Traffic-related environmental factors and childhood obesity: A systematic review and meta-analysis

The Association Between a Neighborhood Adverse Childhood Experiences Index and Body Mass Index Among New York City Youth

Background: The role of neighborhood factors in the association between adverse childhood experiences (ACEs) and body mass index (BMI) has not been widely studied. A neighborhood ACEs index (NAI) captures neighborhood environment factors associated with ACE exposure. This study examined associations between BMI and an NAI among New York City (NYC) youth. An exploratory objective examined the NAI geographic distribution across NYC neighborhoods. Methods: Data for students attending NYC public general education schools in kindergarten-12th grade from 2006-2017 (n = 1,753,867) were linked to 25 geospatial datasets capturing neighborhood characteristics for every census tract in NYC. Multivariable hierarchical linear regression tested associations between BMI and the NAI; analyses also were conducted by young (<8 years), school age (8-12 years), and adolescent (>12 years) subgroups. In addition, NAI was mapped by census tract, and local Moran's I identified clusters of high and low NAI neighborhoods. Results: Higher BMI was associated with higher NAI across all sex and age groups, with largest magnitude of associations for girls (medium NAI vs. low NAI: unstandardized β = 0.112 (SE 0.008), standardized β [effect size]=0.097, p < 0.001; high NAI vs. low NAI: unstandardized β = 0.195 (SE 0.008), standardized β = 0.178, p < 0.001) and adolescents (medium NAI vs. low NAI: unstandardized β = 0.189 (SE 0.014), standardized β = 0.161, p < 0.001, high NAI vs. low NAI: unstandardized β = 0.364 (SE 0.015), standardized β = 0.334, p < 0.001 for adolescent girls; medium NAI vs. low NAI: unstandardized β = 0.122 (SE 0.014), standardized β = 0.095, p < 0.001, high NAI vs. low NAI: unstandardized β = 0.217 (SE 0.015), standardized β = 0.187, p < 0.001 for adolescent boys). Each borough of NYC included clusters of neighborhoods with higher and lower NAI exposure, although clusters varied in size and patterns of geographic dispersion across boroughs. Conclusions: A spatial index capturing neighborhood environment factors associated with ACE exposure is associated with higher BMI among NYC youth. Findings complement prior literature about relationships between neighborhood environment and obesity risk, existing research documenting ACE-obesity associations, and the potential for neighborhood factors to be a source of adversity. Collectively, evidence suggests that trauma-informed place-based obesity reduction efforts merit further exploration as potential means to interrupt ACE-obesity associations.

Geospatial analysis for environmental noise mapping: A land use regression approach in a metropolitan city

Environmental noise can lead to adverse health outcomes. Understanding the spatial variability of environmental noise is crucial for mitigating potential health risks and developing influential urban strategies for reducing noise levels. This study aimed to measure noise levels and develop a land use regression (LUR) model to determine the spatial variability of environmental noise in Shiraz, Iran. A grid-based technique was used to establish 191 noise measurement sites (summer) across the city to generate the LUR model based on two noise metrics: Lden and Lnight. Leave-one-out cross-validation (LOOCV) and 38 additional measurement sites (winter) were used for the LUR model assessment. The mean values of Lden and Lnight during summer were 68.20 (±8.05) and 58.95 (±9.55), respectively, while during winter, the corresponding values were 69.46 (±5.46) and 58.81 (±6.79). The LUR models explained 67% and 65% of the spatial variability in Lden and Lnight, respectively. LOOCV analysis demonstrated R2 values of 0.64 and 0.61. Moreover, findings indicated mean absolute error (MAE) values of 3.96 dB(A) for Lden and 4.74 dB(A) for Lnight. Validation based on an additional set of 38 measurement sites revealed R2 values of 0.62 for both Lden and Lnight, with MAE of 2.78 and 3.31, respectively. In addition, the adjusted R2 values were 0.54 and 0.53. The results indicated no significant temporal variations between summer and winter. The results revealed that road-related variables significantly influenced noise levels. Moreover, the results indicated that Lden and Lnight levels were higher than the World Health Organization recommendations for exposure to road traffic noise. The results of our study showed that the LUR modeling approach based on geographical predictors is an effective tool for assessing changes in ambient noise levels in other cities in Iran and around the globe.

Long-term exposure to PM2.5 chemical constituents and diabesity: evidence from a multi-center cohort study in China

Background

Long-term exposure to PM2.5 is known to increase the risks for diabetes and obesity, but its effects on their coexistence, termed diabesity, remain uncertain. This study aimed to investigate the associations of long-term exposure to PM2.5 and its chemical constituents with the risks for diabesity, diabetes, and obesity.

Methods

This cross-sectional study used the baseline data of a multi-center cohort, consisting of three provincially representative cohorts comprising a total of 134,403 participants from the eastern (Fujian Province), central (Hubei Province), and western (Yunnan Province) regions of China. Obesity and diabetes, and diabesity were identified by a body mass index (BMI) ≥28 kg/m2 and fasting plasma glucose (FPG) ≥126 mg/dL. The average concentrations of PM2.5 and five chemical constituents (NO3 -, SO4 2-, NH4 +, organic matter, and black carbon) over participants' residence during the past three years were estimated using machine learning models. Logistic regression models with double robust estimators, Bayesian kernel machine regression, and weighted quantile sum regression were employed to estimate independent and joint effects of PM2.5 chemical constituents on the risks for diabesity, diabetes, and obesity, as well as the differences from the effects on obesity. Stratified analyses were performed to examine effect modification of sociodemographic and lifestyle factors.

