Diabetes mellitus is a metabolic disorder that occurs when the body either produces insufficient or no insulin or doesn’t use insulin properly causing blood sugar (glucose) levels to rise (hyperglycemia).
Glucose is the body’s main source of energy, and the pancreas produces a hormone called insulin that helps convert glucose from the food you eat into energy the body uses.
There are three main types of diabetes:
- Type 1 diabetes (previously called insulin-dependent or juvenile diabetes)
- Little to no insulin is produced by the pancreas
- There is no cure for type 1 diabetes
- In type 1 diabetes, the immune system mistakenly attacks and destroys the bets cells in the pancreas that produce insulin
- It is an autoimmune condition, which means it is chronic and will need to be managed for the rest of your life
- Currently, type 1 diabetes is not curable because a treatment would need to instruct the immune system to stop attacking the beta cells, or to provide another source of beta cells the immune system is unable to attack – this is difficult to do
- Some studies have cured type 1 diabetes in animals, but these results have not translated to humans
- To date, studies for a cure for type 1 diabetes in humans have failed in terms of effectiveness and safety
- Type 2 diabetes
- The body doesn’t use insulin properly causing blood sugar levels to rise
- The most common form of diabetes
- Type 2 diabetes may be reversed in some cases with proper diet, exercise, staying a healthy weight, and lifestyle changes
- These changes must be maintained for life or the disease can return
- Gestational diabetes
- Disrupts the way the body uses sugar (glucose) during pregnancy
- Occurs because pregnancy increases the body's need for insulin, but the body cannot always make enough
- After delivery, gestational diabetes usually goes away and a woman’s blood sugar levels return to normal
What Are Symptoms of Diabetes?
Symptoms of all types of diabetes include:
- Increased urination
- Increased thirst
- Increased hunger
- Blurry vision
- Fatigue
- Wounds that do not heal
- Frequent infections
- Darkened skin, often in the armpits and neck
- Numbness, tingling, or pain in the feet or hands (more common in type 2)
- Unexplained weight loss (more common in type 1)
What Causes Diabetes?
Type 1 diabetes is thought to be caused by an autoimmune reaction in which the body mistakenly attacks and destroys the beta cells in the pancreas that make insulin.
Risk factors for developing type 1 diabetes include:
- Genetics/family history
- Age: more likely to occur in children, teens, and young adults, though it can develop at any age
- Ethnicity: Caucasians are more likely to develop type 1 diabetes than African Americans and Hispanic/Latino Americans
- Certain triggers, such as viruses
Type 1 diabetes is not caused by diet or lifestyle factors.
Type 2 diabetes is caused by several factors, including:
- Genetics
- Family history
- Occurs more often in certain ethnic groups: African Americans, Alaskan Natives, American Indians, Asian Americans, Hispanic/Latinos, Native Hawaiians, or Pacific Islanders
- Lifestyle factors
- Overweight or obesity
- Physical inactivity
Factors that can increase the risk of developing type 2 diabetes include:
- Age over 45 years
- Depression
- Giving birth to a baby weighing 9 pounds or more
- High blood pressure
- History of gestational diabetes
- History of heart disease or stroke
- Low HDL (“good”) cholesterol or high triglycerides
- Polycystic ovary syndrome (PCOS)
The cause of gestational diabetes is not known, and it can be difficult to predict which women will develop the condition when they become pregnant.
Risk factors for developing gestational diabetes include:
- Age over 25 years
- Overweight/obesity
- Ethnicity: Hispanic-Americans, African-Americans, Native Americans, South or East Asians, or Pacific Islanders
- Family history of diabetes
- Prior gestational diabetes during pregnancy
How Is Diabetes Diagnosed?
Diabetes is diagnosed with the following tests:
- Fasting plasma glucose (FPG) test
- A1C test
- Glucose challenge test
- Random plasma glucose (RPG) test
- Oral glucose tolerance test (OGTT)
What Is the Treatment for Diabetes?
Diabetes is treated with lifestyle modifications and medications when needed.
Lifestyle changes to manage diabetes include:
- Manage A1C (average blood glucose level over the past 3 months)
- Check blood glucose levels daily
- Keep blood pressure in check
- Maintain healthy cholesterol levels
- Don’t smoke
- Follow a diabetes meal plan as recommended by your doctor or nutritionist
- Exercise regularly
- Get adequate sleep
- Manage stress/practice relaxation techniques
- Take prescribed diabetes medications
Medications used to treat diabetes include:
- Insulin
- Meglitinides
- Alpha-glucosidase inhibitors
- Thiazolidinediones
- DPP- 4 Inhibitors
- Sulfonylureas
- Biguanides
- Dopamine receptor agonists
- Bile acid sequestrants
- SGLT2 inhibitors
- GLP-1 receptor agonists
- Amylin analog
- Combination medicines, which may be made up of more than one medication in the above classes
- Women with gestational diabetes may need insulin or metformin
If lifestyle changes and medications are insufficient, other treatments for diabetes may include:
- Weight-loss surgery (bariatric surgery) for some patients who are obese
- Artificial pancreas
From 
https://www.fda.gov/media/119148/download
https://www.cdc.gov/diabetes/basics/type1.html
https://www.uptodate.com/contents/gestational-diabetes-beyond-the-basics?search=Gestational%20Diabetes%5C&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2
https://diabetesstrong.com/cure-for-type-1-diabetes/