Ambient ozone and incident diabetes: A prospective analysis in a large cohort of African American women

Association of long-term ozone exposure with the incidence and progression of hypertension, diabetes, and chronic kidney disease: A national retrospective cohort study

Evidence suggests that ozone is associated with an increased risk of hypertension, diabetes, or chronic kidney disease (CKD). However, the associations of ozone exposure with the dynamic progression of these diseases among Asian population remain unknown. This study included 9,256,945 participants from Taiwan's National Health Insurance Research Database between 2006 and 2021. Multimorbidity was defined as the coexistence of CKD and either hypertension or diabetes. The ordinary kriging method was used to estimate daily concentrations of ozone, sulfur dioxide, carbon monoxide, nitrogen dioxide, suspended fine particles, and suspended particles. Then, five-year average concentrations of pollutants were calculated. We performed multi-state survival models to analyze the association between ozone and dynamic progression of these diseases. During follow-up, 3,555,498 participants experienced hypertension, diabetes, or CKD; 656,515 experienced multimorbidity; and 792,555 died. Ozone exposure was significantly associated with incidence of the results in all transitions. The hazard ratios of each IQR (3.57 ppb) increment in ozone for the transition to incident disease were 1.016 [95 % confidence interval (CI): 1.014, 1.017], for the transition to death were 1.04 [95 % CI: 1.036, 1.043], for the transition to multimorbidity were 1.015 [95 % CI: 1.012, 1.017]. Furthermore, with each IQR increase of ozone, the hazard ratios for transition from the disease incidence to death and from multimorbidity to death were 1.03 [95 % CI: 1.026, 1.033] and 1.007 [95 % CI: 1.002, 1.013], respectively. Our results suggest long-term exposure to ozone might be an important determinant for the incidence and dynamic progression of hypertension, diabetes, and CKD in Taiwan.

Long-term low-level ozone exposure and the incidence of type 2 diabetes mellitus and glycemic levels: A prospective cohort study from Southwest China

BACKGROUND

This study investigated the relationship between long-term low-level ozone (O3) exposure, type 2 diabetes mellitus (T2DM) incidence, and glycemic levels within a prospective cohort in Southwest China, especially in regions with relatively low air pollution levels.

METHOD

Between 2010 and 2020, the Guizhou Population Health Cohort Study (GPHCS) enrolled 9280 participants, who were followed up from 2016 to 2020. A total of 7317 participants (aged 18-95 years, mean 43.70 ± 14.89 years) were included in the final analysis. Time-dependent Cox regression models were used to evaluate the hazard ratios (HRs) between O3 exposure and T2DM incidence and its 95 % confidence intervals (CIs). Generalized linear model (GLM) assessed the association between O3 exposure and fasting blood glucose (FBG) levels.

RESULTS

During a median follow-up period of 6.58 (6.25, 8.42) years, 763 participants were diagnosed with T2DM. For every 1 standard deviation (SD) increase in O3 exposure (Mean ± SD: 67.23 ± 2.16 μg/m³) during the 6 years before baseline, the incidence of T2DM increased by 32.4 % (HR = 1.324, 95 % CI: 1.216, 1.442), while FBG levels rose by 0.081 mmol/L (β = 0.081, 95 % CI: 0.035,0.126). These associations persisted after adjusting for potential confounders, including PM2.5 and temperature. Stratified analyses revealed stronger associations in Han Chinese and urban populations.

CONCLUSION

This study provides robust evidence that even long-term exposure to low-level O3, below the World Health Organization (WHO) guideline value, is significantly associated with increased T2DM incidence and elevated FBG levels. These findings stress the need for stricter air pollution control measures to reduce the incident T2DM caused by long-term low-level O3 exposure and enhance public health protections.

Outdoor air pollution exposure and the risk of type 2 diabetes mellitus: A systematic umbrella review and meta-analysis

The association between different air pollutants and Type 2 Diabetes Mellitus (T2DM) is a growing topic of interest in public health research. This umbrella review and meta-analysis aimed to consolidate current literature on the association between various outdoor air pollutants and T2DM. Subgroups and dose-response relationships were also analyzed to further quantify the association, especially by the factors such as the type of pollutants, duration of exposure, and geographical variation, etc. A thorough literature search of three databases revealed a total of 71 records for umbrella review and 1524 records for meta-analysis where 8 studies were included in the final review of umbrella review and 46 studies for meta-analysis. The evaluation of the study's quality in umbrella review and meta-analysis were conducted using the AMSTAR 2 criteria and the Newcastle-Ottawa Scale (NOS), respectively. Exposure to Particulate Matter (PM) 2.5, PM10, Nitrogen dioxides (NO2) and Ozone (O3) were significantly associated with the risk of T2DM [OR = 1.12 (95% Confidence Interval (CI): 1.09, 1.15), 1.12 (95% CI: 1.06, 1.18), 1.09 (95%CI: 1.07, 1.12), 1.05 (95%CI: 1.03, 1.08), respectively] and subgroup analysis further revealed that PM2.5, PM10, and NO2 associations were confounded by factors such as ages, study design, regions of exposure and air pollution concentration levels. Lastly, only exposure to PM10 had a significant dose-response relationship with the risk of T2DM (p-value = 0.000). These findings further emphasized the need for standardized methods in conducting air pollution research and additional research on other air pollutants to further explore the relationships between these air pollutants and T2DM.

