Magnitude of overweight and associated factors among type 2 diabetes mellitus patients at Mekelle public hospitals, Tigray, Ethiopia: a cross-sectional study

Objective To assess magnitude of overweight and associated factors among type 2 diabetes mellitus patients at Mekelle public hospitals, Tigray, Ethiopia. Results A total of 365 participants were enrolled in this study. One hundred ninety-eight (54.2%) of the participants were males and 288 (78.9%) of the study participants were from an urban residence. In this study 161 (44.1%) and 12 (3.3%) of the study subjects were alcohol consumers and smokers respectively. Besides, 166 (45%) of the study participants had poor dietary intake and around 302 (82.7%) had low level of vigorous physical activity. The proportion of individuals who were overweight using body mass index as a measure was 149 (40.8%) and the proportion of individuals who had central obesity using waist circumference as a measure was 194 (53.2%). The magnitude of overweight among study participants from urban residence and alcohol consumers was 138 (92.6%) and 93 (62.4%) respectively. Residence area, alcohol consumption, physical activities, central obesity and dietary intake were the determinant factors for overweight among type 2 diabetes mellitus patients.


Introduction
Globally, more than 1.9 billion adults aged 18 years and above were overweight in 2016. Of these, over 650 million adults were obese [1]. In Sub-Saharan African (SSA) countries the magnitude of overweight is increasing at an alarming rate [2]. This is due to rapid urbanization, dramatic lifestyle changes and high prevalence of child hood stunting [3]. Overweight has been an issue in developed countries for the past years. However, currently, it has gained attention in developing countries as an issue that needs to be addressed [4]. Overweight in people with diabetes could induce increased thrombogenic factors, cardiovascular disease and raised blood pressure. It also interferes with the treatment of hyperglycemia and diabetes-related complications [5,6].
In Ethiopia, magnitude of overweight is increasing among type 2 DM patients. However, data on overweight of type 2 DM patients is limited because priority has always been given to under nutrition and communicable diseases [7,8]. Besides, previous studies predominantly relied on body mass index (BMI) as measure of overweight. However, our study used both BMI and waist circumference to measure overweight. Therefore, the aim of this study was to assess magnitude of overweight and associated factors among type 2 DM patients. hospitals, Tigray, Ethiopia. All type 2 DM patients who were available at the time of data collection period were included and patients who had severe illness or physical disability, pregnant mothers and patients with edema were excluded from this study.

Sample size determination and sampling technique
A single population proportion formula was used. The estimated proportion of overweight among type 2 DM patients was 31.5% [8]. Accordingly, the required sample size (n) was estimated with a confidence level of 95%, 5% margin of error and by adding 10% non-response rate the final sample size was 365.
Systematic random sampling method was used to select the study participants from a total of 2442 type 2 DM patients who were on treatment follow up in Mekelle public hospitals. To select the required sample size the total sample size was proportionally allocated to the three public hospitals. Accordingly, the list of the patients was taken from the follow up unit of the three public hospitals and sampling frame was developed. Then the first study subject was randomly selected from the sampling frame by using lottery method and based on the sampling interval (k = 6) every six interval was selected from the sampling frame. Finally, 365 of patients with type 2 DM were included in our study.

Data collection tools and procedures
The tools for data collection include a portable Stadiometer, stretch-resistant tape meter and structured questionnaire. The questionnaire was composed of questions on socio-demographic data, behavioral and health-related factors, dietary factors and anthropometric measurement (weight, height and waist circumference).
The data was collected using a structured questionnaire through face to face interview and physical measurements of weight, height, waist circumferences using standardized techniques and calibrated equipment. Weight and height were measured with participants standing without shoes and wearing light clothing. Participants were standing upright with the head, shoulder, buttock, lower limb and heal of the foot touches the height board for height measurement. Waist circumference was measured midway between the lower rib margin and the iliac crest in the horizontal plane using a tape meter by following the standard procedure.

Data quality control
The questionnaire was initially prepared in English and translated to Tigrigna language then back to the English language. One day training was given on the objective of the study, instrument and data collection procedures by the principal investigator for the data collectors and supervisors. The weight measurement scale was checked if it is at zero before each measurement. Five percent of the questionnaire was tested before the actual data collection period outside of the study area. Data collectors were instructed to check the completeness of the instrument just after its completion. The principal investigator checked out the questionnaire for completeness each night. Moreover, the collected data were coded, cleaned and explored before analysis to check missing items and completeness of the collected data.

