Maternal exposure to air pollution and type 1 diabetes--Accounting for genetic factors

Fecal microbiota transplantation in autoimmune diseases - An extensive paper on a pathogenetic therapy

The role of infections in the pathogenesis of autoimmune diseases has long been recognized and reported. In addition to infectious agents, the internal composition of the "friendly" living bacteria, (microbiome) and its correlation to immune balance and dysregulation have drawn the attention of researchers for decades. Nevertheless, only recently, scientific papers regarding the potential role of transferring microbiome from healthy donor subjects to patients with autoimmune diseases has been proposed. Fecal microbiota transplantation or FMT, carries the logic of transferring microorganisms responsible for immune balance from healthy donors to individuals with immune dysregulation or more accurately for our paper, autoimmune diseases. Viewing the microbiome as a pathogenetic player allows us to consider FMT as a pathogenetic-based treatment. Promising results alongside improved outcomes have been demonstrated in patients with different autoimmune diseases following FMT. Therefore, in our current extensive review, we aimed to highlight the implication of FMT in various autoimmune diseases, such as inflammatory bowel disease, autoimmune thyroid and liver diseases, systemic lupus erythematosus, and type 1 diabetes mellitus, among others. Presenting all the aspects of FMT in more than 12 autoimmune diseases in one paper, to the best of our knowledge, is the first time presented in medical literature. Viewing FMT as such could contribute to better understanding and newer application of the model in the therapy of autoimmune diseases, indeed.

Towards a better understanding of diabetes mellitus using organoid models

Our understanding of diabetes mellitus has benefited from a combination of clinical investigations and work in model organisms and cell lines. Organoid models for a wide range of tissues are emerging as an additional tool enabling the study of diabetes mellitus. The applications for organoid models include studying human pancreatic cell development, pancreatic physiology, the response of target organs to pancreatic hormones and how glucose toxicity can affect tissues such as the blood vessels, retina, kidney and nerves. Organoids can be derived from human tissue cells or pluripotent stem cells and enable the production of human cell assemblies mimicking human organs. Many organ mimics relevant to diabetes mellitus are already available, but only a few relevant studies have been performed. We discuss the models that have been developed for the pancreas, liver, kidney, nerves and vasculature, how they complement other models, and their limitations. In addition, as diabetes mellitus is a multi-organ disease, we highlight how a merger between the organoid and bioengineering fields will provide integrative models.

Changes in the Global Epidemiology of Type 1 Diabetes in an Evolving Landscape of Environmental Factors: Causes, Challenges, and Opportunities

The worldwide incidence of type 1 diabetes mellitus (T1DM) has increased in recent decades. The reasons behind this phenomenon are not yet fully understood. Early life infections, prenatal and perinatal factors, and diet composition have been associated with the triggering of autoimmunity and the risk of presentation of T1DM. However, the rapid increase in new cases of the disease raises the hypothesis that lifestyle factors, which have traditionally been associated with type 2 diabetes, such as obesity and unhealthy eating patterns could also play a role in the genesis of autoimmune diabetes. This article aims to highlight the changing epidemiology of T1DM and the importance of properly recognizing the environmental factors behind it, as well as the connections with the pathogenesis of the disorder and the need to prevent or delay T1DM and its long-term complications.

Fecal microbiota transplantation treatment of autoimmune-mediated type 1 diabetes: A systematic review

There is a strong link between fecal microbiota and the development of type 1 diabetes. As an emerging therapeutic modality, fecal microbiota transplantation has been shown to be safe and effective in the treatment of many intestinal and extraintestinal diseases. Various studies have found that fecal microbiota transplantation can treat diseases by correcting patients' immune disorders. Besides, many studies have found that fecal microbiota transplantation can improve glycemic control and insulin resistance in diabetic patients. Therefore, this paper reviews the mechanism of action of fecal microbiota transplantation on autoimmune-mediated T1DM and the current research progress, feasibility, and issues that need to be addressed in the future development of fecal microbiota transplantation in the treatment of autoimmune-mediated T1DM.

Air Pollution, Oxidative Stress, and the Risk of Development of Type 1 Diabetes

Despite multiple studies focusing on environmental factors conducive to the development of type 1 diabetes mellitus (T1DM), knowledge about the involvement of long-term exposure to air pollution seems insufficient. The main focus of epidemiological studies is placed on the relationship between exposure to various concentrations of particulate matter (PM): PM1, PM2.5, PM10, and sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (O3), versus the risk of T1DM development. Although the specific molecular mechanism(s) behind the link between increased air pollution exposure and a higher risk of diabetes and metabolic dysfunction is yet unknown, available data indicate air pollution-induced inflammation and oxidative stress as a significant pathway. The purpose of this paper is to assess recent research examining the association between inhalation exposure to PM and associated metals and the increasing rates of T1DM worldwide. The development of modern and more adequate methods for air quality monitoring is also introduced. A particular emphasis on microsensors, mobile and autonomous measuring platforms, satellites, and innovative approaches of IoT, 5G connections, and Block chain technologies are also presented. Reputable databases, including PubMed, Scopus, and Web of Science, were used to search for relevant literature. Eligibility criteria involved recent publication years, particularly publications within the last five years (except for papers presenting a certain novelty or mechanism for the first time). Population, toxicological and epidemiological studies that focused particularly on fine and ultra-fine PM and associated ambient metals, were preferred, as well as full-text publications.

Impact of land use and food environment on risk of type 2 diabetes: A national study of veterans, 2008-2018

BACKGROUND

Large-scale longitudinal studies evaluating influences of the built environment on risk for type 2 diabetes (T2D) are scarce, and findings have been inconsistent.

OBJECTIVE

To evaluate whether land use environment (LUE), a proxy of neighborhood walkability, is associated with T2D risk across different US community types, and to assess whether the association is modified by food environment.

METHODS

The Veteran's Administration Diabetes Risk (VADR) study is a retrospective cohort of diabetes-free US veteran patients enrolled in VA primary care facilities nationwide from January 1, 2008, to December 31, 2016, and followed longitudinally through December 31, 2018. A total of 4,096,629 patients had baseline addresses available in electronic health records that were geocoded and assigned a census tract-level LUE score. LUE scores were divided into quartiles, where a higher score indicated higher neighborhood walkability levels. New diagnoses for T2D were identified using a published computable phenotype. Adjusted time-to-event analyses using piecewise exponential models were fit within four strata of community types (higher-density urban, lower-density urban, suburban/small town, and rural). We also evaluated effect modification by tract-level food environment measures within each stratum.

RESULTS

In adjusted analyses, higher LUE had a protective effect on T2D risk in rural and suburban/small town communities (linear quartile trend test p-value <0.001). However, in lower density urban communities, higher LUE increased T2D risk (linear quartile trend test p-value <0.001) and no association was found in higher density urban communities (linear quartile trend test p-value = 0.317). Particularly strong protective effects were observed for veterans living in suburban/small towns with more supermarkets and more walkable spaces (p-interaction = 0.001).

CONCLUSION

Among veterans, LUE may influence T2D risk, particularly in rural and suburban communities. Food environment may modify the association between LUE and T2D.

Association of long-term environmental exposures in pregnancy and early life with islet autoimmunity development in children in Bavaria, Germany

OBJECTIVE

Incidence of early-onset type 1 diabetes (T1D) has been increasing worldwide. Only few studies examined the relationship between geographical environmental variation and T1D incidence or its presymptomatic stage of islet autoimmunity. Our study aimed to investigate the effect of long-term environmental exposures during pregnancy and early life on childhood islet autoimmunity.

