Cystic fibrosis (CF) is a heritable disease caused by mutations in a gene called CFTR, which encodes for a transport protein that controls the movement of salts in and out of cells. Mutations in the CFTR gene lead to the transport protein to be made incorrectly or not at all, causing salts not to be trafficked normally at the cell membrane. This leads to a buildup of thick mucus in various organs and tissues.

While the most devastating symptoms of CF are centered in the lungs, nearly half of all CF patients also develop diabetes as a result of the disease.

What is diabetes?

Diabetes occurs when blood glucose levels (also called blood sugar) are too high. There can be different causes of this. Type 1 diabetes is normally caused by the immune system mistakenly attacking the cells in the pancreas that secrete insulin, the hormone that lowers blood sugar. Type 2 diabetes is caused by the body failing to make or use insulin well. This can be caused by problems in the pancreas in secreting insulin, or in other tissues in failing to respond to insulin appropriately.

What is CF-related diabetes (CFRD)?

CFRD shares some traits with both type 1 and type 2 diabetes. The sticky, thick mucus seen in CF damages the pancreas, leading to insufficient insulin production, much like in type 1 diabetes. The pancreas continues to produce insulin, but not enough to stay healthy. Likewise, people with CF do not have a normal response to insulin (a hallmark of type 2 diabetes), a condition known as being “insulin resistant.” Insulin resistance can be especially evident during an illness or when using steroid medications.

How is CFRD diagnosed?

Most CFRD patients do not know they are diabetic until the disease is diagnosed. For this reason, CF care guidelines for CFRD recommend that people with CF age 10 and older undergo an oral glucose tolerance test every year.

CFRD symptoms include increased thirst and urination, excessive fatigue, weight loss, and an unexplained decline in lung function. However, unlike people with type 1 and 2 diabetes, those with CFRD need to keep to a high-calorie diet to maintain a healthy body weight.

How is CFRD treated?

CFRD treatment includes monitoring blood-sugar levels and keeping these levels within the normal range, usually with insulin, maintaining an active lifestyle (150 minutes of moderate aerobic exercise per week is recommended), and eating healthy foods.

There are different types of insulin, classified by how long they last in the body and how fast they work. Insulin improves nutrient absorption in order to maintain a healthy body weight and nutritional status.

Oral hypoglycemics, or anti-diabetic therapies, may be used if patients have difficulty taking insulin.

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Cystic Fibrosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

Emily holds a Ph.D. in Biochemistry from the University of Iowa in 2018 and is currently a postdoctoral scholar at the University of Wisconsin-Madison. She graduated with a Masters in Chemistry from the Georgia Institute of Technology and a Bachelors in Biology and Chemistry from the University of Central Arkansas. Emily is passionate about science communication, and, in her free time, writes and illustrates children’s stories.
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Emily holds a Ph.D. in Biochemistry from the University of Iowa in 2018 and is currently a postdoctoral scholar at the University of Wisconsin-Madison. She graduated with a Masters in Chemistry from the Georgia Institute of Technology and a Bachelors in Biology and Chemistry from the University of Central Arkansas. Emily is passionate about science communication, and, in her free time, writes and illustrates children’s stories.