Daily Respiratory Research Analysis
Three impactful respiratory studies advance public health and mechanistic understanding. A US-wide multi-cohort analysis links PM2.5, NO2, and ozone to higher childhood asthma incidence with clear sociodemographic disparities. A massive genomic cohort clarifies that most CFTR heterozygotes do not have substantially elevated CF-related disease risks, while a Thorax meta-analysis quantifies inhalational exposures that increase interstitial lung disease risk.
Summary
Three impactful respiratory studies advance public health and mechanistic understanding. A US-wide multi-cohort analysis links PM2.5, NO2, and ozone to higher childhood asthma incidence with clear sociodemographic disparities. A massive genomic cohort clarifies that most CFTR heterozygotes do not have substantially elevated CF-related disease risks, while a Thorax meta-analysis quantifies inhalational exposures that increase interstitial lung disease risk.
Research Themes
- Air pollution and childhood asthma disparities
- Genetic risk profiling of CFTR heterozygotes
- Occupational/environmental inhalational exposures and ILD risk
Selected Articles
1. Disparities in the association of ambient air pollution with childhood asthma incidence in the ECHO consortium: A US-wide multi-cohort study.
In 23,234 US children followed to age 10 across 34 ECHO sites, higher prior-year PM2.5, NO2, and ozone exposures were associated with increased asthma incidence. Effects varied by sociodemographic context, underscoring structural vulnerability and environmental injustice.
Impact: This large, diverse multi-cohort provides robust, time-varying evidence that common pollutants raise childhood asthma risk and identifies disparity modifiers, pointing to actionable policy levers.
Clinical Implications: Pediatric and public health strategies should integrate pollution reduction with targeted interventions in high-vulnerability communities (e.g., housing, traffic mitigation, green space). Clinicians can use exposure-aware risk counseling and advocate for environmental health policies.
Key Findings
- Each IQR increase in prior-year PM2.5, NO2, and ozone was associated with higher asthma incidence by age 10 (HR ~1.11–1.19).
- Time-varying Cox models accounting for site and socio-demographics demonstrated effect modification by social disadvantage.
- Residential history-based exposure assignment enabled longitudinal linkage across 182,008 person-years.
Methodological Strengths
- Large, geographically diverse multi-cohort with 23,234 children and 182,008 person-years.
- Time-varying exposure modeling with residential histories and adjustment for area- and individual-level covariates.
Limitations
- Modeled exposures and potential exposure misclassification.
- Heterogeneity in exposure time windows (e.g., differing years for NO2 and ozone) and residual confounding.
Future Directions: Quantify co-exposure mixtures, integrate personal/indoor exposures, and evaluate structural interventions (e.g., diesel restrictions) in vulnerable communities with quasi-experimental designs.
BACKGROUND: Characterization of US sociodemographic disparities in air pollution respiratory effects has often been limited by lack of participant diversity, geography, exposure characterization, and small sample size. METHODS: We included 34 sites comprising 23,234 children (born 1981-2021) from the Environmental influences on Child Health Outcomes (ECHO) Program with data on asthma diagnosis until age 10 (182,008 person-years). Predicted annual exposure to fine particulate matter (1988-2021), nitrogen dioxide (2000-2016), and ground ozone (2000-2016) were assigned based on residential histories. For each pollutant, we fitted time-varying Cox models adjusted for time trend, site, and several area- and individual-level sociodemographic features that were separately considered as modifiers via an interaction with exposure. RESULTS: The hazard ratio of incident asthma by age 10 years was 1.19 (95% CI = 1.10, 1.28), 1.19 (95% CI = 1.05, 1.34), and 1.11 (95% CI = 1.01, 1.22) of an interquartile range increase in prior-year exposure to fine particulate matter (6.17 µg/m CONCLUSIONS: US efforts to mitigate childhood asthma risk by reducing air pollution would benefit from addressing root structural causes of vulnerability and susceptibility, including spatial patterning in air pollution sources and exposures as well as social and economic disadvantage.
