What is Cystic Fibrosis?
Cystic fibrosis, often called CF, is a lifelong inherited condition that mainly affects the lungs and digestive system. It is caused by a faulty gene, which affects the way salt and water move in and out of the body’s cells. This makes mucus in the body thicker and stickier than normal. Over time, this mucus can build up, particularly in the lungs and pancreas, causing breathing difficulties, repeated infections and problems digesting food.
CF is something a person is born with. It cannot be caught from another person. In the UK, more than 11,000 people are living with cystic fibrosis, and around 1 in 25 people carries the faulty gene that can cause it, often without knowing.
For a child to be born with cystic fibrosis, both parents must carry the faulty CF gene. When both parents are carriers, each pregnancy has a 1 in 4 chance of the child having CF, a 1 in 2 chance of the child being a carrier, and a 1 in 4 chance of the child not having the faulty gene.
How CF affects the lungs
One of the main ways cystic fibrosis affects the body is through the lungs. Thick, sticky mucus can build up in the airways, making it harder to breathe and creating an environment where bacteria can grow. This can lead to repeated chest infections, coughing, wheezing and, over time, damage to the lungs.
Many people with CF need daily treatment to help clear mucus from their lungs. This may include physiotherapy, exercise, inhaled medicines and antibiotics to treat or help prevent infections. People with CF are also advised not to meet or come into close contact with each other, because of the risk of cross-infection.
How CF affects digestion
Cystic fibrosis can also affect the digestive system, especially the pancreas. The pancreas normally produces enzymes that help the body digest food and absorb nutrients. In many people with CF, thick mucus blocks the pancreas, stopping these enzymes from reaching the gut properly.
This can make it harder to gain weight and get enough nutrition, even when someone is eating well. Many people with CF take enzyme capsules with meals and snacks to help them digest food. Some people may also need a high-calorie diet, vitamin supplements and support from specialist dietitians.
As people with CF get older, some may develop cystic fibrosis-related diabetes, because of damage to the pancreas. This is monitored as part of regular CF care.
Symptoms of cystic fibrosis
Symptoms can vary from person to person. Some people are diagnosed very early in life, while others may have milder symptoms and be diagnosed later. In the UK, most cases are now picked up through newborn screening using the heel prick test.
Common symptoms can include:
- A persistent or troublesome cough
- Repeated chest infections
- Wheezing or shortness of breath
- Difficulty gaining weight
- Greasy, bulky or frequent stools
- Stomach discomfort or constipation
- Tiredness or reduced energy
These symptoms can also be caused by other conditions, so medical advice should always be sought if there are concerns.
Treatment and outlook
There is currently no cure for cystic fibrosis, but treatment has improved greatly over the years. Care usually involves a specialist CF team and may include physiotherapy, exercise, antibiotics, nutritional support, enzyme capsules and newer medicines called CFTR modulators, which target the underlying fault in certain types of CF.
Thanks to earlier diagnosis, better care and advances in treatment, many people with CF are now living longer than ever before. The latest UK CF Registry report says that, based on 2024 data, half of babies born with CF today are predicted to live to at least 66 years. However, CF remains a serious, complex and life-limiting condition, and not everyone can benefit from every new treatment.
Living with CF
Cystic fibrosis affects far more than a person’s health. It can affect school, work, family life, friendships and emotional wellbeing. Daily treatments can take time and energy, and families often have to manage hospital appointments, medication routines and the uncertainty that comes with a long-term condition.
Awareness, research and support continue to make a real difference. By learning more about cystic fibrosis, we can help people understand the challenges faced by those living with CF and support the work being done to improve lives now and in the future.