Foreword: INDEPTH WHO-SAGE study.

My foreword to the first INDEPTH supplement published in GHA, which comprised a series of papers by the INDEPTH NCD Surveillance in Asia Working Group, stated that the work demonstrated ‘the increasing ability of the INDEPTH Network to harness the collective potential in Health and Demographic Surveillance Systems in low- and middle-income countries to provide a better, empirical understanding of health issues of populations under continuous evaluation.’ In that foreword I also noted, ‘with that collaborative research, we have seen some of the objectives of INDEPTH being achieved: we have strengthened the capability of several of our young scientists to conduct and analyse longitudinal health and demographic studies; and some of them have become first authors of scientific papers for the first time’ (1).

The current supplement, by the INDEPTH Adult Health and Ageing Working Group, is a compilation of a series of excellent site-specific and cross-site papers, which has reinforced the opinions I expressed previously.

I feel privileged to be writing these forewords at a time when these studies are being completed and their results are being disseminated in scientific publications. The INDEPTH WHO-SAGE collaboration started several years ago during the tenure of office of my predecessor, Professor Fred Binka. It was he who provided the initial support to the Adult Health and Ageing group, enabling it to engage with WHO in this partnership. I therefore wish to share with him the credit for this success.

I am delighted to have taken part in two key analysis workshops graciously hosted by the Umeå Centre for Global Health Research, Umeå University, Sweden in 2008, and by the Harvard Centre for Population and Development Studies, Cambridge, MA, USA in 2010. I am also well aware of those previously hosted by the University of Witwatersrand's School of Public Health as well as the WHO, more recently in June 2010. I saw INDEPTH scientists presenting their work and taking part in rigorous data analysis, and witnessed exemplary collaboration demonstrated by our partners in Umeå and Boston. They contributed expertise and resources to strengthen the capacities of our scientists to take leading roles in this work.

While in Umeå and Boston, I saw our colleagues there demonstrating expertise in data analysis and in how to interrogate and make sense out of data that had been collected thousands of miles away. That experience made me feel that there was a great need for INDEPTH to establish a training centre for health and demographic surveillance systems so that many more scientists from low- and middle-income countries could be trained in complex longitudinal data analysis techniques.

On behalf of the INDEPTH Board and myself, I wish to thank the World Health Organization who have been exemplary partners in this collaboration, and also the key funder, National Institute on Aging, National Institutes of Health (NIA, NIH). I wish to highlight the pivotal role played by Dr. Richard Suzman (NIA, NIH) who ‘was always there’ as a funder and competent scientist during this collaboration and is the Senior Editor of this Supplement. I also want to acknowledge the Health and Population Division, School of Public Health, University of the Witwatersrand, South Africa, for its ongoing role as satellite secretariat of the INDEPTH Adult Health and Ageing Working Group. This multi-site and multi-country INDEPTH project has succeeded because of the commitment and scientific leadership of Professor Stephen Tollman, the leader of the INDEPTH Adult Health and Ageing Working Group. Furthermore, I wish to appreciate the advice provided by the INDEPTH Advisory Committee through its member Professor Stig Wall at Umeå University.

Through resources provided for core institutional support to INDEPTH by the Wellcome Trust, Sida/GLOBFORSK, Rockefeller Foundation, Gates Foundation and Hewlett Foundation, we were able to contribute financially to the Adult Health and Ageing Working Group for the successful completion of this work. I was happy to learn of WHO's success in securing further resources from NIA, NIH for a Phase II of these INDEPTH WHO-SAGE studies and, in this regard, look forward to our continuing collaboration.

The dataset generated by these studies is being made freely available and INDEPTH will encourage wider use of the data.

Congratulations!

Osman Sankoh

Executive Director, INDEPTH Network