Occupation and adult-onset asthma among Chinese women in a population-based cohort

Association Between Organic Dust Exposure and Adult-Asthma: A Systematic Review and Meta-Analysis of Case-Control Studies

Background

Exposure to organic dust has been widely investigated as a potential risk factor for asthma with different results. To clarify a potential relationship, we performed the present meta-analysis to integrate the results of studies examining the association of organic dust exposure with asthma.

Methods

A comprehensive literature search in the electronic databases including EMBASE, PubMed and Cochrane Library databases (up to August 2018) was conducted. The adjusted odds ratios (ORs) with corresponding 95% confidence interval (CI) for organic dust exposure and asthma were retrieved and pooled to generate summary effect estimates in Revman 5.2.

Results

Database searches retrieved 1,016 records. A total of 17 studies containing 3,619 cases and 6,585 controls were finally included in our meta-analysis. The summary estimates suggested that organic dust exposure was positively associated with asthma (OR, 1.48; 95% CI, 1.26–1.75; P < 0.00001), whether among population-based case-control studies (OR, 1.24; 95% CI, 1.13–1.35; P < 0.00001) or hospital-based case-control studies (OR, 2.79; 95% CI, 1.27–6.12; P = 0.01). Subgroup analysis showed that paper/wood (OR, 1.62; 95% CI, 1.38–1.90; P < 0.00001), flour/grain (OR, 1.48; 95% CI, 1.11–1.97; P = 0.008), and textile dust (OR, 1.50; 95% CI, 1.08–2.09; P = 0.02) exposure were significantly associated with asthma.

Conclusions

Based on the studies evaluated, our meta-analysis results prompt that organic dust exposure is a risk factor inducing asthma, although precise analysis focus on specific organic dust materials is still warranted.

HLA and asthma phenotypes/endotypes: a review

Asthma is a complex chronic inflammatory disease of the airways caused by the interaction of genetic susceptibility with environmental influences. Genome-wide association studies (GWAS) represent the most powerful approach for asthma, that have identified several genes (e.g., IL18R1, IL33, SMAD3, ORMDL3, HLA-DQ and IL2RB loci). HLA super-locus is a genomic region in the chromosomal position 6p21. Since no gene can be considered as an asthma gene, able to reflect the complex etiology and the heterogeneity of the disease the terms 'phenotype' and more recently 'endotype' have been used. This review, according to literature availability, focuses on the relationship between human leukocyte antigens (HLA) region specifically the HLA class II genes and different asthma phenotypes/endotypes, such as allergic asthma/Th2 associated, occupational and aspirin-sensitive asthma. The most common HLA haplotypes in the different asthma phenotypes are HLA-DRB1in allergic asthma, HLA-DQB1in occupational asthma and HLA-DPB1 in aspirin-sensitive asthma. However, it is difficult to study the role of class II genes in vivo because of the heterogeneity of human population, the complexity of MHC, and the strong linkage disequilibrium among different class II genes. Despite the variation and the inconsistency of the HLA haplotypes and alleles in different types of asthma, the association between HLA class II genes and asthma has been demonstrated in the majority of studies.

An official American Thoracic Society proceedings: work-related asthma and airway diseases. Presentations and discussion from the Fourth Jack Pepys Workshop on Asthma in the Workplace

Work-related asthma is a common occupational lung disease. The scope of the Fourth Jack Pepys Workshop that was held in May 2010 went beyond asthma to include discussion of other occupational airway diseases, in particular occupationally related chronic obstructive pulmonary disease (COPD) and bronchiolitis. Aspects explored included public health considerations, environmental aspects, outcome after diagnosis, prevention and surveillance, and other work-related obstructive airway diseases. Consistent methods are needed to accurately estimate the comparative burden of occupation-related airway diseases among different countries. Challenges to accomplishing this include variability in health care delivery, compensation systems, cultural contexts, and social structures. These factors can affect disease estimates, while heterogeneity in occupations and workplace exposures can affect the underlying true prevalence of morbidity. Consideration of the working environment included discussion of practical methods of limiting exposure to respiratory sensitizers, methods to predict new sensitizers before introduction into workplaces, the role of legislated exposure limits, and models to estimate relative validity of various ameliorative measures when complete avoidance of the sensitizer is not feasible. Other strategies discussed included medical surveillance measures and education, especially for young individuals with asthma and new workers about to enter the workforce. Medical outcomes after development of sensitizer-induced occupational asthma are best following earlier diagnosis and removal from further exposure, but a subset may be able to continue working safely provided that exposure is reduced under close follow-up monitoring. It was recognized that occupationally related COPD is common but underappreciated, deserving further study and prevention efforts.

