By the end of August 2015, the Geriatric Society of China announced that Guangxi was the largest province in China with a population exhibiting good longevity rates [1
]. Wang et al. [2
] also studied regional longevity in China and reported Hechi City as one of the areas with high longevity levels in China. Hechi is a relatively underdeveloped area in Guangxi and the Zhuang people comprise its main ethnicity. The Bama Yao Autonomous County of Hechi is recognized as the “hometown of longevity in the world” and has aroused widespread global interest [3
]. However, other counties and cities in the Hechi area, which has six “longevity towns,” do not enjoy the same level of popularity (Bama Yao Autonomous County, Donglan County, Fengshan County, Yizhou City, Dahua Yao Autonomous County and Tiane County). The county we studied belongs to Hechi and is adjacent to Bama and is one of the six “longevity towns,”. The area is located in the northwest of Guangxi, the southern margin of the Yunnan-Guizhou plateau, in the middle reaches of Hongshui River. To date, no research has been conducted on the health status of the elderly in the county.
According to estimates, by 2050, the population of people aged 80 around the world would reach 400 million, 70% of whom can be found in the underdeveloped regions [5
]. Based on the data released by the National Bureau of Statistics of China, in 2016, the number of elderly population aged 60 and above has increased to nearly 231 million, accounting for 16.7% of the total population; meanwhile, the elderly population aged 65 and above has reached 150 million, accounting for the total population 10.8% [6
]. Recent estimates indicate that the proportion of Chinese adults aged 80 and above will increase from 11.5% in 2015 to 23.2% in 2050 [7
]. With the increasing number of elderly population in China, the proportion of those in rural areas accounts for about 70% of this population [8
]. Compared with China’s cities, rural areas, which are relatively backward in culture and economy, are being threatened by environmental degradation, declining schedule activities and chronic diseases. The burden on old-age security for the elderly in rural areas will be more important than ever before [9
]. Thus, the problem of ageing in rural areas is worthy of public attention than that in urban areas.
With the development of the ageing population, the health condition of the elderly and the major influencing factors have attracted significant scholarly attention. Dealing with the risks and burdens of disability caused by ageing is crucial. The ability of daily life (ADL) refers to the most basic and common body movements that people must perform repeatedly every day to live independently [11
]. ADL consists of physical activities of daily living (PADL) and instrumental activities of daily living (IADL) [12
]. Several studies [13
] found significant differences in ADL disability rates among the elderly in different regions. For example, a survey conducted by the Mexican Health and Ageing Research Center (MHAS) for older Mexicans aged 80 years and older found that in the 2000–2001 and 2010–2012 cohort studies, the MHAS ADL disability rates increased from 37.5% to 44.0%, indicating that, as time goes by, the disability rate of ADL increased as well [13
]. A survey of 23,815 elderly people in Brazil with an average age of 69.8 years reported an ADL disability rate of 30.1% [14
]. A 2002 study on the ADL disability rates of the elderly in China revealed the disability rates of 6.9%, 23.6%, and 42.7% among the age groups of 65–79, 80–89, and 90–99 years old, respectively (total disability rate: 41.0%) [15
]. At present, although many studies on ADL disability have been published, most have examined overall ADL or IADL disability. Few studies have analyzed disability from the overall effect on each item. Hence, the purpose of the current study is to investigate the possible influencing factors of disability (ADL, PADL, IADL, and 14 items) among the elderly people aged 60 and above, who are living in the county we studied (Guangxi Province, China).
