7-Morowati

JRHS 2009; 9(1): 48-51

Copyright © Journal of Research in Health Sciences

Relationships between Locus of Control and Adherence to Diabetes Regimen

Morowatisharifabad M(PhD)a, Mazloomy Mahmoodabad S( PhD)a, Baghianimoghadam M( PhD)a , Rouhani Tonekaboni N(MSc)b

aDepartment of Health Education. School of Health, Yazd Shahid Sdooghi University of Medical Sciences and Health Services, Iran

bDepartment of Nursing. Islamic Azad University, Tonekabon, Mazandara, Iran

Corresponding Author: Dr. Morowatisharifabad, E-mail: morowaty@yahoo.com

Received: 7 September 2008; Accepted: 25 February 2009

Abstract

Background: Adequate self-care in diabetes causes quality of life promotion and decreases the num­ber of inpatient cases. The health locus of control theory is used to assess adherence to diabetes regi­men in some studies in developed countries. The purpose of this study was to determine the status of diabe­tes locus of control in a sample of diabetic patients in Iran and investigation of it's relationship to adher­ence to diabetes regimen. 

Methods: This analytical and cross-sectional study was carried out on 120 patients referred to Yazd Diabe­tes Research Center. The Iranian versions of Diabetes Locus of Control scale and Diabetes Self-care Activities scale were used for data collection.

Results: Men were more internal locus of control and women were more chance locus of control. The attri­butions of external locus of control increased by age, while the internal locus of control increased by education level and chance locus of control decreased by education level. A positive association be­tween internal locus of control and adherence to diabetes regimen was found and there was a negative asso­ciation between chance locus of control and adherence to diabetes regimen.

Conclusion: Findings suggest that interventions aimed at improving internal locus of control may im­prove adherence to diabetes regimen but different diabetic patients have different attribution styles and inter­ventional programs to enhance diabetes self-care will be more successful if patients locus of con­trol is addressed.

Keywords: Locus of Control, Diabetes, Regimen, Iran

Introduction

The diabetes regimen is extremely complex (1) and it is generally accepted that a patient with a more complex regimen is less likely to be adherent than a patient with a less de­manding regimen (2). It is crucial that in­dividu­als with diabetes follow a strict treat­ment regimen in order to maintain con­trol over their blood sugar. This regimen in­cludes main­taining a proper diet, engaging in regular phy­sical activity or exercise, blood glu­cose moni­toring, and taking any pre­scribed medications (3). The high incidence of complications in in-dividuals with diabetes indicates that ad­her­ence to the diabetes regi­men is an eminent prob­lem. Furthermore, it has been estimated that about 20% of individu­als with type 2 dia­betes do not moni­tor their blood glucose (4) and only about 30% of individuals adhere to their exer­cise program (5).

Adherence has been defined as the degree to which a patients voluntary behavior corre­sponds with the clinical recommendations of health care providers (6). Kavanagh sug­gested that in order to increase adherence to the dia­betes regimen, it is important to deter­mine what predicts an individuals ability to maintain the treatment objectives after the ini­tial diabetes edu­cation program (7). Deter­mining reliable pre­dictors of adherence may allow for a better understanding of how to im­prove adherence to this regimen (3).

Various psychosocial variables have been pre­viously examined to determine their influ­ence on adherence to the diabetes regi­men. Pre­dictors such as personality, family be­haviors, health beliefs, demographic charac­teristics (8) and beliefs about personal control and social support (9) have been inves­tigated. In addi­tion, the Transtheoreti­cal Model, the Theory of Reasoned Action, and the Health Belief Model, have been em­ployed in the past as theoretical frameworks for investigating health behavior change and adherence to the diabe­tes regimen (10-13). Al­though results from these studies vary, they do merit the investigation of additional psychosocial constructs as possible predic­tors of adherence to the diabetes regimen.

The locus of control theory was developed by Rotter (14). The concept “locus of con­trol” refers to the belief individuals have for control they have over their lives. Control ori­entation, which describes to what extent ones actions are instrumental to goal attain­ment, was first meas­ured in Rotters inter­nal-external (IE) scale. Individuals with high internal scores were re­ported to be more likely than externals to exert efforts to control their environment and to take responsi­bility for their actions. An external lo­cus of control orientation indicates that goal attainment is attributed to external fac­tors out­side the control of the individual. The exter­nal orientation has been divided into “power­ful others” and “chance” (15).

