The Journal of Nutrition, Health & Aging© Volume 10, Number 1, 2006

THE JOURNAL OF NUTRITION, HEALTH & AGING©

NUTRITIONAL, FUNCTIONAL AND PSYCHOSOCIAL CORRELATES OF DISABILITY AMONG OLDER ADULTS C.S.J. JOHNSON1,2, A. MAHON1, W. McLEOD3 1. School of Nutrition & Dietetics, Acadia University, Wolfville, NS, 2. Canadian Centre for Activity and Aging, University of Western Ontario (UWO), London, ON, 3. School of Recreation Management & Kinesiology, Acadia University, Wolfville, NS, CANADA. C. Shanthi Jacob Johnson, PhD, PDt (corresponding author), Associate Professor, School of Nutrition and Dietetics, Acadia University, Wolfville, Nova Scotia B4P 2R6, Telephone: (902) 585 - 1204, Fax: (902) 585 - 1095, Email: [email protected]

Abstract: Purpose. The purpose of the present study was to examine the nutritional, functional and psychosocial correlates of disability among 54 older adults aged 65 years of age or older. Methods. Using validated questionnaires and tests, nutritional risk (Mini-Nutritional Assessment), functional capacity (mobility, balance, endurance, grip strength and lower extremity strength), the psychosocial factors (life satisfaction, depression, and social support) and level of disability of the participants were examined. Results. The study showed that functional mobility was the strongest correlate of disability, even after controlling for age, gender and residential living status (p < .05). Life satisfaction and nutrition risk had marginal significance as being related to disability. Conclusion. The results of the present study have implications for the development of evidence-based health promotion interventions for older adults. Key words: Disability, nutrition, function, psychosocial factors.

Older adults represent one of the fastest growing population groups in Canada, increasing twice as fast as the overall population since the early 1980s (1). Currently, 3.7 million Canadians are over the age of 65 years, representing 12% of the Canadian population (1-2). Similar trends have been reported for other developed nations around the world (3). Accompanying increases in population size is increased average life expectancy, which has drastically risen since the turn of the century (4). With increasing age, there is a concern about decreasing functional ability, increasing disability and dependence (5). Loss of independence is considered one of the three greatest fears of older adults, together with poor health and inadequate income (6). Decreased functional ability and increased level of disability prevents older adults from living independently in the community, thereby contributing to costly long-term care (7). Reducing the period of morbidity in older adults is critical to improving quality of life and controlling health care costs. Therefore, an important endpoint for research should be the reduction in the level of disability (8). Research has shown that as much as 50% of the age-related decline in physical function leading to disability and dependence is preventable through early discovery and suitable adjustments in health behaviours (3, 9-10). Variables such as functional capacity, nutritional risk, and the psychosocial factors of life satisfaction, social support and depression have an impact on the level of disability among older adults. Several investigations of regular physical activity among older adults have shown that increased activity level is positively related to the reduction in disability among community-dwelling and long-term care older adult populations (7,11). Recent research has shown that a higher level of functional limitation in daily living among older adults is related to less than optimal nutritional status (12-13). In addition, psychosocial aspects of

health and well-being, namely life satisfaction, depression, and social support, affect the quality of life of older adults, which includes their ability to remain functionally independent (1517). Although the association between these individual factors on disability have been studied, there is paucity of research examining these factors as a collective unit within a study, and therefore, the degree to which each relates to disability remains unknown. Through the identification of the modifiable variables that are precursors or explanatory correlates of disability, a foundation for the development of evidence-based health promotion strategies could be established. Thus, the purpose of this study was to examine the relationship between physical, nutritional, and psychosocial factors and the level of disability among older adults living in the community and in long-term care facilities. Methods Participants In the present study, 54 participants over 65 years of age, 25 males and 29 females, were selected from a small, predominantly rural population. Of the total sample, 26 participants were living in their own homes in the community and 28 were residing in nursing homes or similar long-term care facilities. Both groups were included to ensure a wide cross section of functional levels among the selected participants. Also, it was deemed important to include a diverse sample in order to increase the generalizability of the findings. The sample comprised approximately 50% women in both groups. Participants were recruited through advertisements in the local newspaper, community organizations (e.g., grocery stores,

