Activity limitations and Risk Factors in Old Age

This study was set out to investigate the possible causes for limited movement in old age. Majority of the population were younger and stayed with their family. Follow-up of our included patients for two years revealed that Age at the baseline, level of education, number of medications or polypharmacy, walking speed, dementia and the physical component of the self-reported health survey (SF-12) significantly associated with activity limitations in self-care (KATZ) after two years in the multivariate analysis.

However, when adding the cognitive disability, these variables became insignificant. Our cohort included 31.4% had activity limitation in 5TCHS. After two years, the multivariate analysis revealed that age at the baseline, level of education, DBI, walking speed, grip strength and the PCS of SF-12 were significantly associated with activity limitations in the 5TCHS. Furthermore, in our cohort, only 37.4% had limited walking at the baseline. After two years, age at the baseline, polypharmacy, frequency of falls, spoken language, MCS and PCS of SF-12 were significantly associated with activity limitations in walking speed in the multivariate analysis.

Our study results are consistent with a study of Danish cohort of 1187 elderly persons [28]. Laan et al. used KATZ-15 scale and ADL scale. Sociodemographic factors were significant in the univariate analysis and were associated with less independence. However, in the multivariate analysis, living with partner, socioeconomic standard, level of education and having children failed to be significant. Moreover, they assessed the comorbid conditions including stroke, arthritis, diabetes, osteoporosis and dementia which were found to have more influence on independence than sociodemographic factors. Another difference from our study is that we have followed our patients for two years while Laan et al. was a cross sectional study [28]. It was also consistent with another study in Australia that identified the same risk factors for disability [31].

Other studies found that age is important factor for independence. Laan et al. found a disability prevalence rate of 1,03 in women and 1.07 in men for every year increase in age [28]. Moreover, Nascimento et al. found a prevalence rate of 2.6 in elderly over 85 compared to those in their 60s [27]. Aging and low score in Short Physical Performance Battery (SPPB) was associated with low mobility in elderly [48].

Furthermore, prevalence of dependence in ADL increases from 7% among people aged 65-74 to 24% among those who are more than 84 years old [49]. In addition, functional dependence is very common among very old adults (age 75 or more), and that dementia and cognitive impairment explain a large proportion of current and future dependence [50]. This can be explained that After 60 years of age, muscle strength reduces by 3.5% each year and After 63 years of age, gait speed decreases by 0.2% then 1.6% [29].

Our study was only performed in men; it was found that gender plays an important role for determining the risk of disability. It was found that men was mainly affected by disorders of central nervous system while women were mainly affected by sedentary lifestyle and disorders affecting osteoarticular system [29].

In our study, 52.1% of elderly had taken 4 or less drugs. Laan et al. found that the more medication the elderly take, the worse the disability which was consistent with our study [28]. They explained that this significant effect is mainly due to underlying somatic disorders [28].

Furthermore, Alexandre et al. had found that higher cognitive function and strong hand grip had better outcome and more independence. They also found that other diseases like stroke, dementia and slowness of sit and stand test were associated with more disability which is consistent with the results of our study [29].

A similar Australian study was conducted on 12422 elderly women. In this study, they assessed the alcohol drinking, smoking and marital status and their association with mortality during follow-up. Surprisingly, they found that non-alcohol drinkers, lower physical activity were more prone to death [51]. Falls were assessed in our study as one of the causes of the disability. However, a study found that the elderly had tendency not to recall their falls within specific periods reaching up to 3 -12 months after the fall. This impose inaccuracy regarding this covariate [52].

Lower visual acuity was associated with more disability. This can be explained that the lower visual was associated with more fall, hence, more comorbidity and disability [53]. The cognitive impairment was found to cause decline in the ADL independence as suggested by Mehta et al. in this study, they followed up the patients for two years. They had found that in patients with independence, both cognitive impairment and risk factors were a robust predictor of decline. Meanwhile, in patients with ADL dependence, only cognitive impairment was risk factor for more decline [25].

In this study, we have used KATZ index for assessment of the independence in elderly adults [16]. It assesses the need for help for daily activities e.g. going to the toilet. Despite its use in many studies, in a cohort study of Canadian elderly respondents, the KATZ-6 scale underestimated the limitation of movement [17]. However, another study in Turkish elderly respondents found that the KATZ-15 scale was better and had high consistency and valid for detection of the limitation of movement in elderly [54]. Another study in a Danish elderly cohort also used KATZ scale for assessing the quality of life and its relation to the hospitalization, admission to a nursing home, admission to a home for the aged and death within one year of follow-up.

They found that it accurately predicts the unfavorable outcome and it has a strong association with quality of life measures [18]. Surprisingly, a study found that KATZ scale was only sensitive to specific somatic disorder like asthma and COPD and other diseases scored higher. They illustrated that these disorders hinder the elderly from walking or cleaning [18].

Another scale that we used was 5TCHS; this scale is used to assess the fall risk and physical dysfunction in elderly. In a study by Yamada et al., they found that sit to stand tests scores were significant predictors for functional disability and risk for fall. However, they suggested that repetition times are more robust for determination of degree of dysfunction [20].

Despite these results, there are many biases that can affect the results of the test. Shamay et al. found that gender, the height of the chair and arm position may affect the test results [21, 55]. Another study signified that it tests the lower extremities strength, but it should be interpreted in the light of age and comorbidities [20].

Moreover, in this study, we used walking speed as one of the assessment tools for ADL independence. Graham et al used the walking speed threshold for classifying the walking independence in hospitalized elderly [24]. Another study implied that gait speed was a significant predictor of elderly mortality [19]. These data signify that our scales were considered enough for assessment of functional disorders in elderly.

The identification of the possible risk factors for limited movement and functional disability in elderly would help further studies to prevent or enhance quality of life in elderly [56].

In conclusion, we believe that for healthy aging, we should identify the risk factors for functional disability and independence in elderly.