Diabetes and obesity

• Type 1 DM is characterized by destruction of the pancreatic beta cells. It is autoimmune system disorder, then T cells of human body cannot recognize the difference between own cells and foreign cells, causing the body to mistakenly attack normal cells. Type 1 DM is also called insulin-dependent diabetes.

• In type 1 DM, signs and symptoms often arise suddenly. Type 2 DM usually develops more insidiously, often existing for years without detection until diagnosed during a routine medical examination or care for other conditions.

The most commonly identified signs and symptoms of diabetes are referred to as the three polys:

1. Polyuria (i.e., excessive urination)
2. Polydipsia (i.e., excessive thirst)
3. Polyphagia (i.e., excessive hunger)

These three symptoms are closely related to the hyperglycemia and glycosuria of diabetes.

The exact cause of type 1 diabetes is unknown. Usually, the body's own immune system — which normally fights harmful bacteria and viruses — destroys the insulin-producing (islet) cells in the pancreas. Other possible causes include:

• Genetics
• Exposure to viruses and other environmental factors

https://www.niddk.nih.gov/health-information/diabetes/overview/symptoms-causes#causes

The main difference between the type 1 and type 2 diabetes is that type 1 diabetes is a genetic condition that often shows up early in life, and type 2 is mainly lifestyle-related and develops over time. With type 1 diabetes, your immune system is attacking and destroying the insulin-producing cells in your pancreas.

Type 2 DM is heterogeneous condition ^[1] that describes the presence of hyperglycemia in association with relative insulin deficiency. 

[1] heterogeneous condition is a medical condition with several etiologies (caused by different sets of events).

In Type 2 DM there is no autoimunne destruction of the beta cells. 

Type 2 diabetes—the most common form of diabetes—is caused by several factors, including lifestyle factors and genes.

The main causes are:

1. Overweight, obesity, and physical inactivity. Extra weight sometimes causes insulin resistance and is common in people with type 2 diabetes.

2. Genes and family history. 

3. Hormonal diseases. Some hormonal diseases cause the body to produce too much of certain hormones, which sometimes cause insulin resistance and diabetes.

   • Cushing’s syndrome occurs when the body produces too much cortisol—often called the “stress hormone.”
   • Acromegaly occurs when the body produces too much growth hormone.
   • Hyperthyroidism occurs when the thyroid gland produces too much thyroid hormone.

4. Damage to or removal of the pancreas. Pancreatitis, pancreatic cancer, and trauma can all harm the beta cells or make them less able to produce insulin, resulting in diabetes. If the damaged pancreas is removed, diabetes will occur due to the loss of the beta cells.

https://www.niddk.nih.gov/health-information/diabetes/overview/symptoms-causes#causes

Insulin resistance - It's condition in which muscle, liver, and fat cells do not use insulin well. As a result, your body needs more insulin to help glucose enter cells. At first, the pancreas makes more insulin to keep up with the added demand. Over time, the pancreas can’t make enough insulin, and blood glucose levels rise.

• Glycated hemoglobin (A1C) test. 
  • This test shows average blood sugar level for the past 2 to 3 months. It measures the percentage of blood sugar attached to hemoglobin, the oxygen-carrying protein in red blood cells. 
  • The higher your blood sugar levels, the more hemoglobin you'll have with sugar attached. 
  • A1C level ≥6.5%  on two separate tests means that you have diabetes. 
  • 5.7% ≤ A1C ≤6.4% — prediabetes.
  •  A1C ≤ 5.7% —normal.
• Random blood sugar test.
  • A blood sample will be taken at a random time
  • Blood sugar level of 200 milligrams per deciliter (mg/dL) — 11.1 millimoles per liter (mmol/L) — or higher suggests diabetes.
• Fasting blood sugar test.
  • A blood sample will be taken after you haven't eaten anything the night before (fast).
  • ≤100 mg/dL (5.6 mmol/L) — normal; 
  • 100≤ BG ≤125 mg/dL (5.6 to 6.9 mmol/L) —prediabetes. 
  • 126 mg/dL (7 mmol/L) ≤ on two separate tests — diabetes.
• Oral glucose tolerance test.
  • Fasting overnight after which Blood sugar level is measured. 
  • Then person drink a sugary liquid, and blood sugar levels are tested regularly for the next two hours.
  • ≤140 mg/dL (7.8 mmol/L) — normal.
  • ≥200 mg/dL (11.1 mmol/L) after two hours — diabetes
  • 140≤ BG ≤199 mg/dL (7.8 mmol/L≤ BG ≤11.0 mmol/L) — prediabetes.

https://www.mayoclinic.org/diseases-conditions/diabetes/diagnosis-treatment/drc-20371451#:~:text=Fasting%20blood%20sugar%20test.&text=A%20fasting%20blood%20sugar%20level,separate%20tests%2C%20you%20have%20diabetes.