Risk factors for type 2 diabetes mellitus: An urban perspective

INTRODUCTION

In 2008, an estimated 347 million people in the world had diabetes and the prevalence is growing, particularly, in low- and middle-income countries. Diabetes is fast gaining the status of a potential epidemic in India, with 69.2 million people living with diabetes (8.7%). Of these, more than 36 million people remained undiagnosed.^[1] According to Wild et al., the prevalence of diabetes is predicted to double globally from 171 million in 2000 to 366 million in 2030. It is predicted that by 2030 diabetes mellitus may afflict up to 79.4 million individuals in India.^[2,3] The current scenario of diabetes in India is likely to worsen in the coming decade. The greatest numbers of people with diabetes are between 40 and 59 years of age.^[4]

Indians characteristically have increased insulin resistance, greater abdominal adiposity (higher waist circumference despite lower body mass index), higher prevalence of impaired glucose tolerance, contributing to a greater risk of developing disease at a relatively younger age. The epidemiological transition, economic boom, physical inactivity, trendy dietary patterns, and environmental factors also add to this risk.^[5] By adopting urbanized lifestyle like changing food habits, sedentary working pattern and stress, urban poor the known vulnerable group are at higher risk for diabetes mellitus.^[6]

As literature review does not reveal major studies from Pune area, to address this demand, the present study was undertaken with the objective of determining prevalence of diabetes mellitus and its association with various risk factors.

METHODOLOGY OF STUDY

A community-based cross-sectional study was conducted for a period of 1 year (2013–2014) in three randomly selected municipal wards of Pune city to which the field practice area of Urban Health Training Center of private Medical College, Pune, provides services. From each of these three wards, three areas namely Joshiwada (349), Ganjwewada (177), and Mangwada (243) with total population of 769 were randomly selected. Using prevalence of type 2 diabetes mellitus 18.6%^[7] and considering allowable error of 20% by applying formula 4 pq/L², estimated sample size was 438. From each area, the study subjects selected were 199,100 and 139 from Joshiwada, Ganjwewada, and Mangwada, respectively. A total of 13 study subjects were nonrespondents, therefore, sample collected was 425.

RESULTS

DISCUSSION

The total prevalence of diagnosed cases of type 2 diabetes mellitus found in this study was 9.88%. The prevalence below the age of 50 years was 9.19% and it was 15.66% in the age 50 years and above. Thus, the prevalence of diabetes mellitus increased with increase in age which was found to be statistically significant (P < 0.05) [Table 1]. Similar findings were noted by authors in India, as well as outside.^[6,9-17] Almost three times increase in the prevalence of diabetes mellitus after the age of 60 years (40–60 years – 5.8% vs. above 60 years – 16.66%) were found by Ahmad et al.^[18]

In the current study, the prevalence of diabetes mellitus is more in males (13.75%) compared to females (7.5%) which was found statistically significant (P < 0.05) [Table 1]. Gikas et al.^[11] and Shrestha et al.^[12] reported similar findings like the current study, while in the population-based studies were done by Rao et al.^[6] and Arora et al.^[17] have reported that the prevalence was higher in females.

The association between low educational status and diabetes mellitus was found to be statistically significant in the present study (P < 0.05) [Table 2]. Gikas et al.,^[11] Arora et al.,^[17] and Acemoglu et al.^[19] also found highest prevalence in illiterates with decreasing trends in better-educated people like the current study. Ramachandran et al.^[7] and Satman et al.^[16] reported a positive association of education with diabetes mellitus similar to our study; however, Ravikumar et al.^[15] found a negative association between education and diabetes mellitus.

There was no statistically significant association between diabetes mellitus and socioeconomic class (P > 0.05) was seen [Table 2]. A study done by Satman et al.^[16] and Mohan et al.^[20] found higher prevalence in higher socioeconomic class like the current study and Shah et al.^[9] showed increasing socioeconomic strata was associated with diabetes mellitus, while Arora et al.^[17] reported higher prevalence in lower and upper class compared to upper middle class.

In the current study, although total prevalence of diabetes was found maximum in males, occupation wise homemakers showed higher prevalence of diabetes mellitus than any other occupation. This could be due to homemakers tend to have less outdoor activities along with the traditional less active lifestyle which may be responsible for a higher prevalence of diabetes mellitus in them [Table 2]. The highest prevalence in homemakers (9.9%) followed by unemployed and retired personnel (9.6%) was also noted by Arora et al.^[17] and Ahmad et al.^[18] in their study.

The association of family history of diabetes mellitus and diagnosed cases of diabetes mellitus was proved highly significant (P < 0.001) [Table 3]. Many studies noted similar findings like our study.^{[6,7,11,14-18]} Mohan et al.^[20] showed higher prevalence of diabetes mellitus among subjects with both parents diabetic (55%) compared to those with one parent diabetic (22%).

Doing less physical activity is one of the risk factors for diabetes mellitus which was reported in the current study; however, the association of physical activity with diabetes was not significant (P > 0.05) [Table 3]. Tiwari et al.^[10] reported similar findings, i.e., those involved in mild activity were having diabetes mellitus and the difference was not significant. Shah et al.,^[9] Ahmad et al.,^[18] and Mohan et al.^[20] found less physical activity was significantly associated with diabetes mellitus and those subjects who performed moderate to light grade physical activity were having diabetes mellitus as compared to those who performed heavy physical activity.

The association between obesity and diabetes mellitus was found to be significant in the present study (P < 0.05) [Table 3]. This was supported by other studies done in India and other countries,^[6,11,14-20] while Shah et al.^[9] and Tiwari et al.^[10] did not find any association between BMI and diabetes mellitus.

Abdominal obesity commonly found in Indian population was more prevalent in our diabetic subjects also. A significant association between waist circumference and diabetes mellitus (P < 0.05) was found only in males [Table 3]. Similar results were noted by few authors.^{[6,7,10,15,20]} In addition to this a significant association between WHR and diabetes was found in males (P > 0.05) [Table 3]. Results were consistent with the study conducted by other authors.^[16,18,20]

CONCLUSIONS

This study determines association of various risk factors among diagnosed cases of type 2 diabetes mellitus. The association between increasing age, male sex, low educational status, obesity, waist circumference in males, and diabetes mellitus was found to be significant. It was observed that the association between family history of diabetes and WHR in males and diabetes mellitus was highly significant while there was no significant association found between physical activity, socioeconomic class, waist circumference, and WHR in females and diabetes mellitus. Thus, it is to conclude that nonmodifiable risk factors such as rising age, family history of diabetes mellitus, and modifiable risk factors such as lack of physical activity and central obesity were the most common factors found in diagnosed cases of diabetes mellitus. Hence, there is an impending need to conduct regular screening programs for early identification of high-risk group for diabetes mellitus and intensive health education programs focusing on the risk factors need to be carried out in the general population.