What do we know about asthma triggers? a review of the literature

OBJECTIVE

For patients with asthma, exacerbations and poor control can result from exposure to environmental triggers, such as allergens and air particulates. This study reviewed the international literature to determine whether a global checklist of common asthma triggers might be feasible for use as a research or management tool in clinical practice.

METHODS

Literature published from 2002 to 2012 was identified through PubMed and EMBASE using the following search terms: asthma, asthma triggers, prevalence, among others. A total of 1046 abstracts were found; 85 articles were reviewed covering six continents (number of articles): Africa (1), Asia (22), Australia (1), Europe (27), North America (22), and South America (4).

RESULTS

The literature consistently pointed to asthma triggers as one contributor to poor asthma control. Frequently cited triggers were similar across countries/regions and included allergens (particularly pollens, molds, dust, and pet dander), tobacco smoke, exercise, air pollutants/particulates, weather patterns/changes, and respiratory infections. Definitions of asthma triggers, how triggers are taken into account in definitions of asthma control, and scientific inquiry into optimal management techniques for triggers were inconsistent and sparse.

CONCLUSIONS

Given the apparent importance of triggers in attaining and maintaining asthma control, empirical research concerning optimal trigger management is needed. Results demonstrate that asthma triggers are similar across continents, suggesting a global checklist of triggers for use in research and clinical practice would be feasible.

Health disparities among occupations in Taiwan: a population study

OBJECTIVES

The first large-scale population survey was conducted in Taiwan to examine if and to what extent health disparities of four major chronic physical conditions exist among occupations.

METHODS

Face-to-face interviews about two risk behaviors (i.e., cigarette and alcohol use) and four major chronic physical conditions (i.e., cardiovascular disease, diabetes, liver disease and asthma) were conducted with 13,741 workers from nine major categories of occupations.

RESULTS

Health disparities among occupations were found based on a series of hierarchical logistic regression analyses after controlling for age, sex and two risk behaviors. In general, prevalence rates of cardiovascular disease among elementary occupations and skilled agricultural and fishery workers were approximately two to four times higher than those among other occupations. The above two occupations and plant and machine operators also had higher prevalence rates in diabetes and liver disease.

CONCLUSIONS

The results concerning health disparities among occupations provide policymakers and researchers with invaluable benchmarks of chronic physical conditions among occupations. The findings also suggest the importance of investigating causal relationship between these diseases and exposures at work, identifying and reducing unique risk factors and hazard exposures experienced by workers and conducting targeted surveillance and health promotion programs for at-risk occupations.

A meta-analysis on wood dust exposure and risk of asthma

Work-related asthma is the most common occupational respiratory disorder in the industrialized countries. It has been postulated that wood dust exposure may increase the risk of work-related asthma. The objective of this study was to assess, through a meta-analysis, the risk of developing work-related asthma associated with wood dust exposure. A systematic search of the literature was performed. Inclusion and exclusion criteria were applied and a quality scale used to measure the quality of the included studies was developed. Using standard meta-analysis techniques, studies were pooled using both random and fixed effects models. Nineteen studies were included which consisted of three cohort studies, twelve case-control studies and four mortality studies. The pooled relative risk (RR) of asthma among workers exposed to wood dust was 1.53 (95% CI 1.25-1.87). When the analysis was restricted to studies carried out on Caucasian populations, the pooled RR was 1.59 (95% CI 1.26-2.00) while the pooled RR of studies on Asian populations was 1.15 (95% CI 0.92-1.44). Wood workers present a higher risk of asthma. Future research should include careful evaluation of ethnicity and nativity as risk modifiers.