MRC-funded research carried out in and around the town of Farafenni, in the North Bank Region of The Gambia, is contributing towards the largest ever dataset of individual deaths recorded on-the-ground.Published today, the dataset provides an unprecedented insight into the changing health of people across Africa and Asia – including the fluctuating burdens of malaria, childhood diseases and non-communicable diseases. The data demonstrate the value of recording cause of death for planning and improving public health services.

In The Gambia, relevant data was collected routinely by researchers from MRC Unit The Gambia in a population of about 45,000 people, as part of the Farafenni Health and Demographic Surveillance System (HDSS) operated by the MRC Unit in The Gambia.

The Farafenni HDSS was established in the North Bank Region of The Gambia in 1981, in 42 rural villages to the east and west of the town of Farafenni. In October 2002, the surveillance area was expanded to include Farafenni Town and 23 settlements within a 5km radius of the town. Interviews conducted for deaths that occurred between 1998 and 2007 were used to evaluate the cause-of-death patterns and to establish the impact of specific diseases in this part of The Gambia.

Overall, more than 110,000 individual deaths and their causes over 12 million person-years of observation across 13 countries, including The Gambia, Ghana, South Africa, Kenya, Bangladesh and Vietnam, are contained in the new INDEPTH Network dataset. The INDEPTH Network is one of the few international population health agencies based in the global South. Based in Ghana, it serves as an umbrella organisation for 45 research centres that run 52 Health and Demographic Surveillance System (HDSS) sites in 20 low- and middle-income countries, each following individuals in defined populations on a continuous basis.

The data, collected by hundreds of researchers over two decades in 22 health and demographic surveillance sites, are the first meaningful community-based information about cause of death in countries where individual deaths are not routinely recorded by national governments. A structured interview with a family member of the deceased, was conducted for each death and computer processed to establish likely causes of death.

The INDEPTH cause-of-death findings are published in a special issue of the journal Global Health Action, which is fully open access. There are six multisite papers dealing with specific causes of death: HIV/AIDS, malaria, pregnancy-related, external causes (including accidental death and suicide), adult non-communicable diseases and childhood illness; data from the Farafenni HDSS in The Gambia supports five of these papers. Other papers describe methods, and many sites have contributed papers with local details, including the Farafenni HDSS in The Gambia.

Data collected by the Farafenni HDSS give the first indication ever of the cause-specific mortality pattern for a geographically defined population in The Gambia. The analysis showed that three preventable and treatable diseases – malaria, acute respiratory infection and diarrhoeal diseases – accounted for three out of every five deaths among children under 5 years old between 1998 and 2007. It also showed that communicable diseases, especially pulmonary tuberculosis, constitute the greatest mortality burden among adults between the ages of 15 and 59 years.

The study confirms the prevalence of the double burden of communicable and non-communicable diseases in this rural population in The Gambia, which undoubtedly constitutes a huge strain on the local health care delivery system.

The entire dataset (also now available in the public domain), which at some sites includes cause-of-death data collected as far back as 1992, represents more than a century of working time. It also proves that data relating to cause of death can be reliably collected by non-medical staff outside of a clinical setting.

Overall, the data provide a strong case for the value of recording cause of death for planning and improving public health services. They show high variability in cause of death across sites. Although the picture is complex, there is some evidence to link mortality with differing investment in healthcare over the two decades of the study.

The INDEPTH collaboration is able to estimate the global burden of major diseases. Furthermore, unlike other mortality estimates, such as the ones made by United Nations agencies and the Global Burden of Disease project in Seattle that are based on mathematical models, the INDEPTH estimates are based on information about real deaths in defined areas of the population. Encouragingly for researchers, the findings of INDEPTH are very similar to the outputs from the mathematical modelling techniques, indicating that they confirm each other.

Momodou Jasseh, MRC Unit Demographer and lead author of the Farafenni site paper, said: “This study has confirmed that it is possible to generate representative cause-of-death structure for a typical sub-Saharan African population where most deaths occur outside of the health system. The next step is to roll the method outside the research setting and incorporate interviews with relatives into the national vital registration system. This will undoubtedly yield much needed health information to facilitate resource allocation at the respective health regions of the country. We would like to thank the residents of the Farafenni HDSS and all the respondents who agreed to participate in the interviews”.

Professor Umberto D’Alessandro, Director of MRC Unit The Gambia, said: “The HDSS is an essential tool for our research activities. It provides information on the burden and evolution of prevailing diseases, and helps in the formulation of relevant research questions and design of adequate interventions to improve the health of the Gambian population”.

“A fundamental achievement of INDEPTH that should encourage an international discourse on cause-specific mortality in these resource-poor settings," said Marcel Tanner, Chair of the INDEPTH Board of Trustees, Director of the Swiss Tropical and Public Health Institute in Basel, Switzerland.

Ties Boerma, Director of Health Statistics and Information Systems at the World Health Organization, who has written an accompanying editorial for the special issue of Global Health Action, said that INDEPTH “presents the largest dataset of this nature ever,” adding that this work “needs to be considered in the context of the need to strengthen country Civil Registration and Vital Statistics systems, and should be a central element in the post-2015 development agenda.”

Reference

Jasseh, M., S.R.C. Howie, P. Gomez, S. Scott, A. Roca, M. Cham, B. Greenwood, T. Corrah, and U. D'Alessandro. 2014. "Disease-specific mortality burdens in a rural Gambian population using verbal autopsy, 1998-2007." Glob Health Action 7: 25598:http://dx.doi.org/10.3402/gha.v3407.25598.

All the papers published from the INDEPTH Network are available in a special issue of http://dx.doi.org/10.3402/gha.v3407.25598.