Type 2 diabetes

From Wikipedia, the free encyclopedia

 

Type 2 diabetes
Other names	Diabetes mellitus type 2; adult-onset diabetes; noninsulin-dependent diabetes mellitus (NIDDM)
Universal blue circle symbol for diabetes
Pronunciation	/daɪəbiːtəs/
Specialty	Endocrinology
Symptoms	Increased thirst, frequent urination, unexplained weight loss, increased hunger
Complications	Hyperosmolar hyperglycemic state, diabetic ketoacidosis, heart disease, strokes, diabetic retinopathy, kidney failure, amputations
Usual onset	Middle or older age
Duration	Long term
Causes	Obesity, lack of exercise, genetics
Diagnostic method	Blood test
Prevention	Maintaining normal weight, exercising, eating properly
Treatment	Dietary changes, metformin, insulin, bariatric surgery
Prognosis	10 year shorter life expectancy
Frequency	392 million (2015)

Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, and unexplained weight loss. Symptoms may also include increased hunger, feeling tired, and sores that do not heal. Often symptoms come on slowly. Long-term complications from high blood sugar include heart disease, strokes, diabetic retinopathy which can result in blindness, kidney failure, and poor blood flow in the limbs which may lead to amputations. The sudden onset of hyperosmolar hyperglycemic state may occur; however, ketoacidosis is uncommon.

Type 2 diabetes primarily occurs as a result of obesity and lack of exercise. Some people are more genetically at risk than others. Type 2 diabetes makes up about 90% of cases of diabetes, with the other 10% due primarily to type 1 diabetes and gestational diabetes. In type 1 diabetes there is a lower total level of insulin to control blood glucose, due to an autoimmune induced loss of insulin-producing beta cells in the pancreas. Diagnosis of diabetes is by blood tests such as fasting plasma glucose, oral glucose tolerance test, or glycated hemoglobin (A1C).

Type 2 diabetes is largely preventable by staying a normal weight, exercising regularly, and eating properly. Treatment involves exercise and dietary changes. If blood sugar levels are not adequately lowered, the medication metformin is typically recommended. Many people may eventually also require insulin injections. In those on insulin, routinely checking blood sugar levels is advised; however, this may not be needed in those taking pills. Bariatric surgery often improves diabetes in those who are obese.

Rates of type 2 diabetes have increased markedly since 1960 in parallel with obesity. As of 2015 there were approximately 392 million people diagnosed with the disease compared to around 30 million in 1985. Typically it begins in middle or older age, although rates of type 2 diabetes are increasing in young people. Type 2 diabetes is associated with a ten-year-shorter life expectancy. Diabetes was one of the first diseases described. The importance of insulin in the disease was determined in the 1920s.

Signs and symptoms

Overview of the most significant symptoms of diabetes.

 

The classic symptoms of diabetes are polyuria (frequent urination), polydipsia (increased thirst), polyphagia (increased hunger), and weight loss. Other symptoms that are commonly present at diagnosis include a history of blurred vision, itchiness, peripheral neuropathy, recurrent vaginal infections, and fatigue. Many people, however, have no symptoms during the first few years and are diagnosed on routine testing. A small number of people with type 2 diabetes can develop a hyperosmolar hyperglycemic state (a condition of very high blood sugar associated with a decreased level of consciousness and low blood pressure).

Complications

Type 2 diabetes is typically a chronic disease associated with a ten-year-shorter life expectancy. This is partly due to a number of complications with which it is associated, including: two to four times the risk of cardiovascular disease, including ischemic heart disease and stroke; a 20-fold increase in lower limb amputations, and increased rates of hospitalizations. In the developed world, and increasingly elsewhere, type 2 diabetes is the largest cause of nontraumatic blindness and kidney failure. It has also been associated with an increased risk of cognitive dysfunction and dementia through disease processes such as Alzheimer's disease and vascular dementia. Other complications include acanthosis nigricans, sexual dysfunction, and frequent infections. There is also an association between type 2 diabetes and mild hearing loss.

Cause

The development of type 2 diabetes is caused by a combination of lifestyle and genetic factors. While some of these factors are under personal control, such as diet and obesity, other factors are not, such as increasing age, female gender, and genetics. Obesity is more common in women than men in many parts of Africa. A lack of sleep has been linked to type 2 diabetes. This is believed to act through its effect on metabolism. The nutritional status of a mother during fetal development may also play a role, with one proposed mechanism being that of DNA methylation. The intestinal bacteria Prevotella copri and Bacteroides vulgatus have been connected with type 2 diabetes.

Lifestyle

Lifestyle factors are important to the development of type 2 diabetes, including obesity and being overweight (defined by a body mass index of greater than 25), lack of physical activity, poor diet, stress, and urbanization. Excess body fat is associated with 30% of cases in those of Chinese and Japanese descent, 60–80% of cases in those of European and African descent, and 100% of cases in Pima Indians and Pacific Islanders. Among those who are not obese, a high waist–hip ratio is often present. Smoking appears to increase the risk of type 2 diabetes.

Dietary factors also influence the risk of developing type 2 diabetes. Consumption of sugar-sweetened drinks in excess is associated with an increased risk. The type of fats in the diet are important, with saturated fats and trans fatty acids increasing the risk, and polyunsaturated and monounsaturated fat decreasing the risk. Eating a lot of white rice appears to play a role in increasing risk. A lack of exercise is believed to cause 7% of cases. Persistent organic pollutants may play a role.

Genetics

Most cases of diabetes involve many genes, with each being a small contributor to an increased probability of becoming a type 2 diabetic. If one identical twin has diabetes, the chance of the other developing diabetes within his lifetime is greater than 90%, while the rate for nonidentical siblings is 25–50%. As of 2011, more than 36 genes had been found that contribute to the risk of type 2 diabetes. All of these genes together still only account for 10% of the total heritable component of the disease. The TCF7L2 allele, for example, increases the risk of developing diabetes by 1.5 times and is the greatest risk of the common genetic variants. Most of the genes linked to diabetes are involved in beta cell functions.

