Changing patterns in the epidemiology of β-thalassemia

Abstract

β-thalassemia major is an inherited hemoglobinopathy that requires lifelong red blood cell transfusions and iron chelation therapy to prevent complications due to iron overload. Traditionally, β-thalassemia has been more common in certain regions of the world such as the Mediterranean, Middle East, and Southeast Asia. However, the prevalence of β-thalassemia is increasing in other regions, including Northern Europe and North America, primarily due to migration. This review summarizes the available data on the changing incidence and prevalence of β-thalassemia as well as factors influencing disease frequency. The data suggest that the epidemiology of β-thalassemia is changing: Migration has increased the prevalence of the disease in regions traditionally believed to have a low prevalence, while, at the same time, prevention and screening programs in endemic regions have reduced the number of affected individuals. Various approaches to prevention and screening have been used. Region-specific prevention and treatment programs, customized to align with local healthcare resources and cultural values, have been effective in identifying patients and carriers and providing information and care. Significant challenges remain in universally implementing these programs.

Keywords: beta-thalassemia major; epidemiology; incidence.

Figure 1

β‐thalassemia registries^†. 1. Thalassemia Clinical Research Network ⁹⁴ , ⁹⁵ —Canada, USA. 2. Thalassemia Data Collection and Blood Safety Monitoring—USA. 3. Registry and Surveillance System for Hemoglobinopathies ⁹³ —USA. 4. Thalassemia Clinical Research Network Longitudinal Cohort Study ⁹⁵ —Canada, UK, USA. 5. ITHANET ⁹² —59 countries. 6. National Haemoglobinopathy Registry ⁴⁶ —UK. 7. United Kingdom Thalassaemia Register ⁵ , ⁴⁴ and United Kingdom Register for Prenatal Diagnosis for Haemoglobin Disorders ⁴⁴ , ⁹⁷ —UK. 8. French Certified Registry of Patients Affected by Thalassemia ⁷ , ⁹⁸ —France. 9. National Registry of Hemoglobinopathies ⁹⁹ —Spain. 10. The Italian Registry for Thalassemia and Hemoglobinopathies—National Institute of Health–Italy. 11. Finnish Hematology Registry and Clinical Biobank–Finland. 12. National Registry of Patients with Beta‐Thalassemia Major ³⁶ –Bulgaria. 13. National Registry for Hemoglobinopathies in Greece ⁸ , ³⁸ –Greece. 14. National Haemoglobinopathy Registry ¹⁰⁰ —Turkey. 15. Electronic Thalassemia Registry Mazandaran ¹⁰¹ —Iran. 16. Unnamed ¹¹ —Oman. 17. ThalRThai (V. Viprakasit, personal communication)—Thailand. ^† Only includes registries that offer at least partial information and/or publications in English; known numbers of patients with beta‐thalassemia are shown as per publication date or August 2020, whichever came first