Preconception and early pregnancy air pollution exposures and risk of gestational diabetes mellitus

Prenatal exposure to air pollution, maternal diabetes and preterm birth

Prenatal exposure to ambient air pollution has been associated with preterm birth in several studies. Associations between air pollution and gestational or pre-existing diabetes have been hypothesized but are not well established. We examined the association between air pollution exposure in pregnancy and gestational diabetes and whether the association between air pollution and preterm birth is modified by diabetes (gestational or pre-existing) in a highly polluted area of California. Birth certificates and hospital discharge data from all singleton births from 2000 to 2006 to women living in four counties in the San Joaquin Valley of California were linked to criteria air pollution and traffic density measurements at the geocoded maternal residence. Air pollutants were dichotomized at the highest quartile and compared to the lower three quartiles. Logistic regression models were adjusted for maternal race-ethnicity, age, education, payment of birth expenses, and prenatal care. There were consistent inverse associations between exposure to air pollution during the first two trimesters and gestational diabetes (statistically significant odds ratios (OR) less than 1). When stratified by any diabetes (gestational or pre-existing), associations between air pollution exposure during pregnancy and categories of preterm birth (20-27, 28-31, 32-33, 34-36 weeks) were generally similar with few exceptions of exposures to carbon monoxide (CO) and particulate matter < 2.5 µm (PM2.5). Those with diabetes and exposure higher levels of CO (in first trimester or entire pregnancy) or PM2.5 (in first trimester) had higher risk of extremely preterm birth (20-27 weeks) compared with those without diabetes. The associations between traffic-related air pollution and gestational diabetes were in the unexpected ("protective") direction. Among those with any diabetes, associations were stronger between CO and PM2.5 and extremely preterm birth.

Ambient Volatile Organic Compounds and Racial/Ethnic Disparities in Gestational Diabetes Mellitus: Are Asian/Pacific Islander Women at Greater Risk?

US Asian/Pacific Islander (API) communities experience high air pollution levels. APIs may be predisposed to pancreatic β-cell dysfunction and have the highest prevalence of gestational diabetes mellitus (GDM) compared with other racial/ethnic groups. Exposure to high levels of volatile organic compounds (VOCs) impairs pancreatic β-cell function, leading to insulin resistance, but racial/ethnic differences in this association are unexamined. We analyzed singleton deliveries (n = 220,065) from the Consortium on Safe Labor (2002-2008). Exposure to 14 VOCs in each hospital referral region was based on modified Community Multiscale Air Quality models. Logistic regression estimated odds ratios for GDM associated with high (≥75th percentile) versus low (<75th percentile) VOC exposure 3 months before conception and during the first trimester of pregnancy. Preconception and first-trimester exposure to high VOC levels was associated with increased odds of GDM among whites and APIs. GDM risk was significantly higher for APIs than whites for most VOCs. Preconception benzene exposure was associated with 29% (95% confidence interval: 12, 47) increased odds of GDM among whites compared with 45% (95% confidence interval: 16, 81) increased odds among APIs. These findings highlight environmental health disparities affecting pregnant women. Increased focus on GDM risk in US API communities is warranted.

Acute effects of air pollutants on adverse birth outcomes in Changsha, China: A population data with time-series analysis from 2015 to 2017

Evidence for the acute effects of air pollutants on adverse birth outcomes is not yet conclusive. Furthermore, there are no investigations relating to the association between air pollutants and macrosomia. The aim of this study was to determine the relationship between air pollutants and low birth weight, preterm birth, and macrosomia in Changsha. Time-series analysis, using a generalized additive model was applied. Data about the adverse birth outcomes was collected from 78 midwifery institutions. Air pollution data including SO2, NO2, particulate matter <10 μm in diameter (PM10), particulate matter <2.5 μm in diameter (PM2.5), O3, CO, and climate data were respectively collected from the Changsha Environmental Protection Agency and the Changsha Meteorological Bureau from January 2015 to December 2017. During the study period, there were 344,880 live births to be studied. In a single pollutant model, for every increase of 10 μg/m in PM10 and PM2.5, low birth weight increased by 0.12% (95% confidence interval [CI]: 0.01-0.23%) at a lag 06 and 0.44% (95% CI: 0.35-0.53%) at a lag 3, respectively. Preterm birth increased most by 1.60% (95% CI: 1.41-1.80%) at a lag 2 for every increase of 10 μg/m in SO2. The highest increases in macrosomia associated with a 10 μg/m increase in air pollutant were 3.53% (95% CI: 3.41-3.64%) for NO2 at lag 0, 3.33% (95% CI: 3.05-3.60%) for SO2 at lag03. Multi-pollutant models showed that only PM10 increased the low birth weight and preterm birth risk effect by 3.91% (95% CI: 3.67-4.12%) and 0.25% (95% CI: 0.14-0.37%). NO2 increased macrosomia risk by 4.14% (95% CI: 3.97-4.31%) with a 10 μg/m increase. There was no association observed between the air pollutants O3 and CO and adverse birth outcomes. Pregnant women should also take steps to limit their exposure to high levels of air pollutants during the final weeks of pregnancy.

Outdoor Air Pollution and Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

BACKGROUND

During the past 20 years, the prevalence of gestational diabetes mellitus (GDM) has increased by ∼10%-100% in several race/ethnicity groups. There is an association between ambient air pollution (AAP) and GDM. This study aimed to summarize the evidence about the association between AAP and GDM.

METHODS

PubMed, Embase, Scopus, Web of Science and Cochrane Library were searched from inception till Oct 2017. Studies about the association between ambient air pollutants levels and GDM were included. Pooled effect estimates and their 95% confidence interval (CI) were calculated using R.

RESULTS

Eight studies met the inclusion criteria. The odds of developing GDM upon exposure to CO (per 1 ppm), NO (per 1 ppb), NO2 (per 10 μg/m3), NOx (per 1 ppb), O3 (per 10 ppb), SO2 (per 10 ppb), PM10 (per 10 μg/m3) and PM2.5 (per 10 μg/m3) were 1.47 (95% CI 0.88-2.06), 1.04 (95% CI 1.03-1.06), 1 (95% CI 0.93-1.08), 1.02 (95% CI 1-1.04), 1.05 (95% CI 0.94-1.16), 1.39 (95% CI 1.04-1.73), 0.97 (95% CI 0.94-0.99) and 1.12 (95% CI 0.93-1.31), respectively.

CONCLUSION

The current literature showed evidence for an association between AAP and GDM. However, further well-designed studies are needed.

Air pollution, land use, and complications of pregnancy

BACKGROUND

Mounting evidence suggests that the natural and built environment can affect human health, but relatively few studies have considered links between features of the residential natural and built environment other than air pollution and complications of pregnancy.

