Diabetes mellitus is a heterogeneous group of disorders, all characterized by increased plasma glucose. In the majority of patients with diabetes, the etiology of the disease is not understood. Expert panels have recommended one set of criteria for diagnosis and another set for classification . The criteria serve two purposes. One is to secure optimal treatment of the patient. The other is to support research aimed at understanding the aetiology and pathogenesis of diabetes syndromes Diabetes mellitus type 2 or type 2 diabetes (formerly called non-insulin-dependent diabetes mellitus (NIDDM), or adult-onset diabetes) is a disorder characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency.(Robbins et al ,2004)

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More than 220 million people worldwide have diabetes. In 2005, an estimated 1.1 million people died from diabetes.Almost 80% of diabetes deaths occur in low- and middle-income countries. Almost half of diabetes deaths occur in people under the age of 70 years; 55% of diabetes deaths are in women. WHO projects that diabetes death will double between 2005 and 2030.Healthy diet, regular physical activity, maintaining a normal body weight and avoiding tobacco use can prevent or delay the onset of diabetes.(WHO,2009)
Many types of diabetes are recognized (Tierney.L.M et al,2002) the principal three are:
Type 1: Failure to produce insulin by body mechanism resulting in diabetes. It is estimated that 5-10% of Americans who are diagnosed with diabetes have type 1 diabetes. Currently patients with type 1 diabetes take insulin injections.
Type 2: Results from insulin resistance, a condition in which cells fail to use insulin properly, may be combined with absolute insulin deficiency. Majority of patients world over who are diagnosed with diabetes have type 2 diabetes.
Gestational diabetes: Pregnant women who previously never had diabetes before but who have sudden increase in blood sugar (glucose) levels during pregnancy mainly due to change in their diet are said to have gestational diabetes. Gestational diabetes affects about 4% of all pregnant women. It may precede development of type 2 (or rarely type 1) Diabetes mellitus .
Type 1 Diabetes
Diabetes is a long-term (chronic) condition caused by the increase in level of glucose (sugar) in the blood. It is also known as diabetes mellitus.
In the UK, diabetes is seen in around 2.3 million people, and it’s estimated that there are more than half a million more people who have the condition but are not aware of it.
Normally a hormone called insulin regulates the blood sugar level, which is produced by the pancreas (a gland behind the stomach). When food is digested and enters the bloodstream, insulin moves any glucose out of the blood and into cells, where it is broken down to produce energy.
However, in those with diabetes, the body has higher level of glucose as it is stored and is unable to break down glucose into energy because there is either not enough insulin to breakdown glucose and store it as energy or because the insulin produced is not enough or does not work as required.
Gestational diabetes is caused by excess weight, obesity and Insulin Resistance are a condition that develops in the third trimester of pregnancy and affects 4-5 % of all pregnant women in the U.S. That is around 135,000 cases each year. With Gestational Diabetes, the insulin production by pancreas is normal but it doesn’t lower the mother’s blood sugar levels. The symptoms are only detectable by laboratory testing. Pregnant women can test their blood glucose level by urine dip stick test with each pre-natal visit. This test may show glucose in the urine, which is sign and will require health care provider to carry out further examinations for the presence of Gestational Diabetes, also known as Gestational Diabetes Mellitus http://weight.insulitelabs.com/Gestational-Diabetes.php
There are two types of diabetes – type 1 and type 2.
Type 1 diabetes occurs when the body produces no insulin. It is often referred to as insulin-dependent diabetes. It is also sometimes known as juvenile diabetes, or early-onset diabetes, because it usually develops before the age of 40, often in the teenage years.
Type 1 diabetes is far less common than type 2 diabetes, which occurs when there is too little insulin produced by the body to work, or when the cells in the body do not react properly to insulin. People with type 1 diabetes make up only 5-15% of all people with diabetes.
type 1 diabetes, will need insulin injections for life as well as blood glucose levels stay balanced by eating a healthy diet and carrying out regular blood tests http://www.nhs.uk/conditions/diabetes/Pages/Introduction.aspx
The main symptoms of diabetes are:
feeling very thirsty(polyphagia)
producing excessive amounts of urine(polyurea)
tiredness and lethargy
weight loss
muscle wasting (loss of muscle bulk).
