Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation

Subgrade Soil Evaluation for the Design of Airport Flexible Pavements

336 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1999.The concepts and procedures developed in this study are based on a comprehensive laboratory testing conducted with the National Airport Pavement Test Facilities (NAPTF) cohesive subgrade soils. NAPTF full-scale pavement data will be used to validate the concepts and procedures.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Subgrade Soil Evaluation for the Design of Airport Flexible Pavements

336 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1999.The concepts and procedures developed in this study are based on a comprehensive laboratory testing conducted with the National Airport Pavement Test Facilities (NAPTF) cohesive subgrade soils. NAPTF full-scale pavement data will be used to validate the concepts and procedures.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Summary of Construction Activities and Results from Six Initial Accelerated Pavement Tests Conducted on Asphalt Concrete Pavement Section for Modified-Binder Overlay

This report summarizes the activities and data collected during the construction of a pavement section used for investigating the performance of asphalt concrete pavements under accelerated pavement testing. This report also presents the preliminary results of six accelerated pavement tests conducted on the test section.The pavement section was constructed in September 2001 at the Pavement Research Center, located at the University of California Richmond Field Station. The construction was performed by a highway contractor with the purpose of simulating highway paving operations. Under these conditions, the results from the tests can be translated into predicting the behavior of actual in-service pavements.The pavement was composed of 90 mm of asphalt concrete, and 410 mm of recycled aggregate base on top of a prepared 200 mm subgrade. The layer thicknesses were designed according to Caltrans design procedures and checked using mechanistic methods to ensure limited rutting in the subgrade.Preparation and construction of the subgrade, aggregate base, and asphalt concrete were completed according to Caltrans practice. Compaction of the asphalt concrete was controlled based on the maximum theoretical density of the mix.Average in-situ relative densities for the subgrade and aggregate base were above 95 percent. Average air-void contents in the asphalt concrete layer were between 7 and 10 percent. Average thickness was 79 mm. Asphalt extractions from two samples indicated binder content by weight of aggregate of between 4.3 and 5.7 percent. The target binder content was 5.0 percent.Deflection testing conducted during the construction of the pavement section showed the effect of the asphalt concrete layer on the behavior of the aggregate base and subgrade layers. The asphalt concrete provided an increase in confining pressure, which created an increase in the modulus of the aggregate base, as well as an additional cover that reduced the stresses on the subgrade and created an increase in the modulus of the subgrade. The intensive FWD testing conducted on the pavement section also helped identify portions of the section susceptible to premature failure. These areas were subsequently rejected as locations for HVS test sections.In general, FWD testing indicated that areas of soft subgrade translated into areas of soft or low aggregate base modulus. The FWD testing also revealed the effect of asphalt concrete modulus on the behavior of the aggregate base. The data indicated that aggregate base modulus increased with asphalt concrete modulus.FWD testing also revealed the effect of temperature on the modulus of the asphalt concrete, which is typical of asphalt concrete layer and important for the interpretation of the performance of asphalt concrete mixes.The Heavy Vehicle Simulator (HVS) was used to test the asphalt concrete under conditions of accelerated loading. HVS test sites were selected within the constructed test section to evaluate their performance. The results were compared in terms of fatigue cracking, rutting, and surface deflections. Results indicate that the sections tested during the dry/warm season lasted longer than those tested during the wet/cold season.The performance of the sections seems to have been controlled by the behavior of the aggregate base. Elevated moisture contents in the aggregate base were recorded during the wet/cold months with corresponding FWD results which indicated high aggregate base modulus values for the same period. The results suggest that the modulus of the aggregate base is not a good indicator of performance.The results of the HVS test sections are being used to analyze the performance of asphalt concrete pavements and to develop performance models for pavement life prediction as defined in Research Goals 4.1, 4.5, and 4.7 in the PPRC Strategic Plan for 2003/2004

Summary of Construction Activities and Results from Six Initial Accelerated Pavement Tests Conducted on Asphalt Concrete Pavement Section for Modified-Binder Overlay