There are a number of rare cases of diabetes that arise due to an abnormality in a single gene (known as monogenic forms of diabetes or "other specific types of diabetes"). These include maturity onset diabetes of the young (MODY), Donohue syndrome, and Rabson–Mendenhall syndrome, among others. Maturity onset diabetes of the young constitute 1–5% of all cases of diabetes in young people.

Medical conditions

There are a number of medications and other health problems that can predispose to diabetes. Some of the medications include: glucocorticoids, thiazides, beta blockers, atypical antipsychotics, and statins. Those who have previously had gestational diabetes are at a higher risk of developing type 2 diabetes. Other health problems that are associated include: acromegaly, Cushing's syndrome, hyperthyroidism, pheochromocytoma, and certain cancers such as glucagonomas. Testosterone deficiency is also associated with type 2 diabetes.

Pathophysiology

Insulin resistance (right side) contributes to high glucose levels in the blood.

 

Type 2 diabetes is due to insufficient insulin production from beta cells in the setting of insulin resistance. Insulin resistance, which is the inability of cells to respond adequately to normal levels of insulin, occurs primarily within the muscles, liver, and fat tissue. In the liver, insulin normally suppresses glucose release. However, in the setting of insulin resistance, the liver inappropriately releases glucose into the blood. The proportion of insulin resistance versus beta cell dysfunction differs among individuals, with some having primarily insulin resistance and only a minor defect in insulin secretion and others with slight insulin resistance and primarily a lack of insulin secretion.

Other potentially important mechanisms associated with type 2 diabetes and insulin resistance include: increased breakdown of lipids within fat cells, resistance to and lack of incretin, high glucagon levels in the blood, increased retention of salt and water by the kidneys, and inappropriate regulation of metabolism by the central nervous system. However, not all people with insulin resistance develop diabetes, since an impairment of insulin secretion by pancreatic beta cells is also required.

Diagnosis

WHO diabetes diagnostic criteria

Condition	2-hour glucose	Fasting glucose	HbA1c
Unit	mmol/l(mg/dl)	mmol/l(mg/dl)	mmol/mol	DCCT %
Normal	<7 .8="" font="">	<6 .1="" font="">	<42 font="">	<6 .0="" font="">
Impaired fasting glycaemia	<7 .8="" font="">	≥6.1(≥110) & <7 .0="" font="">	42-46	6.0–6.4
Impaired glucose tolerance	≥7.8 (≥140)	<7 .0="" font="">	42-46	6.0–6.4
Diabetes mellitus	≥11.1 (≥200)	≥7.0 (≥126)	≥48	≥6.5

The World Health Organization definition of diabetes (both type 1 and type 2) is for a single raised glucose reading with symptoms, otherwise raised values on two occasions, of either:

• fasting plasma glucose ≥ 7.0 mmol/l (126 mg/dl)

or

• with a glucose tolerance test, two hours after the oral dose a plasma glucose ≥ 11.1 mmol/l (200 mg/dl)

A random blood sugar of greater than 11.1 mmol/l (200 mg/dl) in association with typical symptoms or a glycated hemoglobin (HbA_1c) of ≥ 48 mmol/mol (≥ 6.5 DCCT %) is another method of diagnosing diabetes. In 2009 an International Expert Committee that included representatives of the American Diabetes Association (ADA), the International Diabetes Federation (IDF), and the European Association for the Study of Diabetes (EASD) recommended that a threshold of ≥ 48 mmol/mol (≥ 6.5 DCCT %) should be used to diagnose diabetes. This recommendation was adopted by the American Diabetes Association in 2010. Positive tests should be repeated unless the person presents with typical symptoms and blood sugars >11.1 mmol/l (>200 mg/dl).

Threshold for diagnosis of diabetes is based on the relationship between results of glucose tolerance tests, fasting glucose or HbA_1c and complications such as retinal problems. A fasting or random blood sugar is preferred over the glucose tolerance test, as they are more convenient for people. HbA_1c has the advantages that fasting is not required and results are more stable but has the disadvantage that the test is more costly than measurement of blood glucose. It is estimated that 20% of people with diabetes in the United States do not realize that they have the disease.

Type 2 diabetes is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. This is in contrast to type 1 diabetes in which there is an absolute insulin deficiency due to destruction of islet cells in the pancreas and gestational diabetes that is a new onset of high blood sugars associated with pregnancy. Type 1 and type 2 diabetes can typically be distinguished based on the presenting circumstances. If the diagnosis is in doubt antibody testing may be useful to confirm type 1 diabetes and C-peptide levels may be useful to confirm type 2 diabetes, with C-peptide levels normal or high in type 2 diabetes, but low in type 1 diabetes.

Screening

No major organization recommends universal screening for diabetes as there is no evidence that such a program improve outcomes. Screening is recommended by the United States Preventive Services Task Force (USPSTF) in adults without symptoms whose blood pressure is greater than 135/80 mmHg. For those whose blood pressure is less, the evidence is insufficient to recommend for or against screening. There is no evidence that it changes the risk of death in this group of people. They also recommend screening among those who are overweight and between the ages of 40 and 70.

The World Health Organization recommends testing those groups at high risk and in 2014 the USPSTF is considering a similar recommendation. High-risk groups in the United States include: those over 45 years old; those with a first degree relative with diabetes; some ethnic groups, including Hispanics, African-Americans, and Native-Americans; a history of gestational diabetes; polycystic ovary syndrome; excess weight; and conditions associated with metabolic syndrome. The American Diabetes Association recommends screening those who have a BMI over 25 (in people of Asian descent screening is recommended for a BMI over 23).

