Insulin is a hormone produced by the beta (β)-cells of the pancreas and regulates the way your body uses and stores glucose. Glucose is the main type of sugar and source of energy which we get from food. Diabetes mellitus simply called diabetes is a chronic (or long-lasting) disease described by higher levels of glucose in the blood. This happens when the body cannot produce insulin in sufficient amounts or does not effectively use the insulin it produces. Consequently, glucose is not absorbed into the cell and results to high blood sugar levels. This affects the body’s ability to transform food into energy.

High level of blood sugar is also known as hyperglycemia while low levels are referred to as hypoglycemia. Hyperglycemia can be temporal and does not mean you have diabetes, but persistent hyperglycemia will result to diabetes. Persistent and high levels of glucose in the blood will cause it to accumulate and damage tissues or organs, and also weaken blood vessels. Secondly, it will not be available for energy causing the patient to feel weak and tired.

Types of Diabetes

There are three major types of diabetes namely, type 1 diabetes (T1D), type 2 diabetes (T2D), and gestational diabetes mellitus (GDM). But other specific types also exist and are classified based on their cause. This includes latent autoimmune diabetes of adulthood (LADA), maturity-onset diabetes of the young (MODY), neonatal diabetes mellitus (NDA), steroid induced diabetes and cystic fibrosis diabetes. Because of their origin and complexity, it is usually hard to diagnose and distinguish them from the major types.

Type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) also called insulin-dependent, or juvenile-onset diabetes is an autoimmune condition in which the immune system attacks and destroys the β-cells of the pancreas which are responsible for producing insulin. As a result, the pancreas either does not produce or produces insufficient insulin. T1D is not very common and accounts only for 5 to 10% of all diagnosed cases.

Type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) also called non-insulin dependent, or maturity-onset diabetes mellitus is a disease where the pancreas makes normal or elevated levels of insulin, but the cells of the body do not respond to the insulin. These cells are said to be insulin resistant. As a result, blood glucose concentration stays higher than normal, especially after a meal. T2D is more common than T1D and accounts for about 90% to 95% of all diagnosed cases.

Gestational diabetes mellitus (GDM)

Gestational diabetes mellitus (GDM) is not type 1 or type 2 diabetes. It is any form of glucose intolerance disorder which occurs only during pregnancy and typically resolves after birth. It is however a warning sign for T2D which manifest within 5 to 10 years after delivery. GDM affects about 7 to 10% of pregnant women worldwide.

What is Prediabetes?

Prediabetes (or borderline diabetes) is a health condition in which blood sugar (or glucose) levels are high but not high enough to be classified as T2D. It will lead to T2D if left untreated. Fortunately, prediabtes can be completely treated or reversed through healthy diet, physical exercise, and maintaining a healthy weight.

Can I have both type 1 and type 2 diabetes?

Yes. You can develop both T1D and T2D, and this is referred to as double diabetes. Double diabetes occurs when someone with T1D goes on to develop insulin resistance which then leads to T2D. About 85% of cases of T2D occur in people who are obese. Obesity causes your body to produce more insulin and with time, this leads to insulin resistance. Therefore, obesity is the main reason for double diabetes.

Does type 3 diabetes exist?

In 2008, researchers proposed the term type 3 diabetes  (T3D) to represent Alzheimer’s disease. This is because Alzheimer’s disease has molecular and biochemical features that overlap with both T1D and T2D but selectively involves only the brain. However, the term type 3 diabetes is not officially recognized and hence it is not a medical condition.

Similarly, many researchers and healthcare professionals have coined the term type 3a through to type 3h diabetes to diagnose and classify different complications of diabetes mellitus. For example, type 3c represents diabetes which develops due to any condition or illness which affects the pancreas. Again, none of these classifications are officially recognized either by the World Health Organization (WHO) or the American Diabetes Association (ADA).

