Associations between green space and preterm birth: Windows of susceptibility and interaction with air pollution

The association between tree planting and birth outcomes

Multiple studies have found that exposure to greenspace during pregnancy is associated with increased birthweight (Hu et al., 2021) and a reduced probability of a small-for-gestational-age birth. However, because exposure to greenspace is associated with demographic correlates of health, studies may suffer from residual confounding. In addition, results may be influenced by the self-selection of healthier women into greener neighborhoods. We address these limitations by using the number of trees planted around maternal address as a novel exposure metric. Compared to existing tree cover, new tree planting is less prone to residual confounding or self-selection bias. We found that each tree planted within 100 m of maternal address within the last 10 years was associated with a 2.3 g (95 % CI: 1.5-3.0) increase in birth weight. In addition, we found that 1-SD increase in tree planting was associated with a 4.3 % (95 % CI: 0.3 to 8.2 %) reduced risk of a small-for-gestational-age birth and a 4.9 % (95 % CI: 0.3 to 9.3 %) reduced risk of a preterm birth. All models controlled for mother's race/ethnicity, education, major road density, and existing tree canopy. Our finding that both newly-planted and established trees are associated with improved birth outcomes strengthens the evidence that trees may be an effective public-health intervention.

Adverse associations of pre-pregnancy exposure to PM2.5 and its components with fetal growth alleviated by residential greenness: a prospective cohort study

Maternal exposure to fine particulate matter (PM2.5) and residential greenness both influence fetal growth. No previous studies have examined their sex-specific and interaction effects. We aim to evaluate the sex-specific effects in these associations and exposure interactions. This study involved 1,275 mother-child pairs enrolled in the Ma'anshan birth cohort in China. Pre-pregnancy exposure to PM2.5 and its components was assessed using a spatiotemporal model based on maternal addresses, while residential greenness was estimated through the normalized difference vegetation index (NDVI) based on satellite data. Fetal parameters-including biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL), and estimated fetal weight (EFW)-were measured during pregnancy via ultrasound. To examine associations between these exposures and both continuous and categorical outcomes, generalized estimating equations (GEE) and generalized linear regression were applied. Subgroup analyses were conducted to evaluate sex-specific effects. Pre-pregnancy exposure to PM2.5, OM, BC, SO42-, NH4+, and NO3- was correlated with decreased Z-scores of fetal parameters (BPD, FL, EFW, AC) during the second trimester, particularly in male fetuses. In the third trimester, we found that the Z-scores of AC (0.081, 95% CI: 0.001, 0.160) and EFW (0.097, 95% CI: 0.008, 0.185) increased with each interquartile range (IQR) increase in residential greenness. We observed the effect modification of PM2.5 and its components on the relationship between residential greenness and fetal growth in utero. Residential greenness can mitigate the adverse effects of PM2.5 and its components prior to pregnancy on fetal growth. Our findings suggest that increased residential greenness during pregnancy preparation may help alleviate air pollution's detrimental effects on fetal growth.

Associations of prenatal exposure to residential greenspace and active living environments with cerebral palsy: A population-based cohort study in Ontario, Canada

Background

Prenatal exposure to environmental factors, such as greenspace and active living environments, has been associated with numerous health benefits, including improved neurodevelopmental outcomes. Although cerebral palsy (CP) is not typically linked to these exposures, emerging evidence suggests that exposure to environmental factors during pregnancy may influence brain development, making it important to explore their potential role in CP risk.

Methods

We conducted a retrospective cohort study using health administrative data from Ontario, Canada, between 1 April 2002 and 31 December 2020. We identified 1,436,411 mother-infant pairs, of which 2,883 were diagnosed with CP during the follow-up period. Exposures of interest included the Normalized Difference Vegetation Index (NDVI), Green View Index (GVI), and park proximity. The Canadian Active Living Environments index was also utilized. Cox proportional hazards models estimated hazard ratios (HRs) for CP risk associated with these environmental exposures, adjusting for potential confounders.

Results

Interquartile range (IQR) increases in NDVI (HR = 1.040; 95% confidence interval [CI]: 0.987, 1.096; per IQR = 0.1) and GVI (HR =0.989; 95% CI: 0.943, 1.038; per IQR = 10.05%) were not significantly associated with CP risk. Similar results were found for quartile increases of NDVI and GVI. Residential proximity to parks at birth was associated with a reduction in CP risk (HR = 0.946; 95% CI: 0.904, 0.990; per 0.06 increase in park proximity index), after adjusting for active living environment and air pollution.

Conclusions

Our study suggests that living closer to parks reduces the risk of CP. Further research should investigate these protective effects and consider other dimensions of greenspace quality and usability.

Associations between short-term exposure to fine particulate matter with ischemic stroke mortality and the role of green space: a time-series study in Zibo, China

Background

Previous studies on associations between short-term exposure to fine particulate matter (PM2.5) and ischemic stroke (IS) mortality reported inconclusive results. Additionally, whether and how PM2.5 and green space interact to precipitate IS deaths remains unclear. We aimed to examine the impacts of short-term exposure to PM2.5 on IS mortality and the role of green space in the association.

Methods

We collected data on daily IS deaths, daily PM2.5 concentrations, and monthly normalized difference vegetation index (NDVI) in Zibo City from 2015 to 2019. Generalised additive models were adopted to investigate the short-term impacts of PM2.5 on IS mortality, and subgroup analyses were used to examine effect modification by population characteristics. Stratified analyses by green space levels and joint effect model were conducted to test the interactions of PM2.5 and green space on IS mortality.

Results

A total of 10 799 IS deaths were included in our study. Exposure to PM2.5 was associated with an increased risk of IS mortality, with odds ratios (ORs) of 1.0263 (95% confidence interval (CI) = 1.0017, 1.0516) for each interquartile range (IQR) increase in PM2.5 on lag0 and 1.0317 (95% CI = 1.0016, 1.0627) on lag01. The links between PM2.5 and IS mortality were not significantly different across genders, ages, or PM2.5 zones. Furthermore, our results showed that the effects of PM2.5 on IS mortality were higher in low levels of green space. Specifically, for each IQR increase in PM2.5, the ORs (95% CIs) of IS death in the low level and the high level of NDVI were 1.0287 (95% CI = 1.0019, 1.0563) and 0.9934 (95% CI = 0.9296, 1.0615), respectively. In addition, PM2.5 and NDVI exhibited significant interactive effects on IS mortality, with relative excess odds due to interaction (REOI) of greater than 0.

Conclusions

Our findings showed that PM2.5 was significantly associated with increasing odds of IS mortality. Furthermore, there were synergetic impacts between PM2.5 and lack of greenness on IS mortality. Our results suggest that expanding green spaces, such as increasing park coverage and street greening, along with regulating industrial emissions to reduce PM2.5 levels, can help prevent premature deaths from IS.

Does inhabitant's fertility intention respond to housing status in the urban built environment: evidence from China

Background

The total fertility rate in China has been dropping in recent years, and this continuing trend has led to a series of problems. China has experienced periods of urbanization and housing reforms, leading to a significant boom in the real estate market. Housing status appears to be an essential factor influencing the fertility-related decisions of residents in China.

Methods

We use cross-sectional data from a nationally representative large-scale tracking survey targeting the labor force in China. The research sample for this study comprised data from Chinese adults between the ages of 20 and 45. We highlight the importance of housing mortgages on fertility intention based on the Poisson regression model.

Results

Data was collected from a total of 7,512 inhabitants. The results show the following: 1) Housing status is closely related to fertility intention, while housing mortgage and water contamination are negatively affected. 2) The urban built environment, social environment, and individual characteristics affecting fertility intention mainly occur in urbanization rate, green coverage rate in urban built-up areas (GCR), life satisfaction, mental health, age, gender, marital status, political status, and education status. Urbanization rate, GCR, life satisfaction, and mental health positively influence resident's fertility intention, whereas women and single show lower fertility intention. 3) In particular, there are significant regional differences in the mechanism of fertility intention. Such intention in the eastern and central regions is primarily related to housing mortgages, urban built environment, the degree of contamination in the habitat, and socioeconomic factors, while the intention in the northeastern region is related to soil contamination. Fertility intention in the western and northeastern region are strongly related to mental health.

Estimating avoidable burden of stillbirth attributable to greenness improvement in Iran

INTRODUCTION

Expanding evidence suggests beneficial impacts of greenspace on human health, yet the relationships between greenness and stillbirth remain unknown. This study aimed to quantify the risk and burden of stillbirth associated with maternal greenness exposure during pregnancy.

METHODS

A total of 3,982,304 eligible birth records across 31 provinces in Iran from 2013 to 2018 were included in this study. Greenness exposure during pregnancy was assessed using the satellite-based normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) with multiple buffers. Stillbirth was defined as the birth of babies with no signs of life at ≥22 weeks of gestation. Multivariable-adjusted logistic regression models were employed to investigate greenness-stillbirth associations. To estimate the exposure-response functions, greenness exposures were fitted as smooth terms using restricted cubic splines. Avoidable burden of stillbirth under the predefined scenarios of improved greenness was estimated through a counterfactual analysis.

RESULTS

A total of 29,770 stillbirths occurred during 2013-2018, totaling to an overall annual rate of 748 cases per 100,000 births. Lower stillbirth risks were consistently seen in pregnant mothers being exposed to greater greenness within buffers of 500-3000 m. For instance, per 0.1-unit increase of NDVI and EVI within a 3000-m buffer was associated with the estimated odds of 0.971 (95 % confidence interval: 0.963-0.978) and 0.957 (0.947-0.968) for stillbirth, respectively. Evidently nonlinear relationships were identified between greenness exposure and stillbirth, exhibiting approximately an inverted L-shaped pattern with the steeper slope at high greenness levels. Assuming causality, 34-41 stillbirths per 100,000 births could be avoidable by achieving the 80th percentile of NDVI/EVI during 2013-2018, representing 4.6-5.4 % of nationwide registry-based stillbirths in Iran.

CONCLUSIONS

Our findings provided robust national evidence on beneficial effects of surrounding greenness in alleviating risk and burden of stillbirth in Iran, suggesting a greener environment could potentially serve as a promising intervention strategy for reducing stillbirth risk in less developed countries.

