Type 2 diabetes occurs when the body produces too little insulin and does not respond to insulin correctly.¹ Insulin is the hormone the pancreas makes to move glucose from the bloodstream into cells for energy.^2,3 It is also essential for the breakdown of protein and fat.

In type 2 diabetes, the muscles, liver and fat cells become insulin-resistant, making it challenging to take glucose from the bloodstream. The pancreas produces more insulin to compensate for this and keeps blood glucose levels within the normal range. However, over time, the pancreas cannot keep up, and blood glucose gradually rises above normal, first to the prediabetes stage and eventually to type 2 diabetes. An individual may have insulin resistance for 10-15 years before type 2 diabetes develops.⁴

How many people does type 2 diabetes affect globally?

Type 2 diabetes is the most common type of diabetes, affecting about 90% of people with diabetes globally. According to the International Diabetes Federation, an estimated 536.6 million adults aged 20-79 live with diabetes, and that figure is expected to rise to 783.2 million in 2045.⁵ An estimated 240 million live with undiagnosed diabetes globally, of which almost 90% live in low- and middle-income countries. In Africa, South-East Asia and the Western Pacific, over 50% of people with diabetes are undiagnosed.⁵

Prevalence of diabetes in adults (20-79 years) in IDF Regions5
	Number of people with diabetes (in millions)
IDF Region	2021	2045
Western Pacific	205.6	260.2
Africa	23.6	54.9
North America and Caribbean	50.5	62.8
Middle East and North Africa	72.7	135.7
South and Central America	32.5	48.9
Europe	61.4	69.2
Southeast Asia	90.2	151.5
World	536.6	783.2

Who is more likely to get type 2 diabetes? ^1,6

People with certain genetic and lifestyle risk factors are more likely to develop prediabetes. Some of these risk factors include:

• Age >40 in Caucasians or over 25 in African-Caribbean, Black African, Chinese or South Asian)
• Overweight (BMI ≥ 25 kg/m² in Caucasians or ≥23 kg/m² in Asians)
• High waist circumference
• Having a first-degree relative (parent, sibling or child) with diabetes
• Being from the Pacific Island or of African American, Latino, Native American, or Asian American descent
• History of cardiovascular disease
• High blood pressure (≥ 130/80 mmHg or taking blood pressure medication)
• Low HDL ‘good’ cholesterol (< 35 mg/dL [0.9 mmol/L) and/or high triglycerides >250 mg/dL (2.82 mmol/L)
• Polycystic ovary syndrome
• Physical inactivity
• Having conditions associated with insulin resistance (severe obesity, acanthosis nigricans)
• History of diabetes during pregnancy (gestational diabetes)
• Smoker
• Mental health conditions

What are the symptoms of diabetes?^7,8

Diabetes symptoms can take many years to develop. Some individuals have no symptoms and may only experience symptoms once they develop other health problems. When present, the symptoms of type 2 diabetes include:

• Feeling extremely thirsty with a dry mouth
• Urinating frequently, especially at night
• Feeling fatigued
• Slow healing wounds
• Frequent skin infections
• Frequent genital infections or itching
• Blurred vision
• Tingling or numbness in hands and feet

What causes type 2 diabetes?

Scientists do not entirely understand the causes of type 2 diabetes. However, there is a strong link between type 2 diabetes and overweight and obesity, increasing age, ethnicity, family history, and genetic and environmental factors.^1,5 Most people with type 2 diabetes have high body fat, especially around the abdomen; this, in addition to being physically inactive and eating an unhealthy diet, contributes to developing the condition.¹

How do doctors test and diagnose type 2 diabetes?

Doctors can diagnose type 2 diabetes with different tests. These are:⁵

1. Fasting blood glucose test – which measures blood glucose levels after an overnight (at least 8 hours) fast.
2. Oral glucose tolerance test (OGTT), which measures blood glucose two hours after drinking a fluid containing 75g of glucose. This test checks how well your body handles sugar.
3. Glycated haemoglobin (HbA1c) test, which measures the average blood sugar over the past two to three months. This test measures the amount of sugar attached to your red blood cells.
4. Random blood glucose test

Your doctor will diagnose prediabetes if:

• Fasting blood glucose is ≥7 mmol/L (126 mg/dL)
• OGTT is >11.1 mmol/L (≥200 mg/dL)
• HbA1c is >6.5% (≥48 mmol/L
• Random blood glucose >11.1 mmol/L (≥200 mg/dL) with classic signs of high blood sugar

Diagnosis of Type 2 Diabetes
TEST	Result
Fasting blood glucose	≥7 mmol/L (126 mg/dL)
Oral glucose tolerance test	≥11.1 mmol/L (200 mg/dL)
HbA1c	≥6.5% (48 mmol/L)
Random blood glucose	≥11.1 mmol/L (200 mg/dL)

How can I manage type 2 diabetes?