OBJECTIVES

To quantify the impact of features of the maternal residential natural and built environments on risk of gestational diabetes mellitus (GDM), gestational hypertension and preeclampsia among 61,640 women who delivered at a single hospital in Rhode Island between 2002 and 2012.

METHODS

We estimated residential levels of ambient fine particulate matter (PM_2.5) and black carbon (BC) using spatiotemporal models, neighborhood green space using remote sensing and proximity to recreational facilities, and neighborhood blue space using distance to coastal and fresh water. We used logistic regression to separately estimate the association between each feature and GDM, gestational hypertension, and preeclampsia, adjusting for individual and neighborhood markers of socioeconomic status.

RESULTS

GDM, gestational hypertension, and preeclampsia were diagnosed in 8.0%, 5.0%, and 3.6% of women, respectively. We found 2nd trimester PM_2.5 (OR = 1.08, 95% CI: 1.00, 1.15 per interquartile range increase in PM_2.5) and living close to a major roadway (1.09, 95% CI: 1.00, 1.19) were associated with higher odds of GDM, while living <1 km from the coast was associated with lower odds of GDM (0.87, 95% CI: 0.78, 0.96). Living <500 m from a recreational facility was associated with lower odds of gestational hypertension (0.89, 95% CI: 0.80, 0.99). None of these features were associated with odds of preeclampsia. Results were qualitatively similar in mutually-adjusted models and sensitivity analyses.

CONCLUSIONS

In this small coastal US state, risk of GDM was positively associated with PM_2.5 and proximity to busy roadways, and negatively associated with proximity to blue space, highlighting the importance of the natural and built environment to maternal health.

Aerobic Exercise Preconception and During Pregnancy Enhances Oxidative Capacity in the Hindlimb Muscles of Mice Offspring

Liu, J, Lee, I, Feng, H-Z, Galen, SS, Hüttemann, PP, Perkins, GA, Jin, J-P, Hüttemann, M, and Malek, MH. Aerobic exercise preconception and during pregnancy enhances oxidative capacity in the hindlimb muscles of mice offspring. J Strength Cond Res 32(5): 1391-1403, 2018-Little is known about the effect of maternal exercise on offspring skeletal muscle health. The purpose of this study, therefore, was to determine whether maternal exercise (preconception and during pregnancy) alters offspring skeletal muscle capillarity and mitochondrial biogenesis. We hypothesized that offspring from exercised dams would have higher capillarity and mitochondrial density in the hindlimb muscles compared with offspring from sedentary dams. Female mice in the exercise condition had access to a running wheel in their individual cage 30 days before mating and throughout pregnancy, whereas the sedentary group did not have access to the running wheel before mating and during pregnancy. Male offspring from both groups were killed when they were 2 months old, and their tissues were analyzed. The results indicated no significant (p > 0.05) mean differences for capillarity density, capillarity-to-fiber ratio, or regulators of angiogenesis such as VEGF-A and TSP-1. Compared with offspring from sedentary dams, however, offspring from exercised dams had an increase in protein expression of myosin heavy chain type I (MHC I) (∼134%; p = 0.009), but no change in MHC II. For mitochondrial morphology, we found significant (all p-values ≤ 0.0124) increases in mitochondrial volume density (∼55%) and length (∼18%) as well as mitochondria per unit area (∼19%). For mitochondrial enzymes, there were also significant (all p-values ≤ 0.0058) increases in basal citrate synthase (∼79%) and cytochrome c oxidase activity (∼67%) in the nonoxidative muscle fibers as well as increases in basal (ATP) (∼52%). Last, there were also significant mean differences in protein expression for regulators (FIS1, Lon protease, and TFAM) of mitochondrial biogenesis. These findings suggest that maternal exercise before and during pregnancy enhances offspring skeletal muscle mitochondria functionality, but not capillarity.

Air pollution exposure during pregnancy: maternal asthma and neonatal respiratory outcomes

PURPOSE

Maternal asthma increases adverse neonatal respiratory outcomes, and pollution may further increase risk. Air quality in relation to neonatal respiratory health has not been studied.

METHODS

Transient tachypnea of the newborn (TTN), asphyxia, and respiratory distress syndrome (RDS) were identified using medical records among 223,375 singletons from the Consortium on Safe Labor (2002-2008). Community Multiscale Air Quality models estimated pollutant exposures. Multipollutant Poisson regression models calculated adjusted relative risks of outcomes for interquartile range increases in average exposure. Maternal asthma and preterm delivery were evaluated as effect modifiers.

RESULTS

TTN risk increased after particulate matter (PM) less than or equal to 10-micron exposure during preconception and trimester one (9-10%), and whole-pregnancy exposure to PM less than or equal to 2.5 microns (PM2.5; 17%) and carbon monoxide (CO; 10%). Asphyxia risk increased after exposure to PM2.5 in trimester one (48%) and whole pregnancy (84%), CO in trimester two and whole pregnancy (28-32%), and consistently for ozone (34%-73%). RDS risk was associated with increased concentrations of nitrogen oxides (33%-42%) and ozone (9%-21%) during all pregnancy windows. Inverse associations were observed with several pollutants, particularly sulfur dioxide. No interaction with maternal asthma was observed. Restriction to term births yielded similar results.

CONCLUSIONS

Several pollutants appear to increase neonatal respiratory outcome risks.

Exposure to air pollution during preconceptional and prenatal periods and risk of hypertensive disorders of pregnancy: a retrospective cohort study in Seoul, Korea

Background

Previous studies suggested associations between prenatal exposure to air pollution and hypertensive disorders of pregnancy. We explored the associations between ambient concentrations of five major air pollutants during preconceptional and prenatal periods and three hypertensive disorders of pregnancy in Seoul, Korea, using a population-representative cohort.

Methods

We obtained heath and demographic data of pregnant women residing in Seoul for 2002–2013 from the Korean National Health Insurance Service–National Sample Cohort. For mother’s individual exposures to air pollution, we computed concentrations of particulate matter ≤10 μm in diameter (PM₁₀), nitrogen dioxide (NO₂), carbon monoxide (CO), sulfur dioxide (SO₂), and ozone (O₃) during 1, 3, 6, and 12 months to birth using regulatory monitoring data in Seoul. The associations between air pollution and hypertensive disorders were explored by using logistic regression models after adjusting for individual confounders.