As the aging population continues to increase, maintaining the functional capacity of older adults has become an urgent concern [20
]. The occurrence of ADL and IADL disabilities among the elderly is a complex process resulting from a combination of factors in medicine, sociology, psychology, and behavioral science [21
]. The results of the current study showed that the disability rates of ADL, PADL, and IADL among the elderly were 43.4%, 11.6%, and 42.4%, respectively. The ADL disability rate in the current study is higher than that of Lima-Costa’s findings for Brazilian elderly (30.1%) [14
] and Yin De-ting’s findings (41.0%) for Chinese elderly [15
], but lower than Downer’s findings (44.0%) for Mexican and Mexican American adults aged 80 and over [13
The IADL disability rate in the present study is higher than Shimada’s findings (26.7%) for 10,885 community-dwelling older adults aged 65 and enrolled in the NCGG-SGS [22
]. The trends of ADL and IADL disability rates were consistent at a higher level, whereas PADL has a relatively low disability rate; both findings are consistent with the results of other researchers [17
]. These findings might be related to the characteristics of PADL and IADL. PADL reflects the self-care ability of the elderly, whereas IADL reflects the elderly’s ability to live independently. The disability rate of IADL is higher than that of PADL, indicating that most elder people can take care of themselves, but they cannot live independently. This situation is similar to the research results of Jing Rui et al. [24
]. This similarity can be attributed to the fact that the elderly who participated in the present survey came from remote rural areas and, as such, their educational level was generally low. Except for the above findings, this study found that gender, age, education level, and whether someone had MetS were the influencing factors of ADL disability. Age, number of chronic diseases, and whether someone had MetS were the influencing factors of PADL disability. Gender, age, and education level were the influencing factors of IADL disability. The results of the study about the influencing factors of disability are similar to those of other studies [25
]. Previous research suggested that age, chronic disease, being female, having low economic income, and having low education level were considered as risk factors for disability. The above findings reveal that the disability of the elderly in the County is similar to the situation in other places, thereby suggesting that the local health administration can learn from the mature experiences of other places in designing future interventions.
Logistic regression analysis results showed that gender may be the influencing factor of ADL and IADL disability in the elderly, as females were more likely to encounter ADL and IADL disabilities than males. This finding is consistent with the results of past studies [6
]. A study of 9694 older people by Lina Mad [6
] found that females’ disability rate was 1.3 times than that of males. In the study of elderly people aged 65 and above, Chalise et al. found that the rate of disability in females IADL was 50.0%, which was significantly higher than that of males’ at 26.0% [29
]. The possible reason was that elder females who participated in the study were mostly illiterate, and in rural areas, they were rarely associated with the outside world. However, gender differences in three items (preparing a meal, performing household tasks, and taking medication) in the IADL were reversed. This finding is consistent with that of a Nara study in Japan, which found that the rate of instrumental daily life impairment in males was higher than that of females [31
]. The reasons might be related to local labor habits: local males are often responsible for physical activities outside the home and females are generally responsible for housework and child care at home. Thus, males are more likely to have disabilities than females. The probability that males or females are more likely to be disabled is different from the total ADL and IADL rates and in the above three items. Hence, this requires further investigation and subsequent follow-ups.
The trend chi-square test showed that the rate of disability increased with age. Logistic regression analysis results also indicated that age was the influencing factor for disability, as all the results (ADL, PADL, IADL, and 14 items) showed that the older the age was, the higher the OR value was. This finding is consistent with many studies [6
]. In a study of the global burden of disease, Salomon et al. [35
] found positive correlation between years of disability and life expectancy. Suzuki’s study of disability in Japan discovered that, although the functional capabilities of older people living in the Japanese community have improved over the past two decades, as age increased, the daily functional ability of the elderly worsened [20
]. Three possible factors can explain this. First, in terms of research site, the elderly involved in the survey are mainly doing farming activities in the rural areas. Second, with the increase in age, various organic or functional changes occur in the elderly, and the prevalence of chronic diseases has thus has increased. Third, given the high proportion of empty-nest elderly people in rural areas, psychological problems, such as loneliness and depression, are more common among this population. In addition, walking is recognized as a predictor for the onset of ADL disability in the elderly [36
]. Among the six items of PADL in this study, walking has the highest rate of disability, which also increases with age. Further, this finding supports the notion that the rate of disability increases with age. The reasons for the highest disability rate of using the telephone may be that, first, local economic conditions are poor, and some elderly people have never left the area. Mobile phones are new tools for them, and because they rarely interact with the outside world, they might have certain difficulties in using mobile phones. Second, many elderly people have declining hearing and vision as they age, which adds difficulty in making calls in daily life. Regarding the use of public vehicles, the local public vehicle is special, and tricycles are different from buses in cities. Many elderly people seldom go outside and if they do need to go out, they must have better ability in their physical coordination to get on and off vehicles. Many of them have difficulties in completing daily activities because the body function and coordination are declining. Hence, proposing measures allowing the elderly to maintain good daily living functions is an important and urgent task.