45

The Journal of Nutrition, Health & Aging© Volume 10, Number 1, 2006

NUTRITIONAL, FUNCTIONAL AND PSYCHOSOCIAL CORRELATES OF DISABILITY veterans community hall) and other senior living facilities. Inclusion criteria included an adult over the age of 65 years. Exclusion criteria included the self reported diagnosis of unstable respiratory, metabolic, or cardiovascular diseases, valvular or rhythm abnormalities, stroke of any etiology, and those who were non-ambulatory with or without the aid of an assistive device. Those participants who were unable to read a letter of information and provide a signed consent to participate in the study were not included. Screened-to-enrollment ratio was 100%. The authors’ institutional Research Ethics Board approved the study. One of the co-authors along with a trained research assistant administered the questionnaires and physical tests. Measures Background Questionnaire Information was gathered on the participant’s background, including age, lifestyle factors, socio-economic status, history of disease, and current perceived health status. Disability Level of disability was assessed using Katz’ (1963) Index of Independence in Activities of Daily Living (ADL) Scale and Lawton and Brody’s (1969) Instrumental Activities of Daily Living (IADL) Scale (18-19). Both scales have been widely used in the literature (20-22). The index of ADL and IADL were scored according to three levels as defined by Mehdizadeh, Kunkel and Bailer (2000) (23). Levels of disability were categorized as severe (dependence in two or more selected ADL items); moderate (dependence in at least one ADL item or at least two IADL items); and little or no disability (independence in all ADL items or dependence in one of a selected group of IADL items). Mobility The Timed-Up-and-Go (TUG) test, which is a measure of functional mobility, assessed the time it took the participant to rise from a chair, walk at a comfortable pace three metres away, turn around and return to the seated position in the chair (24). Podsiadlo & Richardson (1991) report that the TUG test is reliable for measuring the functional mobility of older adults. Endurance Functional endurance was assessed using the six-minute walk test, whereby the participant walked as far as possible for the duration of six minutes, with the total distance walked in the specified time recorded (25). Interrater reliability of this measure was 0.92 and the reliability was not influenced by the presence of cognitive impairments (26). Balance Dynamic balance was assessed using the Functional Reach (FR) test, where participants were asked to reach as far forward 46

along a wall as possible while standing (27). The greatest difference between the individual’s arm length and maximal reach among three trials was recorded. The FR test has been widely used as a measure of dynamic balance for older adults (28). Grip Strength Individual arm strength was assessed using the Lafayette hand dynamometer (29). Hand grip dynanometry has been shown to be a valid indication of upper extremity strength when tested on home care patients and it significantly correlated with upper manual muscle test scores of both healthy and home care older adults (29-31). Lower Extremity Strength All participants performed the Sit-to-Stand test, where they were instructed to rise from a chair to a fully erect position and then return to the seated position. The fastest of three trials was recorded, followed by the timing of five consecutive sit-tostands. Franchignoni, Tesio, Martino, and Ricupero (1998) have found the STS test to have interrater and test-retest reliability scores of 0.98 and 0.93, respectively (32). Nutritional Risk The Mini-Nutritional Assessment (MNA) was used to identify those individuals at risk of malnutrition (13). This 18item screening tool consisted of four components – anthropometric measures (e.g., mid-arm and calf circumferences and weight loss), general assessment (e.g., medication use and neurological psychological problems), dietary indicators (number of meals and food consumption), and self-assessment (self perception and peer comparison) and each item was answered using either a yes or no response with a total assessment score out of 30 points. Lower scores on the MNA indicated greater nutritional risk. The MNA has been cross-validated in older individuals from the healthy elderly to the very frail (13, 33). Life Satisfaction Life satisfaction was measured using a 13-item Life Satisfaction Index Form-Z (34). Statements were graded out of a potential score of 26 points, with higher scores denoting better life satisfaction. The LSI-Z is a self-report five-point scale measuring the degree to which you agree with the statements provided. The reliability of this scale ranges from 0.77 to 0.79 in the literature, indicating a high degree of internal consistency (34-36). Depression The Geriatric Depression Scale (GDS) was used to assess individual anxiety and depression-related symptoms (37). The scale contains 15 items and is scored using either a yes or no response scale. Scores greater than five points indicate probable depression. The GDS has been validated with a wide