The impact of long-term exposure to NO2, O3, and their oxidative potential on adolescents' mental health, and the protective role of school-based greenness

Recent increases in nitrogen dioxide (NO2) and ozone (O3), two highly reactive and oxidative pollutants, have raised concerns about their potential impact on adolescent mental health. This study leveraged data from the Chinese National Survey on Students' Constitution and Health (CNSSCH) in 2019, a nationally representative cross-sectional survey of Chinese adolescents. A total of 149,697 adolescents aged 10-18 years were included in this study. NO2 and O3 were sourced from the ChinaHighAirPollutants dataset, and the combined oxidative potential (OX) was subsequently calculated using the concentrations of NO2 and O3. The study quantitively examined the association of NO2, O3, and OX with adolescent mental health using the Dual Factor Model of Mental Health (DFM), which was derived from a questionnaire. According to the DFM, mental health status was divided into four groups: complete mental health, vulnerable, symptomatic but content, and troubled. Greenness around schools, measured by the Normalized Difference Vegetation Index (NDVI), was examined for its potential effect modification on the association between NO2, O3, OX, and mental health. Each IQR (Interquartile Range) increase in OX was related to adverse mental health outcomes, with ORs of 1.17 (95 % CI: 1.06, 1.29) for being vulnerable, 1.20 (95 % CI: 1.12, 1.28) for being more symptomatic but content, and 1.15 (95 % CI: 1.07, 1.23) for being troubled. Similar findings emerged in relation to O3 exposure. A positive association was observed between NO2 exposure and being vulnerable (OR = 1.07; 95 % CI: 1.01, 1.16). Additionally, the impact of exposure to NO2, O3, and OX on mental health outcomes was significantly stronger in the low-level NDVI group compared to the high-level NDVI group (P for interaction < 0.05). The joint effects analysis revealed that adolescents exposed to high levels of air pollutants and low NDVI had the highest odds of adverse mental health outcomes. These results highlight the complex relationship between NO2, O3, OX, and mental health, with particular emphasis on the underexplored role of OX. Notably, the findings suggest that reducing pollution and increasing greenery could offer significant benefits for improving adolescent mental health.

Association between multiple metals exposure and metabolic dysfunction-associated fatty liver disease among Chinese adults

BACKGROUND

Previous research has investigated the hepatotoxicity of single metal exposure. However, there is limited evidence about metal mixture and their association with metabolic dysfunction-associated fatty liver disease (MAFLD), particularly in the Chinese population.

OBJECTIVE

To investigate the individual and combine effects of 20 metals on MAFLD in a large population in China.

METHODS

This study included 3651 participants from the Medical Physical Examination Center of Tongji Hospital, Wuhan, China. MAFLD was identified based on ultrasonic graphic evidence of hepatic steatosis and the presence of overweight/obese, diabetes mellitus, or metabolic dysregulation. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine urinary concentrations of 20 metals. Logistic regression was used to assess the relationship between individual metal and MAFLD, with results presented as odds ratios (ORs) and 95 % confidence intervals (CIs). Weighted quantile sum (WQS) regression was performed to evaluate the combine effect of metals.

RESULTS

The prevalence of MAFLD among the participants was 32.1 % (1173/3651). In singe-metal analysis, high exposure to zinc (OR =1.42; 95 % CI = 1.27, 1.59) and selenium (OR = 1.23; 95 % CI = 1.10, 1.39) were positively associated with MAFLD. No significant association was found for other metals. WQS regression analysis showed that urinary metal mixture was positively associated with MAFLD (OR = 1.32, 95 % CI: 1.15, 1.51), with zinc (50.4 %) being the largest contributor, followed by barium (10.8 %).

CONCLUSIONS

In conclusion, our finding suggested that exposure to the mixture of metals was positively correlated with MAFLD, with zinc being the major contributor.

Greenspace Morphology and Preterm Birth: A State-Wide Study in Georgia, United States (2001-2016)

BACKGROUND

Residential greenness is linked to birth outcomes. However, the role of greenspace morphology remains poorly understood. Additionally, evidence is lacking regarding whether these relationships vary by subpopulation.

OBJECTIVE

We examined the association between preterm birth and residential greenspace morphology, including percentage, shape, connectedness, aggregation, closeness, and fragmentation.

METHODS

We analyzed 2,063,444 singleton live births between 2001 to 2016 in Georgia, USA. Thirty-meter resolution landcover data from National Land Cover Databased (2001-2016) were obtained to calculate greenspace morphology metrics for 1,953 census tracts in Georgia. A two-stage logistic regression examined associations between each greenspace morphology metric and preterm birth at individual level. Stratified analysis was conducted by maternal race, ethnicity, education, urbanicity, poverty rate, and greenspace percentage.

RESULTS

Higher greenspace percentage, aggregation, closeness, shape complexity, connectedness, and lower fragmentation were linked to a lower risk of preterm birth. After adjusting for poverty rate, associations with morphology attenuated, except for fragmentation [odds ratio (OR) = 1.014; 95% confidence interval (CI): 1.0001, 1.026] across the entire population. Strongest associations were found among black mothers and in high-poverty areas. Specifically, the odds of preterm birth in the highest quartile of greenspace percentage were 0.962 (95% CI: 0.933, 0.991) times the odds in the lowest quartile. Additionally, a lower risk of preterm birth was associated with higher greenspace aggregation (OR = 0.969; 95% CI: 0.947, 0.992), and a higher risk of preterm birth was associated with higher fragmentation (OR = 1.028; 95% CI: 1.009, 1.047), both in the black mothers group. In tracts with a high poverty rate, a lower risk of preterm birth associate with higher greenspace percentage (OR = 0.953; 95% CI: 0.910, 0.999), aggregation (OR = 0.976; 95% CI: 0.955, 0.997), and lower fragmentation (OR = 0.976; 95% CI: 0.958, 0.994). The association with greenspace morphology was most pronounced in census tracts with a medium level of greenspace percentage.

DISCUSSION

Our study complements other studies by showing the importance and protective effects of greenspace morphology. The observed effects are particularly prominent in census tracts characterized by a moderate level of greenspace percentage, high poverty rates, and among black women. Our findings suggest the need for tailored greenspace planning strategies based on varying levels of greenness in different areas. For locations with low greenness, increasing the greenspace percentage may be prioritized. In areas with a medium level of greenness, strategic enhancement of greenspace morphology is recommended. For areas with high greenness, the focus should be on improving spatial closeness of greenspace. https://doi.org/10.1289/EHP14571.

Advancing research on greenspace and climate-sensitive adverse birth outcomes for equity and impact

Environmental epidemiologists are increasingly evaluating whether and how human exposure to vegetation (greenspace) can benefit health. Relatedly, scientists and policymakers have highlighted the need to integrate efforts to address the dual crises of accelerating climate change and rapid loss of biodiversity, including nature-based solutions. Greenspace is one solution that can protect humans from climate-related exposures, including heat, air pollution, and flooding. However, most environmental epidemiology research on greenspace occurs in high-income countries, and adverse birth outcomes, previously associated with greenspace, disproportionately occur in low- and middle-income countries (LMICs). Although epidemiology research using existing survey or administrative data and satellite imagery is important for documenting broad patterns, such research is lacking in LMICs. Further, complementary, community-engaged research to inform interventions and policies is needed so that nature-based solutions with co-benefits for climate mitigation and health are adopted effectively and equitably. We provide suggestions for future research that would increase impact and call for better representation of LMICs and vulnerable communities within high-income countries in research and action on greenspace and climate-sensitive birth outcomes.

Fine Particulate Matter, Its Constituents, and Spontaneous Preterm Birth

Importance

The associations of exposure to fine particulate matter (PM2.5) and its constituents with spontaneous preterm birth (sPTB) remain understudied. Identifying subpopulations at increased risk characterized by socioeconomic status and other environmental factors is critical for targeted interventions.

Objective

To examine associations of PM2.5 and its constituents with sPTB.

Design, Setting, and Participants

This population-based retrospective cohort study was conducted from 2008 to 2018 within a large integrated health care system, Kaiser Permanente Southern California. Singleton live births with recorded residential information of pregnant individuals during pregnancy were included. Data were analyzed from December 2023 to March 2024.

Exposures

Daily total PM2.5 concentrations and monthly data on 5 PM2.5 constituents (sulfate, nitrate, ammonium, organic matter, and black carbon) in California were assessed, and mean exposures to these pollutants during pregnancy and by trimester were calculated. Exposures to total green space, trees, low-lying vegetation, and grass were estimated using street view images. Wildfire-related exposure was measured by the mean concentration of wildfire-specific PM2.5 during pregnancy. Additionally, the mean exposure to daily maximum temperature during pregnancy was calculated.

Main Outcomes and Measures

The primary outcome was sPTB identified through a natural language processing algorithm. Discrete-time survival models were used to estimate associations of total PM2.5 concentration and its 5 constituents with sPTB. Interaction terms were used to examine the effect modification by race and ethnicity, educational attainment, household income, and exposures to green space, wildfire smoke, and temperature.

Results

Among 409 037 births (mean [SD] age of mothers at delivery, 30.3 [5.8] years), there were positive associations of PM2.5, black carbon, nitrate, and sulfate with sPTB. Adjusted odds ratios (aORs) per IQR increase were 1.15 (95% CI, 1.12-1.18; P < .001) for PM2.5 (IQR, 2.76 μg/m3), 1.15 (95% CI, 1.11-1.20; P < .001) for black carbon (IQR, 1.05 μg/m3), 1.09 (95% CI, 1.06-1.13; P < .001) for nitrate (IQR, 0.93 μg/m3), and 1.06 (95% CI, 1.03-1.09; P < .001) for sulfate (IQR, 0.40 μg/m3) over the entire pregnancy. The second trimester was the most susceptible window; for example, aORs for total PM2.5 concentration were 1.07 (95% CI, 1.05-1.09; P < .001) in the first, 1.10 (95% CI, 1.08-1.12; P < .001) in the second, and 1.09 (95% CI, 1.07-1.11; P < .001) in the third trimester. Significantly higher aORs were observed among individuals with lower educational attainment (eg, less than college: aOR, 1.16; 95% CI, 1.12-1.21 vs college [≥4 years]: aOR, 1.10; 95% CI, 1.06-1.14; P = .03) or income (<50th percentile: aOR, 1.17; 95% CI, 1.14-1.21 vs ≥50th percentile: aOR, 1.12; 95% CI, 1.09-1.16; P = .02) or who were exposed to limited green space (<50th percentile: aOR, 1.19; 95% CI, 1.15-1.23 vs ≥50th percentile: aOR, 1.12; 95% CI, 1.09-1.15; P = .003), more wildfire smoke (≥50th percentile: aOR, 1.19; 95% CI, 1.16-1.23 vs <50th percentile: aOR, 1.13; 95% CI, 1.09-1.16; P = .009), or extreme heat (aOR, 1.51; 95% CI, 1.42-1.59 vs mild temperature: aOR, 1.11; 95% CI, 1.09-1.14; P < .001).

