In a recent study published in Environmental Epidemiology, researchers evaluated the role of exposure to low levels of ambient ultrafine particles in the development of asthma in children.
According to the study’s lead author, Alan da Silveira Fleck, findings from the population-based Canadian cohort suggested that onset of childhood asthma was not associated with prenatal or childhood exposure to low concentrations of ultrafine particles.
The population-based birth cohort included 352,966 children born in Montreal, Canada, between 2000 and 2015. Of these, 30825 children developed asthma and were followed from birth until a maximum of 13 years of age. The researchers used a land use regression model to estimate annual mean concentrations of ambient ultrafine particles, and prenatal exposure was determined via residential postal code at birth.
Low-Levels of Ultrafine Particles Don’t Appear to Increase Asthma Risk
Ultrafine particle exposure in childhood was adjusted for time-varying residence location, and hazard ratios (HR) for asthma incidence were calculated with Cox proportional hazard models adjusted for age, sex, neighborhood material and social deprivation, calendar year, and concurrent exposure to ambient nitrogen dioxide and fine particles.
According to the authors, the mean prenatal and childhood exposure to ultrafine particles were 4706 particles/cm3 (interquartile range [IQR], 3785 particles/cm3) and 24525 particles/cm3 (IQR, 3427 particles/cm3), respectively.
Ultimately, the authors suggested that neither prenatal nor childhood exposure to ultrafine particles were associated with an increase in childhood asthma onset in single pollutant models (HR per IQR increase, 0.99; 95% CI, 0.98-1.00). Authors added that models adjusted for coexposure to other pollutants were similar.