Longitudinal studies

The Wellcome Trust has committed support to longitudinal studies both in the UK and in developing or restructuring countries through special initiatives and through the ad hoc schemes (projects, programmes and fellowships) channelled through its Populations and Public Health funding stream.

Since 1996 we have contributed approximately £90 million in funding to 16 major longitudinal studies in partnership with various other funding bodies [Word 28KB].

These longitudinal studies include childhood [Word 44KB], adult [Word 40KB] and family cohorts and demographic surveillance systems (DSS) [Word 48KB].

The four UK-based cohort studies focus on non-communicable diseases in children [the National Child Development Study – the 1958 birth cohort, Avon Longitudinal Study of Parents and Children (ALSPAC) and TwinsUK] and adults (the UK Biobank).

The 12 non UK-based studies spanning Eastern Europe, Southern Africa, South America, Thailand and the Middle East focus on both infectious diseases such as malaria and HIV/AIDS, and other non-infectious chronic diseases.

Larger studies in the UK have generally been supported by defined partnerships with other funders (e.g. ALSPAC) or by providing specific support to a cohort with a range of existing funders (e.g. TwinsUK and the National Child Development Study). For example, the Trust has funded DNA/cell line resources to complement the existing wealth of phenotypic information available from established cohorts.

Longitudinal studies in developing countries have been supported by the Trust either through ad hoc schemes or though targeted initiatives under the Population Studies (1996-2000) and Health Consequences of Population Change (HCPC) (2000-2006) programmes. One of the aims of these initiatives has been to develop an evidence base for public health decisions in response to changing disease patterns resulting from urbanisation, lifestyle changes, ageing and migration. Given the very limited availability of high-quality demographic and disease-burden data to assist in health delivery policy in resource-constrained countries, there has been a particular focus on support for DSS sites.

Strategic issues for funding longitudinal studies

Coordination of funders

The Wellcome Trust will continue to consider funding longitudinal studies through its ad hoc schemes and through negotiating partnerships with other funders.

Opportunities to coordinate with other funders may be facilitated through initiatives such as the UK Medical Research Council (MRC) Longitudinal Studies Oversight Group. This 'cross-funder' committee was established by the UK MRC under the chairmanship of Professor Ian Diamond, CEO of the Economic and Social Research Council (ESRC), to bring together multiple funding agencies to drive a coordinated approach to the future development, management and funding of longitudinal studies.

At the international level, INDEPTH (International Network for the Demographic Evaluation of Populations and their Health Network) has provided a route for multiple agencies to come together to take an overview of DSS sites in low and middle-income countries and consider future sustainability of funding for these sites.

INDEPTH is an international network that seeks to add value to individual DSS sites across low and middle-income countries through taking an overview of DSS sites and coordinating multi-site studies, training and funding. The overall vision of INDEPTH is to establish an international platform of sentinel demographic sites that provides health and demographic data and research to enable developing countries to set health priorities and policies based on longitudinal evidence.

INDEPTH has 33 demographic surveillance sites in 18 different countries: 22 in Africa, nine in Asia, one in Oceania and one in Central America. Four of the INDEPTH sites receive funding from the Wellcome Trust, and more sites supported by the Trust are likely to become members of INDEPTH in the future. The majority of these sites focus on infectious diseases (at least 20, including nine focusing on malaria and eight focusing on HIV/AIDS), with six having a primary focus on non-communicable diseases (mental health, cardiovascular disease, nutrition) and six looking more broadly at health or health systems. Reproductive health is a theme running through many sites.

Data management

The Wellcome Trust and the UK MRC commissioned a report from Dr William Lowrance to explore the issues around access to collections of data and materials in health research. Issues discussed in this report include:

• ongoing data management and analysis
• data release and levels of access
• confidentiality and security
• long-term curation and archiving of data.

Genotyping

The advent of major investment in DNA resources to complement the phenotypic information already collected in the major UK cohorts will lead to a need for further investment in genotyping and single nucleotide polymorphism (SNP) analysis. Issues for funders include:

• genotyping capacity
• technology and cost
• quality control
• use of public and/or private sector services
• choice of targets (whole genome/HapMap targeted/candidate genes).