Conclusions and Relevance

In this study, exposures to PM2.5 and specific PM2.5 constituents during pregnancy were associated with increased odds of sPTB. Socioeconomic status and other environmental exposures modified this association.

Causal evidence of the association between green and blue spaces (GBS) and maternal and neonatal health: a systematic review and meta-analysis protocol

INTRODUCTION

Previous systematic reviews investigating the effects of green and blue space (GBS) on maternal and neonatal health have mainly focused on cross-sectional evidence, limiting potential causal inferences. The last review on the topic was published in January 2024. This review focused on residential greenness effects and neonatal health only but did not include other green/blue space measures, or maternal health outcomes. This review also only included papers published up to June 2023; discounting the 15 studies that have been published since. Thus, this study will capture the growing number of studies that generate causal evidence and aims to investigate the association between GBS and maternal and/or neonatal health.

METHODS AND ANALYSIS

The study protocol was developed with reference to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. This review will include study designs such as experiments, quasi-experiments, longitudinal studies and more. The study independent variable must be a GBS, green space and/or blue space measure. Eligible maternal health outcomes are those reported during pregnancy and up to 1 year after pregnancy. Neonatal health outcomes are limited to neonates no older than 28 days. A total of seven online databases will be searched: Medline, Scopus, Web of Science, PsycInfo, Embase, Environment Complete, and Maternity and Infant Care Database. Abstract and full-text screenings will be undertaken by three reviewers. Risk of bias assessment will be conducted based on the Risk of Bias in Non-randomized Studies-of Exposure framework.A narrative synthesis will be undertaken. If sufficiently comparable studies are identified, meta-analyses using random effects models will be conducted. We will explore heterogeneity using the I2 test.

ETHICS AND DISSEMINATION

Ethical approval is not required as all the data will be derived from published primary studies that have already obtained ethical permissions. The findings will be disseminated through relevant conferences and peer-reviewed publications.

PROSPERO REGISTRATION NUMBER

CRD42023396372.

Pregnancy outcomes as related to in utero exposure to air pollution and greenness: The Life-GAP Project

Background

Lower birth weight and preterm birth may increase the risk of adverse health outcomes later in life. We examined whether maternal exposure to air pollution and greenness during pregnancy is associated with offspring birth weight and preterm birth.

Methods

We analyzed data on 4286 singleton births from 2358 mothers from Respiratory Health in Northern Europe, a prospective questionnaire-based cohort study (1990-2010). Mixed-effects regression models with random intercepts for mothers and centers were used to estimate the association of exposures to particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), ozone (O3), black carbon (BC), and greenness (Normalized Difference Vegetation Index in 300m-buffers [NDVI300m]) with birth outcomes, adjusting for potential confounders.

Results

Median (interquartile range [IQR]) exposures to PM2.5, PM10, NO2, O3, BC, and NDVI300m during pregnancy were 8.4(5.0) µg/m3, 14.4(8.3) µg/m3, 14.0(11.0) µg/m3, 54.7(10.2) µg/m3, 0.47(0.41) µg/m3, and 0.31(0.20), respectively. IQR increases in air pollution exposures during pregnancy were associated with decreased birth weight and the strongest association was seen for PM2.5 (-49g; 95% confidence interval [CI] = -83, -16). However, O3 showed an opposite association. IQR increase in NDVI300m was associated with an increase in birth weight of 25 g (95% CI = 7, 44). Preterm birth was not associated with the exposures.

Conclusion

Increased greenness and decreased air pollution may contribute to healthier pregnancies and improve overall health in the next generation. This emphasizes the need to adopt policies that target the reduction of air pollution emissions and exposure of the population.

Association of ambient ozone exposure and greenness exposure with hemorrhagic stroke mortality at different times: A cohort study in Shandong Province, China

Evidence on the association between long-term ozone exposure and greenness exposure and hemorrhagic stroke (HS) is limited, with mixed results. One potential source of this inconsistency is the difference in exposure time metrics. This study aimed to investigate the association between long-term exposure to ambient ozone, greenness, and mortality from HS using exposure metrics at different times. We also examined whether greenness exposure modified the relationship between ozone exposure and mortality due to HS. The study population consisted of 45771 participants aged ≥40 y residing in 20 counties in Shandong Province who were followed up from 2013 to 2019. Ozone exposure metrics (annual mean and warm season) and the normalized difference a measure of greenness exposure, were calculated. The relationship between environmental exposures (ozone and greenness exposures) and mortality from HS was assessed using time-dependent Cox proportional hazards models, and the modification of greenness exposure was examined using stratified analysis with interaction terms. The person-years at the end of follow-up were 90,663. With full adjustments, the risk of death from hemorrhagic stroke increased by 5% per interquartile range increase in warm season ozone [hazard ratio =1.05; 95 % confidence interval: 1.01-1.08]. No clear association was observed between annual ozone and mortality HS. Both the annual and summer NDVI were found to reduce the risk of HS mortality. The relationships were influenced by age, sex, and residence (urban or rural). Furthermore, greenness exposure was shown to have a modifying effect on the relationship between ozone exposure and the occurrence of HS mortality (P for interaction = 0.001). Long-term exposure to warm season O3 was positively associated with HS mortality, while greenness exposure was inversely associated with HS mortality. Greenness exposure may mitigate the negative effects of warm season ozone exposure on HS mortality.

Ambient Environment and the Epidemiology of Preterm Birth

Preterm birth (PTB) is associated with substantial mortality and morbidity. We describe environmental factors that may influence PTB risks. We focus on exposures associated with an individual's ambient environment, such as air pollutants, water contaminants, extreme heat, and proximities to point sources (oil/gas development or waste sites) and greenspace. These exposures may further vary by other PTB risk factors such as social constructs and stress. Future examinations of risks associated with ambient environment exposures would benefit from consideration toward multiple exposures - the exposome - and factors that modify risk including variations associated with the structural genome, epigenome, social stressors, and diet.

A cohort study of the multipollutant effects of PM2.5, NO2, and O3 on C-reactive protein levels during pregnancy

Background

PM2.5, NO2, and O3 contribute to the development of adverse pregnancy complications. While studies have investigated the independent effects of these exposures, literature on their combined effects is limited. Our objective was to study the multipollutant effects of PM2.5, NO2, and O3 on maternal systemic C-reactive protein (CRP) levels.

Methods

We used data from 1170 pregnant women enrolled in the Maternal-Infant Research on Environmental Chemicals Study (MIREC) study in Canada. Air pollution exposures were assigned to each participant based on residential location. CRP was measured in third-trimester blood samples. We fit multipollutant linear regression models and evaluated the effects of air pollutant mixtures (14-day averages) using repeated-holdout Weighted Quantile Sum (WQS) regression and by calculating the Air Quality Health Index (AQHI).

Results

In multipollutant models adjusting for NO2, O3, and green space, each interquartile range (IQR) increase in 14-day average PM2.5 (IQR: 6.9 µg/m3) was associated with 27.1% (95% confidence interval [CI] = 6.2, 50.7) higher CRP. In air pollution mixture models adjusting for green space, each IQR increase in AQHI was associated with 37.7% (95% CI = 13.9, 66.5) higher CRP; and an IQR increase in the WQS index was associated with 78.6% (95% CI = 29.7, 146.0) higher CRP.

Conclusion

PM2.5 has the strongest relationship of the individual pollutants examined with maternal blood CRP concentrations. Mixtures incorporating all three pollutants, assessed using the AQHI and WQS index, showed stronger relationships with CRP compared with individual pollutants and illustrate the importance of conducting multipollutant analyses.

Residential greenness and chronic obstructive pulmonary disease in a large cohort in southern China: Potential causal links, risk trajectories, and mediation pathways

INTRODUCTION

Residential greenness may influence COPD mortality, but the causal links, risk trajectories, and mediation pathways between them remain poorly understood.

OBJECTIVES

We aim to comprehensively identify the potential causal links, characterize the dynamic progression of hospitalization or posthospital risk, and quantify mediation effects between greenness and COPD.

METHODS

This study was conducted using a community-based cohort enrolling individuals aged ≥ 18 years in southern China from January 1, 2009 to December 31, 2015. Greenness was characterized by normalized difference vegetation index (NDVI) around participants' residential addresses. We applied doubly robust Cox proportional hazards model, multi-state model, and multiple mediation method, to investigate the potential causal links, risk trajectories among baseline, COPD hospitalization, first readmission due to COPD or COPD-related complications, and all-cause death, as well as the multiple mediation pathways (particulate matter [PM], temperature, body mass index [BMI] and physical activity) connecting greenness exposure to COPD mortality.

RESULTS

Our final analysis included 581,785 participants (52.52% female; average age: 48.36 [Standard Deviation (SD): 17.56]). Each interquartile range (IQR: 0.06) increase in NDVI was associated with a reduced COPD mortality risk, yielding a hazard ratio (HR) of 0.88 (95 % CI: 0.81, 0.96). Furthermore, we observed per IQR (0.04) increase in NDVI was inversely associated with the risk of multiple transitions (baseline - COPD hospitalization, baseline - death, and readmission - death risks), especially a declined risk of all-cause death after readmission (HR = 0.66 [95 %CI: 0.44, 0.99]). Within the observed association between greenness and COPD mortality, three mediators were identified, namely PM, temperature, and BMI (HR for the total indirect effect: 0.773 [95 % CI: 0.703, 0.851]), with PM showing the highest mediating effect.

CONCLUSIONS

Our findings revealed greenness may be a beneficial factor for COPD morbidity, prognosis, and mortality. This protective effect is primarily attributed to the reduction in PM concentration.

