BMI, Physical Activity and Diabetes- A Case Control Study in a Rural Area of Kancheepuram district of Tamil Nadu.

Introduction:

Diabetes is one of the major public health problems in our country. Due to improved curative services and vaccination coverage infectious diseases had been controlled to a great extent. So now there is a shift in disease pattern from communicable to non communicable diseases. Among this diabetes stands first which causes both health and economic burden to the patients as well as country.

There were 62.4 million diabetics in India according to International Diabetes Federation in 2011and the number of deaths due to diabetes in the year 2011 was 983,000^[1]. India has the second largest number of diabetics next to China. The nationwide prevalence of diabetes is 9% and in southern cities it is as high as 20% ^[1] In western countries the onset of diabetes is at the age of 40's and 50's, but in our country the disease strikes much earlier. This will affect the economic growth and productivity of India.

The various known risk factors for diabetes such as family history, sedentary life style, age, gender, obesity, dietary habits, decreased physical activity. Several lifestyle factors affect the incidence of type 2 diabetes. Obesity and weight gain dramatically increase the risk ^[2,3] and physical inactivity further elevates the risk, independently of obesity ^{[2,3,4,5,6,7]}. Overweight or obesity was the single most important predictor of diabetes^[8]. Lifetime diabetes risk at 18 years of age increased from 7.6 to 70.3% between underweight and very obese men and from 12.2 to 74.4% for women. The lifetime risk difference is lower at older ages^[9]. The effect of BMI on diabetes risk is different for black and white Americans, with a larger risk for blacks than whites at low BMI and an equivalent risk for both groups at high BMI^[10]. For each 500-kcal increment in energy expenditure, the age- adjusted risk of NIDDM was reduced by 6 percent^[11]. Regular physical activity provides health benefits in individuals who have already expressed clinical Diabetes^[12]. Thus physical activity and BMI of an individual determines the occurrence of diabetes to a certain extent.

AIMS & OBJECTIVE:

To assess the association between physical activity, BMI and diabetes mellitus in a study population

METHODOLOGY:

Results:

Out of the 300 study subjects 248(82.7%) were men and 52(17.3%) were women. Out of these subjects cases and controls are equally distributed in both sexes.

Maximum number of participants was in the age group of 41-50 years followed by 51-60 years. (Table.1)

Out of the total study participants most of the participants (81%) do regular physical activities. Among the study participants 34% belong to overweight category and around 7% were obese. (Table.2)

Around 48% of the participants who do regular physical activity are diabetic while 64.2% of the participants who does not do regular physical activity are diabetic. Among the participants in overweight category 57% are diabetic and 73% of the participants in obese category were diabetic. (Table.2)

Discussion:

From our study we have found out that most of the diabetic cases are in the age group of 41-50(51%), this finding might be due to the fact that majority of the study population belongs to this age group (51.66%). Prevalence of type 2 DM was 46.2% and 56.9%, among subjects who are with normal BMI and overweight respectively. The Odds of developing type 2 Diabetes was 2.9 times among obese people compared to those with normal BMI.

Our findings are similar to other studies which also states that the risk of diabetes is higher among obese and overweight people compared to people normal BMI.^[13] Several studies reported independent predictor nature of BMI for development of diabetes^{[14,15,16,17,18]}

Another study done at U.S shows that the chance of developing diabetes in early ages is more for obese people compared to others, hence early identification of high BMI is necessary for the early diagnosis of Diabetes and thereby Primary prevention ^[18]. Our study shows that there is an association between physical activity and Diabetes. People not doing any physical activity are affected more by diabetes (64.2%). And the Odds of developing diabetes were 2.05 times more compared to those doing physical activities. Similar findings of significance of association of DM with physical activity were reported by some studies^[19].

All these results were obtained after adjusting for age and sex and found to be statistically significant. Our study result shows clearly that there is an association between BMI, physical activity and diabetes. Lack of exercise, a poor diet, were all associated with a significantly increased risk of diabetes. The majority of cases of type 2 diabetes could be prevented by the adoption of a healthier lifestyle. The public generally does not recognize the connection between overweight or obesity and diabetes. Weight control would be the most effective way to reduce the risk of type 2 diabetes. Hence proper Health education targeting all groups is essential. Similar type of community based studies should be done with large sample size.