Effects of air pollution exposure on glucose metabolism in Los Angeles minority children

The association between air pollution and obesity: an umbrella review of meta-analyses and systematic reviews

The objective of this umbrella review was to investigate comprehensive and synthesized evidence of the association between ambient air pollution and obesity based on the current systematic reviews and meta-analyses. Related studies from databases including PubMed, EMBASE, Web of Science, and the Cochrane Library, published before July 16, 2023, were considered in the analysis. All selected systematic reviews and meta-analyses were included in accordance with PRISMA guidelines. The risk of bias and the methodological quality were evaluated using the AMSTAR 2 tool. The protocol for this umbrella review was documented in PROSPERO with the registration number: CRD42023450191. This umbrella review identified 7 studies, including 5 meta-analyses and 2 systematic reviews, to assess the impacts of air pollutants on obesity. Commonly examined air pollutants included PM1, PM2.5, PM10, NO2, SO2, O3. Most of the included studies presented that air pollution exposure was positively associated with the increased risk of obesity. The impact of air pollution on obesity varied by different ambient air pollutants. This study provided compelling evidence that exposure to air pollution had a positive association with the risk of obesity. These findings further indicate the importance of strengthening air pollution prevention and control. Future studies should elucidate the possible mechanisms and pathways linking air pollution to obesity.

Determinants of obesity in Latin America

Obesity rates are increasing almost everywhere in the world, although the pace and timing for this increase differ when populations from developed and developing countries are compared. The sharp and more recent increase in obesity rates in many Latin American countries is an example of that and results from regional characteristics that emerge from interactions between multiple factors. Aware of the complexity of enumerating these factors, we highlight eight main determinants (the physical environment, food exposure, economic and political interest, social inequity, limited access to scientific knowledge, culture, contextual behaviour and genetics) and discuss how they impact obesity rates in Latin American countries. We propose that initiatives aimed at understanding obesity and hampering obesity growth in Latin America should involve multidisciplinary, global approaches that consider these determinants to build more effective public policy and strategies, accounting for regional differences and disease complexity at the individual and systemic levels.

Effects of ambient air pollution on obesity and ectopic fat deposition: a protocol for a systematic review and meta-analysis

INTRODUCTION

Globally, the prevalence of obesity tripled from 1975 to 2016. There is evidence that air pollution may contribute to the obesity epidemic through an increase in oxidative stress and inflammation of adipose tissue. However, the impact of air pollution on body weight at a population level remains inconclusive. This systematic review and meta-analysis will estimate the association of ambient air pollution with obesity, distribution of ectopic adipose tissue, and the incidence and prevalence of non-alcoholic fatty liver disease among adults.

METHODS AND ANALYSIS

The study will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for conduct and reporting. The search will include the following databases: Ovid Medline, Embase, PubMed, Web of Science and Latin America and the Caribbean Literature on Health Sciences, and will be supplemented by a grey literature search. Each article will be independently screened by two reviewers, and relevant data will be extracted independently and in duplicate. Study-specific estimates of associations and their 95% Confidence Intervals will be pooled using a DerSimonian and Laird random-effects model, implemented using the RevMan software. The I2 statistic will be used to assess interstudy heterogeneity. The confidence in the body of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

ETHICS AND DISSEMINATION

As per institutional policy, ethical approval is not required for secondary data analysis. In addition to being published in a peer-reviewed journal and presented at conferences, the results of the meta-analysis will be shared with key stakeholders, health policymakers and healthcare professionals.

PROSPERO REGISTRATION NUMBER

CRD42023423955.

Early-life exposure to residential black carbon and childhood cardiometabolic health

BACKGROUND

Early life exposure to air pollution, such as particulate matter ≤2.5 μm (PM2.5), may be associated with obesity and adverse cardiometabolic health outcomes in childhood. However, the toxicity of PM2.5 varies according to its chemical composition. Black carbon (BC) is a constituent of PM2.5, but few studies have examined its impact on childhood cardiometabolic health. Therefore, we examined relationships between prenatal and early childhood exposure to BC and markers of adiposity and cardiometabolic health in early childhood.

METHODS

This study included 578 mother-child pairs enrolled in the Healthy Start study (2009-2014) living in the Denver-metro area. Using a spatiotemporal prediction model, we assessed average residential black carbon levels during pregnancy and in the year prior to the early childhood follow-up visit at approximately 5 years old. We estimated associations between prenatal and early childhood BC and indicators of adiposity and cardiometabolic biomarkers in early childhood (mean 4.8 years; range, 4.0, 8.3), using linear regression.

RESULTS

We found higher early childhood BC was associated with higher percent fat mass, fat mass index, insulin, and homeostatic model assessment for insulin resistance (HOMA-IR), and lower leptin and waist circumference at approximately 5 years old, after adjusting for covariates. For example, per interquartile range (IQR) increase in early childhood BC (IQR, 0.49 μg/m3) there was 3.32% higher fat mass (95% CI; 2.05, 4.49). Generally, we did not find consistent evidence of associations between prenatal BC and cardiometabolic health outcomes in early childhood, except for an inverse association between prenatal BC and adiponectin, an adipocyte-secreted hormone typically inversely associated with adiposity.

CONCLUSIONS

Higher early childhood, but not in utero, ambient concentrations of black carbon, a component of air pollution, were associated with greater adiposity and altered insulin homeostasis at approximately 5 years old. Future studies should examine whether these changes persist later in life.

Redox and inflammatory mechanisms linking air pollution particulate matter with cardiometabolic derangements

Air pollution is the largest environmental risk factor for disease and premature death. Among the different components that are present in polluted air, fine particulate matter below 2.5 μm in diameter (PM2.5) has been identified as the main hazardous constituent. PM2.5 mainly arises from fossil fuel combustion during power generation, industrial processes, and transportation. Exposure to PM2.5 correlates with enhanced mortality risk from cardiovascular diseases (CVD), such as myocardial infarction and stroke. Over the last decade, it has been increasingly suggested that PM2.5 affects CVD already at the stage of risk factor development. Among the multiple biological mechanisms that have been described, the interplay between oxidative stress and inflammation has been consistently highlighted as one of the main drivers of pulmonary, systemic, and cardiovascular effects of PM2.5 exposure. In this context, PM2.5 uptake by tissue-resident immune cells in the lung promotes oxidative and inflammatory mediators release that alter tissue homeostasis at remote locations. This pathway is central for PM2.5 pathogenesis and might account for the accelerated development of risk factors for CVD, including obesity and diabetes. However, transmission and end-organ mechanisms that explain PM2.5-induced impaired function in metabolic active organs are not completely understood. In this review, the main features of PM2.5 physicochemical characteristics related to PM2.5 ability to induce oxidative stress and inflammation will be presented. Hallmark and recent epidemiological and interventional studies will be summarized and discussed in the context of current air quality guidelines and legislation, knowledge gaps, and inequities. Lastly, mechanistic studies at the intersection between redox metabolism, inflammation, and function will be discussed, with focus on heart and adipose tissue alterations. By offering an integrated analysis of PM2.5-induced effects on cardiometabolic derangements, this review aims to contribute to a better understanding of the pathogenesis and potential interventions of air pollution-related CVD.

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.

Air Pollution, Built Environment, and Early Cardiovascular Disease

As the world's population becomes increasingly urbanized, there is growing concern about the impact of urban environments on cardiovascular health. Urban residents are exposed to a variety of adverse environmental exposures throughout their lives, including air pollution, built environment, and lack of green space, which may contribute to the development of early cardiovascular disease and related risk factors. While epidemiological studies have examined the role of a few environmental factors with early cardiovascular disease, the relationship with the broader environment remains poorly defined. In this article, we provide a brief overview of studies that have examined the impact of the environment including the built physical environment, discuss current challenges in the field, and suggest potential directions for future research. Additionally, we highlight the clinical implications of these findings and propose multilevel interventions to promote cardiovascular health among children and young adults.

Long-Term Exposure to Traffic-Related Air Pollution and Diabetes: A Systematic Review and Meta-Analysis

Objectives: We report results of a systematic review on the health effects of long-term traffic-related air pollution (TRAP) and diabetes in the adult population. Methods: An expert Panel appointed by the Health Effects Institute conducted this systematic review. We searched the PubMed and LUDOK databases for epidemiological studies from 1980 to July 2019. TRAP was defined based on a comprehensive protocol. Random-effects meta-analyses were performed. Confidence assessments were based on a modified Office for Health Assessment and Translation (OHAT) approach, complemented with a broader narrative synthesis. We extended our interpretation to include evidence published up to May 2022. Results: We considered 21 studies on diabetes. All meta-analytic estimates indicated higher diabetes risks with higher exposure. Exposure to NO₂ was associated with higher diabetes prevalence (RR 1.09; 95% CI: 1.02; 1.17 per 10 μg/m³), but less pronounced for diabetes incidence (RR 1.04; 95% CI: 0.96; 1.13 per 10 μg/m³). The overall confidence in the evidence was rated moderate, strengthened by the addition of 5 recently published studies. Conclusion: There was moderate evidence for an association of long-term TRAP exposure with diabetes.

What is the role of particulate matter 2.5 (PM2.5) on excess weight? A cross-sectional study in young Spanish people aged 2─14 years

PURPOSE

To assess the relationship between particulate matter 2.5 (PM2.5) levels and the prevalence of excess weight in a representative sample of Spanish young people aged 2─14 years.

METHODS

This was an ecological cross-sectional study using data from the 2017 wave of the Encuesta Nacional de Salud Española (ENSE), a nationally representative survey of the Spanish young and adult population. The final sample included 4378 young Spanish people (51.0% boys). The weight (kg) and height (cm) of the study participants were proxy-reported by parents or guardians. Excess weight was determined according to the age- and sex-criteria of the International Obesity Task Force. The PM_2.5 level was calculated as the annual monitoring data indicator for 2017 among the different regions in Spain. Logistic regression models were performed to estimate the relationships between PM_2.5 and weight.

RESULTS

Compared to young people located in regions with low levels of PM_2.5, those reporting greater odds for excess weight were found in regions with medium PM_2.5 (OR = 1.23; 95% CI, 1.02-1.49) and high PM_2.5 (OR = 1.35; 95% CI, 1.11-1.64) after adjusting for several sociodemographic, lifestyle and environmental covariates.