Meanwhile, educational level also served as an influencing factor of ADL and IADL. Five of the eight items of IADL showed that the lower the education level was, the higher the incidence of disability. Scholars believe that the high frequency of ADL disability is related to low education level [37
]. The results in this study may have been influenced by the fact that most of the elderly in this study are illiterate, and such situation could have affected the activities of IADL, such as using the telephone, doing financial management, and using public vehicles. In addition, elder people with lower education levels might have less attention to physical health, not to mention the prevention of chronic disease.
In this study, although the results of multiple factors failed to conclude that alcohol consumption was not a possible influencing factor for the occurrence of ADL, PADL and IADL, it was concluded that alcohol consumption could be influencing factor for seven items. From the OR value, someone with alcohol use were less likely to occur disability than someone without alcohol use. Human activity and cognitive function were affected by alcohol use [41
]. Studies have shown that alcohol can cause cognitive impairment because large drinkers have lower prefrontal cortex volume, activity, and oxygenation [42
]. But other studies have found that moderate drinking not only slows cognitive decline in women [43
], but also improves cognitive performance in older people [44
]. Other studies have found moderate drinking did not affect or decrease the incidence of dementia and cognitive impairment [45
]. The results of this study suggested that alcohol use might play a role in alleviating functional decline in certain daily activities. It was similar to the results of Stampfer et al. [43
], it needs further research to prove it.
Studies have shown that the number of chronic diseases is associated with impaired ADL, and the more chronic diseases there are, the higher the rate of ADL disability would be [46
]. Elderly people with high blood pressure [49
], diabetes, or cerebrovascular disease [50
] are susceptible to ADL or IADL. In this study, 65.7% of the elderly had one or more chronic diseases. This is consistent with the results of a recent census in the United States, which concluded that about 66.5% of older adults with one or more disabilities have difficulty in moving [51
]. Logistic regression analysis showed that the probability of PADL disability in the elderly with one or two chronic diseases was 2.625 and 4.431 times higher than that of elderly without chronic diseases, respectively. The results of this study did not show a relationship between chronic disease and ADL or IADL disability. However, the results for five items showed that, with the increase in the number of chronic diseases, the possibility of disability in the elderly gradually increased. These items included walking and bathing in PADL and preparing a meal, taking medication, and grocery shopping in IADL. Except for taking medication, the other four items had similar characteristics, as the elderly needed to move their bodies within a large area. This finding is consistent with the results of Remillard et al. [52
], who found that adults with long-term movement disorders must face multiple challenges related to ADLs/IADLs as they age.
Studies have also found that MetS is significantly related to the ADL and IADL of the elderly living in the community [53
]. However, other studies have shown that MetS is associated with mobility restrictions but not related to the disability of ADL or IADL in older Mexican Americans [56
]. The findings of the present study indicated that the elderly with MetS were more likely to have ADL and PADL disability than those without MetS. Although the overall IADL did not enter the regression equation, part of the IADL items entered the equation. Of all the PADL items, three items entered the regression equation: walking, grooming, and toileting. Meanwhile, of all the items in the IADL, five items entered the equation: doing financial management, preparing a meal, performing household tasks, doing some washing, and grocery shopping. The above results suggest that we should focus on the occurrence of MetS in this population. In the intervention measures, elderly people without MetS should do regular physical examinations, so that their metabolic values fall within the normal range, thus reducing the probability of physical disability.
This study has the following highlights. To the best of our knowledge, this is the first study to analyze the influencing factors of disability among the elderly in the county (Guangxi Province, China). Second, many current studies have analyzed the disability of the elderly but only by analyzing the overall ADL, PADL, IADL and few have studied each item in greater detail. In comparison, this study analyzed the risk factors for disability from ADL, PADL, IADL and each activity (14 items) to explore the possible factors of disability among the elderly living in the mountain areas. The study provides a scientific basis by offering basic data for further interventions, which can allow the local elderly to have a better quality of life. Third, for certain influencing factors, although multivariate analysis failed to show certain factors were risk factors for ADL, PADL, or IADL disability, a risk factor was indicated in certain specific activities (14 items reflected).
Several aspects, however, need further attention. First, as this survey is a cross-sectional study, it cannot determine the causal relationship between influencing factors and disability. Second, as the data were self-reported, individual bias may have influenced the information. Third, the number of samples in this study was not large enough. For this reason, enlarging the number of samples is needed to increase the credibility and extensibility of the results. This study is the baseline survey of our project, and we aim to do a follow-up study on the elderly who have participated in the survey every three years in the future.