Functional capacity of diabetic older adults living in a municipality in Northeastern Brazil

— Diabetes Mellitus is a disease that contribute to the loss of functional capacity in older adults. This study aimed to measure diabetic older adults’ functional capacity for activities of daily living (ADL) and instrumental activities of daily living (IADL). We carried out a descriptive and analytical cross-sectional study with older adults aged 65+ years at a specialized health care center of Brazil. The medical records of the patients were selected using non-probability sampling. In this study was found, significantly statistical, higher prevalence in ADL among persons aged 75+ years, those with low levels of education and relation between self-rated current health status. For dependence in IADL, it was common among 75+ years old people, those with lower levels of education, with income of up to 2 minimum wages and worse self-rated health. There is a need to work on public policies that contribute to active and successful aging by promoting the autonomy and functional independence of older adults in the household and community.


I. INTRODUCTION
Healthy aging is defined as including three main components: low probability of disease and functional disability, high cognitive and physical functional capacity and active engagement with life (Rowe & Kahn, 1997). Thus, health aging is much more than just the absence of disease; it includes the preservation of functionality (World Health Organization, 2015) Increased life expectancy points to the need to ensure that people not only live longer lives, but live healthier, active and independent lives. Therefore, it is necessary to put sustainable health care solutions into practice to tackle the potential increase in chronic diseases, cognitive decline or dependence and its consequences (Gomez et al., 2013).
Population aging has been accompanied by an increase in the incidence of noncommunicable diseases, particularly diabetes mellitus (DM), whose prevalence in the older population has been increasing due to the greater life expectancy of the population and increased survival of patients (Oliveira et al., 2017;Shaw et al., 2010;Wild et al., 2004).
In Brazil, nationwide data show that the incidence of DM increases with age as the rates range from 17.1% among men and 14% among women in people aged 55-64 years to 22.7% among men and 21.7% among women in people aged 65+ (Brasil, 2010).
Diabetes Mellitus is one of the top five non-communicable diseases that most contribute to the loss of functional capacity in instrumental activities of daily living (IADL) (Griffith et al., 2017) Researchers have reported that people with type 2 diabetes mellitus are at an increased risk of inability to perform activities of daily living as some comorbidities associated with diabetes can impair individual functionality (Araki & Ito, 2009). In addition, hyperglycemia increases dehydration, impairs vision and cognition and increases the risk of infection (Ismail-Beigi et al., 2011), which further contributes to functional decline.
It should be noted that changes in plantar sensitivity caused by diabetes interfere with the balance of older patients, thereby increasing the risk of falls, and decreased visual Thus, assessing functional capacity in older people with diabetes mellitus, which is the objective of the present study, allows to identify the physical and social needs of this population group and contributes to the elaboration of public policies and the development of health promotion and disease prevention and control strategies focused on functional impairment, which is a common problem in the older population.

II. METHODS
This descriptive and analytical cross-sectional study was carried out with older adults (65+ years old) receiving specialized care from Brazil's Unified Health System in the city of Fortaleza, Northeastern Brazil.
The study was conducted at a Center for Integrated Diabetes and Hypertension Care (Centro Integrado de Diabetes e Hipertensão -CIDH). CIDH is a reference center for Diabetes and Hypertension specialized care in the state of Ceará and it provides secondary health care for complications related to these diseases.
The sample size was estimated considering the number of older people (N=242,430) in the city of Fortaleza according to the 2012 DATASUS Report (Saúde, 2012). The formula for a finite population was used and the minimum sample size estimated was 246 older adults. The medical records of the patients were selected using nonprobability sampling according to their original reference numbers. We selected one out of every eight records as there were 1978 older people aged 65 years and older who have had diabetes for at least one year enrolled in the CIDH.
Inclusion criteria were people aged 65 years or older who have had diabetes mellitus for at least one year and who agreed to participate. Older adults with type 1 diabetes were excluded from the study.
Interviewers and data collectors were previously trained to apply the following data collection instruments: a) Identification form, which collected sociodemographic data (age, gender, marital status, level of education, income and retirement) and general health data (systemic diseases, cognitive problems, foot ulcer, use of medications, smoking, and drinking).
b) The Katz Activities of Daily Living (ADL) scale, which assesses performance in six self-care activities, namely bathing, dressing, toileting, transferring, continence, and feeding. The dependent variable was older adults' functional ability to perform ADL. The older adults were then classified as independentwhen they needed assistance in only one activity or in none of themand dependentwhen they needed assistance in two or more activities.
c) The Lawton and Brody Instrumental Activities of Daily Living (IADL) scale, which assesses eight variables related to mobility skills (using a telephone, going to distant places using some mode of transportation, shopping, housekeeping, doing the laundry, cooking, taking medication and handling finances). These skills are related to older adults' effective participation in the community and difficulties in performing them leads to a redistribution of tasks among family members who live with the older person (Lebrão & Laurenti, 2005). There are three response options for each activity on the scale, with a maximum score of 27 points. The score should be interpreted individually and the decline over time reveals deterioration. The lower the score on the scale, the worse the functional ability to perform IADL. The scale has not been validated for the Brazilian population; therefore, in some cases, a person's inability to perform tasks that are not usual (such as cooking) should be taken into consideration as it might impair the analysis of independence (M. Lawton & Brody, 1969; M. P. Lawton, 1971). For data analysis, the results were grouped into three categories: 27 pointsindependence, 26-18 pointspartial dependence, and below 18 pointsdependence (Pinto et al., 2016).
The results were organized and consolidated using the Statistical Package for the Social Sciences, Co. Chicago IL USA (SPSS) for Windows (version 23.0). Quantitative variables were described as means and standard deviations