CONCLUSIONS

The prevalence of excess weight in young people was positively associated with PM_2.5 levels in Spain. This finding supports the hypothesis that air pollution exposure can result in excess weight in the young population, which, in turn, might lead to the development of metabolic disorders. From a socioecological perspective, a practical need to take environmental factors into consideration is important to address unhealthy weight in Spanish young people.

Association of long-term air pollution exposure with the risk of prediabetes and diabetes: Systematic perspective from inflammatory mechanisms, glucose homeostasis pathway to preventive strategies

BACKGROUND

Limited evidence suggests the association of air pollutants with a series of diabetic cascades including inflammatory pathways, glucose homeostasis disorder, and prediabetes and diabetes. Subclinical strategies for preventing such pollutants-induced effects remain unknown.

METHODS

We conducted a cross-sectional study in two typically air-polluted Chinese cities in 2018-2020. One-year average PM₁, PM_2.5, PM₁₀, SO₂, NO₂, and O₃ were calculated according to participants' residence. GAM multinomial logistic regression was performed to investigate the association of air pollutants with diabetes status. GAM and quantile g-computation were respectively performed to investigate individual and joint effects of air pollutants on glucose homeostasis markers (glucose, insulin, HbA1c, HOMA-IR, HOMA-B and HOMA-S). Complement C3 and hsCRP were analyzed as potential mediators. The ABCS criteria and hemoglobin glycation index (HGI) were examined for their potential in preventive strategy.

RESULTS

Long-term air pollutants exposure was associated with the risk of prediabetes [Prevalence ratio for O₃ (PR_O₃) = 1.96 (95% CI: 1.24, 3.03)] and diabetes [PR_PM₁ = 1.18 (95% CI: 1.05, 1.32); PR_PM_2.5 = 1.08 (95% CI: 1.00, 1.16); PR_O₃ = 1.35 (95% CI: 1.03, 1.74)]. PM₁, PM₁₀, SO₂ or O₃ exposure was associated with glucose-homeostasis disorder. For example, O₃ exposure was associated with increased levels of glucose [7.67% (95% CI: 1.75, 13.92)], insulin [19.98% (95% CI: 4.53, 37.72)], HOMA-IR [34.88% (95% CI: 13.81, 59.84)], and decreased levels of HOMA-S [-25.88% (95% CI: -37.46, -12.16)]. Complement C3 and hsCRP played mediating roles in these relationships with proportion mediated ranging from 6.95% to 60.64%. Participants with HGI ≤ -0.53 were protected from the adverse effects of air pollutants.

CONCLUSION

Our study provides comprehensive insights into air pollutant-associated diabetic cascade and suggests subclinical preventive strategies.

Associations and pathways between residential greenness and metabolic syndromes in Fujian Province

Background

Greenness exposure is beneficial to human health, but its potential mechanisms through which the risk for metabolic syndrome (MetS) could be reduced have been poorly studied. We aimed to estimate the greenness-MetS association in southeast China and investigate the independent and joint mediation effects of physical activity (PA), body mass index (BMI), and air pollutants on the association.

Methods

A cross-sectional study was conducted among the 38,288 adults based on the Fujian Behavior and Disease Surveillance (FBDS), established in 2018. MetS was defined as the presence of three or more of the five components: abdominal obesity, elevated triglyceride, reduced high-density lipoprotein cholesterol (HDL-C), high blood pressure, and elevated fasting glucose. The residential greenness exposure was measured as the 3-year mean values of the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) within the 250, 500, and 1,000 meters (m) buffer zones around the residential address of each participant. Logistic regression models were used to estimate the greenness-MetS association. The causal mediation analysis was used to estimate the independent and joint mediation effects of PA, BMI, particulate matter with an aerodynamic diameter of 2.5 μm (PM_2.5), particulate matter with an aerodynamic diameter ≤ 10 μm (PM₁₀), nitrogen dioxide (NO₂), and sulfur dioxide (SO₂).

Results

Each interquartile range (IQR) increase in greenness was associated with a decrease of 13% (OR = 0.87 [95%CI: 0.83, 0.92] for NDVI_500m and OR = 0.87 [95%CI: 0.82, 0.91] for EVI_500m) in MetS risk after adjusting for covariates. This association was stronger in those aged < 60 years (e.g., OR = 0.86 [95%CI: 0.81, 0.92] for NDVI_500m), males (e.g., OR = 0.73 [95%CI: 0.67, 0.80] for NDVI_500m), having an educational level of primary school or above (OR = 0.81 [95%CI: 0.74, 0.89] for NDVI_500m), married/cohabitation (OR = 0.86 [95%CI: 0.81, 0.91] for NDVI_500m), businessman (OR = 0.82 [95%CI: 0.68, 0.99] for NDVI_500m), other laborers (OR = 0.77 [95%CI: 0.68, 0.88] for NDVI_500m), and non-smokers (OR = 0.77 [95%CI: 0.70, 0.85] for NDVI_500m). The joint effect of all six mediators mediated about 48.1% and 44.6% of the total effect of NDVI_500m and EVI_500m on the MetS risk, respectively. Among them, BMI showed the strongest independent mediation effect (25.0% for NDVI_500m), followed by NO₂ and PM₁₀.

Conclusion

Exposure to residential greenness was associated with a decreased risk for MetS. PA, BMI, and the four air pollutants jointly interpreted nearly half of the mediation effects on the greenness-MetS association.

Effects of Ambient Particulate Matter (PM2.5) Exposure on Calorie Intake and Appetite of Outdoor Workers

Malaysia has been experiencing smoke-haze episodes almost annually for the past few decades. PM2.5 is the main component in haze and causes harmful impacts on health due to its small aerodynamic size. This study aimed to explore the implications of PM2.5 exposure on the dietary intake of working individuals. Two phased 13-weeks follow-up study was conducted involving 440 participants, consisting of two cohorts of outdoor and indoor workers. Ambient PM2.5 concentrations were monitored using DustTrakTM DRX Aerosol Monitor. Data on Simplified Nutritional Appetite Questionnaire (SNAQ) and 24 h diet recall were collected weekly. The highest PM2.5 concentration of 122.90 ± 2.07 µg/m3 was recorded in August, and it vastly exceeded the standard value stipulated by US EPA and WHO. SNAQ scores and calorie intake were found to be significantly (p < 0.05) associated with changes in PM2.5 exposure of outdoor workers. Several moderate and positive correlations (R-value ranged from 0.4 to 0.6) were established between SNAQ scores, calorie intake and PM2.5 exposure. Overall findings suggested that long hours of PM2.5 exposure affect personal dietary intake, potentially increasing the risk of metabolic syndromes and other undesired health conditions. The current policy should be strengthened to safeguard the well-being of outdoor workers.

Association between long-term air pollution exposure and insulin resistance independent of abdominal adiposity in Korean adults

Significant associations between air pollution (AP) and insulin resistance (IR) have been reported in limited populations or certain patient groups, but few studies have addressed this association in the general population, especially in Asians. Although abdominal fat is a major contributor to IR, previous studies have not fully controlled for its effect in the association between AP and IR. We investigated the association between exposure to AP and IR in Korean adults in the general population and whether this association is maintained even after controlling for the effects of abdominal fat, particularly visceral fat. This was a cross-sectional study. Data were obtained for Korean adults who participated in screening health checkups at Seoul National University Health Examination Center from 2006 to 2014. A total of 4251 men and women aged 22-84 years were included. IR was represented by the homeostasis model assessment of insulin resistance (HOMA-IR). Adiposity traits such as visceral adipose tissue (VAT) and subcutaneous adipose tissue areas were measured by computed tomography. We assessed the annual mean concentrations of air pollutants, including particulate matter with an aerodynamic diameter of 10 µm or less (PM₁₀), nitrogen dioxide, sulfur dioxide, and carbon monoxide. HOMA-IR was significantly associated with increased annual mean exposure to PM₁₀ in both men (β = 0.15; 95% CI 0.09, 0.22) and women (β = 0.16; 95% CI 0.09, 0.23), and these associations were maintained even after controlling for VAT area (both p < 0.05). The adjusted mean HOMA-IR increased gradually with the level of long-term PM₁₀ exposure (low, intermediate, and high exposure) (all p for trend < 0.001) in the subgroup analysis. After adjusting for possible confounding factors, including VAT area, the annual mean exposure to PM₁₀ was significantly associated with the presence of IR in both men (OR 1.18; 95% CI 1.03, 1.35) and women (OR 1.44; 95% CI 1.18, 1.76). Other air pollutants, such as NO₂, SO₂ and CO, did not show any significant associations with HOMA-IR or the presence of IR. Persistent exposure to PM₁₀ is the main independent risk factor for IR and exhibits a dose-dependent association regardless of visceral fatness in both men and women.

Longitudinal Associations of Air Pollution With Body Size and Composition in Midlife Women: The Study of Women's Health Across the Nation

OBJECTIVE

We examined longitudinal associations of air pollution exposure, including fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3), with weight, BMI, waist circumference, fat mass, lean mass, and proportion fat mass in midlife women.

RESEARCH DESIGN AND METHODS

The study population included 1,654 White, Black, Chinese, and Japanese women from the Study of Women's Health Across the Nation, with the baseline median age of 49.6 years, followed from 2000 to 2008. Annual air pollution exposures were assigned by linking residential addresses with hybrid estimates of air pollutant concentrations at 1-km2 resolution. Body size was measured, and body composition was measured using DXA at approximately annual visits. Linear mixed effects models were used to examine the associations between air pollution and body size and composition measures and whether these associations differed by physical activity.

RESULTS

After adjusting for potential confounders, an interquartile range increase in PM2.5 concentration (4.5 μg/m3) was associated with 4.53% (95% CI 3.85%, 5.22%) higher fat mass, 1.10% (95% CI 0.95%, 1.25%) higher proportion fat mass, and 0.39% (95% CI -0.77%, -0.01%) lower lean mass. Similar associations were also observed for NO2 and O3. Weaker associations of PM2.5 and NO2 with body composition were observed in participants who engaged in more physical activity.

CONCLUSIONS

Our analyses provide evidence that exposure to PM2.5, NO2, and O3, is adversely associated with body composition, including higher fat mass, higher proportional fat mass, and lower lean mass, highlighting their potential contribution to obesity.