Prevention

Onset of type 2 diabetes can be delayed or prevented through proper nutrition and regular exercise. Intensive lifestyle measures may reduce the risk by over half. The benefit of exercise occurs regardless of the person's initial weight or subsequent weight loss. High levels of physical activity reduce the risk of diabetes by about 28%. Evidence for the benefit of dietary changes alone, however, is limited, with some evidence for a diet high in green leafy vegetables and some for limiting the intake of sugary drinks. There is an association between higher intake of sugar-sweetened fruit juice and diabetes, but no evidence of an association with 100% fruit juice. A 2019 review found evidence of benefit from dietary fiber.

In those with impaired glucose tolerance, diet and exercise either alone or in combination with metformin or acarbose may decrease the risk of developing diabetes. Lifestyle interventions are more effective than metformin. A 2017 review found that, long term, lifestyle changes decreased the risk by 28%, while medication does not reduce risk after withdrawal. While low vitamin D levels are associated with an increased risk of diabetes, correcting the levels by supplementing vitamin D3 does not improve that risk.

Management

Management of type 2 diabetes focuses on lifestyle interventions, lowering other cardiovascular risk factors, and maintaining blood glucose levels in the normal range. Self-monitoring of blood glucose for people with newly diagnosed type 2 diabetes may be used in combination with education, although the benefit of self-monitoring in those not using multi-dose insulin is questionable. In those who do not want to measure blood levels, measuring urine levels may be done. Managing other cardiovascular risk factors, such as hypertension, high cholesterol, and microalbuminuria, improves a person's life expectancy. Decreasing the systolic blood pressure to less than 140 mmHg is associated with a lower risk of death and better outcomes. Intensive blood pressure management (less than 130/80 mmHg) as opposed to standard blood pressure management (less than 140-160 mmHg systolic to 85–100 mmHg diastolic) results in a slight decrease in stroke risk but no effect on overall risk of death.

Intensive blood sugar lowering (HbA_1c<6 as="" ba="" blood="" lowering="" opposed="" standard="" sub="" sugar="" to="">1c

of 7–7.9%) does not appear to change mortality. The goal of treatment is typically an HbA_1c of 7 to 8% or a fasting glucose of less than 7.2 mmol/L (130 mg/dl); however these goals may be changed after professional clinical consultation, taking into account particular risks of hypoglycemia and life expectancy. Despite guidelines recommending that intensive blood sugar control be based on balancing immediate harms with long-term benefits, many people – for example people with a life expectancy of less than nine years who will not benefit, are over-treated.

It is recommended that all people with type 2 diabetes get regular eye examinations. There is weak evidence suggesting that treating gum disease by scaling and root planing may result in a small short-term improvement in blood sugar levels for people with diabetes. There is no evidence to suggest that this improvement in blood sugar levels is maintained longer than 4 months. There is also not enough evidence to determine if medications to treat gum disease are effective at lowering blood sugar levels.

Lifestyle

A proper diet and exercise are the foundations of diabetic care, with a greater amount of exercise yielding better results. Exercise improves blood sugar control, decreases body fat content and decreases blood lipid levels, and these effects are evident even without weight loss. Aerobic exercise leads to a decrease in HbA_1c and improved insulin sensitivity. Resistance training is also useful and the combination of both types of exercise may be most effective.

A diabetic diet that promotes weight loss is important. While the best diet type to achieve this is controversial, a low glycemic index diet or low carbohydrate diet has been found to improve blood sugar control. A very low calorie diet, begun shortly after the onset of type 2 diabetes, can result in remission of the condition. Viscous fiber supplements may be useful in those with diabetes.

Vegetarian diets in general have been related to lower diabetes risk, but do not offer advantages compared with diets which allow moderate amounts of animal products. There is not enough evidence to suggest that cinnamon improves blood sugar levels in people with type 2 diabetes.

Culturally appropriate education may help people with type 2 diabetes control their blood sugar levels, for up to 24 months. If changes in lifestyle in those with mild diabetes has not resulted in improved blood sugars within six weeks, medications should then be considered. There is not enough evidence to determine if lifestyle interventions affect mortality in those who already have DM2.

Medications

Metformin 500mg tablets.

 

There are several classes of anti-diabetic medications available. Metformin is generally recommended as a first line treatment as there is some evidence that it decreases mortality; however, this conclusion is questioned. Metformin should not be used in those with severe kidney or liver problems.

A second oral agent of another class or insulin may be added if metformin is not sufficient after three months. Other classes of medications include: sulfonylureas, thiazolidinediones, dipeptidyl peptidase-4 inhibitors, SGLT2 inhibitors, and glucagon-like peptide-1 analogs. As of 2015 there was no significant difference between these agents. A 2018 review found that SGLT2 inhibitors may be better than glucagon-like peptide-1 analogs or dipeptidyl peptidase-4 inhibitors.

Rosiglitazone, a thiazolidinedione, has not been found to improve long-term outcomes even though it improves blood sugar levels. Additionally it is associated with increased rates of heart disease and death. Angiotensin-converting enzyme inhibitors (ACEIs) prevent kidney disease and improve outcomes in those with diabetes. The similar medications angiotensin receptor blockers (ARBs) do not. A 2016 review recommended treating to a systolic blood pressure of 140 to 150 mmHg.

Injections of insulin may either be added to oral medication or used alone. Most people do not initially need insulin. When it is used, a long-acting formulation is typically added at night, with oral medications being continued. Doses are then increased to effect (blood sugar levels being well controlled). When nightly insulin is insufficient, twice daily insulin may achieve better control. The long acting insulins glargine and detemir are equally safe and effective, and do not appear much better than neutral protamine Hagedorn (NPH) insulin, but as they are significantly more expensive, they are not cost effective as of 2010. In those who are pregnant, insulin is generally the treatment of choice.

Vitamin D supplementation to people with type 2 diabetes may improve markers of insulin resistance and HbA1c.

Surgery

Weight loss surgery in those who are obese is an effective measure to treat diabetes. Many are able to maintain normal blood sugar levels with little or no medication following surgery and long-term mortality is decreased. There however is some short-term mortality risk of less than 1% from the surgery. The body mass index cutoffs for when surgery is appropriate are not yet clear. It is recommended that this option be considered in those who are unable to get both their weight and blood sugar under control.

