Prevalence Of Type 2 Diabetes.

Type 2 diabetes is the commonest type of diabetes accounting for 95% of cases and occurs mostly in middle age (1,2). It is the 4th or 5th leading cause of death in most developed countries (3). It is ( 4,5,6). Diabetes is becoming an increasing problem not only in the Western world but also in the developing world. It costs the UK’s National Health Service 13.7million a day to manage diabetes and its complications and it is predicted that the NHS funding for the disease will rise by 10% from its current 5% in 2011( 2, 7) . The complications of diabetes produce major health problems with 80% of diabetes- related mortality due to cardiovascular diseases (2). This essay will look at the prevalence of type 2 diabetes mellitus, the causes of the disease, why there is an increasing trend in type 2 diabetes case study India, the complications and the management of type 2 diabetes and a conclusion respectively.

Prevalence

There are presently 2million people in the UK diagnosed with diabetes of which 1.5million cases are type 2 diabetes and is estimated that over a million people have diabetes who have not been diagnosed yet (2,7). WHO predicts that the prevalence of diabetes will more than double from 150million in 2000 to 300million in 2025 and the increase will affect both industrialised countries and developing countries (1,8). But the impact of the increase is predicted to affect the developing countries more. For instance, India is expected to have a rise from 19million to 38million and China from 16million to 38million (1). Reports show the highest prevalence of 30-50% of adults among North American Indians and Pacific Islanders who have experienced a big change of diet from traditional healthy vegetable diets to fatty, high in carbohydrate western diet during the 20th century. (1). Graph1 shows the prevalence of type 2 diabetes in countries around the world from the World Health Organisation (WHO). Graph 1 that the highest prevalence is in India and this might be as a result of a change in from traditional lifestyle to sedentary lifestyles and genetic susceptibility.

Graph 1- The prevalence of type 2 diabetes in a range of countries around the word(9)

Adapted from WHO(9)

Causes of TYPE 2 DIABETES

Obesity

The UK has the fastest growing rate of obesity and increasing prevalence of type 2 diabetes is closely related to an increase prevalence of obesity (country doctor). The level of physical exercise is decreasing in individuals and most people now live a sedentary lifestyle and there is over-consumption of energy dense food leading to obesity (1,5). There is also an increasing prevalence of obesity among children and adolescent and putting them at risk of developing type 2 diabetes, 17% of children and adolescents aged 2-19 in the USA were overweight between 20003-2004 (10). Graph 2 shows a positive correlation between Body mass Index ( BMI) and age adjusted relative risk in women aged 30-55 in a study that took place in the USA. But a study in Northern Sweden from 1986 to 1999 showed a rise in the mean BMI from 25.3 to 26.6kg/cm2 and an increase in obesity from 11% to 15% resulted to no change in the prevalence of the diseas (1). A 40% or more increase in expected or recommended body weight leads to a 30-40% decline in insulin sensitivity to blood glucose levels (4). Longitudinal studies in different populations have shown that waist to hip ratio or waist circumference which measures reflects visceral and abdominal adiposity are more powerful determinants of risk of type 2 diabetes than BMI, while central adiposity determines insulin resistance (8). Women with a waist circumference greater than 31.5inches, white or black men with waist circumference greater than 37 inches and Asian men with waist circumference greater than 35inches have an increased risk of developing type 2 diabetes (2). 5-10cm reduction in waist circumference causes at least a 10% decrease in one of the risk factors of Coronary Heart disease (CHD) (4). Studies have shown that voluntary weight loss and vigorous exercise increases insulin sensitivity and slows the progression of impaired glucose tolerance (IGT) to type 2 diabetes (12) . Diets high in saturated fat causes an increased risk of the disease because of increased levels of free fatty acids resulting to insulin resistance, impaired pancreatic beta-cell function, change in TNF-alpha and adiponectin which modulate insulin resistance (11). It has been claimed that fish diets of the Eskimos and Japanese rich in Omega-3 polyunsaturated fat improve insulin sensitivity in skeletal muscles (1). More research needs to be done to confirm the association between omega-3 and insulin sensitivity and if successful people with insulin resistance could be encourage to eat food rich in omega-3 to improve insulin sensitivity rather than taking pharmaceutical products which have side effects. Finland has implemented a new prevention of programme which has proved that having a healthier diet and increasing the levels of physical exercise which maintains a good body weight reduces the risk of type 2 diabetes by 58% (2).

Overweight and obesity may not be an appropriate way of determining the susceptibility to type 2 diabetes in multi ethnic populations such as that in the UK and the USA due to variation in the body composition in individuals belonging to different ethnic groups and due to importance of distribution of excess adiposity. (8).

Graph 2- A graph showing the association between BMI and relative risk of developing type 2 diabetes

adapted from Diabetic medicine(11)

Ethnicity

Graph 3 shows that ethnicity is an independent determinant of the susceptibility to type 2 diabetes. South Asians and Afro-Caribbeans are five times more likely to suffer from the disease than Caucasians (2). Diabetes occurs after the ages of 40 and 25 in Caucasians and Afro-Carribeans respectively. But cases of early onset have seen among Caucasians due to the increasing prevalence of childhood type 2 diabetes, statistics from Diabetes UK shows that 0ver 1000 children who are all clinically obese have been diagnosed with the disease (2). South Asians tend to have a high triglyceride and low HDL-cholesterol levels and thus high prevalence of insulin resistance and Coronary heart disease (CHD) (1)

Graph 3- showing differences in prevalence