Findings

There were 129,244 participants with a mean age of 54.1 ± 13.8 years included in the study. Each interquartile range increase in PM2.5 concentration (8.53 μg/m3) was associated with an increased risk for diabesity (OR = 1.23 [1.17, 1.30]), diabetes only (OR = 1.16 [1.13, 1.19]), and obesity only (OR = 1.03 [1.00, 1.05]). Long-term exposure to each PM2.5 chemical constituent was associated with an increased risk for diabesity, where organic matter exposure, with maximum weight (48%), was associated with a higher risk for diabesity (OR = 1.21 [1.16, 1.27]). Among those with obesity, black carbon contributed most (68%) to the joint effect of PM2.5 chemical constituents on diabesity (OR = 1.16 [1.11, 1.22]). Physical activity reduced adverse effects of PM2.5 on diabesity. Also, additive rather than multiplicative effects of obesity on the PM2.5-diabetes association were observed.

Interpretation

Long-term exposure to PM2.5 and its chemical constituents was associated with an increased risk for diabesity, stronger than associations for diabetes and obesity alone. The main constituents associated with diabesity and obesity were black carbon and organic matter.

Funding

National Natural Science Foundation of China (42271433, 723B2017), National Key R&D Program of China (2023YFC3604702), Fundamental Research Funds for the Central Universities (2042023kfyq04, 2042024kf1024), the Science and Technology Major Project of Tibetan Autonomous Region of China (XZ202201ZD0001G), Science and technology project of Tibet Autonomous Region（XZ202303ZY0007G), Key R&D Project of Sichuan Province (2023YFS0251), Renmin Hospital of Wuhan University (JCRCYG-2022-003), Jiangxi Provincial 03 Special Foundation and 5G Program (20224ABC03A05), Wuhan University Specific Fund for Major School-level Internationalization Initiatives (WHU-GJZDZX-PT07).

The Health-Related and Learning Performance Effects of Air Pollution and Other Urban-Related Environmental Factors on School-Age Children and Adolescents-A Scoping Review of Systematic Reviews

PURPOSE OF REVIEW

This scoping review aims to assess the impact of air pollution, traffic noise, heat, and green and blue space exposures on the physical and cognitive development of school-age children and adolescents. While existing evidence indicates adverse effects of transport-related exposures on their health, a comprehensive scoping review is necessary to consolidate findings on various urban environmental exposures' effects on children's development.

RECENT FINDINGS

There is consistent evidence on how air pollution negatively affects children's cognitive and respiratory health and learning performance, increasing their susceptibility to diseases in their adult life. Scientific evidence on heat and traffic noise, while less researched, indicates that they negatively affect children's health. On the contrary, green space exposure seems to benefit or mitigate these adverse effects, suggesting a potential strategy to promote children's cognitive and physical development in urban settings. This review underscores the substantial impact of urban exposures on the physical and mental development of children and adolescents. It highlights adverse health effects that can extend into adulthood, affecting academic opportunities and well-being beyond health. While acknowledging the necessity for more research on the mechanisms of air pollution effects and associations with heat and noise exposure, the review advocates prioritizing policy changes and urban planning interventions. This includes minimizing air pollution and traffic noise while enhancing urban vegetation, particularly in school environments, to ensure the healthy development of children and promote lifelong health.

Scoping review of obesity interventions: Research frontiers and publication status

Obesity and overweight are significant global health issues, and numerous obesity intervention studies have been conducted. Summarizing current knowledge of interventions aims to inform researchers and policymakers to keep up-to-date with the latest scientific advancements and trends. In this review, we comprehensively retrieved and screened 4,541 studies on obesity intervention published between 2018 and 2022 in the Web of Science Core Collection, and objectively presented research frontiers using bibliometric analysis. The research frontiers of intervention are mainly focused on dietary, exercise, pharmacological interventions, bariatric surgery, environmental, and cognitive interventions. Time-restricted eating is the hottest research topic, followed by probiotics and Roux-en-Y gastric bypass. Gut microbiota is located in the "Basic and transversal themes" quadrant with a high centrality and low density, which has great development potentiality. Obesity intervention is becoming increasingly common,and we advocate for researchers to undertake more focused research endeavors that consider the specific characteristics of diverse populations or patients.

Development of genome-wide association studies on childhood obesity and its indicators: A scoping review and enrichment analysis

BACKGROUND

The progress of genome-wide association studies (GWAS) in childhood obesity and its indicators is challenging and there are differences in genetic studies in children and adults.

OBJECTIVE

To illustrate the history of the development of GWAS in childhood obesity and its indicators and summarize the GWAS loci.

METHODS

PubMed, Web of Science, Embase and GWAS Catalog databases were systematically searched from 1 January 2005 to 19 October 2022 for literature related to GWAS of childhood BMI, body fatness and obesity. The nearest genes were used as positional genes to perform gene set analyses including the enrichment of pathways, tissues and diseases.

