INTRODUCTION
One way to compensate for the decline in physical function is to use walking aids. Systematic reviews have demonstrated that older adults can use walking aids to enable activity and participation in various domains.1) Moreover, walking aids not only improve mobility but also support active participation in social life.2) This study is an important statement for people involved in rehabilitation, supporting the idea that we should not only focus on functional improvements but also prescribe appropriate walking aids to improve physical function and encourage activity and participation. Furthermore, the use of walking aids has been reported to be beneficial in reducing the demand for attention and increasing stability.3) However, it has also been found to be associated with an increased risk of falls.4,5) In addition, based on the fact that approximately 50% of the body weight can be unloaded with the use of walking aids,6) in can be inferred that excessive use of walking aids may be a factor in the decline of physical function. Some older adults hesitate to use walking aids due to social stigma,7) which may reduce their outdoor activities and overall mobility. Therefore, walking aids should be appropriately prescribed after assessing capacity.
The use of walking aids has been found to be associated with a fear of falling and reduced walking ability.8) Studies conducted on older adults in long-term care have also demonstrated that fear of falling and balance ability are associated with the use of walking aids9) and that older adults who use walking aids experience falling.10) Furthermore, age and cognitive impairment have been identified as predictors of the type of walking aid used,11) and a diverse range of factors are relevant. Our group has systematically conducted studies on toe muscle strength and reported that it is associated with gait speed and stand-up movements.12,13) We hypothesize that not only functions associated with the use of walking aids but also toe muscle strength is relevant.
Many previous studies have focused on a single variable, such as physical or cognitive function, and very few studies have investigated more strongly associated factors with the presence or absence of cane use. In addition, no studies have examined the association between toe muscle strength and the presence or absence of cane use. Therefore, this study aimed to (1) examine the factors associated with the presence or absence of cane use in older adults from a comprehensive set of assessed variables and identify factors with stronger association as well as (2) to determine whether toe muscle strength, which we have systematically studied, is relevant. The results of this study will facilitate the prescription of walking aids to older adults, which in turn will contribute to the improvement of activities of daily living (ADLs) and the quality of life (QOL) of older adults. In particular, identification of the factors that are more strongly associated with the presence or absence of cane use will make it possible for those involved in rehabilitation to focus on such factors, which may be useful for the future rehabilitation of older adults.
MATERIALS AND METHODS
Participants
This is a cross-sectional study. The participants were community-dwelling middle-aged and older adults who took part in the physical fitness tests held at local community centers and day rehabilitation centers for the purpose of preventing caregiving and promoting health. Some participants were certified for long-term care and used day care rehabilitation. Recruitment was carried out by displaying posters, posting on the website, and calling on staff. The exclusion criteria were participants aged ≤64 years, who used a walker or wheelchair, and who have missing values. The participants in the physical fitness test were fully informed of the study content and purpose, and their consent, and cooperation were obtained thereafter. This study was conducted after obtaining approval (No. 23TXV20) from the Ethics Review Committee of Nishikyushu University.
Measurement Items
Basic data
As basic data, sex, age, and disease were recorded, and height, and weight were measured. Diseases were classified into cerebrovascular disease, orthopedic disease, and internal medicine-related diseases (hypertension, diabetes, rheumatoid arthritis, chronic kidney disease) based on the recorded data. As some of the participants were certified as requiring care, the level of care was recorded. The certification of long-term care needs is defined by the long-term care insurance system introduced in 2000 to address the increasing population aging and the consequent need for long-term care.14) The certification of care needs consists of two main levels, “support” and “care,” and is classified into seven levels: 1–2 for support and 1–5 for care.15)
Whether or not a cane is used
Verbal questions were asked regarding the presence or absence of cane use. The respondents were asked self-reported whether they used a cane indoors or outdoors, what type of cane (T-cane or Q-cane) they were using, and the number of canes used when walking (unilateral or bilateral).
Physical function
Toe pressure strength in the standing position was measured using a toe pressure measuring instrument (S-14030; Takei Scientific Instruments Co. Ltd., Niigata, Japan). The measurement limb position was standing, and the ankle joint was fixed with a belt. The respondents were instructed to place only their toes on the force plate and exert pressure on the floor with the toes. Upper limb support and ankle plantar flexion were not allowed during measurements. Measurement of toe pressure strength in the standing position has been reported to be a reliable and valid assessment method.16) Measurements were taken twice on each side, and the maximum value was used.