Rotters (16) Social Learning Theory em­ploys locus of control as a generalized expec­tancy. Generalized expectancies are ap­plicable in situations in which an individ­ual has not had enough experience in a par­ticular behavior or task to develop specific ex­pectancies (14, 17). Therefore, locus of con­trol is applicable in more general or novel situations.

Health locus of control is defined as a gen­eral­ized expectation about whether ones health is controlled by ones own behavior or forces external to oneself (18). Health lo­cus of con­trol is comprised of two compo­nents, inter­nal locus of control and external lo­cus of con­trol. An individual with an inter­nal locus of con­trol believes that outcomes are a direct result of his or her own behavior. An indi­vidual with an external locus of con­trol be­lieves that out­comes are a result of ei­ther chance or powerful other people, such as physicians (19).

The health locus of control theory is used to as­sess adherence to diabetes regimen in some studies. According to Rodin, (20) an indi­vid­ual with high perceived control may have better health because he or she is more likely to take health-enhancing actions. This would suggest that enhancement of an individ­ual per­ceived control over his or her health may lead to improved personal health. In particular, individuals with diabetes may ad­here more closely to their regimen if they ex­perience an increase in perceived or inter­nal locus of con­trol. Indeed, research that has examined the relationship between percep­tions of control and adherence to the dia­betes regimen has found supporting evi­dence for the relation­ship between these two variables.

In a study, Macrodimitris et al. (21) exam­ined the relationship between perceived con­trol and HbA1c levels in 115 individuals with type 2 diabetes. Results indicated that per­ceived control was negatively related to HbA1c levels. Therefore, high-perceived con­trol has a beneficial affect on individuals with type 2 diabetes, as demonstrated by lower HbA1c levels. It was concluded that ones percep­tion of control over his or her con­dition is a good indicator of whether or not that indi­vidual will actually exhibit con­trol over his or her condition. A study con­ducted by Surgenor et al. (22) investigated the relationship between sense of control and metabolic control in 96 females with diabe­tes. Results were similar to those from Mac­rodimitris (21). Those par­ticipants that had op­timal HbA1c levels had significantly higher levels of sense of control in all three domains than those with poor HbA1c levels.

Although the above studies have shown an as-­sociation between LOC and adherence to dia­betes regimen, some others have found no link between LOC and adherence behaviors in dia­betic patients (23- 25). Moreover, these studies were conducted in western countries and there is no support for these findings from develop­ing countries, so, it was found to be benefi­cial to examine the relationship be­tween locus of control and adherence to dia­betes regi­men in a developing country. Therefore, the pri­mary pur­pose of this study was to determine if percep­tions of control for overall diabetes man­age­ment were re­lated to adherence to the dia­betes regimen in a sample of diabetic pa­tients in Iran.

Methods

Sample

This was a cross-sectional study. The non-probability sample consisted of 120 diabetic patients at Yazd Diabetes Research Center (DRC) in central Iran. Inclusion criteria were 1) being a recognized diabetic patient for at least 3 months, 2) having a medical file at Yazd DRC, 3) being able to speak Farsi and 4) lacking any severe mental disorders and Alzheimer's disease. A power analysis showed that 100 was the sufficient sample size to achieve a power of 80. To ensure sam­pling ade­quacy, 120 diabetic patients were recruited. Partici­pation was voluntary, and the study took place from July to August 2006. 

Instrumentation

The survey instruments consisted of a demo­graphic data form, Diabetes Locus of Con­trol scale (26) and diabetes self-care activi­ties scale (27). The demographic data form was used to gather participants age, gender, job, educa­tion level, marital status, type of dia­betes and du­ration of diabetes.