Exposure to air pollution is associated with adipokines in midlife women: The Study of Women's Health Across the Nation

This study examined the associations between ambient air pollution exposure, including fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3), with serum levels of high molecular weight (HMW) adiponectin, leptin, and soluble leptin receptors (sOB-R) in midlife women. The analysis included 1551 participants from the Study of Women's Health Across the Nation (median age = 52.3 years) with adipokine data from 2002 to 2003. Annual air pollution exposures were assigned by linking residential addresses with high-resolution machine learning models at a 1-km2 resolution. Multivariable linear regression and Bayesian kernel machine regression (BKMR) were used to evaluate the associations for individual pollutants and pollutant mixtures. After adjusting for confounders in linear regression models, an interquartile range increase in PM2.5 (2.5 μg/m3) was associated with a 4.6 % lower HMW adiponectin level (95 % CI: -8.8 %, -0.3 %). Exposure to air pollutant mixtures showed negative associations with HMW adiponectin and positive associations with leptin levels in BKMR models. These findings suggest that exposures to PM2.5, NO2, and O3 are associated with adverse levels of adipokines, which may contribute to obesity-related outcomes. Further research is needed to confirm these findings and explore the underlying biological mechanisms.

Ozone induced multigenerational glucose and lipid metabolism disorders in Drosophila

Ozone (O3), a persistent pollutant, poses a significant health threat. However, research on its multigenerational toxicity remains limited. Leveraging the Drosophila model with its short lifespan and advanced genetic tools, we explored the effects of O3 exposure across three generations of fruit flies. The findings revealed that O3 disrupted motility, body weight, stress resistance, and oxidative stress in three generations of flies, with varying effects observed among them. Transcriptome analysis highlighted the disruption of glucose metabolism-related pathways, encompassing gluconeogenesis/glycolysis, galactose metabolism, and carbon metabolism. Hub genes were identified, and RT-qPCR results indicated that O3 decreased their transcription levels. Comparative analysis of their human orthologs was conducted using Comparative Toxicogenomics Database (CTD) and DisGeNET databases. These genes are linked to various metabolic diseases, including diabetes, hypoglycemia, and obesity. The trehalose content was reduced in F0 generation flies but increased in F1-F2 generations after O3 exposure. While the trehalase and glucose levels were decreased across F0-F2 generations. TAG synthesis-related genes were significantly upregulated in F0 generation flies but downregulated in F1-F2 generations. The expression patterns of lipolysis-related genes varied among the three generations of flies. Food intake was increased in F0 generation flies but decreased in F1-F2 generations. Moreover, TAG content was significantly elevated in F0 generation flies by O3 exposure, while it was reduced in F2 generation flies. These differential effects of O3 across three generations of flies suggest a metabolic reprogramming aimed at mitigating the damage caused by O3 to flies. The study affirms the viability of employing the Drosophila model to investigate the mechanisms underlying O3-induced glucose and lipid metabolism disorders while emphasizing the importance of studying the long-term health effects of O3 exposure. Moreover, this research highlights the Drosophila model as a viable tool for investigating the multigenerational effects of pollutants, particularly atmospheric pollutants.

Associations between long-term exposure to air pollution, diabetes, and hypertension in metropolitan Iran: an ecologic study

Epidemiological studies on air pollution, diabetes, and hypertension conflict. This study examined air pollution, diabetes, and hypertension in adults in 11 metropolitan areas of Iran (2012-2016). Local environment departments and the Tehran Air Quality Control Company provided air quality data. The VIZIT website and Stepwise Approach to Chronic Disease Risk Factor Surveillance study delivered chronic disease data. Multiple logistic regression and generalized estimating equations evaluated air pollution-related diabetes and hypertension. In Isfahan, Ahvaz, and Tehran, PM2.5 was linked to diabetes. In all cities except Urmia, Yasuj, and Yazd, PM2.5 was statistically related to hypertension. O3 was connected to hypertension in Ahvaz, Tehran, and Shiraz, whereas NO2 was not. BMI and gender predict hypertension and diabetes. Diabetes, SBP, and total cholesterol were correlated. Iran's largest cities' poor air quality may promote diabetes and hypertension. PM2.5 impacts many cities' outcomes. Therefore, politicians and specialists have to control air pollution.

Associations between PM2.5 and O3 exposures and new onset type 2 diabetes in regional and national samples in the United States

BACKGROUND

Exposure to particulate matter ≤2.5 μm in diameter (PM2.5) and ozone (O3) has been linked to numerous harmful health outcomes. While epidemiologic evidence has suggested a positive association with type 2 diabetes (T2D), there is heterogeneity in findings. We evaluated exposures to PM2.5 and O3 across three large samples in the US using a harmonized approach for exposure assignment and covariate adjustment.

