An easy guide for understanding type 1 and type 2 diabetes

The prevalence of diabetes has skyrocketed from 108 million people in 1980 to over 422 million in 2014. Most people with diabetes have type 2 (90-95%), whereas a minority have type 1 (5-10%). Type 1 diabetes (T1D) used to be referred to as ‘juvenile-onset’ whereas type 2 diabetes (T2D) was known as ‘adult-onset’ diabetes. Both these terms were frequently used in the past as T1D was mostly observed in young children, while T2D was only seen in adults. However, this is a BIG myth as both types of diabetes can occur at any stage throughout life. Now we are seeing a dramatic increase in the incidence of T2D in young children, something that was rarely seen in this age group a few decades back.

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Figure 1. Pie chart showing the distribution of individuals with type 1 and type 2 diabetes. The majority of diabetics have type 2 (90%), while around one in ten people with diabetes have type 1.   

The two key words required to comprehend diabetes are ‘insulin’ and ‘glucose’. In healthy individuals, the hormone insulin is released by the pancreas and allows the body to efficiently use glucose as a fuel that provides cells with energy. However, a chronic condition known as diabetes develops when things start to go wrong with the production or function of insulin. Diabetes is characterised by an incapacity of the body to utilise and transport glucose into cells, consequently causing the accumulation of this sugar in the bloodstream. Over time, this build-up of glucose damages the small blood vessels lining various delicate organs such as the eyes and kidneys. 

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Figure 2. Dietary carbohydrates are broken down into the small sugar molecule glucose, which can then be absorbed into the bloodstream. a) In a healthy individual, insulin is secreted from the pancreas to allow the uptake of glucose into cells to use it as an energy source. b) But in diabetics, insulin is either not working properly or completely absent and as a consequence glucose is not taken up by cells. The big problem of this is that glucose accumulates in blood vessels and damages vital organs over time.

The core distinguishing feature between T1D and T2D diabetes is whether the pancreas can secrete insulin or not. In type T1D the body cannot produce any insulin due to the loss of pancreatic beta cells which normally produce this hormone. The death of these cells is caused by an auto-immune response in which the body secretes its own antibodies against the pancreas! No one knows exactly what causes the body to attack its own beta cells, but new research has suggested that genetics, viral infections and vitamin D deficiency plays a role. 

Meanwhile, in T2D the pancreas is able to produce insulin but the cells across the body don’t respond to the actions of this hormone. Having T2D is like having the key (insulin), but the lock on the door (receptors) has been changed so that it’s not longer possible to get the glucose into the cell (house). In some individuals with T2D, the pancreas produces extra insulin to compensate for the lack of response (known as insulin resistance). However, over time many type 2 diabetics lose their ability to synthesise insulin.

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Figure 3. The pancreas of type 1 diabetics doesn’t produce insulin (left), while that of type 2 diabetics can (right). However, the problem in T2D is insulin resistance; where cells stop responding to the actions of this hormone. Nevertheless, the pancreas will progressively stop producing insulin if T2D is not adequately managed.

Individuals with T1D are rapidly diagnosed of their condition, while individuals with T2D can take a very long time to realise they have diabetes. This is because T1D is a more serious condition and untreated patients rapidly develop hyperglycemia (high blood glucose), causing uncomfortable symptoms e.g. dizziness, blurred vision and infections. The severity of their symptoms makes type 1 diabetics to quickly seek medical advice, so their condition is quickly exposed. Whereas, in T2D the levels of glucose may only be slightly higher than the recommended range and individuals may not get any symptoms; significantly delaying their diagnosis.   

The treatment options for T2D will vary drastically depending on the severity of the condition, whereas the management of T1D is pretty much the same at all times. As people with T1D cannot make any insulin, the treatment involves providing injections with the hormone to stabilise blood glucose levels. Also, patients must constantly monitor their glucose levels throughout the course of the day using skin prick tests.

On the other hand, type 2 diabetics usually don’t need to take insulin medications at the early stages of the disease. Instead, doctors will recommend lifestyle changes such as exercise, eating a low carb-diet and maintaining an optimal body weight. However, as T2D progresses, the body gradually produces less insulin and patients will require hormone replacement therapy injections like in T1D. 

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Figure 4. Differences and similarities in the treatment of diabetes. a) Type 1 diabetics must be given insulin injections as their pancreas cannot make this hormone. Also, they must constantly measure their glucose levels to ensure they are stable. b) Meanwhile, the treatment for T2D will differ depending on what stage the condition is diagnosed. When the disease is at an early stage, lifestyle modifications such as healthy eating and frequent exercise are the best line of therapy. c) Furthermore, doctors may prescribe a medicine called metformin to control glucose levels and to protect the heart. d) Unfortunately, when T2D progresses too much and the pancreas stops producing insulin, the treatment becomes very similar to that of T1D. 

Although anyone can develop T1D, we can delay the onset and even prevent T2D with a healthy lifestyle. Being obese, sedentary and consuming a sugar rich diet are major risk factors that increase the likelihood of developing T2D. If people moved more, ate better and maintained a healthy weight, the rates of diabetes would plummet.

Overall, diabetes is a chronic and extremely serious medical condition that can lead to blindness, kidney failure, stroke or death if left unmanaged. To conclude, T1D is the more severe form as it’s not possible to cope without medication, whereas T2D may be managed effectively for an entire lifetime without the need to use insulin.

References

American Diabetes Association. (2010). Diagnosis and Classification of Diabetes Mellitus. Diabetes Care, 33(Suppl 1), S62–S69.

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