Predictors of Physical Activity in Type 2 Diabetic Patients Based on the Theory of Planned Behavior

Objective: Low physical activity is the fourth risk factor of death worldwide. Approximately 27% risk of diabetes is reduced by 150 minutes of moderate physical activity per week. The present study was designed to determine the predictors of physical activity promotion among type 2 diabetic patients. 
Materials and Methods: In this cross sectional study 320 patients with type 2 diabetes were included. The data collection tool was a questionnaire, consisting of three main parts; demographic characteristics, International Physical Activity Questionnaire (IPAQ) and Theory of Planned Behavior (TPB) theoretical constructs. Statistical software package SPSS (SPSS Inc version 20) used for all statistical analyses. To determine physical activity and predictive factors a series of logistic regression and bivariate correlations and descriptive analysis were computed. 
Results: About 57.5% of patients had moderate levels of physical activity. Significant positive correlation between subjective norms and attitudes toward behavior ( P -value= .0001) was seen. Significant positive correlations between behavioral intention and attitude toward the behavior ( P -value= .0001) and subjective norms ( P value= .0001) was observed. 
Conclusion: The results of the present study showed TPB based physical activity and demographic variable have key role in diabetic patient physical activity levels. To promote physical activity these findings can be used to design effective interventions.


Introduction
hysical inactivity is the fourth risk factor of death (1). In the Eastern Mediterranean region, 50% of women and 40% men are insufficiently active. In Iran 27.2% over 15 years old have low physical activity (2). Physical activity programs and support policies to increase physical activity levels among populations, World Health Organization suggests (3). About 27% reduced risk of diabetes by 150 minutes of moderate physical activity each week (2). Physical activity plays a key role in management and control of type 2 diabetes. Physical activity reduces insulin resistance. Also, physical activity increases the number of receptors and the sensitivity of cells to insulin concentrations in tissues, fat and weight loss lower blood pressure and increase physical fitness for type 2 diabetics. Especially women did not participate in physical activity, and they activity decreases with age increasing. So only 61-41% of 47-54 years old women have desirable physical activity (4)(5)(6)(7)(8). Theory of Planned Behavior (TPB): One of the most commonly utilized models to predict health behavior is the theory of reasoned action (9). TPB focus on theoretical constructs concerned with individual motivational factors as determinants of specific behavior. TPB assume the best predictor of a behavior is behavioral intention, which in turn is determined by attitude toward the behavior (evaluation associated with performing the behavior) and subjective norm (perceived social pressure to perform or not perform the behavior) regarding it. TPB is an extension of theory of reasoned action (TRA) and includes an additional construct: perceived control over performance of the behavior (10). The TRA and TPB, which focus on the constructs of attitude, subjective norm, and perceived control, explain most of the variance in behavior. Several meta-analyses and reviews confirm evidence. Meta-analyses support the predictive validity of the TPB model on variety of behavior (11) including physical activity and healthy eating habits (12)(13)(14)(15)(16)(17)(18). The present study was designed to determine the predictors of physical activity promotion among type 2 diabetic patients .

Materials and Methods
This cross-sectional study was conducted on 320 patients with type 2 diabetes who were referred to the diabetes center of Hamadan in 2013. The study subjects were selected among diabetic patients with simple random sampling method.
Anonymous self-reported questionnaire was used for data collection.
Two trained interviewers complete the questionnaires. They receive instructions for how to complete the same questionnaires. Interviewers introduced themselves to patients and explained the study aim and asked them to avoid writing their names on the questionnaires. All questionnaires preserved confidentially and stored for statistical analysis. Subjects entered the study with a willingness and written consent . The data collection tool was a questionnaire, consisting of three main parts, which were completed by the self-report method. The first part included the demographic characteristics of the participants such as age, gender, educational level, marital status, occupation, height, weight, and smoking history. The second part is the reliable and valid Persian form of the International Physical Activity Questionnaire (IPAQ). The questionnaire assessed the physical activity and classified it into three categories: low, moderate, and severe. TPB scale was designed based on a standard questionnaire and included 19 items under four constructs including (a) attitude; (b) subjective norms; (c) perceived behavioral control; (d) behavioral intention. Attitude include 7 items (3 items affective attitude,4 items instrumental attitude) were designed to measure attitude toward physical activity (e.g., "Doing 30 minutes of moderate physical activity at least 5 days a week would be"). The items were rated on a 5-point scale ranging from 1 (Very worthwhile)to 5 (Very worthless).Higher scores indicate more positive attitude to physical activity. These items were multiplicatively combined and averaged. The 7-items scale had Cronbach's alphas is 0.82, 0.54. About 4 items were designed to measure Subjective norms. A sample item is "I am under pressure from my family or friends to do 30 minutes of moderate physical activity at least 5 days a week." The items were rated on a 5-point scale ranging from 1 (Strongly disagree) to 5 (Strongly agree). The 4-item scale had Cronbach's alphas of 0.76. IRANIAN JOURNAL OF DIABETES AND OBESITY, VOLUME 11, NUMBER 4, WINTER 2019 Perceived behavioral control, a belief-based measure of PBC was employed. Control beliefs were assessed in relation to difficulty of physical activity, physical activity be up to me. The items were rated on a 5-point scale ranging from 1 (Strongly disagree) to 5 (Strongly agree). The 2-item scale had Cronbach's alphas of 0.71. Intention to use was measured with 2 items. The item "I expect to do 30 minutes of moderate physical activity at least 5 days a week The item rated on a 5-point scale ranging from 1 (Very unlikely) to 5 (Very likely) and how likely is it possible that you would make a decision to do 30 minutes moderate physical activity at least 5 days a week in the next month? Is too scaled. The 2-item scale had Cronbach's alphas of 0.60 (19).