Epidemiology

Regional rates of diabetes using data from 195 countries in 2014

 

Globally as of 2015 it was estimated that there were 392 million people with type 2 diabetes making up about 90% of diabetes cases. This is equivalent to about 6% of the world's population. Diabetes is common both in the developed and the developing world. It remains uncommon, however, in the least developed countries.

Women seem to be at a greater risk as do certain ethnic groups, such as South Asians, Pacific Islanders, Latinos, and Native Americans. This may be due to enhanced sensitivity to a Western lifestyle in certain ethnic groups. Traditionally considered a disease of adults, type 2 diabetes is increasingly diagnosed in children in parallel with rising obesity rates. Type 2 diabetes is now diagnosed as frequently as type 1 diabetes in teenagers in the United States.

Rates of diabetes in 1985 were estimated at 30 million, increasing to 135 million in 1995 and 217 million in 2005. This increase is believed to be primarily due to the global population aging, a decrease in exercise, and increasing rates of obesity. The five countries with the greatest number of people with diabetes as of 2000 are India having 31.7 million, China 20.8 million, the United States 17.7 million, Indonesia 8.4 million, and Japan 6.8 million. It is recognized as a global epidemic by the World Health Organization.

History

Diabetes is one of the first diseases described with an Egyptian manuscript from c. 1500 BCE mentioning "too great emptying of the urine." The first described cases are believed to be of type 1 diabetes. Indian physicians around the same time identified the disease and classified it as madhumeha or honey urine noting that the urine would attract ants. The term "diabetes" or "to pass through" was first used in 230 BCE by the Greek Apollonius Of Memphis. The disease was rare during the time of the Roman empire with Galen commenting that he had only seen two cases during his career.

Type 1 and type 2 diabetes were identified as separate conditions for the first time by the Indian physicians Sushruta and Charaka in 400–500 AD with type 1 associated with youth and type 2 with being overweight. The term "mellitus" or "from honey" was added by the Briton John Rolle in the late 1700s to separate the condition from diabetes insipidus which is also associated with frequent urination. Effective treatment was not developed until the early part of the 20th century when the Canadians Frederick Banting and Charles Best discovered insulin in 1921 and 1922. This was followed by the development of the long acting NPH insulin in the 1940s.

Epidemiology of metabolic syndrome

From Wikipedia, the free encyclopedia

 

This article provides a global overview of the current trends and distribution of metabolic syndrome. Metabolic syndrome (also known as the cardiometabolic syndrome) refers to a cluster of related risk factors for cardiovascular disease that includes abdominal obesity, diabetes, hypertension, and elevated cholesterol.

 

Data from the World Health Organization suggests 65% of the world's population live in countries where being overweight or obese kills more people than being underweight. The WHO defines “overweight” as a BMI greater than or equal to 25, and “obesity” as a BMI greater than or equal to 30. Both overweight and obesity are major risk factors for cardiovascular diseases, specifically heart disease and stroke, and diabetes.

The International Diabetes Federation reports that as of 2011, 366 million people suffer from diabetes; this number is projected to increase to over half a billion (estimated 552 million) by 2030. 80 percent of people with diabetes live in developing countries and in 2011, diabetes caused 4.6 million deaths and approximately 78,000 children were diagnosed with type 1 diabetes.

Background

Different definitions of the cardiometabolic syndrome have been proposed by different public health organizations, but recently the International Diabetes Federation (IDF), the National Heart, Lung, and Blood Institute (NHLBI), the American Heart Association (AHA), and others proposed a definition for diagnosing the cardiometabolic syndrome that includes the presence of 3 out of the following 5 risk factors:

• Fasting plasma glucose greater than or equal to 100 mg/dL, or undergoing drug treatment for elevated glucose
• HDL cholesterol less than 40 mg/dL in men or less than 50 mg/dL in women, or undergoing drug treatment for reduced HDL cholesterol
• Triglycerides greater than or equal to 150 mg/dL, or undergoing drug treatment for elevated triglycerides
• Waist circumference greater than or equal to 102 cm in men or 88 cm in women (in the United States)
• Blood pressure greater than or equal to 130 mm Hg systolic or 85 mm Hg diastolic, or undergoing drug treatment for hypertension

Approximately 20 – 25 percent of the world’s adult population has the cluster of risk factors that is metabolic syndrome. In 2000, approximately 32% of U.S. adults had the metabolic syndrome. In more recent years that figure has climbed to 34%.

People with the cardiometabolic syndrome have twice the likelihood of developing and dying from cardiovascular disease, and more than seven times the risk of developing diabetes, compared to those with no cardiometabolic risk factors.

Africa

Diabetes now affects over 14 million people in the central and southern regions of Africa; this number is expected to increase to 28 million people by 2030, according to the IDF Africa. The NGO Project Hope cites lifestyle changes as the primary cause of the increase of diabetes, specifically type 2 diabetes, which seems to correspond with a growing waist line. Lack of physical activity, increased consumption of processed food and unmanaged portion sizes all contribute to the rise of diabetes – a major component of cardiometabolic risk. In countries where there are food crises, “much of the foods donated from the international community are calorie-dense foods”, according to Project Hope’s Senior Advisor, Paul Madden. Nutrition education is essential to prevent type 2 diabetes from consuming the continent. The NGO also suggests that in some villages, 70 to 80 percent of the people may not even be aware that they are living with the disease.

Studies published in the Indian Journal of Endocrinology and Metabolism focused on the prevalence of metabolic syndrome and its components in different African populations using various criteria. Reports from Lagos, Nigeria, for instance, showed the prevalence rate of metabolic syndrome as high as over 80% among diabetic patients. The current trend of rising metabolic syndrome in African populations is largely and generally attributed to “adoption of western lifestyle which is characterized by reduced physical activity, substitution of the traditional African diet rich in fruits, and vegetables for the more energy-laden foods”.