The Journal of Nutrition, Health & Aging© Volume 10, Number 1, 2006

THE JOURNAL OF NUTRITION, HEALTH & AGING© range of populations and it has a high degree of reliability (a = 0.94) reported in the literature (38).

normality were used to examine the distribution of test results for the various measures. The Mann-Whitney test was used to compare the population medians of selected physical measures. Binary stepwise regression analysis with the forward selection procedure was used to assess the relationship between disability and potential correlates—nutritional risk, functional capacity, life satisfaction, depression, and social support. This model was adjusted for age, gender and residential status. The significance level was set at (p=good) Number of Medications (mean ± SD) Number of Health Problems (mean ± SD)

Community-dwelling

Long-term care

p-value

75.5 ± 6.8 50.0

85.6 ± 7.3 53.6

0.000 1.000 0.165

4.6 65.4

60.7 39.3

57.7 38.5 3.8

10.7 60.7 28.6

88.5 11.5 92.3 92.3 92.3 1.9 ± 1.0 4.2 ± 1.9

50.0 50.0 75.0 89.3 75.0 6.5 ± 3.6 5.4 ± 2.6

0.000

0.017

47

0.144 0.612 0.226 0.001 0.075

The Journal of Nutrition, Health & Aging© Volume 10, Number 1, 2006

NUTRITIONAL, FUNCTIONAL AND PSYCHOSOCIAL CORRELATES OF DISABILITY community-dwelling and long-term care participants in mean scores on the life satisfaction, depression, and social support measures. Table 2 Comparison of ADL and IADL Scores among Communitydwelling and Long-term Care Participants Based on Mehdizadeh, Kunkel, and Bailer’s Classification of Disability (23) Living Status Disability

Community-dwelling

Long-term care

little or none moderate severe

53.8 46.2 0.0

0.0 57.1 42.9

age, gender and residential living status, the measure of functional mobility based on the Timed-Up-and-Go (TUG) test was shown to be a significant correlate of disability (p-value = 0.006). Based on observation of the model coefficients, a higher score on the TUG test was related to lower levels of disability. Looking at the significance of individual variables after accounting for gender, age, and residential status, the measure of life satisfaction (p-value = 0.069) and the measure of nutritional risk (p-value = 0.077) were marginally significant. Table 4 shows the correlates and their corresponding p-values following stepwise regression. Discussion The purpose of the present study was to explore the correlates of disability among older adults living in the community and in long-term care facilities. Not surprisingly, older adults living in the community groups were significantly different in levels of disability than those living in long-term care facilities. Individuals in the community were capable of performing social and household tasks; however, only a small percentage of individuals in long-term care were independently able to perform basic self-care activities such as bathing and continence. By definition, people are placed in long-term care facilities when they cannot safely care for themselves or be

Correlates of disability based on a multiplicity of factors (nutritional risk, functional capacity, life satisfaction, depression, and social support) were assessed using regression equations. The variables most highly associated with disability were determined using binary logistic stepwise regression with the forward selection procedure. The “severe” and “moderate” classifications of disability by Mehdizadeh, et al. (23) were combined to accommodate a binary scale, with the “little or none” classification as the other category. After controlling for Table 3 Comparison of Scores for the Nutritional, Functional and Psychosocial Measures Among Community-dwelling and Long-term Care Participants Living Status Measures Nutritional Risk Score (MNA) Functional Mobility (sec.) TUG test (mean ± SD) Functional Endurance (m) 6-min walk test (mean ± SD) Dynamic Balance (sec.) FR test (mean ± SD) Grip Strength (kg) Dynamometer (mean ± SD) Lower Extremity Strength (sec.) STS test (1 repetition) STS test (5 repetitions) Life Satisfaction Index-Z (mean ± SD) Geriatric Depression Scale (%) Scores < 5 points Scores > 5 points Lubben Social Network Scale (mean ± SD)