RESEARCH DESIGN AND METHODS

We used data from the Fr1da cohort study which screened children aged 1.75-5.99 years for multiple islet autoantibodies in Bavaria, Germany between 2015 and 2019. We included 85,251 children with valid residential information. Daily averages for particulate matter with a diameter <2.5 μm, nitrogen dioxide, ozone, air temperature, and greenness were averaged for each zip-code or directly assigned to the addresses. The exposure windows included pregnancy, the first year and the first two years of life. Generalized additive models adjusting for individual and socioeconomic variables were used to investigate associations between environmental exposures and islet autoimmunity development.

RESULTS

Islet autoimmunity was diagnosed in 272 children. Colder air temperature during pregnancy was associated with developing islet autoimmunity at the address (per 2.2 °C decrease, Odds ratio (OR): 1.49; 95% Confidence interval (CI): 1.21-1.83) and zip-code level (per 2.4 °C decrease, OR: 1.31; 95% CI: 1.08-1.59). Using the addresses, significant associations were also observed during the first years of life.

CONCLUSION

In this study, children's residential exposure to lower levels of air temperature during pregnancy and early life increased the risk of islet autoimmunity before the age of six.

Burden of type 1 diabetes mellitus in the North Africa and Middle East Region, 1990-2019; findings from the global burden of disease study

AIMS

We aimed to report the burden of type 1 diabetes mellitus (T1DM) in the North Africa and Middle East region and its 21 countries from 1990 to 2019.

METHODS

Information related to incidence, prevalence, mortality, disability-adjusted life-years (DALYs), and years lived with disability (YLDs) of T1DM was acquired from the 2019 Global Burden of Disease study. The burden was estimated by sex, age groups, and socio-demographic index (SDI) in 21 countries.

RESULTS

Over the past 30 years, regional incidence, prevalence, mortality, and DALYs of T1DM increase by 188.7%, 304.8%, 43.7%, and 71.6%, respectively. While the age-standardized incidence and prevalence rates increased by 84% and 91%, the mortality and DALYs rates decreased by 34% and 13%. During these years, the contribution of YLDs to total DALYs increased considerably (from 17% to 42%). The highest increase in the incidence and prevalence rates occurred in high SDI countries. Moreover, the Mortality to Incidence Ratio (MIR) decreased in the region countries.

CONCLUSIONS

Despite progress made in diabetes care, there is a persistently increasing burden of T1DM in the region countries. This indicates that T1DM is still one of the major health challenges in the region countries, especially in high SDI Arab countries.

Prenatal exposure to traffic-related air pollution and glucose homeostasis: A cross-sectional study

Air pollution exposure has been linked with glucose dysregulation in pregnant women; however, evidence on these associations with fetal glucose homeostasis is unclear yet. We therefore aimed to evaluate the association of prenatal exposure to particulate matter (PM) and traffic indicators with fetal glucose homeostasis in cord blood samples. A total of 169 mother-infant pairs recruited from Mobini hospital of Sabzevar, Iran, were included in this cross-sectional study. Maternal exposure to PMs was estimated using land use regression models. Moreover, traffic indicators (i.e., total street length in 100, 300 and 500 m buffers and distance from residential home to the nearest major roads) were calculated based on the street map of Sabzevar. Cord blood glucose and insulin concentrations, HOMA-ꞵ, HOMA-S and HOMA-IR were used as glucose homeostasis markers. Higher maternal exposure to PM_2.5 and PM₁₀ were associated with higher cord blood glucose and insulin concentrations and HOMA-IR. Moreover, total streets length in 300 m buffer was positively associated with cord blood glucose and insulin concentrations and HOMA-IR. An increase in distance to major roads was associated with higher HOMA-ꞵ and HOMA-S and lower cord blood glucose and insulin concentrations as well as HOMA-IR. Overall, we found prenatal exposure to PMs and traffic indicators was associated with a higher risk of glucose homeostasis dysregulation in the fetus.

Correlation between total air pollutant emissions and incidence of type 1 diabetes in the Russian Federation

BACKGROUND

Exposure to air pollution (gaseous pollutants and/or particulate matter) has been associated with the incidence, prevalence, and mortality of type 1 diabetes (T1D).

PURPOSE

To examine the quantitative relationship between air pollutant emissions and the incidence of T1D.

METHODS

We examined the association between the incidence of T1D and type 2 diabetes (T2D) in 2017 as well as that of T1D in patients younger than 15 years in 2016 with "emissions of air-polluting substances from stationary and mobile sources by regions of the Russian Federation in 2016" as reported by the Federal Diabetes Register of Russia downloaded from the Russian government website (http://www.mnr.gov.ru/docs/gosudarstvennye_doklady/o_sostoyanii_i_ob_okhrane_okruzhayushchey_sredy_rossiyskoy_federatsii/).

RESULTS

The incidence of T1D across all ages in each region of the Russian Federation correlated with the total air pollutants emitted in the region each year (r=0.278, P=0.013). The incidence of T2D was also correlated with the amount of air pollutants (r=0.234, P=0.037) and the incidence of T1D (r=0.600, P<0.001) in each country. Similarly, the incidence of T1D in patients younger than 15 years correlated with the total air pollutants emitted each year in each region (r=0.300, P=0.011).

CONCLUSION

The quantitative relationship between the total air pollutants emitted and the incidence of T1D and T2D in the Russian Federation suggests that air pollution contributes to the development of T1D and T2D.

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.

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.

Environmental cadmium exposure during pregnancy causes diabetes-like phenotypes in mouse offspring: Association with oxidative stress in the fetal liver

Cadmium (Cd), a noxious heavy metal, is widespread in the living environment. Gestational exposure to Cd at environmental dose has been shown to cause fetal growth restriction (FGR). However, the long-term effects and the mechanisms underlying environmental Cd exposure on glucose metabolism in offspring remain unclear. Here, we established a murine model to study the impacts of gestational exposure to environmental Cd on glucose metabolism at different life stages of offspring. Results demonstrated that the offspring mice developed hyperglycemia in puberty and impaired glucose tolerance in adulthood following maternal Cd exposure during gestation. Further mechanistic investigation showed that Cd exposure upregulated the expression of key proteins in hepatic gluconeogenesis, including p-CREB, PGC-1α and G6PC, in pubertal and adult offspring. In addition, we demonstrated that Cd exposure during pregnancy markedly elevated the level of oxidative stress-related proteins, including NOX2, NOX4 and HO-1, in the fetal liver. The effects of gestational exposure to N-acetylcysteine (NAC), a free-radical scavenging antioxidant, presented that NAC supplementation alleviated hepatic oxidative stress in fetuses, and thereby reversed hyperglycemia and glucose intolerance in mouse offspring. Collectively, our data suggested that gestational exposure to environmental Cd caused diabetes-like phenotypes via enhancing hepatic gluconeogenesis, which is associated with oxidative stress in fetal livers. This work provides new insights into the protective effects of antioxidants on fetal-originated diabetes triggered by environmental toxicants.

Inappropriately sweet: Environmental endocrine-disrupting chemicals and the diabetes pandemic

Afflicting hundreds of millions of individuals globally, diabetes mellitus is a chronic disorder of energy metabolism characterized by hyperglycemia and other metabolic derangements that result in significant individual morbidity and mortality as well as substantial healthcare costs. Importantly, the impact of diabetes in the United States is not uniform across the population; rather, communities of color and those with low income are disproportionately affected. While excessive caloric intake, physical inactivity, and genetic susceptibility are undoubted contributors to diabetes risk, these factors alone fail to fully explain the rapid global rise in diabetes rates. Recently, environmental contaminants acting as endocrine-disrupting chemicals (EDCs) have been implicated in the pathogenesis of diabetes. Indeed, burgeoning data from cell-based, animal, population, and even clinical studies now indicate that a variety of structurally distinct EDCs of both natural and synthetic origin have the capacity to alter insulin secretion and action as well as global glucose homeostasis. This chapter reviews the evidence linking EDCs to diabetes risk across this spectrum of evidence. It is hoped that improving our understanding of the environmental drivers of diabetes development will illuminate novel individual-level and policy interventions to mitigate the impact of this devastating condition on vulnerable communities and the population at large.