METHODS

Data were obtained from the Veterans Administration Diabetes Risk (VADR) cohort (electronic health records [EHRs]), the Reasons for Geographic and Racial Disparities in Stroke (REGARDS) cohort (primary data collection), and the Geisinger health system (EHRs), and reflect the years 2003-2016 (REGARDS) and 2008-2016 (VADR and Geisinger). New onset T2D was ascertained using EHR information on medication orders, laboratory results, and T2D diagnoses (VADR and Geisinger) or report of T2D medication or diagnosis and/or elevated blood glucose levels (REGARDS). Exposure was assigned using pollutant annual averages from the Downscaler model. Models stratified by community type (higher density urban, lower density urban, suburban/small town, or rural census tracts) evaluated likelihood of new onset T2D in each study sample in single- and two-pollutant models of PM2.5 and O3.

RESULTS

In two pollutant models, associations of PM2.5, and new onset T2D were null in the REGARDS cohort except for in suburban/small town community types in models that also adjusted for NSEE, with an odds ratio (95% CI) of 1.51 (1.01, 2.25) per 5 μg/m3 of PM2.5. Results in the Geisinger sample were null. VADR sample results evidenced nonlinear associations for both pollutants; the shape of the association was dependent on community type.

CONCLUSIONS

Associations between PM2.5, O3 and new onset T2D differed across three large study samples in the US. None of the results from any of the three study populations found strong and clear positive associations.

Risk of type 2 diabetes after diagnosed gestational diabetes is enhanced by exposure to PM2.5

BACKGROUND

Air pollution and gestational diabetes mellitus (GDM) are both associated with increased diabetes mellitus (DM) occurrence. However, whether air pollutants modify the effects of GDM on the occurrence of DM has been unknown. This study aims to determine whether the effect of GDM on DM development can be modified by exposure to ambient air pollutants.

METHODS

Women with one singleton birth delivery during 2004-14 according to the Taiwan Birth Certificate Database (TBCD) were included as the study cohort. Those newly diagnosed as having DM 1 year or later after childbirth were identified as DM cases. Controls were selected among women without DM diagnosis during follow-up. Personal residence was geocoded and linked with interpolated concentrations of air pollutants into township levels. Conditional logistic regression was used to determine the odds ratio (OR) of pollutant exposure and GDM, adjusting for age, smoking and meteorological variables.

RESULTS

There were 9846 women who were newly diagnosed as having DM over a mean follow-up period of 10.2 years. We involved them and the 10-fold matching controls involved in our final analysis. The OR (odds ratio) (95% confidence interval, 95% CI) of DM occurrence per interquartile range increased in particulate matter (PM) smaller than or equal to 2.5 µm (PM2.5) and ozone (O3) was 1.31 (1.22-1.41) and 1.20 (1.16-1.25), respectively. The effects of PM exposure on DM development were significantly higher in the GDM group (OR: 2.46, 95% CI: 1.84-3.30) than in the non-GDM group (OR: 1.30, 95% CI: 1.21-1.40).

CONCLUSIONS

Exposure to high levels of PM2.5 and O3 elevates the risk of DM. GDM acted synergistically in DM development with exposure to PM2.5 but not with that to O3.

Long-term air pollution exposure and markers of cardiometabolic health in the National Longitudinal Study of Adolescent to Adult Health (Add Health)

BACKGROUND

Air pollution exposure is associated with cardiovascular morbidity and mortality. Although exposure to air pollution early in life may represent a critical window for development of cardiovascular disease risk factors, few studies have examined associations of long-term air pollution exposure with markers of cardiovascular and metabolic health in young adults.

OBJECTIVES

By combining health data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) with air pollution data from the Fused Air Quality Surface using Downscaling (FAQSD) archive, we: (1) calculated multi-year estimates of exposure to ozone (O3) and particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM2.5) for Add Health participants; and (2) estimated associations between air pollution exposures and multiple markers of cardiometabolic health.

METHODS

Add Health is a nationally representative longitudinal cohort study of over 20,000 adolescents aged 12-19 in the United States (US) in 1994-95 (Wave I). Participants have been followed through adolescence and into adulthood with five in-home interviews. Estimated daily concentrations of O3 and PM2.5 at census tracts were obtained from the FAQSD archive and used to generate tract-level annual averages of O3 and PM2.5 concentrations. We estimated associations between average O3 and PM2.5 exposures from 2002 to 2007 and markers of cardiometabolic health measured at Wave IV (2008-09), including hypertension, hyperlipidemia, body mass index (BMI), diabetes, C-reactive protein, and metabolic syndrome.

