Identification and Development of a High-Risk District Model in the Prevention of β-Thalassemia in Telangana State, India.

The burden of β-thalassemia (β-thal) is largely underestimated in India with a carrier frequency of 3.0-4.0% in general, whereas highly stratified frequencies of up to 17.0% are reported in local endogamous subpopulations. We have no idea whether β-thal carrier frequencies or β-thal major (β-TM) births are increasing or decreasing in the population. The cross-sectional nature of all carrier screening programs including large-scale task force and micro level, lack of registration of β-TM births and mechanism to modulate knowledge, awareness programs in a long-term perspective, all preempt impact assessment of preventive programs. During the implementation of a Telangana State Government-sponsored program on 'Micro profiling of β-thalassemia mutations in Telangana,' we documented extensive in-depth demographic information on each β-TM child of the study sample that included age-sex distributions, parental and grand-parental ethnic affiliations (local endogamous group level), birth places, marital migrations, endogamy and consanguinity to identify high-risk districts as ethno-geographic regions. In Telangana State, we found β-thal is widely prevalent in 31 districts and 48 local endogamous subpopulations. The present study provided a method of identification of four 'high-risk districts' and developed a district model for prevention on high priority in Telangana State. The model has the advantage of impact-assessment of all preventive programs in the district.