Does social support affect development of cognitive dysfunction in individuals with diabetes mellitus?

OBJECTIVES: To determine cognitive functions and perceived social support (SS) among individuals with diabetes mellitus (DM), and the effects of SS on the development of cognitive dysfunction (CD).
METHODS: This cross-sectional study was conducted in 121 patients with DM presenting at the Endocrinology Clinic of Cumhuriyet University Health Services Application and Research Hospital, Sivas, Turkey between April and June 2014. Data were collected utilizing the "Patient Assessment Form", "Standardized Mini Mental State Examination (SMMSE)" and "Multidimensional Scale of Perceived Social Support (MSPSS)".
RESULTS: The mean score obtained for DM patients from the SMMSE was 21.55±5.7, with 65.3% found to have cognitive impairment. The total mean score of the participants for MSPSS was considered moderate (66.61±14.42). There was a significant positive correlation between cognitive function and SS (r=0.273, p=0.002). It was determined that individuals with CD had low levels of perceived SS, and that insufficient support from families and significant others contributed to the development of CD (p=0.008).
CONCLUSION: In this study, it was determined that  the cognitive function of individuals with DM was impaired and would improve as the perception of SS increased, and that perceived SS would affect the development of CD. Therefore, health professionals can contribute to the improvement of cognitive function of individuals with DM by facilitating the use of SS sources.

The prevalence of diabetes mellitus (DM), a major public health problem affecting people’s quality of life - physically, mentally, socially, and economically,1 is on the rise in Turkey and the whole world. While 8.4% of the adult population suffers from DM worldwide, this rate is approximately 15% in Turkey.2 Diabetes mellitus leads to damage in a variety of tissues and organs over time. In the literature, DM is reported to impair cognitive functions due to damages it causes to the central nervous system.3 Cognitive function can be impaired in individuals with DM due to abnormalities in insulin secretion and glucose metabolism.4,5 Good cognitive function in diabetic individuals is important, since it facilitates metabolic control and treatment management.6 Therefore, early detection of cognitive impairment, and the implementation of effective treatment and coping methods will help people with DM to fulfill their professional and social activities, and thus, will facilitate management of the disease.7 One of the factors that affect diabetic individuals’ compliance with the treatment of DM and health outcomes is the perceived social support (SS). To manage the disease, an individual with DM needs the support of family and other individuals in the social environment, which he/she is in.8 The literature states that adequate SS will help a person to change his/her negative health behaviors, to increase his/her effectiveness, and to gain more control over his/her emotional state.9 The presence of SS in diabetic individuals affects their healthy eating habits’ compliance with treatment,8,10 and self-care processes specific to DM.11,12 In addition, the presence of perceived SS may be particularly useful in coping with difficulties likely to occur due to treatment.13 Cognitive dysfunction (CD) is a complication considered in the background in individuals with DM.7 Social support facilitates adaptation to treatment, and thus, reduces the likelihood of the development of complications.8,10 In the literature, there are studies investigating the effect of diabetic individuals’ perception of SS on metabolic parameters10,14 and other complications of DM.15 This study was conducted to determine the cognitive function and perceived SS among individuals with DM, and the effect of SS on the development of CD. This study may help determine whether SS provided for individuals with DM has an effect on cognitive functions such as attention, registration, and recall. A higher perceived SS is thought to positively contribute to the regulation of blood glucose levels, and thus, to prevent the deterioration of cognitive function caused by DM.

Methods

This cross-sectional study comprised 172 patients treated for DM in the Endocrinology Clinic of Cumhuriyet University Health Services Application and Research Hospital, Sivas, Turkey between April and June 2014. A total of 121 patients diagnosed with DM for at least 6 months, literate, able to communicate, did not have a diagnosis of any psychiatric illness, and willing to complete the questionnaires were included in the study sample. The remaining 51 diabetic patients had major depression disorder, were taking psychoactive or depression medication (anticholinergics, narcotics, antidepressants, benzodiazepines or tranquilizers), unable to communicate verbally, and/or refused to participate in the study and were excluded.

Data collection tools

Data were collected utilizing the Patient Assessment Form, Standardized Mini Mental State Examination (SMMSE), and Multidimensional Scale of Perceived Social Support (MSPSS).

Patient assessment form

Socio-demographic and disease-related characteristics were evaluated with this form. The form prepared by the researchers included items on age, gender, marital status, educational status, occupation, type of DM, duration of the disease, and presence of other chronic diseases. The results of biochemical analysis of the patient, fasting (preprandial) blood glucose (FBG), and hemoglobin A1c (HbA1c) values were recorded. Two diabetes specialists, and 3 academicians were interviewed regarding the convenience of the questionnaire.