Europe

Currently, more than 55 million people in Europe have been diagnosed with diabetes, according to the IDF; by 2030 this total will rise to 64 million people. Roughly 8.4% of adults are suffering from the effects of this disease, which caused 622,114 deaths in the region this year.33 IDF studies have also concluded that Europe has the highest number of children with type 1 diabetes.

The European Global Cardiometabolic Risk Profile in Patients with Hypertension Disease (GOOD) survey investigated the cardiometabolic risk profile in adult patients with hypertension across 289 locations in four European regions. Across the Northwest, Mediterranean, Atlantic European Mainland and Central Europe zones, demographic, lifestyle, clinical and laboratory data were collected from eligible patients during one clinic visit. In Central Europe 44% of the participants had type 2 diabetes compared with 33% in the Atlantic European Mainland, and 26% in the Northwest and the Mediterranean regions. The study revealed a prevalence of metabolic syndrome affected 68% of Central Europe, 60% of the Atlantic European Mainland, 52% of the Mediterranean regions and 50% of Northwest Europe. Fasting blood glucose, total cholesterol and triglyceride levels were all highest in Central Europe compared with the other three regions. Roughly 80% of the Atlantic European Mainland patients had uncontrolled blood pressure, whereas the other three regions tallied approximately 70-71%. Compared to the Northwest, Mediterranean, and Central Europe regions, declared alcohol consumption was also recorded the highest in the Atlantic European Mainland; exercise was lowest in Central Europe.

The GOOD survey recorded cases of congestive heart failure, left ventricular hypertrophy, coronary artery disease and stable/unstable angina were highest in Central Europe compared with the other regions. Family history of premature stroke or myocardial infarction, stroke, coronary revascularization and transient ischaemic attacks had the highest prevalence in the Atlantic European Mainland. Statistical conclusions indicate that hypertensive patients across Europe exhibit multiple cardiometabolic risk factors, with greater predominance in Central Europe and the Atlantic European Mainland compared with Northwest and Mediterranean regions.

Middle East and North Africa

The International Diabetes Federation reports more than 34.2 million people in the Middle East and North Africa have diabetes; this number will rise to 59.7 million by the year 2030 unless counteractive measures are introduced. In 2012, diabetes caused 356,586 deaths in this region, a zone with the highest prevalence of diabetes in adults (11%) in the world.

Turkey reported a prevalence of 33.9% for metabolic syndrome (MS), with a higher prevalence in women (39.6%) than in men (28%). The survey included random samples from both urban and rural populations in seven geographical regions of Turkey. More than one-third (35.08%) of the participants were obese. Of those tested, 13.66% had hypertension, while those with diabetes mellitus (DM) and MS were 4.16% and 17.91%, respectively. The frequency of hypertension, MS and obesity were higher in females than males; however, DM was higher in males than females. According to the IDF, metabolic syndrome was prevalent in 16.1% of the Saudi Arabian population. In Tunisia, metabolic syndrome incidence was 45.5% based on the IDF criteria. 37.4% of Iranians aging from 25-64, living in both urban and rural areas of all 30 provinces in Iran, had MS (based on the IDF definition); results based on the Adult Treatment Panel III (ATPIII)/American Heart Association (AHA)/National Heart, Lung, and Blood Institute (NHLBI) standards suggest 41.6% of the same group of Iranians suffer from metabolic syndrome. The affliction of the MS is estimated to affect more than 11 million Iranians.

North America and the Caribbean

Current IDF data proposes more than 38.4 million people in North American and the Caribbean have diabetes and projects this number will increase to 51.2 million by 2030. In 2012, 11% of (or approximately 4.2 million) adults in the NAC Region endured the disease; this year, diabetes was responsible for 287,020 deaths in North America.

The National Center for Biotechnological Information notes the incidence of the metabolic syndrome among Caribbean-born persons in the U. S. Virgin Islands is comparable to that among the population on the mainland of the United States. The groups involved in the study were Hispanic white, Hispanic black, non-Hispanic black born in the U.S. Virgin Islands, and non-Hispanic black born elsewhere in the Caribbean. Hispanic ethnicity was independently associated with an increased risk of having the metabolic syndrome, high triglycerides, and low high density lipoprotein cholesterol levels. Among Caribbean-born persons living in the U.S. Virgin Islands, those who are Hispanic blacks may have a greater risk of cardiovascular disease than do other groups.

United States

Approximately 27 million Americans, or nearly 11% of the population, have diabetes, according to the American Diabetes Association and the Centers for Disease Control and Prevention. By 2050, the prevalence of diabetes could increase to as much as 33% of the population, largely due to the aging of the population and to people with diabetes living longer. Approximately 1.9 million new cases of diabetes are diagnosed each year. The disease was the seventh leading cause of death in 2007, directly claiming more than 71,000 lives and contributing to approximately 160,000 additional deaths. Patients with diabetes are two to four times more likely than those without it to die from cardiovascular disease, and diabetes is an important cause of blindness, kidney disease, and lower-extremity amputations.

An additional 79 million Americans have prediabetes. Individuals with prediabetes have blood glucose levels that are higher than normal but not high enough to be classified as diabetes. Without intervention, most people with prediabetes will develop diabetes within ten years. In addition, studies have shown that these individuals are at increased risk for cardiovascular disease, including a heart attack or stroke. Individuals with prediabetes are also likely to have additional cardiovascular risk factors such as elevated cholesterol and high blood pressure.

Diabetes and prediabetes are strongly linked to obesity and overweight. Nearly 50% of people with diabetes are obese, and 90% are overweight. 19 A chief risk factor for prediabetes is excess abdominal fat. Obesity increases one’s risk for a variety of other medical problems, including hypertension, stroke, other forms of cardiovascular disease, arthritis, and several forms of cancer. Obese individuals are at twice the risk of dying from any cause than normal-weight individuals. The prevalence of obesity and overweight have risen to epidemic proportions in the United States, where 67% of adults are overweight and, of these, approximately half are obese.

