What Causes Diabetes?

Diabetes is a metabolic disorder that occurs when blood sugar (glucose) is too high (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 your body uses. When the body doesn’t make enough insulin or doesn’t produce any at all, or your body becomes resistant to insulin, glucose doesn’t reach the cells to be used for energy. This results in diabetes. 

Types of diabetes include:

• Type 1 diabetes (formerly called juvenile diabetes) is an autoimmune condition in which the body does not produce insulin because the body’s immune system attacks and destroys the cells in the pancreas that make insulin. Type 1 diabetes is treated by using insulin. 
• Type 2 diabetes, the most common form of diabetes, is a condition in which the body does not produce adequate insulin or does not use it efficiently. Type 2 diabetes can occur at any age, but often occurs in middle-aged and older adults. There are multiple types of medications used to treat type 2 diabetes.
• Gestational diabetes develops in some women during pregnancy and usually goes away after the baby is born. Gestational diabetes can increase a woman’s risk of developing type 2 diabetes later in life. 
• Less common types of diabetes include monogenic diabetes, which is an inherited form of diabetes, and cystic fibrosis-related diabetes.

Symptoms of type 1 diabetes often begin quickly, within in a matter of weeks, while symptoms of type 2 diabetes usually develop slowly over several years. People who have type 2 diabetes may have no symptoms or only mild symptoms. 

Symptoms of diabetes include:

• Increased thirst 
• Increased urination
• Increased hunger
• Fatigue
• Blurred vision
• Numbness or tingling in the feet or hands
• Sores that do not heal
• Unexplained weight loss

The causes of diabetes differ depending on the type. 

Type 1 diabetes occurs when the body's immune system mistakenly attacks and destroys the insulin-producing cells in the pancreas. The cause of type 1 diabetes is unknown, but it is believed to be caused by genes and environmental factors, such as viruses, that might trigger the disease. 

Type 2 diabetes is caused by several factors, including: 

• Genetics/family history
• Lifestyle factors 
• Being overweight or obese
• Physical inactivity

Gestational diabetes is believed to be cause by hormonal changes that occur during pregnancy along with genetic and lifestyle factors such as being overweight or obese. A family history may play a role. 

Other causes of diabetes include:

• Genetic mutations
• Other diseases
  • Cystic fibrosis
  • Hemochromatosis 
  • Cushing’s syndrome
  • Acromegaly
  • Hyperthyroidism
• Damage to or removal of the pancreas 
  • Pancreatitis
  • Pancreatic cancer
  • Trauma to the pancreas
• Certain medicines 
  • Niacin (vitamin B3)
  • Diuretics (water pills)
  • Anti-seizure drugs
  • Psychiatric drugs
  • Human immunodeficiency virus (HIV) medications
  • Pentamidine, a drug used to treat pneumonia 
  • Glucocorticoids
  • Medicines used to prevent organ transplant rejection

Diabetes is diagnosed with the following tests: 

• Fasting plasma glucose (FPG) test 
• A1C test 
• Random plasma glucose (RPG) test 
• Glucose challenge test
• Oral glucose tolerance test (OGTT)

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
  • Eat plenty of fruits and vegetables, whole grains, beans, lean poultry and fish, and low-fat dairy
  • Drink water
  • Chose foods that are low-calorie, low-fat, low-sugar, and low-salt
• Exercise regularly 
• Take prescribed diabetes medications 

Medications used to treat diabetes include: 

• People with type 1 diabetes need insulin
• People with type 2 diabetes may need insulin, or other diabetes medications 
  • Meglitinides such as repaglinide (Prandin) and nateglinide (Starlix)
  • Alpha-glucosidase inhibitors such as miglitol (Glyset) and acarbose (Precose)
  • Thiazolidinediones such as pioglitazone (Actos) and rosiglitazone (Avandia)
  • DPP- 4 Inhibitors such as sitagliptin (Januvia), saxagliptin (Onglyza), alogliptin (Nesina), and linagliptin (Tradjenta)
  • Sulfonylureas such as glimepiride (Amaryl), glyburide (Diabeta,  Glynase), chlorpropamide (Diabinese), glipizide (Glucotrol, Glucotrol XL), tolbutamide, and tolazamide
  • Biguanides such as metformin (Fortamet, Glucophage, Glucophage XR, Glumetza, and Riomet)
  • Dopamine receptor agonists such as bromocriptine (cycloset)
  • Bile acid sequestrants such as colesevelam (Welchol)
  • SGLT2 inhibitors such as dapagliflozin (Farxiga), canagliflozin (Invokana), empagliflozin (Jardiance), and ertugliflozin (Steglatro)
  • GLP-1 receptor agonists such as lixisenatide (Adlyxin), exenatide (Bydureon, Byetta), semaglutide (Ozempic), albiglutide (Tanzeum), dulaglutide (Trulicity), and liraglutide (Victoza)
  • Amylin analog such as pramlintide acetate (Symlin)
  • Combination medicines, which may be made up of more than one medication in the above classes
• People 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 certain patients who are obese
• Artificial pancreas 
• Pancreatic islet transplantation (treatment is experimental and for poorly controlled type 1 diabetes)

If blood sugar levels are not well-managed, complications of diabetes can include:

• Low blood glucose (hypoglycemia) 
• Heart disease
• Stroke
• Diabetic neuropathy
• Kidney disease
• Eye disease
• Foot problems
• Gum disease and other dental problems
• Sexual and bladder problems