DIABETES PREVALENCE: A COMPARISON BETWEEN URBAN AND RURAL AREAS OF BANGLADESH

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1 E S Scholars T Knowledge is Power September 2012 Volume 1, Issue 4 Article #10 IRJALS Research Paper ISSN: DIABETES PREVALENCE: A COMPARISON BETWEEN URBAN AND RURAL AREAS OF BANGLADESH Tasneem Imam * and Md Belal Hossain ** * Lecturer in Statistics, Dept. of Agricultural Economics and Social Sciences, Chittagong Veterinary and Animal Sciences University, Chittagong. imam.tasneem@yahoo.com ** Assistant Professor, Dept. of Statistics, Biostatistics & Informatics, University of Dhaka, Dhaka bjoardar2003@yahoo.com Abstract Diabetes as a disease has increased in an alarming way that has created a serious threat to public health globally. As per available data 346 million people worldwide are suffering from diabetes that has not only created bad effect on human health but also on different aspects of their lives. This paper sharply attempts to establish the relationship of diabetes prevalence with the urban and rural areas of Bangladesh. Data of patients have been collected from the register of Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM), which is a reliable health institution dealing mainly with diabetes and resulting other diseases. A very clear link has been established between blood sugar level in both urban and rural areas and all other factors taken into account for human-being developing Diabetes. In the year 2000 Diabetic patients' data were compiled for age-range 40 years. Men were more prone to developing this disease as compared to women. Patients whose either or both the parents were diabetic experience diabetes more than the others. The more educated a person is and the more annual income one has, raises the likelihood of contracting Diabetes. The disease is more common for people who are mostly physically inactive. Higher blood pressure and excess body weight also contribute to incidence of Diabetes. This whole picture is very much prominent in the urban areas compared with the rural ones. Introduction Diabetes is a chronic disease that occurs when the pancreas does not produce enough insulin, or when the body cannot effectively use the insulin it produces. Question arises what is insulin? Insulin, a hormone produced in the islets of langerhans in pancreas, is the major metabolism and lack of insulin is, perhaps, 114

2 the major reason in developing diabetes. Hyperglycemia, or raised blood sugar, is a common effect of uncontrolled diabetes and over time leads to serious damage to many of the body's systems, especially the nerves and blood vessels. But the good thing is diabetic patients can have a normal life under proper medical treatment and proper diet/ regimen. Besides lack of insulin, there are supposed to be some demographic, socio-economic and environmental factors that help in developing diabetes such as age, sex, genetic issue, education, income, occupation, weight, height, lack of physical work and many more. Diabetic patients often show the symptoms of copious urination, severe thirst, immoderate hunger, weight loss etc. Generally, a glucose tolerance test (GTT) is used to diagnose diabetes. The procedure is to measure the blood glucose after fasting and then at 2 hours interval after a 75gm glucose consumption. Table 1 summarizes the 2006 WHO recommendations for the diagnostic criteria for diabetes and intermediate hyperglycemia. Table 1: Diagnostic criteria for diabetes and intermediate hyperglycemia Glucose tolerance test Fasting plasma glucose 2 hour plasma glucose* Impaired Fasting Glucose (IFG) 6.1 to 6.9mmol/l (110mg/dl to 125mg/dl) (if measured) <7.8mmol/l (140mg/dl) Impaired Glucose Tolerance (IGT) Diabetic <7.0mmol/l (126mg/dl) 7.0mmol/l (126mg/dl) 7.8 and <11.1mmol/l (140mg/dl and 200mg/dl) 11.1mmol/l (200mg/dl) * Venous plasma glucose 2 h after ingestion of 75g oral glucose load. * If 2 h plasma glucose is not measured, status is uncertain as diabetes. Related Research A study from Bangladesh describes an increased prevalence of type 2 diabetes in an affluent population when corrected for other major diabetes risk factors. Seven studies investigating the relation between the incidence of type 1 diabetes and socioeconomic status have generally found little evidence of a relation. That study showed, in either urban or rural areas, the highest prevalence of Non Insulin Dependent Diabetes Mellitus (NIDDM) was observed among the rich, and the lowest prevalence was observed among the poor socioeconomic classes. The rural rich had much higher prevalence of Impaired Glucose Tolerance (IGT) than their urban counterpart (16.5 vs. 4.4%, CI ). Increased age was an 115

