 India has been undergoing a change in its health from the past several decades. This can be noted from the increase in the non-communicable disease to the decrease in the infectious diseases. One of the most prominent communicable diseases reported in present-day India is diabetes mellitus. To know about diabetes mellitus and also about the four different types of it, watch this video fully. First of all, let us see what is diabetes? Diabetes mellitus. It is more commonly known as diabetes. It is nothing but a disease that happens when the body can't process blood sugar, which is also known as glucose. See, when we eat, our body breaks the food into glucose. Then the glucose is sent into the bloodstream to fuel the cells in the body with energy. This triggers the pancreas to release a hormone called insulin. This insulin only helps the glucose to enter the cells. What we have seen till now is the normal process which happens in everyone's body. Then what will happen in case of diabetes? See, in case of diabetes, the pancreas either won't make enough insulin or the body cells won't use the insulin produced by the pancreas properly. This leads to high levels of glucose in the blood, which in turn causes symptoms of diabetes. Now, this is the basics about the diabetes. Now, let us see its types. See, there are four different types of diabetes. We will see them one by one. Firstly, let us look at type 1. See, type 1 diabetes occurs when the pancreas doesn't make enough insulin. This means that one has to take insulin every day. It is usually diagnosed in kids, teens and young adults. Also note that it can happen at any age. See, it is caused because of the autoimmune condition. This means that the immune system attacks the cells that produce insulin in the pancreas and destroys them. Other factors that cause type 1 diabetes include genetics and environmental factors. See, a viral infection can also trigger type 1 diabetes. I am saying it once again. Here note the point that it can happen at any age. So if a question comes in the prelims stating that type 1 diabetes happens only in young adults, the statement is wrong. It can happen at any time. This is all about type 1 diabetes. The next one is type 2. Type 2 diabetes occurs when the pancreas is not making enough insulin or the body isn't using the insulin well. This type is more common over the age of 40. But know that this can also happen at any age. See, the cause of type 2 is insulin resistance. It is a condition where the cells in the body do not respond to insulin and the cells will not be able to take glucose from the blood. So the pancreas pumps out more insulin to get blood sugar into cells. This is because insulin only helps glucose to enter the cells. Over time, cells stops responding to insulin. This is only called as insulin resistance. And eventually the pancreas gives up producing insulin and blood sugar will keep on rising. This is all about the second type. Now moving on to see the third type. The third one is gestational diabetes. It is developed during pregnancy. It usually disappears after the baby is born. But it increases the risk of developing type 2 diabetes later on. Now we will see its cause. When a person is pregnant, the placenta makes more hormones. In some women, these hormones can cause insulin resistance which leads to high blood sugar. This is all about the third type. Finally, pre-diabetes. Technically, it is not a distinct type of diabetes. So what do you think it is? See, it is a condition where a person has elevated blood sugar levels that aren't high enough to qualify as type 2 diabetes. So this pre-diabetes increases the risk of developing type 2 diabetes. With this, we have seen all the four different types of diabetes.