2675

Background: Social environmental factors such as unfavorable neighborhood cohesion may contribute to poor sleep by, for example, activating stress pathways. Methods: Using pooled cross-sectional data from 144,776 participants of the 2013-2017 National Health Interview Survey (NHIS), we examined overall and race/ethnicity-specific associations between neighborhood social cohesion and sleep health among White, Black, Hispanic/Latino, and Asian adults. Neighborhood social cohesion score (NSC) was measured based on self-reported responses to four questions related to trust and support, which were categorized into low, medium, and high groups. Very short sleep duration was defined as <6 hours; short sleep <7 hours, recommended sleep 7-8 hours, and long sleep ≥9 hours. Sleep difficulties were assessed based on “trouble falling asleep 3+ days,” “trouble staying asleep 3+ days,” “waking up feeling rested 4+ days,” and “took sleep medication ≥1 times” all in the previous week. Adjusting for sociodemographics, health behaviors, and health indicators, Poisson regression with robust variance was used to estimate prevalence ratios (PRs) and 95% confidence intervals (CIs) for sleep duration and difficulty by low vs. high NSC and medium vs. high NSC. Results: Among 144,776 adults, mean age was 47±0.1 years, 48% were men, and 69% white. Overall, low vs. high NSC was associated with a higher prevalence of very short (PR=1.32; 95% CI: 1.25-1.40) and short (PR=1.19; 95% CI: 1.16-1.22) sleep duration. Low vs. high NSC was positively associated with very short sleep duration among Whites (PR=1.37; 95% CI: 1.28-1.47), Blacks (PR=1.13; 95% CI: 1.01-1.28), and Hispanics/Latinos (PR=1.30; 95% CI: 1.11-1.53). Among Asians, low NSC was associated with short sleep duration (PR=1.19; 95% CI: 1.06-1.32). Conclusions: Sleep difficulties were more prevalent among all racial/ethnic groups with less than high NSC. Low neighborhood social cohesion was associated with shorter sleep duration and sleep difficulty across racial/ethnic groups, and more research is warranted.

2565

Background. Vegetated landscapes (i.e., greenspace) may increase or decrease risk of asthma exacerbation through effects on pollen levels, localized climates (e.g., heat islands), air pollution, or child’s behaviors.
Methods. We investigated the association between neighborhood greenspace and pediatric asthma exacerbation (age <18 years) in the City of Philadelphia, by conducting a case-control study based on electronic health records (EHR) from the Children’s Hospital of Philadelphia (CHOP) Care Network. Our study included cases from 8017 outpatient clinic visits, 5953 emergency department (ED) visits, and 4401 inpatient encounters, with controls selected from non-exacerbation clinical encounters for asthma. We studied various greenspace measures, including overall greenness (i.e., vegetation density), tree canopy, grass/shrub coverage, and impervious landcover, within various buffer sizes surrounding the child’s residence. We used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI), adjusting for child- and neighborhood level sociodemographic factors.
Results. Lower odds of asthma exacerbation were observed in association with high levels of greenspace near the home (>75^th percentile vs. ≤25^th percentile) for ED cases, such as reduced odds of ED visits by 29% with high tree canopy coverage (OR=0.71, 95% CI= 0.61, 0.83), and 16% with high grass/shrub coverage (OR=0.84, 95% CI: 0.74, 0.97). Impervious surface landcover near the home was associated with greater odds of asthma exacerbation for ED (high vs. low: OR=1.50, 95% CI: 1.28, 1.75) and inpatient cases (OR=1.20, 95% CI: 1.02, 1.42). Small reductions in risk of outpatient clinic cases or inpatient cases in association with greater amounts of vegetation near the home were not statistically significant in the best-fitting models.
Conclusions. Our findings suggest a protective effect of residential neighborhood greenspace against asthma exacerbation; however, differing results among treatment settings requires further assessment of confounding by indication and effect modification.

