As the number of older people globally increases, health systems need to be reformed to meet the growing need for medical resources. A few previous studies reported varying health impacts of population ageing, but they focused only on limited countries and diseases. We comprehensively quantify the impact of population ageing on mortality for 195 countries/territories and 169 causes of death. Using data from the Global Burden of Disease Study 2017 (GBD 2017), this study derived the total number of deaths and population size for each year from 1990 to 2017. A decomposition method was used to attribute changes in total deaths to population growth, population ageing, and mortality change between 1990 and each subsequent year from 1991 through 2017, for 195 countries/territories and for countries grouped by World Bank economic development level. For countries with increases in deaths related to population ageing, we calculated the ratio of deaths attributed to mortality change to those attributed to population ageing. The proportion of people aged 65 years and older increased globally from 6.1% to 8.8%, and the number of global deaths increased by 9 million, between 1990 and 2017. Compared to 1990, 12 million additional global deaths in 2017 were associated with population ageing, corresponding to 27.9% of total global deaths. Population ageing was associated with increases in deaths in high-, upper-middle-, and lower-middle-income countries but not in low-income countries. The proportions of deaths attributed to population ageing in 195 countries/territories ranged from −43.9% to 117.4% for males and −30.1% to 153.5% for females. The 2 largest contributions of population ageing to disease-specific deaths globally between 1990 and 2017 were for ischemic heart disease (3.2 million) and stroke (2.2 million). Population ageing was related to increases in deaths in 152 countries for males and 159 countries for females, and decreases in deaths in 43 countries for males and 36 countries for females, between 1990 and 2017. The decreases in deaths attributed to mortality change from 1990 to 2017 were more than the increases in deaths related to population ageing for the whole world, as well as in 55.3% (84/152) of countries for males and 47.8% (76/159) of countries for females where population ageing was associated with increased death burden. As the GBD 2017 does not provide variances in the estimated death numbers, we were not able to quantify uncertainty in our attribution estimates. In this study, we found that population ageing was associated with substantial changes in numbers of deaths between 1990 and 2017, but the attributed proportion of deaths varied widely across country income levels, countries, and causes of death. Specific preventive and therapeutic techniques should be implemented in different countries and territories to address the growing health needs related to population ageing, especially targeting the diseases associated with the largest increase in number of deaths in the elderly.

Unintentional injury is the leading cause of death for children and adolescents between the ages of 1 and 18 in the United States, accounting for more deaths than the next 20 causes of mortality combined. It is estimated that pediatric injury accounts for more than $50 billion in annual losses from medical care costs, future wages, and quality of life. Despite these numbers, much remains to be learned about the behavioral risks for pediatric unintentional injury. This article reviews behavioral risk factors for pediatric unintentional injury risk, with a particular focus on four broad areas. First, we discuss the effects of demographic risk factors, including gender, socioeconomic status, and ethnicity. Second, we present information about child-specific risk factors, including temperament, personality, psychopathology, and cognitive development. Third, we discuss the influence of parents and other primary caregivers on childhood injury risk, with a particular focus on the effects of supervision and parenting quality and style. Finally, we discuss the role of peers on child injury risk. We conclude with a discussion of the ways in which the material reviewed has been translated into injury prevention techniques, with a focus on how pediatricians might use knowledge about etiological risk to prioritize safety counseling topics. We also present thoughts on four priorities for future research: injury risk in diverse nations and cultures; developmental effects of injury; the influence of multiple risk factors together on injury risk; and translation of knowledge about risk for injury into intervention and prevention techniques.