India's Opportunities and Challenges in Establishing a Twin Registry: An Unexplored Human Resource for the World's Second-Most Populous Nation

Tracing ocular biometry and their heritability in twins in a hospital-based cohort in South India

PURPOSE

Twin studies, in the background of lack of twin registry in India, are a challenge. We report the response rates in tracing a hospital birth register-based cohort of twins using mail and door to door survey, ocular parameters influencing refractive errors, and their heritability.

METHODS

Twins born from 1991 to 1995 in a tertiary hospital in the Vellore District of South India from a database were traced by mail and home survey from March 2011 to September 2013. Consenting live twin pairs who presented to the eye department were examined, including best corrected visual acuity, cycloplegic refraction, slit lamp examination, measurements of intraocular pressure (IOP) by Goldmann Applanation tonometry, axial length (AL) and anterior chamber depth (ACD), central corneal thickness (CCT), specular microscopy for endothelial count (EC), and a dilated fundus examination. Zygosity was determined by a validated zygosity questionnaire. Heritability was determined using the Falconers formula.

RESULTS

Postal contact was made in 14%, and a home visit was successful in another 23% of the cohort. Of those presenting for examination, 51.3% were found to be monozygous. Heritability (h 2 ) of IOP was 0.34, that of ACD was 0.88, that of AL was 0.92, that of CCT was 0.96, and that of EC was 0.58.

CONCLUSION

Tracing of twins using postal and home visits is challenging. Heritability for AL and CCT was found to be high, similar to that reported in other studies. This implies that a large proportion of variation found in AL and CCT is due to genetic causes as seen in twins from South India.

Conceptual framework for establishing twins prevention and continuous health promotion programme: a qualitative study

BACKGROUND

Twin registries and cohorts face numerous challenges, including significant resource allocation, twins' recruitment and retention. This study aimed to assess expert feedback on a proposed pragmatic idea for launching a continuous health promotion and prevention programme (HPPP) to establish and maintain twin cohorts.

DESIGN

A qualitative study incorporating an inductive thematic analysis.

SETTING

Tehran University of Medical Sciences.

PARTICIPANTS

Researchers with expertise in twin studies participated in our study.

ANALYSIS AND DESIGN

Expert opinions were gathered through focus group discussions (FGDs). Thematic analysis was employed to analyse the findings and develop a model for designing a comprehensive, long-term health promotion programme using ATLAS.ti software. Additionally, a standardised framework was developed to represent the conceptual model of the twin HPPP.

RESULTS

Eight FGDs were conducted, involving 16 experts. Thematic analysis identified eight themes and seven subthemes that encompassed the critical aspects of a continuous monitoring programme for twin health. Based on these identified themes, a conceptual framework was developed for the implementation of an HPPP tailored for twins.

CONCLUSION

This study presented the initial endeavour to establish a comprehensive and practical solution in the form of a continuous HPPP designed to tackle the obstacles of twins' cohorts.