RESULTS

Twenty articles published between 2007 and 2021 were included in this scoping review, which identified 116 SNPs reaching genome-wide significance with childhood BMI (n = 50), body fatness (n = 31) and obesity (n = 35). The study populations were European in 16 studies, non-European in three studies (1 East Asian; 1 American; 1 Mexican) and trans-ancestry in one study. Several enriched pathways, tissues and diseases were identified through enrichment analysis of genes associated with childhood obesity and its indicators.

CONCLUSIONS

The innovations in tools and methods enable GWAS to better explore the genetic characteristics of obesity in children and adolescents. However, the number of GWAS in American, Asian and African populations is limited compared to the European population.

A Review of the Role of Built Environment and Temperature in the Development of Childhood Obesity

The burden of obesity is rising globally and is studied widely, yet the evidence for the association of environmental factors (both built and natural) with childhood obesity remains inconsistent. A relation with temperature as a proxy for natural environmental factors for obesity has not been reviewed previously. The purpose of this review was to assimilate updated evidence on environmental factors of childhood obesity. Three databases, MEDLINE (Medical Literature Analysis and Retrieval System Online), Web of Science, and Cochrane, were searched for articles related to the effect of built environment and temperature on childhood obesity in 6-12-year-olds published in the last five years. Twelve studies were identified: four longitudinal and eight cross-sectional. The studies were appraised using the National Institute of Health Quality (NIH) Assessment Tool. A review of included studies showed that built environmental features like higher residential and population density, higher intersection density, more playgrounds, and all park features like the presence or availability of parks, high number of parks, proximity to parks, and an increased park land area, showed a protective association against childhood obesity while land use mix showed a promoting association for the development of childhood obesity. Inconclusive evidence was observed for other built environmental features. The search strategy did not retrieve any literature published in the past five years studying the association between temperature and the development of childhood obesity. Standardization of definitions of exposure and outcome measures is recommended. Further research studying the relationship between environmental temperature and the development of childhood obesity is recommended.

Understanding cross-data dynamics of individual and social/environmental factors through a public health lens: explainable machine learning approaches

Introduction

The rising prevalence of obesity has become a public health concern, requiring efficient and comprehensive prevention strategies.

Methods

This study innovatively investigated the combined influence of individual and social/environmental factors on obesity within the urban landscape of Seoul, by employing advanced machine learning approaches. We collected 'Community Health Surveys' and credit card usage data to represent individual factors. In parallel, we utilized 'Seoul Open Data' to encapsulate social/environmental factors contributing to obesity. A Random Forest model was used to predict obesity based on individual factors. The model was further subjected to Shapley Additive Explanations (SHAP) algorithms to determine each factor's relative importance in obesity prediction. For social/environmental factors, we used the Geographically Weighted Least Absolute Shrinkage and Selection Operator (GWLASSO) to calculate the regression coefficients.

Results

The Random Forest model predicted obesity with an accuracy of >90%. The SHAP revealed diverse influential individual obesity-related factors in each Gu district, although 'self-awareness of obesity', 'weight control experience', and 'high blood pressure experience' were among the top five influential factors across all Gu districts. The GWLASSO indicated variations in regression coefficients between social/environmental factors across different districts.

Conclusion

Our findings provide valuable insights for designing targeted obesity prevention programs that integrate different individual and social/environmental factors within the context of urban design, even within the same city. This study enhances the efficient development and application of explainable machine learning in devising urban health strategies. We recommend that each autonomous district consider these differential influential factors in designing their budget plans to tackle obesity effectively.

Changes in air pollution exposure after residential relocation and body mass index in children and adolescents: A natural experiment study

Air pollution exposure may affect child weight gain, but observational studies provide inconsistent evidence. Residential relocation can be leveraged as a natural experiment by studying changes in health outcomes after a sudden change in exposure within an individual. We aimed to evaluate whether changes in air pollution exposure due to residential relocation are associated with changes in body mass index (BMI) in children and adolescents in a natural experiment study. This population-based study included children and adolescents, between 2 and 17 years, who moved during 2011-2018 and were registered in the primary healthcare in Catalonia, Spain (N = 46,644). Outdoor air pollutants (nitrogen dioxides (NO2), particulate matter <10 μm (PM10) and <2.5 μm (PM2.5)) were estimated at residential census tract level before and after relocation; tertile cut-offs were used to define changes in exposure. Routinely measured weight and height were used to calculate age-sex-specific BMI z-scores. A minimum of 180 days after moving was considered to observe zBMI changes according to changes in exposure using linear fixed effects regression. The majority of participants (60-67% depending on the pollutant) moved to areas with similar levels of air pollution, 15-49% to less polluted, and 14-31% to more polluted areas. Moving to areas with more air pollution was associated with zBMI increases for all air pollutants (β NO2 = 0.10(95%CI 0.09; 0.12), β PM2.5 0.06(0.04; 0.07), β PM10 0.08(0.06; 0.10)). Moving to similar air pollution areas was associated with decreases in zBMI for all pollutants. No associations were found for those moving to less polluted areas. Associations with moving to more polluted areas were stronger in preschool- and primary school-ages. Associations did not differ by area deprivation strata. This large, natural experiment study suggests that increases in outdoor air pollution may be associated with child weight gain, supporting ongoing efforts to lower air pollution levels.