Results

Among 18,835 pregnant women in Seoul, 0.6, 0.5, and 0.4% of women developed gestational hypertension, preeclampsia, and preeclampsia requiring magnesium sulfate (Mg-preeclampsia), respectively. Although most odds ratios (ORs) were not statistically significant, we found increasing risk gradients with disease severity depending on the pollutant. There was the association between PM₁₀ during 6 months to birth and gestational hypertension (OR for an interquartile range increase = 1.68 [95% confidence interval = 1.09–2.58]). NO₂ and ozone during 12 and 1 month, respectively, before birth were associated with Mg-preeclampsia (1.43 [1.01–2.03], 1.53 [1.03–2.27]).

Conclusions

We observed positive associations of exposure to some air pollutants before and during pregnancy with hypertensive disorders of pregnancy among the Korean general population. Future studies with refined exposure metrics should confirm our findings.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-1982-z) contains supplementary material, which is available to authorized users.

Developmental Origins of Disease: Emerging Prenatal Risk Factors and Future Disease Risk

Purpose of review

Many of the diseases and dysfunctions described in the paradigm of the developmental origins of health and disease have been studied in relation to prenatal nutrition or environmental toxicant exposures. Here, we selectively review the current research on four exposures-two nutritional and two environmental-that have recently emerged as prenatal risk factors for long-term health outcomes.

Recent findings

Recent studies have provided strong evidence that prenatal exposure to (1) excessive intake of sugar-sweetened beverages, (2) unhealthy dietary patterns, (3) perfluoroalkyl substances, and (4) fine particulate matter, may increase risk of adverse health outcomes, such as obesity, cardiometabolic dysfunction, and allergy/asthma.

Summary

Emerging prenatal nutritional factors and environmental toxicants influence offspring long-term health. More work is needed to identify the role of paternal exposures and maternal exposures during the preconception period and to further elucidate causality through intervention studies. The ubiquity of these emerging nutritional and environmental exposures makes this area of inquiry of considerable public health importance.

Residential proximity to major roadways and traffic in relation to outcomes of in vitro fertilization

BACKGROUND

Emerging data from animal and human studies suggest that traffic-related air pollution adversely affects early pregnancy outcomes; however evidence is limited.

OBJECTIVE

We examined whether residential proximity to major roadways and traffic, as proxies for traffic-related air pollution, are associated with in vitro fertilization (IVF) outcomes.

METHODS

This analysis included 423 women enrolled in the Environment and Reproductive Health (EARTH) Study, a prospective cohort study, who underwent 726 IVF cycles (2004-2017). Using geocoded residential addresses collected at study entry, we calculated the distance to nearest major roadway and the traffic density within a 100 m radius. IVF outcomes were abstracted from electronic medical records. We used multivariable generalized linear mixed models to evaluate the associations between residential proximity to major roadways and traffic density and IVF outcomes adjusting for maternal age, body mass index, race, education level, smoking status, and census tract median income.

RESULTS

Closer residential proximity to major roadways was statistically significantly associated with lower probability of implantation and live birth following IVF. The adjusted percentage of IVF cycles resulting in live birth for women living ≥400 m from a major roadway was 46% (95% CI 36, 56%) compared to 33% (95% CI 26, 40%) for women living <50 m (p-for-comparison, 0.04). Of the intermediate outcomes, there were suggestive associations between living closer to major roadways and slightly higher estradiol trigger concentrations (p-trend = 0.16) and lower endometrial thickness (p-trend = 0.06). Near-residence traffic density was not associated with outcomes of IVF.

CONCLUSION

Closer residential proximity to major roadways was related to reduced likelihood of live birth following IVF.

Air Pollution and Glucose Metabolism: An Analysis in Non-Diabetic Participants of the Heinz Nixdorf Recall Study

BACKGROUND

Despite the importance of understanding the connection between air pollution exposure and diabetes, studies investigating links between air pollution and glucose metabolism in nondiabetic adults are limited.

OBJECTIVE

We aimed to estimate the association of medium-term air pollution exposures with blood glucose and glycated hemoglobin A1c (HbA1c) among nondiabetics.

METHODS

This study included observations from nondiabetic participants (n_obs=7,108) of the population-based Heinz Nixdorf Recall study at baseline (2000–2003) and follow-up examination (2006–2008). Daily fine particulate matter (aerodynamic diameter≤2.5 μm, PM_2.5; aerodynamic diameter≤10 μm, PM₁₀), accumulation mode particle number (PN_AM), and nitrogen dioxide (NO₂) exposures were estimated at participants’ residences using the spatiotemporal European Air Pollution Dispersion (EURAD) chemistry transport model. We evaluated the associations between medium-term air pollution exposures (28- and 91-d means) and glucose metabolism measures using mixed linear regression and adjusting for season, meteorology, and personal characteristics. A range of other exposure windows (1-, 2-, 3-, 7-, 14-, 45-, 60-, 75-, 105-, 120-, and 182-d means) were also evaluated to identify potentially relevant biological windows.

RESULTS

We observed positive associations between PM_2.5 and PN_AM exposures and blood glucose levels [e.g., 28-d PM_2.5: 0.91 mg/dL (95% CI: 0.38, 1.44) per 5.7 μg/m³]. PM_2.5, PM₁₀, and PN_AM exposures were positively associated with HbA1c [e.g., 91-d PM_2.5: 0.07 p.p. (95% CI: 0.04, 0.10) per 4.0 μg/m³]. Mean exposures during longer exposure windows (75- to 105-d) were most strongly associated with HbA1c, whereas 7- to 45-d exposures were most strongly associated with blood glucose. NO₂ exposure was not associated with blood glucose or with HbA1c.

CONCLUSIONS

Medium-term PM and PN_AM exposures were positively associated with glucose measures in nondiabetic adults. These findings indicate that reducing ambient air pollution levels may decrease the risk of diabetes. https://doi.org/10.1289/EHP2561.

Using electronic health record data for environmental and place based population health research: a systematic review

PURPOSE

We conducted a systematic review of literature published on January 2000-May 2017 that spatially linked electronic health record (EHR) data with environmental information for population health research.

METHODS

We abstracted information on the environmental and health outcome variables and the methods and data sources used.

RESULTS

The automated search yielded 669 articles; 128 articles are included in the full review. The number of articles increased by publication year; the majority (80%) were from the United States, and the mean sample size was approximately 160,000. Most articles used cross-sectional (44%) or longitudinal (40%) designs. Common outcomes were health care utilization (32%), cardiometabolic conditions/obesity (23%), and asthma/respiratory conditions (10%). Common environmental variables were sociodemographic measures (42%), proximity to medical facilities (15%), and built environment and land use (13%). The most common spatial identifiers were administrative units (59%), such as census tracts. Residential addresses were also commonly used to assign point locations, or to calculate distances or buffer areas.

CONCLUSIONS

Future research should include more detailed descriptions of methods used to geocode addresses, focus on a broader array of health outcomes, and describe linkage methods. Studies should also explore using longitudinal residential address histories to evaluate associations between time-varying environmental variables and health outcomes.