3 important risk factor for IGT and NIDDM in both rural and urban subjects, whereas the risk related to higher Body Mass Index (BMI) and waist-to-hip ratio (WHR) was less significant in rural than urban subjects. The urban subjects had no excess risk for NIDDM. In contrast, an excess risk for glucose intolerance (2-h BG > or = 7.8 mmol/l) was observed in the rural subjects. Adjusting for age, sex, and social class, the prevalence of NIDDM among urban subjects did not differ significantly from that among rural subjects. Increased age, higher socioeconomic class, and higher WHR were proven to be independent risk factors for glucose intolerance in either area. Women with type 2 diabetes face a higher risk of cardiovascular disease than do men with type 2 diabetes according to Abu et al (1997). Obesity, physical inactivity, smoking, and low birth weight have all been described as risk factors for type 2 diabetes. In 1994, Health Survey of England pointed that in Western societies these factors are associated with low socioeconomic status. Here an attempt has been made to study the association between prevalence of diabetes of the patients of BIRDEM with urban and rural areas of Bangladesh. Materials and Methods A set of follow-up data from the register of the year 2000 of BIRDEM was collected for our study. At the registration of patients each one of them was requested to face 149 points in a questionnaire. Then the responses were compiled by the physicians including sex, marital status, BMI, age at diagnosis, pulse, blood pressure, diet, result of GTT, education, occupation, income, living area, full address at first visit etc. Data have been updated at each visit to record the current treatments. A list of patients which included both diabetic and non diabetic patients was generated by computerized searches of diagnostic lists. The individual case records were then analyzed by the researcher to confirm the diagnosis of diabetes and record the patient characteristics. BIRDEM record sheet contains about 89 variables from which we have selected a few variables for our study. However, we are interested in comparing a few selected demographic variables (age, sex, marital status and family history), socio-economic variables (education, annual income, physical exercise) and some clinical variables (BMI, systolic blood pressure (SBP) and diastolic blood pressure (DBP)) in the urban and rural areas of Bangladesh.. We employ bivariate analysis to examine the association between the selected variables with blood glucose level. The living area of the patients is a qualitative variable having three categories: rural, urban and semi-urban from which urban and semi-urban both the categories merged into one category to make area a dichotomous variable. On the other hand, a patient whose blood glucose level after 75gm glucose consumption is greater or equal to 11.1mmol/liter is considered as confirmed diabetic and those less than 11.1mmol/liter is considered as controlled diabetic. Some exploratory studies will also be used to know the association between variables in context of urban and rural areas. Graphs have been also used for the comparison between variables. Chi-square multi dimensional analysis (Friedman test) is done to test the significance among the variables. To see the associations between the variables we have used STATA

4 (reference). The demographic variables we considered here are age, sex, marital status and family history. From them, age is the first variable that has been recorded at the first registration. As we know, here it is a continuous variable having two categories- less than 40 years and greater than or equals 40 years and can be used directly in the study. Sex is a dummy variable with two categories- male and female. Marital status is a qualitative variable including the categories-married, unmarried, divorced and separated. To see the trend the last three groups are merged into one group named others. A genetic factor, family history plays an important role to develop diabetes. The BIRDEM data set contains two variables family history of father and family history of mother. For the convenience of analysis both the variables are merged and named by a new variable family history of father and mother having three categories either or both the parents were diabetic, both the parents were non-diabetic and unknown. The socio-economic variables have also been taken into account in our study. Education is one of them which has been categorized into two groups- Up to secondary and Secondary+. Income is also a factor in developing diabetes which has three categories one is of those patients whose income are less than 10,000tk, one of those with annual income (10,000-49,999) Tk and the rest belong to the third group. Physical exercise is a dummy variable coded as yes and no. Mentioning about the clinical variables, in many studies, BMI is one of the strongest predictors of diabetes, and previous studies have shown that changes in BMI foreshadow changes in diabetes. The measurement used most often to quantify body fat is BMI. It is relatively easy to calculate (weight in kilograms divided by the square of the height in meters); it has defined risk categories (overweight, BMI 25 kg/m 2 ; and obese, BMI 30 kg/m 2 ), and it is closely correlated with body fat in most people. It is not a perfect measure, however. BMI does not distinguish between fat mass and lean mass and, therefore, does not provide an accurate indication of body fat in extremely muscular individuals or people who have lost significant muscle mass. In addition, BMI may not be a sensitive indicator of the health risks associated with moderate weight gain (10 20 lb) in individuals that fall within the normal BMI range. Despite these limitations, BMI can be a reliable and valid measure for identifying adults at increased risk of overweight- and obesity-related morbidity and mortality (Cynthia et al, 2004). Here, BMI is divided in to three categories- Lean i.e. BMI < 19.4 kg/m 2 ; Normal i.e. BMI from 19.4 to 24.9 kg/m 2 ; Overweight & Obese i.e. 25 kg/m 2. Blood pressure level is considered to be a clinical variable in this study. Here, Systolic blood pressure and Diastolic blood pressure both have three categories such as, low (less than 100 for systolic and less than 70 for diastolic), normal ( for systolic and for diastolic) and hypertensive (more than 140 for systolic and more than 90 for diastolic). Results There were persons registered in the year of 2000 at BIRDEM where 227 cases were missing. That is why, we have considered persons in our study out of which (80.12%) persons were identified as 117