Association of urinary and ambient black carbon, and other ambient air pollutants with risk of prediabetes and metabolic syndrome in children and adolescents

The effects of exposure to black carbon (BC) on various diseases remains unclear, one reason being potential exposure misclassification following modelling of ambient air pollution levels. Urinary BC particles may be a more precise measure to analyze the health effects of BC. We aimed to assess the risk of prediabetes and metabolic syndrome (MetS) in relation to urinary BC particles and ambient BC and to compare their associations in 5453 children from IDEFICS/I. Family cohort. We determined the amount of BC particles in urine using label-free white-light generation under femtosecond pulsed laser illumination. We assessed annual exposure to ambient air pollutants (BC, PM_2.5 and NO₂) at the place of residence using land use regression models for Europe, and we calculated the residential distance to major roads (≤250 m vs. more). We analyzed the cross-sectional relationships between urinary BC and air pollutants (BC, PM_2.5 and NO₂) and distance to roads, and the associations of all these variables to the risk of prediabetes and MetS, using logistic and linear regression models. Though we did not observe associations between urinary and ambient BC in overall analysis, we observed a positive association between urinary and ambient BC levels in boys and in children living ≤250 m to a major road compared to those living >250 m away from a major road. We observed a positive association between log-transformed urinary BC particles and MetS (OR_{per unit increase} = 1.72, 95% CI = 1.21; 2.45). An association between ambient BC and MetS was only observed in children living closer to a major road. Our findings suggest that exposure to BC (ambient and biomarker) may contribute to the risk of MetS in children. By measuring the internal dose, the BC particles in urine may have additionally captured non-residential sources and reduced exposure misclassification. Larger studies, with longitudinal design including measurement of urinary BC at multiple time-points are warranted to confirm our findings.

Environmental noise-induced cardiovascular, metabolic and mental health disorders: a brief review

BACKGROUND

Environmental noise is a pervasive pollutant that is one of the greatest environmental threats to mental, physiological and psychological well-being and has a significant global health burden associated with it. Many epidemiological studies indicate long-term relationship of noise pollution with wide range of metabolic, cardio-vascular and respiratory disorders and diseases.

OBJECTIVE

The goal of this study was to thoroughly analyse available literature on public health implications and various underlying biological mechanisms associated with ambient noise exposure, taking into account both objective and subjective measures of noise exposure.

METHODS

A search of literature for review on environmental noise and associated cardiovascular, mental health and metabolic implications on human health was done using Web of Science, Google Scholar and PubMed databases.

DISCUSSION

Experimental studies indicate that noise exposure leads to endocrine effects, increased incidence of diabetes, impairment of cognitive performance, sleep disturbance and annoyance. Epidemiological evidence indicates that high levels of noise, particularly at night, may cause arterial hypertension and endothelial dysfunction due to higher level of stress hormones and oxidative stress. An increased incidence of cardio-vascular diseases like myocardial infarction, heart rate, ischemic heart disease, stroke and heart failure is associated with noise-induced mental stress. Furthermore, psychological and mental health issues like anxiety and depression are also related with exposure to noise pollution.

CONCLUSION

This article summarises a comprehensive and systematic knowledge established in recent noise research with the spotlight on cardiovascular, metabolic and mental health disorders of environmental noise, providing unique understanding into underlying mechanisms.

Ethnic disparities in the association between ambient air pollution and risk for cardiometabolic abnormalities in China

BACKGROUND

Long-term exposure to ambient air pollution has been associated with cardiometabolic abnormalities (CAs), which, however, may be stronger in vulnerable populations, such as minorities. The variation of the association between ambient air pollution and CAs between the majority (Han) and minority populations in China have been poorly studied.

OBJECTIVES

We aimed to estimate and compare the Hans' and minorities' risks for CAs associated with long-term exposure to ambient air pollution in Southwest China.

METHODS

A cross-sectional study was conducted on the basis of the China Multi-Ethnic Cohort. CAs were defined by the presence of at least three pre-defined metabolic dysfunctions (central obesity, elevated triglycerides, reduced high-density lipoprotein cholesterol, elevated blood pressure, and elevated fasting glucose). The concentrations of ambient air pollutants, including particulate matters (PM₁, PM_2.5, and PM₁₀) and nitrogen dioxide (NO₂), were generated from random forest models on the basis of multi-source data. One- and two-pollutant regression models were fit to assess associations between air pollutant exposure and CA risks. Sensitivity analyses were performed to examine the robustness of the associations.

RESULTS

The final sample included 51,037 Hans and 28,702 minority participants. The prevalence of CAs was 25.0%, slightly higher in the minorities (25.5%) than the Hans (24.4%). The higher risks for CAs in the overall population were associated with each 10 μg/m³ increase in the exposure to PM₁ (OR = 1.07 [1.05-1.09]), PM_2.5 (OR = 1.11 [1.06-1.17]), PM₁₀ (OR = 1.04 [1.03-1.06]), and NO₂ (OR = 1.04 [1.03-1.07]). Compared to the Hans, the higher risks for CAs were observed in the minorities for PM₁ (OR = 1.35 [1.18-1.53]), PM_2.5 (OR = 1.61 [1.34-1.93]), and PM₁₀ (OR = 1.15 [1.07-1.23]). The associations of metabolic dysfunctions (CA components) with ambient air pollution also varied between the Han and minority populations.