RESULTS

The final sample size was 11,259 individual participants. The average age of participants at Wave IV was 28.4 years (range: 24-34 years). In models adjusting for age, race/ethnicity, and sex, long-term O3 exposure (2002-07) was associated with elevated odds of hypertension, with an odds ratio (OR) of 1.015 (95% confidence interval [CI]: 1.011, 1.029); obesity (1.022 [1.004, 1.040]); diabetes (1.032 [1.009,1.054]); and metabolic syndrome (1.028 [1.014, 1.041]); PM2.5 exposure (2002-07) was associated with elevated odds of hypertension (1.022 [1.001, 1.045]).

CONCLUSION

Findings suggest that long-term ambient air pollution exposure, particularly O3 exposure, is associated with cardiometabolic health in early adulthood.

The effect of ambient ozone exposure on three types of diabetes: a meta-analysis

BACKGROUND

Ozone as an air pollutant is gradually becoming a threat to people's health. However, the effect of ozone exposure on risk of developing diabetes, a fast-growing global metabolic disease, remains controversial.

OBJECTIVE

To evaluate the impact of ambient ozone exposure on the incidence rate of type 1, type 2 and gestational diabetes mellitus.

METHOD

We systematically searched PubMed, Web of Science, and Cochrane Library databases before July 9, 2022, to determine relevant literature. Data were extracted after quality evaluation according to the Newcastle Ottawa Scale (NOS) and the agency for healthcare research and quality (AHRQ) standards, and a meta-analysis was used to evaluate the correlation between ozone exposure and type 1 diabetes mellitus (T1D), type 2 diabetes mellitus (T2D), and gestational diabetes mellitus (GDM). The heterogeneity test, sensitivity analysis, and publication bias were performed using Stata 16.0.

RESULTS

Our search identified 667 studies from three databases, 19 of which were included in our analysis after removing duplicate and ineligible studies. Among the remaining studies, three were on T1D, five were on T2D, and eleven were on GDM. The result showed that ozone exposure was positively correlated with T2D [effect size (ES) = 1.06, 95% CI: 1.02, 1.11] and GDM [pooled odds ratio (OR) = 1.01, 95% CI: 1.00, 1.03]. Subgroup analysis demonstrated that ozone exposure in the first trimester of pregnancy might raise the risk of GDM. However, no significant association was observed between ozone exposure and T1D.

CONCLUSION

Long-term exposure to ozone may increase the risk of T2D, and daily ozone exposure during pregnancy was a hazard factor for developing GDM. Decreasing ambient ozone pollution may reduce the burden of both diseases.

Air pollution and the onset of balance problems: The Canadian longitudinal study on aging

PURPOSE

To understand the relationship between ambient air pollution and the onset of balance problems.

DESIGN

Population-based prospective cohort study.

METHODS

Baseline and 3-year follow-up data were used from the Canadian Longitudinal Study on Aging. The Comprehensive Cohort included adults aged 45-85 years old recruited from 11 sites across 7 provinces. Data on air pollution came from the Canadian Urban Environmental Health Research Consortium. Annual mean levels of ozone, fine particulate matter (PM_2.5), and sulfur dioxide for each participant's postal code were estimated from satellite data. Balance was measured at both time points using the one-leg balance test with those who could not stand on one leg for at least 60 s defined as failing the balance test. Our outcome was the new development of failing the balance test at follow-up in those who passed the balance test at baseline. Logistic regression was used.

RESULTS

Of the 12,158 people who could stand for 60 s on one leg at baseline, 18% were unable to do so 3 years later. In single pollutant models, living in an area with higher ozone levels was associated with the 3-year onset of balance problems (odds ratio (OR) = 1.13 per interquartile range of ozone, 95% CI 1.02, 1.24) after adjustment for demographic, lifestyle, and health variables. In a multipollutant model, the association with ozone increased slightly (OR = 1.16, 95% CI 1.04, 1.30). There were no associations with PM_2.5 or sulfur dioxide.

CONCLUSION

Our findings provide longitudinal evidence that higher ozone levels are associated with the odds of developing balance problems over a 3-year period. Further work should attempt to confirm our findings and explore the potential mechanism of action.

Long-term air pollution exposure and diabetes risk in American older adults: A national secondary data-based cohort study