2437

Although the goals of most air-quality policies is to reduce direct emissions from the source points, it also aims to reduce health burden due to exacerbated environmental pollution. Therefore, assessing the impact of environmental policies on related health outcomes is important. In Korea, especially in Seoul and Incheon, interventions for reducing traffic-related air pollutants (TRAP) were aggressively implemented since 2007. TRAP is a known risk factor for asthma. In this study, we aimed to investigate whether the interventions had a beneficial impact on hospitalization by asthma.Hospital records for hospitalization by asthma in the study (Seoul and Incheon) and the reference population (Daejeon, Daegu, Busan, and Ulsan) were abstracted from the database in National Health Insurance Service during 2003 to 2011. A controlled interrupted time series design (C-ITS) was adopted to assess the impact of air pollutants emission reduction policies on hospitalization by asthma. Long-term background trends were adjusted using the trends of reference cities. Various sensitivity analyses, including simple-ITS, and C-ITS with false-intervention and with simulated PM10 concentration when there was no intervention, were conducted to give a robustness of our study result.Emissions from traffic-related air pollutants were significantly reduced after 2007. Estimated numbers of prevented hospitalization for asthma in Seoul were 10,377 (14.1%) and 6,011 (8.7%) depending on the reference population (Daejeon and Daegu). For Incheon, estimated numbers of prevented hospitalization for asthma were 3,207 (11.7%) and 2,470 (9.2%) depending on the reference population (Busan and Ulsan). Potential beneficial effects of the interventions on asthma were also found in the sensitivity analysis. Our study provides supportive evidence for potential beneficial effects of interventions for reducing TRAP on hospitalization for asthma in Seoul and Incheon. More studies are needed to determine the impact of such environmental policy implementation on other diseases associated with air pollutants in Korea.

2333

The extensive distribution of per- and polyfluoroalkyl substances (PFAS) has led to concerns about environmental and human health impacts. Risk assessments of contaminated areas in Australia have evaluated PFAS exposure pathways but have not quantified PFAS exposure levels in affected communities or the associated health risks. The PFAS Health Study aims to investigate multiple aspects of the PFAS exposure pathway, including the environmental and behavioural factors that influence PFAS body burdens, as well as health outcomes and concerns associated with PFAS exposure. We conducted a cross-sectional study of current and former residents and workers of three Australian communities affected by environmental PFAS contamination−Williamtown in New South Wales, Oakey in Queensland and Katherine in the Northern Territory−and three comparison communities. This Study included biomonitoring and a self-administered survey. The findings will guide our understanding of the determinants of PFAS exposure, associations with self-reported psychosocial or physical health outcomes and concerns, and actions that residents have taken in PFAS affected communities to reduce their exposure. The study design was informed by a systematic review of the health effects of PFAS exposure and a qualitative study of the health and social concerns of people living in Australian communities affected by environmental PFAS contamination. This study will produce knowledge to assist affected communities in understating the impact, if any, of PFAS exposure on their health and to aid policy makers in responding to PFAS contamination issues. The PFAS Health Study is the first of its kind in Australia and will add to the body of international literature around the effects of environmental PFAS exposure on human health.