Handgrip strength was measured using a Smedley grip strength meter (T.K.K. 5401; Takei Scientific Instruments Co. Ltd.). The values obtained have been reported to be highly reliable.17) The measurement limb position was standing, and the grip width was adjusted so that the proximal interphalangeal joint of the index finger was at 90°. Measurements were taken twice on each side, and the maximum value was used.
Knee extension strength was measured using a hand-held dynamometer (μTasF-1; ANIMA Corporation, Tokyo, Japan). The values obtained have been reported to be highly reliable and clinically useful.18,19) The measurement limb position was sitting, with the sensor fixed to the distal part of the lower leg with a belt. Measurements were taken twice on each side, and the maximum value was used.
The 30-second chair stand test (CS-30) was conducted with a digital stopwatch. This method has been reported to be highly reliable for assessing lower limb muscle strength.20,21) The upper limbs were crossed in front of the chest, and the participants were asked to stand up and sit down as fast as possible for 30 seconds. The number of repetitions was recorded.
The open-eyed one-leg standing time was measured using a digital stopwatch. This method is used to assess balance ability and has been reported to be reliable and clinically useful.22,23) The participants were instructed to continue standing on one leg, and measurements were started when the foot was raised. The end criterion was set as when both feet were on the ground, when assistance was deemed necessary, when the raised leg touched the opposite leg, or when the supporting leg moved, with an upper limit of 120 seconds. Measurements were taken once on each side, and the maximum value was used.
Cognitive function
Mini-Mental State Examination (MMSE) was employed to assess cognitive function. This method has been reported to be reliable and is widely used to assess cognitive function.24) MMSE is an 11-item, 30-point questionnaire; the higher the score, the higher the cognitive function, and the lower the score, the higher the cognitive impairment.25)
Psychological assessment
Depressed mood was assessed using the Kihon Checklist (KCL). The KCL is a questionnaire developed by the Japanese Ministry of Health, Labour, and Welfare and used worldwide owing to its advantages.26) Questions are asked in seven domains: instrumental ADLs (Questions #1–5), physical function (Questions #6–10), nutritional status (Questions #11–12), oral function (Questions #13–15), social isolation (Questions #16–17), cognitive function (Questions #18–20), and depressed mood (Questions #21–25). Questions are answered with “yes” and “no,” and the higher the score, the more likely it is that care prevention services and care certification are needed.27) The study used the total score of the depressed mood (Questions #21–25) of the assessed KCL (Supplementary Table S1). The depressive mood items of the KCL serve as independent depressive mood assessments in several previous studies.28,29)
Fear of falling was assessed by asking the question, “Do you have a fear of falling while walking?” The participants were also asked about their history of falls in the past year.
Statistical Analysis
Statistical analysis was conducted to examine the characteristics of each measure by comparing each measure with and without the presence or absence of cane use in ADLs. The chi-squared test was conducted with phi (φ) coefficient, Fisher exact probability test with Cramer’s V, t-test with Cohen’s d, Mann–Whitney U test with r to calculate the effect size, and 95% confidence interval (CI) of the effect size to confirm the extent of difference. Binomial logistic regression analysis was also conducted to investigate the factors associated with the presence or absence of cane use in ADLs, with the presence, or absence of cane use as the dependent variable. In Model 1, physical, and cognitive function, fear of falling, and history of falls, which may be associated with cane use, were used as independent variables. In Model 2, sex (ref: male), age and disease (ref: none) were introduced as covariates to adjust for confounders. In this study, it was thought that the number of participants was insufficient for the analysis method. Therefore, a bootstrap resampling of 1,000 times was performed to assess the validity of the results obtained from the binomial logistic regression analysis. The bootstrap method was considered to be more realistic for estimating the population from actual data.30) The possibility of using regression equations was determined using a model chi-squared test. In addition, the goodness-of-fit of the logistic regression equation was checked using the Hosmer–Lemeshow test, and a variance inflation factor (VIF) was calculated to avoid multicollinearity. The statistical significance level was set at 5% (p<0.05). SPSS software (version 28.0; IBM, Armonk, NY, USA) was used for the analysis.
