Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Globalization, Food Security, Public Health & Prosperity Focus on India

Non

History of the Australian breast device registry

Following the Dow Corning crisis in the 1990s, several national breast implant registries were formed by plastic surgery societies around the world. The Australian Breast Implant Registry (BIR) was developed in 1997 as a voluntary registry where patients were charged a moiety per implant. At the time of the Poly Implant Prothèse (PIP) crisis in 2010, there were over 30,000 registrations in the BIR. However, when the dataset was interrogated to retrieve PIP implant-related information, only 3.4 per cent of 13,000 PIP implants were recorded in the BIR database

Optical dispersion of homogeneously mixed ZnS-MgF<SUB>2</SUB> films

Mixed films of ZnS-MgF2 were prepared by co-evaporation from a single source. The dispersion of the optical constants was obtained from the reflectance and transmittance data of the films for various compositions in the spectral range 2000-7000 &#197;. The values of the optical constants of the mixed films at any wavelength lie between the values of the optical constants of pure ZnS and MgF2 films. The refractive index of the mixed films closely obeys the Lorentz-Lorenz relation at wavelengths at which the absorption is small. The fundamental absorption edge of the mixed films shifts from that of MgF2 to that of ZnS continuously but non-linearly on increasing the concentration of ZnS in MgF2. Thus it is possible to use these films as variable frequency cut-off filters. The fundamental absorption edge of the mixed films follows the (hv-Eg)2 relation, indicating an indirect optical transition, in sharp contrast to the direct optical transition observed in bulk ZnS

Equivalent refractive index of multilayer films of different materials

The variation of the equivalent refractive index with composition of multilayer films of ZnS-MgF2-SiO, ZnS-Na3AlF6 and Ge-ZnS, prepared by depositing alternate layers of different materials, has been investigated. It has been established that, for small step thicknesses (much less than the wavelength of light to be used for measurements) of each layer, the composite multilayer films are optically equivalent to homogeneously mixed films of the same materials of corresponding relative compositions. Further, the results show that the indices of the multilayer films of ZnS-MgF2-SiO and ZnS-Na3AlF6 are in good agreement with the values predicted on the basis of the Lorentz-Lorenz theory. The refractive index of Ge-ZnS multilayer films is in agreement with the Drude theory. Our studies also show that the refractive index of a multilayer film composed of three materials, two of which react chemically in the molten and vapour states, as, for example, ZnS and SiO in ZnS-MgF2-SiO films, is equivalent to that expected theoretically for a homogeneously mixed film of the same materials. The controlled and predictable equivalent behaviour of multilayer films suggests their use to produce variable refractive index optical coatings by selecting any number of materials which may or may not react with each other chemically

Optical behaviour of gradient-index multilayer films

Gradient-index films (i.e. films in which the refractive index varies continuously along the normal to the film surface) have been prepared by depositing alternate layers of two materials of different refractive indices. The optical behaviour of gradient-index films of the ZnS-MgF2 combination has been investigated. The results show that, for small step thicknesses (much less than the wavelength of light used for the measurements) of each layer, a gradient-index multilayer film behaves like an inhomogeneous film. A periodically stratified medium obtained by depositing a number of identical gradient-index ZnS-MgF2 multilayer films behaves like a band reflecting filter. The band reflectance increases with the number of periods and tends to nearly 100% for 20 periods. Further, the reflectance band is observed to shift towards longer wavelengths on increasing the step thicknesses of the layers in the periods. The reflectivity of the stratified medium has been calculated theoretically by assuming that the gradient-index film is made of a stack of homogeneous films. The experimental and theoretical results are compared and discussed

Validation of Grobman’s graphical nomogram for prediction of vaginal delivery in Indian women with previous caesarean section

Purpose: To validate Grobman’s nomogram for prediction of trial of labour after caesarean section (TOLAC) success in the Indian population. Methods: A prospective observational study of women with previous lower segment caesarean sections (LSCS) who were admitted for TOLAC between January 2019 and June 2020 at a tertiary care hospital We compared the Grobman’s predicted VBAC success probability to the observed VBAC rate in the study population and devised a receiver-operator characteristics (ROC) curve for the nomogram. Results: Among the 124 women with prior LSCS who chose TOLAC and were included in the study, 68 (54.8%) had a successful VBAC and 56 (45.2%) had a failed TOLAC. The mean Grobman’s predicted success probability for the cohort was 76.7%, significantly higher in VBAC women versus CS women (80.6% vs. 72.1%; p 0.001). The VBAC rate was 69.1% with a predicted probability of > 75% and only 42.9% with a probability of 50%. Women in the > 75% probability group had a nearly similar observed and predicted VBAC rate (69.1% vs. 86.3%; p = 0.002), and a greater number of women in the 50% probability group had successful VBAC than predicted (42.9% vs. 39.5%; p = 0.018). The area under the ROC curve for the study was 0.703 (95% CI 0.609–0.797; p 0.001). Grobman’s nomogram had a sensitivity of 57.35%, a specificity of 82.14%, a positive predictive value (PPV) of 79.59%, and a negative predictive value (NPV) of 61.33% at a predicted probability cut-off of 82.5%. Conclusions: Women who had a higher Grobman’s predicted probability had greater VBAC success rates than those with low predicted probability scores. The prediction ability of the nomogram was highly accurate at higher predicted probabilities, and even at lower predicted probabilities, women did have good odds of delivering vaginally