Understanding Cystic Fibrosis Worldwide

Cystic fibrosis is found throughout the world, though its frequency varies considerably depending on where you live. Nearly 40,000 children and adults in the United States are currently living with cystic fibrosis, and more than 100,000 people worldwide have the condition^[2]. This makes it one of the more common genetic diseases, though it is still considered relatively rare overall.

When we look at life expectancy for people born with cystic fibrosis, the picture has improved dramatically over recent decades. Children born between 2019 and 2023 who have cystic fibrosis are expected to live an average of 61 years. On average, half of babies born in 2023 with cystic fibrosis are expected to reach the age of 68 or older^[2]. This is a remarkable change from the past, when cystic fibrosis used to cause death in childhood^[2]. Many people with cystic fibrosis now live into their late 30s, and many even into their 50s or longer, with some patients now able to live into their 70s^[11].

The condition affects people of all backgrounds, though the specific mutation (a change in a gene) that a person inherits can influence how severe their symptoms will be. Over 50% of individuals living with cystic fibrosis are adults, highlighting the need for specialized care as their health needs evolve^[17].

What Causes Cystic Fibrosis

Cystic fibrosis is caused by changes to a specific gene called the CFTR gene. This gene normally makes a protein that works as a kind of gate on the surface of cells, allowing certain minerals to pass through. Specifically, CFTR creates gates for chloride ions (a type of mineral with a negative electrical charge). When chloride moves out of the cell, it takes water with it, which thins out the mucus in your body and makes it slippery and easy to move^[3].

In people with cystic fibrosis, mutations in the CFTR gene prevent this process from working correctly. The faulty protein affects the body’s cells, tissues, and the glands that make mucus and sweat^[2]. Normal mucus is slippery and protects the airways, digestive tract, and other organs and tissues. Cystic fibrosis causes mucus to become thick and sticky^[2]. Because the minerals that move water into mucus get trapped inside cells, the mucus stays thick and sticky rather than thin and watery^[3].

There are actually over 2,000 possible mutations in the CFTR gene, each disrupting chloride transport in different ways. Some mutations produce no proteins at all, some produce only small amounts of proteins, and some produce proteins that simply do not work properly^[6]. These mutations are grouped into different categories (classes I to VI) depending on the effect they have on the protein^[3].

How Cystic Fibrosis is Inherited

Cystic fibrosis is an inherited genetic condition, which means it is passed down from parents to their children. A child needs to inherit one copy of the mutated gene from each parent to develop cystic fibrosis. If they only inherit one copy from one parent, they will not develop the disease. However, they will be a carrier of that mutated gene^[1].

If two carriers have a baby together, there is a one in four (25%) chance their child will have cystic fibrosis, a two in four (50%) chance their child will not get cystic fibrosis but will be a carrier, and a one in four (25%) chance their child will not get cystic fibrosis or be a carrier^[12]. This inheritance pattern is called autosomal recessive, and it explains why cystic fibrosis can appear in families even when neither parent has the disease.

Being a carrier is actually quite common. In the United States, one in 20 people are carriers of the cystic fibrosis gene mutation^[7]. Carriers typically have no symptoms themselves, but they can pass the gene to their children. If a relative has cystic fibrosis or is a known carrier, you can arrange to be tested yourself for the gene through carrier testing^[12].

Recognizing the Symptoms

The symptoms of cystic fibrosis can vary widely from person to person. Some people have few or no symptoms, while others experience severe symptoms or life-threatening complications^[2]. Cystic fibrosis is usually diagnosed shortly after birth as part of newborn screening programs, but if the condition goes undiagnosed, symptoms may only become noticeable when a child is a teenager^[12].

Common symptoms affecting the lungs and airways include a cough that does not go away and brings up mucus, wheezing and shortness of breath, and frequent sinus infections and chest infections^[12]. People with cystic fibrosis often experience frequent lung infections, such as recurrent pneumonia or bronchitis, because the thick mucus in their airways creates an environment where germs thrive^[3]. Sometimes lung problems will suddenly worsen in what is called a flare-up or exacerbation^[2].

Symptoms affecting the digestive system are also common. The thick mucus can block ducts that release digestive enzymes (proteins that help break down food), making it hard to get nutrients from the digestive tract. This leads to symptoms such as constipation, stomach pain, bloating and swelling, and large, greasy and sticky stools that are hard to flush away^[12]. Many children with cystic fibrosis experience slow growth or failure to thrive, which means an inability to gain weight despite having a good appetite and taking in enough calories^[3].