Symptoms of type 1 diabetes can develop quickly, over weeks or even days. Other symptoms are: 
itchiness around the vagina or penis or getting thrush regularly,
blurred vision (caused by the lens of your eye becoming very dry), 
muscle cramps,
constipation
skin infections.
Hypoglycaemia (low blood glucose)
If a patient has diabetes, their blood glucose levels can become very low. This is known as hypoglycaemia (or a ‘hypo’), and happens because insulin produced by the body is more and has reduced the level of in the bloodstream.
In most cases, hypoglycaemia occurs if there is overdose of insulin, although it can also happen if you skip a meal, exercise very vigorously or drink alcohol on an empty stomach.
Symptoms of a ‘hypo’ include:
feeling shaky and irritable,
sweating
tingling lips
feeling weak
hunger
nausea
A hypoglycaemia can be brought under control simply by eating or drinking something with sugar in it . If a hypoglycaemia is not brought under control it can lead to confusion, slurred speech and unconsciousness. If this occurs there will be a need to have an emergency injection of a hormone called glucagon. This hormone will raise the level of glucose in your blood as it suppress the effect of insulin.
Hyperglycaemia (high blood glucose)
As diabetes occurs as a result of your body being unable to produce any, or enough, insulin to regulate your blood glucose level, your blood glucose levels may become very high. This happens because there is no insulin to breakdown glucose from the bloodstream and into the cells to produce energy.
Blood glucose levels become too high, it lead to  hyperglycaemia. The symptoms are similar to the main symptoms of diabetes, but they may come on suddenly and severely. They include:
extreme thirst
a dry mouth
blurred vision
drowsiness
a frequent need to pass urine.
If left untreated, hyperglycaemia can lead to complications such as diabetic ketoacidosis, which can eventually cause unconsciousness and even death. Diabetic ketoacidosis occurs when your body begins to break down fats for energy instead of glucose, leading to a build-up of acids in your blood urgent medical attention if diabetes develop in the body and this are the general signs and symptoms seen in case of diabetes
a loss of appetite,
nausea or vomiting (feeling or being sick),
a high temperature,
stomach pain or severe abdominal pain
a fruity smell on your breath, which may smell like pear drops or nail varnish.
http://www.nhs.uk/Conditions/Diabetes/Pages/Symptoms.aspx
The “McKeown thesis” and its Impact:
The McKeown thesis attempted to reason the phenomenal growth in population of the from late 18th century to the present day .McKeown’s thesis can be summarized as a steep growth in population was primarily due to decline in mortality form infectious diseases and the change in economic conditions due to industrial revolution ,which lead to improvement in rising of living standards and brought a gradual change in nutritional status that improved the human body’s resistance towards various diseases. The development in medical fields achieved by modern science did not make a significant contribution towards the population growth and was largely due to economic forces and changes in living and social conditions. This lead to McKeown reclassifying various fatal diseases recorded by General record office (GRO).McKeown classification was generally of three types
(1)Infectious diseases spread through air -Respiratory tuberculosis, Pneumonia, Bronchitis
(2) Infectious diseases spread through water or food – Cholera, Diarrhoea, Typhoid
(3) All other diseases contagious and degenerative
When a population develops it is important that the individuals are in a position to fight diseases and problems that can arise from them, this depends on the resources that they have. These resources could be knowledge, social setup, power, money. Those people who have access to resources have advantage and can gain health benefits from the public health system from those who are not in position to direct access to public health system. Resources are important in two different ways first , they can develop the individual’s behaviour towards health by helping them access and make choices and whether they could afford them all helping towards health enhancing behaviours and Second, resources are shaped across a broad range of contexts such as communities, neighbourhoods, social network , occupation and the risk as well as protecting factors .Housing for poor people would always be associated with pollution, noise, indifferent social conditions . Access to broad range of problems lie with socio economic condition of the individual like knowledge of best doctors and ideal treatment of medical problems and the freedom in making choices .The reason for social condition always being important is resources shape the access to health relevant circumstances . The social condition has been responsible for determining the quality of life and plays an important role as health determinant. (Link.B.G and Phelan.J.C 2003)
Mckeown was the former chairman of World health organization’s advisory group on health research strategy concludes that the average life expectancy had improved by 23 years in first half of century and medical therapy was responsible for only for few years of it. Meckeown believed that most this decrease was due to identification of bacilli which causes respiratory tuberculosis was not done till year 1882 and effective pharmacotherapy was not available till year 1947.