Type 2 diabetes is a major public health concern. Several studies have found an increased diabetes risk associated with long-term air pollution exposure. However, most current studies are limited in their generalizability, exposure assessment, or the ability to differentiate incidence and prevalence cases. We assessed the association between air pollution and first documented diabetes occurrence in a national U.S. cohort of older adults to estimate diabetes risk. We included all Medicare enrollees 65 years and older in the fee-for-service program, part A and part B, in the contiguous United States (2000-2016). Participants were followed annually until the first recorded diabetes diagnosis, end of enrollment, or death (264, 869, 458 person-years). We obtained annual estimates of fine particulate matter (PM2.5), nitrogen dioxide (NO2), and warm-months ozone (O3) exposures from highly spatiotemporally resolved prediction models. We assessed the simultaneous effects of the pollutants on diabetes risk using survival analyses. We repeated the models in cohorts restricted to ZIP codes with air pollution levels not exceeding the national ambient air quality standards (NAAQS) during the study period. We identified 10, 024, 879 diabetes cases of 41, 780, 637 people (3.8% of person-years). The hazard ratio (HR) for first diabetes occurrence was 1.074 (95% CI 1.058; 1.089) for 5 μg/m3 increase in PM2.5, 1.055 (95% CI 1.050; 1.060) for 5 ppb increase in NO2, and 0.999 (95% CI 0.993; 1.004) for 5 ppb increase in O3. Both for NO2 and PM2.5 there was evidence of non-linear exposure-response curves with stronger associations at lower levels (NO2 ≤ 36 ppb, PM2.5 ≤ 8.2 μg/m3). Furthermore, associations remained in the restricted low-level cohorts. The O3-diabetes exposure-response relationship differed greatly between models and require further investigation. In conclusion, exposures to PM2.5 and NO2 are associated with increased diabetes risk, even when restricting the exposure to levels below the NAAQS set by the U.S. EPA.

Diabetes and climate change

It is widely accepted that climate change is the biggest threat to human health. The pandemic of diabetes is also a major threat to human health, especially in rapidly developing nations. Climate change and diabetes appear to have common global vectors, including increased urbanisation, increased use of transportation, and production and ingestion of ultra-processed foods. People with diabetes appear to be at higher risk of threats to health from climate change, including effects from extreme heat or extreme cold, and natural disasters. Solutions to climate change offer some benefits for the prevention of diabetes and diabetes-related complications. Moving towards lower carbon economies is likely to help reduce reliance on intensive agriculture, reduce physical inactivity, reduce air pollution and enhance quality of life. It may enable a reduction in the prevalence of diabetes and reduced morbidity from the condition.

Long-term air pollution exposure and diabetes risk in American older adults: A national secondary data-based cohort study

Type 2 diabetes is a major public health concern. Several studies have found an increased diabetes risk associated with long-term air pollution exposure. However, most current studies are limited in their generalizability, exposure assessment, or the ability to differentiate incidence and prevalence cases. We assessed the association between air pollution and first documented diabetes occurrence in a national U.S. cohort of older adults to estimate diabetes risk. We included all Medicare enrollees 65 years and older in the fee-for-service program, part A and part B, in the contiguous United States (2000-2016). Participants were followed annually until the first recorded diabetes diagnosis, end of enrollment, or death (264, 869, 458 person-years). We obtained annual estimates of fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), and warm-months ozone (O₃) exposures from highly spatiotemporally resolved prediction models. We assessed the simultaneous effects of the pollutants on diabetes risk using survival analyses. We repeated the models in cohorts restricted to ZIP codes with air pollution levels not exceeding the national ambient air quality standards (NAAQS) during the study period. We identified 10, 024, 879 diabetes cases of 41, 780, 637 people (3.8% of person-years). The hazard ratio (HR) for first diabetes occurrence was 1.074 (95% CI 1.058; 1.089) for 5 μg/m³ increase in PM_2.5, 1.055 (95% CI 1.050; 1.060) for 5 ppb increase in NO₂, and 0.999 (95% CI 0.993; 1.004) for 5 ppb increase in O₃. Both for NO₂ and PM_2.5 there was evidence of non-linear exposure-response curves with stronger associations at lower levels (NO₂ ≤ 36 ppb, PM_2.5 ≤ 8.2 μg/m³). Furthermore, associations remained in the restricted low-level cohorts. The O₃-diabetes exposure-response relationship differed greatly between models and require further investigation. In conclusion, exposures to PM_2.5 and NO₂ are associated with increased diabetes risk, even when restricting the exposure to levels below the NAAQS set by the U.S. EPA.

Associations of ozone exposure with gestational diabetes mellitus and glucose homeostasis: Evidence from a birth cohort in Shanghai, China

BACKGROUND

Associations between individual exposure to ozone (O₃) and gestational diabetes mellitus (GDM) have rarely been investigated, and critical windows of O₃ exposure for GDM have not been identified.

OBJECTIVES

We aimed to explore the associations of gestational O₃ exposure with GDM and glucose homeostasis as well as to identify the potential critical windows.

METHODS

A total of 7834 pregnant women were included. Individual O₃ exposure concentrations were evaluated using a high temporal-spatial resolution model. Each participant underwent an oral glucose tolerance test (OGTT) to screen for GDM between 24 and 28 gestational weeks. Multiple logistic and multiple linear regression models were used to estimate the associations of O₃ with GDM risks and with blood glucose levels of OGTT, respectively. Distributed lag nonlinear models (DLNMs) were used to estimate the critical windows of O₃ exposure for GDM.