The SMMSE

The participants’ cognitive functions were evaluated using the SMMSE. The Turkish validity and reliability study of the test was conducted by Güngen et al.16 The maximum possible score to be obtained from the 11-item test, which has 5 domains (orientation, registration/memory, attention, recall, and language) was 30 points. According to the inter-rater reliability study of the test, r was 0.99, and the kappa value was 0.92.16 In order to evaluate CD in individuals with DM, the scores obtained from the test were divided into 2 categories as in Tekin et al’s17 study; while the scores between 25 and 30 points indicated the absence of CD, the scores between 0 and 24 indicated the presence of CD. In this study, the Cronbach’s alpha value of the test was 0.84.

The MSPSS

The MSPSS scale was adapted in Turkish by Eker et al18 in 1995 consisting of 12 short items, which subjectively evaluate the adequacy of SS from 3 different sources. The 7-point Likert-type scale includes 3 subscales: each of which consists of 4 items: family, friends, and significant others. Each sub-scale’s score is calculated by summing up the scores of 4 items in the sub-scale. The minimum of 12, and maximum of 84 possible scores could be obtained from the entire scale. The scale does not have a cut-off score. Higher scores indicate that the perceived support is high, whereas lower scores indicate either the support is not perceived, or the person does not receive any support. While the Cronbach’s alpha reliability coefficient of the original scale was 0.85, it was 0.77 in our study.

Data collection

Data were collected using face-to-face interviews with DM patients, and carried out by the same person. Interviews were conducted in a separate interview room, such that the participants could answer questions comfortably.

Statistical analysis

Data were analyzed using the Statistical Package for Social Sciences version 14 (SPSS Inc., Chicago, IL, USA). Socio-demographic characteristics of the individuals with DM, and features of the disease were evaluated as means and percentages. To calculate the mean scores for the scales used to determine the participants’ cognitive functions and perceptions of SS, means and standard deviation were used. To compare the cognitive function levels of individuals with the independent variables, student t test, Mann-Whitney U-test, one-way ANOVA, or Kruskal-Wallis test was used, considering whether the data distribution was normal or not. The relationship between SS and cognitive function was assessed using Pearson’s correlation and linear regression analysis. Uni-directional ANOVA was used to compare the mean scores of SS according to whether there are CD in individuals, or not.

The study was approved by the Non-interventional Clinical Research Ethics Committee of the university. In addition, written permission was obtained from the institution where the study was conducted. Verbal and written informed consent was obtained from all study participants.

Results

The mean age of the participants was 57.2 ± 13.32 years. Most were female, married, primary school graduates, and housewives. A total of 14.9% of the participants were smokers, 7.4% used alcohol, 42.1% were obese, 34.7% had DM for more than 11 years, and 90.1% had type 2 DM. The participants’ mean FBG level was 175.65 ± 80.91 mg/dL, mean HbA1c level was 10.78 ± 2.74, and 62% had one or more chronic diseases. Among these chronic diseases, the most common was hypertension (52.1%). According to the study sample, 36.4% of the participants took both oral antidiabetics and insulin, 78.5% took their medicine regularly, 43% paid attention to their diet, 20.7% exercised regularly, and 71.1% had no family history of Alzheimer’s disease, or dementia. The mean subscale scores the participants obtained from the SMMSE and MSPSS are shown in . When the SMMSE total score was evaluated in the research (21.55 ± 5.72), CD was detected. According to the evaluation of the subscale scores of the SMMSE, 65.3% of the participants were found to have CD. Evaluation of the cognitive functions of the participants revealed that the most affected subscale of the SMMSE was attention (1.79 ± 1.94), while the least affected was orientation (8.87 ± 1.82). When the participants’ perceived SS systems were evaluated, the highest and lowest scores were obtained from the family (24.04 ± 5.04) and friend subscales (19.17 ± 6.62). The comparison of the demographic and disease characteristics of the participants in terms of the mean scores for the SMMSE is shown in . From the study sample, those who were 56-75 years of age, female, literate but not graduated from any school, and/or housewives, had another chronic illness, or did not exercise regularly had low mean SMMSE scores. The relationship between the SMMSE and MSPSS is provided in . There is a significant positive relationship between the mean total scores obtained from the 2 scales (r=0.27; p<0.01, ). A significant positive correlation (r ranging from 0.184-0.273) was determined between family support and orientation and language subscales (p<0.05), and between support from significant others and orientation, attention, recall and language subscales (p<0.01). This finding suggests that individuals with DM may have better cognitive function as their perceived SS increases. The results of the t test on the significance of regression coefficients, indicate that the MSPSS general dimensions variable is a significant precursor on SMMSE general score (R=0.273, R2=0.075, p=0.002). The comparison of the mean scores for SS according to whether the participants had CD or not is shown in . In accordance with the correlation analysis, the participants with CD were determined to have significantly lower SS mean scores than those without CD (p=0.008). It was also determined that support especially from family and significant others affected the development of CD in individuals with DM.

Table 1

Distribution of mean subscale scores among the diabetic participants.

