Spatiotemporal Variations in Ambient Ultrafine Particles and the Incidence of Childhood Asthma

Abstract

Word count: 3490At a Glance Commentary: Scientific Knowledge on the Subject: Ambient fine particulate matter (PM2.5) exposure in utero has been associated with the development of childhood asthma. However, little is known regarding the impact of ambient ultrafine particles (<0.1 μm) (UFPs) on childhood asthma development What this Study Adds to the Field: Our findings suggest that UFPs exposure during the second trimester of pregnancy was associated with an increased risk of developing asthma in children before age 6 independent of other air pollutants including NO2 and PM2.5. These findings highlight the need for further research on the effects of UFPs during the perinatal period on respiratory health in children. Online Data Supplement: This article has an online data supplement, which is accessible from this issue's table of content online at www.atsjournls.org 1 ABSTRACT Rationale: Little is known regarding the impact of ambient ultrafine particles (<0.1 μm) (UFPs) on childhood asthma development. Objective: To examine the association between prenatal and early postnatal life exposure to UFPs and development of childhood asthma. Methods: A total of 160,641 singleton live births occurring in the City of Toronto, Canada between April 1 st 2006and March 31 st 2012 were identified from a birth registry. Associations between exposure to ambient air pollutants and childhood asthma incidence (up to age 6) were estimated using random-effects Cox proportional hazards models, adjusting for personal-and neighborhood-level covariates. We investigated both single-and multi-pollutant models accounting for co-exposures to PM2.5 and NO2. Measurements and Main Results: We identified 27,062 children with incident asthma diagnosis during the follow-up. In adjusted models, second trimester exposure to UFPs (Hazard Ratio (HR) per interquartile (IQR) increase = 1.09, 95% CI: 1.06 -1.12) was associated with asthma incidence. In models additionally adjusted for PM2.5 and NO2, UFPs exposure during the second trimester of pregnancy remained positively associated with childhood asthma incidence (HR per IQR increase = 1.05, 95% CI: 1.01 -1.09). Conclusion: This is the first study to evaluate the association between perinatal exposure to UFPs and the incidence of childhood asthma. Exposure to UFPs during a critical period of lung development was linked to the onset of asthma in children, independent of PM2.5 and NO2. Abstract word count: 229

Association of bacterial load in drinking water and allergic diseases in childhood

“…It is well established that air pollution contributes to worsening asthma control and increases the risk of asthma exacerbations. Furthermore, perinatal exposure to ambient ultrafine particles (<0.1 mm diameter) and maternal exposure to traffic‐related NO 2 during pregnancy have been linked to the onset of asthma in children 18,19 . It is of note that we observed differences in allergic diseases between rural children using wells or mains water supply, with a dose‐response relationship between bacterial content in drinking water and the risk of allergies.…”

Exposure to ultrafine particles in children until 18 years of age: A systematic review

“…Some epidemiological studies have found associations between ultrafine particle exposure and respiratory effects such as asthma, inflammation processes in children, changes in children's blood pressure, and even alterations in cognitive development . In the same way, higher doses of UFP, as a consequence of an elevated environmental UFP concentration, have been correlated to larger lifetime cancer risks.…”

“…Furthermore, the alveolar region shows the highest percentage of deposition of UFP from these devices, the majority of the particles deposited being smaller than 100 nm. 81 Some epidemiological studies have found associations between ultrafine particle exposure and respiratory effects such as asthma, 82 inflammation processes in children, 16 changes in children's blood pressure, 17 and even alterations in cognitive development. 18 In the studies reviewed here, mean UFP levels in children-specific microenvironments were variable and oscillated between 0.1·10 4 and 14.0·10 4 part/cm 3 .…”

The Role and Potential Pathogenic Mechanism of Particulate Matter in Childhood Asthma: A Review and Perspective

“…Another important risk in the incidence of pediatric asthma is the composition of PM. Authors have suggested that perinatal exposure to UFPs during a critical period of lung development was linked to the onset of asthma in children, independent of PM 2.5 and NO 2 [20]. However, an investigation from Taiwan determined that particulate matter ≤ 2:5 μm (PM 2.5 ), particulate matter ≤ 10 μm (PM 10 ), sulfur dioxide (SO 2 ), and nitrogen dioxide (NO 2 ) were positively associated with childhood asthma hospitalization rate, while ozone (O 3 ) was negatively associated with childhood asthma hospitalization rate.…”