GBD 2015: from big data to meaningful change
The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015) brings together the most recent epidemiological data according to year, age, and sex from 195 countries and territories. In a continuation of the partnership between The Lancet and the Institute for Health Metrics and Evaluation (IHME) this year marks the fi rst of an annual commitment to publish the four capstone GBD papers on global mortality, years lived with disability, disability adjusted life years, and risk factors in a single issue. 2015 also represents a key milestone in the global health and development community, with the end of the Millennium Development Goals (MDGs) era and the launch of the 17 Sustainable Development Goals (SDGs) Two health related MDGs maternal and child mortality are subjected to systematic analysis in this issue, and a third companion study aims to defi ne baseline measurements for health related SDGs. The GBD provides a window into the most pressing challenges and commendable achievements of the collective endeavour to transform human health and wellbeing. Although globally life expectancy has increased since 1980, confl ict and interpersonal violence has driven its stagnation or decrease in many regions, with male life expectancy in Syria decreasing by 11*3 years between 2005 and 2015. The combination of socioeconomic development and an ageing population is contributing to declines in some risk exposures, such as childhood undernutrition, but increases in others, such as low physical activity and high body mass index. Fundamentally, the GBD is about systematising everything we know about descriptive epidemiology to produce the most reliable global health statistics to date. This is the science of making data meaningful. As such, each iteration produces not only a worldwide update on disease burden, but, just as importantly, drives advances in the methods used to produce robust measurements and comparisons. Publication of the GBD in an academic journal is part of a deliberate eff ort to build a scientifi c discipline of estimation that is subjected to peer review and public scrutiny. It is this scientifi c rigour that makes the GBD an essential basis for achieving quantifi able progress in global health. At a national level, the GBD estimates support countries by enabling them to measure successes, identify important gaps, make comparisons with other countries, and set new priorities. These estimates are an important tool for policy makers, non governmental organisations, practitioners, and other stakeholders. Recent methodological refi nements have increased the granularity of estimates available for individual countries, increasing the ability to target resources to where they are needed most. China, Mexico, and the UK included the fi rst subnational level analyses in GBD 2013, with GBD 2015 expanding these analyses to also include several other countries such as Brazil, South Africa, Japan, and India. At the global level, the GBD functions as an accountability tool. Too often, high level targets, commitments, and goals pay scant attention to approaches for measuring their real world impact. Indeed, approaches for collecting and analysing data are scattered across the 17 SDGs and their individual targets and indicators, and are often found at the bottom of the priority list. The Socio demographic Index (SDI) is among the most important technological developments of GDB 2015. As a new indicator derived from measures of educational attainment, fertility rate, and per capita income, this index is critical to measuring the impact of public health interventions by separating secular trends that are driven by socioeconomic development from overall progress. In the baseline analysis for the SDGs, GBD 2015 produced a health related SDG index for each country and examined its relationship with the SDI, fi nding that some countries, including several in western Europe and Latin America, had SDG indices that were higher than expected on the basis of SDI alone, whereas others, such as the USA and India, performed poorer than expected. These fi ndings indicate that progress in health is achievable beyond the fl ow on eff ects of development status. Despite the gains made by 2015, considerable challenges remain. Crucially, the global health community needs to move beyond assessing individual health related SDGs to investigating the links between diff erent goals. There can be little doubt that factors such as education, access to clean water and sanitation, gender equality, and peace, justice, and strong civil institutions all have a profound impact on health. What is less clear, however, is how to analyse and measure these relationships. But measure them we must. Because what you don't measure you don't know, and what you don't know you can't act on. Good science is the start. The Lancet For more on the IHME see http:/www.healthdata.org/
The Lancet