RESULTS

Nearly 13.29 % of participants developed GDM. After controlling for covariates, we observed increased GDM risks per IQR increment of O₃ exposure in the first trimester (OR = 1.738, 95 % CI: 1.002-3.016) and the first two trimesters (OR = 1.576, 95 % CI: 1.005-2.473). Gestational O₃ exposure was positively associated with increased fasting blood glucose (the first trimester: β = 2.964, 95 % CI: 1.529-4.398; the first two trimesters: β = 1.620, 95 % CI: 0.436-2.804) and 2 h blood glucose (the first trimester: β = 6.569, 95 % CI: 1.775-11.363; the first two trimesters: β = 6.839, 95 % CI: 2.896-10.782). We also observed a concentration-response relationship of gestational O₃ exposure with GDM risk, as well as fasting and 2 h blood glucose levels. Additionally, 5-10 gestational weeks was identified as a critical window of O₃ exposure for GDM development.

CONCLUSION

In summary, we found that gestational O₃ exposure disrupts glucose homeostasis and increases the risk of GDM in pregnant women. Furthermore, 5-10 gestational weeks could be a critical window for the effects of O₃ exposure on GDM.

Is city-level travel time by car associated with individual obesity or diabetes in Latin American cities? Evidence from 178 cities in the SALURBAL project

There is growing evidence that longer travel time by private car poses physical and mental risks. Individual-level obesity and diabetes, two of the main public health challenges in low- and middle-income contexts, could be associated to city-level travel times by car. We used individual obesity and diabetes data from national health surveys from individuals in 178 Latin American cities, compiled and harmonized by the SALURBAL project. We calculated city-level travel times by car using the Google Maps Distance Matrix API. We estimated associations between peak hour city-level travel time by car and obesity and diabetes using multilevel logistic regression models, while adjusting for individual characteristics and other city-level covariates. In our study we did not observe a relationship between city-level peak-hour travel time by car and individual obesity and diabetes, as reported in previous research for individual time spent in vehicles in high-income settings. Our results suggest that this relationship may be more complex in Latin America compared to other settings, especially considering that cities in the region are characterized by high degrees of population density and compactness and by a higher prevalence of walking and public transportation use.

Physical activity attenuated the association of ambient ozone with type 2 diabetes mellitus and fasting blood glucose among rural Chinese population

The association of ozone with type 2 diabetes mellitus (T2DM) is uncertain. Moreover, the moderating effect of physical activity on this association is largely unknown. This study aims to evaluate the independent and combined effects of ozone and physical activity on T2DM and fasting blood glucose (FBG) in a Chinese rural adult population. A total of 39,192 participants were enrolled in the Henan Rural Cohort Study. Individual ozone exposure was assessed by using a satellite-based random forest model. The logistic regression and generalized linear models were used to evaluate the associations of ozone and physical activity with T2DM and FBG, respectively. Interaction plots were used to visualize the interaction effects of ozone and physical activity on T2DM or FBG. An interquartile range (IQR) increase in ozone exposure concentration was related to a 53.3% (odds ratio (OR),1.533; 95% confidence interval (CI), 1.426, 1.648) increase in odds of T2DM and a 0.292 mmol/L (95%CI, 0.263, 0.321) higher FBG level, respectively. The effects of ozone on T2DM and FBG generally decreased as physical activity levels increased. Negative additive interactions between ozone and physical activity on T2DM risk were observed (relative excess risk due to interaction (RERI), -0.261; 95%CI, -0.473, -0.048; attributable proportion due to interaction (AP), -0.203; 95%CI, -0.380, -0.027; synergy index (S), 0.520; 95%CI, 0.299, 0.904). The larger effects of ozone were observed among elderly and men on T2DM and FBG than young and women. Long-term exposure to ozone was associated with higher odds of T2DM and higher FBG levels, and these associations might be attenuated by increasing physical activity levels. In addition, there was a negative additive interaction (antagonistic effect) between ozone exposure and physical activity level on T2DM risk, suggesting that physical activity might be an effective method to reduce the burden of T2DM attributed to ozone exposure. Trail registration: The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (registration number: ChiCTR-OOC-15006699). Date of registration: 06 July 2015, http://www.chictr.org.cn/showproj.aspx?proj=11375.

Spatiotemporal variation of ozone pollution and health effects in China

With the rapid urbanization and industrialization in China, ozone pollution has become increasingly serious and poses a greater threat to human health. In this study, the spatiotemporal distribution of ozone pollution in China's cities and urban agglomerations from 2015 to 2019 was analyzed. The health effects and health economic costs of ozone pollution in China were estimated by applying the environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) model. The results are as follows: (1) ozone pollution was more serious in Chinese urban agglomerations from 2015 to 2019; (2) the hot spots of ozone concentration mainly distributed in the North China Plain, expanding from north to south; the cold spots decreased year by year and were located in the northeast, northwest, and southwest of China, shifting from northwest to southwest; (3) the seasonal average of ozone concentration in China was the highest in summer, followed by spring and autumn, and the lowest in winter; (4) the number of all-cause premature deaths of ozone pollution in China increased slowly from 2015 to 2019, and the average of urban agglomerations was significantly higher than cities, with similar spatial distribution characteristics as ozone concentration; (5) the health economic costs of ozone pollution from 2015 to 2019 slowly expanded to surrounding cities with Beijing, Shanghai, Xi'an, and Chongqing as the centers of high values, while the low value areas decreased year by year and were mainly concentrated in southwest and northeast China. The health economic costs of ozone pollution at urban agglomerations scale were higher in the eastern coastal regions and lower in the northwest inland regions. Thus, this study presents policy recommendations to provide decision-making reference for realizing the inter-regional prevention and control of ozone pollution.