Traffic-related air pollution, biomarkers of metabolic dysfunction, oxidative stress, and CC16 in children

BACKGROUND

Previous research has revealed links between air pollution exposure and metabolic syndrome in adults; however, these associations are less explored in children.

OBJECTIVE

This study aims to investigate the association between traffic-related air pollutants (TRAP) and biomarkers of metabolic dysregulation, oxidative stress, and lung epithelial damage in children.

METHODS

We conducted cross-sectional analyses in a sample of predominantly Latinx, low-income children (n = 218) to examine associations between air pollutants (nitrogen dioxide (NO₂), nitrogen oxides (NO_x), elemental carbon, polycyclic aromatic hydrocarbons, carbon monoxide (CO), fine particulates (PM_2.5)) and biomarkers of metabolic function (high-density lipoprotein (HDL), hemoglobin A1c (HbA1c), oxidative stress (8-isoprostane), and lung epithelial damage (club cell protein 16 (CC16)).

RESULTS

HDL cholesterol showed an inverse association with NO₂ and NO_x, with the strongest relationship between HDL and 3-month exposure to NO₂ (-15.4 mg/dL per IQR increase in 3-month NO₂, 95% CI = -27.4, -3.4). 8-isoprostane showed a consistent pattern of increasing values with 1-day and 1-week exposure across all pollutants. Non-significant increases in % HbA1c were found during 1-month time frames and decreasing CC16 in 3-month exposure time frames.

CONCLUSION

Our results suggest that TRAP is significantly associated with decreased HDL cholesterol in longer-term time frames and elevated 8-isoprostane in shorter-term time frames. TRAP could have the potential to influence lifelong metabolic patterns, through metabolic effects in childhood.

Determining the effect of air quality on activities of daily living disability: using tracking survey data from 122 cities in China

Background

Current research on activities of daily living (ADLs) disability has mostly focused on the analysis of demographic characteristics, while research on the microcharacteristics of individuals and the macroenvironment is relatively limited, and these studies solely concern the impact of air quality on individual health.

Methods

This study innovatively investigated the impact of air quality on ADL disability by matching micro data of individuals from the China Health and Retirement Longitudinal Study with data of urban environmental quality from 122 cities. In this study, an ordered panel logit model was adopted for the benchmark test, and the two-stage ordered probit model with IV was used for endogenous treatment.

Results

This innovative study investigated the impact of air quality on ADL disability by matching individual micro data from the China Health and Retirement Longitudinal Study with urban environmental quality data for 122 cities. The results showed that air quality significantly increased the probability of ADL disability. The positive and marginal effect of air quality on moderate and mild disability was higher. Generally, the marginal effect of air quality on residents’ health was negative. In terms of group heterogeneity, the ADL disability of individuals aged over 60 years, those in the high Gross Domestic Product (GDP) group, females, and those in the nonpilot long-term care insurance group was more affected by air quality, and the interaction between air quality and serious illness showed that the deterioration of air quality exacerbated the ADL disability caused by serious illness; that is, the moderating effect was significant.

Conclusions

According to the equilibrium condition of the individual health production function, the ADL disability caused by a 1% improvement in air quality is equivalent to the ADL disability caused by an 89.9652% reduction in serious illness, indicating that the effect of improved air quality is difficult to replace by any other method. Therefore, good air quality can not only reduce ADL disability directly but also reduce serious illness indirectly, which is equivalent to the reduction of ADL disability. This is called the health impact.

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.

Ambient air pollution during pregnancy and cardiometabolic biomarkers in cord blood

Prenatal air pollution exposure has been associated with adverse childhood cardiometabolic outcomes. It is unknown whether evidence of metabolic disruption associated with air pollution is identifiable at birth. We examined exposure to prenatal ambient air pollution and cord blood cardiometabolic biomarkers among 812 mother-infant pairs in the Healthy Start study.

DNA damage, serum metabolomic alteration and carcinogenic risk associated with low-level air pollution

Outdoor air pollution has been classified as carcinogenic to humans (Group 1) for lung cancer, but the underlying mechanism and key toxic components remain incompletely understood. Since DNA damage and metabolite alterations are associated with cancer progression, exploring potential mechanisms linking air pollution and cancer might be meaningful. In this study, a real-time ambient air exposure system was established to simulate the real-world environment of adult male SD rats in Beijing from June 13th, 2018, to October 8th, 2018. 8-OHdG in the urine, γ-H2AX in the lungs and mtDNA copy number in the peripheral blood were analyzed to explore DNA damage at different levels. Serum non-targeted metabolomics analysis was performed. Pair-wise spearman was used to explore the correlation between DNA damage biomarkers and serum differential metabolites. Carcinogenic risks of heavy metals and PAHs via inhalation were assessed according to US EPA guidelines. Results showed that PM_2.5 and O₃ were the major air pollutants in the exposure group and not detected in the control group. Compared with control group, higher levels of 8-OHdG, mtDNA copy number, γ-H2AX and PCNA-positive nuclei cells were observed in the exposure group. Histopathological evaluation suggested ambient air induced alveolar wall thickening and inflammatory cell infiltration in lungs. Perturbed metabolic pathways identified included glycolysis/gluconeogenesis metabolism, purine and pyrimidine metabolism, etc. γ-H2AX was positively correlated with serum ADP, 3-phospho-D-glyceroyl phosphate and N-acetyl-D-glucosamine. The BaPeq was 0.120 ng/m³. Risks of Cr(VI), As, V, BaP, BaA and BbF were above 1 × 10^-6. We concluded that low-level air pollution was associated with DNA damage and serum metabolomic alterations in rats. Cr(VI) and BaP were identified as key carcinogenic components in PM_2.5. Our results provided experimental evidence for hazard identification and risk assessment of low-level air pollution.

How does air quality affect residents' life satisfaction? Evidence based on multiperiod follow-up survey data of 122 cities in China

Since entering the new era, China's socialist contradiction has been transformed into the contradiction between the people's growing need for a better life and the unbalanced and inadequate development. How to improve the quality of people's life through the improvement of air quality has become an important content restricting social development and a key problem to be solved. Based on the life satisfaction (LS) method, this study takes air quality into the individual utility function, and through matching China Health and Retirement Longitudinal Study (CHARLS), two phases of microindividual tracking data with 122 urban environmental quality data innovatively investigate the impact of air quality on residents' LS and its income substitution effect. The results show that air quality significantly reduces residents' LS, among which, different air pollutants and comprehensive air quality AQI have significant negative effects. And PM10 has the highest marginal effect on different LS evaluation, SO2 has the smallest marginal effect, and AQI marginal effect is close to PM10. In terms of group heterogeneity, NO2 and SO2 have group influence differences in age group, regional economic group, gender group, and family per capita income group. But PM10 and AQI do not show group influence heterogeneity, and air quality has significant negative effect on LS of different groups. In addition, the interaction between air quality and income level shows that air quality strengthens the difference of residents' LS caused by income level difference. According to the equilibrium condition of residents' individual utility function, the improvement of air quality by 1% is equivalent to the improvement of residents' LS by 23.4402% of income. Firstly, air quality has an important impact on residents' LS, and different air pollutants have different effects. Secondly, the impact of air quality on LS of different groups is heterogeneous and mainly diversified in age group, regional economic group, gender group, and family per capital income group. Finally, there is substitution effect between air quality and regional GDP growth and household income, which affects residents' LS. Thirdly, the conclusion shows that the improvement of air quality is difficult to be replaced by other ways. Good air quality can not only directly improve residents' LS, but also has economic effect.

Does ozone inhalation cause adverse metabolic effects in humans? A systematic review

We utilized a practical, transparent approach for systematically reviewing a chemical-specific evidence base. This approach was used for a case study of ozone inhalation exposure and adverse metabolic effects (overweight/obesity, Type 1 diabetes [T1D], Type 2 diabetes [T2D], and metabolic syndrome). We followed the basic principles of systematic review. Studies were defined as "Suitable" or "Supplemental." The evidence for Suitable studies was characterized as strong or weak. An overall causality judgment for each outcome was then determined as either causal, suggestive, insufficient, or not likely. Fifteen epidemiologic and 33 toxicologic studies were Suitable for evidence synthesis. The strength of the human evidence was weak for all outcomes. The toxicologic evidence was weak for all outcomes except two: body weight, and impaired glucose tolerance/homeostasis and fasting/baseline hyperglycemia. The combined epidemiologic and toxicologic evidence was categorized as weak for overweight/obesity, T1D, and metabolic syndrome,. The association between ozone exposure and T2D was determined to be insufficient or suggestive. The streamlined approach described in this paper is transparent and focuses on key elements. As systematic review guidelines are becoming increasingly complex, it is worth exploring the extent to which related health outcomes should be combined or kept distinct, and the merits of focusing on critical elements to select studies suitable for causal inference. We recommend that systematic review results be used to target discussions around specific research needs for advancing causal determinations.

Health risk assessment of PM2.5 on walking trips

PM_2.5 has an impact on residents' physical health during travelling, especially walking completely exposed to the environment. In order to obtain the specific impact of PM_2.5 on walking, 368 healthy volunteers were selected and they were grouped according to gender and age. In the experiment, the heart rate change rate (HR%) is taken as test variable. According to receiver operating characteristic (ROC) curve, the travel is divided into two states: safety and risk. Based on this, a binary logit model considering Body Mass Index (BMI) is established to determine the contribution of PM_2.5 concentration and body characteristics to travel risk. The experiment was conducted on Chang'an Middle Road in Xi'an City. The analysis results show that the threshold of HR% for safety and risk ranges from 31.1 to 40.1%, and that of PM_2.5 concentration ranges from 81 to 168 μg/m³. The probability of risk rises 5.8% and 11.4%, respectively, for every unit increase in PM_2.5 concentration and HR%. Under same conditions, the probability of risk for male is 76.8% of that for female. The probability of risk for youth is 67.5% of that for middle-aged people, and the probability of risk for people with BMI in healthy range is 72.1% of that for non-healthy range. The research evaluates risk characteristics of walking in particular polluted weather, which can improve residents' health level and provide suggestions for travel decision while walking.

Air pollution and meteorological conditions during gestation and type 1 diabetes in offspring

BACKGROUND

Growing evidence indicates that air pollution is capable of disrupting the immune system and therefore, might be associated with an onset of Type 1 diabetes (T1D).

