Sciensano leads the Belgian National Burden of Disease Study (BeBOD), which provides a coherent framework for routinely quantifying the burden of disease in Belgium using the Disability-Adjusted Life Year (DALY) metric.
Burden of disease
Burden of disease
Public health policy aims to promote and protect population health. This requires information on the health status of the population, often referred to as the “burden of disease”. More than just the presence/absence of specific diseases, disease burden encompasses measuring the impact of diseases and risk factors on physical and psychosocial health in a comprehensive and comparable way.
How to estimate the burden of disease
The disease burden of a population can be described by a variety of indicators. Typical indicators of population health are life expectancy, cause-specific mortality rates, numbers of new and existing cases of specific diseases (i.e. incidence and prevalence), and self-perceived health. Each of these indicators points to either mortality or morbidity, the 2 core facets of health. With ageing populations and the growing importance of non-fatal diseases, current evidence-based public health policy requires a global overview of population health, combining these facets and taking account of health-related quality of life.
Summary measures of population health such as the Disability-Adjusted Life Year (DALY) have therefore become key metrics for quantifying burden of disease. DALYs measure the health gap by comparing a life lived in perfect health to reality. The health gap is thus defined as the number of potentially healthy life years lost due to morbidity, disability and mortality. A disease burden of 100 DALYs per 1000 people-year would thus imply a loss of 100 healthy life years per 1000 people per year. The more DALYs diseases or risk factors account for, the higher their impact on population health.
By enabling the calculation of the total disease burden and the contribution of different diseases and risk factors, DALYs are a highly valuable measure to set priorities for public health research and policy. Furthermore, DALYs may be calculated for different (sub)populations (e.g. gender, geographical areas, socioeconomic groups), allowing for a more detailed perspective on population health. By regularly updating the DALY estimates based on the best available data, trends in population health can be monitored over time, and the impact of macro-level policies can be evaluated. As a result, DALYs are an important tool to support policies that aim to improve population health and reduce health inequalities.
Burden of disease studies in Belgium
Estimates on the burden of disease in Belgium, expressed as Disability-Adjusted Life Years (DALYs), are available from both international and national efforts. To date, the most comprehensive sources of disease burden estimates for Belgium are the Global Burden of Disease studies conducted by the World Health Organization and by the Institute for Health Metrics and Evaluation (IHME).
So far, only few national efforts have been undertaken to study the disease burden in Belgium. The use of DALYs as a policy-relevant instrument in Belgium was first described in the Flemish Health Indicator Report 1998. Since then, several researchers have estimated the burden of single specific health conditions or risk factors in Belgium, e.g. environmental risk factors, road traffic accidents, haemophilia, melanoma and specific congenital and foodborne infections.
Despite these efforts, several constraints hamper the policy relevance of the currently available estimates. While global estimates provide a broad overview of the health status in Belgium, it remains a question to what extent these estimates are grounded in the best available local data. These global exercises are currently also not able to respond to country-specific needs, such as breaking up the data into meaningful subsets to enable the assessment of disease burden at regional levels.
On the other side, while national research groups have undertaken more efforts to use local data sources, there appears to be little consistency in the applied DALY calculation methodology. As a result, the generated estimates in Belgium are not comparable, hampering the main use of DALYs as a tool for comparison and prioritisation. Most DALY estimations also remained academic exercises, with little or no direct knowledge transfer to the concerned policy makers. Therefore, if disease burden were to support health policy, a more systematic approach is required, generating comparable estimates rooted in recent, local data.