The Diabetes Locus of Control scale (26) was developed for use on participants aged between 18 and 80 yr. The scale consists of 18 items: 6 items measuring internal locus of control, 6 items measuring powerful others lo­cus of control, and 6 items measuring chance locus of control. A 6-point Likert-type scale is used in which 0 indicates strongly disagree with the statement and 5 in­dicates strongly agree with the statement. The Diabetes Locus of Control scale was used with success on young people as part of the Diabetes Control and Complications Trial (28) and was considered appropriate for use with the participants of this study. The scale was translated into Farsi by the in­vestigator. A back-translation tech­nique (29) was used to achieve a Farsi trans­lation, which preserved the denotation and connota­tion of each of the instrument items. The back-translated copy was compared to the original English by investigator to recog­nize incongruities. The Farsi translation was then adjusted with corrective re-translation, as nec­essary. The Farsi version of the scale was submitted to a panel of experts to evalu­ate its content validity. The panel consisted of five health educators with doctoral educa­tion and extensive academic expertise in health- re­lated areas of study. All five approved the con­tent validity of the instrument. The in­stru­ment was then pilot-tested with a group of diabetic patients (N= 30) to collect data to ex­amine the internal consistency of the scales. Specifically, Cronbachs Coefficient Alpha was computed for each of the scales. The reliabil­ity coefficients were .76, .67 and .79 for the internal locus of control, powerful others locus of control and chance locus of control scales, respectively. For the actual study, these indi­ces were .80, .65 and .82, re­spectively.  

Adherence to regimen was measured, using the Diabetes Self-care Activities scale (27). This measure allows participants to report how well they are adhering to their specific regimen. This is a 12-item self-report recall measure of adherence over the past seven days to five aspects of the diabetes self-care regimen, namely 1) healthy diet 2) insulin in­jecting 3) blood glucose testing 4) exercise and foot care and 5) smoking behaviors. The participants circle how many of the past 7 days they have adhered to their prescribed regimen on each of the above behaviors. Mean scores are collected for each self-care be­havior and a total adherence score can be obtained by summing the mean subscale scores (30). In this study, the smoking behav­ior scale was omitted in computing ad­herence to regi­men score because only 3% of subjects re­ported a history of smoking be­havior. Stages for validity and reliability of the scale were the same as Diabetes Locus of Control scale and were carried out at the same time. The scale yielded a Cronbach's al­pha of 0.66 in the pilot study and 0.68 in the actual study.

Procedures

The permission to conduct the study was ob­tained from the Committee for the Protection of Human Subjects at the Shahid Sadooghi University of Medical Sciences and Health Services in Yazd. The investigator attended the Yazd DRC to oversee data collection.  Data were collected using a one-time face-to-face private interview and were analyzed using the Statistical Package for the Social Sci­ences (SPSS).

Results

The 120 study participants ranged in age from 17 to 73 (mean= 53.28, SD= 10). The majority (60.8%) were female. All were mar­ried. Their education levels were 33.3% il­literate, 17.5% had reading, writing ability, 27.5% had primary school education and 21.7% had higher than primary school educa­tion. Most of the subjects were home­makers (60.8%). The overwhelming majority of the participants (82.5%) had type 2 dia­betic and the rest had type 1 diabetic. The du­ration of diabetes ranged from three months to 30 yr, with 9.8 as the average age and 6.8 as the standard devia­tion.   

The mean score for Adherence to regimen was 48.4 (SD=10.0). With regard to the LOC dimensions, Internal LOC solicited the high­est score with an average of 26.6 (SD= 3.2), followed by Powerful others LOC and chance LOC with the means of 23.2 (SD= 2.6) and 9.4 (SD= 6.6) respectively.        

A series of t-test for independent samples showed that 1) men significantly outscored women on the basis of  internal locus of con­trol, 2) women significantly outscored men on the ba­sis of chance locus of control and 3) gen­der differences on the basis of powerful other locus of control were not statistically sig­nificant. None of the type of diabetes dif­fer­ences based on locus of control scales scores was statistically significant. A series of one-way analysis of variance showed that type of job differences on the basis of inter­nal and chance locus of control scales scores were statistically significant, and in both cases, Tukeys HSD post hoc procedure showed that the differences between house­wives and self-employed were statistically sig­nificant. Re­sults are summarized in Table 2.

Table 2: Correlations among variables

Constructs

1

2

3

4

5

6

1.Adherence to regimen

1






2. Internal LOC

0.278**

1





3. Powerful others LOC

0.156

0.218*

1




4. Chance LOC

-0.191*

-0.181*

0.1

1



Pearson Product Moment Correlation Coeffi­cient (Pearson r) was used to describe the mag­nitude and direction of the bivariate as­so­ciations between Adherence to regimen scores and locus of control subscales scores. Results are summarized in Table 3.

