Understanding non-communicable diseases (NCD) and the role of infection in Africa: building a partnership to generate big data

"Non-communicable diseases" (NCD) are increasing in Africa. They are a diverse group of conditions, not directly caused by infections and are most often long-term and lifestyle-related, such as diabetes, high blood pressure, cancers, asthma and kidney disease. The reasons for the increase in these diseases are complex but include increasing urbanisation, overweight/obesity and lifestyle risk factors, such as smoking tobacco, high alcohol intake and reduced physical activity. The increase in NCD, is occurring alongside a high level of infectious disease (such as HIV and tuberculosis) and under- or mal-nutrition, which often exacerbates these conditions and leads to very poor health outcomes and shortens lives. In Africa, deaths from NCD in adults now exceed deaths caused by infectious diseases. To truly understand the severity and extent of these diseases requires investigations using detailed information from a general population, referred to as population-based research. Population-based research (as opposed to hospital-based research) is particularly important in Africa as relatively few people use formal health services, especially in the early stages of illness. The unique and valuable data collected in repeated cycles of population-based research help us to determine the amount and causes of disease; the risk (or chance) of death from these conditions; how these diseases develop in individuals; and how the disease changes over time (for example, age and sex of people most commonly affected). To understand NCDs in Africa better, and to help inform African policy makers and researchers, we propose an African NCD Longitudinal Data Alliance (ANDLA). ANDLA will bring together population-based research data from multiple partners working in existing study sites across Africa to create large, harmonised datasets that are robust and powerful enough to address important research questions that individual study sites would struggle to answer on their own. ANDLA will provide a dynamic and sustainable platform of population-based data collected over time (longitudinal-data). The data will be standardised and made available in an easily usable form, and will focus on NCD and their risk factors. It will be a unique large-scale data resource for understanding NCD in Africa now and in future decades, to inform and shape effective policy in populations with limited resources and a large and growing amount of these disease.

Global burden of disease estimates suggest NCD are overtaking infectious disease as the leading cause of adult mortality in Africa. Obesity, diabetes, hypertension and associated lifestyle risk factors are rising in urban and rural settings as populations age and urbanise. HIV-related cancers and those of infectious aetiology including liver and cervix, are highly prevalent, representing a higher fraction of total NCD burden in Africa than elsewhere. In future, cancers such as breast, lung and colon, will be increasingly important as countries undergo demographic transition. This is a critical time point to understand the epidemiology, phenotypes and determinants of NCD.
NCD data from LMIC are predominantly from small studies using differing methods. Evidence from adequately powered, "big" data platforms, of population-level data, is urgently needed to understand the burden, distribution and determinants of NCD and the intersection with HIV and other important infectious diseases. We propose to set up an African Non-communicable Disease Longitudinal data Alliance (ANDLA) to address this gap: working with policy makers and experienced research partners; bringing together partners with NCD data collected in demographic surveillance sites to address important questions relevant to our setting. This will enable a greater understanding of the current status of chronic NCD, provide evidence for future prevention and management strategies and build a platform for multi-site intervention development, monitoring and evaluation and health systems research. Longitudinal data are key to understanding disease progression, trends and contribution of risk factors to mortality.
We will analyse markers of cardio-metabolic mortality risk; develop and validate risk scores; and conduct analyses of HIV-related cancer mortality. Scientific advisory groups will inform future work which may include asthma, chronic kidney disease, disabilities, injuries, epilepsy and mental health.

The aim of the African Non-communicable Disease Longitudinal data Alliance (ANDLA) is to provide policy relevant data and analyses to national, regional and international bodies. It is anticipated that our policy briefs on burden and risk factors of NCD conditions will be used by Ministries, and regional and national bodies such as the NCD Alliance and WHO. These groups are active in determining policy, creating guidelines for managing NCD in LIMC and lobbying internationally for an effective global response. Overall we expect that findings from ANDLA will have a substantive influence on the decisions made by stakeholders to address the health care priorities of these populations.
Each partner institution has close relationships with local policy makers, through National Research Institutes, Public Health Institutes, other Ministry of Health departments and other Ministries involved in the multi-sectoral response to NCD. These have the local remit to lobby parliamentarians and lawmakers to respond appropriately with legislation (and the political will to enforce this) in the areas most likely to have impact on future NCD. Our capacity to provide high quality research evidence to these bodies will facilitate the development of evidence-informed legislation in important areas including alcohol, tobacco, sugar and town-planning (to enable increased physical exercise in urban communities). It will support Ministries of Education and Nutrition to take the lead in mainstreaming NCD prevention messages into Personal Social and Health Education programmes in schools and colleges, and to the wider community.
As part of the foundation phase, ANDLA partners will engage with national stakeholders, to solicit input for the Alliance's research agenda and to ensure that policy-relevant questions are addressed. Stakeholders involved in co-ordinating the multi-sectoral approach to NCD prevention and scale-up of response will be particularly important in refining research questions. Host country stakeholders will be invited to the presentation days on each selected topic. Our findings will be communicated through dissemination in national meetings and policy briefings. We anticipate that the Alliance output will be highly influential in both the international and national fora where our high quality evidence will help direct the urgently-needed health care response.