The prevalence of hypertension, another cardiometabolic syndrome component, has been increasing for the last decade. In 1994, 24% of U.S. adults had hypertension. Today, that figure has risen to 29%, according to data from the National Health and Nutrition Examination Survey. In addition, nearly 30% of U.S. adults have prehypertension. Hypertension increases one’s risk of suffering a stroke, developing end-stage renal disease, and dying from cardiovascular disease. In recent years, hypertension has directly claimed more than 61,000 U.S. lives and has contributed to approximately 347,000 deaths each year.

Of the components of the cardiometabolic syndrome, only the prevalence of dyslipidemia has declined in the United States. Between 1999 and 2010, the percentage of U.S. adults with high total cholesterol declined from approximately 18% to 13%. However, according to the American Heart Association, nearly half of U.S. adults today (44%) are still at increased risk for atherosclerotic disease because their levels of total cholesterol are elevated (200 mg/dL or higher). Of these 98.8 million individuals with elevated cholesterol, 33.6 million have high cholesterol (240 mg/dL or above), and 71.3 million have low-density lipoprotein (LDL) cholesterol levels of 130 mg/dL or higher. In addition, approximately 19% of U.S. adults have low levels of high-density lipoprotein (HDL) cholesterol, and one-third have elevated triglycerides. Finally, dyslipidemia affects the vast majority (up to 97%) of individuals with diabetes and contributes to their elevated risk for cardiovascular disease.

United states children

According to estimates from the American Heart Association, more than 9% of U.S. children and adolescents aged 12–19, or nearly three million individuals, have the metabolic syndrome.^[31] Among overweight and obese adolescents, this prevalence rate rises to 44%. Two-thirds of adolescents have at least one metabolic abnormality.

Preliminary prospective studies report that children and adolescents with the metabolic syndrome are at high risk of developing cardiovascular disease and diabetes as adults. One 25-year prospective study found that, compared with children without the syndrome, those with the metabolic syndrome are 14 times more likely to suffer from cardiovascular disease and 11 times more likely to develop diabetes when they reach adulthood. Cardiometabolic risk among children and adolescents is fueled by the rising prevalence of obesity in this age group. From 1980 to 2008, rates of obesity have increased from 5% to 10% among preschool children aged 2–5. During the same time period, obesity increased from 6.5% to nearly 20% among 6-11year-olds and from 5% to 18% among adolescents aged 12–19. Hypertension among children and adolescents has increased by 1% since 1999 and is estimated to affect 3.6% of those aged 3–18. This increase is attributed to the rising number of overweight and obese children. The prevalence of lipid abnormalities among children and adolescents is also tied to obesity and overweight. Approximately 14% of normal-weight youths aged 12–19 have lipid abnormalities. That figure rises to 22% of overweight youths and nearly 43% of obese youths.

Obesity is also tied to the rise of type 2 diabetes among U.S. children. Until recently, diabetes in children was typically assumed to be type 1, formerly known as juvenile-onset diabetes. However, according to the Centers for Disease Control and Prevention, recent clinical evidence indicates that the prevalence of type 2 diabetes, formerly known as adult-onset diabetes, is increasing among American children and adolescents. This increase is most notable among Blacks, Asian/Pacific Islanders, Hispanics, and American Indians. Children who develop type 2 diabetes are typically overweight or obese. “Type 2 diabetes in children and adolescents already appears to be a sizable and growing problem,” the CDC says. “Better physician awareness and monitoring of the disease’s magnitude will be necessary.”

Native Americans (American Indians)

The National Cholesterol Education Program compiled and presented data from the Indian Health Service that indicates increasing mortality rates due to cardiovascular disease vary among American Indian communities. The significant independent predictors of CVD in Native American women were diabetes, age, obesity, LDL, albuminuria, triglycerides, and hypertension. In men the significant predictors of CVD were diabetes, age, LDL, albuminuria, and hypertension. Unlike other ethnic groups, Native Americans appear to have an increasing frequency of coronary heart disease, possibly related to the high and increasing prevalence of diabetes in these communities. Although total and LDL-cholesterol levels are lower than the U.S. average, importance of LDL cholesterol as a contributor to CHD in this group should not be underestimated. Moreover, because of the high frequency of type 2 diabetes, many Native Americans will have an even lower LDL goal. The evidence for differences in baseline risk between Native American and white populations is not strong enough to justify separate guidelines for Native American populations.

South and Central America

The IDF reports 9.2% of adults in the South and Central America have diabetes and 12.3% of deaths in adults in the SACA Region can be attributed to the disease. More than 26.4 million people in the SACA Region have diabetes; by 2030 this will rise to 39.9 million. Approximately 236,328 disease related fatalities occurred in the SACA Region in 2012.

The Latin American populations exhibit a high prevalence of abdominal obesity and metabolic syndrome, similar or even higher than developed countries. It is attributed to changes in their lifestyle, migration from rural to urban areas and a higher susceptibility to accumulate abdominal fat and develop more insulin resistance compared to other ethnically different populations. Some genetic factors and metabolic adaptations during fetal life can be claimed as etiological factors of this condition.

Although cardiovascular disease (CVD) is the leading cause of death and disability in the majority of the countries in Latin America, few data about regional differences on this topic has emerged. Developing countries have scarce epidemiological data on cardiovascular (CV) risk factor prevalence, which only allows for limited control and treatment options. The load of the CV risk factors, especially hypertension, remains uncertain.

South-East Asia

A 2012 IDF South-East Asia report states one fifth of all adults living with diabetes live in South East Asia and 8.7% of adults in the region endure the disease, according to the International Diabetes Federation. As of this 2012, 70.3 million people in the SEA Region have diabetes; by 2030 this will rise to 120.9 million diagnoses.