Joint effects of green space and air pollutant exposure on preterm birth: evidence from a nationwide study in China

An association between green space exposure and preterm birth has been reported. However, evidence on the joint effects of air pollutant and green space exposure on preterm birth from nationwide research is limited in China. Based on a nationwide cohort, this study aims to explore the effect of green space exposure on preterm birth and analyze the joint effects of green space and air pollutant. Logistic regression models were developed to analyze the effects of green space exposure, and interaction effects were evaluated by adding interaction terms between green space and air pollutants. From 2013 to 2019, this study included 2,294,188 records of newborn births, of which 82,921 were preterm births. The results show that for buffer zones with 250 m, 500 m, 1000 m, and 1500 m, every 0.1 unit increase in NDVI exposure was associated with a decrease in the risk of preterm birth by 5.5% (95% CI: 4.6-6.4%), 5.8% (95% CI: 4.9-6.6%), 6.1% (95% CI: 5.3-7.0%), and 5.6% (95% CI: 4.7-6.5%), respectively. Under high-level exposure to air pollutants, high-level NDVI exposure was more strongly negatively correlated with preterm birth than low-level NDVI exposure. High-level green space exposure might mitigate the adverse effect of air pollutants on preterm birth by promoting physical activity, reducing stress, and adsorbing pollutants. Further investigation is needed to explore how green space and air pollution interact and affect preterm birth, in order to improve risk management and provide a reference for newborn health.

Urban Green Space and Perinatal Health Inequities in the United States: A Literature Review

Access to urban green space has been linked to positive health outcomes including enhanced perinatal health. The purpose of this article was to review, summarize, and synthesize what is known about the relationship between urban green space and perinatal health and outline implications for practice, policy, education, and research. Nineteen articles were included in this state-of-the-science review. Overall, it was found that limited access to green space is significantly related to adverse birth outcomes. These findings present an important opportunity for childbirth educators and other clinicians involved in the provision of prenatal and reproductive health care. Through education and intervention, poor perinatal outcomes may be mitigated. Clinical screening and education about the importance of access to and use of urban green space during pregnancy should be an essential component of preconception counseling and antenatal screening for at-risk populations. Policy makers should be made aware of these findings so that impactful change can be made in order to reduce disparities and promote health equity.

Measuring Greenspace in Rural Areas for Studies of Birth Outcomes: A Comparison of Street View Data and Satellite Data

Using street view data, in replace of remotely sensed (RS) data, to study the health impact of greenspace has become popular. However, direct comparisons of these two methods of measuring greenspace are still limited, and their findings are inconsistent. On the other hand, almost all studies of greenspace focus on urban areas. The effectiveness of greenspace in rural areas remains to be investigated. In this study, we compared measures of greenspace based on the Google Street View data with those based on RS data by calculating the correlation between the two and evaluating their associations with birth outcomes. Besides the direct measures of greenness, we also compared the measures of environmental diversity, calculated with the two types of data. Our study area consists of the States of New Hampshire and Vermont, USA, which are largely rural. Our results show that the correlations between the two types of greenness measures were weak to moderate, and the greenness at an eye-level view largely reflects the immediate surroundings. Neither the street view data- nor the RS data-based measures identify the influence of greenspace on birth outcomes in our rural study area. Interestingly, the environmental diversity was largely negatively associated with birth outcomes, particularly gestational age. Our study revealed that in rural areas, the effectiveness of greenspace and environmental diversity may be considerably different from that in urban areas.

Critical windows of greenness exposure during preconception and gestational periods in association with birthweight outcomes

Few studies have examined the association between greenness exposure and birth outcomes. This study aims to identify critical exposure time windows during preconception and pregnancy for the association between greenness exposure and birth weight. A cohort of 13 890 pregnant women and newborns in Shanghai, China from 2016-2019 were included in the study. We assessed greenness exposure using Normalized Difference Vegetation Index (NDVI) during the preconception and gestational periods, and evaluated the association with term birthweight, birthweight z-score, small-for-gestational age, and large-for-gestational age using linear and logistic regressions adjusting for key maternal and newborn covariates. Ambient temperature, relative humidity, ambient levels of fine particles (PM2.5) and nitrogen dioxide (NO2) assessed during the same period were adjusted for as sensitivity analyses. Furthermore, we explored the potential different effects by urbanicity and park accessibility through stratified analysis. We found that higher greenness exposure at the second trimester of pregnancy and averaged exposure during the entire pregnancy were associated with higher birthweight and birthweight Z-score. Specifically, a 0.1 unit increase in second trimester averaged NDVI value was associated with an increase in birthweight of 10.2 g (95% CI: 1.8-18.5 g) and in birthweight Z-score of 0.024 (0.003-0.045). A 0.1 unit increase in an averaged NDVI during the entire pregnancy was associated with 10.1 g (95% CI: 1.0-19.2 g) increase in birthweight and 0.025 (0.001-0.048) increase in birthweight Z-score. Moreover, the associations were larger in effect size among urban residents than suburban residents and among residents without park accessibility within 500 m compared to those with park accessibility within 500 m. Our findings suggest that increased greenness exposure, particularly during the second trimester, may be beneficial to birth weight in a metropolitan area.

Disparities in the association between ambient temperature and preterm birth according to individual and regional characteristics: a nationwide time-stratified case-crossover study

BACKGROUND

Several studies have reported that climate change elevates heat exposure in pregnant women and high temperatures during pregnancy are associated with preterm births (PTBs). Although the association might be disproportionate, related evidence remains sparse. We evaluated the disproportionate risk of PTB associated with ambient temperature during pregnancy by individual and regional characteristics in South Korea.

METHODS

We collected data on birth certificates and daily mean temperatures during the period from 2011 to 2019. A time-stratified case-crossover design was used to investigate the association between temperature and PTB and stratified analyses were conducted to examine the effect modification of individual and regional characteristics.

RESULTS

A total of 160,067 singleton PTBs were recorded in Korea from 2011 to 2019. A 5℃ increase in the mean temperature during the last four weeks before delivery was associated with an increased risk of PTB with an odds ratio (OR) of 1.03 (95% confidence interval [CI]: 1.02, 1.05), and the association was more evident in mothers aged ≥35 years (OR: 1.06 [95% CI: 1.03, 1.10]) and with low education levels (OR: 1.04 [95% CI: 1.02, 1.05]). Additionally, the estimated risk was evident in districts with lower medical resources and more prominent disparities were shown by individual and regional characteristics in rural areas than in urban areas.

CONCLUSIONS

This study provides evidence that the risk of PTB related to ambient temperature is disproportionate by individual and regional characteristics and suggests the need for public health policies to alleviate the disparities, especially in rural areas.

Association of residential greenness, air pollution with adverse birth outcomes: Results from 61,762 mother‑neonatal pairs in project ELEFANT (2011-2021)

BACKGROUND

Emerging evidence has demonstrated the benefits of greenness exposure on human health, while conflicts remain unsolved in issue of adverse birth outcomes.

METHODS

Utilizing data from project ELEFANT spanning the years 2011 to 2021, we assessed residential greenness using the NDVI from MODIS data and residential PM2.5 exposure level from CHAP data. Our primary concerns were PTD, LBW, LGA, and SGA. Cox proportional hazard regression model was used to examine the association of residential greenness and air pollution exposure with risk of adverse birth outcomes. We performed mediation and modification effect analyses between greenness and air pollutant.

RESULTS

We identified 61,762 mother‑neonatal pairs in final analysis. For per 10 μg/m3 increase in PM2.5 concentration during entire pregnancy was associated with 19.8 % and 20.7 % increased risk of PTD and LGA. In contrast, we identified that an 0.1 unit increment in NDVI were associated with 24 %, 43 %, 26.5 %, and 39.5 % lower risk for PTD, LBW, LGA, and SGA, respectively. According to mediation analysis, NDVI mediated 7.70 % and 7.89 % of the associations between PM2.5 and PTD and LGA. Residential greenness could reduce the risk of PTD among mothers under 35 years old, living in rural areas, primigravidae and primiparity..

CONCLUSIONS

In summary, our results highlighted the potential of residential greenness to mitigate the risk of adverse birth outcomes, while also pointing to the adverse impact of PM2.5 on increased risk of multiple adverse birth outcomes (PTD and LGA). The significant mediation effect of NDVI emphasizes its potential as an important protective factor of PM2.5 exposure. Additionally, the identification of susceptible subgroups can inform targeted interventions to reduce adverse birth outcomes related to air pollution and lack of green spaces. Further research and understanding of these associations can contribute to better public health strategies aimed at promoting healthier pregnancies and birth outcomes.

Maternal greenness exposure and preterm birth in Brazil: A nationwide birth cohort study

In the dynamic landscape of maternal and child health, understanding the intricate interplay between environmental factors and pregnancy outcomes is of paramount importance. This study investigates the relationship between maternal greenness exposure and preterm births in Brazil using data spanning from 2010 to 2019. Satellite-derived indices, including the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), were employed to assess greenness exposure during whole pregnancy in maternal residential area. Employing Cox proportional hazard models, we calculated the hazard ratios (HRs) with 95% confidence intervals (CIs) for changes in NDVI, while adjusting for individual and area-level covariates. In total, 24,010,250 live births were included. Prevalence of preterm birth was 11.5%, with a modest but statistically significant decreasing trend (p = 0.013) observed across the nation over the study period. The findings reveal a significant association between greenness exposure and a reduced risk of preterm birth. Specifically, for every 0.1 increase in NDVI, there was a 2.0% decrease in the risk of preterm birth (95%CI: 1.9%-2.2%). Stratified analyses based on maternal education and ethnicity indicated potential effect modifications, with stronger protective effects observed among younger mothers and those with less years of education. Sensitivity analyses using EVI yielded consistent results. In conclusion, this study suggests that higher maternal greenness exposure is linked to a decreased risk of preterm birth in Brazil. These findings imply that enhancing residential greenspaces could be a valuable public health strategy to promote maternal and child health in Brazil.

Estimating changes in inequality of ecosystem services provided by green exposure: From a human health perspective

Ecosystem services provided by green spaces are closely related to human health, strongly supporting sustainable urban and territorial development. Urbanization has not only resulted in the reduction of green spaces but has also created inequalities in exposure. Inequitable green exposure creates disparities in residents' access to the ecosystem services provided by green spaces and can lead to significant health inequities. In this context, we first categorized green exposures into active and passive types based on their characteristics. Second, utilizing the benefit transfer method and Gini coefficient, we estimated the value and equity of ecosystem services offered by these green exposures around residences at the municipality level in Japan from 2000 to 2020, with a focus on human health implications. Finally, we explored the potential relationship between socioeconomics and ecosystem service inequity. Our findings reveal that: 1) ecosystem service value per capita and equity provided by green exposure are significantly different across municipalities; 2) although most municipalities show an upward trend in per capita ecosystem service value around residences, ecosystem service inequity increases significantly; and 3) ecosystem service inequity is related to the socioeconomic factors of municipalities and could be non-linear. The results of this study suggest that the government should adopt indicators related to the ecosystem services provided by green exposure during urban planning. While focusing on per-capita ecosystem services, they should also consider the equitable distribution of ecosystem services to promote sustainable urban health development.