RESULTS
Characteristics of the Participants
The characteristics of the participants are presented in Table 1. A total of 243 community-dwelling middle-aged and older adults participated in the physical fitness test, of whom 160 (mean age, 79±7 years; 73% female) were included in the final analysis (Fig. 1), excluding 11 participants aged 64 years or younger, three who needed assistance with walking, seven who used a walker or wheelchair, and 62 who had missing values. There were 108 participants (mean age, 77±7 years; 69% female) in the cane-using group and 52 (mean age, 83±6 years; 79% female) in the cane-non-using group. Four participants used a Q-cane, and none used a cane bilaterally. Comparison of each measure between the two groups showed that older adults who used a cane were significantly older (p<0.001, ES=-1.01), were shorter (p<0.001, ES=0.60), had a higher body mass index (p=0.044, ES=-0.34), had more diseases (p<0.001, ES=0.44), and had long-term care certification (p<0.001, ES=0.73). The cane-using group exhibited significantly weaker toe pressure strength in the standing position (p<0.001, ES=1.21), handgrip strength (p<0.001, ES=0.79), and knee extension strength (p<0.001, ES=1.28) as well as worse CS-30 (p<0.001, ES=1.86) and open-eyed one-leg standing time (p<0.001, ES=1.23). Furthermore, the cane-using group was significantly more likely to have declined cognitive function (p<0.001, ES=0.45), depressed mood (p<0.001, ES=0.33), fear of falling (p<0.001, ES=0.33), and a history of falls (p=0.014, ES=0.22).
Factors Associated with the Presence or Absence of Cane Use
The results of a binomial logistic regression analysis to examine the factors associated with the presence or absence of cane use are presented in Table 2. Binomial logistic regression analysis was conducted using the presence of cane use in ADLs as the dependent variable and toe pressure strength in the standing position, handgrip strength, knee extension strength, open-eyed one-leg standing time, MMSE, depressed mood, fear of falling, and history of falls as independent variables, which may be associated with cane use. The results indicated that open-eyed one-leg standing time (odds ratio [OR]=0.83; 95% CI, 0.74–0.94; p=0.002) and depressed mood (OR=2.10; 95% CI, 1.15–3.84; p=0.016) were significantly associated with cane use. In Model 2, sex, age and disease, which were considered as covariates, were introduced to adjust for confounding. The results indicated that open-eyed one-leg standing time (OR=0.81; 95% CI, 0.70–0.93; p=0.003) and depressed mood (OR=2.78; 95% CI, 1.31–5.91; p=0.008) were associated with cane use, even after adjustment for confounders. In the binomial logistic regression analysis using the bootstrap sample to confirm the validity of the results, it was also found that, as in the original model, only the time spent standing on one leg with open-eyed one-leg standing time and depressed mood were associated with the cane use. The chi-squared test for Model 2 was significant at p<0.001, the Hosmer–Lemeshow test was p=0.918, and the discriminant hit rate was 89.9%. The results of the VIF confirmed multicollinearity between CS-30 and knee extension strength (VIF >5). Since previous research has shown that knee extension strength is associated with gait performance with walking aids,31) CS-30 was excluded from the independent variables, whereas knee extension strength was included as an independent variable as a measure of lower limb muscle strength.
DISCUSSION
This study aimed to (1) examine the factors associated with the presence or absence of cane use in older adults from a comprehensive set of assessed variables and identify factors with stronger association as well as to (2) determine whether toe muscle strength, which we have systematically studied, is relevant to the presence or absence of cane use. The results indicated that open-eyed one-leg standing time and depressed mood were significantly associated with the presence or absence of cane use, whereas toe muscle strength was not.