Cystic fibrosis can affect other parts of the body and cause additional symptoms. These include swollen fingertips and rounder nails, very salty sweat that can leave small crystals on the skin, and in adults, losing weight without trying to^[3]. There are also two types of cystic fibrosis: classic cystic fibrosis, which often affects multiple organs and is usually diagnosed in the first few years of life, and atypical cystic fibrosis, which is a milder form that may only affect one organ or have symptoms that come and go, and is usually diagnosed in older children or adults^[3].

Ways to Prevent Complications

While cystic fibrosis itself cannot be prevented because it is a genetic condition, there are many steps that people with cystic fibrosis can take to prevent complications and protect their health. Avoiding germs is especially important because lung infections are one of the most serious complications. You need to be on germ patrol at all times, staying at least 6 feet away from anyone who is sick and avoiding activities that put you near other people with cystic fibrosis^[16].

Frequently washing your hands with soap and water, cleaning and disinfecting medical equipment properly, and not sharing items that come into contact with saliva are all essential habits^[16]. People with cystic fibrosis should also avoid contact with dust or dirt and stay current on their vaccines, including the flu vaccine. Getting a flu shot every year in the fall and receiving pneumococcal vaccines as recommended by a healthcare provider can help protect against infections^[15].

Tobacco smoke is especially harmful for people with cystic fibrosis. Those with the condition should not smoke or be exposed to secondhand smoke, as it damages the lungs and makes breathing problems worse^[15].

Regular exercise is recommended as a way to prevent lung complications. Exercise helps clear mucus from the lungs, strengthens breathing muscles, and improves the overall fitness of the lungs and heart^[15]. Working with a cystic fibrosis care team to find an exercise program that works best for you, aiming for about 20 minutes of moderate exercise every day of the week, can make a real difference^[16].

Nutrition is another key area for prevention. People with cystic fibrosis need to eat a well-balanced healthy diet and drink plenty of fluids. Because the condition affects how the body absorbs nutrients, eating enough calories and taking recommended supplements becomes especially important^[15].

How Cystic Fibrosis Changes the Body

Understanding how cystic fibrosis changes the way the body works helps explain why the symptoms occur and why treatment is so important. The disease affects many body parts and systems, with the most serious and common effects coming from mucus buildup in the lungs and airways^[14].

In healthy lungs, thin, slippery mucus protects the airways and helps trap germs and particles that you breathe in. This mucus is then cleared away naturally. In cystic fibrosis, the thick, sticky mucus clogs the lungs, causing breathing problems and making it easy for bacteria to grow. This leads to repeated lung infections and lung damage^[5]. As mucus builds up, it can cause blockages, damage, or infections in affected organs^[2].

Common lung complications include bronchiectasis, which is damage to the airways from infections. Pulmonary exacerbations occur when you have worsening cough, shortness of breath, and more mucus, with tests showing a decline in lung function. These exacerbations are caused by inflammation from bacteria in the airways and lungs^[14]. Another complication is allergic bronchopulmonary aspergillosis, an allergic reaction in the lungs to a fungus. Sometimes the lung can collapse due to air in the space between the lung and chest wall, a condition called pneumothorax^[14].

The pancreas is another organ heavily affected by cystic fibrosis. Mucus can build up and block the pancreas, causing inflammation called pancreatitis. The pancreas makes digestive enzymes that help break down food as well as the hormone insulin^[14]. When the pancreas is damaged, it cannot make the enzymes needed to help digest food properly. This affects how well the body gets nutrients^[16].

Damage to the pancreas from cystic fibrosis can cause malnutrition, including low levels of vitamins and minerals. People with cystic fibrosis may have trouble absorbing fats, which means they may also have difficulty absorbing certain vitamins such as A, D, E, and K, which need fat to be absorbed by the body^[19]. Pancreatic damage can also lead to diabetes, a common complication called cystic fibrosis-related diabetes^[14].

Because the body uses more energy to breathe, fight infections, and maintain weight than in people without cystic fibrosis, those with the condition often need about twice the calories the average person needs in a day^[16]. A high-calorie, high-fat diet, with 40% of total calories from fat, is generally recommended^[19].

Cystic fibrosis can also affect the liver, sinuses, intestines, and sex organs^[3]. The condition causes abnormally salty sweat because the body’s salt and water balance is disrupted^[3]. This is why in medieval Europe, children with salty skin were recognized as having a serious illness, even though the cause was not understood at the time. The curse that became folklore pronounced, “Woe to the child who tastes salty from a kiss on the brow, for he is cursed and soon will die”^[6].