Long-term exposure to ozone and diabetes incidence: A longitudinal cohort study in China

BACKGROUND

Ozone (O₃) has become a prominent air pollutant problem as other pollutants concentrations have decreased obviously since China published Air Pollution Action Plan Pollution Prevention Action Plan in 2013. Few studies examined the association between O₃ and diabetes especially in developing countries. This study was designed to investigate the above topic in China.

METHODS

We conducted a prospective cohort study based on a nationwide survey of 13,548 adults from China Health and Retirement Longitudinal Study. City-level exposure to ozone for each participant was matched through ChinaHighO₃ dataset. Time-varying cox proportional hazard regression model was applied to determine the association. Stratification analyses were conducted to explore potential effect modification.

RESULTS

The annual mean concentration of O₃ was 86.6 μg/m³. A 10 μg/m³ increase in 1-year average O₃ concentration was associated with 5.7% (95% CI: 1.004-1.114) relative increment in hazards ratio of diabetes incidence in the fully adjusted model. Results stayed stable when controlling for physical activity, PM_2.5 and mean temperature.

CONCLUSIONS

Our findings provided initial support for a positive and robust association between long-term exposure to O₃ and diabetes incidence in a developing country. More scientific and social attention should be attached to the ozone-induced risks of diabetes occurrence.

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.

Ozone Exposure, Outdoor Physical Activity, and Incident Type 2 Diabetes in the SALSA Cohort of Older Mexican Americans

BACKGROUND

Type 2 diabetes is a leading contributor to the global burden of morbidity and mortality. Ozone (O3) exposure has previously been linked to diabetes.

OBJECTIVE

We studied the impact of O3 exposure on incident diabetes risk in elderly Mexican Americans and investigated whether outdoor physical activity modifies the association.

METHODS

We selected 1,090 Mexican American participants from the Sacramento Area Latino Study on Aging conducted from 1998 to 2007. Ambient O3 exposure levels were modeled with a land-use regression built with saturation monitoring data collected at 49 sites across the Sacramento metropolitan area. Using Cox proportional hazard models, we estimated the risk of developing incident diabetes based on average O3 exposure modeled for 5-y prior to incident diabetes diagnosis or last follow-up. Further, we estimated outdoor leisure-time physical activity at baseline and investigated whether higher vs. lower levels modified the association between O3 exposure and diabetes.

RESULTS

In total, 186 incident diabetes cases were identified during 10-y follow-up. Higher levels of physical activity were negatively associated with incident diabetes [hazard ratio (HR)=0.64 (95% CI: 0.43, 0.95)]. The estimated HRs for incident diabetes was 1.13 (95% CI: 1.00, 1.28) per 10-ppb increment of 5-y average O3 exposure; also, this association was stronger among those physically active outdoors [HR=1.52 (95% CI: 1.21, 1.90)], and close to null for those reporting lower levels of outdoor activity [HR=1.04 (95% CI: 0.90, 1.20), pinteraction=0.01].

CONCLUSIONS

Our findings suggest that ambient O3 exposure contributes to the development of type 2 diabetes, particularly among those with higher levels of leisure-time outdoor physical activity. Policies and strategies are needed to reduce O3 exposure to guarantee that the health benefits of physical activity are not diminished by higher levels of O3 pollution in susceptible populations such as older Hispanics. https://doi.org/10.1289/EHP8620.

A prospective cohort study of ambient air pollution exposure and risk of uterine leiomyomata

STUDY QUESTION

To what extent are ambient concentrations of particulate matter <2.5 microns (PM2.5), nitrogen dioxide (NO2) and ozone (O3) associated with risk of self-reported physician-diagnosed uterine leiomyomata (UL)?

SUMMARY ANSWER

In this large prospective cohort study of Black women, ambient concentrations of O3, but not PM2.5 or NO2, were associated with increased risk of UL.

WHAT IS KNOWN ALREADY

UL are benign tumors of the myometrium that are the leading cause of gynecologic inpatient care among reproductive-aged women. Black women are clinically diagnosed at two to three times the rate of white women and tend to exhibit earlier onset and more severe disease. Two epidemiologic studies have found positive associations between air pollution exposure and UL risk, but neither included large numbers of Black women.

STUDY DESIGN, SIZE, DURATION

We conducted a prospective cohort study of 21 998 premenopausal Black women residing in 56 US metropolitan areas from 1997 to 2011.