Epigenetic Changes Induced by Maternal Factors during Fetal Life: Implication for Type 1 Diabetes

Organ-specific autoimmune diseases, such as type 1 diabetes, are believed to result from T-cell-mediated damage of the target tissue. The immune-mediated tissue injury, in turn, is known to depend on complex interactions between genetic and environmental factors. Nevertheless, the mechanisms whereby environmental factors contribute to the pathogenesis of autoimmune diseases remain elusive and represent a major untapped target to develop novel strategies for disease prevention. Given the impact of the early environment on the developing immune system, epigenetic changes induced by maternal factors during fetal life have been linked to a likelihood of developing an autoimmune disease later in life. In humans, DNA methylation is the epigenetic mechanism most extensively investigated. This review provides an overview of the critical role of DNA methylation changes induced by prenatal maternal conditions contributing to the increased risk of immune-mediated diseases on the offspring, with a particular focus on T1D. A deeper understanding of epigenetic alterations induced by environmental stressors during fetal life may be pivotal for developing targeted prevention strategies of type 1 diabetes by modifying the maternal environment.

Relationships between emissions of toxic airborne molecules and type 1 diabetes incidence in children: An ecologic study

BACKGROUND

Type 1 diabetes originates from gene-environment interactions, with increasing incidence over time.

AIM

To identify correlates of childhood type 1 diabetes in European countries using an ecological approach. Several environmental variables potentially influencing the onset of type 1 diabetes have been previously evaluated. However, the relationships between epidemiologic data and exposure to toxic airborne molecules are scarcely studied.

METHODS

We employed an ecological model to explore, in a wide time period (1990-2018), associations between type 1 diabetes incidence in 19 European countries (systematic literature review) and the nationwide production of five widely diffused air pollutants: particulate matter < 10 μm (PM10), nitrogen oxides (NO), non-methane volatile organic compounds (VOCs), sulphur oxide (SO₂), and ammonia.

RESULTS

Data confirm a raising incidence of type 1 diabetes in 18 out of 19 explored countries. The average difference (last vs first report, all countries) was +6.9 × 100000/year, with values ranging from -1.4 (Germany) to +16.6 (Sweden) per 100000/year. Although the overall production of pollutants decreased progressively from 1990 to 2018, type 1 diabetes incidence was positively associated with the nationwide emissions of PM10, VOCs, and NO but not with those of SO2 and ammonia. Type 1 diabetes incidence was significantly higher in countries with high emissions than in those with low emissions of PM10 (27.5 ± 2.4 vs 14.6 ± 2.4 × 100000 residents, respectively), VOCs (24.5 ± 4.4 vs 13.2 ± 1.7 × 100000 residents, respectively), and NO (26.6 ± 3 vs 13.4 ± 2.4 × 100000 residents, respectively), but not of SO₂ or ammonia.

CONCLUSION

Evidence justify further studies to explore better links between long-term air quality and type 1 diabetes onset at the individual level, which should include exposures during pregnancy. In this respect, type 1 diabetes could be, at least in part, a preventable condition. Thus, primary prevention policies acting through a marked abatement of pollutant emissions might attenuate future type 1 diabetes incidence throughout Europe.

Why is the Incidence of Type 1 Diabetes Increasing?

Type 1 diabetes is a condition that can lead to serious long-term complications and can have significant psychological and quality of life implications. Its incidence is increasing in all parts of the world, but the reasons for this are incompletely understood. Genetic factors alone cannot explain such a rapid increase in incidence; therefore, environmental factors must be implicated. Lifestyle factors have been classically associated with type 2 diabetes. However, there are data implicating obesity and insulin resistance to type 1 diabetes as well (accelerator hypothesis). Cholesterol has also been shown to be correlated with the incidence of type 1 diabetes; this may be mediated by immunomodulatory effects of cholesterol. There is considerable interest in early life factors, including maternal diet, mode of delivery, infant feeding, childhood diet, microbial exposure (hygiene hypothesis), and use of anti-microbials in early childhood. Distance from the sea has recently been shown to be negatively correlated with the incidence of type 1 diabetes. This may contribute to the increasing incidence of type 1 diabetes since people are increasingly living closer to the sea. Postulated mediating mechanisms include hours of sunshine (and possibly vitamin D levels), mean temperature, dietary habits, and pollution. Ozone, polychlorinated biphenyls, phthalates, trichloroethylene, dioxin, heavy metals, bisphenol, nitrates/nitrites, and mercury are amongst the chemicals which may increase the risk of type 1 diabetes. Another area of research concerns the role of the skin and gut microbiome. The microbiome is affected by many of the factors mentioned above, including the mode of delivery, infant feeding, exposure to microbes, antibiotic use, and dietary habits. Research on the reasons why the incidence of type 1 diabetes is increasing not only sheds light on its pathogenesis but also offers insights into ways we can prevent type 1 diabetes.

Birth during the moderate weather seasons is associated with early onset of type 1 diabetes in the Mediterranean area

AIM

To assess the association of seasonal and perinatal parameters with early age of type 1 diabetes (T1D) onset.

METHODS

A cross-sectional review of all medical records of T1D patients born between the years 1990 and 2005, and diagnosed before/by the age of 10 years, from 13 university-affiliated paediatric medical centres in Israel, was performed. Data included: gender, ethnicity, seasons of birth and disease onset, birth gestational age and weight, and autoimmune diseases of the probands and their first-degree family members. Statistical analysis included the Chi-square test or Mann-Whitney test, as appropriate and multivariate regression analysis.

RESULTS

Enrolled were 1571 T1D patients at a median age of T1D onset 6.9 years (IQR 4.4,8.4); 336 of them presented before 4 years of age. The median age of this group was 2.5 years (IQR 1.7,3.2), and of the 1235 patients who presented after 4 years of age, median presentation age was 7.5 years (IQR 6.1,8.8). Multivariate regression analysis demonstrated that a more recent birth year; OR = 1.06, 95% CI 1.02-1.1, P = 0.003, and birth during the moderate weather months (September, October, March, and April) were significantly associated with younger age at T1D onset; OR = 1.68, 95% CI 1.17-2.4, P = 0.005.

CONCLUSIONS

Our novel finding demonstrates the association between younger than 4 years old age at presentation and birth during moderate weather months. The results also support previous reports, that there is a slight increase in the annual incidence of T1D in the youngest age groups.

Particle concentrations, dispersion modelling and evaluation in southern Sweden

Health impact assessments of differential air pollution rely on epidemiologically established relationships between concentration levels where people are exposed and adverse health outcomes. To assess air pollution concentrations, land use regression is commonly used. However, an alternative tool is dispersion modelling, where a detailed inventory of pollution sources together with meteorological data drives calculations of compound dispersion. With this, both spatial and temporal variation can be assessed. In this study, we evaluated results of a Gaussian dispersion model applied to an emissions inventory for Scania, the southernmost county in Sweden. The dispersion considered was particulate matter of aerodynamic diameter < 10 µm (PM10), particulate matter of aerodynamic diameter < 2.5 µm (PM2.5) and black carbon (BC) during an 11-year period (2000–2011). Mean concentrations and 95th percentiles expressed in µg/m3 ranged from 10.1 to 12.6 and 16.6 to 20.7 for PM2.5 and from 14.0 to 18.8 and 22.6 to 27.0 for PM10, respectively. Seven monitoring stations were used for evaluation. Correlations (R2) ranged from 0.44 to 0.86 for PM2.5 (mean bias from − 9.0 to 0.1 µg/m3) and from 0.46 to 0.83 for PM10 (mean bias − 6.1 to 3.5 µg/m3). An evaluated database of PM and BC concentrations for Scania is now available for future exposure assessment projects. Calculations were based on a well-known dispersion model with detailed emission data as input. The evaluation showed correlation coefficients for PM in line with previous literature. The data on PM10, PM2.5 and BC concentrations will, therefore, be used in subsequent studies, epidemiological as well as health impact assessments.

