Can a housing environmental index establish associations between indoor risk indicators and clinical tests in persons with asthma?

Indoor PM2.5, VOCs and asthma outcomes: A systematic review in adults and their home environments

INTRODUCTION

As the amount of time people spend indoors increases globally, exposure to indoor air pollutants has become an important public health concern. Asthma is a complex disease caused and/or exacerbated by increased exposure to diverse chemical, physical and biological exposures from multiple indoor and outdoor sources. This review aims to investigate the relationship between increased indoor PM and VOC concentrations (i.e. objectively measured) and the risk of adult asthma in higher-income countries.

METHODS

Eleven databases were systematically searched on the February 1, 2019 and again on the February 2, 2020. Articles were limited to those published since 1990. Reference lists were independently screened by three reviewers and authors were contacted to identify relevant articles. Backwards and forward citation chasing was used to identify further studies. Data were extracted from included studies meeting our eligibility criteria by three reviewers and assessed for quality using the Newcastle-Ottawa scale designed for case-control and cohort studies.

RESULTS

Twelve studies were included in a narrative synthesis. We found insufficient evidence to determine the effect of PM2.5 on asthma in the indoor home environment. However, there was strong evidence to suggest that VOCs, especially aromatic compounds, and aliphatic compounds, were associated with increased asthma symptoms.

DISCUSSION & CONCLUSION

Although no single exposure appears to be responsible for the development of asthma or its associated symptoms, the use of everyday products may be associated with increased asthma symptoms. To prevent poor health outcomes among the general population, health professionals and industry must make a concerted effort to better inform the general population of the importance of appropriate use of and storage of chemicals within the home as well as better health messaging on product labelling.

Home environment allergen exposure scale in older adult cohort with asthma

OBJECTIVES

Home environmental exposures are a primary source of asthma exacerbation. There is a gap in decision support models that efficiently aggregate the home exposure assessment scores for focused and tailored interventions. Three development methods of a home environment allergen exposure scale for persons with asthma (weighted by dimension reduction, unweighted, precision biomarker-based) were compared, and racial disparity tested.

METHODS

Baseline measures from a longitudinal cohort of 187 older adults with asthma were analyzed using humidity and particulate matter sensors, allergy testing, and a home environment checklist. Weights for the dimension reduction scale were obtained from factor analysis, applied for loadings > 0.35. Scales were tested in linear regression models with asthma control and asthma quality of life outcomes. Racial disparities were tested using t tests. Scale performance was tested using unadjusted regression analyses with asthma control and asthma quality of life outcomes, separately.

RESULTS

The 7-item empirically weighted scale demonstrated best performance with asthma control associations (F = 4.65, p = 0.03, R2 = .02) and quality of life (F = 6.45, p = 0.01, R2 = .03) as follows: evidence of roach/mice, dust, mold, tobacco smoke exposure, properly venting bathroom fan, self-report of roach/mice/rats, and access to a HEPA filter vacuum. Pets indoors loaded on a separate scale. Racial differences were observed (t = - 3.09, p = 0.004).

CONCLUSION

The Home Environment Allergen Exposure Scale scores were associated with racial disparities. Replicating these methods in populations residing in high-risk/low-income housing may generate a clinically meaningful, tailored assessment of asthma triggers. Further consideration for variables that address allergic reactivity and biomarker results is indicated to enhance the potential for a precision prevention score.