The final 28 Days:Prenatal exposure to air pollution and child anthropometric outcomes

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.

Interventions to reduce the effects of air pollution and of extreme heat on maternal, newborn, and child health outcomes: a mapping of the literature

Background

There is an increasing awareness of the ongoing and projected impacts of air pollution and of extreme heat on maternal, newborn, and child health (MNCH) outcomes, showing significant short and long-term health problems. There is a dearth of information available for policy makers on interventions that have been implemented to reduce the impact on MNCH, impeding the integration of action into health planning. This paper presents an inventory of interventions aimed at reducing the effects of these two climate hazards on MNCH.

Methods

We conducted a scoping review of articles published in three databases and grey literature to identify and map interventions implemented to address the impact of air pollution and/or extreme heat on MNCH. Items were included if published between January 2016 and November 2022, regardless of language, and as this is an inventory, regardless of if the intervention was evaluated. Over 32 700 journal items were reviewed for inclusion and a sample of grey literature from web-based searches.

Results

A final inventory of 76 items were included. Interventions identified were primarily based in the Global North (n = 51), with the largest proportion in the USA (n = 17), while 32 items were based in the Global South. Fifty-seven items focused on air pollution, 18 on extreme heat, and one on both. Interventions were categorised in four adapted socioecological components: (i) individual and household interventions (n = 30), (ii) community and service interventions (n = 18), (iii) structural interventions and urban landscape interventions (n = 15), (iv) policy interventions (n = 16). Most items were focused on child health outcomes (n = 65); 61 items were evaluated.

Conclusions

This scoping review maps interventions implemented and proposes a categorisation of these to initiate reflections and dialogue on what has been done and how to start building an evidence base. The review also highlights gaps in interventions and the knowledge base, with most interventions implemented to address air pollution, in the Global North and most addressing child health need. As country programmes seek to address the impact of climate change on MNCH, additional efforts are needed to better understand what has been done, document lessons learned, agree on common outcome measurements and feasible study designs for evaluation to start building the evidence base.

Household energy transition and its crucial role in saving infant lives in developing countries

This study estimates the impact of reducing household solid fuel dependence on the infant mortality rate (IMR) in developing countries, where traditional solid fuels such as firewood and coal are widely used. Utilizing panel data from 76 developing countries over the period 1990 to 2020, our findings indicate that IMR drops substantially as household reliance on solid fuels decreases. A 1% reduction in per capita solid fuel consumption is linked to an average 0.11% reduction in IMR. Furthermore, for each percentage point decrease in the proportion of households using solid cooking fuels, the IMR declines by an average of 0.5%. Notably, the detrimental impacts of solid fuel use on IMR diminish as income and urbanization levels rise. Our analysis shows that between 1990 and 2020, the reductions in the proportion of households relying on solid fuels contributed to approximately 23.2% of the decline in IMR in developing countries, potentially preventing an estimated 937,260 infant deaths.

Associations between maternal exposure to air pollution during pregnancy and trajectories of infant growth: A birth cohort study

OBJECTIVE

We examined the relationships between infants' growth trajectories and prenatal exposure to air pollution, which is still under-investigated.

METHODS

A birth cohort study was constructed using medical records of pregnant women and infants born between 2015 and 2019 in Foshan, China. Using satellite-based spatial-temporal models, prenatal exposure to air pollutants including particulate matter with an aerodynamic dimension of < 2.5 µm (PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3) was assessed at each woman's residence. Latent class growth modeling was used to identify trajectories of physical (body length and weight) growth and neurodevelopment, which were repeatedly measured within 1 year after birth. Logistic regression models were used to investigate the associations between prenatal exposure to air pollution and the risks of growth disorders, adjusting for an array of potential confounders.

RESULTS

We identified two growth trajectories for body length [normal: 3829 (93%); retardation: 288 (7%)], three for weight [normal: 2475 (59.6%); retardation: 390 (9.4%); overgrowth: 1287 (31%)], and two for neurodevelopment [normal: 956 (66.1%); retardation: 491 (33.9%)]. For exposure over whole pregnancy, SO2 was associated with an increased risk of body length retardation (OR for per 1 µg/m3 increment: 1.09, 95%CI: 1.01-1.17); PM2.5 (OR: 1.05, 95%CI: 1.03-1.07), SO2 (OR: 1.15, 95%CI: 1.08-1.22), and NO2 (OR: 1.05, 95%CI: 1.03-1.07) were positively associated with neurodevelopmental retardation. Such associations appeared stronger for exposures over the first and second trimesters. No significant associations were detected for weight growth.

CONCLUSIONS

Maternal exposure to air pollution during pregnancy was associated with higher risks of impairments in both physical growth, particularly body length, and neurodevelopment.

Industrial air pollution and low birth weight in New Mexico, USA

In recent decades, the low birth weight (LBW) rate in New Mexico has consistently exceeded the Unites States average. Maternal exposure to air pollution during pregnancy may be a significant contributor to LBW in offspring. This study investigated the links between maternal residential exposure to air pollution from industrial sources and the risk of LBW in offspring. The analysis included 22,375 LBW cases and 233,340 controls. It focused on 14 common chemicals listed in the Toxic Release Inventory (TRI) and monitoring datasets, which have abundant monitoring samples. The Emission Weighted Proximity Model (EWPM) was used to calculate maternal air pollution exposure intensity. Adjusted odds ratios (adjORs) were calculated using binary logistic regressions to examine the association between maternal residential air pollution exposure and LBW, while controlling for potential confounders, such as the maternal age, race/ethnicity, gestational age, prenatal care, education level, consumption of alcohol during pregnancy, public health regions, child's sex, and the year of birth. Multiple comparison correction was applied using the False Discovery Rate approach. The results showed that maternal residential exposure to 1,2,4-trimethylbenzene, benzene, chlorine, ethylbenzene, and styrene had significant positive associations with LBW in offspring, with adjusted odds ratios ranging from 1.10 to 1.13. These five chemicals remained as significant risk factors after dividing the estimated exposure intensities into four categories. In addition, significant linear trends were found between LBW and maternal exposure to each of the five identified chemicals. Furthermore, 1,2,4-trimethylbenzene was identified as a risk factor to LBW for the first time. The findings of this study should be confirmed through additional epidemiological, biological, and toxicological studies.