Managing diabetes involves managing weight, blood pressure, cholesterol and blood glucose.⁹ The best way to achieve this is by eating a healthy diet, increasing activity, maintaining a healthy weight, quitting smoking and getting enough sleep.⁹

There is no specific diet for type 2 diabetes; any diet providing a variety of nutrient-dense foods (fruits, starchy and non-starchy vegetables, lean meats, nuts, seeds, legumes, fish and poultry) in appropriate portions and limits foods high in sugar, salt and saturated fat, such as chocolate, sweets, pastries, crisps, and desserts is suitable.⁹

Weight loss of at least 5% of body weight is advised for most people with type 2 diabetes and overweight and obesity.⁹ However, additional weight loss may further improve diabetes management and reduce the risk of cardiovascular disease.⁹  

Aim for at least 150 minutes of activity each week, including aerobic exercises such as brisk walking, jogging, running or cycling and resistance-training exercises, such as weight-lifting and callisthenics.⁶ Flexibility exercises such as yoga and Pilates are also helpful as they can help improve joint mobility, reduce the risk of injury and improve overall physical performance. Exercise has many benefits; it improves mood, and increases muscle mass and insulin sensitivity, allowing the body to regulate blood sugar levels better.

What medications are used to treat type 2 diabetes?

Over time, diet and lifestyle may not be sufficient to control diabetes, and some individuals may need medication. Metformin is usually the first line of treatment. Still, other medications, such as sulphonylureas (e.g. gliclazide), sodium-glucose cotransporter 2 inhibitors (SGLT2 inhibitors, e.g. empagliflozin), and dipeptidyl peptidase 4 (DPP-4) inhibitors (e.g. sitagliptin), may be added if metformin fails to control blood sugar alone.^10,11

The additional medication a doctor prescribes depends on a range of factors, including the patient’s preferences, the duration of diabetes, if weight loss is desired or if a person is at high risk of hypoglycaemia or has cardiovascular and/or kidney disease and other health conditions.^10,11

What other health problems can arise in people with type 2 diabetes?

People with type 2 diabetes may experience several health problems if their blood sugar is not managed correctly. It can cause damage to various body parts, such as the heart, eyes, feet, kidneys, teeth, and nerves. Moreover, it can also impact sexual health and increase the risk of certain cancers.¹² Additionally, individuals may experience hypoglycaemic episodes (when blood sugar levels become too low) or hyperglycaemic episodes (when blood sugar levels become too high). A hyperosmolar hyperglycaemic state can also occur if a person is dehydrated with very high blood sugar.

REFERENCES

1. Galicia-Garcia, U., Benito-Vicente, A., Jebari, S., Larrea-Sebal, A., Siddiqi, H., Uribe, K. B., Ostolaza, H., & Martín, C. (2020). Pathophysiology of Type 2 Diabetes Mellitus. International Journal of Molecular Sciences, 21(17). https://doi.org/10.3390/ijms21176275.
2. Rahman, M. S., Hossain, K. S., Das, S., Kundu, S., Adegoke, E. O., Rahman, M. A., Hannan, M. A., Uddin, M. J., & Pang, G. (2021). Role of Insulin in Health and Disease: An Update. International Journal of Molecular Sciences, 22(12). https://doi.org/10.3390/ijms22126403.
3. Rachdaoui, N. (2020). Insulin: The Friend and the Foe in the Development of Type 2 Diabetes Mellitus. International Journal of Molecular Sciences, 21(5). https://doi.org/10.3390/ijms21051770.
4. Freeman, A.M., Acevedo, L.A., Pennings, N. (2023) Insulin Resistance. Available: https://www.ncbi.nlm.nih.gov/books/NBK507839/ Accessed: 11 October 2023.
5. International Diabetes Federation. IDF Diabetes Atlas, 10^th edn. Brussels, Belgium: 2021. Available at: https://diabetesatlas.org.
6. ElSayed, N.A., Aleppo, G., Aroda, V.R., Bannuru, R.R., Brown, F.M, et al., (2022) Classification and diagnosis of diabetes: Standards of Care in Diabetes – 2023. Diabetes Care, 46 (Supplement_1): S19-S40. https://doi.org/10.2337/dc23-S002.
7. Good to know: Diabetes Symptoms and Tests (2020). Clinical Diabetes: A Publication of the American Diabetes Association, 38(1): 108. https://doi.org/10.22337/cd20-pe01.
8. American Diabetes Association (2010). Diagnosis and Classification of Diabetes Mellitus. Diabetes Care, 33(Suppl 1), S62. https://doi.org/10.2337/dc10-S062
9. ElSayed, N.A., Aleppo, G., Aroda, V.R., Bannuru, R.R., Brown, F.M., Bruemmer, B., Collins, B.S., et a., (2022) Obesity and weight management for the prevention and treatment of type 2 diabetes: Standards of Care in Diabetes – 2023. Diabetes Care, 46(Supplement_1): S128-S139. https://doi.org/10.2337/dc23-S008.
10. ElSayed, N.A., Aleppo, G., Aroda, V.R., Bannuru, R.R., Brown, F.M., Bruemmer, B., Collins, B.S., et a., (2022). Pharmacologic approaches to glycaemic treatment: Standards of Care in Diabetes– 2023. Diabetes Care, 46(Supplement_1): S140-S157. https://doi.org/10.2337/dc23-S009.
11. Pfeiffer, A.F.H., & Klein, H.H. (2014) The treatment of type 2 diabetes. Deutsches Arzteblatt International, 111(5): 69-82. https://doi.org/10.3238/arztebl.2014.0069.
12. Nellaiappan, K., Preeti, K., Khatri, D.K., & Sing, S.B. (2022) Diabetic complications: an update on pathobiology and therapeutic strategies. Current Diabetes Reviews, 18(1): e030821192146.