The adverse impact of maternal ozone exposure on fetal growth in utero and the interaction with residential greenness

This study aimed to investigate the effect of maternal ozone exposure on fetal growth during pregnancy, as well as the combined effect and interaction of ozone and residential greenness. We included a total of 14990 singleton pregnancies from the Fujian Birth Cohort Study. During pregnancy, fetal growth parameters including estimated fetal weight (EFW), femur length (FL), head circumference (HC), and abdominal circumference (AC). To investigate the associations between ozone exposure and the above-mentioned outcomes, generalized estimating equation approach and generalized linear regression were used, as appropriate. In the adjusted models, we observed that the Z scores of EFW (-0.031 (-0.048, -0.014)), FL (-0.021 (-0.038, -0.004)), and AC (-0.025 (-0.042, -0.007)) decreased with per interquartile range (IQR) increase of ozone concentration. Compared to participants with low ozone exposure and high NDVI, those with high ozone exposure and low NDVI experienced the largest decrease in Z scores for EFW (-0.049 (-0.079, -0.02)), FL (-0.034 (-0.063, -0.004)), HC (-0.034 (-0.065, -0.004)), and AC (-0.041 (-0.072, -0.01)), respectively. Interestingly, we discovered the effect modification of NDVI on the relationship between ozone exposure and fetal growth restriction (P for interaction < 0.05). This study established a negative relationship of maternal ozone exposure and fetal growth. Of importance, this study discovered the joint effect and interaction between ozone and residential greenness exposure.

Racial and Ethnic Disparities in Phthalate Exposure and Preterm Birth: A Pooled Study of Sixteen U.S. Cohorts

BACKGROUND

Phthalate exposures are ubiquitous during pregnancy and may contribute to racial and ethnic disparities in preterm birth.

OBJECTIVES

We investigated race and ethnicity in the relationship between biomarkers of phthalate exposure and preterm birth by examining: a) how hypothetical reductions in racial and ethnic disparities in phthalate metabolites might reduce the probability of preterm birth; and b) exposure-response models stratified by race and ethnicity.

METHODS

We pooled individual-level data on 6,045 pregnancies from 16 U.S. cohorts. We investigated covariate-adjusted differences in nine urinary phthalate metabolite concentrations by race and ethnicity [non-Hispanic White (White, 43%), non-Hispanic Black (Black, 13%), Hispanic/Latina (38%), and Asian/Pacific Islander (3%)]. Using g-computation, we estimated changes in the probability of preterm birth under hypothetical interventions to eliminate disparities in levels of urinary phthalate metabolites by proportionally lowering average concentrations in Black and Hispanic/Latina participants to be approximately equal to the averages in White participants. We also used race and ethnicity-stratified logistic regression to characterize associations between phthalate metabolites and preterm birth.

RESULTS

In comparison with concentrations among White participants, adjusted mean phthalate metabolite concentrations were consistently higher among Black and Hispanic/Latina participants by 23%-148% and 4%-94%, respectively. Asian/Pacific Islander participants had metabolite levels that were similar to those of White participants. Hypothetical interventions to reduce disparities in metabolite mixtures were associated with lower probabilities of preterm birth for Black [13% relative reduction; 95% confidence interval (CI): - 34 % , 8.6%] and Hispanic/Latina (9% relative reduction; 95% CI: - 19 % , 0.8%) participants. Odds ratios for preterm birth in association with phthalate metabolites demonstrated heterogeneity by race and ethnicity for two individual metabolites (mono-n-butyl and monoisobutyl phthalate), with positive associations that were larger in magnitude observed among Black or Hispanic/Latina participants.

CONCLUSIONS

Phthalate metabolite concentrations differed substantially by race and ethnicity. Our results show hypothetical interventions to reduce population-level racial and ethnic disparities in biomarkers of phthalate exposure could potentially reduce the probability of preterm birth. https://doi.org/10.1289/EHP12831.

Residential mobility in pregnancy and potential exposure misclassification of air pollution, temperature, and greenness

Introduction

Epidemiological studies commonly use residential addresses at birth to estimate exposures throughout pregnancy, ignoring residential mobility. Lack of consideration for residential mobility during pregnancy might lead to exposure misclassification that should be addressed in environmental epidemiology.

Methods

We investigated potential exposure misclassification from estimating exposure during pregnancy by residence at delivery utilizing a prospective cohort of pregnant women in New York, United States (n = 1899; 2016-2019). We calculated exposure during pregnancy corresponding to each address for fine particles (PM2.5), temperature, and greenness (Enhanced Vegetation Index [EVI]).

Results

Twenty-two percent of participants moved at least once during pregnancy; 82.3% of movers changed residences during the second or third trimesters. Participants with better health, lower parity, and higher socioeconomic status were more likely to move. Exposures based on address at delivery rather than residential history overestimated exposure for PM2.5 (exposure error: range -5.7 to 4.6 µg/m3, average -0.6 µg/m3) and EVI (range -0.305 to 0.307, average -0.013), but not temperature. Overestimations were significantly larger for mothers with higher socioeconomic status. Our findings indicate that the error for prenatal exposure can occur when residential mobility is not considered and is disproportional by maternal characteristics.

Conclusions

Epidemiological studies should consider residential mobility in exposure assessments based on geolocation when possible, and results based on mother's residence at birth should be interpreted with understanding of potential differential exposure misclassification.

Association between residential greenness and severe psychological distress and the moderating role of 'stay-at-home' status: a population-based cross-sectional study during the COVID-19 pandemic in Japan

Objective

There is a need for public health strategies to address the negative psychological consequences of the COVID-19 pandemic, and the role of residential green exposure has gained prominence, particularly in the context of the 'new normal' and the prevailing 'stay-at-home' policies. This study aimed to evaluate the association between residential greenness and severe psychological distress during the COVID-19 pandemic in Japan. We also investigated the association stratified by 'stay-at-home' status, a proxy for exposure to residential greenness.

Methods and analysis

We used data from a population-based cohort study conducted in Utsunomiya City, Japan. Residential greenness was measured by the normalised difference vegetation index (NDVI) averaged over circular buffers around residence. Severe psychological distress was defined as a Kessler Psychological Distress Scale (K6) score ≥13. 'Stay-at-home' status was categorised as either 'not stay-at-home' (individuals working outside the home or self-employed) or 'stay-at-home' (working from home or not working), based on the working status. Logistic regression analysis was performed to examine the association between residential greenness and severe psychological distress.

Results

A total of 615 participants were analysed. Among the 'stay-at-home' group, an IQR increase in NDVI was inversely associated with severe psychological distress (100 m buffer: OR=0.27, 95% CI 0.10 to 0.77; 250 m buffer: OR=0.26, 95% CI 0.10 to 0.69; 500 m buffer: OR=0.33, 95% CI 0.11 to 0.95). However, no significant association was observed for the 'not stay-at-home' group.

Conclusion

Residential greenness was a protective factor for severe psychological distress among the 'stay-at-home' group, who were assumed to have spent more time in their residence.

Residential greenspace counteracts PM2.5 on the risks of preterm birth subtypes: A multicenter study

BACKGROUND

The association between residential greenspace and preterm birth (PTB) risk remained inconclusive. The PTB subtypes have been ignored and the effect of co-exposure of PM2.5 on PTB risk is still unclear.

OBJECTIVE

To investigate the independent, interactive, and mixed effects of residential greenspace and PM2.5 on the risk of PTB subtypes.

METHODS

A total of 19,900 singleton births from 20 hospitals in Shanghai, China, from 2015 to 2017 were included. The Normalized Difference Vegetation Index (NDVI) within 500 m and 1000 m buffers of the maternal residence and a combined geoscience-statistical model-derived PM2.5 and its six components were used as the exposure measures. PTB (<37 completed weeks of gestation) were divided into early PTB (24-33 weeks) vs. late PTB (34-36 weeks) and into spontaneous PTB (sPTB), preterm premature rupture of the fetal membranes (PPROM), and iatrogenic PTB. Multivariable logistic regression models were applied to assess the independent and interactive effects of NDVI and PM2.5 on PTB in each trimester. The quantile g-computation approach was employed to explore the mixture effect of PM2.5 components and greenspace across the pregnancy and to determine the main contributors.

RESULTS

Levels of PM2.5 and greenspace were associated with increased [aOR (95%CI) ranging from 1.18 (1.07, 1.30) to 3.36 (2.45, 4.64)] and decreased risks [aORs (95%CI) ranging from 0.64 (0.53, 0.78) to 0.86 (0.73, 0.99)] of PTB subtypes, respectively. At the same PM2.5 level, higher residential greenspace was associated with lower risks, and vice versa. All these associations were more pronounced in late pregnancy. Early PTB and PPROM were the main affected subtypes, and the main drivers in PM2.5 were black carbon and ammonium.

CONCLUSIONS

Residential greenspace may mitigate the PTB risks due to PM2.5 exposure during pregnancy.

Place-Based Strategies Addressing Neighborhood Environments to Improve Perinatal and Preterm Infant Outcomes

Preterm birth (defined as birth <37 weeks of gestation) is a significant health concern globally, with lasting implications for individuals, families, and society. In the United States, high preterm birth rates among Black and low-income populations likely result from differences in environmental exposures. Structural racism and economic disadvantage have led to unequal distribution of polluting industrial sites and roadways across society as well as differential access to health-promoting resources which contribute to preterm birth risk. Once born, preterm infants remain at risk for numerous environmentally responsive adverse health outcomes that affect growth and development throughout childhood and adulthood. In this commentary, we describe associations of neighborhood environments with pregnancy and preterm infant health outcomes and propose strategies to address harmful exposures that affect families across the lifespan.

Changes in Residential Greenspace and Birth Outcomes among Siblings: Differences by Maternal Race

Growing research investigates the perinatal health benefits of greenspace in a mother's prenatal environment. However, evidence of associations between residential greenspace and birth outcomes remains mixed, limiting the relevance this work holds for urban policy and greening interventions. Past research relies predominantly on cross-sectional designs that are vulnerable to residential selection bias, and rarely tests effect modification by maternal race/ethnicity, which may contribute to heterogeneous findings. This study uses a rigorous, longitudinal sibling comparison design and maternal fixed effect analyses to test whether increases in maternal exposure to residential greenspace between pregnancies precede improved birth outcomes among non-Hispanic (NH) white (n = 247,285) and Black (n = 54,995) mothers (mean age = 28 years) who had at least two consecutive live births in California between 2005 and 2015. Results show that increases in residential greenspace correspond with higher birthweight (coef. = 75.49, 95% CI: 23.48, 127.50) among Black, but not white (coef. = -0.51, 95% CI: -22.90, 21.90), infants. Additional analyses suggest that prior evidence of perinatal benefits associated with residential greenspace among white mothers may arise from residential selection; no such bias is observed for Black mothers. Taken together, these findings support urban greening initiatives in historically under-resourced neighborhoods. Efforts to evenly distribute residential greenspace may reduce persistent racial disparities in birth outcomes, an important step towards promoting health equity across the life course.