5 confirmed diabetes and 2940 (19.88%) persons were at controlled level. Patients registered from the urban or semi-urban areas were 9445 (63.87) where as 5344 (36.13%) patients were from the rural areas. Before comparing the variables in terms of areas, it is important to know the frequency distribution of Area-Blood glucose level composition so that it can give the idea about the frequency of diabetic patients in urban and rural areas of Bangladesh. Table 2: Area-Blood glucose level composition Blood Glucose Level Controlled Diabetic Confirmed Diabetic Total Area ( <11.1 mmol/l) ( 11.1 mmol/l) Urban/Semi-urban 1642(11.10) 7803(52.76) 9445 Rural 1298(8.78) 4046(27.36) 5344 All It is observed from Table 2 that, the percentage of confirmed diabetic patients is pretty much higher in the urban/semi urban areas as compared to the rural areas. The reason for this is manifold which can be related to the total way of life of both rural and urban people. The disease can be related to education, occupation, body mass index, living condition etc including the mental stress. Urban life is more complicated and stressful when compared with the rural ones. Therefore the urban people with stress, high ambition, competitive life, spatial distribution pattern are all possible dominant ones that can also be treated as causal factors of this disease. Causes are multiples, but we have chosen a few important variables to understand this issue. The first one is age where 70.89% of the total patients are at or more than of 40 years and 29.11% are below 40 years. Sex is considered to be another causal factor in developing diabetes. In our data, out of patients, 56.3% were males and the rest are female. Marital status is also another factor considered in our study. Here, 87.7 % of the total patients are married while 12.3% are others. Table 3 discovers the factors influencing diabetes in context of urban and rural areas of our country. 118

6 Table 3: Cross tabulation of age, sex, marital status, family history Vs blood glucose level and area Blood Glucose Level After 75gm Glucose Consumption at Registration Controlled Diabetic ( <11.1 mmol/l) Confirmed Diabetic ( 11.1 mmol/l) Demographic Variables Urban(%) Rural(%) Urban(%) Rural(%) Age <40 469(3.17) 469(3.17) 2246(15.18) 1127(7.62) (7.93) 829(5.61) 5557(37.58) 2919(19.74) Male 1037(7.01) 849(5.74) 4058(27.44) 2376(16.07) Sex Female 605(4.09) 449(3.04) 3745(25.32) 1670(11.29) P- value 0.00** 0.00** Marital Status Married 1443(9.76) 1048(7.09) 6977(47.17) 3495(23.63) Unmarried 94(0.64) 167(1.13) 238(1.61) 237(1.60) Others 105(0.71) 83(0.56) 588(3.98) 314(2.12) 0.00** Either or both 150(1.01) 76(0.51) 614(4.15) 205(1.39) Family parents diabetic history Both parents nondiabetic 1130((7.64) 953(6.44) 5367(36.29) 2885(19.51) 0.00** Unknown 362(2.45) 269(1.83) 1822(12.32) 956(6.46) ** highly significant at 1% level of significance Table 3 reveals that density of the patients in the year of 2000 is higher in the age group ( 40) that is in the middle age and it is been seen that confirmed diabetic patients are much higher in the urban areas specially in the middle age group. As far as the factor sex is concerned, we can see that diabetes is likely to develop among the males compared to the rural one and this picture is more reflected in the urban/semi- urban areas i.e % of the total patients with diabetes were from the urban/semi- urban areas while 19.74% were from the rural areas. But we cannot say that males tend to develop diabetes more than female as in our country female are usually deprived to proper food, health care education etc and may not register due to socio-economic issues. Anyway, we are more interested in comparing this factor in urban and rural areas of Bangladesh. Study reveals that married persons tend to have diabetes than the others which is quite obvious as we have already seen that people aged at or more than 40 years have the highest frequency of developing diabetes and in our country people get married before middle age generally, but prevalence of diabetes among the married people is remarkably higher in the 119