Exposure to arsenic in tap water and gestational diabetes: A French semi-ecological study

INTRODUCTION

The increase in the prevalence of gestational diabetes mellitus (GDM) and its consequences for mother and children prompts research on their risk factors including environmental factors. Studies on exposure to arsenic (As) in tap water and the risk of GDM have not provided conclusive evidence, particularly when levels of exposure were low (from 10 to 50µg As/L). The main objective of this study was to assess the association between exposure to As in tap water and the risk of GDM.

METHODS

A semi-ecological study was conducted from births recorded at the University Hospital of Clermont-Ferrand, France, in 2003, 2006 and 2010. Individual medical/obstetric data were available. As exposure was estimated from the concentrations of As measured during sanitary control of tap water supplied in the mothers' commune of residence (aggregate data). French guidelines for As in tap water were used to identify groups potentially exposed, designated "As +" (≥ 10µg As/L) and "As -" (< 10µg As/L). Multivariate logistic regression analysis was performed.

RESULTS

5053 women (5.7% with a GDM) were included. Overall, women in the As + group had a higher risk of GDM than those in the As - group (adjusted OR = 1.62; 95%CI: 1.01-2.53). Stratified analysis of pre-pregnancy body mass index (BMI) showed a positive association only for obese or overweight women (adjusted OR = 2.30; 95%CI: 1.13-4.50).

CONCLUSION

This French semi-ecological study provides additional arguments for an association between As exposure and the risk of GDM in particular in a context of low exposure. Further studies are needed to assess a potential interaction between As exposure and body mass index.

Maternal Exposure to Air Pollutants and Risk of Gestational Diabetes Mellitus in Taiwan

Mounting evidence has shown an increased risk of gestational diabetes mellitus (GDM) in association with elevated exposure to air pollution. However, limited evidence is available concerning the effect of specific air pollutant(s) on GDM incidence. We conducted this case-control study on 6717 mothers with GDM diagnosed in 2006–2013 and 6717 age- and year of delivery-matched controls to further address the risk of GDM in relation to specific air pollutant. Both cases and controls were selected from a cohort of 1-million beneficiaries of Taiwan’s National Health Insurance program registered in 2005. Maternal exposures to mean daily air pollutant concentration, derived from 76 fixed air quality monitoring stations within the 12-week period prior to pregnancy and during the 1st and 2nd trimesters, were assessed by the spatial analyst method (i.e., ordinary kriging) with the ArcGIS software. After controlling for potential confounders and other air pollutants, an increase in pre-pregnancy exposure of 1 inter-quartile range (IQR) for PM_2.5 and SO₂ was found to associate with a significantly elevated odds ratio (OR) of GDM at 1.10 (95% confidence interval (CI) 1.03–1.18 and 1.37 (95% CI 1.30–1.45), respectively. Exposures to PM_2.5 and SO₂ during the 1st and 2nd trimesters were also associated with significantly increased ORs, which were 1.09 (95% CI 1.02–1.17) and 1.07 (95% CI 1.01–1.14) for PM_2.5, and 1.37 (95% CI 1.30–1.45) and 1.38 (95% CI 1.31–1.46) for SO₂. It was concluded that higher pre- and post-pregnancy exposures to PM_2.5 and SO₂ for mothers were associated with a significantly but modestly elevated risk of GDM.

Gestational diabetes mellitus and exposure to ambient air pollution and road traffic noise: A cohort study

BACKGROUND

Road traffic is a main source of air pollution and noise. Both exposures have been associated with type 2 diabetes, but associations with gestational diabetes mellitus (GDM) have been studied less.

OBJECTIVES

We aimed to examine single and joint associations of exposure to air pollution and road traffic noise on GDM in a prospective cohort.

METHODS

We identified GDM cases from self-reports and hospital records, using two different criteria, among 72,745 singleton pregnancies (1997-2002) from the Danish National Birth Cohort. We modeled nitrogen dioxide (NO₂) and noise from road traffic (L_den) exposure at all pregnancy addresses.

RESULTS

According to the two diagnostic criteria: the Danish clinical guidelines, which was our main outcome, and the WHO standard during recruitment period, a total of 565 and 210 women, respectively, had GDM. For both exposures no risk was evident for the common Danish criterion of GDM. A 10-μg/m³ increase in NO₂ exposure during first trimester was, however, associated with an increased risk of WHO-GDM (adjusted odds ratio (OR)=1.24; 95% confidence interval (CI): 1.03, 1.49). The corresponding OR associated with a 10-dB higher road traffic noise level was 1.15 (0.94 to 1.18). In mutually adjusted models the OR for NO₂ remained similar 1.22 (0.98, 1.53) whereas that for road traffic noise decreased to 1.03 (0.80, 1.32). Significant associations were also observed for exposure averaged over the 2nd and 3rd trimesters and the full pregnancy.

CONCLUSIONS

No risk was evident for the common Danish criterion of GDM. NO₂ was associated with higher risk for GDM according to the WHO criterion, which might be due to selection bias.

Gestational diabetes mellitus was related to ambient air pollutant nitric oxide during early gestation

BACKGROUND

Ambient air pollution has been linked to the risk of gestational diabetes mellitus (GDM). However, evidence of this association is limited, and no study has examined the effects of nitric oxide (NO).

OBJECTIVE

This study investigated the association between air pollution exposure during gestation and GDM.

METHODS

The Taiwan Birth Cohort Study database was used to examine the association between the risk of GDM and all routinely monitored air pollutants among 21,248 women who were pregnant during 2004-2005. We further employed a two-pollutant model for confirming the effect of each pollutant on GDM.

RESULTS

After the exclusion criteria were applied, 19,606 women were included in the final analysis. Among them, 378 (1.9%) had been diagnosed as having GDM. These women were older and had higher BMIs than the women without GDM. The risks of GDM onset were significantly associated with NO exposure during the first [adjusted OR (aOR): 1.05, 95% confidence interval (CI): 1.02-1.08] and second (aOR: 1.05, 95%CI: 1.02-1.08) trimesters. Under the two-pollutant model, the effect of NO exposure was also significant during the first (aOR: 1.05, 95%CI: 1.02-1.08) and second (aOR: 1.05, 95%CI: 1.02-1.09) trimesters.

CONCLUSION

The results indicated that exposure to higher NO levels during pregnancy increases the risk of GDM.

