β-Thalassemia Has High Rates in Mediterranean, Middle Eastern, and South Asian Populations
β-thalassemia is the predominant thalassemia type with high prevalence in Mediterranean regions, the Middle East, Southeast Asia, and the Indian subcontinent, with these populations showing carrier frequencies of approximately 1.5% globally. 1, 2
Geographic Distribution and Epidemiology
β-thalassemia major demonstrates the highest prevalence in areas with historical endemic malaria exposure, specifically:
- Mediterranean populations (particularly Italy, Greece, Cyprus) 3, 1
- Middle Eastern countries (including Iran, Iraq, Lebanon, Saudi Arabia) 3, 4
- South Asian populations (India, Pakistan, Malaysia, Thailand) 3, 2
- Southeast Asian regions where carrier rates approach significant percentages of the population 5, 2
The condition varies greatly in frequency worldwide, being most prevalent in these malaria-endemic regions, which is considered an evolutionary adaptation where carrier status provided protection against malaria 3.
Clinical Significance by Region
The prevalence data from international studies demonstrates marked regional variation in β-thalassemia major:
- Italy: Among the highest documented rates with 85.2% HCV co-infection prevalence in thalassemia cohorts, indicating large affected populations 3
- Middle East: Iran, Iraq, and Pakistan show substantial thalassemia populations with HCV co-infection rates ranging from 19.3% to 67.3% 3
- South Asia: India, Malaysia, and Thailand demonstrate HCV co-infection rates of 13% to 22.4% in thalassemia patients, reflecting significant disease burden 3
Important Clinical Context
β-thalassemia major requires lifelong transfusions (>8 transfusion events per year in adults over 16 years) and iron chelation therapy, distinguishing it from milder forms 3, 6, 7. The condition results from severe reduction or complete absence of β-globin chain production, causing life-threatening anemia by 1-2 years of age 3, 6.
Migration patterns have changed the epidemiology, with β-thalassemia prevalence now increasing in Northern Europe and North America due to population movement from endemic regions 5. This makes awareness of patient ancestry critical even in traditionally low-prevalence areas 1.
Key Clinical Pitfall
Do not overlook β-thalassemia trait in pregnant women of Mediterranean, Middle Eastern, or South Asian ancestry who present with persistent mild microcytic anemia unresponsive to prenatal iron supplementation 1. This requires further evaluation with MCV, RDW, and hemoglobin electrophoresis rather than continued empiric iron therapy 1.