Fast Facts: Type 2 Diabetes

Identify early, intervene effectively, make every contact count

P. Brown, C. Hambling

• Publisher: S. Karger
• Year: 2021
• ISBN:
  9781912776344
• Topic: Medicine
• Subtopic: Endocrinology & Metabolism

Fast Facts: Type 2 Diabetes provides a practical overview of this increasingly common health condition. Written by and for health professionals working in primary care, this colourful and accessible handbook highlights important practice points that cover: • identifying and managing those at risk of developing type 2 diabetes • multifactorial interventions to prevent and treat complications • monitoring recommendations An indispensable read for anyone wanting to get up to speed with best practice in primary care. Table of Contents: • Epidemiology • Prevention strategies • Diagnosis • Self-management • Lowering blood glucose • Hypertension and dyslipidemia • Monitoring and microvascular complications • Macrovascular complications • Special populations

1	Epidemiology

Type 2 diabetes was once thought to be a ‘disease of the West’ and a ‘disease of affluence’, but it is now increasing most markedly in the cities of low- and middle-income countries. Here, people develop the condition earlier, get sicker and die sooner than in wealthier nations. The number of people aged 20–79 years with diabetes around the world is summarized in Figure 1.1.¹

No country or ethnic group is immune to type 2 diabetes and its constellation of associated complications. Nutrient excess, obesity and a sedentary lifestyle are the principal causes of the increasing prevalence of type 2 diabetes, although factors such as genetics, environmental influences (epigenetics), increasing life expectancy and aging are also important. Obesity-related type 2 diabetes now accounts for a substantial proportion of newly recognized diabetes in the adolescent age group. Over-nutrition has been a leading cause for an increased risk of diabetes, but its effect is different in different populations. For example, South Asians have a genetic predisposition for diabetes. With excessive energy intake and a sedentary lifestyle, these individuals develop central or abdominal obesity. Visceral fat around the liver, pancreas and bowel is metabolically active and contributes to insulin resistance and reduced insulin production from fat in the pancreas.

Non-modifiable risk factors

Age. The chance of developing diabetes increases with age – most people have an increased risk beyond the age of 40 years. The prevalence of type 2 diabetes is highest in older age groups, but there is a rising tide of diabetes in young people. In England, 9% of people aged 45–54 years have diabetes compared with 23.8% of those aged over 75.² The age group 65–79 years has the highest diabetes prevalence in both women and men.

In populations of European origin, the vast majority of children and adolescents with diabetes have type 1 diabetes, but in all populations – and particularly in non-European populations – type 2 diabetes is becoming more common in this group.¹

Figure 1.1 Diabetes is a global emergency. The number of people aged 20–79 years with diabetes. Reproduced with permission from the International Diabetes Federation 2019.¹

Sex. The prevalence of diabetes in women aged 20–79 years is estimated to be 9.0%, which is slightly lower than that in men, at 9.6%.¹ By 2045, it is estimated that 10.8% of women and 11.1% of men will have diabetes.

Overall, there appear to be no differences in the prevalence of non-diabetic hyperglycemia between the sexes.

Ethnic background. Certain ethnic groups have a higher risk of developing type 2 diabetes. In the UK, compared with the general population, individuals of South Asian origin have the highest standardized risk ratio (SRR) for developing type 2 diabetes: around 2.9 among people of Indian ethnicity, below 5.5 in those with a Pakistani ethnic origin and below 5.7 in those with a Bangladeshi origin.³ The odds for type 2 diabetes is higher for women than for men across all ethnic minority groups.

Comparison of the risk profiles in South Asian and white European individuals in the UKADS (United Kingdom Asian Diabetes Study) shows that people with a South Asian background tend to have disease with earlier onset (57.0 vs 64.8 years), of longer duration before diagnosis (7.8 vs 6.3 years), with lower body mass index (BMI) (28.6 vs 31.0 kg/m²) and waist circumference (101.7 vs 105.5 cm) thresholds and higher glycosylated hemoglobin (HbA1c) (8.2% vs 7.2%).³ This is why, in the UK, screening for type 2 diabetes is advised at a younger age and lower BMI for people from black and minority ethnic groups.^4,5

Genetics/family history of diabetes. Diabetes is a complex condition. There is a strong genetic link to the risk of developing type 2 diabetes. A family history of type 2 diabetes may be considered a risk factor.

Type 2 diabetes is ‘polygenic’, meaning that it is associated with changes in multiple genes. An increasing number of genetic variants are being identified as potential contributors. There is no single combination of genes that leads to the condition; instead, the expression and combinations of numerous mutations of the problem genes have been associated with a higher diabetes risk. Epigenetic changes that disrupt metabolic homeostasis are now also being recognized as contributing to the pathogenesis of type 2 diabetes.⁶

Genetic variants explain only 10% of the heritability of type 2 diabetes and some individuals with these genetic predispositions do not develop clinical diabetes.

Gestational diabetes mellitus. Some women develop diabetes during pregnancy, and have a higher risk of developing diabetes again later in life; the lifetime risk of developing type 2 diabetes after gestational diabetes mellitus (GDM) can be up to 60%.⁷ Breastfeeding reduces this risk. Women have an increased risk of GDM if they have a close family member who has diabetes and/or are overweight or obese.

Polycystic ovary syndrome (PCOS) is a non-modifiable risk factor associated with type 2 diabetes. Of women with PCOS, around two-thirds have insulin resistance and compensatory hyperinsulinemia, which increases the risk of developing type 2 diabetes. This risk can be reduced with weight loss and physical activity.

Modifiable risk factors

Obesity and overweight. Weight gain, BMI, waist circumference and waist to hip ratio are strongly and linearly associated with risk of diabetes; obese individuals have almost ten times the risk of diabetes compared with non-obese individuals. An increase in abdominal adiposity and a decrease in peripheral muscle mass significantly contribute to the development of diabetes.

Ectopic fat in skeletal muscle, liver or pancreas can distort cellular functions, eventually leading to insulin resistance, reduced insulin secretion and, consequently, type 2 diabetes.

Diet. Any dietary habits that lead to obesity also increase a person’s chances of progressing from non-diabetic hyperglycemia (plasma glucose above normal but below the diagnostic threshold for type 2 diabetes) to diabetes. There is no specific food type that causes diabetes, but refined sugars and fat are major sources of excess calories. A diet high in saturated fatty acids and low in dietary fiber, wholegrain cereals and low-glycemic-index carbohydrates increases the risk of type 2 diabetes. A progressive hyperglycemic state is caused by frequent high-carbohydrate consumption – the skeletal muscle and adipose tissue become overloaded with glucose and are consequently less able to take up more glucose. Hyperglycemia thereby contributes to insulin resistance, prediabetes and, eventually, diabetes.

Stress activates the sympathetic autonomic nervous system – ‘fight or flight’. Cortisol increases and acts as a counter-regulatory hormone to insulin, elevating blood glucose. Chronic stress leads to chronic hyperglycemia which, in turn, increases insulin resistance and triggers type 2 diabetes in predisposed individua...

Table of contents

• Cover
• Title Page
• Copyright
• Contents
• Abbreviations
• Introduction
• 1. Epidemiology
• 2. Prevention strategies
• 3. Diagnosis
• 4. Self-management
• 5. Lowering blood glucose
• 6. Hypertension and dyslipidemia
• 7. Monitoring and microvascular complications
• 8. Macrovascular complications
• 9. Special populations
• Useful resources
• Index