7 urban/semi-urban areas that supports our hypothesis. Genetic issues have been considered here as a factor and from the table, we found that out of confirmed diabetic patients, 5.54% belong to the first group i.e. either or both parents diabetic where 4.15% are urban patients. But it is not wise to say that diabetes occurs among the patients whose parents are non- diabetic though this data indicate the other picture. In fact, many studies revealed that children whose either or both parents are diabetic tend to develop this disease at any time of their life span. Here, we can see that, 23.06% of the total patients are unaware of their parents diabetic status. 120

8 The findings can also be presented graphically as below: Figure 1: Bar diagram of area by blood glucose level by age. Figure 2: Bar diagram of area by blood glucose level by sex Figure 3: Bar diagram of area by blood glucose level by marital status Figure 4: Bar diagram of area by blood glucose level by family history 121

9 Not only the demographic variables, but there are also some socio-economic variables that help in developing diabetes. A study revealed that prevalence of type 2 diabetes would be inversely related to socioeconomic status (V Connolly, N Unwin, P Sherriff, R Bilous,W Kelly,2000).In our study, a few variables have been taken into account as education, annual income, physical exercise. Table 4: Cross tabulation of education, annual income, physical exercise vs blood glucose level and area Blood Glucose Level After 75gm glucose consumption at registration Controlled Diabetic Confirmed Diabetic p- value Socio-economic variables ( <11.1 mmol/l) ( 11.1 mmol/l) Urban(%) Rural(%) Urban(%) Rural(%) Up to 579(3.92) 583(3.94) 2963(20.04) 1846(12.48) Education secondary 0.00** Secondary+ 1063(7.19) 715(4.82) 4840(32.73) 2200(14.88) Annual income ( in taka) <10, (0.78) 257(1.74) 416(2.81) 371(2.51) 10,000-49, (3.46) 635(4.29) 2062(13.94) 1973(13.34) 50, (6.86) 406(2.75) 5325(36.01) 1702(11.51) 0.00** Physical exercise Yes 481(3.25) 401(2.71) 1604(10.85) 1017(6.87) No 1161(7.85) 897(6.07) 6199(41.92) 3029(20.48) 0.00** ** highly significant at 1% level of significance Table 4 indicates that education plays a positive role in developing diabetes and this picture is more prominent in urban areas (32.73% of total patients). Income is also an important causal factor of diabetes which can be seen from table 1.3 that reveals 36.01% of the total patients in urban areas with higher annual income tend to develop diabetes more than the rural ones. Physical exercise is also a very important factor in developing diabetes. Generally, sedentary workers are more likely to develop diabetes than the ambulatory works People living in urban areas are to peruse different types of occupation. Nature of occupation varies so the occupational environment. These do contribute to this disease, for example, people who are working in sitting on chairs having many facilities, have less time to move. That is why they get this disease at early age while persons living in the rural areas are mostly engaged in ambulatory jobs and so they are less affected because of their physical movements related with their occupations. Table 1.3 reveals a higher number of sedentary workers get this disease than the ambulatory workers; 20.48% of the sedentary diabetic patients belong to the rural areas while 122

10 around 41.92% of the sedentary diabetic patients were from the urban areas. Graphically it can be represented as follows: Figure 5 Bar diagram of area by blood glucose level by education level Figure 6 Bar diagram of area by blood glucose level by annual family income Figure 7 Bar diagram of area by blood glucose level by physical exercise Some clinical variables also contribute in developing diabetes. In our study, a few important clinical variables have been chosen in order to compare between urban and rural areas of Bangladesh which are presented in the table

