Etiology And Epidemiology Of Type 2 Diabetes Mellitus (T2DM)
Type 2 diabetes mellitus (T2DM) has been selected as the topic of this essay. First of all, a general description of diabetes mellitus is presented. The etiology and epidemiology of T2DM and its complications were specifically addressed. Subsequently, the major determinants of T2DM and analyses of 2 diabetic prevention programs were described.
Diabetes Mellitus
Diabetes Mellitus (DM) is one of the most common metabolic disorders all over the world. According to the International Diabetes Federation (IDF), 425 million adults aged 20-79 had diabetes mellitus globally in 2017. Diabetes mellitus is generally classified into two categories: (i) insulin dependent diabetes mellitus (IDDM) or Type 1 and non-insulin dependent diabetes mellitus (NIDDM) or Type 2. The Type 1 diabetes is often considered as an autoimmune disease and characterized by destruction of insulin secreting β-cells of the pancreas by the autoimmune reaction results hyperglycemia. On the other hand, the Type 2 diabetes, the cardinal topic of discussion for this essay, is characterized by abnormal insulin production and insulin insensitivity. Diabetes associated complication can generally be classified into two types i. e. acute and chronic complications. Acute complications are hypoglycemia, diabetic ketoacidosis (DHK), hyperglycemic diabetic coma, and loss of consciousness or seizures. Chronic complications are subdivided into two types are microvascular and macrovascular complications. Chronic microvascular complications include nephropathy, retinopathy, and neuropathy, whereas chronic macrovascular complications are the cardiovascular disease (CVD), diabetic foot, and diabetic encephalopathy. To understand the global trend of DM and its complications, epidemiological data must be presented.
IDF has estimated that approximately 629 million people will have DM worldwide by 2045 which is a 48% increase from 2017 (425 million). Among all form of diabetes, T2DM is the most common and accounts for nearly 90% of all diabetic cases. The actual causes of T2DM are still not fully understood, however, evidences indicate strong link with genetic predisposition, overweight and obesity, diet and sedentary lifestyle, and smokin. T2DM and its complications have tremendously influenced to the overall global burden of mortality and disability. A study in 2010 estimated that DM caused 3. 96 million deaths in the adult population aged 20-79 years. This estimate was increased to 4. 0 million deaths due to DM and its complications during 2017 in an IDF report, which is equivalent to one death every eight seconds. However, the number of death estimate is one million less than in 2015 likely owing to a worldwide reduction in all-cause mortality estimates. People with untreated and undiagnosed DM are at higher risk of complications than those who are diagnosed and receiving treatment. The IDF report estimates that half (212. 4 million) of the population (aged 20-79) worldwide have undiagnosed DM, and China, India, and the United States have the highest number of undiagnosed diabetes. Moreover, the health expenditure of patients with DM is about three times higher than for patients without DM.
On the other side, the IDF estimates that in 2017, USD 727 billion was spent on treating DM and its associated complications. China is listed as the country with the highest number of patients (114. 4 million) with diabetes mellitus (aged 20-79years) in 2017. A large-scale population based survey revealed that another 493. 4 million adults had prediabetes mellitus. According to WHO guideline, prediabetes is defined as 2-h oral glucose tolerance levels 7. 8-11. 0 mmol-1, and impaired fasting glucose, defined as fasting glucose levels 6. 1-6. 9 mmol-1. The IDF estimated that India had 72. 9 million people with DM securing the second position in 2017. They also estimate that number patients with DM will exceed China by 2045. A national study of India assumed that 77 million people had prediabetes mellitus in 2011. The USA was ranked with the third-highest number of people with DM in 2017, and 50% of adults aged 65 or older had prediabetes mellitus in 2008 . The total number of deaths due to DM and its complications in people aged 20-79 years was 285, 926 in North America and the Caribbean region. According to IDF 2017 report, about 66. 5% of these deaths occurred in high income countries; particularly in the USA, more than 176, 700 people were expected to die owing to DM, one highest number of deaths due to DM of any country in the world.
The Middle East is another major region of the global DM epidemic, with the prevalence of DM among adults 17. 7% in Saudi Arabia, 17. 3% in both Egypt and UAE. Despite a scarcity of updated regional data in Africa, IDF 2017 estimated a regional prevalence of 6% in 49 sub-Saharan countries and territories. According to the ranking of Global Burden of Disease Study, DM was listed as one of the leading causes of mortality and morbidity in Latin American Countries.