Spearman rank order correlation coefficient showed a statistically significant positive cor­relation between internal locus of control and level of education (r= 0.216, P< .05) and a statistically significant negative correla­tion between chance locus of control and level of education (r= -0.192, P< .05)

Correlations among variables in men and women were different. Although there were no statistically significant correlations be­tween adherence to regimen and locus of con­trol subscales among men, the internal and power­ful others locus of control scale scores were positively correlated with adher­ence to regi­men among women (r= 0.451 and r=  0.251, respectively). Additionally, when type 1 dia­betic patients were excluded, statistically signifi­cant correlations between adherence to regimen and internal and chance locus of control were observed (r= 0.295 and r= -0.228, respectively).

Regression analysis was performed to ex­plain variation on adherence to diabetes regi­men based on internal and chance locus of control. As powerful others locus of control was not significantly associated with adher­ence to diabetes regimen, it was not included in regression analysis. The two variables to­gether accounted for 9.8% of the variation. However, internal locus of control was the only statistically significant predictor of ad­her­ence to diabetes regimen. Results are sum­marized in Table 4.

Table 1: Means and Standard Deviations for Locus of control Subscales Scores by Gender, Type of Diabetes and Subjects Job

Variables

Values

Internal LOC

P value

Powerful others LOC

P value

Chance LOC

P value

Gender

Female

26.05±3.13

0.001

23.36± 2.67

N.S

11.08±7.49

0.004


Male

27.57±3.13


22.97± 2.66


6.78±4.01


Type of Diabetes

Type1

26.38±2.99

N.S

23.47± 2.35

N.S

10.33±7.19

N.S


Type2

26.70±3.26


23.16± 2.37


9.24±6.57


Job

Employed

27.27±4.02

0.008

23.18± 2.68

N.S

7.09±3.40

0.000


Self Employed

27.80±2.06


22.88± 2.72


5.60±3.04



Housewives

26.06±3.15


23.34± 2.67


11.45±7.49


5. Age

0.178

0.124

-0.181*

-.230*

1


6.Duration of Diabetes

0.177

0.098

-0.048

-0.072

0.359**

1

*P < .05, **P < .01

Table 3: Results of the Regression Analysis of Internal and Chance locus of control as Predictor of adherence to diabetes regimen

Predictor

F

Beta

R2

P value

Internal LOC

6.351

0.252

0.098

0.006

Chance LOC


-.145


0.107

Discussion

Adherence to the diabetes regimen is consid­ered the greatest barrier in controlling this dis­ease and preventing its serious chronic com­plications (31). Although diabetes edu­ca­tion gives individuals with diabetes the knowl­edge for how to best manage their diabe­tes and maintain proper glucose con­trol, knowledge has not been shown to be a good predictor of adherence to the diabetes regimen (32). There­fore, individuals with dia­betes may be ac­quiring the knowledge for how to properly control their diabetes; yet, they are not suc­cessfully incorporating the life­style changes needed to implement it over time. This is evi­dent in the poor adher­ence rates reported for individuals with diabe­tes (4, 5, 33). There­fore, this study evalu­ated the status of diabe­tes locus of con­trol among diabetic patients and its related fac­tors and quality of its as­sociation with ad­herence to diabetes regimen in a cross-sec­tional design.

In general, subjects displayed internal locus of control, followed by powerful others and chance locus of control. These finding indi­cate that the participants considered them­selves to be the greatest influence on their ad­herence to diabetes regimen. Little is known about diabetes and locus of control. The findings, however, are very similar to those of Gilli­brand and Stevenson (12) and Hutton (34).

The studys male participants demonstrated in­ternal locus of control, whereas the fe­males displayed evidence of chance locus of control. Aalto and Uutela(13) did not find any as­sociation between locus of control and sex but in a study by Buckelew et al. (35) the younger male patients reported a stronger in­ter­nal attributional style and older male pa­tients relied more heavily on both chance and powerful other factors. Since the major­ity of Iranian women are homemakers, it was ex­pected that homemakers reported more chance locus of control and less internal lo­cus of con­trol. Moreover, the attributions of exter­nal locus of control are increased as age in­creases. Additionally, internal locus of con­trol is in­creased as education level in­creases, while chance locus of control is de­creased as edu­cation level increases. On the other hand, a positive association between in­ternal locus of control and adherence to dia­betes regimen was found and there was a negative association between chance locus of control and adher­ence to diabetes regi­men. This is similar to the findings of previ­ous studies (20-22) in devel­oped countries.