Between 1700 and 1915, the mortality rate in England declined from 27.9 deaths per thousand living to 14.4 and average life expectancy at birth Increased from 37.1 (in 1701) to 53.5 (in 1910-12). These figures reflect a major Improvement in the life-chances of the British population over the course of the Period, and therefore it is hardly surprising that the ‘McKeown thesis’, which attempts to account for the decline of mortality and the ‘modern rise of population’, has played a big role in economic, social and medical history as well as history of epidemiology and population studies In the years following the publication of McKeown thesis it is argued that it’s unlikely the dietary standards would have improved during the second half of 18th century as the value of wages was falling as there were apparent contradictions between real wages and mortality. (Wrigley and Schofield, 1981). McKeown argued that there was no means to fight air borne diseases in 18th century and the reduction in deaths was more likely due to improved human body resistance towards these diseases.
Illich was not content in criticizing modern medicines for to improve life expectancy , he proposed that medical interventions were in fact responsible for increasing the mortality rate by using ineffective and hazardous medical therapies which at times not tested or researched properly .Illich stated that chronic usages of drugs lead to numerous side-effects , infections acquired from hospitals , poorly performed surgeries as well as false positives and false negative tests from medical tests.
McKeown was aware that higher rate in fertility was responsible for increase in population rather than reduced mortality rate but dismissed it on grounds that higher birth rate means higher infant mortality as well due to the high risk parity of mothers so would not account for such a high rate of population growth. McKeown pointed out that mortality rates for most of the infectious diseases reduced considerably before any effective medical measure was in place. McKeown concluded that public health measure such as sewage disposal system, public waste disposal, and supply of clean and potable water and pasteurization of milk was important only from year1870, so the reason behind the decline mortality rate before this was according to McKeown due to improvement in living standards .Improvement in nutrition due to increase in agriculture productivity was also responsible for the increase in resistance to airborne infectious diseases such as Tuberculosis.(Grundy,2005). Preston’s article concluded that the increase in life expectancy all over the world between 1930s and 160s could not be totally attributed to increase in living standards and suggested that advances in medical care and public health did make significant contribution towards decline in mortality. Preston’s did make an effort to prove McKeown thesis wrong but had little influence on conventional belief and the theory of improved standard of living became conventional wisdom for that present time. (Mackenbach J P,2006)
It has recently been shown that McKeowns interpretations of his very own epidemiological data is flawed in many respects, firstly smallpox and diphtheria are two diseases that have been eradicated totally all over the world by vaccinations which is a preventive health measure .Positively the only three diseases to be eradicated before great world war was- cholera , typhoid and smallpox all these are attributed to public health measures and not nutrition .When all this data is analysed it goes to show that public health measures taken played the most decisive role in reduction of mortality . Furthermore since McKeowns work was published two significant forms of new evidence has appeared which slams the nutrition/living standard theory by McKeown. The first half of the century, the period which is under review suggests that as when the wages across sectors started improving, the reduction in mortality rate showed a slight decline from previous years and if wage increase meant better nutrition these was not seen in children .The growing cities and towns where the wage improvement were seen showed a trend of areas which had highest mortality rate and children were poorly developed (R.Woods and J.Woodward.1984).Although the points raised here are relevant they skew the main issue here which is that growth in income is not necessarily same all over the world and can vary considerably from developed countries to developing and underdeveloped countries .There are no patterns in cross-sectional associations between the income of a nation and progress in developing health standards as well as life expectancy of their population. Preston’s analysis underestimated the effects of economic development and its relation with reduction in mortality rate, that the relationship between the economic development and the developments in medical field are crude conceptualization between the two.
McKeown’s study can be explained by relevance of the question that underlines them. This concerns the importance of medical interventions, social, economic, political measures which affects the health status and health inequalities. Study suggest that measures need to be taken to improve health inequality and medical interventions and social changes has to be taken as complimenting rather than opposing each other .