The impact of place-based contextual social and environmental determinants on preterm birth: A systematic review of the empirical evidence

The objective of this study was to systematically review the available empirical evidence examining associations between preterm birth (PTB) and five domains of place-based contextual social and environmental determinants, including (1) physical environment, (2) residential greenness, (3) neighborhood violence/crime, (4) food accessibility and availability, and (5) health services accessibility, among adult mothers in high-income countries. The evidence in this review suggests an adverse association between damaged physical environment, neighborhood violence/crime, lack of health services accessibility, and PTB. The existing evidence also suggests a beneficial effect of residential greenness on PTB. Further studies are needed to investigate these associations for more understanding of the direction and magnitude of these association and for potential heterogeneity by factors such as race/ethnicity, urban vs rural residence, immigration status, and social class.

Maternal exposure to ambient air pollution mixture and premature rupture of membranes: Evidence from a large cohort in Southern California (2008-2018)

BACKGROUND

There is minimal evidence of relationships between maternal air pollution exposure and spontaneous premature rupture of membranes (SPROM), a critical obstetrical problem that can significantly increase maternal and fetal mortality and morbidity. No prior study has explored the PROM risk related to specific components of particulate matter with aerodynamic diameters of ≤ 2.5 µm (PM2.5). We examined associations between maternal exposure to nitrogen dioxide (NO2), ozone (O3), PM2.5, PM10, and PM2.5 constituents and SPROM.

METHODS

A large retrospective cohort study was conducted and included 427,870 singleton live births from Kaiser Permanente Southern California during 2008-2018. Monthly averages of NO2, O3 (8-h daily maximum), PM2.5, and PM10 were measured using empirical Bayesian kriging based on measurements from monitoring stations. Data on PM2.5 sulfate, nitrate, ammonium, organic matter, and black carbon were obtained from a fine-resolution model. A discrete time approach with pooled logistic regressions was used to estimate associations throughout the pregnancy and based on trimesters and gestational months. The quantile-based g-computation models were fitted to examine the effects of 1) the air pollution mixture of four pollutants of interest and 2) the mixture of PM2.5 components.

RESULTS

There were 37,857 SPROM cases (8.8%) in our study population. We observed relationships between SPROM and maternal exposure to NO2, O3, and PM2.5. PM2.5 sulfate, nitrate, ammonium, and organic matter were associated with higher SPROM risks in the single-pollutant model. Mixture analyses demonstrated that the overall effects of the air pollution mixture and PM2.5 mixture in this study were mainly driven by O3 and PM2.5 nitrate, respectively. Underweight mothers had a significantly higher risk of SPROM associated with NO2.

CONCLUSION

Our findings add to the literature on associations between air pollution exposure and SPROM. This is the first study reporting the impact of PM2.5 constituents on SPROM.

Association between urban green space and postpartum depression, and the role of physical activity: a retrospective cohort study in Southern California

Background

Little research exists regarding the relationships between green space and postpartum depression (PPD). We aimed to investigate the relationships between PPD and green space exposure, and the mediating role of physical activity (PA).

Methods

Clinical data were obtained from Kaiser Permanente Southern California electronic health records in 2008-2018. PPD ascertainment was based on both diagnostic codes and prescription medications. Maternal residential green space exposures were assessed using street view-based measures and vegetation types (i.e., street tree, low-lying vegetation, and grass), satellite-based measures [i.e., Normalized Difference Vegetation Index (NDVI), land-cover green space, and tree canopy cover], and proximity to the nearest park. Multilevel logistic regression was applied to estimate the association between green space and PPD. A causal mediation analysis was performed to estimate the proportion mediated by PA during pregnancy in the total effects of green space on PPD.

Findings

In total, we included 415,020 participants (30.2 ± 5.8 years) with 43,399 (10.5%) PPD cases. Hispanic mothers accounted for about half of the total population. A reduced risk for PPD was associated with total green space exposure based on street-view measure [500 m buffer, adjusted odds ratio (OR) per interquartile range: 0.98, 95% CI: 0.97-0.99], but not NDVI, land-cover greenness, or proximity to a park. Compared to other types of green space, tree coverage showed stronger protective effects (500 m buffer, OR = 0.98, 95% CI: 0.97-0.99). The proportions of mediation effects attributable to PA during pregnancy ranged from 2.7% to 7.2% across green space indicators.

Interpretation

Street view-based green space and tree coverage were associated with a decreased risk of PPD. The observed association was primarily due to increased tree coverage, rather than low-lying vegetation or grass. Increased PA was a plausible pathway linking green space to lower risk for PPD.

Funding

National Institute of Environmental Health Sciences (NIEHS; R01ES030353).

Greenness modifies the association between ambient air pollution and cognitive function in Australian adolescents, but not in mid-life adults

Exposure to ambient air pollution has been associated with reduced cognitive function in childhood and later life, with too few mid-life studies to draw conclusions. In contrast, residential greenness has been associated with enhanced cognitive function throughout the lifecourse. Here we examine the extent to which (1) ambient air pollution and residential greenness predict later cognitive function in adolescence and mid-life, and (2) greenness modifies air pollution-cognitive function associations.

PARTICIPANTS

6220 adolescents (51% male) and 2623 mid-life adults (96% mothers) from the Longitudinal Study of Australian Children.

MEASURES

Exposures: Annual average particulate matter <2.5 μm (PM_2.5), nitrogen dioxide (NO₂) and greenness (Normalised Difference Vegetation Index) for residential addresses from validated land-use regression models over a 10-13-year period.

OUTCOMES

Cognitive function from CogState tests of attention, working memory and executive function, dichotomised into poorer (worst quartile) versus not poor.

ANALYSES

Adjusted mixed-effects generalised linear models with residential greenness assessed as an effect modifier (high vs. low divided at median). The annual mean for PM_2.5 and NO₂ across exposure windows was 6.3-6.8 μg/m³, and 5.5-7.1 ppb, respectively. For adolescents, an IQR increment of NO₂ was associated with 19-24% increased odds of having poorer executive function across all time windows, while associations weren't observed between air pollution and other outcomes. For adults, high NO₂ predicted poorer cognitive function across all outcomes, while high PM_2.5 predicted poorer attention only. There was little evidence of associations between greenness and cognitive function in adjusted models for both generations. Interactions were found between residential greenness, air pollutants and cognitive function in adolescents, but not adults. The magnitude of effects was similar across generations and exposure windows. Findings highlight the potential benefits of cognitive health associated with the regulation of air pollution and urban planning strategies for increasing green spaces and vegetation.

The role of extreme heat exposure on premature rupture of membranes in Southern California: A study from a large pregnancy cohort

BACKGROUND

Significant mortality and morbidity in pregnant women and their offspring are linked to premature rupture of membranes (PROM). Epidemiological evidence for heat-related PROM risk is extremely limited. We investigated associations between acute heatwave exposure and spontaneous PROM.

METHODS

We conducted this retrospective cohort study among mothers in Kaiser Permanente Southern California who experienced membrane ruptures during the warm season (May-September) from 2008 to 2018. Twelve definitions of heatwaves with different cut-off percentiles (75th, 90th, 95th, and 98th) and durations (≥ 2, 3, and 4 consecutive days) were developed using the daily maximum heat index, which incorporates both daily maximum temperature and minimum relative humidity in the last gestational week. Cox proportional hazards models were fitted separately for spontaneous PROM, term PROM (TPROM), and preterm PROM (PPROM) with zip codes as the random effect and gestational week as the temporal unit. Effect modification by air pollution (i.e., PM2.5 and NO2), climate adaptation measures (i.e., green space and air conditioning [AC] penetration), sociodemographic factors, and smoking behavior was examined.

RESULTS

In total, we included 190,767 subjects with 16,490 (8.6%) spontaneous PROMs. We identified a 9-14% increase in PROM risks associated with less intense heatwaves. Similar patterns as PROM were found for TPROM and PPROM. The heat-related PROM risks were greater among mothers exposed to a higher level of PM2.5 during pregnancy, under 25 years old, with lower education and household income level, and who smoked. Even though climate adaptation factors were not statistically significant effect modifiers, mothers living with lower green space or lower AC penetration were at consistently higher heat-related PROM risks compared to their counterparts.

CONCLUSION

Using a rich and high-quality clinical database, we detected harmful heat exposure for spontaneous PROM in preterm and term deliveries. Some subgroups with specific characteristics were more susceptible to heat-related PROM risk.

Outdoor artificial light at night, air pollution, and risk of childhood acute lymphoblastic leukemia in the California Linkage Study of Early-Onset Cancers

Acute lymphoblastic leukemia (ALL) is the most common type of cancer in children (age 0-14 years); however, the etiology remains incompletely understood. Several environmental exposures have been linked to risk of childhood ALL, including air pollution. Closely related to air pollution and human development is artificial light at night (ALAN), which is believed to disrupt circadian rhythm and impact health. We sought to evaluate outdoor ALAN and air pollution on risk of childhood ALL. The California Linkage Study of Early-Onset Cancers is a large population-based case-control in California that identifies and links cancer diagnoses from the California Cancer Registry to birth records. For each case, 50 controls with the same year of birth were obtained from birth records. A total of 2,782 ALL cases and 139,100 controls were identified during 2000-2015. ALAN was assessed with the New World Atlas of Artificial Night Sky Brightness and air pollution with an ensemble-based air pollution model of particulate matter smaller than 2.5 microns (PM2.5). After adjusting for known and suspected risk factors, the highest tertile of ALAN was associated with an increased risk of ALL in Hispanic children (odds ratio [OR] = 1.15, 95% confidence interval [CI] 1.01-1.32). There also appeared to be a borderline association between PM2.5 level and risk of ALL among non-Hispanic White children (OR per 10 µg/m3 = 1.24, 95% CI 0.98-1.56). We observed elevated risk of ALL in Hispanic children residing in areas of greater ALAN. Further work is needed to understand the role of ALAN and air pollution in the etiology of childhood ALL in different racial/ethnic groups.