1248

Background: There is biologic rationale for associations between ambient PM_2.5 exposure and type 2 diabetes. However, studies of these associations demonstrate mixed results, potentially due to differences in: PM_2.5 estimation by community types and regions; PM_2.5 estimation methods that optimize temporal vs. spatial variability; and exposure lags and durations assigned to individuals for evaluation with diabetes outcomes. Methods: We evaluated several PM_2.5 data sources and exposure assignment choices for 10,332 participants free of diabetes at baseline (2003-2007) and with follow-up data on diabetes in the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. We calculated exposure durations of 2-weeks, 30-days, and 1-year; lagged 1-day, 6-months, and 1-year prior to baseline, and evaluated these by: US region (Northeast, South, Midwest, and West); community type (high density urban, low density urban, suburban and small town, and rural); and year for two sources of PM_2.5: CDC EPA Downscaler model and CDC Wonder data modeled from NASA satellite observations and EPA monitor data. Results: Participants in the analysis had a mean (SD) age of 63.0 (8.5) years, were 55.8% female; 32.4% black. The mean (SD) PM_2.5 estimates from CDC Wonder were 13.5 (4.2) µg/m³, 13.5 (3.6) µg/m³, and 13.3 (2.0) µg/m³, for 2-week, 30-day, and 1-year exposure periods, respectively. One-way analysis of variance (ANOVA) of PM_2.5 exposure estimates of all durations showed significant differences (p ≤ 0.01) by community type, region, and year. Differences by region and community type became more pronounced with longer exposure durations. Analysis of additional exposure lags and durations is in progress. Conclusions: These results suggest that exposure assignment choices can either exacerbate or mitigate underlying spatial differences in this cohort, which can lead to differential associations between PM_2.5 and diabetes. Future work should focus on better exposure classification in order to more clearly estimate this association.

3261

PM_2.5 is an air pollutant that can cause various adverse health effects. Although the fixed ambient air monitoring stations provides ambient PM_2.5 concentration within a community, it is still weak to assess actual exposure of population account for time-activity patterns. However, the exposure of the entire population in a region of interest may be estimated by classifying the population according to time-activity pattern and modeling their exposure. In this study, we tried to suggest the methodology to assess exposure to PM_2.5 of entire population in a region of interest. The five field technicians representing similar time-activity groups (STG) of preschool children, students, housewives, office workers, and the elderly conducted exposure simulation with PM_2.5 personal exposure monitor in Guro-gu, Seoul, Korea. The PM_2.5 exposure concentrations (c_s) were modeled by interpolation (point in polygon, inverse distance weighted and ordinary kriging) and regression model using GPS data and sensor-based air monitoring instruments network and compared with MicroPEM data (c_m). The exposure of the entire population to PM_2.5 was estimated by population-weighted average through Monte-Carlo simulation. The elderly had the highest average c_m follows by office workers, housewives, preschool children, and students. The correlation between c¬m and c_s was good in order of ordinary kriging (R²=0.822), inverse distance weighted (R²=0.747), and point in polygon method (R²=0.721). The 33.8% of the entire population exposed to PM_2.5 higher than Atmospheric Environmental Standard of PM_2.5 for 24-hour average. In this study, the possibility of assessing the exposure of the entire population for real-time and long-term cumulative exposure was suggested by applying this methodology, and it is expected that the exposure surveillance system can be developed based on these results.

2906

Background: Aggregate and limestone mining in counties - especially Bexar and Comal, north of the city of San Antonio have been a cause of health concern recently. Aggregate mining particularly in residential areas can be problematic due to heavy truck traffic transporting the material resulting in vehicular air pollution as well.
Methods: PM species were sampled at four locations north of San Antonio. The data was collected using a TSI Air Quality Sampler that sampled PM1, PM2.5, PM10, wind speed, wind direction, temperature, and relative humidity. Continuous data (1 minute averages) was recorded for the entire study period. The instrument was stationed at every location for a period of 7 days. The four locations were a ranch, open field, residential compound, and an elementary school. The sampling was conducted in August and September 2019.
Results: The PM1 and PM2.5 levels were low at all the four sites in contrast to the PM10 levels. This suggests that the PM in Bexar and Comal Counties are impacted by mining activities primarily. For example, the seven day average for PM2.5 was about 8.6 ug/m3 at the ranch and PM10 values were around 15.8 ug/m3. PM species were highest at the residential compound due to the close proximity to an active mining area.
Conclusions: Mining activities for limestone and aggregates should be limited in areas that are away from residential locations to minimize the respiratory exposure burden of the local population. More sampling needs to be done in other seasons as well.

