The starting point for the study was the identification of 220 unique consequences of disease and injury identified in GBD 2010 as causing disability (defined as any short-term or long-term loss of health). These consequences of disease and injury are known as sequelae, and include common ailments such as headache or tooth decay, as well as specific diseases such as autism or gout. The advantage of analysing the sequelae of disease is that it allows researchers to understand the prevalence of specific health problems; analysing disease classification only might miss the important role that sequelae such as anaemia or vision loss – which may be caused by a number of different diseases or injuries – might play in overall population health.
The authors measured the impact of each of the sequelae identified by measuring the years lived with disability (YLD) for each of them. This measure uses the product of disability weight (the relative severity of each sequela – see paper 4), and its prevalence (i.e. the proportion of the population with the sequela in the year of interest). The prevalence was obtained through a comprehensive examination of published research, health care data (e.g. hospital discharges, cancer registries), and other sources such as surveys. YLDs were estimated for 1990 and 2010.
Surprisingly, despite the fact that other parts of GBD 2010 have identified substantial changes in the patterns of mortality seen between 1990 and 2010, this analysis revealed that the sequelae which result in the largest overall health loss have changed remarkably little in the last twenty years. Lower back pain, depression, iron-deficiency anaemia, and neck pain were the top four sequelae responsible for the greatest overall health loss (measured in terms of YLDs) in both 1990 and 2010.
In 2010, the two disease categories responsible for almost half of all YLDs – and therefore the largest overall health impact –were musculoskeletal disorders (such as arthritis and back pain), and mental and behavioural disorders (such as depression, schizophrenia, and drug and alcohol use disorders).
According to Professors Alan Lopez and Theo Vos, both of the School of Population Health of the University of Queensland, and authors of the study, "In an era in which the Millennium Development Goals (MDGs) have focused global health attention on prevention of mortality from selected diseases, it is important to realise that health is about more than avoiding death. Health priorities have, for much of the past 100 years or more, been largely driven by the imperative of improving the survival of populations, particularly child survival. This was justified, in view of the technologies available to treat and prevent childhood illness. However, societies spend substantial and increasing resources on keeping people healthy and alleviating disease, not only on keeping them alive into old age. As health care costs are rising fast, it is essential to provide governments with adequate information on how best to prioritise their health services to most adequately address the prevailing health problems."
NOTE TO EDITORS:
*Of the 291 diseases and injuries in the GBD cause list, 289 cause disability.
Journal
The Lancet