Interventions
Type 1 diabetes is approached by primary, secondary, and tertiary intervention Primary intervention includes treatment of all individuals with diabetes. The possibility of using autoantigens new medium to combat diabetes as a vaccination is currently being explored not only in animal experiments but also in human tests. The selection of children on the basis of HLA type is being used to treat newborns with either oral or nasal insulin. Animal experiments have shown that treatment of spontaneously diabetic nonobese diabetic mice with GAD as a peptide, protein, or expressed in potatoes reduced diabetes. Vaccinations studies done both children and adults remain a future possibility to test determine whether type 1 diabetes can be prevented. (Lernmark.A.1999)
Secondary intervention involves screening for genetic, autoantibody, and other possible markers at birth, in school children, or in adults . Individuals classified with type 2 diabetes but positive for islet autoantibodies (representing slow-onset type 1 diabetes, latent autoimmune diabetes in the adult, or type 1.5 diabetes) are also being tested to determine whether they are suitable for immune intervention to preserve their ß-cell function. Recent studies in Japan suggested that early insulin treatment preserves ß-cell function. Several intervention trials are pending, including the use of subcutaneous or oral insulin in the Diabetes Prevention Trial for Type 1 Diabetes, milk formula or nasal insulin in Finland, aerosol insulin in Melbourne, or nicotinamide in the European Nicotinamide Diabetes Intervention Trial. In the next few years studies would find out the extent of such intervention trials preserve ß-cell function in subjects at risk for type 1 diabetes.(Lernmark.A.1999)
Tertiary intervention involves the treatment of patients diagnosed with type 1 diabetes very recently. Previous studies have demonstrated that treatment plans with satisfactory results are not present such as immunosuppression with cyclosporin and other agents has not been able to stop the pathogenetic process in new-onset patients. A future innovative treatment is planned so that it represents an antigen-specific immune intervention. Animal experiments have demonstrated that in case of early diagnosis or in patients with early onset the timely administration of antigen or insulin, at the time of clinical onset may slow the disease process.(Lernmark.A.1999)
Being active is referred to as physical activity (exercise) and is defined as the act of expending energy. It is generally categorized into two different types aerobic (requiring oxygen to maintain muscular effort) or anaerobic (not requiring oxygen to maintain muscular effort). The term exercise is used as a general label for being active and physical activity as well as exercise. Major challenges to decision making about exercise include how to develop and implement an efficient and effective exercise regimen, how to modify it to an individual patient’s motivation level knowing his mindset and barriers so that exercise will be initiated and maintained, and how to select, measure, and achieve specific, desired outcomes. Given these decision-making challenges Exercise interventions aimed at achieving these outcomes usually vary by type, intensity, duration and frequency. As with any type of self-care behaviors, barriers to exercise vary and are individual to particular patients depending on their health status as well as mindset. Among potential considerations for barriers has to be devised for individual patients type of exercise and duration, intensity, and frequency may need to be tailored to severity of progression of diabetes since complications such as neuropathy and retinopathy may affect the exercise capabilities of a diabetes patient. In addition, patients may consider availability of time, among many other factors such as age, job profile, social status and other medical complications, as posing a substantial barrier to integrating regular exercise or physical activity into normal daily lifestyle. Each of these poses challenges to the initiation and maintenance which is the more difficult part of exercise for patients and therefore to the measurement, monitoring, and management of exercise intervention outcomes for providers. Exercise is one of the most important features to both type 1 and type 2 diabetes patients. For type 2 diabetes patients, engaging in regular exercise may improve glycemic control and reduce the risk of vascular complications, increase insulin sensitivity, reduce stress and stave off depression and contribute to control of lipids and blood pressure, thereby reducing the risk of cardiovascular disease, the leading cause of death in diabetes patients.
Type 2 diabetes is determined primarily by lifestyle related factors and hereditary factors.