OBJECTIVES

We explored possible links of T1D with ambient exposures in the population of southern Israel, characterized by hot and dry climate and frequent dust storms.

METHODS

We conducted a matched nested case-control study where exposure to environmental pollutants during gestation in T1D cases was compared to that of healthy children. Up to 10 controls were matched to every case by age, gender and ethnicity, in all 362 cases and 3512 controls. Measurements of pollutants' concentrations, nitrogen dioxide (NO₂), sulphur dioxide (SO₂), ozone (O₃) and particulate matter of size less than 10 and 2.5 μm in diameter (PM₁₀ and PM_2.5), as well as the mean daily measurements of meteorological conditions were obtained from the local monitoring stations. The association between T1D and pollution, solar radiation (SR), temperature and relative humidity was adjusted for socioeconomic status, temperature, maternal age and pre-gestational maternal DM, using conditional logistic regression. The environmental exposures were presented as indicators of quartiles averaged over whole pregnancy and by trimesters.

RESULTS

Exposure to ozone and solar radiation during gestation were both associated with the T1D in offspring, although at borderline significance. Compared to the lowest quartile, the odds ratio (OR) for exposure to 3rd and 4th quartile of O₃ was equal 1.61 (95%CI: 0.95; 2.73) and 1.45 (95%CI: 0.83; 2.53), respectively. Likewise, the ORs for exposure to SR were equal 1.83 (95%CI: 0.92; 3.64), 2.54 (95%CI: 1.21; 5.29) and 2.06 (95%CI: 0.95; 4.45) for to 2nd, 3rd and 4th quartiles, respectively. Exposure to SO₂ followed a dose-response pattern, but was not statistically significant. Other environmental factors were not independently related to T1D. Analysis of exposures one year prior to the disease onset indicated a positive association between T1D and SR.

CONCLUSIONS

We showed that exposure to high ozone levels and solar radiation during gestation might be related to the T1D. More scientific evidence needs to accumulate to support the study findings.

Ambient air pollution and endocrinologic disorders in childhood

Ambient air pollution has been proposed as an important environmental risk factor that increases global mortality and morbidity. Over the past decade, several human and animal studies have reported an association between exposure to air pollution and altered metabolic and endocrine systems in children. However, the results for these studies were mixed and inconclusive and did not demonstrate causality because different outcomes were observed due to different study designs, exposure periods, and methodologies for exposure measurements. Current proposed mechanisms include altered immune response, oxidative stress, neuroinflammation, inadequate placental development, and epigenetic modulation. In this review, we summarized the results of previous pediatric studies that reported effects of prenatal and postnatal air pollution exposure on childhood type 1 diabetes mellitus, obesity, insulin resistance, thyroid dysfunction, and timing of pubertal onset, along with underlying related mechanisms.

Effect of sulfur dioxide exposure on histopathology and morphometry of pancreatic islet cells and glycemic indices in Wistar rats

Sulfur dioxide (SO₂) is a ubiquitous air pollutant. Recent studies suggest that SO₂ is a momentous risk factor for diabetes mellitus (DM). The present investigation aimed to evaluate the effects of SO₂ exposure on histopathology and morphometry of pancreatic islet cells and serum glycemic indices in rats. Sixteen male Wistar rats were divided equally into SO₂ and control groups. SO₂ group was exposed to 10 parts per million (ppm) SO₂ for 5 weeks (6 days a week, 3 h/day) and control group to filtered air for the same time as SO₂ group. Blood serums were collected and pancreatic tissue isolated. Glycemic indices were measured. Pathological and morphometric changes were studied in the pancreatic tissues. Exposure to SO₂ caused a significant increase in blood glucose but did not significantly change insulin and HbA1c serum levels and HOMA-IR. There were significant differences in vascular congestion (p= 0.02) and insulitis (p= 0.04) between the groups. SO₂ inhalation significantly reduced beta cell number and beta-alpha cell ratio compared with the control group (p=0.03 and p<0.0001, respectively). These findings suggest that SO₂ exposure damages pancreatic tissue which subsequently influences either the incidence of DM or the trend of diabetic complications.

Associations of residing greenness and long-term exposure to air pollution with glucose homeostasis markers

BACKGROUND

Although long-term exposure to higher air pollutants and lower residing greenness related to disorders of glucose homeostasis have been reported, their interaction effects on glucose homeostasis in developing countries remained unclear.

METHODS

A total of 35, 482 participants were obtained from the Henan Rural Cohort (n = 39, 259). Exposure to air pollutants (PM₁, PM_2.5, PM₁₀ and NO₂) were predicted by using a spatiotemporal model-based on satellites data. Residing greenness was reflected by Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI) which were derived from satellites data. Independent associations of single or mixture of air pollutant or residing greenness with glucose homeostasis markers were analyzed by quantile regression models and quantile g (qg)-computation method, respectively. Furthermore, interaction effects of residing greenness and air pollution on glucose homeostasis markers were analyzed by generalized additive models.

RESULTS

Positive associations of single or mixture of air pollutants (PM₁, PM_2.5, PM₁₀ or NO₂) with fasting plasma glucose (FPG) were observed, while negative associations of single or mixture of air pollutants with insulin or HOMA-β were observed. Residing greenness was negatively associated with FPG but positively related to insulin or HOMA-β. Quantile regression revealed the heterogeneity were observed in the associations the residing greenness or air pollutants with glucose homeostasis markers (insulin or HOMA-β) across deciles of the glucose homeostasis markers distributions. Furthermore, joint associations of single air pollutant and residing greenness on glucose homeostasis markers were found.

CONCLUSIONS

The results indicated that exposure to air pollution had negative effect on glucose homeostasis markers and these effects may be modified by living in higher green space. These findings suggest that increased residing greenness and air pollution control may have joint effect on decreased the risk of diabetes.

CLINICAL TRIAL REGISTRATION

The Henan Rural Cohort study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699, http://www.chictr.org.cn/showproj.aspx?proj=11375).

Effect of Air Pollution on Obesity in Children: A Systematic Review and Meta-Analysis

Air pollution exposure has been identified as being associated with childhood obesity. Nevertheless, strong evidence of such an association is still lacking. To analyze whether air pollution exposure affects childhood obesity, we conducted a systematic review and meta-analysis utilizing the PRISMA guidelines. Of 7343 studies identified, eight studies that investigated the effects of air pollutant characteristics, including PM_2.5, PM₁₀, PM_coarse, PM_absorbance, NO_x, and NO₂, on childhood obesity were included. The polled effects showed that air pollution is correlated with a substantially increased risk of childhood obesity. PM_2.5 was found to be associated with a significantly increased risk (6%) of childhood obesity (OR 1.06, 95% CI 1.02–1.10, p = 0.003). In addition, PM₁₀, PM_{2.5absorbance}, and NO₂ appeared to significantly increase the risk of obesity in children (OR 1.07, 95% CI 1.04–1.10, p < 0.00; OR 1.23, 95% CI 1.06–1.43, p = 0.07; and OR 1.10, 95% CI 1.04–1.16, p < 0.001, respectively). PM_coarse and NO_x also showed trends towards being associated with an increased risk of childhood obesity (OR 1.07, 95% CI 0.95–1.20, p = 0.291, and OR 1.00, 95% CI 0.99–1.02, p = 0.571, respectively). Strong evidence was found to support the theory that air pollution exposure is one of the factors that increases the risk of childhood obesity.

Ambient air pollutants are associated with morning serum cortisol in overweight and obese Latino youth in Los Angeles

BACKGROUND

Hypothalamic-pituitary-adrenal (HPA)-axis dysfunction has been associated with a variety of mental health and cardio-metabolic disorders. While causal models of HPA-axis dysregulation have been largely focused on either pre-existing health conditions or psychosocial stress factors, recent evidence suggests a possible role for central nervous system activation via air pollutants, such as nitrogen dioxide (NO2), ozone (O3) and particulate matter (PM). Therefore, in an observational study of Latino youth, we investigated if monthly ambient NO2, O3, and PM with aerodynamic diameter ≤ 2.5 (PM2.5) exposure were associated with morning serum cortisol levels.

METHODS

In this cross-sectional study, morning serum cortisol level was assessed after a supervised overnight fast in 203 overweight and obese Latino children and adolescents (female/male: 88/115; mean age: 11.1 ± 1.7 years; pre-pubertal/pubertal/post-pubertal: 85/101/17; BMI z-score: 2.1 ± 0.4). Cumulative concentrations of NO2, O3 and PM2.5 were spatially interpolated at the residential addresses based on measurements from community monitors up to 12 months prior to testing. Single and multi-pollutant linear effects models were used to test the cumulative monthly lag effects of NO2, O3, and PM2.5 on morning serum cortisol levels after adjusting for age, sex, seasonality, social position, pubertal status, and body fat percent by DEXA.

RESULTS

Single and multi-pollutant models showed that higher O3 exposure (derived from maximum 8-h exposure windows) in the prior 1-7 months was associated with higher serum morning cortisol (p < 0.05) and longer term PM2.5 exposure (4-10 months) was associated with lower serum morning cortisol levels (p < 0.05). Stratification by pubertal status showed associations in pre-pubertal children compared to pubertal and post-pubertal children. Single, but not multi-pollutant, models showed that higher NO2 over the 4-10 month exposure period associated with lower morning serum cortisol (p < 0.05).

CONCLUSIONS

Chronic ambient NO2, O3 and PM2.5 differentially associate with HPA-axis dysfunction, a mechanism that may serve as an explanatory pathway in the relationship between ambient air pollution and metabolic health of youth living in polluted urban environments. Further research that uncovers how ambient air pollutants may differentially contribute to HPA-axis dysfunction are warranted.

Traffic-related air pollution is associated with glucose dysregulation, blood pressure, and oxidative stress in children

BACKGROUND

Metabolic syndrome increases the risk of cardiovascular disease in adults. Antecedents likely begin in childhood and whether childhood exposure to air pollution plays a contributory role is not well understood.

OBJECTIVES

To assess whether children's exposure to air pollution is associated with markers of risk for metabolic syndrome and oxidative stress, a hypothesized mediator of air pollution-related health effects.