Symptoms of diabetes

Type 1 and type 2 diabetes share common symptoms, and this includes:

  • Frequent urination: This occurs as a way for your kidney to attempt to expel excess sugar.
  • Increase thirst: It occurs because of frequently urination and dehydration.
  • Increase hunger: This happens because glucose is not available for energy due to the inability of the body to produce insulin (T1D) or use insulin (T2D). This makes the body to be low in energy and hence creates a feeling of increase hunger.
  • Unusual fatigue and body weakness: This occurs because your body is low in energy and cannot make use of glucose. In addition, it spends most of the little energy it has attempting to expel excess glucose out of the body.
  • Unexplainable weight loss: Because insulin is not available to break down sugar, your body starts to burn fat and muscle for energy causing weight loss.
  • Cuts and wounds take longer to heal: This happens because excess sugar weakens and damage blood vessels. Hence, there is poor circulation of blood to cells and tissues which causes slow healing.
  • Genital itching or thrush: Excretion of excess sugar through the genitals create a fertile ground for yeast infections.
  • Blurred vision: This results from accumulation of excess glucose in the lenses of the eye.
  • Numbness or tingling in the hands or feet: High sugar levels weaken and damage blood vessels making them unable to deliver oxygen and nutrients to the brain. The result is nerve damage which comes with a feeling of tingling or numbness.

How to distinguish between symtoms of type 1, type 2 and gestational dibaetes mellitus

Although type 1 and type 2 diabetes share common symptoms, it is possible to tell the difference. Symptoms of type 1 diabetes are very sudden, and you will know immediately when you start experiencing them. However, symptoms of type 2 diabetes occur very slowly overtime such that you might not notice them.

GDM hardly causes noticeable signs and symptoms. Blood test is mostly used for diagnosis. However, increased thirst and more-frequent urination are possible symptoms.

Treatment of type 1, type 2, and gestational diabetes.

diabetes treatment

Type 1 diabetes (T1D) cannot be permanently treated but you can still live a normal life and avoid complications by careful management of your blood sugar levels. Similarly, type 2 diabetes (T2D) cannot be cured but unlike T1D, it can be prevented and put into remission by regularly monitoring your blood sugar level, doing regular exercise, eating healthy diet, and using some medications. Luckily, gestational diabetes mellitus (GDM) can be treated. Treatment of GDM aims to keep blood glucose (or sugar) levels normal. This can be achieved through medications, scheduled exercises, special meals, daily blood glucose testing and insulin injections. In most cases GDM will go away immediately after delivery but for some, it can develop into T2D immediately or 5 to 10 years post-delivery.

How to Prevent type 1, type 2, and gestational diabetes

There exist no natural or medical intervention that can be used to prevent T1D completely. However, T2D can be prevented through regular exercise, maintaining a healthy body weight, eating healthy, stop smoking, and going for regular checkups. While some factors which contributes to GDM such as race or ethnicity, maternal age, sickness, or family history of diabetes are beyond your control, in most cases GDM can be prevented by maintaining a healthy body weight and exercising regularly.

Risk factors for Diabetes

The following factor(s) puts anyone at risk of developing T1D, T2D or GDM:

  • Obesity or overweight.
  • Physical inactivity.
  • Except for type 1 diabetes, the older you get the higher your chances of developing diabetes.
  • Family history of diabetes. Having a father, mother, brother, or sister with diabetes also increases your chances of developing diabetes.
  • Race and ethnicity. Being Caucasian (White), Black, Latino, Asian, or Chinese will affect your chances of getting diabetes.
  • Smoking.
  • Presence of autoimmune diseases or infections.

How to Diagnose Diabetes?

Diabetes can be diagnosed by conducting specific glucose tests that measure blood glucose (or sugar) levels. In addition to glucose tests, physical examination, presence or absence of symptoms and medical history must be considered. Also, factors which alter blood sugar levels such as medications, certain diseases, or vigorous exercise are well-thought-out before confirming diagnosis.

To confirm diagnosis based on glucose levels, a given test needs to be repeated on a different day. If on the same day, then two different tests must be used. Although the diagnosis is made based on blood tests, the presence of sugar or ketone in urine may also be an indication of diabetes.

Healthcare professionals mostly use four types of tests to diagnose and manage diabetes. This includes fasting blood sugar (FBS) test, glucose tolerance test (GTT), hemoglobin A1C (HbA1C) and random blood sugar (RBS) test. Blood sugar or glucose values are reported in mg/dl or mmol/L. To covert from mg/dl to mmol/L simply multiply by 0.0555. But to convert from mmol/L to mg/dl, then divide by 0.0555.

Fasting blood sugar (FBS) test

FBS test measures your blood sugar levels after an overnight fast in which you must not eat or drink anything except water for at least 8 hours before the test. FBS levels ≥ 126 mg/dL (7.0 mmol/L) confirm the diagnosis of diabetes.