Lifestyle
A number of lifestyle factors are known to be important to the development of type 2 diabtetes. In one study, those who had high levels of physical activity, a healthy diet, did not smoke, and consumed alcohol in moderation had an 82% lower rate of diabetes. When a normal weight was included the rate was 89% lower. In this study a healthy diet was defined as one high in fiber, with a high polyunsaturated to saturated fat ratio, and a lower mean glycemic index. (Mozaffarian.D.et al 2009) Obesity has been found to contribute to approximately 55% type 2 diabetes, and decreasing consumption of saturated fats and trans fatty acids while replacing them with unsaturated fats may decrease the risk.(Saad.F.2009) increased rate of childhood obesity in between the 1960s and 2000s is beleived to have lead to the increase in type 2 diabetes in children and adolescents. (Rosenbloom.A. et al.2003)
Environmental toxins may contribute to recent increases in the rate of type 2 diabetes. A positive correlation has been found between the concentration in the urine of bisphenol A, a constituent of some plastics, and the incidence of type 2 diabetes. (Lang.A.2008)
Medical conditions
Subclinical Cushing’s syndrome (cortisol excess) may be associated with DM type 28The percentage of subclinical Cushing’s syndrome in the diabetic population is about 9%.Diabetic patients with a pituitary microadenoma can improve insulin sensitivity by removal of these microadenomas. (Taniguchi T.2008)
Hypogonadism is often associated with cortisol excess, and testosterone deficiency is also associated with diabetes mellitus type 2, even if the exact mechanism by which testosterone improve insulin resistance is still not known. (Farrell JB,2008)
Genetics
Both type 1 and type 2 diabetes are partly inherited. Type 1 diabetes may be triggered by certain infections, with some evidence pointing at Coxsackie B4 virus. There is a genetic element in individual susceptibility to some of these triggers which has been traced to particular HLA genotypes (i.e., the genetic “self” identifiers relied upon by the immune system). However, even in those who have inherited the susceptibility, type 1 diabetes mellitus seems to require an environmental trigger.
There is a stronger inheritance pattern for type 2 diabetes. Those with first-degree relatives with type 2 have a much higher risk of developing type 2, increasing with the number of those relatives. Gene expression promoted by a diet of fat and glucose as well as high levels of inflammation related cytokines found in the obese results in cells that “produce fewer and smaller mitochondria than is normal,” and are thus prone to insulin resistance.
COMPLICATIONS of Diabetes
Early complications-
Diabetic ketoacidosis is a medical emergency, because it can cause coma and death. Hospitalization, usually in an intensive care unit, is necessary. Large amounts of fluids are given intravenously along with electrolytes, such as sodium, potassium, chloride, and phosphate, to replace those fluids and electrolytes lost through excessive urination. Insulin is generally given intravenously so that it works quickly and the dose can be adjusted frequently. Blood levels of sugar, ketones, and electrolytes are measured every few hours. Doctors also measure the blood’s acid level. Sometimes, additional treatments are needed to correct a high acid level. However, controlling the levels of sugar in the blood and replacing electrolytes usually allow the body to restore the normal acid-base balance.( Robbins and Cotran,2007)
Late Complication of Diabetes Mellitus:
Macro-vascular complications as: Atherosclerosis with MI, CVA, peripheral vascular disease
Micro-vascular complications as: Diabetic Retinopathy Diabetic retinopathy refers to progressive pathologic alterations in the retinal microvasculature. In type 2 diabetes, though the incidence of blindness is lower, higher disease prevalence results in an even larger number of patients affected with severe visual loss.
Diabetic Neuropathy Diabetic neuropathy (DN) is a common and troublesome complication of diabetes mellitus, leading to great morbidity and mortality and resulting in a huge economic burden for care of the patient with diabetes mellitus. It is the most common form of neuropathy in the developed countries of the world, accounts for more hospitalizations than all the other diabetic complications combined, and is responsible for 50% to 75% of nontraumatic amputations and patients have serious co-morbid conditions, especially heart, eye, and peripheral vascular diseases.
Diabetic neuropathy is a heterogeneous disorder that encompasses a wide range of abnormalities affecting proximal and distal peripheral sensory and motor nerves as well as the autonomic nervous system. The major morbidity associated with somatic neuropathy is foot ulceration, the precursor of gangrene and limb loss. (Robbins and Cotran,2007)
Research on diabetes
The features of Type 1 diabetes in humans as well as mice in labororatory environment is significantly dependent on an relation between the environmental factors and genetic feature of humans as well as the study animal. Studies by Giulietti.A.et al(2004) al point towards vitamin D as being one of the environmental factors that can modulate the incidence of diabetes. This study further shows that in mice that developing Type 1 diabetes are generally at higher risk due to its genetics as well as vitamin D deficiency which leads to features seen in early part of life leading to a more aggressive form of the disease causing earlier onset, and a higher final incidence of the disease. This model of subtle vitamin D deficiency in early life, with only a marginal vitamin D deficiency in blood, but no effect on calcium concentration in serum or bone calcium content.
