Cystic fibrosis affects roughly 40,000 people in the United States and an estimated 162,000 people across 94 countries worldwide. That makes it one of the most common life-shortening genetic conditions, though its frequency varies dramatically depending on ancestry and geography.
Incidence by Ancestry
CF occurs most frequently in people of European descent, where it affects an estimated 44 to 52 out of every 100,000 births. But it is far from exclusive to white populations. A 2026 analysis of global genetic data published in The Lancet found CF affects 11 to 14 per 100,000 births in African and African American populations, 7 per 100,000 in admixed American (largely Latin American) populations, 6 per 100,000 in South Asian populations, and 4 per 100,000 in East Asian populations.
Those numbers matter more than they might seem at first glance. Because countries like India and Brazil have far higher birth rates than the U.S. or U.K., the actual number of babies born with CF each year in those countries is comparable. India alone is estimated to have 1,400 to 1,600 CF births per year, compared to about 1,000 in the U.S. and 300 in the U.K. The disease is genuinely global, even though it has historically been studied and diagnosed primarily in white populations.
How Many People Carry the Gene
CF is a recessive genetic condition, meaning a child must inherit a faulty copy of the CFTR gene from both parents to develop the disease. People who carry just one faulty copy are called carriers. They don’t have CF symptoms themselves, but they can pass the gene to their children.
About 1 in 30 Americans of European or Ashkenazi Jewish descent carries a CF mutation. Across all ethnicities combined, the carrier frequency is roughly 1 in 38. When two carriers have a child together, there’s a 25% chance that child will have CF, a 50% chance the child will be a carrier, and a 25% chance the child will inherit neither copy of the mutation.
CF in the United States
The Cystic Fibrosis Foundation’s 2024 Patient Registry tracked 33,989 people with CF across the country. The registry captures more than 80% of the known U.S. CF population, with roughly 1,000 new cases diagnosed each year.
The demographic profile of CF in the U.S. is shifting. More than 15% of people in the 2024 registry identify as a person of color: 10.3% Hispanic, 3.4% Black or African American, 2.2% multiracial, and 0.6% Asian. The Foundation notes that cases among people of color are likely underreported, partly because clinicians have historically been less likely to suspect CF in non-white patients.
A Growing Adult Population
CF was once considered a childhood disease. Most children diagnosed in the mid-20th century did not survive to adulthood. That has changed dramatically. Based on 2024 registry data, the median predicted survival age for someone born with CF between 2020 and 2024 is 65 years. This reflects major advances in treatment, particularly newer therapies that target the underlying protein defect rather than just managing symptoms.
As a result, adults now make up a large and growing share of the CF population. This shift has reshaped how the disease is managed, with increasing focus on complications that emerge in adulthood, including CF-related diabetes, liver disease, bone thinning, and fertility challenges.
Underdiagnosis Around the World
The global estimate of 162,000 people living with CF almost certainly undercounts the true number. In many countries, newborn screening for CF doesn’t exist, genetic testing is limited, and the disease can go unrecognized for years or be misdiagnosed as asthma, chronic bronchitis, or tuberculosis.
South Asia illustrates the gap well. Genetic analysis suggests CF occurs in roughly 1 in 13,000 people in South Asian populations, a rate that would translate to tens of thousands of undiagnosed cases across a region of nearly 2 billion people. In much of Africa and Latin America, the situation is similar: the genetic mutations are present, but the diagnostic infrastructure to catch them often isn’t.
How CF Is Diagnosed
In the U.S. and many other high-income countries, CF is typically caught through newborn screening. A blood test taken in the first few days of life flags elevated levels of a pancreatic enzyme, which triggers further evaluation. The confirmatory step is a sweat test, which measures the concentration of chloride in sweat. People with CF have saltier sweat because the defective protein that causes the disease also regulates salt transport across cell surfaces.
A chloride level of 60 millimoles per liter or higher points strongly toward CF. Levels between 30 and 59 fall into an intermediate zone that requires additional genetic testing to clarify. A level below 29 is considered normal. In some cases, particularly when symptoms appear later in life or in populations where CF is less expected, genetic testing is used as a primary diagnostic tool to identify specific mutations in the CFTR gene.
Not everyone with CF is diagnosed as a newborn. Some people with milder mutations don’t develop obvious symptoms until adolescence or adulthood, and they may go years with chronic sinus infections, unexplained digestive problems, or male infertility before CF is considered.