METHODS

We studied 299 children (ages 6-8) living in the Fresno, CA area. At a study center visit, questionnaire and biomarker data were collected. Outcomes included hemoglobin A1c (HbA1c), urinary 8-isoprostane, systolic blood pressure (SBP), and BMI. Individual-level exposure estimates for a set of four pollutants that are constituents of traffic-related air pollution (TRAP) - the sum of 4-, 5-, and 6-ring polycyclic aromatic hydrocarbon compounds (PAH456), NO₂, elemental carbon, and fine particulate matter (PM_2.5) - were modeled at the primary residential location for 1-day lag, and 1-week, 1-month, 3-month, 6-month, and 1-year averages prior to each participant's visit date. Generalized additive models were used to estimate associations between each air pollutant exposure and outcome.

RESULTS

The study population was 53% male, 80% Latinx, 11% Black and largely low-income (6% were White and 3% were Asian/Pacific Islander). HbA1c percentage was associated with longer-term increases in TRAP; for example a 4.42 ng/m³ increase in 6-month average PAH456 was associated with a 0.07% increase (95% CI: 0.01, 0.14) and a 3.62 μg/m³ increase in 6-month average PM_2.5 was associated with a 0.06% increase (95% CI: 0.01, 0.10). The influence of air pollutants on blood pressure was strongest at 3 months; for example, a 6.2 ppb increase in 3-month average NO₂ was associated with a 9.4 mmHg increase in SBP (95% CI: 2.8, 15.9). TRAP concentrations were not significantly associated with anthropometric or adipokine measures. Short-term TRAP exposure averages were significantly associated with creatinine-adjusted urinary 8-isoprostane.

DISCUSSION

Our results suggest that both short- and longer-term estimated individual-level outdoor residential exposures to several traffic-related air pollutants, including ambient PAHs, are associated with biomarkers of risk for metabolic syndrome and oxidative stress in children.

Ultrafine particles altered gut microbial population and metabolic profiles in a sex-specific manner in an obese mouse model

Emerging evidence has highlighted the connection between exposure to air pollution and the increased risk of obesity, metabolic syndrome, and comorbidities. Given the recent interest in studying the effects of ultrafine particle (UFP) on the health of obese individuals, this study examined the effects of gastrointestinal UFP exposure on gut microbial composition and metabolic function using an in vivo murine model of obesity in both sexes. UFPs generated from light-duty diesel engine combustion of petrodiesel (B0) and a petrodiesel/biodiesel fuel blend (80:20 v/v, B20) were administered orally. Multi-omics approaches, including liquid chromatography-mass spectrometry (LC-MS) based targeted metabolomics and 16S rRNA gene sequence analysis, semi-quantitatively compared the effects of 10-day UFP exposures on obese C57B6 mouse gut microbial population, changes in diversity and community function compared to a phosphate buffer solution (PBS) control group. Our results show that sex-specific differences in the gut microbial population in response to UFP exposure can be observed, as UFPs appear to have a differential impact on several bacterial families in males and females. Meanwhile, the alteration of seventy-five metabolites from the gut microbial metabolome varied significantly (ANOVA p < 0.05) across the PBS control, B0, and B20 groups. Multivariate analyses revealed that the fuel-type specific disruption to the microbial metabolome was observed in both sexes, with stronger disruptive effects found in females in comparison to male obese mice. Metabolic signatures of bacterial cellular oxidative stress, such as the decreased concentration of nucleotides and lipids and increased concentrations of carbohydrate, energy, and vitamin metabolites were detected. Furthermore, blood metabolites from the obese mice were differentially affected by the fuel types used to generate the UFPs (B0 vs. B20).

The effect of ambient ozone on glucose-homoeostasis: A prospective study of non-diabetic older adults in Beijing

OBJECTIVE

To investigate potential effects of short- and medium-term exposure to low levels of ozone (O3) on glucose-homeostasis in non-diabetic older adults.

METHODS

166 non-diabetic, older participants in Beijing were deemed eligible to partake in this longitudinal population-based study. Observations were recorded on three separate occasions from November 2016 up until January 2018. Concentrations of outdoor O3 were monitored throughout the study period. Biomarkers indicative of glucose-homeostasis, including fasting blood glucose, insulin, HbAlc, glycated albumin percentage (glycated albumin/albumin), HOMA-IR and HOMA-B were measured at 3 sessions. A linear mixed effects model with random effects was adopted to quantify the effect of O3 across a comprehensive set of glucose-homeostasis markers.

RESULTS

Short-term O3 exposure positively associated with increased fasting blood glucose, insulin, HOMA-IR and HOMA-B. The effect on glucose occurred at 3-, 5-, 6- and 7-days, although the largest effect manifested on 6-days (5.6%, 95% CI: 1.4, 9.9). Significant associations with both insulin and HOMA-IR were observed on the 3- and 4-days. For HOMA-B, positive associations were identified from 3- to 7-days with estimates ranging from 40.0% (95% CI: 2.3, 91.5) to 83.1% (95% CI: 25.3, 167.5). Stratification suggests that women may be more susceptible to short-term O3 exposure. There does not appear to be a significant association between O3 and glucose-homeostasis in medium-term exposures.

CONCLUSIONS

In this study, we found that O3 exposure is at least partially associated with type II diabetes in older adults with no prior history of this condition. O3 therefore appears to be a potential risk factor, which is a particular concern when we consider the rise in global concentrations. Evidence also suggests that women may be more susceptible to short-term O3 exposure although we are not quite sure why. Future research may look to investigate this phenomenon further.

Longitudinal associations between ambient air pollution and insulin sensitivity: results from the KORA cohort study

BACKGROUND

Impaired insulin sensitivity could be an intermediate step that links exposure to air pollution to the development of type 2 diabetes. However, longitudinal associations of air pollution with insulin sensitivity remain unclear. Our study investigated the associations of long-term air pollution exposure with the degree and rate of change of insulin sensitivity.

METHODS

In this longitudinal study, we analysed data from the Cooperative Health Research in the Region of Augsburg (KORA) cohort from Augsburg, Germany, which recruited participants aged 25-74 years in the survey between 1999 and 2001 (KORA S4), with two follow-up examinations in 2006-08 (KORA F4) and 2013-14 (KORA FF4). Serum concentrations of fasting insulin and glucose, and homoeostasis model assessment of insulin resistance (HOMA-IR, a surrogate measure of insulin sensitivity) and β-cell function (HOMA-B, a surrogate marker for fasting insulin secretion) were assessed at up to three visits between 1999 and 2014. Annual average air pollutant concentrations at the residence were estimated by land-use regression models. We examined the associations of air pollution with repeatedly assessed biomarker levels using mixed-effects models, and we assessed the associations with the annual rate of change in biomarkers using quantile regression models.

FINDINGS

Among 9620 observations from 4261 participants in the KORA cohort, we included 6008 (62·5%) observations from 3297 (77·4%) participants in our analyses. Per IQR increment in annual average air pollutant concentrations, HOMA-IR significantly increased by 2·5% (95% CI 0·3 to 4·7) for coarse particulate matter, by 3·1% (0·9 to 5·3) for PM_2·5, by 3·6% (1·0 to 6·3) for PM_{2·5absorbance}, and by 3·2% (0·6 to 5·8) for nitrogen dioxide, and borderline significantly increased by 2·2% (-0·1 to 4·5) for ozone, whereas it did not significantly increase for the whole range of ultrafine particles. Similar positive associations in slightly smaller magnitude were observed for HOMA-B and fasting insulin levels. In addition, air pollutant concentrations were positively associated with the annual rate of change in HOMA-IR, HOMA-B, and fasting insulin. Neither the level nor the rate of change of fasting glucose were associated with air pollution exposure.

INTERPRETATION

Our study indicates that long-term air pollution exposure could contribute to the development of insulin resistance, which is one of the key factors in the pathogenesis of type 2 diabetes.

FUNDING

German Federal Ministry of Education and Research.

Impacts of ambient air pollution on glucose metabolism in Korean adults: a Korea National Health and Nutrition Examination Survey study

BACKGROUND

Exposure to air pollution was reported to affect glucose metabolism, increasing the risk of diabetes mellitus. We conducted an epidemiological study on glucose metabolism and air pollution by exploring the levels of fasting blood glucose (FBG) and hemoglobin A1c (HbA1c) with changes in ambient air quality, depending on the characteristics of the susceptible population.

METHODS

We carried out a cross-sectional analysis of a nationally representative sample of 10,014 adults (4267 in male and 5747 in female) from the Korea National Health and Nutrition Examination Survey in 2012 and 2013 along with data from the Korean Air Quality Forecasting System. The analysis was performed using a generalized linear model stratified by sex, age, and presence of diabetes. We assessed the changes in FBG and HbA1c associated with exposures to particulate matter (PM₁₀), fine particulate matter (PM_2.5), and nitrogen dioxide (NO₂) after controlling for confounders.

RESULTS

There were 1110 participants with diabetes (557 in male and 553 in female). Overall, the FBG level increased by 7.83 mg/dL (95% confidence interval [CI]: 2.80-12.87) per interquartile range (IQR) increment of NO₂, 5.32 mg/dL (95% CI: 1.22-9.41) per IQR increment of PM₁₀ at a moving average of 0-6 days, and 4.69 mg/dL (95% CI: 0.48-8.91) per IQR increment of PM_2.5 at a moving average of 0-5 days. HbA1c increased by 0.57% (95% CI: 0.04-1.09) per IQR increment of PM₁₀ at a moving average of 0-60 days and 0.34% (95% CI: 0.04-0.63) per IQR increment of PM_2.5 at a moving average of 0-75 days. The change in FBG and HbA1c increased more in the diabetic group, especially in males aged 65 years or more. There was a strong association between elevation in diabetes-related parameters and exposure to air pollution.

CONCLUSIONS

Our study provides scientific evidence supporting that short- and mid-term exposure to air pollution is associated with changes in biological markers related to diabetes. This finding suggests that the impact of air pollution should be reflected in chronic disease management when establishing local health care policies.