Green space, air pollution and gestational diabetes mellitus: A retrospective cohort study in central China

Emerging evidence suggests residential surrounding green space is beneficial for human health. The association between green space and GDM showed inconsistent results, and potential effect modification of green space with air pollution is still unclear. This study aims to evaluate the association between green space and GDM, and further explore potential interaction and medication effects. Participants were recruited from a retrospective cohort study between 2015 and 2020 in Henan, China. Residential green space based on normalized difference vegetation index (NDVI) and air pollution exposure were estimated using spatial-statistical models. Multivariate logistic regression was applied to evaluate the association between per 0.1 unit increase in NDVI with 4 buffer sizes (250 m, 500 m, 1000 m, 2000 m) and GDM. We examined potential interaction of green space and air pollutants on GDM. Mediating effects of air pollution associated with green space exposure on GDM were also investigated by causal mediation analyses. A total of 46,665 eligible pregnant women were identified. There were 4092 (8.8 %) women diagnosed with GDM according to the IADPSG criteria. We found that per 0.1-unit increment in NDVI250 m, NDVI500 m, NDVI1000 m and NDVI2000 m in second trimester were associated with the decreased risk of GDM, with adjusted OR of 0.921(95 %CI: 0.890-0.953), 0.922 (95 %CI: 0.891-0.953), 0.921 (95 %CI: 0.892-0.952) and 0.921 (95 %CI: 0.892-0.951), respectively. We identified significant interactions between second trimester PM2.5 and O3 exposure and NDVI for GDM (Pinteraction < 0.001). The causal mediation analysis showed that PM2.5 mediated approximately 2.5-5.5 % of the association between green space and GDM, while the estimated mediating effect of O3 was approximately 30.1-38.5 %. In conclusion, our study indicates that residential green space was associated with a reduced risk of GDM, particularly second trimester. Green space may benefit to GDM partly mediated by a reduction in PM2.5 and O3.

Interaction effects of night-time temperature and PM2.5 on preterm birth in Huai River Basin, China

Nocturnal temperature is observed increasing with global warming. However, evidence on night-time non-optimal temperature on the risk of preterm birth (PTB) is limited, and the potential interactions with air pollution on PTB has not been well clarified. We therefore conducted a population-based retrospective cohort study to evaluate the effect of night-time temperature extremes on the risk of PTB and its interaction with air pollution. Records of 196,780 singleton births from 4 counties in Huai River Basin (2013-2018) were obtained. Gridded data on night-time temperature were collected from a high-quality Chinese Air Quality Reanalysis dataset. We used a multivariate logistic regression to evaluate the effects of night-time heat and cold exposure on the risk of PTB as well as its subtypes. Potential interactions between night-time temperature extremes and fine particulate matter < 2.5 µm (PM_2.5) were examined using the relative excess risk due to interaction (RERI). We found that the risk of PTB was positively associated with third trimester night-time extremely heat and cold exposure, with adjusted OR of 1.898 (95 %CI: 1.655-2.177) and 2.044 (95 %CI: 1.786-2.339). Similar effects were observed for PTB subtypes, moderately PTB (mPTB) and very PTB (vPTB). Synergistic effects (RERI greater than 0) of each trimester night-time temperature extremes exposure and PM_2.5 on PTB were observed. We identified consistent positive interactions between night-time temperature extremes and PM_2.5 on mPTB. No significant interaction of night-time temperature extremes and PM_2.5 on vPTB was found. In conclusion, this large retrospective cohort study found that third trimester night-time heat and cold exposure significantly increased the risk of PTB and its subtypes. There is a synergistic effect between night-time temperature extremes and high PM_2.5 levels on PTB and mPTB. In the context of climate warming, our results add new evidence to the current understanding of night-time non-optimal temperature exposure on PTB.

Physiological and affective responses to green space virtual reality among pregnant women

BACKGROUND

Benefits of green spaces on stress reduction have been shown in previous studies. Most existing studies to date have focused on the general population. However, there is a lack of understanding of physiological mechanisms underlying the beneficial effects of green space among special populations, such as pregnant women.

OBJECTIVES

To examine physiological and affective responses to green space on stress recovery among pregnant women, using simulated green space exposure through virtual reality (VR).

METHODS

We recruited 63 pregnant women between 8 and 14 weeks' gestational age for a laboratory experiment. Participants were randomly assigned to view one of three, 5-min, VR videos of an urban scene with different green space levels (i.e., non-green, moderate, and high) after a laboratory stressor, the Trier Social Stress Test. Physiological stress responses were measured via changes in blood pressure, heart rate, skin conductance level, salivary alpha-amylase, and salivary cortisol. Affective response was measured using the Positive and Negative Affect Scale.

RESULTS

We found that visual exposure to a green space environment in VR was associated with both physiological and affective stress reduction among pregnant women, including lower systolic blood pressure [-4.6 mmHg, 95% confidence interval (CI): -8.8, -0.4], reduced salivary alpha-amylase concentration (-1.2 ng/ml, 95% CI: -2.2, -0.2), improved overall positive affect (score: 6.6, 95% CI: 0.3, 13.0) and decreased negative affect of anxiety (score: -2.6, 95% CI: -5.19, -0.04) compared to non-green space environment. Exposure to high green space environment in park-like setting had the strongest impacts on stress recovery.

CONCLUSION

This study demonstrated that virtual green space exposure could effectively ease stress and improve mental health and well-being during pregnancy. Even a short immersion in VR-based green space environment may bring health benefits, which has significant implications for pregnant women when access to an actual nature may not be possible.

Changing trends in the air pollution-related disease burden from 1990 to 2019 and its predicted level in 25 years

In the twenty-first century, exposure to air pollution has become a threat to human health worldwide due to industrial development. Timely, comprehensive, and reliable assessment and prediction of disease burden can help mitigate the health hazards of air pollution. This study conducted a two-stage analysis. First, we reported the air pollution-related disease burden globally and for different subgroups like socio-demographic index (SDI), sex, and age. We analyzed the trend of the disease burden from 1990 to 2019. In addition, we explored whether and how some national indicators modified the disease burden. Second, we predicted the number and the age-standardized rates of death and disability-adjusted life years (DALYs) attributable to air pollution from 2020 to 2044 by the autoregressive integrated moving average (ARIMA) model and exponential smoothing model. The age-period-cohort (APC) model in the maximum likelihood framework and the Bayesian APC model integrated nested Laplace approximations (INLAs) were further applied to perform sensitivity analysis. In 2019, air pollution accounted for 11.62% of death and 0.84% of DALY worldwide. The corresponding age-standardized rate was 85.62 (95% uncertainty interval (UI): 75.71, 96.07) and 2791.08 (95% UI: 2468.81, 3141.39) per 100,000 population. From 1990 to 2019, the number of death attributable to air pollution remained stable, and the number of DALY exhibited a downward trend. The corresponding age-standardized rates both declined. In some countries with larger population densities, higher proportions of elders, and lower proportions of females, the disease burden attributable to air pollution was lower. The predicted results showed that the number of air pollution-related death and DALY would increase. This study comprehensively assessed and predicted the air pollution-related disease burden worldwide. The results indicated that the disease burden would remain very serious in the future. Hence, some relevant policies should be developed to prevent and manage air pollution.

Moving to greener pastures: Health selection into neighborhood green space among a highly mobile and diverse population in California

Global urbanization has sparked substantial environmental, public health, and social science research on the importance of conserving and propagating natural environments. A large subset of this work focuses on the benefits of green space for health. An often-overlooked methodological concern when examining relations between green space and health, however, involves residential self-selection. The selective movement of individuals into greener neighborhoods on the basis of preexisting health and correlated social factors may bias associations, particularly in cross-sectional studies, which predominate existing green space/health research. To quantify the extent of residential self-selection bias, this study used a longitudinal sibling comparison design with repeated individual and neighborhood measures to estimate associations between pre-move health factors, including maternal body mass index (BMI) and infant birthweight, and post-move neighborhood green space in a residentially mobile sample of mothers in California, 2007 to 2015 (n = 288,333). Results show that better health before moving predicted higher levels of neighborhood green space after moving, providing evidence of health selection. Findings also indicate some support for differential health selection into neighborhood green space by race/ethnicity, including that evidence of selection emerges for white and Hispanic, but not Black, mothers. However, weak relations between pre-move individual factors and post-move neighborhood green space across analyses suggest that potential bias due to residential self-selection appears relatively minimal in a large, diverse, and highly mobile sample of families in California. Findings support calls to increase green space in historically marginalized neighborhoods as a means to promote environmental and health equity.

Joint exposure to air pollution, ambient temperature and residential greenness and their association with metabolic syndrome (MetS): A large population-based study among Chinese adults

Previous studies assessing adverse health have traditionally focused on a single environmental exposure, failing to reflect the reality of various exposures present simultaneously. Air pollution, ambient temperature and greenness have been proposed as critical environmental factors associated with metabolic syndrome (MetS). However, evidence exploring their joint relationships with MetS is needed for identifying interactive factors and developing more targeted public health interventions. The baseline data was obtained from China Multi-Ethnic Cohort (CMEC). Environmental data of air pollutants (PM_2.5, O₃) and NDVI for greenness was calculated from satellites data. Ambient temperature data were obtained from European Center for Medium-Range Weather Forecasts (ECMWF). MetS was classified based on National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) using anthropometric measures and biomarkers. Logistic regression models were utilized to examine the combined relationship of MetS with three-year exposure to air pollutants, temperature and NDVI. Relative excess risk due to interaction (RERI) was calculated to evaluate interaction on an additive scale. We found associations between prevalent MetS and interquartile range (IQR) increases in PM_2.5 (OR: 1.38; 95% confidence interval [95% CI]: 1.23, 1.55) and O₃ (OR: 1.15; 95% CI: 1.09, 1.22). Additive and multiplicative interactions were observed between air pollutants and temperature exposure. Compared to low-temperature level, the relationship between PM_2.5 and MetS attenuated (RERI: 0.22, 95% CI: 0.44, -0.04) at high-temperature level, while the relationship between O₃ and MetS enhanced (RERI: 0.05, 95% CI: 0.02, 0.11). At low NDVI 250 m, the association between PM_2.5 and MetS was stronger (RERI: 0.13, 95% CI: 0.05, 0.19) with high NDVI 250 m as the reference group. Our findings showed that ambient temperature and residential greenness could affect the relationship between air pollutants and MetS.

