Asthma/COPD Overlap: A Gene by Environment Interaction?

Asthma, chronic obstructive pulmonary disease, and asthma-COPD overlap among US working adults

BACKGROUND

Asthma-COPD overlap (ACO) is a respiratory condition with more severe respiratory symptoms, poorer quality of life, and increased hospital admissions compared with asthma or COPD alone.

OBJECTIVES

Estimate asthma, chronic obstructive pulmonary disease (COPD), and ACO prevalence among workers by industry and occupation and assess physical and mental health status, healthcare utilization, among workers with ACO.

METHODS

The 2014-2018 National Health Interview Survey (NHIS) data for working adults aged ≥18 years employed (sample n = 99,424) in the 12 months prior to the survey were analyzed. Age-adjusted ACO, COPD and asthma prevalence and prevalence ratios adjusted for age, sex, race and smoking status were estimated.

RESULTS

During 2014-2018, of the estimated 166 million (annual average) US workers, age-adjusted asthma, COPD, and ACO prevalence was 6.9%, 4.0%, and 1.1%, respectively. ACO prevalence was highest among workers aged ≥65 years (2.0%), females (1.6%), current smokers (1.9%), those living below the federal poverty level (2.3%), and workers in the accommodation and food services (1.6%) industry and personal care and service (2.3%) occupations. Workers with ACO had more frequent (p < 0.05) physician office visits, emergency department visits; and were more likely to be in poorer mental health, obese, have more lost workdays, more bed days, and comorbidities compared to workers with asthma alone and workers with COPD alone.Conclusion: Higher ACO prevalence among worker groups and increased healthcare utilization underscores the need for early identification of asthma and COPD, assessment of potential workplace exposures, and implementation of tailored interventions to reduce ACO among working adults.

Exome variants associated with asthma and allergy

The mutational spectrum of asthma and allergy associated genes is not known although recent biobank based exome sequencing studies included these traits. We therefore conducted a secondary analysis of exome data from 281,104 UK Biobank samples for association of mostly rare variants with asthma, allergic rhinitis and atopic dermatitis. Variants of interest (VOI) were tabulated, shared genes annotated and compared to earlier genome-wide SNP association studies (GWAS), whole genome sequencing, exome and bisulfit sequencing studies. 354 VOI were significantly associated with asthma, allergic rhinitis and atopic dermatitis. They cluster mainly in two large regions on chromosome 6 and 17. After exclusion of the variants associated with atopic dermatitis and redundant variants, 321 unique VOI remain in 122 unique genes. 30 genes are shared among the 87 genes with increased and the 65 genes with decreased risk for allergic disease. 85% of genes identified earlier by common GWAS SNPs are not replicated here. Most identified genes are located in interferon ɣ and IL33 signaling pathway. These genes include already known but also new pharmacological targets, including the IL33 receptor ST2/IL1RL1, as well as TLR1, ALOX15, GSDMA, BTNL2, IL13 and IKZF3. Future pharmacological studies will need to included these VOI for stratification of the study population paving the way to individualized treatment.

Interaction of Interleukin 7 Receptor (IL7R) and IL6 Gene Polymorphisms with Smoking Associated with Susceptibility to Asthma in Chinese Han Adults

BACKGROUND

the aim of this study was to investigate the relationship between the risk of asthma and multiple single nucleotide polymorphisms (SNPs) in interleukin 7 receptor (IL7R) and IL6 genes, as well as the gene- environment interactions.

METHODS

This is a hospital- based case- control study. A total of 430 patients with asthma were continuously recruited. Four SNPs within IL7R and IL6 gene were genotyped by PCR based restriction fragment length polymorphism. The Hardy- Weinberg balance of all participants was tested by SNPstats. The best interaction combination of four SNPs in IL7R and IL6 genes and smoking was screened by generalized multifactor dimensionality reduction (GMDR). Logistic regression was used to test the association between four SNPs and asthma, and stratified analysis for rs1800795 gene-smoking interaction, synergy index (SI) was calculated.

RESULTS

The rs1494558-G and rs1800795-C were associated with an increased risk of asthma, adjusted ORs (95% CI) was 1.81 (1.29-2.42) and 1.75 (1.20-2.28), respectively. GMDR indicated that the test accuracy for two-locus model involving rs1800795 and smoking was 0.5721, and the p = .011, the results providing evidence for rs1800795 gene-smoking interaction. The asthma risk was higher in smokers with GC or CC genotype than the sum of risks in subjects with smoking or GC or CC genotype alone, compared to the never smokers with GG genotype, the OR (95%CI) was 4.97 (3.01-7.24), and the synergy index (SI) was 1.68 (1.08-2.60).

CONCLUSIONS

The rs1494558-G and rs1800795-C alleles, gene- environment interaction between rs1800795 and smoking were all associated with increased asthma risk.

Indoor mold odor in the workplace increases the risk of Asthma-COPD Overlap Syndrome: a population-based incident case-control study

Background

Previous studies have suggested an increased risk of asthma related to indoor dampness problems, but their role in the etiology of Asthma-COPD Overlap Syndrome has not been studied. We utilized a population-based incident case–control study to assess potential effect of indoor dampness and molds at home and at work on development of ACOS.

Methods

We recruited systematically all new cases of asthma diagnosed during a 2.5-year study period (1997–2000) and randomly selected controls from the source population of adults 21–63 years old and representing 500,000 persons-years in the Pirkanmaa Hospital District, South Finland. Exposure indicators included water damage, damp stains or paint peeling, visible mold, and mold odor, asked separately for home and workplace. The clinically diagnosed case series consisted of 521 adults with newly diagnosed asthma. Altogether 25 of them satisfied the criteria for ACOS-cases, i.e. FEV1/FVC < 0.70 in post-bronchodilator spirometry. The control series, including 932 controls, were from a random sample of source population, after excluding 76 (7.5%) controls with asthma.

Results

In logistic regression analysis adjusting for confounders, the risk of ACOS was significantly related to presence of mold odor in the workplace (OR 3.43; 95% CI 1.04–11.29), but not to other dampness indicators. The fraction of ACOS attributable to workplace mold odor was 70.8% (95% CI 3.8–91.1%) among the exposed. The risk of ACOS was not related to mold exposures at home.

Conclusions

Present results provide new evidence of the significant relation between workplace exposure to mold odor and adult-onset ACOS.