Fine-particulate matter (PM2.5), a risk factor for rat gestational diabetes with altered blood glucose and pancreatic GLUT2 expression

Recent studies have shown an intriguing association between air pollution and diabetic risk. This study was to investigate the impact of fine particulate matter (PM2.5) on glucose consequences and pancreas glucose transporter2 (GLUT2) expression in a gestational diabetes mellitus (GDM) rat model. GDM rats were exposed to a low PM2.5 dose during pregnancy. After exposure, interleukin-6 (IL-6) and blood routine tests (BRT) were detected. Pancreas underwent pathologic examination. The levels of pancreatic homogenate glutathione peroxidase (GSH-Px), methane dicarboxylic aldehyde (MDA) and GLUT2 were detected. There were lower maternal body weight gain and fetal weight in the PM2.5 group. Exposure to PM2.5 caused increased absorbed blastocyst number, higher blood mono-nuclear cells (PBMC), platelets and IL-6 levels. The postprandial blood glucose (PBG) was elevated at most time points after exposure. The pancreas of PM2.5 exposed rats revealed periductal inflammation under pathological examination. The pancreatic GSH-Px significantly reduced and MDA increased in exposed group. The pancreatic GLUT2 expression was decreased after PM2.5 exposure. Our study provides direct evidence that PM2.5 exposure can result in pancreatic pathological changes and glycemic consequences in GDM rats. The oxidative response and inflammation are involved in PM2.5 increased risk of pancreatic impairment and glycemic consequences.

Maternal childhood cardiometabolic risk factors and pregnancy complications

PURPOSE

The influence of childhood health on later-life health outcomes is increasingly hypothesized but rarely tested. We examined the relationship between cardiometabolic indicators in childhood and risk of pregnancy-induced hypertension, preeclampsia, and gestational diabetes.

METHODS

Childhood measurements from 755 women in the Bogalusa Heart Study included body mass index, systolic and diastolic blood pressure (SBP and DBP), low- and high-density lipoprotein cholesterol, total cholesterol, triglycerides, insulin, and glucose. Average childhood values were estimated by area under the curve computed from longitudinal quadratic random-effects growth models to account for the unequally spaced repeated measures. Women reported pregnancy complications, and medical records were linked to interview data where possible. Log-Poisson models predicted adjusted risk associated with an interquartile range increase in cardiometabolic indicators.

RESULTS

Elevated childhood insulin was associated with 10%-15% increased risk across the three outcomes. Elevated childhood SBP was associated with preeclampsia (SBP RR = 1.50, 95% CI: 1.13, 2.01) and SBP, DBP, and body mass index predicted pregnancy-induced hypertension (SBP RR = 2.15, 95% CI: 1.65, 2.82; DBP RR = 1.83, 95% CI: 1.38, 2.43; BMI RR = 1.67, 95% CI: 1.41, 1.98). Blood pressure mediated the association between childhood body mass index and pregnancy-induced hypertension.

CONCLUSIONS

Results suggest the potential long-term impact of early-life cardiometabolic profiles on complications of pregnancy.

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.

Association between particulate matter 2.5 and diabetes mellitus: A meta-analysis of cohort studies

Aims/Introduction

The present meta‐analysis was carried out to assess the association between exposure to the level of atmospheric particulate matter 2.5 (PM2.5; fine particulate matter with aerodynamic diameter less than 2.5 μm) and type 2 diabetes mellitus or gestational diabetes mellitus (GDM).

Materials and Methods

We searched the Medline, EMBASE, Cochrane and Web of Science databases to obtain articles according to the responding literature search strategies. Among a total of 279 identified articles, 55 were reviewed in depth, of which 10 articles (11 cohort studies) satisfied the inclusion criteria. Only cohort studies that disclosed the association between PM2.5 and type 2 diabetes mellitus or GDM were included in this article. A fixed‐effects model was selected if P > 0.1 and I² < 50%; otherwise, a random‐effects model would be used to calculate the total effect value. Subgroup analysis was further carried out according to the types of diabetes mellitus (type 2 diabetes mellitus and GDM). The relative risk was used to estimate the association between PM2.5 and diabetes mellitus.

Results

The positive associations between PM2.5 and the incidence of type 2 diabetes mellitus were found in the long‐term exposure period (relative risk 1.25, 95% confidence interval 1.10–1.43), which showed that with every 10‐μg/m³ increase in PM2.5, the risk of type 2 diabetes mellitus would increase by 25% in the long‐term exposure. Although the significant associations were not identified between maternal exposure to PM2.5 and GDM in the first trimester, the second trimester and the entire pregnancy periods, we could conclude that maternal exposure to PM2.5 in the entire pregnancy period would be more likely to lead to developing GDM (relative risk 1.162, 95% confidence interval 0.806–1.675) than the other two periods.

Conclusions

Long‐term exposure to PM2.5 would be more likely to lead to developing type 2 diabetes mellitus, but more studies would be required to confirm the association between PM2.5 and GDM. It might be a wise to take effective measures to reduce PM2.5 exposure in vulnerable populations, especially for pregnant women.

Fine particulate matter (PM2.5), a risk factor of rat gestational diabetes with altered blood glucose and pancreatic GLUT2 expression

Recent studies have shown an association between air pollution and diabetic risk. This study was to investigate the impact of fine particulate matter (PM2.5) on glucose consequences and pancreas glucose transporter 2 (GLUT2) expression and its related mechanisms in a gestational diabetes mellitus (GDM) rat model. GDM rats were exposed to a low PM2.5 dose while the controls received saline. Interleukin-6 (IL-6) and blood routine tests (BRT) were detected for analyzing coagulation and inflammation. Pancreas tissues underwent pathologic examination, the levels of homogenate glutathione peroxidase (GSH-Px), and methane dicarboxylic aldehyde (MDA) were detected for oxidative stress estimation, and the degree of GLUT2 expression of pancreas was analyzed. There were lower maternal body weight gain and fetal weight in the PM2.5 group. Exposure to PM2.5 caused increased absorbed blastocyst number and postprandial blood glucose (PBG) blood mono-nuclear cells (PBMC), platelets, and IL-6 levels. The pancreas of PM2.5 exposed rats revealed inflammation under pathological examination. The pancreatic GSH-Px significantly reduced and MDA increased and GLUT2 protein expression decreased after exposure. Our study provides direct evidence that PM2.5 exposure can result in glycemic consequences in GDM rats. The oxidative response and inflammation are involved in PM2.5 increased risk of adverse maternal and fetal consequences.

Urinary phthalate and phthalate alternative metabolites and isoprostane among couples undergoing fertility treatment

BACKGROUND

Epidemiological data suggest associations between phthalate exposures to a variety of adverse reproductive outcomes including reduced sperm quality and reproductive success. While mechanisms of these associations are not fully elucidated, oxidative stress has been implicated as a potential mediator. We examined associations of urinary metabolites of phthalates and phthalate alternative plasticizers with oxidative stress among couples seeking fertility treatment.

