Abstract Rationale While indoor air pollution is a recognized contributor to adverse respiratory outcomes, the specific impact of chemical components within particulate matter ≤2.5 µm in diameter (PM2.5), particularly trace elements, on lung function remains poorly understood. Our aim was to assess the contribution of elemental constituents of PM2.5 on lung function in people with chronic obstructive pulmonary disease (COPD). Methods We analyzed data from two Massachusetts-based cohorts of people with COPD, comprising 777 observations from 291 participants: the Air Purification for Eosinophilic COPD Study (APECS) and the VA Boston Healthcare System COPD Study (VA COPD). Participants completed up to two pre-randomization visits over 3 months in APECS between 2021-2024, or up to four in-home assessments over 12 months in VA COPD between 2012-2017. Indoor PM2.5 samples were collected over approximately one week in each participant’s home, and concentrations of 17 trace elements, including aluminum (Al), bromine (Br), calcium (Ca), chlorine (Cl), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), lead (Pb), sulfur (S), silicon (Si), strontium (Sr), titanium (Ti), and zinc (Zn), were quantified via X-ray fluorescence (XRF). Quantile g-computation was used to estimate the joint association of the elemental mixture with pre-bronchodilator FEV1, FVC, and FEV1/FVC ratio. Cohort-specific associations were estimated first and subsequently pooled using random-effects meta-analysis. All models were adjusted for age, body mass index, height, and season; the APECS model was additionally adjusted for sex, which was not included in the predominantly male VA COPD cohort. Results The mean (SD) age of participants was 70.9 (8.5) years in APECS and 72.9 (8.4) years in VA COPD. We found that a simultaneous one-tertile increase across the 17-element mixture was associated with a significant reduction of -138 mL in FEV1 (95% CI: -275, -1) and a -3.9% lower FEV1/FVC ratio (95% CI: -6.9, -0.9) (Figure 1). The association with FVC was negative but not statistically significant (pooled estimate: -22 mL; 95% CI: -211, 167). The components analysis indicated that chlorine contributed most to the observed negative associations between indoor element mixtures and lung function. Conclusion Joint exposure to indoor trace element mixtures of PM2.5 was associated with lower FEV1 and FEV1/FVC ratio among people with COPD in two Massachusetts-based cohorts. These findings highlight the need to consider cumulative indoor pollutant mixtures in policies and interventions aimed at protecting respiratory health. This abstract is funded by: This work was supported by the National Institute of Environmental Health Sciences NIH Grants R01ES031252, R01 ES019853, R21 ES029637, and P30 ES000002, and by resources and the use of facilities at the VA Boston Healthcare System. The contents do not represent the views of the U.S. Department of Veterans Affairs or the United States Government. This publication was also made possible by USEPA grant RD-83479801 and RD-83587201. Its contents are solely the responsibility of the grantee and do not necessarily represent the official views of the USEPA. Further, USEPA does not endorse the purchase of any commercial products or services mentioned in the publication.
Ni et al. (Fri,) studied this question.