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Secondary diabetes is diabetes that results from (is secondary to) other diseases and conditions. Many primary conditions can contribute to secondary diabetes, including:

• Other endocrine disorders. Examples include hyperthyroidism, conditions involving overactive adrenal glands such as Cushing’s syndrome, and conditions involving excessive levels of growth hormones such as acromegaly.
  
  
• Pancreatic disorders. Conditions that disrupt pancreas function and may lead to secondary diabetes include pancreatitis, excessive absorption of iron (hemochromatosis), physical trauma to the pancreas and pancreatic damage due to malnutrition.
  
  
• Some liver diseases. These include fatty liver disease and hepatitis C.
  
  
• Celiac disease (gluten intolerance). This and other autoimmune diseases increase the risk of autoimmune diabetes.
  
  
• Some cancers. Carcinoid tumors in the lungs, stomach or intestines can cause secondary diabetes by producing a hormone (ACTH) that causes the adrenal glands to overproduce cortisol. Adrenal and pituitary tumors can have this same effect. Pancreatic cancer can impair pancreas function.
  
  
• Drugs, chemical agents and toxins. Substances in the body can disrupt the normal function of the endocrine system and hormones it produces, and cause secondary diabetes. These may include:
  
• • Two classes of antihypertensives (drugs for elevated blood pressure): diuretics and beta blockers

In addition, some studies have linked common consumer plastics and plastics ingredients including phthalates and bisphenol A to insulin resistance. Other chemicals including the defoliant Agent Orange, dioxin (its active ingredient) and certain pesticides have also been linked.

• Other medical treatments including:
  
• • Pancreatectomy. Removal of the pancreas, for conditions such as pancreatic cancer, other severe pancreatic disease or a form of hyperinsulinemia in babies called persistent hyperinsulinemic hypoglycemia of infancy (PHHI). Total pancreatectomy causes diabetes, and a partial pancreatectomy may, depending on how many of the beta cells are removed.

• • Orchiectomy. Surgical removal of the testicles. Orchiectomy may be necessary to treat testicular cancer. It can also be, like hormonal drug therapy, a form of androgen deprivation therapy for prostate cancer. Recent studies indicate that androgen deprivation therapy and low levels of testosterone (male hypogonadism) may increase men’s risk of diabetes.
    
    
  • Radiation therapy. This cancer treatment can cause hyperglycemia and increase the risk of diabetes.
    
    
• Genetic conditions. Genetic defects can lead to a host of conditions that can disrupt the body’s normal use of insulin and glucose. Cystic fibrosis often causes cystic fibrosis-related diabetes (CFRD), which has some characteristics of type 1 diabetes and some characteristics of type 2. Other inherited conditions that can cause secondary diabetes include:
  
• • Neuromuscular disorders such as Huntington’s disease and some forms of muscular dystrophy
    
    
  • Insulin resistance syndromes such as ataxia-telangiectasia and leprechaunism
    
    
  • Chromosomal disorders such as Down syndrome, Klinefelter syndrome and Turner syndrome

There are many ways that secondary diabetes can develop. Examples include:

• Damage to or destruction of beta cells. Beta cells are the parts of the pancreas that produce and secrete insulin. The body’s cells cannot use glucose without insulin. The beta cells can be removed in a pancreatectomy, or destroyed or inhibited by diseases, chemicals or radiation. Beta cells may also function improperly due to genetic defects.
  
  
• Damage to the islets of Langerhans. The endocrine portions of the pancreas, which include alpha cells, beta cells and delta cells. They may be damaged by limited blood flow due to inflammation of the pancreas.
  
  
• Production of abnormal insulin or insulin receptors. Some genetic defects cause the beta cells to produce insulin molecules that are not recognized by body’s cells, preventing glucose transportation. Mutations can also cause cells to not recognize typical insulin.