METHODS

Seventeen urinary plasticizer metabolites and 15-F2t isoprostane, a biomarker of oxidative stress, were quantified in spot samples from 50 couples seeking fertility treatment who enrolled in the Sperm Environmental Epigenetics and Development Study during 2014-2015.

RESULTS

In multivariable analyses, percent change in isoprostane was positively associated with interquartile range increases for the oxidative metabolites of di-2-ethylhexyl phthalate, [mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP; 20.0%, p=0.02), mono-2-ethyl-5-oxohexyl phthalate (MEOHP; 24.1%, p=0.01), and mono-2-ethyl-5-carboxypentyl phthalate (MECPP; 24.1%, p=0.004)], mono-isobutyl phthalate (MiBP; 17.8%, p=0.02), mono-hydroxyisobutyl phthalate (MHiBP; 27.5%, p=0.003), and cyclohexane-1,2-dicarboxylic acid mono-hydroxy-isononyl ester (MHINCH; 32.3%, p=0.002). Stratification of participants by sex revealed that isoprostane was positively associated with MHiBP (41.4%, p=0.01) and monocarboxy-isononyl phthalate (MCNP; 26.0%, p=0.02) among females and MEOHP (35.8%, p=0.03), MiBP (29.2%, p=0.01), MHiBP (34.7%, p=0.007) and MHINCH (49.0%, p=0.002) among males.

CONCLUSIONS

Our results suggest that exposure to phthalates and phthalate replacements are associated with higher levels of oxidative stress in a sex-specific manner. Additional studies are needed to replicate our findings and to examine the potential health implications of the use of phthalates and alternative phthalates in consumer end products.

Placental Nutrient Transport in Gestational Diabetic Pregnancies

Maternal obesity during pregnancy is rising and is associated with increased risk of developing gestational diabetes mellitus (GDM), defined as glucose intolerance first diagnosed in pregnancy (1). Fetal growth is determined by the maternal nutrient supply and placental nutrient transfer capacity. GDM-complicated pregnancies are more likely to be complicated by fetal overgrowth or excess adipose deposition in utero. Infants born from GDM mothers have an increased risk of developing cardiovascular and metabolic disorders later in life. Diverse factors, such as ethnicity, age, fetal sex, clinical treatment for glycemic control, gestational weight gain, and body mass index among others, represent a challenge for studying underlying mechanisms in GDM subjects. Determining the individual roles of glucose intolerance, obesity, and other factors on placental function and fetal growth remains a challenge. This review provides an overview of changes in placental macronutrient transport observed in human pregnancies complicated by GDM. Improved knowledge and understanding of the alterations in placenta function that lead to pathological fetal growth will allow for development of new therapeutic interventions and treatments to improve pregnancy outcomes and lifelong health for the mother and her children.

Combining land use regression models and fixed site monitoring to reconstruct spatiotemporal variability of NO2 concentrations over a wide geographical area

The epidemiological research benefits from an accurate characterization of both spatial and temporal variability of exposure to air pollution. This work aims at proposing a method to combine the high spatial resolution of Land Use Regression (LUR) models with the high temporal resolution of fixed site monitoring data, to model spatiotemporal variability of NO₂ over a wide geographical area in Northern Italy. We developed seasonal LUR models to reconstruct the spatial distribution of a scaling factor that relates local concentrations to those measured at two reference central sites, one for the northern flat area and one for the southern mountain area. We calculated the daily average concentrations at 19 locations spread over the study areas as the product of the local scaling factor and the reference central site concentrations. We evaluated model performance comparing modeled and measured NO₂ data. LUR model's R² ranges from 0.76 to 0.92. The main predictors refers substantially to traffic, industrial land use, buildings volume and altitude a.s.l. The model's performance in reproducing measured concentrations was satisfactory. The temporal variability of concentrations was well captured: Spearman correlation between model and measures was >0.7 for almost all sites. Model's average absolute errors were in the order of 10μgm^-3. The model for the southern area tends to overestimate measured concentrations. Our modeling framework was able to reproduce spatiotemporal differences in NO₂ concentrations. This kind of model is less data-intensive than usual regional atmospheric models and it may be very helpful to assess population exposure within studies in which individual relevant exposure occurs along periods of days or months.

Association of temporal distribution of fine particulate matter with glucose homeostasis during pregnancy in women of Chiayi City, Taiwan

BACKGROUND

To investigate the effects of fine particulate matter (PM_2.5) on the indicators of glucose homeostasis during pregnancy.

METHODS

A total of 3589 non-diabetic pregnant women who underwent a 3-h 100-g oral glucose tolerance test (OGTT) were enrolled from a tertiary teaching hospital in Chiayi City, Taiwan between 2006 and 2014. Fasting, 1-h, 2-h, and 3-h glucose levels after an OGTT were used as indicators of glucose homeostasis. PM_2.5 and other air pollution data were obtained from one fixed-site monitoring station (Chiayi City station) operated by Taiwan Environmental Protection Administration (EPA). We used mixed models for indicators of glucose homeostasis to estimate the effects of PM_2.5. The models were adjusted for individual-specific effects (nulliparous status, age, body mass index, season, and year) and the moving averages of temperature and relative humidity in the corresponding study period.

RESULTS

There were significant relationships between PM_2.5 and the glucose homeostasis indicators, including fasting, 1-h, 2-h, and 3-h glucose levels in the single-pollutant covariate-adjusted model. The pre-screening 1-month to 1-year moving averages of IQR increases in PM_2.5 were significantly associated with elevated fasting OGTT glucose levels (1.32-5.87mg/dL). The two-pollutant covariate-adjusted models had similar results.

CONCLUSIONS

We found positive associations between PM_2.5 and OGTT glucose levels during pregnancy. The association was especially pronounced for the fasting and 1-h glucose levels. PM_2.5 exposure in the second trimester may enhance this effect. Exposure to PM_2.5 was associated with glucose homeostasis during pregnancy.

Maternal arsenic exposure and gestational diabetes and glucose intolerance in the New Hampshire birth cohort study

BACKGROUND

Gestational diabetes mellitus (GDM) is a major pregnancy complication with detrimental effects for both mothers and their children. Accumulating evidence has suggested a potential role for arsenic (As) exposure in the development of GDM, but current studies have not assessed As exposure from water, urine or toenail samples.

METHODS

We investigated the association between As exposure and risk of glucose intolerance and GDM among 1151 women enrolled in the New Hampshire Birth Cohort Study. Arsenic was measured in home well water and via biomarkers (i.e., maternal urine collected ~24-28 weeks gestation and toenail clippings collected 2 weeks postpartum).