Adverse associations of long-term exposure to ambient ozone with molecular biomarkers of aging alleviated by residential greenness in rural Chinese adults

BACKGROUND

Both ambient ozone exposure and residential greenness are linked to the aging process. However, their interactive effect on molecular biomarkers of aging (telomere length (TL) and mitochondrial DNA copy number (mtDNA-CN)) remains unclear.

METHODS

This study was conducted among 6418 rural Chinese adults. The concentration of ambient ozone was assessed using a random forest model. Residential greenness was represented by the normalized difference vegetation index (NDVI). Molecular biomarkers of aging (relative TL and relative mtDNA-CN) were determined by quantitative real-time polymerase chain reaction. Generalized linear regression models were applied to investigate the independent and combined effects of ambient ozone and residential greenness on relative TL and relative mtDNA-CN.

RESULTS

The estimated percent changes and 95 % confidence intervals (CIs) of relative TL in response to per-unit increase in ambient ozone were -22.43 % (-23.74 %, -21.18 %), -14.19 % (-15.63 %, -12.72 %) and -4.50 % (-6.57 %, -2.27 %) for participants with low (NDVI ≤ 0.53), moderate (0.54-0.55) and high (≥0.56) residential greenness exposure, respectively, while the corresponding figures of relative mtDNA-CN were -12.63 % (-13.84 %, -11.31 %), -9.52 % (-10.60 %, -8.33 %) and 2.12 % (0.20 %, 4.19 %). Furthermore, negative interactive effects between ambient ozone and residential greenness exposure on molecular biomarkers of aging were observed (Pfor interaction < 0.001 for relative TL, and 0.098 for relative mtDNA-CN).

CONCLUSIONS

Long-term exposure to high concentrations of ambient ozone and low residential greenness was associated with decreased mtDNA-CN and shortened TL. The adverse effect of ambient ozone exposure on molecular biomarkers of aging may be attenuated by increased residential greenness.

Early delivery following chronic and acute ambient temperature exposure: a comprehensive survival approach

Background

Ambient temperature, particularly heat, is increasingly acknowledged as a trigger for preterm delivery but study designs have been limited and results mixed. We aimed to comprehensively evaluate the association between ambient temperature throughout pregnancy and preterm delivery.

Methods

We estimated daily temperature throughout pregnancy using a cutting-edge spatiotemporal model for 5347 live singleton births from three prospective cohorts in France, 2002–2018. We performed Cox regression (survival analysis) with distributed lags to evaluate time-varying associations with preterm birth simultaneously controlling for exposure during the first 26 weeks and last 30 days of pregnancy. We examined weekly mean, daytime, night-time and variability of temperature, and heatwaves accounting for adaptation to location and season.

Results

Preterm birth risk was higher following cold (5th vs 50th percentile of mean temperature) 7–9 weeks after conception [relative risk (RR): 1.3, 95% CI: 1.0–1.6 for 2°C vs 11.6°C] and 10–4 days before delivery (RR: 1.6, 95% CI: 1.1–2.1 for 1.2°C vs 12.1°C). Night-time heat (95th vs 50th percentile of minimum temperature; 15.7°C vs 7.4°C) increased risk when exposure occurred within 5 weeks of conception (RR: 2.0, 95% CI: 1.05–3.8) or 20–26 weeks after conception (RR: 2.9, 95% CI: 1.2–6.8). Overall and daytime heat (high mean and maximum temperature) showed consistent effects. We found no clear associations with temperature variability or heatwave indicators, suggesting they may be less relevant for preterm birth.

Conclusions

In a temperate climate, night-time heat and chronic and acute cold exposures were associated with increased risk of preterm birth. These results suggest night-time heat as a relevant indicator. In the context of rising temperatures and more frequent weather hazards, these results should inform public health policies to reduce the growing burden of preterm births.

The type of previous abortion modifies the association between air pollution and the risk of preterm birth

BACKGROUND

Air pollution and previous abortion have been reported to be related to preterm birth (PTB). But rare study examined the effect of air pollution on PTB risk among mothers with previous abortion.

OBJECTIVE

To estimate the effect of air pollution on PTB and the potential effect modification of previous abortion on such an association in rural part of Henan province (China).

METHOD

Based on National Free Preconception Health Examination Project (NFPHEP), information from the medical records of 57,337 mothers with previous abortion were obtained. An inverse distance-weighted model was used to estimate exposure levels of air pollutants. The effect of air pollution on the risk of PTB was estimated with a multiple logistic regression model. Stratified and interaction analyses were undertaken to explore the potential effect modification of previous abortion on this association.

RESULTS

The risk of PTB was positively associated with exposure to levels of nitrogen dioxide (NO₂; OR: 1.03; 95%CI: 1.02-1.04)], and sulfur dioxide (SO₂; 1.04; 1.02-1.07), and negatively associated with ozone (O₃) exposure (0.97; 0.97-0.98) during the entire pregnancy. Besides, we observed a positive effect of carbon monoxide (CO) exposure during the third trimester of pregnancy on PTB (1.14; 1.01-1.29). The type of previous abortion could modify the effect of air pollution on the PTB risk (P-_interaction < 0.05). Compared with mothers with previous induced abortion, mothers with previous spontaneous abortion carried a higher risk of PTB induced by NO₂, CO, and O₃.

CONCLUSIONS

The risk of PTB was positively associated with levels of NO₂, SO₂ and CO, and negatively associated with the O₃ level. The types of previous abortion could modify the effect of air pollution on PTB. Mothers who had an abortion previously, especially spontaneous abortion, should avoid exposure to air pollution to improve their pregnancy outcome.

Assessing the effect of fine particulate matter on adverse birth outcomes in Huai River Basin, Henan, China, 2013-2018

Previous studies have indicated that maternal exposure to particles with aerodynamic diameter <2.5 μm (PM_2.5) is associated with adverse birth outcomes. However, the critical exposure windows remain inconsistent. A retrospective cohort study was conducted in Huai River Basin, Henan, China during 2013-2018. Daily PM_2.5 concentration was collected using Chinese Air Quality Reanalysis datasets. We calculated exposures for each participant based on the residential address during pregnancy. Binary logistic regression was used to examine the trimester-specific association of PM_2.5 exposure with preterm birth (PTB), low birth weight (LBW) and term LBW (tLBW), and we further estimated monthly and weekly association using distributed lag models. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for each 10 μg/m³ increase in PM_2.5 exposure. Stratified analyses were performed by maternal age, infant gender, parity, and socioeconomic status (SES). In total, 196,780 eligible births were identified, including 4257 (2.2%) PTBs, 3483 (1.8%) LBWs and 1770 (0.9%) tLBWs. Maternal PM_2.5 exposure during the second trimester were associated with the risk of PTB and LBW. At the monthly level, the PTB and LBW risks were associated with PM_2.5 exposure mainly in the 4th -6th month. By estimating the weekly-specific association, we observed that critical exposure windows of PM_2.5 exposure and PTB were in the 18th- 27th gestational weeks. Stronger associations were found in younger, multiparous mothers and those with a female baby and in low SES. In conclusion, the results indicate that maternal PM_2.5 exposure during the second trimester was associated with PTB and LBW. Younger, multiparous mothers and those with female babies and in low SES were susceptible.

Effects of extreme temperature on the risk of preterm birth in China: A population-based multi-center cohort study

BACKGROUND

Extreme temperatures are associated with the risk of preterm birth (PTB), but evidence on the effects of different clinical subtypes and across different regions is limited. We aimed to evaluate the effects of maternal exposure to extreme temperature on PTB and its clinical subtypes in China, and to identify effect modification of regional factors in dimensions of population, economy, medical resources and environmental factors.

METHODS

This was a prospective population-based cohort of 210,798 singleton live births from 16 counties in eight provinces across China during 2014-2018. We used an extended Cox regression with time-varying variables to evaluate the effects of extreme heat and cold on PTB and its subtypes in the entire pregnancy, each trimester, the last gestational month and week. Meta-analysis and meta-regression were conducted to estimate the pooled effects of each city and effect modification by regional characteristics.

FINDINGS

Exposure to heat and cold during the entire pregnancy significantly increased the risk of PTB. The effects varied with subtypes, for medically indicated and spontaneous PTB, hazard ratios were 1·84 (95% CI: 1·29, 2·61) and 1·50 (95% CI: 1·11, 2·02) for heat, 2·18 (95% CI: 1·83, 2·60) and 2·15 (95% CI: 1·92, 2·41) for cold. The associations were stronger for PTB less than 35 weeks than those during weeks 35-36. The effects varied across locations, and GDP per capita (β=-0·16) and hospital beds per 1000 persons (β=-0·25) were protective factors for the effects.

INTERPRETATION

Extreme temperature can increase the risk of medically indicated and spontaneous PTB, and higher regional socio-economic status may moderate such effects. In the context of climate change, such findings may have important implications for protecting the health of vulnerable groups, especially newborns.

FUNDING

National Key R&D Program of China (2018YFA0606200), National Natural Science Foundation of China (42175183), Strategic Priority Research Program of the Chinese Academy of Sciences (XDA20030302), National Natural Science Foundation of China (42071377).

Cultural Greenspaces: Synthesizing Knowledge and Experience in Nova Scotia’s African-Canadian Communities through Participatory Research and SoftGIS

Greenspaces are integral components of communities and provide numerous benefits. However, human development threatens these spaces, particularly in communities of color where histories of racial injustice persist and environmental vulnerabilities remain. A step towards preventing the loss of important cultural greenspaces is documenting knowledge and experience. This research employed community-based participatory techniques to study the relationship between the landscape and African-Canadian communities around Preston, Nova Scotia, the oldest and largest in Canada. Community-directed meetings created collaborative-based knowledge about perceptions surrounding land use change while identifying valued greenspaces. This paper studies the relationships between the community’s greenspaces and the benefits to psychological, social, and physical aspects of human wellbeing. This relationship is operationalized through the use of a public participation geographic information system (PPGIS), SoftGIS, which activates the greenspace–human wellbeing relationship through interaction and its map-based survey data collection. Results indicate residents predominately visited greenspaces near a church or community center for social wellbeing benefits to interact with neighbors and friends, to cookout, or to bring children outside. This research contributes to a greater understanding of the Preston area’s greenspace identification and qualification, resident behavior, and cultural perspectives to inform strategies and goals for engaging government agencies surrounding policy and land use planning. This research illustrates frameworks for improving building capacity and promoting racial equity within the urbanization process in other communities.