This report summarizes the activities and data collected during the construction of a pavement section used for investigating the performance of asphalt concrete pavements under accelerated pavement testing. This report also presents the preliminary results of six accelerated pavement tests conducted on the test section.The pavement section was constructed in September 2001 at the Pavement Research Center, located at the University of California Richmond Field Station. The construction was performed by a highway contractor with the purpose of simulating highway paving operations. Under these conditions, the results from the tests can be translated into predicting the behavior of actual in-service pavements.The pavement was composed of 90 mm of asphalt concrete, and 410 mm of recycled aggregate base on top of a prepared 200 mm subgrade. The layer thicknesses were designed according to Caltrans design procedures and checked using mechanistic methods to ensure limited rutting in the subgrade.Preparation and construction of the subgrade, aggregate base, and asphalt concrete were completed according to Caltrans practice. Compaction of the asphalt concrete was controlled based on the maximum theoretical density of the mix.Average in-situ relative densities for the subgrade and aggregate base were above 95 percent. Average air-void contents in the asphalt concrete layer were between 7 and 10 percent. Average thickness was 79 mm. Asphalt extractions from two samples indicated binder content by weight of aggregate of between 4.3 and 5.7 percent. The target binder content was 5.0 percent.Deflection testing conducted during the construction of the pavement section showed the effect of the asphalt concrete layer on the behavior of the aggregate base and subgrade layers. The asphalt concrete provided an increase in confining pressure, which created an increase in the modulus of the aggregate base, as well as an additional cover that reduced the stresses on the subgrade and created an increase in the modulus of the subgrade. The intensive FWD testing conducted on the pavement section also helped identify portions of the section susceptible to premature failure. These areas were subsequently rejected as locations for HVS test sections.In general, FWD testing indicated that areas of soft subgrade translated into areas of soft or low aggregate base modulus. The FWD testing also revealed the effect of asphalt concrete modulus on the behavior of the aggregate base. The data indicated that aggregate base modulus increased with asphalt concrete modulus.FWD testing also revealed the effect of temperature on the modulus of the asphalt concrete, which is typical of asphalt concrete layer and important for the interpretation of the performance of asphalt concrete mixes.The Heavy Vehicle Simulator (HVS) was used to test the asphalt concrete under conditions of accelerated loading. HVS test sites were selected within the constructed test section to evaluate their performance. The results were compared in terms of fatigue cracking, rutting, and surface deflections. Results indicate that the sections tested during the dry/warm season lasted longer than those tested during the wet/cold season.The performance of the sections seems to have been controlled by the behavior of the aggregate base. Elevated moisture contents in the aggregate base were recorded during the wet/cold months with corresponding FWD results which indicated high aggregate base modulus values for the same period. The results suggest that the modulus of the aggregate base is not a good indicator of performance.The results of the HVS test sections are being used to analyze the performance of asphalt concrete pavements and to develop performance models for pavement life prediction as defined in Research Goals 4.1, 4.5, and 4.7 in the PPRC Strategic Plan for 2003/2004

Summary of Construction Activities and Results from Six Initial Accelerated Pavement Tests Conducted on Asphalt Concrete Pavement Section for Modified-Binder Overlay

This report summarizes the activities and data collected during the construction of a pavement section used for investigating the performance of asphalt concrete pavements under accelerated pavement testing. This report also presents the preliminary results of six accelerated pavement tests conducted on the test section. The pavement section was constructed in September 2001 at the Pavement Research Center, located at the University of California Richmond Field Station. The construction was performed by a highway contractor with the purpose of simulating highway paving operations. Under these conditions, the results from the tests can be translated into predicting the behavior of actual in-service pavements. The pavement was composed of 90 mm of asphalt concrete, and 410 mm of recycled aggregate base on top of a prepared 200 mm subgrade. The layer thicknesses were designed according to Caltrans design procedures and checked using mechanistic methods to ensure limited rutting in the subgrade. Preparation and construction of the subgrade, aggregate base, and asphalt concrete were completed according to Caltrans practice. Compaction of the asphalt concrete was controlled based on the maximum theoretical density of the mix. Average in-situ relative densities for the subgrade and aggregate base were above 95 percent. Average air-void contents in the asphalt concrete layer were between 7 and 10 percent. Average thickness was 79 mm. Asphalt extractions from two samples indicated binder content by weight of aggregate of between 4.3 and 5.7 percent. The target binder content was 5.0 percent. Deflection testing conducted during the construction of the pavement section showed the effect of the asphalt concrete layer on the behavior of the aggregate base and subgrade layers. The asphalt concrete provided an increase in confining pressure, which created an increase in the modulus of the aggregate base, as well as an additional cover that reduced the stresses on the subgrade and created an increase in the modulus of the subgrade. The intensive FWD testing conducted on the pavement section also helped identify portions of the section susceptible to premature failure. These areas were subsequently rejected as locations for HVS test sections. In general, FWD testing indicated that areas of soft subgrade translated into areas of soft or low aggregate base modulus. The FWD testing also revealed the effect of asphalt concrete modulus on the behavior of the aggregate base. The data indicated that aggregate base modulus increased with asphalt concrete modulus. FWD testing also revealed the effect of temperature on the modulus of the asphalt concrete, which is typical of asphalt concrete layer and important for the interpretation of the performance of asphalt concrete mixes. The Heavy Vehicle Simulator (HVS) was used to test the asphalt concrete under conditions of accelerated loading. HVS test sites were selected within the constructed test section to evaluate their performance. The results were compared in terms of fatigue cracking, rutting, and surface deflections. Results indicate that the sections tested during the dry/warm season lasted longer than those tested during the wet/cold season. The performance of the sections seems to have been controlled by the behavior of the aggregate base. Elevated moisture contents in the aggregate base were recorded during the wet/cold months with corresponding FWD results which indicated high aggregate base modulus values for the same period. The results suggest that the modulus of the aggregate base is not a good indicator of performance. The results of the HVS test sections are being used to analyze the performance of asphalt concrete pavements and to develop performance models for pavement life prediction as defined in Research Goals 4.1, 4.5, and 4.7 in the PPRC Strategic Plan for 2003/2004.UCPRC-RR-2005-03, Civil Engineering