Table 2

Comparison of the demographic and disease characteristics of diabetic participants in terms of the mean scores for SMMSE.

Table 3

Relationship between the Standardized Mini Mental State Examination (SMMSE) and Multidimensional Scale of Perceived Social Support (MSPSS).

Table 4

Relationship between perceived social support and cognitive dysfunction in individuals with diabetes mellitus.

Discussion

Cognitive dysfunction is a serious complication that people with DM are most likely to have, however, it is not as well known as other chronic complications.5,19 The study found that more than half of individuals with DM have symptoms of cognitive function disorder. Studies conducted recently have revealed that the prevalence of CD is on the increase in individuals with DM.20-22 In studies that compared individuals with DM with those without DM, it was found that SMMSE test scores were lower,23-25 and CD was 1.5 times more prevalent with DM group.7,26 It is reported that people with DM develop CD due to complications of DM, such as hyperglycemia, or due to other diseases accompanying DM or caused by DM,20,27 or age, or diabetes type.28 In this study, it was supposed that CD in individuals with DM developed as a result a failure in the regulation of glucose resulting from the following factors: increased age; presence of another chronic disease; and not complying with proposed treatment options other than pharmacological treatments, such as regular exercise. For instance, in their 2-year follow-up study, Yamamoto et al29 determined that lifestyle changes, such as joining an exercise program, or having medical nutrition therapy prevented the deterioration of cognitive functions. In their study, Mahakaeo et al30 found an association between good glycemic control and less cognitive impairment. The results of these 2 studies indicate that effective disease management is of importance in controlling cognitive function.

In patients with DM, cognitive domains, such as memory, psychomotor speed, executive function, processing speed, and verbal fluency are especially adversely affected.5,6 In this study, it was determined that of the cognitive domains, the most adversely affected one was attention. In a meta-analysis involving individuals in the adult group, from the cognitive domains, attention, perception, psychomotor speed, cognitive flexibility, and visual perception were affected significantly more in individuals with DM compared with healthy individuals.31 In another study performed in patients with DM,32,33 it was emphasized that learning, memory, mental clarity, and perception domains were affected. If domains, such as perception of attention, recall, language, and registration are adversely affected in people with DM, this may prevent those people from complying with the treatment, or may accelerate the development, or severity of complications related to DM. Therefore, it seems to be important that health professionals should regularly evaluate cognitive functions in individuals with DM, and that they should encourage patients to comply with treatment in order to prevent complications from developing.

One of the factors affecting compliance with the treatment and health outcomes in individuals with DM is the perceived SS.8 In the study, it was determined that the level of perceived SS among the participants was good, and most of the SS was provided by families. Data obtained from the study revealed that although the level of family support was high in the participants, their FBG and HbA1c levels were not at the desired level. In studies however, it has been reported that family support, including guidance provided by the family to manage DM has a positive effect on patients’ improving behavior to comply with the treatment,34,35 and achieving good glycemic control.15,36 This findings of the study suggest that patients had trouble using available SS effectively. Therefore, health professionals should raise both patient’s and families’ awareness of disease management, and include them in the treatment process by encouraging them to cooperate with the health care team.

The relationship between SS and disease management and prevention of DM-related complications is an issue that has been investigated recently.8 In our study, it was found that the perception of SS affected all domains of cognitive function, and that cognitive functions are better as the perception of SS increased. The support from the family and significant others was determined to affect the development of CD. The contribution of SS systems to disease management and compliance with the disease in patients with DM is high. With a good level of perceived SS, desirable behavioral and lifestyle changes, including eating habits can be achieved in people with DM. Thus, risk factors leading to CD, a less known complication of DM compared with other complications of DM, can be controlled. Therefore, the presence of SS and effective use of this support can be considered an important issue for the preservation of cognitive function in diabetic individuals.

Study limitation

It is inevitable that the results are subjective since perceptions of SS and cognitive function of individuals with diabetes are evaluated with scale results. “It is suggested that in further studies, this study should be repeated with a larger sample group.”

In conclusion, this study investigating the effects of SS on the cognitive function of individuals with DM revealed that the participants were not complement with diabetes management, and more than half had CD. It was determined that the level of perceived SS was moderate, and that while families provided most of the SS, friends provided the least. It was also determined that cognitive function improved as the perception of SS increased, and that inadequate support from families and significant others contributed to the development of CD. On the other hand, although the level of perception of SS in this study was good, the SS available was not effectively used in the management of the disease. In line with these findings, health professionals are recommended to determine individualistic risk factors that can affect the cognitive function of individuals with DM, to routinely evaluate the cognitive function of diabetic patients, to carefully follow especially those who are female, elderly, with low levels of education, have another chronic diseases, or do not exercise regularly in terms of CD, to include patients’ families and significant others in the treatment team from the day the patients were diagnosed with DM, and to arrange individual training programs for families.