Developmental Origins of Health and Disease: Impact of environmental dust exposure in modulating microbiome and its association with non-communicable diseases

Non-communicable diseases (NCDs) including obesity, diabetes, and allergy are chronic, multi-factorial conditions that are affected by both genetic and environmental factors. Over the last decade, the microbiome has emerged as a possible contributor to the pathogenesis of NCDs. Microbiome profiles were altered in patients with NCDs, and shift in microbial communities was associated with improvement in these health conditions. Since the genetic component of these diseases cannot be altered, the ability to manipulate the microbiome holds great promise for design of novel therapies in the prevention and treatment of NCDs. Together, the Developmental Origins of Health and Disease concept and the microbial hypothesis propose that early life exposure to environmental stimuli will alter the development and composition of the human microbiome, resulting in health consequences. Recent studies indicated that the environment we are exposed to in early life is instrumental in shaping robust immune development, possibly through modulation of the human microbiome (skin, airway, and gut). Despite much research into human microbiome, the origin of their constituent microbiota remains unclear. Dust (also known as particulate matter) is a key determinant of poor air quality in the modern urban environment. It is ubiquitous and serves as a major source and reservoir of microbial communities that modulates the human microbiome, contributing to health and disease. There are evidence that reported significant associations between environmental dust and NCDs. In this review, we will focus on the impact of dust exposure in shaping the human microbiome and its possible contribution to the development of NCDs.

Concomitant exposure to area-level poverty, ambient air volatile organic compounds, and cardiometabolic dysfunction: a cross-sectional study of U.S. adolescents

PURPOSE

A key to better understanding the influence of the place of residence on cardiometabolic function is the effect of concomitant exposure to both air pollution and residence in economically marginalized areas. We hypothesized that, among adolescents, the association between air pollution and cardiometabolic function is exacerbated among residents of economically marginalized areas.

METHODS

In this cross-sectional study, individual-level data on cardiometabolic function collected from a representative sample of U.S. adolescents in the National Health and Nutrition Examination Survey (n = 10,415) were merged with data on area-level poverty (U.S. decennial survey and American Community Survey) and air pollution levels (National-Scale Air Toxics Assessment ) using contemporary census-tract identifiers. We excluded respondents who were pregnant, had hypertension or diabetes or using medication for hypertension or diabetes, or with missing data on outcome variables.

RESULTS

We observed a significant interaction between area-level poverty and air pollution. Among residents of high-poverty areas, exposure to high levels of air pollution predicted a 30% elevated odds of cardiometabolic dysfunction (OR = 1.30; 95% CI: 1.04, 1.61), whereas in low-poverty areas, exposure to high levels of air pollution was not associated with elevated odds of cardiometabolic dysfunction (OR = 1.04; 95% CI: 0.85, 1.28).

CONCLUSIONS

Our findings suggest that the cardiometabolic consequences of air pollution are more readily realized among residents of economically marginalized areas. Structural remedies are discussed.

Associations of air pollution with obesity and body fat percentage, and modification by polygenic risk score for BMI in the UK Biobank

Air pollution has consistently been associated with cardiometabolic outcomes, although associations with obesity have only been recently reported. Studies of air pollution and adiposity have mostly relied on body mass index (BMI) rather than body fat percentage (BF%), and most have not accounted for noise as a possible confounder. Additionally, it is unknown whether genetic predisposition for obesity increases susceptibility to the obesogenic effects of air pollution. To help fill these gaps, we used the UK Biobank, a large, prospective cohort study in the United Kingdom, to explore the relationship between air pollution and adiposity, and modification by a polygenic risk score for BMI. We used 2010 annual averages of air pollution estimates from land use regression (NO₂, NO_X, PM_2.5, PM_{2.5absorbance}, PM_2.5-10, PM₁₀), traffic intensity (TI), inverse distance to road (IDTR), along with examiner-measured BMI, waist-hip-ratio (WHR), and impedance measures of BF%, which were collected at enrollment (2006-2010, n = 473,026) and at follow-up (2012-2013, n = 19,518). We estimated associations of air pollution with BMI, WHR, and BF% at enrollment and follow-up, and with obesity, abdominal obesity, and BF%-obesity at enrollment and follow-up. We used linear and logistic regression and controlled for noise and other covariates. We also assessed interactions of air pollution with a polygenic risk score for BMI. On average, participants at enrollment were 56 years of age, 54% were female, and 32% had completed college or a higher degree. Almost all participants (~95%) were white. All air pollution measures except IDTR were positively associated with at least one continuous measure of adiposity at enrollment. However, NO₂ was negatively associated with BMI but positively associated with WHR at enrollment, and IDTR was also negatively associated with BMI. At follow-up (controlling for enrollment adiposity), we observed positive associations for PM_2.5-10 with BMI, PM₁₀ with BF%, and TI with BF% and BMI. Associations were similar for binary measures of adiposity, with minor differences for some pollutants. Associations of NO_X, NO₂, PM_{2.5absorbance}, PM_2.5 and PM₁₀, with BMI at enrollment, but not at follow-up, were stronger among individuals with higher BMI polygenic risk scores (interaction p <0.05). In this large, prospective cohort, air pollution was associated with several measures of adiposity at enrollment and follow-up, and associations with adiposity at enrollment were modified by a polygenic risk score for obesity.

Air pollution exposure is associated with the gut microbiome as revealed by shotgun metagenomic sequencing

Animal work indicates exposure to air pollutants may alter the composition of the gut microbiota. This study examined relationships between air pollutants and the gut microbiome in young adults residing in Southern California. Our results demonstrate significant associations between exposure to air pollutants and the composition of the gut microbiome using whole-genome sequencing. Higher exposure to 24-hour O3 was associated with lower Shannon diversity index, higher Bacteroides caecimuris, and multiple gene pathways, including L-ornithine de novo biosynthesis as well as pantothenate and coenzyme A biosynthesis I. Among other pollutants, higher NO2 exposure was associated with fewer taxa, including higher Firmicutes. The percent variation in gut bacterial composition that was explained by air pollution exposure was up to 11.2% for O3 concentrations, which is large compared to the effect size for many other covariates reported in healthy populations. This study provides the first evidence of significant associations between exposure to air pollutants and the compositional and functional profile of the human gut microbiome. These results identify O3 as an important pollutant that may alter the human gut microbiome.

The relationship between long-term exposure to PM2.5 and fasting plasma glucose levels in Chinese children and adolescents aged 6-17 years: A national cross-sectional study

BACKGROUND

Previous studies investigating the association between PM_2.5 exposure and fasting plasma glucose levels (FPGLs) are mostly limited to short- and mid-term PM_2.5 exposure and lack adjustments for key confounders in adult research.

OBJECTIVES

Exploring the relationship between seven years long-term PM_2.5 exposure and FPGLs in Chinese children and adolescents aged 6-17 years.

METHODS

Between September 2013 and December 2013, 16,489 participants aged 6-17 years were recruited using a four-staged, stratified, cluster sampling strategy from 7 provinces, autonomous regions and municipalities of mainland China. A generalized linear mixed model (GLMM) was used to estimate the relationship between annual PM_2.5 exposure (2007-2013) and FPGLs stratified by sex and one-year age increments. Sociodemographic characteristics, living with both parents, early-life factors, behaviours, and infection symptoms were gradually adjusted from the crude model to regression model 6, and BMI was adjusted for in model 7.

RESULTS

The annual concentration of PM_2.5 was 56.23 (±12.99) μg/m³. The mean FPGLs in the 8551 boys (4.75 mmol/L ± 0.52) was significantly higher than that in the 8194 girls (4.63 mmol/L ± 0.48) (P < 0.0001). In model 6, for every 10 μg/m3 increase in PM_2.5 exposure, the FPGLs in boys and girls increased by 0.048 (95% CIs 0.031 to 0.065) mmol/L (P < 0.0001) and 0.054 (95% CIs 0.039 to 0.069) mmol/L (P < 0.0001), respectively. The FPGLs were significantly positively associated with long-term PM_2.5 exposure at the ages of 12, 15 and 16 years in both the boys and girls and exhibited age differences in model 7. The prevalence of impaired fasting plasma glucose (IFP) and diabetes decreased by 0.8% when the exposure concentration of PM_2.5 was reduced by 10 μg/m³ in model 6, which assessed the negative effects of PM_2.5 exposure and revealed that 1,298,920 children and adolescents could have been protected from IFP and diabetes in 2013 in China.

CONCLUSIONS

Long-term PM_2.5 exposure may be an independent risk factor of elevated FPGLs. The adverse effect of PM_2.5 exposure on FPGLs in children and adolescents could appear after 10 years of cumulative exposure. The precise intervention time was revealed as approximately 12 and 11 years in boys and girls, respectively. There are great public health implications associated with early prevention strategies for the eradication of the negative effects of long-term exposure to PM_2.5 on FPGLs.

Cumulative Lifetime Burden of Cardiovascular Disease From Early Exposure to Air Pollution

The disease burden associated with air pollution continues to grow. The World Health Organization (WHO) estimates ≈7 million people worldwide die yearly from exposure to polluted air, half of which-3.3 million-are attributable to cardiovascular disease (CVD), greater than from major modifiable CVD risks including smoking, hypertension, hyperlipidemia, and diabetes mellitus. This serious and growing health threat is attributed to increasing urbanization of the world's populations with consequent exposure to polluted air. Especially vulnerable are the elderly, patients with pre-existing CVD, and children. The cumulative lifetime burden in children is particularly of concern because their rapidly developing cardiopulmonary systems are more susceptible to damage and they spend more time outdoors and therefore inhale more pollutants. World Health Organization estimates that 93% of the world's children aged <15 years-1.8 billion children-breathe air that puts their health and development at risk. Here, we present growing scientific evidence, including from our own group, that chronic exposure to air pollution early in life is directly linked to development of major CVD risks, including obesity, hypertension, and metabolic disorders. In this review, we surveyed the literature for current knowledge of how pollution exposure early in life adversely impacts cardiovascular phenotypes, and lay the foundation for early intervention and other strategies that can help prevent this damage. We also discuss the need for better guidelines and additional research to validate exposure metrics and interventions that will ultimately help healthcare providers reduce the growing burden of CVD from pollution.