There has been special interest in South Asians because they have been reported to have very high frequency rates of coronary heart disease at younger ages in the absence of traditional risk factors. The higher CHD risk in this population may be related in part to a higher prevalence of insulin resistance, the metabolic syndrome, and diabetes. Lipoprotein levels have also been reported to be elevated, elevating the importance of initiating remedies to reduce cholesterol and other CHD risk factors in this group with South Asian Indian ancestry. A growing body of evidence indicates that South Asians are at high baseline risk for CHD, compared to American whites; they are particularly at risk for the metabolic syndrome and type 2 diabetes. Also, increased emphasis should be given to life habit changes to mitigate the metabolic syndrome in this population. All other data reflects cholesterol management guidelines should remain the same for the SEA population as well as for other population groups.

Western Pacific

The IDF Western pacific reports more people with diabetes live in the Western Pacific than any other region in the world. Approximately 132.2 million people in the WP Region have diabetes; if proper precautions are not utilized, this number is projected to escalate to 187.9 million people by 2030. 44 8% of all Western Pacific adults have diabetes and in 2012, the illness caused 1.7 million deaths in the Western Pacific.

There is limited information on the risks and benefits of lipid management for reduction of coronary heart disease (CHD) and cardiovascular disease (CVD) in this population. In the Honolulu Heart Program report, CHD and CVD mortality rates are lower than in the general U.S. population. However, the evidence for differences between Pacific Islander and general U.S. Populations is not strong enough to justify the creating of separate guidelines.

Epidemiology of obesity

From Wikipedia, the free encyclopedia

 

World obesity prevalence among males.

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World obesity prevalence among females.

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Obesity has been observed throughout human history. Many early depictions of the human form in art and sculpture appear obese. However, it was not until the 20th century that obesity became common — so much so that, in 1997, the World Health Organization (WHO) formally recognized obesity as a global epidemic. Obesity is defined as having a body mass index (BMI) greater than or equal to 30 kg/m², and in June 2013 the American Medical Association classified it as a disease, with much controversy.

In countries of the Organisation for Economic Co-operation and Development (OECD), one child out of five is overweight or obese. Once considered a problem only of high-income countries, obesity rates are rising worldwide. Globally, there are now more people who are obese than who are underweight, a trend observed in every region over the world except parts of sub-Saharan Africa and Asia. In 2013, an estimated 2.1 billion adults were overweight, as compared with 857 million in 1980. Of adults who are overweight, 31% are obese. Increases in obesity have been seen most in urban settings.

Since body fat can be measured in several ways, statistics on the epidemiology of obesity vary between sources. While BMI is the most basic and commonly used indicator of obesity, other measures include waist circumference, waist-to-hip ratio, skinfold thicknesses, and bioelectrical impedance. The rate of obesity increases with age at least up to 50 or 60 years old.

Africa

Obesity rates in Western Africa are estimated to be 10%. Rates of obesity among women are three times those found in men. In urban West Africa rates of obesity have more than doubled in the last 15 years.

Egypt

In Egypt, according to data from the 2016 Global Burden of Disease study, overweight and obesity (as measured by high BMI) was the country's leading risk factor driving the most death and disability combined.

Asia

China

China is currently facing challenges of overnutrition. This is believed to be primarily due to the rapid declines in physical activity and changing dietary habits which have occurred between the 1980s and the 2000s. The decline in physical activity is attributed to increasing technology in the workplace and changing leisure activities.

In 1989 65% of Chinese had jobs that required heavy labor. This decreased to 51% in the year 2000. Combined with this has been a change to a diet higher in meat and oil, and an increase in overall available calories. Available calories per person increased from 2,330 kilocalories (9,700 kJ) per day in 1980 to 2,940 kilocalories (12,300 kJ) per day in 2002. Rates of overweight and obese adults increased 12.9% in 1991 to 27.3% in 2004.

Overall rates of obesity are below 5% in China as a whole but are greater than 20% in some cities.

India

Obesity has reached epidemic proportions in India in the 21st century, with morbid obesity affecting 5% of the country's population. Obesity is a major risk factor for cardiovascular disease and NGOs such as the Indian Heart Association have been raising awareness about this issue. Urbanization and modernization has been associated with obesity. In Northern India obesity was most prevalent in urban populations (male = 5.5%, female = 12.6%), followed by the urban slums (male = 1.9%, female = 7.2%). Obesity rates were the lowest in rural populations (male = 1.6%, female = 3.8%).

Socioeconomic class also had an effect on the rate of obesity. Women of high socioeconomic class had rates of 10.4% as opposed to 0.9% in women of low socioeconomic class. With people moving into urban centers and wealth increasing, concerns about an obesity epidemic in India are growing.

Iran

In Iran the prevalence of obesity was 26.3% in 2008. Prevalence of obesity was more among women (39.5%) than men (14.5%).

Japan

Using the WHO criteria Japan has the lowest rate of obesity among the OECD member countries at 3.2%. However, as Asian populations are particularly susceptible to the health risks of excess adipose tissue the Japanese have redefined obesity as any BMI greater than 25. Using this cut off value the prevalence of obesity in Japan would be 20%, a threefold increase from 1962 to 2002. A 2008 report stated that 28.6% of men and 20.6% of women in Japan were considered to be obese.

Pakistan

Changing lifestyles, owing to urbanisation, as well as diet issues are the main reasons for obesity in Pakistan. According to a recent study, approximately one out of four Pakistani adults (or 22.2% of individuals) are classified as obese.

Taiwan

In 2002, 15% of children from 6 to 12 years of age were overweight; by gender, 15.5% of males and 14.4% of females were overweight. In the same age range, 12% of children were obese; by gender, 14.7% of males and 9.1% of females were categorized as obese. In 2005, 14.9% children from 6 to 12 years of age were overweight; by gender, 15.85% of males and 14.02% of females were overweight. 10.3% were categorized as obese; by gender, 10.92% of males and 9.73% of females were categorized as obese.

Based on these numbers, the trends were inconclusive, although with more than 10% of the age group being obese, obesity does appear to be a problem.

