December 13, 2012
Health progress requires more than simply delaying death or increasing life expectancy at birth. The presence of non‐fatal disease and disability are also very important considerations.
Over the last six decades, advances in medicine and public health, improved living standards, rising levels of education, and declines in fertility have contributed to dramatic reductions in mortality in most regions of the world. With the accompanying trend of population aging, there is increased recognition of the need to prioritize health in the later years of life.
Healthy life expectancy, or HALE, is a measure of average population health summarizing both mortality and non‐fatal outcomes. HALE is used for comparisons of health across countries or for measuring change over time. These comparisons can shed light on key questions about how morbidity worsens or improves as mortality declines.
HALE was calculated by extending the conventional life table that is used to translate a schedule of agespecific death rates into estimates of life expectancy at different ages. Information on the average level of health experienced over each age interval was incorporated into the life table.
Three sets of inputs from GBD 2010 were used, including age‐specific information on mortality rates and prevalence of 1,160 conditions resulting from specific diseases, by sex, country, and year, and disability weights associated with the set of 220 distinct health states relating to those sequelae.
Estimates of average levels of overall health were computed for each age‐sex group, adjusting for comorbidity using a Monte Carlo simulation approach to capture the many ways in which multiple prevalent morbidities may combine in a given individual. These estimates of average health were incorporated in the life table using the Sullivan method, yielding healthy life expectancy estimates for each population in the study.
Results were evaluated across country and over time, and changes were evaluated to estimate the relative contributions of changes in child mortality, adult mortality, and disability prevalence as drivers of overall change in population health between 1990 and 2010.
Gains in healthy life expectancy over the last two decades have been made primarily through reductions in child and adult mortality rather than reductions in years lived with a disability.
In 2010, global HALE at birth was 58.3 years for males and 61.8 for females, compared to 54.4 and 57.8, respectively, in 1990. The difference between life expectancy and HALE was 9.2 years for males and 11.5 years for females. The study also found that females lose more healthy life to disability than males between the ages of 15 and 65.
While life expectancy at birth increased by 4.7 years for males and 5.1 years for females, HALE at birth increased only 3.9 years and 4.0 years, respectively. This indicates that, on average, the world’s population surrenders more years of healthy life to various disabilities today than 20 years ago. Overall the gap between the sexes in both life expectancy and HALE continues to widen, as gains have been higher for women in both life expectancy and HALE.
HALE overall has increased in 19 of 21 regions, with the two dramatic exceptions being southern sub‐ Saharan Africa, where adult mortality from HIV/AIDS has erased years of life expectancy, and the Caribbean, where the 2010 earthquake in Haiti produced exceptionally high mortality that resulted in one‐time massive reductions in life expectancy. Across countries, HALE at birth in 2010 for males ranged from 27.9 in Haiti to 68.8 in Japan, and HALE at birth for females ranged from 37.1 in Haiti to 71.7 in Japan.
Prevention campaigns have succeeded in a range of infectious diseases, but they have yet to make progress on a large scale for a larger number of diseases and injuries that have left people functionally impaired. The failure to make significant progress in reducing the overall health impact of these diseases and injuries over the last 20 years should be cause for alarm and action.
Target‐setting exercises for health, such as the Millennium Development Goals (MDGs), have focused on reducing mortality from causes such as HIV, tuberculosis, and malaria, with varying results. However, there have been minimal changes in the overall prevalence of disability because such campaigns have not yet addressed diseases and injuries that leave people functionally impaired. HALE will likely be a useful indicator that could inform discussions about global health goals and targets for the post‐MDG era.
Countries are facing a coming wave of financial and social costs from the rising number of people living with diseases and injuries. The net effect on healthcare costs depends on the balance of costs associated with conditions such as diabetes, musculoskeletal disorders, mental and behavioural disorders and other leading contributors to disability, versus the costs of medical care.
If all countries could achieve the low years‐lived‐with‐disability per capita rates seen in Japan, for example, substantial increases in healthy life expectancy would be realized. These improvements would likely be accompanied by reductions in the costs of managing diseases and injuries.
Salomon JA, Wang H, Freeman MK, Vos T, Flaxman AD, Lopez AD, Murray CJL. Healthy life expectancy for 187 countries, 1990–2010: a systematic analysis for the Global Burden Disease Study 2010. The Lancet. 2012 Dec 13; 380: 2144–2162.