When each measure was compared according to the presence or absence of cane use, those who used a cane were older adults and had low physical and cognitive function, depressed mood, fear of falling, and a history of falls. Older adults have been reported to be at an increased risk of falling due to low muscle strength, balance ability, and cognitive function.32-34) Furthermore, fear of falling, and history of falls have been demonstrated to be significant risk factors for re-falls.35) Thus, it is suggested that the participants in this study who used a cane may have used a cane and prevented falls because of their low physical and cognitive functions, history of falls, and fear of falling. Because physical and cognitive functions have been reported to decline with age,36) the significant difference in age in this study is valid. Also, a study including only older adults in need of long-term care who used day care rehabilitation demonstrated that older adults who used walking aids, including canes, had lower physical, and cognitive functions, thus supporting our results.37)
Binomial logistic regression analysis revealed that the presence or absence of cane use was significantly associated with open-eyed one-leg standing time and depressed mood in the final model. However, toe muscle strength was not associated with the presence or absence of cane use, hence contradicting the hypothesis. A cane provides stability by increasing the base of support, reducing the risk of falling.38) On the other hand, it has been pointed out that it may cause a decrease in walking speed.38) Toe muscles strength are mainly used for terminal stance of the stance phase during walking, and it has been suggested that they contribute to improving walking speed.12) In this way, while the use of a cane improves stability and causes a decrease in walking speed, toe muscle strength contributes to an increase in walking speed, so we can assume that the effects of the two cancel each other out and there is no significant association. This study highlights that open-eyed one-leg standing time and depressed mood are stronger predictors of cane use than muscle strength, cognitive function, or fall history. As aforementioned, balance ability has been shown to be associated with risk of falling, and among these, the authors reported that the one-leg standing time used as a variable in this study may be the most useful assessment for identifying risk of falling.33) Walking aids, including canes, assist older adults with poor balance and promote independence in ADLs.39) These findings indicate that older adults with impaired balance ability need to be prescribed a cane. When depressive tendency occurs, the individual’s movement becomes sluggish, disabling them to walk.40) There is a concern that reduced balance and walking abilities in individuals with depression may increase the risk of falling.41) A systematic review has also found that depressive tendencies are associated with balance and walking abilities.42) Interestingly, the neuromodulator mechanisms43) that control gait and posture (e.g., dopaminergic pathways, prefrontal cortex, and basal ganglia neural circuits) have been found to be involved in the pathophysiology of depression.44) Thus, neurophysiological aspects also suggest that depressive tendencies are associated with balance and walking abilities. These findings suggest that individuals with depressive tendencies have impaired balance and walking abilities, thus requiring prescription of a cane. On the other hand, while the present study is a cross-sectional study and therefore causality cannot be mentioned, it is possible that older adults who were prescribed a cane may have slipped into a depressive mood after the prescription. It can be inferred that older adults with reduced balance ability need a cane and are more likely to depressive states. In any case, it became clear that before and after prescribing a cane, it is necessary to pay attention to not only motor function, but also psychological aspects to evaluate using KCL. The results of this study have the potential to provide useful intelligence for older adults with depressive tendencies. Walking has been reported to have a beneficial effect on depression,45) and although further research is needed, prescribing a cane to an older adult with depression and who is anxious about walking may enable them to walk safely and may help increase the time and frequency of walking, giving them a sense of security about walking.
The strength this study is that we did not examine single factors, such as physical, or cognitive function alone, but rather included a comprehensive set of variables reported to be associated with the presence or absence of cane use. Thus, it was possible to identify factors more strongly associated with the presence or absence of cane use. Furthermore, this was the first study to hypothesize and test the hypothesis that there is an association between cane use and toe muscle strength.
This study has several limitations that need to be acknowledged. First, the sample size is small. The sample size in one group may be small for the logistic regression analysis in this study. Furthermore, the participants in this study were recruited from some regions in Japan. Therefore, we believe that generalization of the results requires not only increasing the sample size but also recruiting populations from various regions. Second, there is a concern regarding the depression assessment employed. When interpreting the results, it should be considered that the current evaluation is part of the evaluations included in the KCL developed in Japan. Third, there is a lack of information on the length of time the cane has been in use and how it began to be used. In the future, it will be necessary to obtain more information about cane use and interpret the results. Fourthly, the number of missing data (62 participants) was high. The reason for this is that, due to time constraints, not all measurements were completed. In the future, it will also be necessary to reduce the number of missing values by increasing the number of measurement staff to finish the measurements in a shorter time. Lastly, the present study is a cross-sectional study; thus, it is not possible to refer to causal relationships. However, we believe that this study provides valuable results in identifying factors that are more strongly associated with the presence or absence of cane use among older adults and can provide important information that can be useful when prescribing a cane.
In conclusion, this study demonstrated that balance ability and depressed mood were strongly associated with cane use in older adults. The findings suggest that older adults with impaired balance and depressive symptoms should be prescribed a cane. The results highlight the importance of assessing balance ability and depressive mood when prescribing canes to older adults.
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