Europe

Rates of obesity in the Netherlands between 1981 and 2006.

 

Between the 1970s and the 2000s, rates of obesity in most European countries have increased. During the 1990s and 2000s, the 27 countries making up the EU reported rates of obesity from 10–27% in men and from 10–38% in women.

The most recent combined Eurostat statistics, for 2009, show that, among the 19 EU Member States for which data are available, the proportion of obese people in the adult population varied in 2008/9 between 8.0% (Romania) and 23.9% (UK) for women and between 7.6% (Romania) and 24.7% (Malta) for men. Overall the UK had the highest proportions, and Romania the lowest. Men, the elderly and people with lower educations also have significantly higher obesity rates.

United Kingdom

In the UK the rate of obesity has increased about fourfold over the last 30 years, reaching levels of 22–24% in 2008/9. The United Kingdom now has the highest rate of obesity in Europe. 

Year	Percent males obese	Percent females obese
1980	6%	8%
1993	13%	16%
2000	21%	21%
2008/9	22%	24%

North America

Obesity rates as a percentage of total population in OECD member countries in the years 1996–2003 (According to BMI).

 

Epidemiological data show that, among high-income countries, obesity prevalence is highest in the United States and Mexico.

Canada

The number of Canadians who are obese has risen dramatically in recent years. In 2004, direct measurements of height and weight found 23.1% of Canadians older than 18 had a BMI greater than 30. When broken down into degrees of obesity, 15.2% were class I (BMI 30–34.9), 5.1% were class II (BMI 35–39.9), and 2.7%, class III (BMI > 40). This is in contrast to self-reported data the previous year of 15.2% and in 1978/1979 of 13.8%. The greatest increases occurred among the more severe degrees of obesity; class III obesity increased from 0.9% to 2.7% from 1978/1979 to 2004. Obesity in Canada varies by ethnicity; people of Aboriginal origin have a significantly higher rate of obesity (37.6%) than the national average.

In children obesity has substantially increased between 1989 and 2004 with rates in boys increasing from 2% to 10% and rates among girls increasing from 2% to 9%.

Mexico

Mexico has one of the highest rates of obesity among OECD countries, second only to the United States. To combat the epidemic, in 2014 Mexico implemented new taxes levied on food with excessive energy content and on sugar-sweetened beverages.

United States

The increase in obesity rates in the US as seen from 1985 to 2010 to the point where every state has at least a 20% obesity rate has caused it to become a significant focus of public health in recent years.

 

The percent of people per state with a BMI greater than 30 from 2011.

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Obesity rates in the United States have nearly tripled since the 1960s. In 1962, about 13% of adult Americans were obese, and by 2002, obesity rates reached 33% of the adult population. According to the National Health and Nutrition Examination Study collected between the 1970s and 2004, the prevalence of overweight and obesity increased steadily among all groups of Americans. The numbers continue to rise; as of 2007, 33% of men and 36% of women were obese, and by 2015–2016, 39.6% of the total adult population (37.9% of men and 41.1% of women) had obesity. Obesity rates vary between diverse social groups, with some racial groups and low-income individuals more likely to be obese while other minorities show lower rates. As of 2014 the rates were as low as 12% for non-Hispanic Asian women and as high as 57% among African American women.

The incidence of obesity also varies with geography. The American South has been referred to as the "Stroke belt", "Obesity belt", or "Diabetes belt", to reflect the fact that residents of the region have high rates of these three conditions, compared to people of the same race/ethnicity elsewhere in the country.

Based on a study in 2008, estimates of obesity that rely on self-reported data arrive at a rate of 22% among non-Hispanic white females, whereas studies that involve direct measurement show that the rate was closer to 34% at that time.

The prevalence of class III (morbid) obesity (BMI ≥40) has increased the most dramatically, from 1.3% in the late 1970s, to 2.9% in 1988-94, to 4.7% in 2000, to 5.7% in 2008, and to 7.7% in 2014. Among African American women, its prevalence is estimated to be as high as 17%.

The rate of increase in the incidence of obesity began to slow in the 2000s, but as of 2014, obesity, severe obesity, and obesity in children continued to rise.

Prevalence of obesity between 1960 and 2004 in the USA.

Obesity is one of the leading health issues in the United States, resulting in about 300,000 excess deaths per year. However, in 2005 using different methodology, research at the Centers for Disease Control and Prevention produced a nationwide estimate of 129,000 excess deaths per year relative to individuals with a BMI of 21 to 25.

South America and the Caribbean

Surveys in different Caribbean countries found that 7-20% of males and 22-48% of females over the age of 15 are obese. Trinidad and Tobago has the highest obesity in the Caribbean, with over 30% of its adult population overweight, ranking the country sixth in the world. The Bahamas have a major obesity epidemic: 48.6% of people between 15 and 64 years old are obese. A female adolescent from the Bahamas is more likely to be overweight than her male counterpart. In Jamaica, 7.2% of men over the age of 20 are obese, while 31.5% of women are obese.

Oceania and the Pacific

According to 2007 statistics from the World Health Organization (WHO), Australia has the third-highest prevalence of overweight adults in the English-speaking world.

Australia

According to self-reported and measured results of the 2007–2008 National Health Survey, 61% of Australians were overweight (above a 25 BMI), with 24% falling into the "obese" category (above a 30 BMI). Men were more likely to be overweight (67.7%) and obese (25.5%) than women (30.9% and 23.4% respectively).

New Zealand

Obesity in New Zealand has become an important national health concern in recent years, with high numbers of people afflicted in every age and ethnic group. In 2011/12, 28.4% of New Zealand adults were obese, a number only surpassed in the English-speaking world by the United States.

South Pacific

Many of the island nations of the South Pacific have very high rates of obesity. Nauru has the highest rates of obesity in the world (94.5%) followed by Samoa, the Federated States of Micronesia, and the American Samoa. Being big has traditionally been associated with health, beauty, and status and many of these beliefs remain prevalent today.