The Population-Based Hungarian Twin Registry: Current Register Data, Researches and Linkages

Area of Science:

• * Population Health
• * Genetics
• * Epidemiology

Background:

• * Established at Semmelweis University, the Hungarian Twin Registry (HTR) has operated as a population-based registry since 2021.
• * Significant infrastructure expansion includes blood storage, IT systems, and administrative resources.
• * The HTR is now the largest population-based twin registry in Central and Eastern Europe.

Purpose of the Study:

• * To describe the establishment, infrastructure, and operational procedures of the Hungarian Twin Registry.
• * To report the initial registration numbers and demographic characteristics of participants.
• * To highlight the registry's potential for future health research, including data linkage.

Main Methods:

• * Population-based recruitment of adult twins and relatives of minor twins via website and voicemail.
• * Nationwide identification and notification process.
• * Registration via a comprehensive questionnaire covering sociodemographics, anthropometrics, lifestyle, and medical history.

Main Results:

• * By December 20, 2025, 12,676 individuals (7244 adult twins, 5432 parents/guardians) had registered.
• * Among registered adult twins, 44.1% were monozygotic (MZ) and 55.9% dizygotic (DZ); 68.4% were female.
• * Among registered children, 23.5% were MZ and 76.5% DZ.

Conclusions:

• * The Hungarian Twin Registry is a substantial resource for population-based research.
• * The registry's infrastructure supports diverse data collection and future linkage with national health databases.
• * Potential for long-term follow-up and disease-specific analyses, particularly in collaboration with registries like the Hungarian National Cancer Registry.