Ambient air pollution and incidence of early-onset paediatric type 1 diabetes: A retrospective population-based cohort study

BACKGROUND

Studies have reported increasing incidence rates of paediatric diabetes, especially among those aged 0-5 years. Epidemiological evidence linking ambient air pollution to paediatric diabetes remains mixed.

OBJECTIVE

This study investigated the association between maternal and early-life exposures to common air pollutants (NO₂, PM_2.5, O₃, and oxidant capacity [Ox; the redox-weighted average of O₃ and NO₂]) and the incidence of paediatric diabetes in children up to 6 years of age.

METHODS

All registered singleton births in Ontario, Ca nada occurring between April 1st^, 2006 and March 31st^, 2012 were included through linkage from health administrative data. Monthly exposures to NO₂, PM_2.5, O₃, and O_x were estimated across trimesters, the entire pregnancy period and during childhood. Random effects Cox proportional hazards models were used to assess the relationships with paediatric diabetes incidence while controlling for important covariates. We also modelled the shape of concentration-response (CR) relationships.

RESULTS

There were 1094 children out of a cohort of 754,698 diagnosed with diabetes before the age of six. O₃ exposures during the first trimester of pregnancy were associated with paediatric diabetes incidence (hazard ratio (HR) per interquartile (IQR) increase = 2.00, 95% CI: 1.04-3.86). The CR relationship between O₃ during the first trimester and paediatric diabetes incidence appeared to have a risk threshold, in which there was little-to-no risk below 25 ppb of O₃, while above this level risk increased sigmoidally. No other associations were observed.

CONCLUSION

O₃ exposures during a critical period of development were associated with an increased risk of paediatric diabetes incidence.

Ambient air pollution and the risk of pediatric-onset inflammatory bowel disease: A population-based cohort study

BACKGROUND

High-income nations have the highest rates of inflammatory bowel disease (IBD). The incidence of pediatric-onset IBD is increasing faster than IBD diagnosed in older individuals. Previous epidemiological studies have shown that air pollution might be a risk factor for development of earlier-onset IBD, but results remain mixed.

OBJECTIVES

The objective of this study was to evaluate the associations between maternal and early-life exposures to nitrogen dioxide (NO₂), fine particulate matter (PM_2.5), ozone (O₃,) and oxidant capacity (O_x) and risk of pediatric-onset IBD diagnosis.

METHODS

We conducted a retrospective cohort study using linked population-based health administrative data. Singleton livebirths in Ontario, Canada between April 1st, 1991 and March 31st, 2014 were included. We investigated the association between weekly exposures during pregnancy and annual exposures from birth until the age of 18 years, and IBD diagnosed <18 years of age using Cox proportional hazards models. We reported hazard ratios (HR) and 95% confidence intervals (CI) for an associated increase in the interquartile range (IQR) of each pollutant. Models were mutually adjusted for exposures in both prenatal and postnatal periods, as well as for sex, rurality of residence at birth, maternal IBD, and neighborhood income.

RESULTS

2,218,789 newborns were included in this study, of whom 2491 developed IBD during follow-up. Increased associations with pediatric-onset IBD were noted for childhood exposure to O_x (HR 1.08, 95% CI 1.01-1.16). IBD development was also associated with O_x during the second trimester (HR 1.21, 95% CI 1.03-1.42), but not the overall pregnancy period (HR 1.12, 95% CI 0.79-1.59). There were no associations of IBD with exposure to NO₂, PM_2.5, or O₃.

DISCUSSION

Exposure to O_x during childhood was associated with IBD < 18 years. This suggests that air pollution may impact the developing child physiology in such a way that leads to early onset of IBD.

Endocrine Disrupting Chemicals and Type 1 Diabetes

Type 1 diabetes (T1D) is the most common chronic metabolic disease in children and adolescents. The etiology of T1D is not fully understood but it seems multifactorial. The genetic background determines the predisposition to develop T1D, while the autoimmune process against β-cells seems to be also determined by environmental triggers, such as endocrine disrupting chemicals (EDCs). Environmental EDCs may act throughout different temporal windows as single chemical agent or as chemical mixtures. They could affect the development and the function of the immune system or of the β-cells function, promoting autoimmunity and increasing the susceptibility to autoimmune attack. Human studies evaluating the potential role of exposure to EDCs on the pathogenesis of T1D are few and demonstrated contradictory results. The aim of this narrative review is to summarize experimental and epidemiological studies on the potential role of exposure to EDCs in the development of T1D. We highlight what we know by animals about EDCs’ effects on mechanisms leading to T1D development and progression. Studies evaluating the EDC levels in patients with T1D were also reported. Moreover, we discussed why further studies are needed and how they should be designed to better understand the causal mechanisms and the next prevention interventions.

Connecting Air Pollution Exposure to Socioeconomic Status: A Cross-Sectional Study on Environmental Injustice among Pregnant Women in Scania, Sweden

Environmental injustice, characterized by lower socioeconomic status (SES) persons being subjected to higher air pollution concentrations, was explored among pregnant women in Scania, Sweden. Understanding if the general reduction of air pollution recorded is enjoyed by all SES groups could illuminate existing inequalities and inform policy development. "Maternal Air Pollution in Southern Sweden", an epidemiological database, contains data for 48,777 pregnancies in Scanian hospital catchment areas and includes births from 1999-2009. SES predictors considered included education level, household disposable income, and birth country. A Gaussian dispersion model was used to model women's average NO_X and PM_2.5 exposure at home residence over the pregnancy period. Total concentrations were dichotomized into emission levels below/above respective Swedish Environmental Protection Agency (EPA) Clean Air objectives. The data were analyzed using binary logistic regression. A sensitivity analysis facilitated the investigation of associations' variation over time. Lower-SES women born outside Sweden were disproportionately exposed to higher pollutant concentrations. Odds of exposure to NO_X above Swedish EPA objectives reduced over time, especially for low-SES persons. Environmental injustice exists in Scania, but it lessened with declining overall air pollution levels, implying that continued air quality improvement could help protect vulnerable populations and further reduce environmental inequalities.

Prenatal exposure to air pollution as a potential risk factor for autism and ADHD

Genetic and environmental factors both contribute to the development of Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD). One suggested environmental risk factor for ASD and ADHD is air pollution, but knowledge of its effects, especially in low-exposure areas, are limited. Here, we investigate risks for ASD and ADHD associated with prenatal exposure to air pollution in an area with air pollution levels generally well below World Health Organization (WHO) air quality guidelines. We used an epidemiological database (MAPSS) consisting of virtually all (99%) children born between 1999 and 2009 (48,571 births) in the study area, in southern Sweden. MAPSS consists of data on modelled nitrogen oxide (NO_x) levels derived from a Gaussian dispersion model; maternal residency during pregnancy; perinatal factors collected from a regional birth registry; and socio-economic factors extracted from Statistics Sweden. All ASD and ADHD diagnoses in our data were undertaken at the Malmö and Lund Departments of Child and Adolescent Psychiatry, using standardized diagnostic instruments. We used logistic regression analyses to obtain estimates of the risk of developing ASD and ADHD associated with different air pollution levels, with adjustments for potential perinatal and socio-economic confounders. In this longitudinal cohort study, we found associations between air pollution exposure during the prenatal period and and the risk of developing ASD. For example, an adjusted Odds Ratio (OR) of 1.40 and its 95% Confidence Interval (CI) (95% CI: 1.02-1.93) were found when comparing the fourth with the first quartile of NO_x exposure. We did not find similar associations on the risk of developing ADHD. This study contributes to the growing evidence of a link between prenatal exposure to air pollution and autism spectrum disorders, suggesting that prenatal exposure even below current WHO air quality guidelines may increase the risk of autism spectrum disorders.