RESULTS

A total of 105 (9.1 %) of women were diagnosed with glucose intolerance and 14 (1.2 %) of women were diagnosed with GDM. A total of 10.3 % of women had water As levels above 10 μg/L, with a mean As level of 4.2. Each 5 μg/L increase in As concentration in home well water was associated with a ~10 % increased odds of GDM (OR: 1.1, 95 % CI 1.0, 1.2). A positive and statistically significant association also was observed between toenail As and GDM (OR: 4.5, 95 % CI 1.2, 16.6), but not urinary arsenic (OR: 0.8, 95 % CI 0.3, 2.4). In a stratified analysis, the association between water As and GDM and glucose intolerance was largely limited to obese women (OR: 1.7, 95 % CI 1.0, 2.8).

CONCLUSIONS

Our findings support the role of As exposure via water from private wells in the incidence of GDM and that this association may be modified by body composition.

Association between serum concentrations of persistent organic pollutants and gestational diabetes mellitus in primiparous women

BACKGROUND

There is growing evidence that persistent organic pollutants (POPs) may play an important role in increasing the risk of gestational diabetes mellitus (GDM).

OBJECTIVES

The aim of this study was to examine the association between polychlorinated biphenyls (PCBs, 10 congeners) and polybrominated diphenyl ethers (PBDEs, 8 congeners) and GDM in primiparous women with no family history of diabetes in first-degree relatives during the third trimester of pregnancy.

METHODS

This case-control study was performed among the three university hospitals of Tehran University of Medical Sciences. Serum samples were collected from cases (n=70) that were diagnosed with GDM and from controls (n=70) with a normal pregnancy that attended the same hospital for a routine prenatal visit. Pollutant levels were analyzed by Gas Chromatography Mass Spectrometry (GC/MS).

RESULTS

Logistic regression analyses manifested the positive association between total POPs (sum of total PCBs and PBDEs) (Odds ratio (OR)=1.61, 95% CI: 1.31-1.97, p-value <0.0001) and total PCBs (OR=1.75, 95% CI: 1.35-2.27, p-value<0.0001) and GDM considering confounding variables (age, gestational age, pre-pregnancy body mass index (BMI), and total maternal serum lipid). In addition, we found a positive association between total PBDEs and GDM (OR =2.21; 95% CI: 1.48-3.30, p-value <0.0001). Finally, we found a positive association between Ln PCB 187, 118 and Ln PBDE 99, 28 with GDM. Meanwhile a negative association between Ln PCB 28 and GDM was established.

CONCLUSION

Our data suggest that exposure to certain POPs (PCBs and PBDEs) could be a potential modifying risk factor for GDM.

Placental Nitrosative Stress and Exposure to Ambient Air Pollution During Gestation: A Population Study

The placenta plays a crucial role in fetal growth and development through adaptive responses to perturbations of the maternal environment. We investigated the association between placental 3-nitrotyrosine (3-NTp), a biomarker of oxidative stress, and exposure to air pollutants during various time windows of pregnancy. We measured the placental 3-NTp levels of 330 mother-newborn pairs enrolled in the Environmental Influence on Ageing in Early Life (ENVIRONAGE) Study, a Belgian birth cohort study (2010-2013). Daily concentrations of particulate matter with an aerodynamic diameter ≤2.5 µm (PM2.5), black carbon (BC), and nitrogen dioxide were interpolated for each mother's residence using a spatiotemporal interpolation method. Placental 3-NTp levels, adjusted for covariates, increased by 35.0% (95% confidence interval (CI): 13.9, 60.0) for each interquartile-range increment in entire-pregnancy PM2.5 exposure. The corresponding estimate for BC exposure was 13.9% (95% CI: -0.21, 29.9). These results were driven by the first (PM2.5: 29.0% (95% CI: 4.9, 58.6); BC: 23.6% (95% CI: 4.4, 46.4)) and second (PM2.5: 39.3% (95% CI: 12.3, 72.7)) gestational exposure windows. This link between placental nitrosative stress and exposure to fine particle air pollution during gestation is in line with experimental evidence on cigarette smoke and diesel exhaust exposure. Further research is needed to elucidate potential health consequences experienced later in life through particle-mediated nitrosative stress incurred during fetal life.

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.

Preterm birth and air pollution: Critical windows of exposure for women with asthma

BACKGROUND

Ambient air pollutants may increase preterm birth (PTB) risk, but critical exposure windows are uncertain. The interaction of asthma and pollutant exposure is rarely studied.

OBJECTIVE

We sought to assess the interaction of maternal asthma and air pollutant exposures in relation to PTB risk.

METHODS

Electronic medical records for 223,502 US deliveries were linked with modified Community Multiscale Air Quality model outputs. Logistic regression with generalized estimating equations estimated the odds ratio and 95% CIs for PTB on the basis of the interaction of maternal asthma and particulate matter with aerodynamic diameter of less than 2.5 microns and particulate matter with aerodynamic diameter of less than 10 microns, ozone (O3), nitrogen oxides (NOx), sulfur dioxide (SO2), and carbon monoxide (CO) per interquartile range. For each gestational week 23 to 36, exposures among women who delivered were compared with those remaining pregnant. Three-month preconception, whole pregnancy, weeks 1 to 28, and the last 6 weeks of gestation averages were also evaluated.

RESULTS

On assessing PTB by gestational week, we found that significant asthma interactions were sporadic before 30 weeks but more common during weeks 34 to 36, with higher risk among mothers with asthma for NOx, CO, and SO2 exposure and an inverse association with O3 in week 34. Odds of PTB were significantly higher among women with asthma for CO and NOx exposure preconception and early in pregnancy. In the last 6 weeks of pregnancy, PTB risk associated with particulate matter with aerodynamic diameter of less than 10 microns was higher among women with asthma.

CONCLUSIONS

Mothers with asthma may experience a higher risk for PTB after exposure to traffic-related pollutants such as CO and NOx, particularly for exposures 3-months preconception and in the early weeks of pregnancy.

Current Methods and Challenges for Epidemiological Studies of the Associations Between Chemical Constituents of Particulate Matter and Health

Epidemiological studies have been critical for estimating associations between exposure to ambient particulate matter (PM) air pollution and adverse health outcomes. Because total PM mass is a temporally and spatially varying mixture of constituents with different physical and chemical properties, recent epidemiological studies have focused on PM constituents. Most studies have estimated associations between PM constituents and health using the same statistical methods as in studies of PM mass. However, these approaches may not be sufficient to address challenges specific to studies of PM constituents, namely assigning exposure, disentangling health effects, and handling measurement error. We reviewed large, population-based epidemiological studies of PM constituents and health and describe the statistical methods typically applied to address these challenges. Development of statistical methods that simultaneously address multiple challenges, for example, both disentangling health effects and handling measurement error, could improve estimation of associations between PM constituents and adverse health outcomes.