Operational definitions
Overweight BMI greater than or equals to 25 kg/m 2 .
Central obesity waist circumference greater than 88 cm for females and greater than 102 cm for males was considered as having abdominal obesity.
Low level of physical exercise individual activity less than 150 min per week was considered as low level of physical activities.
Adequate level of physical exercise individual activity above 150 min per week was considered as adequate level of physical activities.
Dietary intake level of dietary intake was determined based on dietary factors questionnaire. Six items were asked and based on the mean value of those questions individuals who score below the mean value were classified as poor and those who score above the mean value were classified as good dietary practices.

Data processing and analysis
The collected data were entered and cleaned using Epidata manager. Two items of dietary questions were reversely coded to explain total score to be interpreted as higher scores meaning better outcomes. Then it was exported to SPSS version 21 for statistical analysis. Descriptive statistics were computed using the frequency table and numerical summary measures. Binary logistic regression was done to determine the magnitude, direction and strength of association between a set of independent variables and the outcome variable at p < 0.25 significance level. Then those variables that were significant at p < 0.25 with the outcome variable were selected for multivariable analysis. Odds ratio with 95% confidence level was computed and significant association was declared at p-value < 0.05. Finally, the result was presented using text and tables.

Socio-demographic characteristics
A total of 365 participants were enrolled in this study. One hundred ninety-eight (54.2%) of the participants were males. Two hundred seventy (74%) of the study subjects were Orthodox followers. Besides, 288 (78.9%) of the study participants were from an urban setting and 291 (79.7%) were married (Table 1).

Behavioral factors and dietary intake of type 2 DM patients
Out of 365 respondents, 161 (44.1%) and 12 (3.3%) of the study subjects were alcohol consumers and smokers respectively. About 247 (67.7%) of the study subjects had a habit of walking on their daily living and 302 (82.7%) had low level of vigorous physical activity. In our study 199 (55%) of the study participants had good dietary intake and 166 (45%) had poor dietary intake. Of these, 333 (91.2%) had got nutritional education from different sources and 32 (8.8%) individuals didn't have nutritional education from any sources.

Magnitude of overweight
The magnitude of overweight among type 2 DM patients using BMI as a measure was 149 (40.8%) [95% CI (35.7, 46)] and by using waist circumference as a measure 194 (53.2%) of the study subjects had central obesity (Table 2).    (Table 3).

Discussion
In this study, the overall magnitude of overweight was 40.8% [95% CI (35.7, 46)]. This is almost similar to the study done in Addis Ababa, and Hosanna [7,8]. However, it is lower than the study done in India, Nepal and Bahrain [9][10][11]. This difference might be due to variation in socio-demographic factors, lifestyle, and economic status. In this study, using waist circumference as an indicator yielded the highest magnitude of obesity compared to using BMI. By using waist circumference as a measure 53.2% of the study subjects had central obesity that is higher as compare to the general obesity (40.8%). In general, this finding indicates that using BMI alone underestimate the magnitude of overweight or obesity.
Dietary intake was also the other variable that had significant association with overweight among type 2 DM patients. This is in line with the study done in Addis Ababa, Ethiopia [7]. It is also supported by study done in South Africa [12]. The reason might be due to rapid nutrition transition in developing countries and lack of nutritional education. There was also a statistically significant association between overweight and physical activities. This finding is in line with a study done in South Africa, Yemen, and Ghana where physical activity was significantly associated with overweight [12][13][14]. This might be due to high in sedentary behavior and poor motivation to physical exercise.
Residence area was the other variable that had a significant association with overweight in this study. Being from urban residence had 3.4 times odds of being overweight. The possible reason might be due exposure of urban population to unhealthy lifestyle, high proportion of urban study subjects in the current study and participants from rural area were more physically active. It is also showed that duration of diabetes after diagnosis was significantly associated with overweight. However, it contradicts with the finding reported from Yemen and Kenya which reports, the occurrence of overweight decreases with the duration of DM after diagnosis [13,15]. So, this contradicting issue needs further investigation. Previous studies reported that being female associated with overweight however in this study sex had no significant association with overweight [9,10]. This might be due to variation in socio-demographic factors.

Conclusion and recommendations
The magnitude of overweight was high among type 2 DM patients. The determinant factors were residence area, alcohol consumption, low level physical activities, duration of DM, central obesity and dietary intake. Using waist circumference in conjunction with BMI would be useful for better diagnosis and early detection of overweight among type 2 DM patients. Researcher should have to investigate perceived barriers to regular physical activity among type 2 DM patients.

Limitations of the study
• There might be recall bias among respondents answering questions related to dietary intake of the week, time spent for doing physical activity and sitting/reclining on a typical day. • Nutritional knowledge and genetic susceptibility of the respondent to overweight was not considered.