CONCLUSIONS

The associations between exposure to ambient air pollution and CA risks were stronger in the minorities than Hans. Our findings provide a better understanding of ethnic disparities in CA risks when being exposed to ambient air pollution in China, which also have important implications for other low- and middle-income countries where less health resources (e.g., cohort populations) are available to conduct such studies.

Changes in neighborhood environments and the increasing socioeconomic gap in child obesity risks: Evidence from Singapore

Most empirical research studying the link between neighborhood environments and child obesity risks are conducted in contexts such as the U.S., with pronounced patterns of residential segregation, making it difficult to extrapolate how far built environment characteristics contribute to socioeconomic disparities in obesity risks in less segregated contexts. Using a large national dataset of almost 625,000 students' height and weight data collected at ages 7, 11 and 14, between 2004 and 2015, this paper explores whether differences in eight neighborhood characteristics measuring access to different type of food outlets, parks and other active spaces, and public transport infrastructure might be responsible for socioeconomic differences in child obesity risks in Singapore, a city-state with relatively low levels of residential segregation. Through descriptive analyses we find that socioeconomic disparities in child BMIz in Singapore widened from 2004 onwards. However, while longitudinal regression models with individual and time fixed effects suggest that family socioeconomic status modified the relationship between environmental exposures and BMIz, there does not seem to be a clear, unequivocal relationship between built environment changes and the observed widening of the socioeconomic obesity gap.

The Association between Childhood Exposure to Ambient Air Pollution and Obesity: A Systematic Review and Meta-Analysis

Obesity has become a worldwide epidemic; 340 million of children and adolescents were overweight or obese in 2016, and this number continues to grow at a rapid rate. Epidemiological research has suggested that air pollution affects childhood obesity and weight status, but the current evidence remains inconsistent. Therefore, the aim of this meta-analysis was to estimate the effects of childhood exposure to air pollutants on weight. A total of four databases (PubMed, Web of Science, Embase, and Cochrane Library) were searched for publications up to December 31, 2021, and finally 15 studies met the inclusion criteria for meta-analysis. Merged odds ratios (ORs), coefficients (β), and 95% confidence intervals (95% CIs) that were related to air pollutants were estimated using a random-effects model. The meta-analysis indicated that air pollutants were correlated with childhood obesity and weight gain. For obesity, the association was considerable for PM₁₀ (OR = 1.12, 95% CI: 1.06, 1.18), PM_2.5 (OR = 1.28, 95% CI: 1.13, 1.45), PM₁ (OR = 1.41, 95% CI: 1.30, 1.53), and NO₂ (OR = 1.11, 95% CI: 1.06, 1.18). Similarly, BMI status increased by 0.08 (0.03-0.12), 0.11 (0.05-0.17), and 0.03 (0.01-0.04) kg/m² with 10 μg/m³ increment in exposure to PM₁₀, PM_2.5, and NO₂. In summary, air pollution can be regarded as a probable risk factor for the weight status of children and adolescents. The next step is to conduct longer-term and large-scale studies on different population subgroups, exposure concentrations, and pollutant combinations to provide detailed evidence. Meanwhile, integrated management of air pollution is essential.

Prenatal exposure to ambient air pollution and traffic and indicators of adiposity in early childhood: the Healthy Start study

BACKGROUND

Prenatal exposure to ambient air pollution and traffic have been related to a lower birth weight and may be associated with greater adiposity in childhood. We aimed to examine associations of maternal exposure to ambient air pollution and traffic during pregnancy with indicators of adiposity in early childhood.

METHODS

We included 738 participants of the Colorado-based Healthy Start study whose height, weight, waist circumference and/or fat mass were measured at age 4-6 years. We estimated residential exposure to ambient concentrations of fine particulate matter (PM_2.5) and ozone (O₃) averaged by trimester and throughout pregnancy via inverse distance-weighted interpolation of central site monitoring data. We assessed the distance to the nearest major roadway and traffic density in multiple buffers surrounding the participants' homes. Associations of prenatal exposure to air pollution and traffic with overweight, waist circumference, percent fat mass and fat mass index (FMI) were assessed by logistic and linear regression.

RESULTS

Associations of exposure to PM_2.5 and O₃ at the residential address during pregnancy with percent fat mass and FMI at age 4-6 years were inconsistent across trimesters. For example, second trimester PM_2.5 was associated with a higher percent fat mass (adjusted difference 0.70% [95% CI 0.05, 1.35%] per interquartile range (IQR; 1.3 µg/m³) increase), while third trimester PM_2.5 was associated with a lower percent fat mass (adjusted difference -1.17% [95% CI -1.84, -0.50%] per IQR (1.3 µg/m³) increase). Residential proximity to a highway during pregnancy was associated with higher odds of being overweight at age 4-6 years. We observed no associations of prenatal exposure to PM_2.5 and O₃ with overweight and waist circumference.