These findings suggest that interventions aimed at improving internal locus of control may im-prove adherence to diabetes regimen but dif­ferent diabetic patients have different at­tri­butional style. Counselors and educators should attend to the locus of control in their inter­ventional courses and programs. The fol­low­ing activities will enhance internal lo­cus of control attribution and could be used in inter­ven­tional programs.

Providing situations, which may encourage dia­betic patients for adherence to regimen;

Enhancing patients knowledge regarding the diabetes regimen;

Providing positive feedbacks to patients for their small successes, as any feeling of suc­cess may make them feel that they are in con­trol of their illness.

Acknowledgements

The authors thanks all those who partici­pated in this study, in particular Yazd Diabe­tes Research Center and, School of Health at Yazd Shahid Sadooghi University of Medi­cal Sciences for financial support. The authors declare that there is no conflict of interests.

References

  1. Glasgow RE, McCaul KD, Schafer LC. Barriers to regimen adherence among per¬sons with insulin-dependent diabe¬tes. J Behav Med. 1986; 9(1): 65-77.
  2. Lutfey KE, Wishner WJ. Beyond "com¬pliance" is "adherence". Improv¬ing the pro-s¬pect of diabetes care. Diabe¬tes Care. 1999; 22(4): 635-639.
  3. McCaul KD, Glasgow RE, Schafer LC. Diabetes regimen behaviors. Predicting adherence. Med Care. 1987; 25(9): 868-881.
  4. Evans JM, Newton RW, Ruta DA, MacDonald TM, Stevenson RJ, Morris AD. Frequency of blood glucose moni¬toring in relation to glycaemic control: observational study with diabetes data-base. BMJ. 1999; 319: 83-86.
  5. Kamiya A, Ohsawa I, Fujii T, Nagai M, Yamanouchi K, Oshida Y. et al. A clinical survey on the compliance of exer¬cise therapy for diabetic outpa¬tients. Diabetes Res Clin Pract. 1995; 27(2):141-145.
  6. Rand CS, Weeks K. Measuring Adher¬ence with Medication Regimens in Clini¬cal Care and Research. In Shumaker SA, Schron EB, Ockene JK, McBee WL, Eds. The Handbook of Health Behavior Change Springer Pub¬lishing Company Inc. New York, 1998: pp. 114-132.
  7. Kavanagh DJ, Gooley S, Wilson PH. Prediction of adherence and control in diabetes. J Behav Med. 1993; 16(5): 509-522.
  8. Travis T. Patient perceptions of factors that affect adherence to dietary regi¬mens for diabetes mellitus. Diabetes Educ. 1997; 23(2): 152-156.
  9. Tillotson LM, Smith MS. Locus of con¬trol, social support, and adherence to the diabetes regimen. Diabetes Educ. 1996; 22(2): 133-139.
  10. Anderson RM, Fitzgerald JT, Oh MS. The relationship between diabetes-re¬lated attitudes and patients' self-re¬ported ad¬herence. Diabetes Educ. 1993; 19(4): 287-292.
  11. Sullivan ED, Joseph DH. Struggling with behavior changes: a special case for clients with diabetes. Diabetes Educ. 1998; 24(1): 72-77.
  12. Aalto AM, Uutela A. Glycemic con¬trol,self-care behaviors,and Psychoso¬cial factors among insulin treated diabet¬ics: a test of an extended health be¬lief model. Int J behav Med. 1997; 4(3):191.
  13. Gillibrand R, Stevenson J. The ex¬tended health belief model applied to the ex¬perience of diabetes in young peo¬ple. Br J Health Psychol. 2006; 11(1): 155-69.
  14. Rotter JB. Generalized expectancies for internal versus external control of re¬in¬forcement. Psychol Monogr. 1966; 80(1): 1-28.
  15. Norman P, Bennet P. Health locus of control. In: Conner M, Norman P, Eds. Predicting health behaviour. Open Uni¬versity Press, Buckingham, 1996: pp. 6294.