11 Table 5: Cross tabulation of Body mass index, Systolic blood pressure, Diastolic blood pressure vs blood glucose level and area Blood Glucose Level After 75gm glucose consumption at registration Clinical Variables Controlled Diabetic ( <11.1 mmol/l) Confirmed Diabetic ( 11.1 mmol/l) P Urban(%) Rural(%) Urban(%) Rural(%) value Lean 226(1.53) 554(3.75) 695(4.7) 1020(6.9) Body mass Normal 854(5.77) 539(3.64) 3842(25.98) 2075(14.03) 0.00** index Overweight & Obese 205(1.39) 562(3.8) 3266(22.08) 951(6.43) Systolic blood Low 65(0.44) 168(1.14) 187(1.26) 237(1.61) pressure Normal 1461(9.88) 1068(7.22) 7052(47.68) 3560(24.07) 0.00** Hypertensive 116(0.78) 62(0.42) 564(3.82) 249(1.68) Diastolic blood Low 113(0.76) 222(1.50) 310(2.10) 359(2.43) pressure Normal 1412(9.55) 1031(6.97) 6847(46.30) 3482(23.54) 0.00** Hypertensive 117(0.79) 45(0.30) 646(4.37) 205(1.39) ** highly significant at 1% level of significance Table 5 reveals higher number of diabetic patients with overweight & obesity in the urban areas( 22.08% of the total patients) comparing with the rural areas (only 6.43% of the total patients). The reason may be the unavailability and if available, then non affordability of the rural people to consume ay type as well as any quantity of food. Here, in case of systolic blood pressure and diastolic blood pressure variables, we can see that patients with normal blood pressure have the higher frequency to develop diabetes and it is highest in the urban areas. Among the hypertensive patients, 813 systolic hypertensive patients experienced diabetes out of which 564 belonged to urban areas and 851 patients with diastolic hypertension experienced diabetes out of which 646 were from the urban areas. Conclusion In conclusion, it has to be mentioned that, this study based on BIRDEM data considered the concentration of blood glucose level after two hours of 75g oral glucose consumption which was compared in urban and rural areas in terms of some factors such as age, sex, marital status, family history, education, annual income, physical exercise, BMI, systolic and diastolic blood pressure. As, discussed above, found a highly significant relationship between blood glucose level of patients living in both urban and rural Bangladesh with all the variables or factors considered here in developing diabetes, but it is significantly higher in the urban areas compared with the rural 124

12 ones as we found p value< for all the cases in our study. This trend can be related to the differential occupations, working conditions and also the motivation for better living which are absent in the rural areas. Diabetic patients in the year of 2000 mostly were obtained in the age group 40 years. Males were more likely of developing diabetes than females. In case of socio economic variables, highly educated person with high annual income had the tendency to experience diabetes. This do not certainly mean that the educated and highly paid persons suffer from diabetes more than the less educated people, but it indicates that less educated and with less income people were not aware of this disease. People with no physical work tended to develop this disease. Obesity or overweight, growing blood pressure level also indicates positive signs in developing diabetes. This trend was significantly higher in the urban areas of Bangladesh. In the end, we know Diabetes is a group of metabolic disorders due to relative insulin deficiency which can cause serious health complications including heart disease, blindness, kidney failure, and lower-extremity amputations. It is quite shocking that 51 per cent of people in Bangladesh are unaware that diabetes exists. The lack of knowledge highlights the major health problems faced by people in Bangladesh, and the immense knowledge gap that needs to be filled to increase diabetes awareness in the country. The number of diabetic patients is annually growing at a rate of three percent in the country and if the present rate continues, the number of diabetics will double to 10.4 million by This information was obtained from a recent seminar titled 'Role of Insulin Glargine in Diabetes Management. Terming diabetes as a silent killer of this century, public health strategies to limit this increase are urgently recommended. 125

13 References: 1. M. A. SAYEED, L. ALI AND MZ. HUSSAIN, Diabetes Care, 20, 551, Definition and diagnosis of diabetes mellitus and intermediate hyperglycemia. Report of a WHO/IDF Consultation, F.B HU, R.M. VAN DAM AND S.LIU, Diabetologia, 44, 805, RJ. KUCZMARSKI, MD. CARROL, KM. FLEGAL AND RP. TROIANO, Obes Res, 5, 542, EB. RIMM, J. CHAN AND MJ. STAMPFER,. BMJ,310, 555, JA MARSHALL, S HOAG AND S SHETTERLY, Diabetes Care, 17, 50, N. CHATURVEDI AND PM. MCKEIGUE, J Epidemiol Community Health, 48, 107, N. ROBINSON, CE. LLOYD AND LK STEVENS, Diabet Med, 15, 205, FA.MAJEED, DG.COOK AND J POLONIECKI, BMJ, 310, 1373,