2790

Background - The essential trace element iodine is needed for an optimal (neuro)-development of the fetus via the production of thyroid hormones. Recent findings indicate that exposure to ambient air pollution was linked with mild thyroid dysfunction during pregnancy. We hypothesize that air pollution might alter the placental iodine concentrations during gestation. Methods -We determined the placental iodine concentrations in 470 mother newborn pairs included in the ENVIRONAGE birth cohort. Maternal residential PM_2.5 (particulate matter with a diameter &lt; 2.5 µm), NO₂, and black carbon concentrations were determined during the pregnancy using a high-resolution air pollution model. Using distributed lag nonlinear models (DLNM), we modeled the gestational week-specific association between placental iodine concentrations and air pollutants. Results - Significant inverse associations were observed between gestational exposure to PM_2.5 at weeks 28 to 35 and placental iodine concentrations. Cumulative estimates over the trimesters of pregnancy showed that in the third trimester of pregnancy (week 27 until delivery) an increase of 5 µg/m³ in PM_2.5 exposure was associated with a decrease of 0.85 µg/kg in placental iodine concentration (95%CI: -1.56 to -0.14). These associations were adjusted for maternal pre-pregnancy BMI, gestational weight gain, household smoking behavior, maternal alcohol consumption, maternal education, maternal age, vitamin use, gestational age, date and season at delivery, and newborns’ sex. No significance was found between placental iodine load and the ambient NO₂ or black carbon exposure.Conclusions- Gestational exposure to PM_2.5 is linked with a lower placental iodine concentration. This decrease indicates that ambient air pollution might interfere with the normal uptake mechanisms of iodine, which could results in worse neurocognitive health outcomes later in life.

2237

Background. Wildland firefighters (WFFs) work under intense and demanding conditions in the protection of human health, life, and property. Air pollutant exposures, heat, noise, disrupted sleep, emotional and psychological stress, and extreme physical exertion each may have short-term consequences for WFFs. Although countless population-based studies have established the long-term consequences of these exposures individually, to date little research has been devoted to their chronic effects in WFFs. The health and fitness of WFFs and the duration and intensity of their varied exposures combined with their limited use of personal protective equipment make WFFs a unique population in need of study. Methods. Occupational history as a WFF was assessed using Incident Qualification and Certification System (IQCS) responder records. These records contain information on specific fires to which a WFF was assigned, the duration of the assignment, and jobs for which a WFF is qualified and the number of times those jobs were performed. IQCS records were linked to Department of the Interior Wildland Fire Medical Standards Program medical screening examinations performed between 2014 and 2017. Results. Between 2014 and 2017, over 10,000 prospective and current WFFs completed comprehensive medical screening examinations to determine fitness for arduous duty firefighting. The median age was 33 years, and 85% of participants were male. Measured median systolic and diastolic blood pressures were 122 and 78 mm Hg, respectively, and 13% had an abnormal resting electrocardiogram. Forty-one percent of participants had available IQCS occupational history records.Conclusions. Preliminary analyses emphasized cardiovascular health among WFFs, and future work will investigate other health measures and their association with occupational history. The project establishes a framework for expanded studies of the occupational health risks linked to wildland firefighting, and findings have the potential to guide future screening and surveillance programs.

2108

Background The Forkhead box O (FOXO) gene is a candidate longevity gene. Residential greenness is an important built environment factor strongly associated with mortality. There was no previous study on the interaction between FOXO and residential greenness based on our knowledge. Methods We studied 3,179 participants aged 65 and older from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We measured residential greenness by satellite derived Normalized Difference Vegetation Index (NDVI) using a 500-m radius around each residential address. We calculated contemporaneous NDVI, cumulative NDVI and changes in NDVI over time. We used adjusted Cox-proportional hazard regression models to assess main effects and interaction of FOXO SNPs and residential greenness on mortality risk. Results We found participants with two minor allele copies of FOXO3A SNPs had lower mortality risk than those with zero copy (HR: 0.803 95% CI: 0.654, 0.987 for rs4946936, HR: 0.807 95% CI: 0.669, 0.974 for rs2802292, HR: 0.803 95%CI: 0.666, 0.968 for rs2253310). We found no mortality difference among different genotypes for FOXO1A SNPs rs17630266, rs2755209 and rs2755213. Higher contemporaneous NDVI was associated with lower mortality risk (HR: 0.887 95% CI: 0.863, 0.911 for 0.1 unit of NDVI). The protective effect of NDVI was stronger among participants with two minor allele copies of rs2802292 SNP compared with the ones with zero copy (Interaction term P<0.05), while not different between participants with one copy and zero copy.Conclusions We found gene-environment interaction between FOXO and residential greenness on mortality in this population study. A higher level of greenness may interact with FOXO pathways.