Air pollution exposure and gestational diabetes mellitus among pregnant women in Massachusetts: a cohort study

BACKGROUND

Rodent and human studies suggest an association between air pollution exposure and type 2 diabetes mellitus, but the extent to which air pollution is associated with gestational diabetes mellitus (GDM) is less clear.

METHODS

We used the Massachusetts Registry of Vital Records to study primiparous women pregnant from 2003-2008 without pre-existing diabetes. We used satellite-based spatiotemporal models to estimate first and second trimester residential particulate (PM2.5) exposure and geographic information systems to estimate neighborhood traffic density. We obtained GDM status from birth records. We performed logistic regression analyses adjusted for sociodemographics on the full cohort and after stratification by maternal age and smoking habits.

RESULTS

Of 159,373 women, 5,381 (3.4 %) developed GDM. Residential PM2.5 exposure ranged 1.3-19.3 μg/m(3) over the second trimester. None of the exposures were associated with GDM in the full cohort [e.g. OR 0.99 (95 % CI: 0.95, 1.03) for each interquartile range (IQR) increment in second trimester PM2.5]. There were also no consistent associations after stratification by smoking habits. When the cohort was stratified by maternal age, women less than 20 years had 1.36 higher odds of GDM (95 % CI: 1.08, 1.70) for each IQR increment in second trimester PM2.5 exposure.

CONCLUSIONS

Although we found no evidence of an association between air pollution exposure and GDM among all women in our study, greater exposure to PM2.5 during the second trimester was associated with GDM in the youngest age stratum.

Mitochondrial oxidative DNA damage and exposure to particulate air pollution in mother-newborn pairs

BACKGROUND

Studies emphasize the importance of particulate matter (PM) in the formation of reactive oxygen species and inflammation. We hypothesized that PM exposure during different time windows in pregnancy influences mitochondrial 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, which is an established biomarker for oxidative stress, in both maternal and foetal blood.

METHODS

We investigated maternal (n = 224) and cord blood (n = 293) from mother-newborn pairs that were enrolled in the ENVIRONAGE birth cohort. We determined mitochondrial 8-OHdG by quantitative polymerase chain reaction (qPCR). Multivariable regression models were used to assess the association between mitochondrial 8-OHdG with PM10 and PM2.5 exposure over various time windows during pregnancy.

RESULTS

In multivariable analysis, PM10 exposure during the entire pregnancy was positively associated with levels of mitochondrial 8-OHdG in maternal blood. For an IQR increment in PM10 exposure an increase of 18.3 % (95 % confidence interval (CI): 5.6 to 33.4 %, p = 0.004) in 8-OHdG was observed. PM10 exposure during the last trimester of pregnancy was positively associated with levels of 8-OHdG (28.1, 95 % CI: 8.6 to 51.2 %, p = 0.004, for an IQR increment in PM10). In a similar way, PM2.5 exposure was significantly associated with an increase of mitochondrial 8-OHdG levels in maternal blood during the entire pregnancy (13.9, 95 % CI: 0.4 to 29.4 %, p = 0.04 for an IQR increment in PM2.5 exposure) and third trimester of pregnancy (28.1, 95 % CI: 3.6 to 58.4 %, p = 0.02 for an IQR increment in PM2.5 exposure). In umbilical cord blood, 8-OHdG levels were significantly associated with PM10 exposure during first and second trimester of pregnancy with respectively an increase of 23.0 % (95 % CI: 5.9 to 42.8 %, p = 0.007) and 16.6 % (95 % CI: 1.8 to 33.5 %, p = 0.03) for an IQR increment in PM10 exposure.

CONCLUSIONS

We found PM-associated increased mitochondrial oxidative DNA damage during pregnancy in both mothers and their newborns. Accordingly, our study showed that particulate air pollution exposure in early life plays a role in increasing systemic oxidative stress, at the level of the mitochondria, both in mother and foetus.

Using Electronic Health Records for Population Health Research: A Review of Methods and Applications

The use and functionality of electronic health records (EHRs) have increased rapidly in the past decade. Although the primary purpose of EHRs is clinical, researchers have used them to conduct epidemiologic investigations, ranging from cross-sectional studies within a given hospital to longitudinal studies on geographically distributed patients. Herein, we describe EHRs, examine their use in population health research, and compare them with traditional epidemiologic methods. We describe diverse research applications that benefit from the large sample sizes and generalizable patient populations afforded by EHRs. These have included reevaluation of prior findings, a range of diseases and subgroups, environmental and social epidemiology, stigmatized conditions, predictive modeling, and evaluation of natural experiments. Although studies using primary data collection methods may have more reliable data and better population retention, EHR-based studies are less expensive and require less time to complete. Future EHR epidemiology with enhanced collection of social/behavior measures, linkage with vital records, and integration of emerging technologies such as personal sensing could improve clinical care and population health.

Proteomic-driven biomarker discovery in gestational diabetes mellitus: a review

Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance with onset or first recognition during pregnancy and it affects 18% of pregnant women worldwide. GDM is considered a high-risk state which may lead to type II diabetes which is associated with an increase in a number of interrelated adverse perinatal outcomes. Given the fact that the progress of a successful pregnancy is dependent on the intricate communication between several biological molecules, identification of the proteomic profile perturbations in women with GDM is expected to help in understanding the disease pathogenesis and also discovery of clinical biomarker(s). In recent years, both gel-free and gel-based proteomics have been extensively investigated for improving maternal and child health. Although there are several reports integrating various aspects of proteomics in pregnancy related diseases such as preeclampsia, extensive Pubmed search shows no review so far on the application of proteomics in gestational diabetes. In this review, we focus on various high-throughput proteomic technologies for the identification of unique biosignatures and biomarkers responsible for the early prediction of GDM. Further, different analytical strategies and biological samples involved in proteomic analysis of this pregnancy-related disease are discussed.This article is part of a Special Issue entitled: Proteomics in India.

Epidemiology of air pollution and diabetes

Air pollution affects a large proportion of the global population. Air pollutants are hypothesized to exert their effects via impaired endothelial function, elevated systemic inflammation, mitochondrial dysfunction, and oxidative stress, all of which are hallmarks of type 2 diabetes (T2D). Here we review epidemiological studies aimed at answering whether diabetes patients are more vulnerable to ambient (outdoor) air pollution exposure and whether air pollution is associated with diabetes development or other predisposing conditions for T2D. Current evidence suggests an association between air pollution exposure and T2D, but more critical analysis is warranted. Understanding the associations between air pollution exposure and the development of T2D is critical in our efforts to control sources of air pollution and their impact on the disease.