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

Notas para una historia de las ciencias agropecuarias en Colombia

Este ensayo analiza la introducción de nuevas formas de utilización de los suelos y cambios que se han operado en los cultivos y en la cría y levante de ganadería remontándose al siglo XVIII. Sostiene que la primera Revolución Agrícola nada debe a la ciencia y muy poco a la invención mecánica. Hace referencia al desarrollo de la Rev~lución Agrícola operada en algunos países europeos y en los Estados Unidos de Norteamérica, destacando su forma vertiginosa. Señala la significativa participación que tuvieron las publicaciones, en la transmisión del conocimiento científico y las innovaciones en las técnicas agropecuarias. Manifiesta la notable diferencia existente entre la primera y la segunda Revolución Agrícola, pues la primera se concretó a los procedimientos y la segunda estudió la aplicación de la ciencia a la agricultura, buscando mejorar la producción por medio de la química aplicada al estudio de los fertilizantes y al valor nutritivo de los forrajes. No omite en el análisis histórico el encomiable esfuerzo hecho para construir maquinaria destinada al cultivo y recolección de las cosechas, que transformaron los procedimientos existentes en la agricultura y el empleo de vacunas para prevenir las enfermedades de origen microbiano. Alude a la contribución y progreso que tanto la parasitología como la fisiología tuvieron en los avances obtenidos para mejorar el sistema agropecuario. Respecto al desenvolvimiento que las ciencias agropecuarias han tenido en Colombia, indica et atraS{) técnico en que se encontraba la agricultura de la Nueva Granada en la épocp colonial y en todo el siglo XIX. El notable movimiento científico iniciado con la Expedición Botánica se interrumpió abruptamente con la guerra de independencia. Sobre las iniciativas e intereses posteriores al evento de la independencia, se hace referencia a la contratación que, Don Francisco Antonio Zea, en el gobierno progresista del General Santander, hizo de eminentes científicos en las áreas de zoología, entomología, química y agronomía, para que se encargaran de desarrollar en el país las ciencias de su especialización para ser utilizadas en el campo agrícola. Al continuar con la exposición de los esfuerzos encaminados a difundir los conocimientos útiles, se refiere al papel cumplido por algunas publicaciones de contenido técnico, así como al énfasis que se hizo para el establecimiento de estaciones y granjas experimentales y la orientación que se le dió tanto a la educación secundaria como superior para incrementar y desarrollar esta actividad. El estudio forma parte de los trabajos realizados dentro del proyecto sobre ''Historia Social de la Ciencia en Colombia·· adelantado por la Sociedad Colombiana de Epistemología con la financiación de COLCIENCIAS y del Programa de Desarrollo Científico y Tecnológico de la OEA

Exercise treatments for chronic low back pain: a network meta-analysis

Objectives: This is a protocol for a Cochrane Review (intervention). The objectives are as follows:. The objectives of this systematic review, conducted using a collaborative review model, are to:. Assess the effectiveness of exercise treatment (overall) in adults with chronic non-specific low back pain on important individual health outcomes: pain, functional limitations, health-related quality of life, depression, and adverse effects versus comparison treatments: (a) placebo, sham, or attention control, (b) no trial treatment (including waiting lists, control groups described as having no treatment provided, usual/normal care not controlled by the trial available to all treatment groups, or when the exercise and comparison groups receive the same co-interventions, allowing the effect of exercise treatment to be isolated), and (c) other conservative treatments (eight categories). Estimate the treatment effects and associated uncertainty for comparisons of different specific types of exercise treatment in adults with chronic non-specific low back pain to each other, and to each comparison treatment, using direct and indirect evidence with network meta-analysis. Estimate the treatment effects and associated uncertainty for comparisons of treatments composed of different exercise type categories, design, delivery, dose, and additional treatment components, and their combinations, using direct and indirect evidence with component network meta-analysis