This project is an NIH-funded five-year study (2022-2027). Drs Iona Cheng at UCSF, Anna Wu at USC, and Jun Wu at UCI are multi-PIs in this study. The study will investigate the impacts of extreme heat and wildfire smoke on adult life expectancy, leveraging the unique epidemiological resources of the Multiethnic Cohort Study, a large longitudinal study that includes 112,000 adult men and women from California, who were ages 45-75 at enrollment in 1993-1996 with strong representation of diverse racial/ethnic and socioeconomic groups. Findings will expand our understanding of the contribution of long-term extreme heat and wildfire smoke on life expectancy.
As the frequency of major wildfires increases across the western United States due to warming temperature trends and other factors, a growing public health threat is exposure to harmful wildfire smoke. In this project, we are using the recently developed low-cost air pollution sensor network known as PurpleAir to identify the impact of the California wildfires to air pollution in surrounding communities. Additionally, we are investigating the relationship between such impacts and various socioeconomic factors at the Census tract level to identify populations that are being disproportionately impacted. The goal of this research is to advance our understanding of "who" is being impacted by wildfire smoke so as to better inform the deployment of local, state, and federal resources in a way that equally and equitably protects public health in the face of an growing crisis.
Anqi Jiao will be working on a UCI Solutions that Scale Fellow project entitled "Impact of Heat Exposure on Pregnancy Outcomes: Climate Adaptation by Modifiable Built Environment Factors". In this project, she will 1) examine the association of heat exposures with preterm birth and severe maternal morbidity and the impact of climate adaptation factors (AC usage, more green space, etc.) using a comprehensive, high quality and large clinical dataset; 2) estimate reduced number of preterm birth and severe maternal morbidity incidences given changes in climate adaptation factors and identify subpopulations that may benefit the most from adaptation interventions; and 3) conduct city focus groups to identify how adaptation measures that can be "scaled up" in adaptation initiatives and plans.
Background. Exposure to high air temperature in late pregnancy is increasingly recognized as a risk factor for preterm birth (PTB). However, the combined effects of heatwaves with air pollution and green space are still unexplored. In the context of climate change, investigating the interaction between environmental factors and identifying communities at higher risk is important to better understand the etiological mechanisms and design targeted interventions towards certain women during pregnancy.
Objectives. To examine the combined effects of heatwaves, air pollution and green space exposure on the risk of PTB.
Methods. California birth certificate records for singleton births (2005-2013) were obtained. Residential zip code-specific daily temperature during the last week of gestation was used to create 12 definitions of heatwave with varying temperature thresholds and durations. We fit multi-level Cox proportional hazard models with time to PTB as the outcome and gestational week as the temporal unit. Relative risk due to interaction (RERI) was applied to estimate the additive interactive effect of air pollution and green space on the effect of heatwaves on PTB.
Results. In total, 1,967,300 births were included in this study. For PM2.5, PM10 and O3, we found positive additive interactions (RERIs > 0) between heatwaves and higher air pollution levels. Combined effects of heatwaves and green space indicated negative interactions (RERIs < 0 ) for less intense heatwaves (i.e. shorter duration or relatively low temperature), whereas there were potential positive interactions (RERIs > 0) for more intense heatwaves.
Conclusion. This study found synergistic harmful effects for heatwaves with air pollution, and potential positive interactions with lack of green space on PTB. Implementing interventions, such as heat warning systems and behavioral changes, targeted toward pregnant women at risk for high air pollution and low green space exposures may optimize the benefits of reducing acute exposure to extreme heat before delivery.
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