Association between exposure to specific PM 2.5 constituents and environment, lifestyle, and clinical parameters in patients with COPD

Background: Particulate matter of less than 2.5 micrometers (PM2.5) is associated with various adverse health outcomes. Limited evidence exists however regarding the effects of the individual constituents of indoor PM2.5 and whether their concentrations are affected by the environment or lifestyle. We here investigated the associations between these individual constituents and respiratory outcomes, the living environment, and daily life behaviors in patients with chronic obstructive pulmonary disease (COPD). Methods: This was a prospective panel study involving COPD patients recruited from three hospitals in the Republic of Korea. Detailed questionnaires on living environments and lifestyle practices were completed by the participants. Associations between indoor PM2.5 constituents and respiratory outcomes, living environments, and daily life behaviors were then analyzed. Correlation analyses were conducted using a Spearman’s rank-order or Pearson’s correlation. Results: A total of 89 stable COPD cases were included. Their mean age was 68.1 years and 84 (94.4%) were men. The median indoor PM2.5 concentration was 11.3 μg/m3. Titanium was significantly associated with small airway resistance. Higher concentrations of aluminum, bromine, and silicone correlated with more frequent exacerbations. Regarding the living environment, the copper concentrations were negatively correlated with the distance from a road and with the floor level of residence. A higher manganese concentration was associated with greater traffic volume. An increased ventilation time was associated with lower concentrations of copper and silicone, whereas the air purifier operation time on a day with a heavy dust level was negatively correlated with barium and titanium concentrations. Iron and manganese were negatively correlated with a frequency of cleaning the kitchen ventilator. Conclusion: PM2.5 comprises various chemical constituents, each showing different relationships with clinical parameters in patients with COPD. Such constituents may be affected by environmental factors or lifestyles and should be considered as part of individualized intervention strategies through further studies.