2. Diseases Common in Persons With Cystic Fibrosis Among CFTR Heterozygotes.
In 317,964 adults with WGS-linked EHRs, 7,957 CFTR heterozygotes showed no phenome-wide excess disease risk. Modest increases in select respiratory outcomes (e.g., ABPA, bronchiectasis, COPD) were observed, with effect sizes far lower than in CF homozygotes.
Impact: Clarifies real-world risk for a very large, diverse population of CFTR carriers, informing genetic counseling and respiratory surveillance without overmedicalization.
Clinical Implications: Routine screening for CF-related disease in CFTR heterozygotes is not broadly indicated; however, targeted evaluation is reasonable for carriers with recurrent respiratory infections, bronchiectasis, or ABPA features.
Key Findings
- Across 2,909 phenotypes, no significant phenome-wide associations were found in CFTR heterozygotes.
- Select respiratory risks showed modest ORs: ABPA 2.50, bronchiectasis 1.21, pneumococcal pneumonia 1.54, COPD 1.14, asthma 1.08, Pseudomonas infection 1.34.
- Diverse ancestry with mean 12.4-year follow-up supports generalizability of findings.
Methodological Strengths
- Phenome-wide association with whole-genome sequencing and long EHR follow-up.
- Diverse ancestry inference using 1000 Genomes and HGDP references.
Limitations
- EHR-based diagnoses may introduce misclassification.
- Limited power for rare outcomes within ancestry strata; residual confounding possible.
Future Directions: Dissect modifiers of elevated respiratory risk among subgroups (e.g., environmental exposures, polygenic background), and evaluate targeted surveillance strategies.
IMPORTANCE: Cystic fibrosis is one of the most commonly diagnosed autosomal recessive disorders in the US. It is estimated that more than 10 million individuals are heterozygous for a pathogenic CFTR gene variant in the US (heterozygotes). The phenotypic risk of these heterozygotes is not well defined, particularly among populations of predominantly non-European genetic ancestry. Understanding disease risk across each population can improve management strategies for all. OBJECTIVE: To examine associations of diseases across the phenome with CFTR heterozygotes. DESIGN, SETTING, AND PARTICIPANTS: The All of Us Research Program is a US-based ongoing longitudinal cohort study whose enrollment started nationally in 2018. In this genetic association study, whole-genome sequencing data were linked to electronic health records (EHRs) and surveys. Participants were 18 years and older. Similarity to genetic ancestral groups was genetically inferred using All of Us data and 2 large reference datasets, the 1000 Genomes Project and Human Genome Diversity Project. This analysis was conducted between February and April 2025. EXPOSURES: A single pathogenic CFTR variant. MAIN OUTCOMES AND MEASURES: The main variables included clinical diagnoses documented in EHRs. Multivariable-adjusted phenome-wide association studies were performed. The main measures were odds ratios (ORs), indicating risk for a particular disease or condition. RESULTS: Overall, 363 pathogenic variants were identified in the cohort. Among 317 964 adult participants (55.7% female; mean [SD] last age in EHR, 56.1 [16.9] years), 7957 heterozygotes and 280 995 noncarriers were identified. Participants were followed up through EHRs with a mean (SD) follow-up of 12.4 (9.0) years. The genetically inferred ancestral distribution of the cohort was 18.0% African, 16.2% American or Admixed American, 2.1% East Asian, 53.4% European, 0.3% South Asian, and 0.4% West Asian. Frequencies of heterozygotes varied by groups of genetic similarity to reference populations: 3.62% in participants most genetically similar to a European reference population (n = 169 812), 1.35% in participants most genetically similar to an African reference population (n = 57 297), and 1.86% in participants most genetically similar to an Admixed American reference population (n = 51 483). A total of 2909 phenotypes were analyzed. No statistically significant associations were identified in heterozygotes of all populations combined or within each genetic ancestral group. Among 52 cystic fibrosis-associated diseases, although an elevated risk of respiratory diseases and infections was observed in some heterozygotes (allergic bronchopulmonary aspergillosis [OR, 2.50; 95% CI, 1.27-4.95]; bronchiectasis [OR, 1.21; 95% CI, 1.00-1.47]; pneumonia due to Streptococcus pneumoniae [OR, 1.54; 95% CI, 1.05-2.26]; chronic obstructive pulmonary disease [OR, 1.14; 95% CI, 1.05-1.24]; asthma [OR, 1.08; 95% CI, 1.01-1.15]; and Pseudomonas infection [OR, 1.34; 95% CI, 1.03-1.74]), effect sizes of these associations were several orders of magnitude lower than those found in homozygotes or predicted compound heterozygotes. CONCLUSIONS AND RELEVANCE: In this genetic association study, most heterozygotes did not appear to have a substantially higher risk of cystic fibrosis-associated diseases during their adulthood compared to noncarriers. Additional studies are needed to investigate the underlying factors for the elevated risk of respiratory and infectious diseases in some heterozygotes.
