There is very little genetically informative research identifying true environmental risks for psychiatric conditions. These may be best explored in regions with diverse environmental exposures. The current study aimed to explore similarities and differences in such risks contributing to depression and fatigue.
Category: Papers
Susceptibility to depression results from genetic and non-familially shared environmental influences in high-income, Western countries. Environments may play a different role for populations in different contexts.
The Sri Lankan twin registry is one of the first to be established in a developing country, and its design has ensured sampling from a wide range of environmental conditions. It thus has great potential to examine environmental and genetic influences on diverse phenotypes, including psychiatric disorders, in the context of a diversity of environmental exposures, which may not have been fully explored in previous twin studies in developed countries. This paper presents the rationale for the study, describes its context, and the methods for twin ascertainment and data collection.
The Sri Lankan Twin Registry began as a volunteer register in 1997. Previously, we have shown door-to-door surveys as the best option to build a population-based twin register of older, adult twins. Our aim was to build a population-based twin register in the Colombo district and use it for twin studies on common mental disorders.
The National Twin Registry of Sri Lanka was established in 1997 as a volunteer register. To extend it to a population-based register, we examined the effectiveness of tracing older twins by inspecting birth records and recruiting them by postal invitation and in-person contact. Birth records at a divisional secretariat reported from 2 maternity hospitals between the years of 1954–1970 were scrutinised to identify a random sample of twins.
Sri Lanka is an island with genetic diversity between the five main population groups. Our twin registry is the first in the developing world. Initially, we established a volunteer cohort of 4600 twin pairs through a competition advertised in the media
Identifying twins for a population-based register can be achieved through birth records or community surveys. We studied the feasibility and effectiveness of different methods of identifying and recruiting twins to establish a population based register.
Nearly all twin registers are based in developed countries and there is no twin register in the developing world. Our objectives were to initiate the process of establishing a nationwide twin register in Sri Lanka by starting a volunteer register first and working towards a population-based register. Regular newspaper advertisements, feature articles, radio talks, and television programmes were used to publicise a competition for twins, their parents/relatives and friends requesting them to participate by sending in details of twins.
We report the process of adaptation into Sinhala of a questionnaire given to mothers of twins to determine zygosity. Adaptation and validation was carried out in three stages. Firstly, we used a nominal group to translate the English version and to assess the extent of agreement (consensus measurement) on the appropriateness of the translation and resolve disagreement (consensus development)