This is most probably the reflection of the vitamin D status in many infants and small children as this model has temporary and limited vitamin D deficiency, even in areas with high exposure to sunlight, since infants always are shielded from UV B exposure or direct exposure of sunlight. The application of vitamin D supplement is advised in many countries it is far from strictly controlled and many times, these supplements are omitted or administered irregularly or not paid enough importance to keep tab on their supply and demand. The higher incidence of Type 1 diabetes in the past two decades may be seen due the nutritional rickets which has never been completely eradicated in many countries and may be reappearing in may industrialize countries (Giulietti.A.et al, 2004).
It was found that the risks for diabetes in African-Americans, Hispanics, and Native Americans are approximately 2, 2.5, and 5 times greater, respectively, than in Caucasians being the least. Various national and ethnic populations within the U.S. to the total U.S. population were analyzed to find possible risk factors for the development of type 2 diabetes this was done by number of cross-sectional studies and prospective studies . Studies of the prevalence of type 2 diabetes in Mexican Americans and non-Hispanic whites in San Antonio showed that there is an inverse relationship between prevalence of diabetes generally and their current socioeconomic status. The cultural effects lead to an increased incidence of obesity in these populations which may also be related to their diet and physical activities, which may lead to insulin resistance. Genetic factors may also be a contributing factor. (Haffener.S.M 1998)
There are no high quality data on the research about the long lasting effectiveness of the dietary treatment of type 2 diabetes, however the data available indicate that the adoption of exercise which is a change in lifestyle appears to improve glycated haemoglobin at six and twelve months in people with type 2 diabetes. There is an urgent need for more well-designed studies which will analyse the wide range of interventions, at various points during follow-up (Moore.H. et al 2004)
Weight loss improves glycemic control with magnitude of improvement related to both magnitude of weight and characteristics of patient , the amount of weight loss required to reduce blood glucose is large, even modest weight loss produces glycemic control .The most important issue is how to improve weight loss especially long term weight loss, in type 2 diabetic patient .Dietary modification is most important direction in weight loss program (Hertzel.C.et al)
Implications for developing world
Type I diabetes is the only major organ-specific autoimmune disorder not to show a strong female bias. The overall sex ratio is roughly equal in children diagnosed under the age of 15 but while populations with the highest incidence all show male excess, the lowest risk populations studied, mostly of non-European origin, characteristically show a female bias. In contrast, male excess is a consistent finding in populations of European origin aged 15-40 years, with an approximate 3:2 male:female ratio. This ratio has remained constant in young adults over two or three generations in some populations. Further, fathers with Type I diabetes are more likely than affected mothers to transmit the condition to their offspring. Women of childbearing age are therefore less likely to develop Type I diabetes, and – should this occur – are less likely to transmit it to their offspring. Type II diabetes showed a pronounced female excess in the first half of the last century but is now equally prevalent among men and women in most populations, with some evidence of male preponderance in early middle age. Men seem more susceptible than women to the consequences of indolence and obesity, possibly due to differences in insulin sensitivity and regional fat deposition. Women are, however, more likely to transmit Type II diabetes to their offspring. Understanding these experiments of nature might suggest ways of influencing the early course of both forms of the disease.(Gale.E.A.M. et al 2001)
It is recognized that there will be substantially increased costs of widely applying the recommendations of study in the U.S on the Diabetes control and complications trial (DCCT). There will also need to be additional efforts to ensure professional education, so that health practitioners are implement this recommendations through the trial are able to effectively and safely implement the therapy employed in the DCCT. It is hoped that the benefits of trial are long term healthier; more productive lives with fewer complications will offset the costs of tight control. The cost-benefit ratio for intensive therapy in diabetes in this trial is in a range similar to other accepted treatments in the U.S that are