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

The Prevalence of Adhd in Primary School Students in Tehran

Background:Attention Deficit Hyperactivity Disorder (ADHD) is characterized by a developmental disorder involving inappropriate poor attention span or age-inappropriate features of hyperactivity and impulsivity and/or both.Methods:In order to assess the prevalence of children with ADHD in Tehran,a sample of 2667 children including both boys & girls aged between 7-12 years were selected by a 2-stage method sampling among a grid of sectors of 19 different educational areas by stratified random sampling.We tested the rate of ADHD in the considered children based on two questionnaires of Conners Parent and Teacher Rating Scales (CPRS and CTRS) and semi-structured interviews.Results:According to the recent studies,it is possible to describe the rate of ADHD prevalence based on the CPRS and CTRS questionnaires and semistructured interview among the primary school children in Tehran (aged between 7- 12 years of age) with a range of 3%to 6%.Conclusion:These mentioned findings are somewhat similar to the announced statistics of the American Psychiatric Association (APA)(2003)

The Prevalence Of Adhd In Primary School Students In Tehran

Background: Attention Deficit Hyperactivity Disorder (ADHD) is characterized by a developmental disorder involving inappropriate poor attention span or age-inappropriate features of hyperactivity and impulsivity and/or both. Methods: In order to assess the prevalence of children with ADHD in Tehran, a sample of 2667 children including both boys & girls aged between 7-12 years were selected by a 2-stage method sampling among a grid of sectors of 19 different educational areas by stratified random sampling. We tested the rate of ADHD in the considered children based on two questionnaires of Conners Parent and Teacher Rating Scales (CPRS and CTRS) and semi-structured interviews. Results: According to the recent studies, it is possible to describe the rate of ADHD prevalence based on the CPRS and CTRS questionnaires and semi-structured interview among the primary school children in Tehran (aged between 712 years of age) with a range of 3% to 6%. Conclusion: These mentioned findings are somewhat similar to the announced statistics of the American Psychiatric Association (APA) (2003)

Epidemiology of hepatitis B in pregnant Iranian women: a systematic review and meta-analysis

Perinatal transmission is one of the most common routes of hepatitis B virus (HBV) transmission. This study aims to identify the epidemiological features of HBV among pregnant Iranian women. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Two authors independently searched several online databases without time limit until May 2017. The databases include Magiran, Iranmedex, SID, Medlib, IranDoc, Scopus, PubMed, Science Direct, Cochrane, Web of Science and Google Scholar. The data were analyzed based on a random-effects model using Comprehensive Meta-Analysis software version 2. Thirty-seven studies were included in the meta-analysis. The prevalence of HBV among pregnant Iranian women was 1.18 (95 CI: 0.09-1.53). The prevalence of HBV among pregnant women living in urban and rural areas was 1.60 (95 CI: 0.06-4.30) and 1.70 (95 CI: 0.09-3.2), respectively. The prevalence of HBV among housewives and working pregnant women was 4.3 (95 CI: 1.4-12.5) and 1.2 (95 CI: 0.02-5.8), respectively. The risk of developing an HBV infection was significantly associated with illiteracy (p = 0.013), abortion (p = 0.001), blood transfusion (p < 0.001) and addicted spouse (p = 0.045). However, no significant relationship was observed between HBV infection and urbanization (p = 0.65), occupation (p = 0.37), history of surgery (p = 0.32) or tattooing (p = 0.69). Vaccination coverage (receiving at least a single dose) in pregnant women was 9.8 (95 CI: 5.3-17.5). The prevalence of HBV among pregnant women is lower than in the general population of Iran. HBV vaccination coverage was low among pregnant Iranian women. Therefore, health policy-makers are recommended to enforce immunization programs for HBV vaccination among high-risk pregnant women