ABSTRACT
BACKGROUND AND AIMS: The coronavirus disease 2019 (COVID-19) pandemic is severely threatening and challenging public health worldwide. Epidemiological studies focused on the influence of outdoor air pollution (AP) on COVID-19 risk have produced inconsistent conclusions. We aimed to quantitatively explore this association using a meta-analysis. METHODS: We searched for studies related to outdoor AP and COVID-19 risk in the Embase, PubMed, and Web of Science databases. No language restriction was utilized. The search date entries were up to August 13, 2021. Pooled estimates and 95% confidence intervals (CIs) were obtained with random-/fixed-effects models. PROSPERO registration number: CRD42021244656. RESULTS: A total of 35 articles were eligible for the meta-analysis. For long-term exposure to AP, COVID-19 incidence was positively associated with 1 µg/m3 increase in nitrogen dioxide (NO2; effect size = 1.042, 95% CI 1.017-1.068), particulate matter with diameter <2.5 µm (PM2.5; effect size = 1.056, 95% CI 1.039-1.072), and sulfur dioxide (SO2; effect size = 1.071, 95% CI 1.002-1.145). The COVID-19 mortality was positively associated with 1 µg/m3 increase in nitrogen dioxide (NO2; effect size = 1.034, 95% CI 1.006-1.063), PM2.5 (effect size = 1.047, 95% CI 1.025-1.1071). For short-term exposure to air pollutants, COVID-19 incidence was positively associated with 1 unit increase in air quality index (effect size = 1.001, 95% CI 1.001-1.002), 1 µg/m3 increase NO2 (effect size = 1.014, 95% CI 1.011-1.016), particulate matter with diameter <10 µm (PM10; effect size = 1.005, 95% CI 1.003-1.008), PM2.5 (effect size = 1.003, 95% CI 1.002-1.004), and SO2 (effect size = 1.015, 95% CI 1.007-1.023). CONCLUSIONS: Outdoor air pollutants are detrimental factors to COVID-19 outcomes. Measurements beneficial to reducing pollutant levels might also reduce the burden of the pandemic.
Subject(s)
Air Pollution , COVID-19 , Air Pollution/adverse effects , Environmental Exposure/analysis , Humans , Particulate Matter/toxicity , SARS-CoV-2ABSTRACT
BACKGROUND: The confirmed coronavirus disease 2019 (COVID-19) cases, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have exceeded 21 million (with more than 775,000 fatalities), and the number of children with COVID-19 is also increasing. This study aimed to summarize the chest imaging characteristics of pediatric COVID-19 cases and provide a reference for the diagnosis and control of pediatric COVID-19. METHODS: The study protocol was registered in PROSPERO, number CRD42020177391. Studies related to pediatric COVID-19 imaging manifestations were accessed from PubMed, Web of Science, and the Cochrane library databases, without language limitations. The publication date was limited to April 1, 2020, and it was updated on May 1 and May 27, 2020. Data normalization was determined with the Freeman-Tukey double arcsine transformation. Summarized incidences with 95% confidence intervals of various imaging manifestations were assessed by random-effects models. Heterogeneity was assessed with meta-regression and subgroup analyses, robustness with sensitivity analyses; and publication biases with Egger's test. RESULTS: Twenty-three with 517 cases were included in this study. The summarized incidence of chest computed tomography abnormalities in pediatric COVID-19 cases was 70%, which was lower than what has been seen in adults. The incidence of halo signs in pediatric COVID-19 cases was 26%, which is rarely seen in adult COVID-19 cases. The incidences of ground-glass opacities (GGOs), GGOs and consolidations, consolidations, reverse halo signs, crazy paving signs, pleural effusion, bronchopneumonia-like signs, air bronchograms, and increased lung markings were 40%, 25%, 10%, 2%, 4%, 1%, 15%, 12%, and 31%, respectively. Pericardial effusions were found in the computed tomography images of adult COVID-19 cases but were scarcely seen in the computed tomography images of pediatric COVID-19 cases. The incidences of bilateral lesions, unilateral lesions, and peripheral lesions were 35%, 22%, and 26%, respectively. CONCLUSIONS: Chest computed tomography imaging of pediatric COVID-19 cases resulted in various abnormalities that were milder than those of adults. This study will hopefully provide a reference to help identify pediatric COVID-19 cases.