Effects of ambient particulate matter on fasting blood glucose: A systematic review and meta-analysis

Studies have found that ambient particulate matter (PM) affects fasting blood glucose. However, the results are not consistent. We conducted a systematic review and meta-analysis to determine the relationship between PM with an aerodynamic diameter of 10 μm or less (PM₁₀) and PM with an aerodynamic diameter of 2.5 μm or less (PM_2.5) and fasting blood glucose. We searched PubMed, Web of Science, the Wanfang Database and the China National Knowledge Infrastructure up to April 1, 2019. A total of 24 papers were included in the review, and 17 studies with complete or convertible quantitative information were included in the meta-analysis. The studies were divided into groups by PM size fractions (PM₁₀ and PM_2.5) and length of exposure. Long-term exposures were based on annual average concentrations, and short-term exposures were those lasting less than 28 days. In the long-term exposure group, fasting blood glucose increased 0.10 mmol/L (95% CI: 0.02, 0.17) per 10 μg/m³ of increased PM₁₀ and 0.23 mmol/L (95% CI: 0.01, 0.45) per 10 μg/m³ of increased PM_2.5. In the short-term exposure group, fasting blood glucose increased 0.02 mmol/L (95% CI: -0.01, 0.04) per 10 μg/m³ of increased PM₁₀ and 0.08 mmol/L (95% CI: 0.04, 0.11) per 10 μg/m³ of increased PM_2.5. Further prospective studies are needed to explore the relationship between ambient PM exposure and fasting blood glucose.

Long-term exposure to PM2.5 and fasting plasma glucose in non-diabetic adolescents in Yogyakarta, Indonesia

BACKGROUND

Indonesia is facing serious air pollution. However, very few studies have been conducted to examine the health risks of air pollution in Indonesia, particularly for adolescents.

OBJECTIVE

To assess the association between long-term exposure to ambient particles with a diameter of <2.5 μm (PM_2.5) and fasting plasma glucose (FPG) in adolescents.

METHODS

A cross-sectional study was conducted in 482 adolescents aged 14-18 years in Yogyakarta, Indonesia in 2016. We finally included 469 (97.30%) participants who had no missing data for data analysis. We collected individual data on socio-demographics, behavioral habits, and health information through standardized questionnaires. Satellite-based PM_2.5 concentrations from 2013 to 2016 were assigned based on participants' residential addresses. The association between PM_2.5 and FPG was examined using a generalized linear regression model while FPG was modeled as a continuous variable. An ordered logistic regression model was used to assess the relationship between PM_2.5 and FPG categories.

RESULTS

Every 1 μg/m³ increase in PM_2.5 was associated with a 0.34 mg/dL [95 confidence interval (95% CI): 0.08 mg/dL, 0.59 mg/dL] increase in FPG levels. Comparing with the low FPG level (under 86 mg/dL), every 1 μg/m³ increase in PM_2.5 was associated with a 10.20% (95% CI: 1.60%, 19.80%) increase in the odds of impaired fasting glucose (IFG) (100-125 mg/dL). Stratified analyses indicated greater effects on participants with hypertension [odds ratio (OR) = 1.30, 95% CI: 1.09, 1.57] and those had higher physical activities (OR = 1.36, 95% CI: 1.09, 1.57). Adolescents' sex, obesity status and different cutoff points of FPG did not modify the association between the exposure to PM_2.5 and FPG levels.

CONCLUSION

Long-term exposure to PM_2.5 was associated with increased FPG levels in Indonesian non-diabetic adolescents.

Association Between Metabolic and Hormonal Derangements and Professional Exposure to Urban Pollution in a High Intensity Traffic Area

Rationale: Studies suggest a relation between exposure to air particulate matter (PM)_2.5 pollution and greater cardiovascular morbidity, as well as increased risk for obesity and diabetes. We aimed to identify association(s) between nutritional and metabolic status and exposure to environmental pollution in a cohort of policemen exposed to high levels of air pollution. Methods: We considered adult municipal policemen, working in an urban area at high-traffic density with documented high levels of air PM_2.5 (exposed group) compared to non-exposed policemen. Clinical characteristics, including the presence/absence of metabolic syndrome, were recorded, and serum biomarkers, including adiponectin, leptin, and ghrelin, were assessed. Results: One hundred ninety-nine participants were enrolled, 100 in the exposed group and 99 in the non-exposed group. Metabolic syndrome was documented in 32% of exposed group and in 52.5% of non-exposed group (P = 0.008). In the exposed group, we found a positive correlation between body mass index and serum leptin as well as in the non-exposed group (P < 0.0001). Within the exposed group, subjects with metabolic syndrome showed lower serum adiponectin (P < 0.0001) and higher leptin (P = 0.002) levels with respect to those without metabolic syndrome, whereas in the non-exposed group, subjects with metabolic syndrome showed only higher leptin levels when compared to those without metabolic syndrome (P = 0.01). Among the participants with metabolic syndrome, we found lower adiponectin levels in those of the exposed group with respect to the non-exposed ones (P = 0.007). When comparing the exposed and non-exposed groups, after stratifying participants for Homeostatic Model Assessment for Insulin Resistance >2.5, we found lower adiponectin levels in those of the exposed group with respect to the non-exposed ones (P = 0.038). Conclusions: Exposure to air PM pollution was associated with lower levels of adiponectin in adult males with metabolic syndrome.

Association of Prenatal and Perinatal Exposures to Particulate Matter With Changes in Hemoglobin A1c Levels in Children Aged 4 to 6 Years

IMPORTANCE

Environmental risk factors for childhood type 2 diabetes, an increasing global problem, are understudied. Air pollution exposure has been reported to be a risk factor for this condition.

OBJECTIVE

To examine the association between prenatal and perinatal exposures to fine particulate matter with a diameter less than 2.5 μm (PM2.5) and changes in hemoglobin A1c (HbA1c), a measure of glycated hemoglobin and marker of glucose dysregulation, in children aged 4 to 7 years.

DESIGN, SETTING, AND PARTICIPANTS

The Programming Research in Obesity, Growth, Environment, and Social Stressors (PROGRESS) study, a birth cohort study conducted in Mexico City, Mexico, recruited pregnant women from July 3, 2007, to February 21, 2011, through public health maternity clinics. The present analysis includes 365 mother-child pairs followed up until the child was approximately 7 years of age. This study included data from only study visits at approximately 4 to 5 years (visit 1) and 6 to 7 years (visit 2) post partum because HbA1c levels were not measured in earlier visits. The data were analyzed from March 11, 2018, to May 3, 2019.

EXPOSURES

Daily PM2.5 exposure estimates at participants' home addresses from 4 weeks prior to mothers' date of last menstrual period (LMP), a marker of the beginning of pregnancy, to 12 weeks after the due date. Exposure was estimated from satellite measurements and calibrated against ground PM2.5 measurements, land use, and meteorological variables.

MAIN OUTCOMES AND MEASURES

Outcomes included HbA1c levels at 4 to 5 years and 6 to 7 years of age, and the change in the level from the former age group to the latter.

RESULTS

The sample included 365 children, of whom 184 (50.4%) were girls. The mean (range) age of the children was 4.8 (4.0-6.4) years at visit 1, and 6.7 (6.0-9.7) years at visit 2. At the time of delivery, the mean (range) age of the mothers was 27.7 (18.3-44.4) years, with a mean (range) prepregnancy body mass index of 26.4 (18.5-43.5). The mean (SD) prenatal PM2.5 exposure (22.4 μg/m3 [2.7 μg/m3]) was associated with an annual increase in HbA1c levels of 0.25% (95% CI, 0.004%-0.50%) from age 4 to 5 years to 6 to 7 years compared with exposure at 12 μg/m3, the national regulatory standard in Mexico. Sex-specific effect estimates were statistically significant for girls (β = 0.21%; 95% CI, 0.10% to 0.32%) but not for boys (β = 0.31%; 95% CI, -0.09% to 0.72%). The statistically significant windows of exposure were from week 28 to 50.6 after the mother's LMP for the overall cohort and from week 11 to the end of the study period for girls. Lower HbA1c levels were observed at age 4 to 5 years in girls (β = -0.72%; 95% CI, -1.31% to -0.13%, exposure window from week 16 to 37.3) and boys (β = -0.98%; 95% CI, -1.70% to -0.26%, exposure window from the beginning of the study period to week 32.7), but no significant association was found in the overall cohort (β = -0.13%; 95% CI, -1.27% to 1.01%). There was no significant association between PM2.5 exposure and HbA1c level at age 6 to 7 years in any group.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that prenatal and perinatal exposures to PM2.5 are associated with changes in HbA1c, which are indicative of glucose dysregulation, in early childhood. Further research is needed because this finding may represent a risk factor for childhood or adolescent diabetes.

Associations of air pollution, obesity and cardiometabolic health in young adults: The Meta-AIR study

OBJECTIVE

Growing evidence indicates exposure to air pollution contributes to obesity and cardiometabolic disease risk in children and adults, however studies are lacking in young adulthood, an important transitional period in the life course. The aim of this study was to examine the associations of short- and long-term regional ambient and near-roadway air pollution (NRAP) exposures on adiposity and cardiometabolic health in young adults aged 17-22 years.

METHODS

From 2014 to 2018, a subset of participants (n = 158) were recruited from the Children's Health Study to participate in the Meta-AIR (Metabolic and Asthma Incidence Research) study to assess obesity (body composition and abdominal adiposity) and cardiometabolic health (fasting glucose, fasting insulin and lipid profiles) measures. Prior 1-month and 1-year average air pollution exposures were calculated from residential addresses. This included nitrogen dioxide (NO₂), ozone (O₃), particulate matter with aerodynamic diameter < 10 μm (PM₁₀), particulate matter with aerodynamic diameter < 2.5 μm (PM_2.5) and NRAP (freeway, non-freeway, and total nitrogen oxides (NO_x)) exposures. Linear regression models examined associations of prior 1-month (short-term) and 1-year (long-term) air pollution exposures on obesity and cardiometabolic factors adjusting for covariates and past childhood air pollution exposures.