CONCLUSIONS

We found limited evidence of associations of prenatal exposure to ambient PM_2.5 and O₃ with indicators of adiposity at age 4-6 years. Suggestive relationships between residential proximity to a highway during pregnancy and greater adiposity merit further investigation.

Influences and transmission mechanisms of financial agglomeration on environmental pollution

The mechanism between financial agglomeration and environmental pollution is an important concern for both academia and policymaking. The main objective of this paper is to study the nonlinear impacts of financial agglomeration on environmental pollution. A theoretical framework was first constructed based on the scale effect, structure effect, and technology innovation effect of financial agglomeration and a Copeland-Taylor endogenous growth model. Using the panel data of 281 Chinese prefectural-level cities from 2003 to 2019, a panel threshold regression model was introduced to estimate the nonlinear association between financial agglomeration and environmental pollution. Industrial smoke (dust) emissions and industrial wastewater discharge were adopted to quantify current environmental pollution in China. The results show that financial agglomeration had a significant effect on improving the environment characterized by gradient thresholds; also notable is that 68.64% of the cities crossed the threshold value, entering the decelerating phase of financial agglomeration inhibiting environmental pollution. Both upgrading industrial structure and enhancing marketization could reduce environmental pollution, whereas increasing human capital, environmental regulation, and energy consumption had a deteriorating effect. The three channels for financial agglomeration to reduce environmental pollution were revealed to be financial scale, financial structure, and financial technology innovation. Our findings provide strong evidence for policymaking in sustainable development.

Associations of self-reported residential noise exposure with obesity and hypertension in children and adolescents

BACKGROUND

Epidemiologic evidence linking environmental noise to obesity and hypertension remains scarce, especially in children, and the results remain inconclusive. This study aims to examine the cross-sectional associations of self-reported residential noise exposure with obesity and hypertension in children and adolescents.

METHODS

As an ongoing study, a representative sample of the children aged 6-9 years in Chongqing were selected in 2014. In 2019, self-reported residential noise (answer categories: "very quiet," "moderately quiet," "slightly quiet," and "not at all quiet") data were collected, and 3,412 participants with completed data were included in the analyses.

RESULTS

Participants living in a quieter area had a significantly lower risk of obesity than those living in a noisy area (very quiet: OR = 0.50, 95%CI: 0.29-0.88, P = 0.015; moderately quiet: OR = 0.61, 95%CI: 0.36-1.02, P = 0.059). Similar associations were observed for abdominal obesity, although did not reach statistical significance. Consistently, residential noise exposure was significantly associated with body mass index (BMI) and waist-to-height ratio. Self-reported residential noise exposure was positively associated with systolic blood pressure (β = -1.808; 95%CI = -3.495, -0.110; P = 0.037). When sleep quality, study stress, BMI, and vegetable/fruits consumption were further adjusted, all effect estimates decreased, and no statistical association was observed between noise exposure and blood pressure. Furthermore, we found that the mediating effects of obesity on the associations of self-reported residential noise exposure with hypertension were 6.8% (% of total effect mediated = 0.068, 95%CI: -2.58, 3.99), although did not reach statistical significance.

CONCLUSIONS

Self-reported residential noise exposure was associated with a higher risk of obesity or abdominal obesity. Also, self-reported residential noise exposure was positively associated with hypertension, and obesity may partially mediate this association, but did not reach statistical significance.

Neighborhood built environment typologies and adiposity in children and adolescents

BACKGROUND/OBJECTIVES

Neighborhoods are complex, multidimensional systems. However, the interrelation between multiple neighborhood dimensions is seldom considered in relation to youth adiposity. We created a neighborhood typology using a range of built environment features and examined its association with adiposity in youth.

SUBJECTS/METHODS

Analyses are based on data from the QUALITY cohort, an ongoing study on the natural history of obesity in Quebec youth with a history of parental obesity. Adiposity was measured at baseline (8-10 years) and follow up, ~8 years later. Neighborhood features were measured at baseline through in-person neighborhood assessments and geocoded administrative data and were summarized using principal components analysis. Neighborhood types were identified using cluster analysis. Associations between neighborhood types and adiposity were examined using multivariable linear regressions.

RESULTS

Five distinct neighborhood types characterized by levels of walkability and traffic-related safety were identified. At ages 8-10 years, children in moderate walkability/low safety neighborhoods had higher BMI Z-scores [β: 0.41 (0.12; 0.71), p = 0.007], fat mass index [β: 1.22 (0.29; 2.16), p = 0.010], waist circumference [β: 4.92 (1.63; 8.21), p = 0.003], and central fat mass percentage [β: 1.60 (0.04; 3.16), p = 0.045] than those residing in moderate walkability/high safety neighborhoods. Attenuated associations were observed between neighborhood types and adiposity 8 years later. Specifically, residents of moderate walkability/low safety neighborhoods had a higher FMI [β: 1.42 (-0.07; 2.90), p = 0.062], and waist circumference [β: 5.04 (-0.26; 10.34), p = 0.062].

