Related Experiment Video
Updated: Jan 9, 2026
05:46
A Novel Inhalation Mask System to Deliver High Concentrations of Nitric Oxide Gas in Spontaneously Breathing Subjects
Published on: May 4, 2021
5.7K
Association between nitrogen oxides and COVID-19 risk: A Mendelian randomization study
Jing Cao1, Haibo Xu, Zixiao Chen
1The First Department of Pulmonary and Critical Care Medicine, The Second Hospital of Hebei Medical University, Hebei Key Laboratory of Respiratory Critical Care Medicine, Hebei Institute of Respiratory Diseases, Shijiazhuang, Hebei, China.
Medicine
|December 2, 2025
Summary
Air pollution, specifically nitrogen oxides (NOx) and nitrogen dioxide (NO2), may causally increase the risk of COVID-19 hospitalization. Controlling air pollution could help mitigate severe COVID-19 progression.
Area of Science:
- Environmental Epidemiology
- Public Health
- Genetics
Background:
- Cross-sectional studies suggest a link between nitrogen oxides (NOx) and COVID-19 severity.
- Previous research has not utilized Mendelian randomization (MR) to establish causality.
Purpose of the Study:
- To investigate the potential causal association between nitrogen oxides (NOx) exposure and the risk of coronavirus disease 2019 (COVID-19).
- To differentiate the impact of NOx and nitrogen dioxide (NO2) on COVID-19 risk using genetic data.
Main Methods:
- Two-sample Mendelian randomization (MR) analysis using integrated UK Biobank and IEU GWAS data.
- Employed inverse-variance weighting and robust adjusted profile score methods.
- Utilized scatter plots, funnel plots, and leave-one-out analysis for validation.
Main Results:
- MR identified a significant association between NOx air pollution and COVID-19 hospitalization (OR=3.76, P=0.0166).
- Nitrogen dioxide (NO2) air pollution also showed a significant association with COVID-19 hospitalization (OR=2.95, P=0.0326).
- No significant association was found between NO2/NOx exposure and very severe respiratory confirmed COVID-19.
Conclusions:
- Mendelian randomization analysis suggests a potential causal link between NO2 and NOx exposure and increased COVID-19 risk.
- Reducing air pollution may be a strategy to slow the progression and prevent adverse outcomes of COVID-19.
More Related Videos
Related Concept Videos
01:29Bias in Epidemiological Studies
1.2K
Biases can arise at various stages of research, from study design and data collection to analysis and interpretation. Recognizing and addressing these biases is essential to ensure the validity and reliability of epidemiological findings.Broadly speaking, biases in epidemiology fall into three main categories: selection bias, information bias, and confounding. A more detailed description of possible biases is:
1.2K
01:27Confounding in Epidemiological Studies
555
Confounding in statistical epidemiology represents a pivotal challenge, referring to the distortion in the perceived relationship between an exposure and an outcome due to the presence of a third variable, known as a confounder. This variable is associated with both the exposure and the outcome but is not a direct link in their causal chain. Its presence can lead to erroneous interpretations of the exposure's effect, either exaggerating or underestimating the true association. This...
555
01:05Single Nucleotide Polymorphisms-SNPs
17.9K
A single nucleotide polymorphism or SNP is a single nucleotide variation at a specific genomic position in a large population. It is the most prevalent type of sequence variation found in the human genome. Point mutations that occur in more than 1% of the population qualify as SNPs. These are present once every 1000 nucleotides on an average in the human genome. Replacement of a purine with another purine (A/G) or a pyrimidine with another pyrimidine (C/T) is known as a transition. In contrast,...
17.9K
01:09Odds Ratio
1.5K
The odds ratio (OR) is a statistical measure used extensively in epidemiology and research to quantify the strength of association between exposure and outcome across different groups. Unlike relative risk, which compares the probabilities of an event occurring, the odds ratio compares the odds of an event occurring in the exposed group to the odds of it occurring in the unexposed group. The odds, in this context, are calculated as the probability of the event happening divided by the...
1.5K
01:12Relative Risk
1.8K
Relative risk (RR) is a statistical measure commonly used in epidemiology to compare the likelihood of a particular event occurring between two groups. This metric is important for evaluating the relationship between exposure to a specific risk factor and the probability of a particular outcome. It plays a crucial role in medical research, public health studies, and risk assessment. Relative risk quantifies how much more (or less) likely an event is to occur in an exposed group compared to an...
1.8K
01:21Causality in Epidemiology
1.5K
Causality or causation is a fundamental concept in epidemiology, vital for understanding the relationships between various factors and health outcomes. Despite its importance, there's no single, universally accepted definition of causality within the discipline. Drawing from a systematic review, causality in epidemiology encompasses several definitions, including production, necessary and sufficient, sufficient-component, counterfactual, and probabilistic models. Each has its strengths and...
1.5K