Reflective Cracking Study: Initial Construction, Phase 1 HVS Testing, and Overlay Construction

This first-level report describes the design and construction of a Heavy Vehicle Simulator (HVS) test track that will be used to validate Caltrans overlay strategies for the rehabilitation of cracked asphalt concrete. The report also summarizes the first phase of HVS testing, carried out on six separate sections to crack the pavement, as well as design and construction of the overlays for the reflective cracking HVS experiments. The construction, preliminary field and laboratory data, and accelerated pavement tests reveal several issues regarding the performance of the asphalt concrete pavement cross section tested under the Heavy Vehicle Simulator. The test track was constructed in September 2001. HVS testing took place between December 21, 2001, and March 25, 2003. Each section was trafficked with a 60 kN (13,500 lb) load using a bi-directional loading pattern with wander. Pavement temperature at 50 mm depth was maintained at 20°C (68°F) using a temperature control chamber. Findings from the HVS testing include: • Analysis of deflection measurements revealed that the modulus of the asphalt concrete was significantly affected by the asphalt concrete temperature. • The performance of the HVS test sections appeared to be significantly influenced by the behavior of the aggregate base. Sections that were tested during the dry months lasted longer both in fatigue and surface rutting than the sections tested during the wet months. • Air-void contents and thicknesses were similar for the test sections; therefore, the effect of these variables could not be addressed. • Deflection results could not be satisfactorily used as an indicator of aggregate base performance. Aggregate base moduli were higher during the cold/wet months but decreased rapidly when tested under the HVS. The aggregate base moduli of the sections during the dry/warm months were lower than those during the cold/wet months, but the sections tested during the dry period had longer pavement lives. Deflections determined with the RSD during HVS testing and an FWD after testing were used to determine overlay thicknesses. A full-thickness design of 90 mm (3.5 in) was selected for the AR4000-D control section and one of the modified binder mixes (MB-G). The remaining sections were designed as half-thickness (45 mm) (1.7 in). The overlays were placed on June 14, 2003

Reflective Cracking Study: Initial Construction, Phase 1 HVS Testing, and Overlay Construction

This first-level report describes the design and construction of a Heavy Vehicle Simulator (HVS) test track that will be used to validate Caltrans overlay strategies for the rehabilitation of cracked asphalt concrete. The report also summarizes the first phase of HVS testing, carried out on six separate sections to crack the pavement, as well as design and construction of the overlays for the reflective cracking HVS experiments. The construction, preliminary field and laboratory data, and accelerated pavement tests reveal several issues regarding the performance of the asphalt concrete pavement cross section tested under the Heavy Vehicle Simulator. The test track was constructed in September 2001. HVS testing took place between December 21, 2001, and March 25, 2003. Each section was trafficked with a 60 kN (13,500 lb) load using a bi-directional loading pattern with wander. Pavement temperature at 50 mm depth was maintained at 20°C (68°F) using a temperature control chamber. Findings from the HVS testing include: • Analysis of deflection measurements revealed that the modulus of the asphalt concrete was significantly affected by the asphalt concrete temperature. • The performance of the HVS test sections appeared to be significantly influenced by the behavior of the aggregate base. Sections that were tested during the dry months lasted longer both in fatigue and surface rutting than the sections tested during the wet months. • Air-void contents and thicknesses were similar for the test sections; therefore, the effect of these variables could not be addressed. • Deflection results could not be satisfactorily used as an indicator of aggregate base performance. Aggregate base moduli were higher during the cold/wet months but decreased rapidly when tested under the HVS. The aggregate base moduli of the sections during the dry/warm months were lower than those during the cold/wet months, but the sections tested during the dry period had longer pavement lives. Deflections determined with the RSD during HVS testing and an FWD after testing were used to determine overlay thicknesses. A full-thickness design of 90 mm (3.5 in) was selected for the AR4000-D control section and one of the modified binder mixes (MB-G). The remaining sections were designed as half-thickness (45 mm) (1.7 in). The overlays were placed on June 14, 2003.UCPRC-RR-2005-03, Civil Engineering