CONCLUSIONS

Neighborhoods characterized by lower traffic safety appear to be the most obesogenic to children, regardless of other walkability-related features. Policies targeting neighborhood walkability for children may need to prioritize vehicular traffic safety.

Association between air pollution, body mass index, respiratory symptoms, and asthma among adolescent school children living in Delhi, India

Background:

Delhi is one of the most polluted cities in the world with annual average ambient PM₁₀ and PM_2.5 levels exceeding the World Health Organization standards by over 15 fold. We aimed to study the prevalence of respiratory and allergic symptoms and asthma among adolescent children living in Delhi (D) and compare it with children living in lesser polluted cities of Kottayam (K) and Mysore (M) located in Southern India.

Methods:

4361 boys and girls between the age group of 13–14 and 16–17 years from 12 randomly selected private schools from D, K, and M were invited to participate. Modified and expanded International Study for Asthma and Allergies in Children (ISAAC) questionnaires (Q) were filled by the students who also performed spirometry using the ultrasonic flow-sensor-based nDD Spirometer.

Results:

3157 students (50.4% boys) completed the Q and performed good quality spirometry. The prevalence of asthma and airflow obstruction among children living in Delhi was 21.7% using the ISAAC Q and 29.4% on spirometry, respectively. This was accompanied by significantly higher rates of self-reported cough, shortness of breath, chest tightness, sneezing, itchy and watery eyes, itchy skin, and eczema among Delhi children (vs. K-M, all P < 0.05). Delhi children were more overweight and obese (39.8% vs. 16.4%, P < 0.0001), and this was the only risk factor that was strongly associated with asthma (odds ratio [OR]: 1.79; confidence interval: 1.49–2.14), with a more pronounced effect in Delhi children (P = 0.04). Forced expiratory volume₁ and Forced vital capacity values were significantly higher in Delhi children (vs. K-M P < 0.0001). Preserved ratio impaired spirometry was more common in K-M children (P < 0.0001).

Conclusion:

Adolescent children living in the polluted city of Delhi had a high prevalence of asthma, respiratory symptoms, allergic rhinitis, and eczema that was strongly associated with a high body mass index (BMI). Our study suggests an association between air pollution, high BMI, and asthma/allergic diseases, which needs to be explored further.

Ambient air pollution and the development of overweight and obesity in children: a large longitudinal study

BACKGROUND

Ambient air pollution may play a role in childhood obesity development, but evidence is scarce, and the modifying role of socioeconomic status (SES) is unclear. We aimed to examine the association between exposure to air pollution during early childhood and subsequent risk of developing overweight and obesity, and to evaluate whether SES is a modifier of this association.

METHODS

This longitudinal study included 416,955 children identified as normal weight between 2-5 years old and registered in an electronic primary healthcare record between 2006 and 2016 in Catalonia (Spain). Children were followed-up until they developed overweight or obesity, reached 15 years of age, died, transferred out, or end of study period (31/12/2018). Overweight and obesity were defined following the WHO reference obtained from height and weight measures. We estimated annual residential census levels of nitrogen dioxide (NO₂) and particulate matter <10 μm (PM₁₀), <2.5 μm (PM_2.5), and 2.5-10 μm (PM_coarse) at study entry. We estimated the risk of developing overweight and obesity per interquartile range increase in air pollution exposure with Cox proportional hazard models.

RESULTS

A total of 142,590 (34.2%) children developed overweight or obesity. Increased exposure to NO₂, PM₁₀, and PM_coarse was associated with a 2-3% increased risk of developing overweight and obesity (hazard ratio [HR] per 21.8 μg/m³ NO₂ = 1.03 [95% CI: 1.02-1.04]; HR per 6.4 μg/m³ PM₁₀ = 1.02 [95% CI: 1.02-1.03]; HR per 4.6 µg/m³ PM_coarse = 1.02, [95% CI: 1.01-1.02]). For all air pollutants, associations were stronger among children living in most compared to least deprived areas.

CONCLUSIONS

This study suggests that early life exposure to air pollution may be associated with a small increase in the risk of developing overweight and obesity in childhood, and that this association may be exacerbated in the most deprived areas. Even these small associations are of potential global health importance because air pollution exposure is widespread and the long-term health consequences of childhood obesity are clear.

Urban sprawl and childhood obesity

Urban sprawl is thought to be a risk factor for childhood obesity primarily because the physical environment it creates discourages children's physical activity while encouraging their sedentary behavior. However, there has not been any review on the association between urban sprawl and childhood obesity. This study filled this research gap by comprehensively reviewing literature focusing on associations between urban sprawl and weight-related behaviors and outcomes among children and adolescents. Only two longitudinal and three cross-sectional studies conducted in two countries were identified. Sample sizes ranged from 2324 to 129 781. Four studies used weight status, and only one study used both behaviors and weight status as outcome variables. All positive, negative, and non-significant associations were reported. This review could not identify a clear association between urban sprawl and childhood obesity. More longitudinal studies are needed for in-depth analyses on this important topic in more regions, which would be important not only for public health guidelines but also for research, practice, and policies in urban planning.