Inflammation and acute traffic-related air pollution exposures among a cohort of youth with type 1 diabetes

BACKGROUND

Evidence remains equivocal regarding the association of inflammation, a precursor to cardiovascular disease, and acute exposures to ambient air pollution from traffic-related particulate matter. Though youth with type 1 diabetes are at higher risk for cardiovascular disease, the relationship of inflammation and ambient air pollution exposures in this population has received little attention.

OBJECTIVES

Using five geographically diverse US sites from the racially- and ethnically-diverse SEARCH for Diabetes in Youth Cohort, we examined the relationship of acute exposures to PM2.5 mass, Atmospheric Dispersion Modeling System (ADMS)-Roads traffic-related PM concentrations near roadways, and elemental carbon (EC) with biomarkers of inflammation including interleukin-6 (IL-6), c-reactive protein (hs-CRP) and fibrinogen.

METHODS

Baseline questionnaires and blood were obtained at a study visit. Using a spatio-temporal modeling approach, pollutant exposures for 7 days prior to blood draw were assigned to residential addresses. Linear mixed models for each outcome and exposure were adjusted for demographic and lifestyle factors identified a priori.

RESULTS

Among the 2566 participants with complete data, fully-adjusted models showed positive associations of EC average week exposures with IL-6 and hs-CRP, and PM2.5 mass exposures on lag day 3 with IL-6 levels. Comparing the 25th and 75th percentiles of average week EC exposures resulted in 8.3% higher IL-6 (95%CI: 2.7%,14.3%) and 9.8% higher hs-CRP (95%CI: 2.4%,17.7%). We observed some evidence of effect modification for the relationships of PM2.5 mass exposures with hs-CRP by gender and with IL-6 by race/ethnicity.

CONCLUSIONS

Indicators of inflammation were associated with estimated traffic-related air pollutant exposures in this study population of youth with type 1 diabetes. Thus youth with type 1 diabetes may be at increased risk of air pollution-related inflammation. These findings and the racial/ethnic and gender differences observed deserve further exploration.

Associations between ambient air pollution and noise from road traffic with blood pressure and insulin resistance in children from Denmark

Supplemental Digital Content is available in the text.

Background:

Road traffic is a major source of air pollution and noise. Both exposures may contribute to increased blood pressure and metabolic disease; however, few studies have examined these relationships in children.

Objectives:

We aimed to investigate whether long-term exposures to air pollution and noise from road traffic were associated with increased blood pressure and insulin resistance in children.

Methods:

Cardiometabolic outcomes were derived from a follow-up examination of 629 children (10–15 years old) enrolled in the Danish National Birth Cohort. We evaluated associations with prenatal and postnatal residential exposure to nitrogen dioxide (NO₂) and noise from road traffic (L_den) using historical addresses and linear regression models.

Results:

A 10-unit increase in postnatal exposure to NO₂ and L_den was associated with a 0.31 (−0.87, 1.48) and 0.18 (−0.61, 0.96) mmHg changes in diastolic blood pressure, respectively. In contrast, both exposures were associated with decreased systolic blood pressure. After adjustment and mutual adjustment for NO₂, exposure to L_den was associated with a statistical significant decrease in systolic blood pressure both during prenatal and postnatal life, but the majority of the associations evaluated did not reach statistical significance. Inverse associations were observed for plasma fasting glucose, insulin, and HOMA of insulin resistance for both exposures, exposure windows, before and after adjustment.

Conclusions:

The findings do not support evidence of associations between long-term exposures to air pollution and road traffic noise, increased blood pressure, and a metabolic profile characteristic of increased risk for glucose intolerance or type 2 diabetes later in life.

Xenobiotic mediated diabetogenesis: Developmental exposure to dichlorvos or atrazine leads to type 1 or type 2 diabetes in Drosophila

The increased incidence of diabetes to the magnitude of a global epidemic is attributed to non-traditional risk factors, including exposure to environmental chemicals. However, the contribution of xenobiotic exposure during the development of an organism to the etiology of diabetes is not fully addressed. Developing stages are more susceptible to chemical insult, but knowledge on the consequence of the same to the onset of diabetes is residual. In this context, by using Drosophila melanogaster having conserved Insulin/Insulin growth factor-like signaling (IIS) as well as glucose homeostasis as a model, we evaluated the potential of developmental exposure to dichlorvos (DDVP, an organophosphorus pesticide) or atrazine (herbicide) to cause diabetes in exposed organisms. Flies exposed to DDVP during their development display insulin deficiency or type 1 diabetes (T1D) while those exposed to atrazine show insulin resistance or type 2 diabetes (T2D), suggesting that exposure to these xenobiotics during organismal development can result in diabetes and that different mechanisms underlie pesticide mediated diabetes. We show that oxidative stress-mediated c-Jun N-terminal kinase (JNK) signaling activation underlies insulin resistance in flies exposed to atrazine during their development while DDVP-mediated T1D involves activation of caspase-mediated cell death pathway. Mitigation of oxidative stress through over-expression of SOD2 in atrazine (20μg/ml) exposed flies, revealed significantly decreased oxidative stress levels and reduced phosphorylation of JNK. Moreover, glucose and Akt phosphorylation levels in SOD2 over-expression flies exposed to atrazine were comparable to those in controls, suggesting restoration in insulin sensitivity. Therefore, exposure to xenobiotics during development is a common risk factor for the development of type 1 or type 2 diabetes. Accordingly, the present study cautions against the use of such diabetogenic pesticides. Also, mitigation of oxidative stress or anti-oxidant supplementation could be a potential therapy for xenobiotic mediated type 2 diabetes.

Air Pollution, Oxidative Stress, and Diabetes: a Life Course Epidemiologic Perspective

PURPOSE OF REVIEW

Ambient air pollution is strongly linked to cardiovascular and respiratory diseases. We summarize available published evidence regarding similar associations with diabetes across the life course.

RECENT FINDINGS

We performed a life-course survey of the recent literature, including prenatal, gestational, childhood/adolescence, and adult exposures to air pollution. Oxidative stress is identified as a key factor in both metabolic dysfunction and the effects of air pollution exposure, especially from fossil fuel combustion products, providing a plausible mechanism for air pollution-diabetes associations. The global burden of diabetes attributed to air pollution exposure is substantial, with a recent estimate that ambient fine particulate matter (PM_2.5) exposure contributes to more than 200,000 deaths from diabetes annually. There is a growing body of literature linking air pollution exposure during childhood and adulthood with diabetes etiology and related cardiometabolic biomarkers. A small number of studies found that exposure to air pollution during pregnancy is associated with elevated gestational diabetes risk among mothers. Studies examining prenatal air pollution exposure and diabetes risk among the offspring, as well as potential transgenerational effects of air pollution exposure, are very limited thus far. This review provides insight into how air pollutants affect diabetes and other metabolic dysfunction-related diseases across the different life stages.