Community-dwelling

Long-term care

p-value

28.1 ± 2.1

25.0 ± 2.8

0.000

10.2 ± 2.4

36.2 ± 35.3

0.001

461.9 ± 124.9

164.7 ± 91.0

0.000

37.3 ± 6.7

20.8 ± 7.7

0.000

29.6 ± 9.5

17.2 ± 6.3

0.000

3.3 ± 0.6 15.9 ± 3.8 21.5 ± 2.8

7.3 ± 5.7 29.8 ± 12.3 14.9 ± 5.1

0.001 0.000 0.000

100.0 0.0 33.8 ± 7.7

61.4 35.7 24.5 ± 7.9

0.001

48

0.000

The Journal of Nutrition, Health & Aging© Volume 10, Number 1, 2006

THE JOURNAL OF NUTRITION, HEALTH & AGING© cared for by others. The results of the present study are consistent with other studies reported in the literature. Sonn and Asberg showed that older adults who live independently had better overall performance on measures of ADL than those who lived dependently (43). Measures of IADL have also been shown to be predictors of functional decline and nursing home placement (44). Table 4 P-values of the Correlates Following Stepwise Logistic Regression with Forward Selection Procedure Based on Mehdizadeh, Kunkel, and Bailer’s Classification of Disability (23) Variables Variables in the Equation Functional mobility (TUG test) Variables Not in the Equation Nutritional risk (MNA) Arm strength (dynamometer) Balance measure (FR test) Lower extremity strength (1-STS test) Lower extremity strength (5-STS test) Functional endurance (Six-minute walk) Life satisfaction measure (LSI-Z) Depression measure (GDS) Social support measure (LSNS)

p-value

0.006 0.077 0.153 0.199 0.962 0.514 0.905 0.069 0.549 0.685

As stated earlier, several individual factors including nutritional risk, functional capacity, and psychosocial factors such as life satisfaction, depression and social support have been related to disability. Higher levels of dependence among older adults are related to higher risk for malnutrition, lower scores on physical function and poorer psychosocial health (78, 13, 15). However, in the present multifactorial analysis, the most significant variable associated with disability, after controlling for age, gender, and residential status was level of mobility based on the TUG test. Functional mobility has been found to related to the level of disability in older adult populations (45-46). Out of the factors examined, functional mobility is most closely related to measures of ADL and IADL. Guo, Matousek, Sonn, Sundh, and Steen found that IADL dependence was associated with both self-reported mobility difficulties and poor performance in an objective measure of mobility (47). In addition, mobility is included among ADL and IADL as one of three selfmaintenance components for remaining functionally independent in older adulthood (48). Blocker points out that maintenance of mobility among the aging population is critical to the prevention of unnecessary nursing home placement (9). Given the strong relationship between mobility and disability, strategies to improve the level of mobility among older adults are warranted. In particular, exercise and restorative care

interventions should be promoted in the community and in long-term care institutions to improve functional mobility. Life satisfaction and nutritional risk were shown to be marginally related to disability, after controlling for gender, age and residential status. Although life satisfaction and nutritional risk are related to disability, the level of impact might be through its influence on functional mobility. Nutritional risk and life satisfaction might influence functional mobility, which in turn, could influence the level of disability. A limitation of the present study is the choice of a cross sectional design. As such, causality on the relationship between functional mobility, nutritional risk, perceived life satisfaction and disability cannot be inferred. The diverse sample could be perceived as a limitation of the present study. It is hoped that the results of the present study will serve as a catalyst for further studies examining the issue of disability among older adults. Specifically, the implementation of a longitudinal analysis of the factors related to disability is recommended. In summary, the two residential status groups were significantly different in age, financial status, self-perceived health and medication use, but similar in gender, education level and number of chronic health problems. The most important correlate of disability, after controlling for age, gender, and residential living status, was functional mobility, with the measures of life satisfaction and nutritional risk being marginally related. In addition, nutritional risk and psychosocial issues, especially life satisfaction, should be addressed in health promotion programs targeting older adults. References 1.

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