Role of ethnicity and residency in active tuberculosis in Karakalpakstan: study protocol of a matched case-control study.

Introduction: Uzbekistan is one of the 30 countries with the highest tuberculosis (TB) morbidity, accounting for 87% of all cases globally. The incidence of TB in the Republic of Karakalpakstan (RK) remains consistently high in comparison with other regions of Uzbekistan. The incidence rates of TB strongly differ even among the regions within RK. In 2019, the highest rates were registered in the northern and north-western regions, and the lowest in the southern regions. An important issue is the extent to which specific residencies impact individual health. The ethnic composition of the population of RK can be one of the possible causes for such geographical heterogeneity in TB morbidity.

Methods and analysis: The case-control design of this study primarily aims to evaluate the role of ethnicity and residency on the development of active TB in the community living in RK. Additionally, the study aims to measure the association between factors of TB morbidity and ethnicity/residency in the community of RK. It was decided to include one matched control for every included case, to control potential confounders. Cases with clinically diagnosed or bacteriologically confirmed TB will be randomly sampled from the patient registry. Controls will comprise individuals without TB, living in RK at the same time as the cases. They will be randomly sampled from a general roster of the residents.

Ethics and dissemination: This study was approved by the Bioethics Committee of the Medical Association of Uzbekistan (approval report of meeting #1 on 18 January 2024). The results of this study will be widely disseminated at scientific meetings and conferences, and published in a peer-reviewed journal.