cohort of 1,655 community-dwelling older women and men living in Sonoma, California. Measures of functional limitation and physical activity were based on standard self-report questions. Measures of body composition (lean mass, fat mass) were estimated from bioelectric impedance by using population-specific prediction equations derived from dual-energy x-ray absorptiometry. For women, a one-unit gain in lean mass:fat mass ratio reduced the report of limitation at all surveys 65.5% (95% confidence interval: 21.8, 87.4). A similar reduction was not observed for men; however, there was a 3% increase in the report of no limitation at any survey. The effect of high levels of physical activity reduced new functional limitation that occurred at the last survey by 36.8% (95% confidence interval: 0.0, 92.2) for men and 52.7% (95% confidence interval: 13.5, 91.9) for women. In summary, higher levels of physical activity appeared to reduce the risk of future functional limitation conditional on the level of functioning established early in the disablement process by lean mass:fat mass ratio.

Nondisease factors affected trajectories of disability in a prospective study

OBJECTIVE

To examine nondisease factors, including sociodemographic variables, health behaviors and psychosocial factors as determinants of trajectories of disability.

STUDY DESIGN AND SETTING

We used a classification of 10 trajectories of disability based on a multiround prospective study design; nine trajectories grouped survivors with a similar level and time course of disability, one included all deaths. Multinomial logistic regression was used to assess associations between these trajectories and a wide range of nondisease factors.

RESULTS

Correcting for age, sex, and four chronic diseases, we found that sociodemographic factors (education and income), health behaviors (leisure-time physical activity and BMI), and psychosocial factors (locus of control, neuroticism, and active problem focusing) were significantly associated with the trajectories of disability. Moreover, our results pointed to factors associated with disability trajectories that were characterized by sudden increase (external locus of control and, to a lesser extent, BMI), strong fluctuations (neuroticism, BMI, external locus of control), or high severity (leisure-time physical inactivity) of disability.

CONCLUSION

A wide range of nondisease factors is associated with the trajectories of disability. Preventing obesity, developing a more internal locus of control, and increasing physical activity could contribute to preventing trajectories characterized by rapid decline, large fluctuations or severe disability. Understanding the role of these factors should receive high priority.

The effects of social networks on disability in older Australians

OBJECTIVE

To investigate the effects of total social networks and specific social networks with children, relatives, friends, and confidants on disability in mobility and Nagi functional tasks.

METHODS

Six waves of data from the Australian Longitudinal Study of Ageing were used. Data came from 1,477 participants aged 70 years or older. The effects of total social networks and those with children, relatives, friends, and confidants on transitions in disability status were analyzed using binary and multinomial logistic regression.

RESULTS

After controlling for a range of health, environmental, and personal factors, social networks with relatives were protective against developing mobility disability (OR = 0.89; 95% CI = 0.79 to 1.00) and Nagi disability (OR = 0.85; 95% CI = 0.74 to 0.96). Other social subnetworks did not have a consistent effect on the development of disability.

DISCUSSION

The effects of social relationships extend beyond disability in activities of daily living. Networks with relatives protect against disability in mobility and Nagi tasks.