Data analysis
Statistical software package SPSS (SPSS Inc version 20) used for all statistical analyses and an alpha level of .05 for all statistical tests. To determine physical activity and predictive factors a series of logistic regression and bivariate correlations and descriptive analysis computed.

Ethical considerations
This study was approved by the ethics committee of Hamadan University of Medical Sciences IR.UMSHA.REC.1397.930126169.

Results
This cross-sectional study was conducted on 320 patients with type 2 diabetes. The mean and standard deviation of age was 55 years and 11.87. About 61.9% of participants were in the category of 45 to 65 years old and 0.6% was fewer than 25 years old. Merely, 12.2% of participants were college graduates and most of them were illiterate or having only primary school education. Females were 71.6% of patients and 74.1% of them were married. Two hundred and ninety three (91.6%) patients were nonsmokers and 27 (8.4%) were smokers, which 20 of them were men (22% of men's). Self-employed patients, were 231 (72.2%) (Table1). Means and SD status of constructs; attitude, subjective norm, perceived behavioral control and behavioral intention (Table2). We used logistic regression model to predict physical activity intentions; attitudes and subjective norms were predictors of physical activity intention. (Table3) To predict physical activity using logistic regression model, behavioral intentions predict physical activity. Table 4 displays the relationship between demographic variables and model structure's (attitude, subjective norm perceived behavioral control and behavioral intention). The gender, age and employment status correlate with the attitude.

Discussion
The current study examined physical activity status based on TPB among diabetic patients as a prelude to the design of effective intervention strategies to promote their physical activity. Based on the findings of this study, most patients participate in the study had a moderate level of physical activity. The statistically significant relationship between attitudes (total) and behavioral intention with physical activity among diabetic patient was seen. Subjective norm, perceived behavioral control and physical activity correlation evaluated with Spearman's test, no significant correlation between these two showed. (17,(20)(21)(22), other studies have shown that levels of health indicators(body mass index, fasting blood glucose, blood lipids, blood pressure and heart rate) in patients with type 2 diabetes without intervention is usually abnormal. Thus increasing the above mentioned factors necessary to design studies and collect data (23,24). The results of the present study suggested that attitude toward physical activity between patients with type 2 diabetes intended meaning is strongly positive. The findings of this study is consistent by Boudreau et al (25) findings between patients with type II diabetes is (P-value< 0.01). Also in the study by Ghahremani et al. (22) physical activity is effective by 32.8% variance.
The findings showed that patient with a positive attitude to physical activity only have moderate activity this suggests that other factors play important role in behavior. In this study attitudes and demographic variables, gender, age and occupation were a statistically significant relationship.   explaining these differences. In this study, there were significant relation between behavioral intention and demographic variables such as age and occupation. No significant correlation reported between perceived behavioral control with intention and physical activity. Significant relation saw among perceived behavioral control and age. Ghahremani et al reported 8.32 variance of physical activity explained by PBC (22) .Fortier et al. reported that PBC significantly correlated with intention (28).

Conclusions
The results of the present study showed TPB based physical activity and demographic variable have key role in diabetic patient wellbeing. The relation of these variables with physical activity is important. To design effective intervention to promote physical activity these findings can used.