Cystic Fibrosis (CF)


Cystic fibrosis is a progressive, inherited, rare disease in which CF transmembrane conductance regulator (CFTR) gene mutations produce abnormal CFTR protein channels that negatively affect the transportation of sodium and chloride ions across cellular epithelial membranes. This results in the accumulation of thick, sticky mucus, which causes progressive dysfunction in multiple organ systems.1 Given that the disease is genetic in nature, cystic fibrosis epidemiology is specific to a wide range of factors, as indicated below.

Incidence

The incidence of CF in the United States is estimated at 1000 new cases annually, with similar rates found in the United Kingdom and Canada. Throughout the European Union, 1 in every 2000 to 3000 infants are diagnosed with CF.1

According to researchers, many countries demonstrate evidence of decreasing incidence of CF due to the implementation of newborn screening.2-6 

In Latin and South America, incidence reporting is difficult due to a lack of registries and newborn screening programs; however, the average incidence in these countries is calculated at around 1 in every 8000 individuals, ranging from 1 in 6100 in Argentina to 1 in 15,000 in Costa Rica.2,7 

In Asia, the incidence remains underestimated; however, Middle Eastern countries exhibit a higher incidence than East Asia. In Jordan, researchers report an incidence of 1 in 2560.2,8 In Japan, the incidence of CF is around 1 in every 350,000 births,2,9 while in India, incidence varies from 1 in 10,000 to 1 in 100,000 people.2,10 

Prevalence

With advancing medical technology and treatments, individuals with CF are living longer. Based on registry data from 2016 in the United States, the estimated median survival age is 47 years, with many individuals surviving into their fifth or sixth decades.1 

These medical advancements have gradually increased the prevalence of the disease in the United States, as well as globally. Approximately 30,000 individuals in the United States have CF, while around 70,000 individuals are estimated to have CF globally.1 

Prevalence varies from country to country, with a presumed underdiagnosis in African and Asian countries.1 The highest prevalence of CF is found in Europe, North America, and Australia.11 Patients with CF in developing countries have lower survival rates, with many dying in their teens.1 

Race

In the United States, 1 in every 2500 to 3500 white neonates are diagnosed with CF annually. Significantly lower incidence occurs among other ethnicities, with 1 in 17,000 black neonates and 1 in 31,000 Asian American neonates receiving a CF diagnosis.12

Sex

While CF affects both male and female individuals equally, female patients with CF demonstrate a shorter life expectancy than their male counterparts, typically due to an earlier onset of respiratory infections.13,14 This difference in sex is particularly present in female individuals diagnosed in childhood. Compared with male patients, female patients diagnosed in childhood are less likely to survive past 40 years of age, leading to disparities in age-related CF prevalence.15

Age

Due to the implementation of newborn screening, more than 75% of CF diagnoses in the United States occur before a child reaches 2 years of age.1 Age at diagnosis impacts disease outcomes, with earlier diagnoses resulting in improved survival rates. Nearly 90% of individuals with CF over the age of 40 years obtained diagnoses before they were 10 years of age.15

References

  1. Cystic fibrosis statistics. Cystic Fibrosis News Today. Accessed January 19, 2022.
  2. Scotet V, L’Hostis C, Férec C. The changing epidemiology of cystic fibrosis: incidence, survival and impact of the CFTR gene discovery. Genes (Basel). 2020;11(6):589. doi:10.3390/genes11060589
  3. Scotet V, Duguépéroux I, Saliou P, et al. Evidence for decline in the incidence of cystic fibrosis: a 35-year observational study in Brittany, France. Orphanet J Rare Dis. 2012;7:14. doi:10.1186/1750-1172-7-14
  4. Castellani C, Picci L, Tridello G, et al.; Veneto CF Lab Network. Cystic fibrosis carrier screening effects on birth prevalence and newborn screening. Genet Med. 2016;18(2):145-151. doi:10.1038/gim.2015.68
  5. Hale JE, Parad RB, Comeau AM. Newborn screening showing decreasing incidence of cystic fibrosis. N Engl J Med. 2008;358(9):973-974. doi:10.1056/NEJMc0707530
  6. Castellani C, Picci L, Tamanini A, Girardi P, Rizzotti P, Assael BM. Association between carrier screening and incidence of cystic fibrosis. JAMA. 2009;302(23):2573-2579. doi:10.1001/jama.2009.1758
  7. Scotet V, Gutierrez H, Farrell PM. Newborn screening for CF across the globe—where is it worthwhile? Int J Neonatal Screen. 2020;6(1):18. doi:10.3390/ijns6010018
  8. Nazer HM. Early diagnosis of cystic fibrosis in Jordanian children. J Trop Pediatr. 1992;38(3):113-115. doi:10.1093/tropej/38.3.113
  9. Yamashiro Y, Shimizu T, Oguchi S, Shioya T, Nagata S, Ohtsuka Y. The estimated incidence of cystic fibrosis in Japan. J Pediatr Gastroenterol Nutr. 1997;24(5):544-547. doi:10.1097/00005176-199705000-00010
  10. Kapoor V, Shastri SS, Kabra M, et al. Carrier frequency of F508del mutation of cystic fibrosis in Indian population. J Cyst Fibros. 2006;5(1):43-46. doi:10.1016/j.jcf.2005.10.002
  11. Elborn JS. Cystic fibrosis. Lancet. 2016;388(10059):2519-2531. doi:10.1016/S0140-6736(16)00576-6
  12. Cystic fibrosis: frequency. MedlinePlus. Updated July 6, 2021. Accessed January 19, 2022. 
  13. Cystic fibrosis symptoms and treatment. Children’s Hospital of Pittsburgh. Accessed January 19, 2022.
  14. Harness-Brumley CL, Elliott AC, Rosenbluth DB, Raghavan D, Jain R. Gender differences in outcomes of patients with cystic fibrosis. J Womens Health (Larchmt). 2014;23(12):1012-1020. doi:10.1089/jwh.2014.4985
  15. Nick JA, Chacon CS, Brayshaw SJ, et al. Effects of gender and age at diagnosis on disease progression in long-term survivors of cystic fibrosis. Am J Respir Crit Care Med. 2010;182(5):614-626. doi:10.1164/rccm.201001-0092OC

Reviewed by Kyle Habet, MD, on 1/25/2022.

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