Emerging role of air pollution in autoimmune diseases

Autoimmune diseases (ADs) are a broad spectrum of disorders featured by the body's immune responses being directed against its own tissues, resulting in prolonged inflammation and subsequent tissue damage. Recently, the exposure to ambient air pollution has been implicated in the occurrence and development of ADs. Mechanisms linking air pollution exposures and ADs mainly include systemic inflammation, increased oxidative stress, epigenetic modifications induced by exposures and immune response caused by airway damage. The lung may be an autoimmunity initiation site in autoimmune diseases (ADs). Air pollutants can bind to the Aryl hydrocarbon receptor (AHR) to regulate Th17 and Treg cells. Oxidative stress and inducible bronchus associated lymphoid tissue caused by the pollutants can influence T, B cells, resulting in the production of proinflammatory cytokines. These cytokines stimulate B cell and dendritic cells, resulting in a lot of antibodies and self-reactive T lymphocytes. Moreover, air pollutants may induce epigenetic changes to contribute to ADs. In this review, we will concern the associations between air pollution and immune-inflammatory responses, as well as mechanisms linking air pollution exposure and autoimmunity. In addition, we focus on the potential roles of air pollution in major autoimmune diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), and type 1 diabetes mellitus (T1DM).

Exposure to environmental chemicals and type 1 diabetes: an update

This narrative review summarises recently published epidemiological and in vivo experimental studies on exposure to environmental chemicals and their potential role in the development of type 1 diabetes mellitus (T1DM). These studies focus on a variety of environmental chemical exposures, including to air pollution, arsenic, some persistent organic pollutants, pesticides, bisphenol A and phthalates. Of the 15 epidemiological studies identified, 14 include measurements of exposures during childhood, 2 include prenatal exposures and 1 includes adults over age 21. Together, they illustrate that the role of chemicals in T1DM may be complex and may depend on a variety of factors, such as exposure level, timing of exposure, nutritional status and chemical metabolism. While the evidence that these exposures may increase the risk of T1DM is still preliminary, it is critical to investigate this possibility further as a means of preventing T1DM.

Ambient urban dust particulate matter reduces pathologic T cells in the CNS and severity of EAE

BACKGROUND

Autoimmune diseases have increased in incidence and prevalence worldwide. While genetic predispositions play a role, environmental factors are a major contributor. Atmospheric particulate matter (PM) is a complex mixture composed of metals, nitrates, sulfates and diverse adsorbed organic compounds like polycyclic aromatic hydrocarbons (PAHs) and dioxins. Exposure to atmospheric PM aggravates autoimmune diseases such as type 1 diabetes, rheumatoid arthritis, multiple sclerosis, and systemic lupus erythematosus, among others. PAHs and dioxins are known aryl hydrocarbon receptor (AHR) ligands. The AHR modulates T cell differentiation and directs the balance between effector and regulatory T cells in vitro and in experimental autoimmune encephalomyelitis (EAE), a murine model of autoimmune disease. This study aims to identify pathways that contribute to autoimmune disease and their potential use as therapeutic targets to alleviate symptoms and the need for global immunosuppression. This study tests the hypothesis that atmospheric PM enhances effector T cell differentiation and aggravates autoimmune disease.

RESULTS

An atmospheric ambient urban dust PM sample, standard reference material (SRM)1649b, was tested for its effects on autoimmunity. SRM1649b PM enhanced Th17 differentiation in an AHR-dependent manner in vitro, however intranasal treatment of SRM1649b PM delayed onset of EAE and reduced cumulative and peak clinical scores. Chronic and acute intranasal exposure of SRM1649b PM delayed onset of EAE. Chronic intranasal exposure did not reduce severity of EAE while acute intranasal exposure significantly reduced severity of disease. Acute intranasal treatment of low dose SRM1649b PM had no effect on clinical score or day of onset in EAE. Delayed onset of EAE by intranasal SRM1649b PM was AHR-dependent in vivo. Oral gavage of SRM1649b PM, in the absence of AHR ligands in the diet, had no effect on day of disease onset or severity of EAE. Day 10 analysis of T cells in the CNS after intranasal treatment of SRM1649b PM showed a reduction of pathologic T cell subsets in vivo. Moreover, MOG-specific splenocytes require AHR to generate or maintain IL-10 producing cells and reduce IFNγ producing cells in vitro.

CONCLUSIONS

These results identify the AHR pathway as a potential target for driving targeted immunosuppression in the CNS in the context of atmospheric PM-mediated autoimmune disease. The effects of SRM1649b PM on EAE are dependent on route of exposure, with intranasal treatment reducing severity of EAE and delaying disease onset while oral gavage has no effect. Intranasal SRM1649b PM reduces pathologic T cells in the CNS, specifically Th1 cells and Th1Th17 double positive cells, leading to reduced severity of EAE and AHR-dependent delayed disease onset. Additionally, SRM1649b PM treatment of antigen-specific T cells leads to AHR-dependent increase in percent IL-10 positive cells in vitro. These findings may shed light on the known increase of infection after exposure to atmospheric PM and serve as the first step in identifying components of the AHR pathway responsible for Th1-mediated immunosuppression in response to atmospheric PM exposure.

The Aryl Hydrocarbon Receptor as an Immune-Modulator of Atmospheric Particulate Matter-Mediated Autoimmunity

This review examines the current literature on the effects of atmospheric particulate matter (PM) on autoimmune disease and proposes a new role for the aryl hydrocarbon receptor (AHR) as a modulator of T cells in PM-mediated autoimmune disease. There is a significant body of literature regarding the strong epidemiologic correlations between PM exposures and worsened autoimmune diseases. Genetic predispositions account for 30% of all autoimmune disease leaving environmental factors as major contributors. Increases in incidence and prevalence of autoimmune disease have occurred concurrently with an increase in air pollution. Currently, atmospheric PM is considered to be the greatest environmental health risk worldwide. Atmospheric PM is a complex heterogeneous mixture composed of diverse adsorbed organic compounds such as polycyclic aromatic hydrocarbons (PAHs) and dioxins, among others. Exposure to atmospheric PM has been shown to aggravate several autoimmune diseases. Despite strong correlations between exposure to atmospheric PM and worsened autoimmune disease, the mechanisms underlying aggravated disease are largely unknown. The AHR is a ligand activated transcription factor that responds to endogenous and exogenous ligands including toxicants present in PM, such as PAHs and dioxins. A few studies have investigated the effects of atmospheric PM on AHR activation and immune function and demonstrated that atmospheric PM can activate the AHR, change cytokine expression, and alter T cell differentiation. Several studies have found that the AHR modulates the balance between regulatory and effector T cell functions and drives T cell differentiation in vitro and in vivo using murine models of autoimmune disease. However, there are very few studies on the role of AHR in PM-mediated autoimmune disease. The AHR plays a critical role in the balance of effector and regulatory T cells and in autoimmune disease. With increased incidence and prevalence of autoimmune disease occurring concurrently with increases in air pollution, potential mechanisms that drive inflammatory and exacerbated disease need to be elucidated. This review focuses on the AHR as a potential mechanistic target for modulating T cell responses associated with PM-mediated autoimmune disease providing the most up-to-date literature on the role of AHR in autoreactive T cell function and autoimmune disease.

Traffic-Related Air Pollution and Child BMI-A Study of Prenatal Exposure to Nitrogen Oxides and Body Mass Index in Children at the Age of Four Years in Malmö, Sweden

Traffic-related air pollution could be a danger to the health of children. Earlier studies have linked prenatal exposure to an increased risk of a range of diseases and negative health outcomes, including overweight and obesity. Presently, a knowledge gap exists in investigating the risk of overweight and obesity among children exposed to lower levels of air pollution in utero. This study aimed to investigate the relationship between prenatal traffic-related air pollution (nitrogen dioxides (NO_x) and traffic density) and childhood overweight and obesity in Malmö, Sweden. A cohort, based on attendance of a four-year check-up examination at Swedish Child Health Care (CHC) centers, and a parent-assessed questionnaire provided data on body-mass index adjusted for four-year-old children (ISO-BMI) as well as socioeconomic and health variables. We estimated exposure by using traffic density and levels of NO_x at the maternal geocoded residential level. Analysis of 5815 children was performed using binary logistic regression models. This study showed no associations of increased risk for childhood overweight or obesity through to prenatal exposure to NO_x in this low-exposure setting. We further suggest analysis of risks related to exposure levels ranging between the ones presented here and those proposed in previous literature.