  16. Rotter JB. Social Learning and Clini¬cal Psychology. Prentice Hall, USA, 1954.
  17. Wallston KA. Assessment of control in health-care settings. In Steptoe A, Ap¬pels A, Eds. Stress, Personal Control and Health John Wiley & Sons Ltd, Brus¬sels-Luxembourg, 1989: pp. 85-105.
  18. Wallston KA, Wallston BS, DeVellis R. Development of the Multidimen¬sional Health Locus of Control (MHLC)Scales. Health Educ Monogr 1978; 6(1): 160-170.
  19. Wallston KA. Wallston BS. Who is re¬sponsible for your health? The con¬struct of Health Locus of Control. In Sanders GS, Suls J, Eds. Social Psy¬chol¬ogy of Health and Illness. Lawer¬ence Erlbaum Associates, New Jer¬sey. 1982; pp. 65-95.
  20. Rodin J. Aging and health: effects of the sense of control. Science. 1986;  233(4770): 1271-1276.
  21. Macrodimitris SD, Endler NS. Coping, control, and adjustment in Type 2 diabe¬tes. Health Psychol. 2001; 20(3): 208-216.
  22. Surgenor LJ, Horn J, Hudson SM, Lunt H, Tennent J. Metabolic control and psy¬chological sense of control in women with diabetes mellitus. Alterna¬tive con¬siderations of the relationship.  J Psy¬chosom Res. 2000; 49(4):  267-273.
  23. Aikens JE, Wallander JL, Bell DS, McNorton A. A nomothetic-idio¬graphic study of daily psychological stress and blood glucose in women with type I diabetes mellitus. J Behav Med. 1994; 17(6): 535-548. 
  24. Bunting BP, Coates V. Stability and pre¬dictors of blood glucose levels: An in¬tra- and inter-individual analysis. Psy¬chol Health Med. 2000; 5(3): 251-258.
  25. Kneckt MC, Syrjala AM, Knuuttila ML. Locus of control beliefs predicting oral and diabetes health behaviors and health status. Acta Odontol Scand. 1999; 57(3): 127131.
  26. Ferraro LA, Price JH, Desmond SM, Roberts SM. Development of a Diabe¬tes Locus of Control Scale. Psychol Rep. 1987; 61(3): 763770.
  27. Toobert DJ, Glasgow RE. Assessing Diabetes Self-Management: The Sum¬mary of Diabetes Self-Care Activities Questionnaire. In Bradley C, Eds. Hand¬book of Psychology and Diabetes.  Harwood Academic Publishers. Chur, 1994: pp. 351375.
  28. DCCT Research Group The effect of intensive treatment of diabetes on the de¬velopment and progression of long-term complications in insulin-depend¬ent diabetes mellitus. N Engl J Med. 1993; 329(14): 977986.
  29. Jones EG, Kay M. Instrumentation in cross-Cultural Research. In Downs FS, Eds. Readings in Research Methodol¬ogy. 2nd ed.  Lippincott Williams & Wil¬kins. USA. 1999. pp. 246-248
  30. Toobert DJ, Hampson SE, Glasgow RE. The Summary of Diabetes Self-care Activities Measure. Diabetes Care. 2000; 23(7): 943950.
  31. Kelly K. Patient compliance: the final frontier of diabetes care. Practical Dia¬betol. 1995; 14(1): 20-23.
  32. Hurley AC. Shea CA. Self-efficacy: strat¬egy for enhancing diabetes self-care. Diabetes Educ. 1992; 18(2): 146-150.
  33. Cerkoney KA. Hart LK. The relation¬ship between the health belief model and compliance of persons with diabe¬tes mel¬litus. Diabetes Care. 1980; 3(5): 594-598.
  34. Hutton SL. Perceptions of control and social cognitive theory: understanding ad¬herence to diabetes treatment regi¬men. [MS thesis]. Department of Health and Exercise Science, Wake For¬est University, North Carolina, USA: 2002.
  35. Buckelew SP, Shutty MS, Hewett J, Landon T, Morrow K, Frank RG. Health locus of control, gender differ¬ences and adjustment to persistent pain. Pain. 1990; 42(3): 287-94.


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