III. RESULTS
A total of 248 older adults were analyzed: 140 women (56.5%) and 108 men (43.5% Older adults who earned up to two minimum wages (MW) had a 2.16-fold higher prevalence of dependence in ADL compared with those who earned more than 2 MW. Table 2 shows statistically significant associations between dependence in ADL and self-rated health at the time of the study (p=0.002) and in the past year (p=0.038). The older adults who rated their health as poor exhibited a 2.47-fold prevalence of dependence in some ADL when compared with those who rated their health as fair.
With regard to clinical data, dependence in ADL was significantly higher among people with a history of stroke (PR=2.42; p=0.036), self-reported cognitive problems (PR=4.15; p=0.001) and underweight measured by the BMI (PR=2.42; p<0.039). Table 3 shows the sociodemographic and behavioral characteristics of the older adults according to the level of functional ability to perform IADL. In all, 18.9% (n=47) of the participants were dependent and 51.6% (n=128) were partially dependent. The participants classified as dependent in IADL were over 75 years of age, had low levels of education and earned up to 2 minimum wages.
A total of 34.9% of the participants aged 75+ and 10.5% of those aged 65-74 years were dependent in some IADL (p<0.001). Additionally, dependence in IADL was observed in 25.7% of the illiterate participants and 3.8% of the participants with high levels of education (p<0.001). Dependence in IADL was also found in 19.3% of the participants who earned less than 2 MW and in 10.9% of those who earned more than 2 MW (p=0.011) ( Table 3). Table 4 shows the distribution of clinical characteristics of the older adults according to the level of functionality in IADL.
With regard to self-rated health in the past year, 26.5% of the participants who rated their health as worse and 16.1% of those who rated their health as better were dependent in IADL (p=0.019).

IV. DISCUSSION
The mean age of 73 years (SD±6.4) in the present study is in line with the age group most affected by type 2 diabetes as it is a chronic disease that lasts for many years (Santos et al., 2015) The higher prevalence of diabetes in women (56.5%) agrees with the findings of Bauduceau et al. (2014) and Doucet et al. (2012). However, it cannot be said that diabetes affects more women than men, but rather there is a greater search for health services among women (Diabetes Federation International, 2019). It is known that women seek health services more often than men, which can explain such difference (Levorato et al., 2014).
In the present study, the prevalence of functional dependence was higher among older adults aged 75+ and those who were illiterate and earned up to 2 MW compared with older adults under 75 years of age and those who were highly educated and earned more than 2 MW. Researchers have shown that people with low levels of income and education and with poor access to health services are more likely to develop diabetes mellitus (Schmitz et al., 2009).
In our study, most of the older adults (n=181, 72.9%) were dependent in at least one ADL, whereas in the study by Doucet et al. (2012) 73% of the patients were independent in all ADL. This difference may be related to a higher prevalence of diabetes in Brazil and the greater prevention and control of the disease among the French, which is directly related to their functional capacity and autonomy.  (2008), older adults' self-rated health was also associated with higher prevalence of dependence, that is, the older adults who rated their health as "poor" were more dependent in activities of daily living (p<0.042) compared with their peers who rated their health as fair and/or very good. This finding demonstrates a relationship between a negative self-perception of health and an increase in dependencies, as pointed out in another study (Confortin et al., 2015). In the present study, the highest prevalence rates of dependence in IADL were found among diabetic older adults aged 75+ and those with complete secondary education, income below two minimum wages, previous history of stroke, current peripheral neuropathy, heart failure and self-reported cognitive problems. These findings are strongly correlated with data found in Brazilian and international studies ( 2019), education proved to be a means for individuals to become aware of the most diverse risk factors for diseases and unhealthy working conditions, which could lead to less exposure to situations that could predispose people to diseases in the future and which may lead to an imbalance in the various organic systems as they age. Furthermore, education has proved to be a positive factor for strengthening psychosocial and behavioral aspects (Pereira et al., 2017).
A recent cohort study conducted in Brazil found no statistically significant association between income and disability in IADL, but the association between income and disability in ADL was significant. The researchers argued that in IADL people will directly depend on the environment in which they are inserted, that is, their interaction outside the home will depend on what is offered in the environment, such as quality sidewalks, accessibility in public places, green areas and leisure areas, among others ( More than a quarter of the diabetic older adults interviewed (26.5%) were dependent in IADL and rated their health as worse compared with the that in the previous year while the participants who presented with preserved functional capacity considered their health was the same as that in the previous year (39.5%). With regard the older adults who self-rated their health as poor, they have done so due to the negative impact the disease has on the subjective assessment of health in terms of quality of life. When older adults lose their independence to interact with the environment, they tend to have a more negative view about their health status ( A French longitudinal study assessed functional impairment in diabetic older adults using geriatric scales and found that glycated hemoglobin levels were associated with major neurocognitive disorder and diabetes complications and that there were multifactorial pathophysiological mechanisms linking such conditions, such as metabolic dysregulation, inflammation and chronic vascular damage. However, the mechanisms by which such associations occur need further research as psychiatric disorders, such as depressive disorder, can either occur in the early stages of dementia or even mimic it ( The present study has some limitations. One of them is the use of the Lawton & Brody scale, which despite being widely used in the local environment can be influenced by culture and gender and needs to have certain questions adapted to each environment. Another limitation is related to the Katz scale, as it does not asses walking. Although our study was carried out in a large reference center for patients with diabetes, its results cannot be extrapolated to the entire older population. However, our findings may

VI. CONCLUSION
We conclude that it is important to work on public policies that reduce social inequalities, as this study demonstrated that socioeconomic differences such as income and education are related to the loss of functional capacity in older adults. Autonomy and functional independence in the household and community should be encouraged in order to achieve healthy and active aging.