Neighbourhood speed limit and childhood obesity

As an important factor for neighbourhood walkability, the speed limit in the neighbourhood may influence children's physical activity (PA) outdoors, especially active transport, and further their weight status. This review aimed to systematically evaluate the association between neighbourhood speed limit and obesity-related behaviours and outcomes among children and adolescents. PubMed, Embase and Web of Science were systematically searched for relevant studies published from the inception of the database to 1 January 2019. Sixteen studies were included, with 13 cross-sectional studies and three longitudinal studies. Speed limit was measured as the percentage/number of high-speed roads, perception of safe driving speed, perception of speeding and use of traffic-calming tools in the neighbourhood. Eleven studies measured the use of active transport as the outcome of interest, and seven studies measured PA directly. Eleven studies revealed an association between a lower speed limit and increased PA, whereas one study showed a negative association, and three studies reported non-significant associations. Only one study associated speed limit with weight status, which reported a non-significant association. This review generally supported a negative association between speed limit and PA among children and adolescents. More studies are needed to examine their causality, as well as the association between speed limit and weight status, in order to increase the impact of this research area on public health policy making.

Traffic-related environmental factors and childhood obesity: A systematic review and meta-analysis

A growing body of research links traffic-related environmental factors to childhood obesity; however, the evidence is still inconclusive. This review aims to fill this important research gap by systematically reviewing existing research on the relationship between traffic-related environmental factors and childhood obesity. Based on the inclusion criteria, 39 studies are selected with environmental factors of interest, including traffic flow, traffic pollution, traffic noise, and traffic safety. Weight-related behaviours include active travel/transport, physical activity (PA), and intake of a high trans-fat diet or stress symptoms; weight-related outcomes are mainly body mass index (BMI) or BMI z-scores and overweight/obesity. Of 16 studies of weight-related behaviours, significant associations are reported in 11 out of 12 studies on traffic flow (two positively and nine negatively associated with PA), five out of six studies on traffic safety (four positively and one negatively associated with PA), one study on traffic pollution (positively with unhealthy food consumption), and one study on traffic noise (negatively associated with PA). Among 23 studies of weight-related outcomes, significant associations are reported in six out of 14 studies on traffic flow (five positively and one negatively associated with obesity outcome), seven out of 10 studies on traffic pollution (all positively associated with obesity outcome), and two out of five on traffic noise (all positively associated with obesity outcome). Our findings show that long-term traffic pollution is weakly positively associated with children's BMI growth, and traffic flow, pollution, and noise could affect weight-related behaviours. Associations between traffic density and noise and weight status are rather inconclusive.

Natural environment and childhood obesity: A systematic review

The associations between built and food environments and childhood obesity have been studied extensively. However, the association between the natural environment and childhood obesity has received too little scholarly attention. This study reviewed the literature published before 1 January 2019, which described associations between a full range of natural environmental factors (e.g., rainfall, temperature, sunlight, natural disasters, flood and drought) and weight-related behaviours and childhood obesity. Five cross-sectional studies and one longitudinal study were identified. Measures of natural environmental factors varied across six included studies, falling into five broad categories: weather conditions, altitude, natural disaster risk, air quality and day length. It was found that temperature was a significant weather indicator in most included studies and was associated with a reduction of daily physical activity. Children living in high-altitude areas were more likely to be shorter and heavier than their counterparts in low-altitude areas. Findings of this study will contribute to helping multiple stakeholders, including policy makers and urban planners, and formulate health policies and interventions to mitigate the detrimental impact of the natural environment on childhood obesity. More longitudinal studies should be designed to confirm these effects and explore the potential health effects of more natural environmental factors.

The association between road traffic noise and myocardial infarction: A systematic review and meta-analysis

This systematic review and meta-analysis study aimed to investigate the association between exposure to road traffic noise (RTN) and myocardial infarction (MI). Of 681 studies found by searching in databases, including Scopus, Web of Science, Embase, and PubMed on November 29, 2019, the number of 13 studies, including seven cohort, five case-control, and one cross-sectional studies with 1,626,910 participants and 45,713 cases of MI was included. The pooled relative risk (RR) and 95% confidence interval (CI) of MI were calculated using a random-effect model across studies. Heterogeneity measures by reporting the I-square index. Subgroup analysis according to the designs and sensitivity analysis based on the Jackknife approach was performed. We observed in the eight studies the association was investigated in different noise exposure groups and in the 10 studies (including two conference papers) the risk of MI was provided per specific unit increment of RTN. We ran two independent types of meta-analyses involving a categorical analysis (comparing the highest and the lowest category of noise exposure groups) and an exposure-response analysis (the risk of MI per 10-dB increment of RTN). The pooled RR (95% CI) of MI for the categorical and exposure-response meta-analyses was calculated 1.03 (0.93, 1.13) and 1.02 (1.00, 1.05), respectively. For both types of meta-analyses, subgroup analysis indicates a significant association in the studies with case-control and cross-sectional designs but not cohort studies. For the exposure-response meta-analysis, a significantly greater risk of MI was observed after excluding the two conference papers (RR = 1.03 and 95% CI = 1.00, 1.05) and by further excluding the studies provided originally the risk of MI only for the categorical analysis (RR = 1.02 and 95% CI = 1.01, 1.03). We did not show a significant publication bias across studies. In conclusion, our study suggests a significant odds of association between exposure to RTN and the risk of MI.