Glucose tolerance test (GTT)

GTT is used to evaluate how your body moves glucose from the blood into the tissues or cells. Also, the patient must not eat for at least 8 hours before the test. With glucose tolerance test, fasting blood sugar is first measured after which the patient is given a drink containing 75 g of glucose. Blood glucose levels are then measured at 1-hour and 2-hour postprandial. Blood glucose values obtain after 2 hours are used for diagnosis. Fasting blood glucose values ≥ 126 mg/dl or 2-hour postload glucose values ≥ 200 mg/dl confirm diagnosis of diabetes.

Hemoglobin A1C (HbA1C)

HbA1C test measures the average amount of blood sugar attached to hemoglobin over a period of 3 months. HbA1C values ≥ 6.5% confirm diagnosis of diabetes.

Random blood sugar (RBS)

RBS measures your blood glucose level at any time of the day regardless of whether you have eaten or not. RBS values ≥ 200 mg/dL (11.1 mmol/L) confirm diagnosis of diabetes.

The table below summarizes the diagnoses of diabetes from specific glucose tests.

Type of Test Normal Prediabetes (Impaired glucose tolerance) Diabetes
Fasting blood sugar ≤ 99 mg/dL (5.5 mmol/L) 100 to 125 mg/dL (5.6 to 6.9 mmol/L ≥ 126 mg/dL (7.0 mmol/L)
Glucose tolerance test
(2-h postload)
< l 140 mg/dL 140 mg/dL to 199 mg/dl ≥ 200 mg/dL
Hemoglobin A1C < 5.7% 5.7% to 6.4% 6.5% or higher
Random sugar
*Results shown is for before a meal.
80 mg/dL to 140 mg/dL 140 mg/dL to 199 mg/dl ≥ 200 mg/dL (11.1 mmol/L)


Normal blood glucose or sugar level is between 80 mg/dL to 140 mg/dL. But 1 to 2 hours after a meal, it can be as high as 180 mg/dL. However, fasting blood glucose between 100 and 125 mg/dL and a glucose tolerance value of less than 140 mg/dL at 2 hours indicates impaired fasting glucose.

A pregnant woman has GDM if fasting blood glucose is ≥ 92 mg/dl, 1 hour glucose level is ≥ 180 mg/dl, and 2 hours glucose level is ≥153 mg/dL. If only one of the values above are higher than normal, then the test needs to be repeated on a different day. But if two or more of the values are higher than normal then you have GDM.

How to distinguish type 1 and type 2 diabetes based on glucose test

Blood glucose tests alone cannot confirm diagnosis of T1D. To distinguish T1D from other types, the blood will also be evaluated for the presence of autoantibodies which is an indication of an autoimmune disease as in the case with T1D. Other factors such as the onset of symptoms are also taken into consideration. Symptoms of T1D are very sudden.

Diabetes remission

Diabetes remission also termed “reversing type 2 diabetes” is when your blood sugar levels go down below the diabetes range, such that you no longer need to continue taking medication. It can be achieved through losing weight and staying physically active. It is however not clear if everyone with  T2D can undergo remission. Also, diabetes remission is not a cure for T2D as there is no evidence that remission is permanent, and your blood sugar levels will rise again if not maintained. Therefore, always go for regular checkup even when you are under remission.

Although the term diabetes remission is mostly used to refer to T2D. People with T1D can also undergo a temporal or partial remission also called the honeymoon in T1D. This occurs shortly after the onset or diagnosis of T1D.

GDM will go away immediately after birth in some cases. Remission for gestational diabetes is also possible. A 1985 study reported an insulin-dependent pregnant diabetic needing no insulin during most of her pregnancy.

Differences between Diabetes Mellitus and Diabetes Insipidus

Diabetes insipidus is a rare and treatable condition which can be chronic or acute. It is caused by inadequate secretion of antidiuretic hormone (ADH) or an insufficient renal response to adequate levels of ADH. Diabetes mellitus (DM) and diabetes insipidus (DI) are not related although both share some similar signs and symptoms. In DM, there is higher level of glucose in the blood which the kidney tries to remove by passing it through urine. While in DI your blood glucose is normal, but your body produces so much water that the kidney cannot retain and concentrate. Excess water is then passed out as urine (pee).