3. Inhalational exposures associated with risk of interstitial lung disease: a systematic review and meta-analysis.
Pooling 54 studies (over 40 million subjects), smoking, organic agents, metals, dust, and asbestos were each associated with higher ILD risk. Silica and fumes showed positive trends. The analysis excluded HP, pneumoconiosis, and sarcoidosis to focus on non-classical ILD risk.
Impact: Provides quantitative evidence to inform exposure histories, workplace protections, and preventive policies beyond classical occupational ILDs.
Clinical Implications: Clinicians should routinely elicit and document inhalational exposure histories (metals, organic agents, dusts, asbestos) and integrate exposure mitigation and surveillance for at-risk workers.
Key Findings
- Smoking (OR 1.69), organic exposures (OR 1.56), metals (OR 1.52), dust (OR 1.45), and asbestos (OR 1.53) increased ILD risk.
- Silica and fumes had positive associations trending toward significance.
- Excluded HP, pneumoconiosis, and sarcoidosis to isolate non-classical ILD risks.
Methodological Strengths
- Comprehensive search with dual independent review and data extraction.
- Multilevel random-effects meta-analysis across very large aggregated populations.
Limitations
- Exposure assessment heterogeneity and potential residual confounding.
- Observational evidence limits causal inference; publication bias possible.
Future Directions: Identify and quantify emerging occupational exposures, evaluate gene–environment interactions, and test targeted workplace interventions.
RATIONALE: Inhalational exposures are associated with risk of developing interstitial lung disease (ILD), yet the relationship between specific exposures and ILD is poorly characterised. OBJECTIVE: Identify inhalational exposures associated with ILD and estimate the effects of exposures on ILD risk. METHODS: MEDLINE and EMBASE databases were searched from 1990 to 2022 to identify inhalational exposures associated with ILD diagnosis. ILDs where causality is well-established (hypersensitivity pneumonitis, pneumoconiosis) and sarcoidosis were excluded. Two independent reviewers screened abstracts with full-text review and data extraction of eligible studies. Where possible, data were pooled and multilevel meta-analysis was specified using a random effects model. Sources of heterogeneity and risk of bias were assessed. MAIN RESULTS: 96 studies were included in the systematic review, representing 40 819 116 subjects (295 167 had ILD, 40 523 949 controls). For the meta-analysis, 54 studies were included (40 490 793 subjects: 273 899 ILD, 40 216 894 controls). Exposures associated with significantly increased ILD risk included smoking (OR 1.69, 95% CI 1.47 to 1.94), organic exposures (OR 1.56, 95% CI 1.12 to 2.16), metals (OR 1.52, 95% CI 1.07 to 2.16), dust (OR 1.45, 95% CI 1.20 to 1.76) and asbestos (OR 1.53, 95% CI 1.08 to 2.15). Silica and fumes had positive associations with ILD that trended towards significance. CONCLUSIONS: This systematic review and multilevel meta-analysis is the first to comprehensively assess the effect of inhalational exposures on overall risk of ILD, with multiple putative exposures identified. Future work should investigate novel occupational exposures associated with ILD, characterise the gene-environment interaction and develop preventative strategies. PROSPERO REGISTRATION NUMBER: CRD42022292908.