Differential effects of diesel exhaust particles on T cell differentiation and autoimmune disease

Background

Exposure to particulate matter (PM) has been associated with increased incidence and severity of autoimmune disease. Diesel PM is primarily composed of an elemental carbon core and adsorbed organic compounds such as polycyclic aromatic hydrocarbons (PAHs) and contributes up to 40% of atmospheric PM. The organic fraction (OF) of PM excludes all metals and inorganics and retains most organic compounds, such as PAHs. Both PM and OF increase inflammation in vitro and aggravate autoimmune disease in humans. PAHs are known aryl hydrocarbon receptor (AHR) ligands. The AHR modulates T cell differentiation and effector function in vitro and in experimental autoimmune encephalomyelitis (EAE), a murine model of autoimmune disease. This study aims to identify whether the total mass or active components of PM are responsible for activating pathways associated with exposure to PM and autoimmune disease. This study tests the hypothesis that active components present in diesel PM and their OF enhance effector T cell differentiation and aggravate autoimmune disease.

Results

Two different diesel samples, each characterized for their components, were tested for their effects on autoimmunity. Both diesel PM enhanced effector T cell differentiation in an AHR-dose-dependent manner and suppressed regulatory T cell differentiation in vitro. Both diesel PM aggravated EAE in vivo. Fractionated diesel OFs exhibited the same effects as PM in vitro, but unlike PM, only one diesel OF aggravated EAE. Additionally, both synthetic PAH mixtures that represent specific PAHs found in the two diesel PM samples enhanced Th17 differentiation, however one lost this effect after metabolism and only one required the AHR.

Conclusions

These findings suggest that active components of PM and not total mass are driving T cell responses in vitro, but in vivo the PM matrix and complex mixtures adsorbed to the particles, not just the OF, are contributing to the observed EAE effects. This implies that examining OF alone may not be sufficient in vivo. These data further suggest that bioavailability and metabolism of organics, especially PAHs, may have an important role in vivo.

Electronic supplementary material

The online version of this article (10.1186/s12989-018-0271-3) contains supplementary material, which is available to authorized users.

Impact of long-term air pollution exposure on metabolic control in children and adolescents with type 1 diabetes: results from the DPV registry

AIMS/HYPOTHESIS

Studies on the association between air pollution and metabolic control in children and adolescents with type 1 diabetes are rare and findings are inconsistent. We examined the relationship between air pollution variables (particulate matter with an aerodynamic diameter <10 μm [PM₁₀], NO₂ and accumulated ozone exposure [O₃-AOT]) and metabolic variables (HbA_1c and daily insulin dose [U/kg body weight]) in children and adolescents with type 1 diabetes.

METHODS

We investigated 37,372 individuals with type 1 diabetes aged <21 years, documented between 2009 and 2014 in 344 German centres of the prospective diabetes follow-up registry (Diabetes-Patienten-Verlaufsdokumentation [DPV]). Long-term air pollution exposure (annual and quinquennial means) data were linked to participants via the five-digit postcode areas of residency. Cross-sectional multivariable regression analysis was used to examine the association between air pollution and metabolic control.

RESULTS

After comprehensive adjustment, an interquartile range increase in O₃-AOT was associated with a lower HbA_1c (-3.7% [95% CI -4.4, -3.0]). The inverse association between O₃-AOT and HbA_1c persisted after additional adjustment for degree of urbanisation or additional adjustment for PM₁₀. Moreover, the inverse association remained stable in further sensitivity analyses. No significant associations between HbA_1c and PM₁₀ or NO₂ were found. No association was observed between any of the three air pollutants and insulin dose.

CONCLUSIONS/INTERPRETATION

The inverse association between O₃-AOT and HbA_1c could not be explained by regional differences in diabetes treatment or by other differences between urban and rural areas. Furthermore, our results remained stable in sensitivity analyses. Further studies on the association between air pollution and HbA_1c in children and adolescents with type 1 diabetes are needed to confirm our observed association and to elucidate underlying mechanisms.

Developmental Exposure to Endocrine Disrupting Chemicals and Type 1 Diabetes Mellitus

Exposure to endocrine disrupting chemicals (EDCs) may have implications for the development of type 1 diabetes mellitus (T1DM), especially if exposure occurs during development. Exposure to EDCs during fetal or early life can disrupt the development of both the immune system and the pancreatic beta cells, potentially increasing susceptibility to T1DM later in life. Developmental exposure to some EDCs can cause immune system dysfunction, increasing the risk of autoimmunity. In addition, developmental exposure to some EDCs can affect beta cell development and function, influencing insulin secretion. These changes may increase stress on the beta cells, and identify them as a target to the immune system. Developmental exposure to EDCs that disrupt metabolism by increasing insulin resistance or obesity may also stress the beta cells. Exposure to these EDCs during development may play a role in the pathogenesis of T1DM, and requires further research.

Genetic Variants of the Receptor for Advanced Glycation End-products in Susceptibility to Type 2 Diabetes Mellitus in Primary Hypertensive Patients

Diabetes mellitus is frequently comorbid with hypertension, which is approximately twice as common as diabetes mellitus in China. We designed a case-control association study to inspect the susceptibility of the receptor for advanced glycation end-products (RAGE) gene 6 variants to type 2 diabetes mellitus (T2DM) in 2199 patients with primary hypertension (1252 diabetic cases and 947 nondiabetic controls). The genotypes/alleles of −429T > C and 82Gly > Ser variants differed significantly between the two groups, and their associations with T2DM were significant after Bonferroni correction. Two variants, −374T > A and I/D, showed only marginal associations with T2DM. Haplotype analysis of above 4 significant variants indicated that a low-penetrance haplotype simultaneously bearing −429C and 82Ser alleles was overrepresented in cases relative to controls (4.75% vs. 1.72%, P < 0.001). Moreover, the predictive capability of 6 variants was significantly superior to available risk factors, with better goodness-of-fit. A predictive nomogram of 4 baseline risk factors and 2 variants of statistical significance was structured, with a good predictive accuracy (C-index = 0.761, P < 0.001). Taken together, our findings highlighted a contributory role of the RAGE gene, especially its two functional variants −429T > C and 82Gly > Ser, in susceptibility to T2DM in primary hypertensive patients, which may aid early detection and risk assessment for high-risk individuals.

The Influence of Quercetin on Maternal Immunity, Oxidative Stress, and Inflammation in Mice with Exposure of Fine Particulate Matter during Gestation

The objective is to investigate the influence of PM2.5 exposure on peripheral blood lymphocyte subsets in pregnant mice and the antagonism of quercetin on adverse effects induced by PM2.5 exposure. Pregnant mice were randomly divided into control group, PM2.5 model group and 3 quercetin intervention groups. Dams in all groups except the control group were exposed to PM2.5 suspension by intratracheal instillation on gestational day (GD) 3, 6, 9, 12 and 15. Meanwhile, each dam was given 0.15% carboxymethylcellulose sodium (CMCS) (control group & PM2.5 model group) and different doses of quercetin (quercetin intervention groups) by gavage once a day from GD0 to GD17. The percentage of lymphocyte subsets, Biomarkers of systemic inflammation injuries (IL-2, IL-6, IL-8 & TNF-α) and oxidative stress indicators (CAT, GSH & HO-1) in peripheral blood of the dams were analyzed. The number of T cells increased, accompanied by increased level of IL-2, IL-6, IL-8 and HO-1 due to PM2.5 exposure. Less CD4+ and CD8+ T cells were counted in 100 mg/kg quercetin intervention group, compared with PM2.5 model group. Quercetin may inhibit cytokine production, especially in IL-6 and IL-8 and may upgrade the level of HO-1. Our findings indicate that PM2.5 could significantly influence the distribution of T-lymphocyte subsets, activate inflammatory reaction and elevate oxidative stress level in peripheral blood of pregnant mice. Certain dose of quercetin administration during pregnancy may protect the dams against the adverse effects through various ways.