RESULTS

In the Meta-AIR study, we conducted a comprehensive analysis with short- and long-term regional ambient and NRAP exposures (in both single- and multi-pollutant models) and obesity- and cardiometabolic-related outcomes and found associations with a few outcomes. A 1 standard deviation (SD) change in long-term NO₂ exposure was associated with a 11.3 mg/dL higher level of total cholesterol (p = 0.04) and 9.4 mg/dL higher level of low-density lipoproteins (LDL)-cholesterol (p = 0.04). Amongst obese participants, associations between long-term NO₂ and total cholesterol and LDL-cholesterol were 4.5 and 9 times larger than the associations in non-obese participants (p_interaction = 0.008 and 0.03, respectively). Additionally, we observed a statistically significant association with increased short-term O₃ exposure and higher triglyceride and very-low-density lipoprotein (VLDL) cholesterol levels (p = 0.04), lower high-density lipoprotein (HDL) cholesterol levels (p = 0.03), and higher hepatic fat levels (p = 0.02). Amongst glucose-related factors, long-term PM_2.5 exposure was associated with higher levels of insulin area under the curve (p = 0.03). There were no other statistically significant associations with short- or long-term air pollutants and BMI, other measures of adiposity, and cardiometabolic outcomes.

CONCLUSION

Higher exposure to regional air pollutants, namely prior 1-year average NO₂, was associated with higher fasting serum lipid measures. These associations were more pronounced in obese participants, suggesting obesity may exacerbate the effects of air pollution exposure on lipid levels in young adults. This study did not find any other associations between short- and long-term ambient and NRAP exposures across a range of other obesity and cardiometabolic indicators. Further studies in young adults are warranted as our study suggests potential deleterious associations of both short- and long-term air pollution exposures and lipid metabolism.

Particulate matter air pollution and blood glucose in children and adolescents: A cross-sectional study in China

BACKGROUND

The health effects of particulate matter (PM) air pollution on glucose metabolism have been rarely examined in children and adolescents.

OBJECTIVE

We aimed to investigate the associations between long-term PM exposure and blood glucose and prevalence of impaired fasting glucose in a large population of Chinese children and adolescents.

METHODS

In 2013, a total of 11,814 children and adolescents aged 7 to 18 years were recruited from seven provinces/municipalities in China. Fasting blood sample was taken for the measurement of blood glucose. Satellite-based spatial-temporal models were used to estimate exposure to ambient submicrometer particles (PM₁), fine particles (PM_2.5) and thoracic particles (PM₁₀). Cross-sectional analyses were performed using mixed-effects multivariable linear and logistic regression models.

RESULTS

After adjustment for a range of covariates, every 10 μg/m³ increment in PM₁, PM_2.5 and PM₁₀ concentrations was associated with 0.160 [95% confidence interval (CI): 0.039, 0.280], 0.150 (95% CI: 0.044, 0.256) and 0.079 (95% CI: -0.009, 0.167) mmol/L higher blood glucose levels, respectively. PM exposure was also associated with higher prevalence of impaired fasting glucose, but the associations did not reach statistical significance [odds ratio per 10 μg/m³ increment in PM₁, PM_2.5 and PM₁₀: 1.30 (95% CI: 0.86,1.96), 1.20 (95% CI: 0.85,1.69) and 1.08 (95% CI: 0.83,1.41)].

CONCLUSIONS

We found that long-term exposure to PM air pollution was associated with increased levels of blood glucose in children and adolescents. The associations were more evident for PM₁ and PM_2.5.

Air Pollution as a Cause of Obesity: Micro-Level Evidence from Chinese Cities

Chinese air pollution is obviously increasing, and the government makes efforts to strengthen air pollution treatment. Although adverse health effects gradually emerge, research determining individual vulnerability is limited. This study estimated the relationship between air pollution and obesity. Individual information of 13,414 respondents from 125 cities is used in the analysis. This study employs ordinary least squares (OLS) and multinomial logit model (m-logit) to estimate the impact of air pollution on obesity. We choose different air pollution and Body Mass Index (BMI) indicators for estimation. Empirical results show Air Quality Index (AQI) is significantly positively associated with the BMI score. As AQI adds one unit, the BMI score increases 0.031 (SE = 0.002; p < 0.001). The influence coefficients of particle size smaller than 2.5 μm (PM_2.5), particle size smaller than 10 μm (PM₁₀), carbon monoxide (CO), nitrogen dioxide (NO₂), ozone (O₃), and sulfur dioxide (SO₂) to the BMI score are 0.034 (SE = 0.002; p < 0.001), 0.023 (SE = 0.001; p < 0.001), 0.52 (SE = 0.095; p < 0.001), 0.045 (SE = 0.004; p < 0.001), 0.021 (SE = 0.002; p < 0.001), 0.008 (SE = 0.003; p = 0.015), respectively. Generally, air pollution has an adverse effect on body weight. CO is the most influential pollutant, and female, middle-aged, and low-education populations are more severely affected. The results confirm that the adverse health effects of air pollution should be considered when making the air pollution policies. Findings also provide justification for health interventions, especially for people with obesity.

Lack of association between particulate air pollution and blood glucose levels and diabetic status in peri-urban India

BACKGROUND

Limited evidence exists on the effect of particulate air pollution on blood glucose levels. We evaluated the associations of residential and personal levels of fine particulate matter (PM_2.5) and black carbon (BC) with blood glucose and diabetic status among residents of 28 peri-urban villages in South India.

METHODS

We used cross-sectional data from 5065 adults (≥18 years, 54% men) included in the Andhra Pradesh Children and Parents Study. Fasting plasma glucose was measured once in 2010-2012 and prevalent prediabetes and diabetes were defined following the American Diabetes Association criteria. We estimated annual ambient PM_2.5 and BC levels at residence using land-use regression models and annual personal exposure to PM_2.5 and BC using prediction models based on direct measurements from a subsample of 402 participants. We used linear and logistic nested mixed-effect models to assess the association between exposure metrics and health outcomes. For personal exposures, we stratified analyses by sex.

RESULTS

Mean (SD) residential PM_2.5 and BC were 32.9 (2.6) μg/m³ and 2.5 (2.6) μg/m³, respectively; personal exposures to PM_2.5 and BC were 54.5 (11.5) μg/m³ and 5.8 (2.5) μg/m³, respectively. Average (SD) fasting blood glucose was 5.3 (1.3) mmol/l, 16% of participants had prediabetes, and 5.5% had diabetes. Residential PM_2.5 and BC were not associated with higher blood glucose levels. Personal PM_2.5 (20 μg/m³ increase) and BC (1 μg/m³ increase) were negatively associated with blood glucose levels in women (PM_2.5: -1.93, 95%CI: -3.12, -0.73; BC: -0.63, 95%CI: -0.90, -0.37). In men, associations were negative for personal PM_2.5 (-1.99, 95%CI: -3.56, -0.39) and positive for personal BC (0.49, 95%CI: -0.44, 1.43). We observed no evidence of associations between any exposure and prevalence of prediabetes/diabetes.

CONCLUSIONS

Our results do not provide evidence that residential exposures to PM_2.5 or BC are associated with blood glucose or prevalence of prediabetes/diabetes in this population. Associations with personal exposure may have been affected by unmeasured confounding, highlighting a challenge in using personal exposure estimates in air pollution epidemiology. These associations should be further examined in longitudinal studies.

Effects of ambient particulate matter on fasting blood glucose among primary school children in Guangzhou, China

BACKGROUND

Exposure to ambient particulate matter (PM) has been linked with diabetes and elevated blood glucose in adults. However, there are few reports on the effects of PM on fasting blood glucose (FBG) among children.

OBJECTIVES

The study aimed to assess the associations between medium-term exposure of ambient particles with diameters ≤2.5 μm (PM_2.5), and ≤10 μm (PM₁₀) and FBG in a general population of children, and also to explore the modifying effects of diet.

METHODS

In this cross-sectional study, we enrolled 4234 children (aged 6-13 years) residing in Guangzhou, China, in 2017. Individual PM_2.5 and PM₁₀ exposures during the 186-day period before each physical examination were retrospectively estimated by an inverse distance weighting interpolation and time-weighted approach according to their home address, school address, and activity patterns. Linear mixed effect models were used to examine the relationships between PM_2.5 and PM₁₀ with FBG after adjusting for covariates.

RESULTS

We found that per 10 μg/m³ increase in PM_2.5 and PM₁₀ levels during the 186-day period were associated with 2.3% (95% CI: 1.0%, 3.8%) higher FBG and 0.9% (95% CI: 0.5%, 1.4%) higher FBG, respectively. Stronger effect estimates were observed among subgroups of children with a family history of diabetes, and higher intake of sugar-sweetened beverages (SSBs). Also, we found significant interactions between PM_2.5 concentration and family history of diabetes and SSBs intake on FBG.

CONCLUSIONS

Medium-term exposure to ambient PM_2.5 and PM₁₀ were associated with higher FBG levels in children, and that higher SSBs intake might modify these associations.

Near-roadway air pollution exposure and altered fatty acid oxidation among adolescents and young adults - The interplay with obesity

BACKGROUND

Air pollution exposure has been shown to increase the risk of obesity and metabolic dysfunction in animal models and human studies. However, the metabolic pathways altered by air pollution exposure are unclear, especially in adolescents and young adults who are at a critical period in the development of cardio-metabolic diseases.

OBJECTIVES

The aim of this study was to examine the associations between air pollution exposure and indices of fatty acid and amino acid metabolism.

METHODS

A total of 173 young adults (18-23 years) from eight Children's Health Study (CHS) Southern California communities were examined from 2014 to 2018. Near-roadway air pollution (NRAP) exposure (freeway and non-freeway) and regional air pollution exposure (nitrogen dioxide, ozone and particulate matter) during one year before the study visit were estimated based on participants' residential addresses. Serum concentrations of 64 targeted metabolites including amino acids, acylcarnitines, non-esterified fatty acid (NEFA) and glycerol were measured in fasting serum samples. Principal component analysis of metabolites was performed to identify metabolite clusters that represent key metabolic pathways. Mixed effects models were used to analyze the associations of air pollution exposure with metabolomic principal component (PC) scores and individual metabolite concentrations adjusting for potential confounders.

RESULTS

Higher lagged one-year averaged non-freeway NRAP exposure was associated with higher concentrations of NEFA oxidation byproducts and higher NEFA-related PC score (all p's ≤ 0.038). The effect sizes were larger among obese individuals (interaction p = 0.047). Among females, higher freeway NRAP exposure was also associated with a higher NEFA-related PC score (p = 0.042). Among all participants, higher freeway NRAP exposure was associated with a lower PC score for lower concentrations of short- and median-chain acylcarnitines (p = 0.044).

CONCLUSIONS

Results of this study indicate that NRAP exposure is associated with altered fatty acid metabolism, which could contribute to the metabolic perturbation in obese youth.