1997

Background Myocardial infarction (MI) and ambient fine particulate matter (PM_2.5) pollution are two global public health concerns. Evidence investigating the association between PM_2.5 and acute incidence of MI in developing countries is limited. Methods A multicenter study based on a time-stratified case-crossover design including 36,679 cases from MI incidence registry data and PM_2.5 site monitoring data was conducted. Results With a 10 μg/m³ increase in PM_2.5 concentration, there was an increase of 0.98% (0.40%, 1.57%) in acute incidence risk of MI on day lag02. The corresponding values for males and individuals aged over 74 years were 1.58% (95% CI: 0.82%, 2.35%) and 1.19% (95% CI: 0.35%, 2.05%) respectively, indicating higher risks than other groups. The non-linear concentration-response curve indicated a steeper slope under daily PM_2.5 below 50μg/m³ and the marginal avoided premature morbidity attributed to per 10μg/m³ reduction became larger under the current air quality standard.Conclusion This study is the first multicenter study to examine the association between the acute incidence of MI and short-term exposure to PM_2.5 in China. We provide solid evidence that PM_2.5 is a risk factor for accelerating MI incidence. A susceptible population was identified. The robust findings from this study may suggest the necessity for a continuous reduction of PM_2.5 concentration from the perspectives of public health.

1878

Background: Although associations between particulate matter <2.5 microns (PM_2.5) and cardiovascular disease (CVD) and mortality are well-established, less is known regarding the joint impact of PM_2.5 and neighborhood socioeconomic status (nSES). Our objective was to investigate this interaction in a nationwide cohort of U.S. women. Methods: We used time-varying Cox proportional hazards models, conditioned on age and calendar time, to assess main and interaction effects of PM_2.5 and nSES on risk of CVD (stroke, myocardial infarction) and mortality among 100,257 women in the Nurses’ Health Study between 1986 and 2008. Incident CVD (n=6,445) and mortality (n=10,186) cases were ascertained from medical or death record reviews. We created Census tract-level nSES scores by summing z-scores (where increasing scores were associated with affluence) of selected nSES metrics (e.g., race, education, income, home value, nativity, unemployment), and calculated time-varying 24-month average PM_2.5 exposure using residential address history. Models were adjusted for time-varying demographic, lifestyle (e.g., diet, physical activity, smoking), and individual-level SES factors. Results: In multivariable adjusted models, increases in nSES (Hazard Ratio [HR]_CVD: 0.98, 95% Confidence Interval [CI]: 0.97, 0.99; HR_mortality: 0.99, 95% CI: 0.99, 1.00, per 1 unit increase) and PM_2.5 (HR_CVD: 1.03, 95% CI: 0.95, 1.12; HR_mortality: 1.04, 95% CI: 0.97, 1.11, per 10 µg/m³ increase) were associated with incident CVD and mortality rates, although the associations with PM_2.5 did not reach statistical significance. The interaction between PM_2.5 and nSES was statistically significant for CVD risk (p<0.001) and mortality (p<0.013); associations with mortality were strongest among the least affluent neighborhoods, while associations with CVD were weakest in areas of least and greatest affluence. Conclusions: Our results suggest that PM_2.5 and nSES exposures are associated with small changes in rates of mortality and CVD incidence. These exposures interact in a complex fashion, even within a relatively demographically homogeneous cohort of women.