A joint ERS/ATS policy statement: what constitutes an adverse health effect of air pollution? An analytical framework

The American Thoracic Society has previously published statements on what constitutes an adverse effect on health of air pollution in 1985 and 2000. We set out to update and broaden these past statements that focused primarily on effects on the respiratory system. Since then, many studies have documented effects of air pollution on other organ systems, such as on the cardiovascular and central nervous systems. In addition, many new biomarkers of effects have been developed and applied in air pollution studies.This current report seeks to integrate the latest science into a general framework for interpreting the adversity of the human health effects of air pollution. Rather than trying to provide a catalogue of what is and what is not an adverse effect of air pollution, we propose a set of considerations that can be applied in forming judgments of the adversity of not only currently documented, but also emerging and future effects of air pollution on human health. These considerations are illustrated by the inclusion of examples for different types of health effects of air pollution.

Fetal growth and air pollution - A study on ultrasound and birth measures

Air pollution has been suggested to affect fetal growth, but more data is needed to assess the timing of exposure effects by using ultrasound measures. It is also important to study effects in low exposure areas to assess eventual thresholds of effects. The MAPSS (Maternal Air Pollution in Southern Sweden) cohort consists of linked registry data for around 48,000 pregnancies from an ultrasound database, birth registry and exposure data based on residential addresses. Measures of air pollution exposure were obtained through dispersion modelling with input data from an emissions database (NO_x) with high resolution (100-500m grids). Air pollution effects were assessed with linear regressions for the following endpoints; biparietal diameter, femur length, abdominal diameter and estimated fetal weight measured in late pregnancy and birth weight and head circumference measured at birth. We estimated negative effects for NO_x; in the adjusted analyses the decrease of abdominal diameter and femur length were -0.10 (-0.17, -0.03) and -0.13 (-0.17, -0.01)mm, respectively, per 10µg/m³ increment of NO_x. We also estimated an effect of NO_x-exposures on birth weight by reducing birth weight by 9g per 10µg/m³ increment of NO_x. We estimated small but statistically significant effects of air pollution on late fetal and birth size and reduced fetal growth late in pregnancy in a geographic area with levels below current WHO air quality guidelines.

Effect of Fine Particulate Matter (PM2.5) on Rat Placenta Pathology and Perinatal Outcomes

Background

Fine particulate matter with aerodynamic diameters smaller than 2.5 μm (PM_2.5) has been reported to cause adverse effects on human health. Evidence has shown the association between PM_2.5 exposure and adverse perinatal outcomes, and the most common method is epidemiological investigation. We wished to investigate the impact of PM_2.5 on placenta and prenatal outcomes and its related mechanisms in a rat model.

Material/Methods

Pregnant rats were exposed to a low PM_2.5 dose (15 mg/kg) with intratracheal instillation at pregnant day 10 and day 18, while the controls received an equivalent volume normal saline. All rats received cesarean section 24 h after the last intratracheal instillation and were sacrificed with anesthesia. Blood routine tests (BRT) and interleukin-6 (IL-6) were detected for analyzing inflammation and blood coagulation. Placenta tissue sections underwent pathologic examination, and the levels of homogenate glutathione peroxidase (GSH-Px) and methane dicarboxylic aldehyde (MDA) were determined for oxidative stress estimation.

Results

Increased absorbed blastocysts, and lower maternal weight gain and fetal weight were found in the PM_2.5 exposure group compared to controls (p<0.05). Exposure to PM_2.5 caused a significant increase of blood mononuclear cells (PBMC), platelets, and IL-6 levels (P<0.01). There were no differences in GSH-Px and MDA of placenta homogenate between the 2 groups (P>0.05). Placenta pathological examination demonstrated thrombus and chorioamnionitis in the PM_2.5 exposure group.

Conclusions

PM_2.5 exposure can result in placental pathological changes and adverse perinatal outcomes. The placental inflammation and hypercoagulability with vascular thrombosis may play important roles in placental impairment, but oxidative stress appears to be less important.

Systemic metabolic derangement, pulmonary effects, and insulin insufficiency following subchronic ozone exposure in rats

Acute ozone exposure induces a classical stress response with elevated circulating stress hormones along with changes in glucose, protein and lipid metabolism in rats, with similar alterations in ozone-exposed humans. These stress-mediated changes over time have been linked to insulin resistance. We hypothesized that acute ozone-induced stress response and metabolic impairment would persist during subchronic episodic exposure and induce peripheral insulin resistance. Male Wistar Kyoto rats were exposed to air or 0.25ppm or 1.00ppm ozone, 5h/day, 3 consecutive days/week (wk) for 13wks. Pulmonary, metabolic, insulin signaling and stress endpoints were determined immediately after 13wk or following a 1wk recovery period (13wk+1wk recovery). We show that episodic ozone exposure is associated with persistent pulmonary injury and inflammation, fasting hyperglycemia, glucose intolerance, as well as, elevated circulating adrenaline and cholesterol when measured at 13wk, however, these responses were largely reversible following a 1wk recovery. Moreover, the increases noted acutely after ozone exposure in non-esterified fatty acids and branched chain amino acid levels were not apparent following a subchronic exposure. Neither peripheral or tissue specific insulin resistance nor increased hepatic gluconeogenesis were present after subchronic ozone exposure. Instead, long-term ozone exposure lowered circulating insulin and severely impaired glucose-stimulated beta-cell insulin secretion. Thus, our findings in young-adult rats provide potential insights into epidemiological studies that show a positive association between ozone exposures and type 1 diabetes. Ozone-induced beta-cell dysfunction may secondarily contribute to other tissue-specific metabolic alterations following chronic exposure due to impaired regulation of glucose, lipid, and protein metabolism.

Type I diabetes in paediatric age in Apulia (Italy): Incidence and associations with outdoor air pollutants

AIM

This study aimed to explore Type 1 diabetes (T1D) incidence and possible relations with specific air pollutants in a large population of children, during a wide time period.

METHODS

T1D rates and trends were examined (2001-2013, GAM and Joinpoint Regression analysis) by data on the first hospitalization in all children (0-14 years) living in Apulia (Southern Italy, average yearly population aged 0-14 years in the examined period: 631,275 subjects), and linked with levels of PM10, NOx, CO and ozone.

RESULTS

A total of 1501 children were first discharged in the selected area with a diagnosis of T1D. Incidence decreased from 48.5 (95% CI 43.3; 54.0, 2001) to 16.9 per 100,000 (95% CI 13.7; 20.6, 2013), with differences according to age at onset (constant at 0-4 years, continuously decreasing at 5-9 years, decreasing until 2003 at 10-14 years), and with a positive relation with PM10--but not ozone, NOx and CO average air levels. The OR was 1.037 (1.002; 1.074) in the high tertile of PM10 concentrations, and mean incidence was higher with PM10 levels in the highest, than in the medium/reference tertile. Mean age at T1D onset was linked with yearly PM10 and ozone air levels.

CONCLUSIONS

On a wide period, a stable or decreased incidence of T1D was evident in children with early- or later onset of disease, respectively. PM10 exposure significantly affects the incidence of T1D, which might be considered, at least in part, a preventable condition.