Bill & Melinda Gates Foundation.

Background In 2010, overweight and obesity were estimated to cause 3.4 million deaths, 3.9% of years of life lost, and 3.8% of DALYs globally. The rise in obesity has led to widespread calls for regular monitoring of changes in overweight and obesity prevalence in all populations. Comparative, up-to-date information on levels and trends is essential both to quantify population health effects and to prompt decision-makers to prioritize action. Methods We systematically identified surveys, reports, and published studies (n = 1,769) that included information on height and weight, both through physical measurements and self-reports. Mixed effects linear regression was used to correct for the bias in self-reports. Age-sex-country-year observations (n = 19,244) on prevalence of obesity and overweight were synthesized using a spatio-temporal Gaussian Process Regression model to estimate prevalence with 95% uncertainty intervals. Findings Globally, the proportion of adults with a body mass index (BMI) of 25 or greater increased from 28.8% (95% UI: 28.4-29.3) in 1980 to 36.9% (36.3-37.4) in 2013 for men and from 29.8% (29.3-30.2) to 38.0% (37.5-38.5) for women. Increases were observed in both developed and developing countries. There have been substantial increases in prevalence among children and adolescents in developed countries, with 23.8% (22.9-24.7) of boys and 22.6% (21.7-23.6) of girls being either overweight or obese in 2013. The prevalence of overweight and obesity is also rising among children and adolescents in developing countries as well, rising from 8.1% (7.7-8.6) to 12.9% (12.3-13.5) in 2013 for boys and from 8.4% (8.1-8.8) to 13.4% (13.0-13.9) in girls. Among adults, estimated prevalence of obesity exceeds 50% among men in Tonga and women in Kuwait, Kiribati, Federated States of Micronesia, Libya, Qatar, Tonga, and Samoa. Since 2006, the increase in adult obesity in developed countries has stabilized. Interpretation Because of the established health risks and substantial increases in prevalence, obesity has become a major global health challenge. Contrary to other major global risks, there is little evidence of successful population-level intervention strategies to reduce exposure. Not only is obesity increasing, but there are no national success stories over the past 33 years. Urgent global action and leadership is required to assist countries to more effectively intervene.

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Bill & Melinda Gates Foundation.

SummaryBackgroundExposure to ambient air pollution increases morbidity and mortality, and is a leading contributor to global disease burden. We explored spatial and temporal trends in mortality and burden of disease attributable to ambient air pollution from 1990 to 2015 at global, regional, and country levels.MethodsWe estimated global population-weighted mean concentrations of particle mass with aerodynamic diameter less than 2·5 μm (PM2·5) and ozone at an approximate 11 km × 11 km resolution with satellite-based estimates, chemical transport models, and ground-level measurements. Using integrated exposure–response functions for each cause of death, we estimated the relative risk of mortality from ischaemic heart disease, cerebrovascular disease, chronic obstructive pulmonary disease, lung cancer, and lower respiratory infections from epidemiological studies using non-linear exposure–response functions spanning the global range of exposure.FindingsAmbient PM2·5 was the fifth-ranking mortality risk factor in 2015. Exposure to PM2·5 caused 4·2 million (95% uncertainty interval [UI] 3·7 million to 4·8 million) deaths and 103·1 million (90·8 million 115·1 million) disability-adjusted life-years (DALYs) in 2015, representing 7·6% of total global deaths and 4·2% of global DALYs, 59% of these in east and south Asia. Deaths attributable to ambient PM2·5 increased from 3·5 million (95% UI 3·0 million to 4·0 million) in 1990 to 4·2 million (3·7 million to 4·8 million) in 2015. Exposure to ozone caused an additional 254 000 (95% UI 97 000–422 000) deaths and a loss of 4·1 million (1·6 million to 6·8 million) DALYs from chronic obstructive pulmonary disease in 2015.InterpretationAmbient air pollution contributed substantially to the global burden of disease in 2015, which increased over the past 25 years, due to population ageing, changes in non-communicable disease rates, and increasing air pollution in low-income and middle-income countries. Modest reductions in burden will occur in the most polluted countries unless PM2·5 values are decreased substantially, but there is potential for substantial health benefits from exposure reduction.FundingBill & Melinda Gates Foundation and Health Effects Institute.