PARTICIPANTS/MATERIAL, SETTING, METHODS

Women reported incident UL diagnosis and method of confirmation (i.e. ultrasound, surgery) on biennial follow-up questionnaires. We modeled annual residential concentrations of PM2.5, NO2 and O3 throughout the study period. We used Cox proportional hazards regression models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for a one-interquartile range (IQR) increase in air pollutant concentrations, adjusting for confounders and co-pollutants.

MAIN RESULTS AND THE ROLE OF CHANCE

During 196 685 person-years of follow-up, 6238 participants (28.4%) reported physician-diagnosed UL confirmed by ultrasound or surgery. Although concentrations of PM2.5 and NO2 were not appreciably associated with UL (HRs for a one-IQR increase: 1.01 (95% CI: 0.93, 1.10) and 1.05 (95% CI: 0.95, 1.16), respectively), O3 concentrations were associated with increased UL risk (HR for a one-IQR increase: 1.19, 95% CI: 1.07, 1.32). The association was stronger among women age <35 years (HR: 1.26, 95% CI: 0.98, 1.62) and parous women (HR: 1.28, 95% CI: 1.11, 1.48).

LIMITATIONS, REASONS FOR CAUTION

Our measurement of air pollution is subject to misclassification, as monitoring data are not equally spatially distributed and we did not account for time-activity patterns. Our outcome measure was based on self-report of a physician diagnosis, likely resulting in under-ascertainment of UL. Although we controlled for several individual- and neighborhood-level confounding variables, residual confounding remains a possibility.

WIDER IMPLICATIONS OF THE FINDINGS

Inequitable burden of air pollution exposure has important implications for racial health disparities, and may be related to disparities in UL. Our results emphasize the need for additional research focused on environmental causes of UL.

STUDY FUNDING/COMPETING INTEREST(S)

This research was funded by the National Cancer Institute (U01-CAA164974) and the National Institute of Environmental Health Sciences (R01-ES019573). L.A.W. is a fibroid consultant for AbbVie, Inc. and accepts in-kind donations from Swiss Precision Diagnostics, Sandstone Diagnostics, FertilityFriend.com and Kindara.com for primary data collection in Pregnancy Study Online (PRESTO). M.J. declares consultancy fees from the Health Effects Institute (as a member of the review committee). The remaining authors declare they have no actual or potential competing financial interests.

TRIAL REGISTRATION NUMBER

N/A.

Associations between air pollution indicators and prevalent and incident diabetes in an African American cohort, the Jackson Heart Study

Background

Diabetes is especially prevalent among African Americans. Prior studies suggest that long-term exposure to ambient air pollution may be associated with greater incidence of diabetes, but results remain heterogeneous. Few studies have included large numbers of African Americans.

Methods

We assessed diabetes status and concentrations of 1- and 3-year fine particulate matter (PM_2.5) and ozone (O₃) among African American participants of the Jackson Heart Study at visits 1 (2000-2004, N = 5128) and 2 (2005-2008, N = 2839). We used mixed-effect modified Poisson regression to estimate risk ratios (RRs) and 95% confidence intervals (CIs) of incidence of diabetes by visit 2 and prevalence ratios (PRs) of the association between air pollution exposure and prevalent diabetes at visits 1 and 2. We adjusted for potential confounding by patient characteristics, as well as inverse probability weights of diabetes at visit 2, accounting for clustering by census tract.

Results

We observed associations between incident diabetes and interquartile range increase in 1-year O₃ (RR 1.34, 95% CI = 1.11, 1.61) and 3-year O₃ (RR 0.88, 95% CI = 0.76, 1.02). We observed associations between prevalent diabetes and 1-year PM_2.5 (PR 1.08, 95% CI = 1.00, 1.17), 1-year O₃ (PR 1.18, 95% CI = 1.10, 1.27), and 3-year O₃ (PR 0.95, 95% CI = 0.90, 1.01) at visit 2.

Conclusions

Our results provide some evidence of positive associations between indicators of long-term PM_2.5 and O₃ exposure and diabetes. This study is particularly relevant to African Americans, who have higher prevalence of diabetes but relatively few studies of environmental pollution risk factors.

Long-term exposure to ozone and sulfur dioxide increases the incidence of type 2 diabetes mellitus among aged 30 to 50 adult population

AIMS/HYPOTHESIS

Worldwide, the information regarding the associations between long-term exposure to ozone (O₃) and sulfur dioxide (SO₂) and the development of type 2 diabetes remains scarce, especially in Asia. This study aimed to investigate the long-term effects of exposure to ambient O₃ and SO₂ on the incidence of type 2 diabetes with consideration of other air pollutants in Taiwanese adults aged 30 to 50 years.

METHODS

A total of 6,426,802 non-diabetic participants aged between 30 and 50 years old were obtained from the National Health Insurance Research Database between 2005 and 2016. Incident type 2 diabetes was the main diagnosis at medical visits. Air quality data were provided by the Taiwan Environmental Protection Administration. The air pollutant concentrations for each participant were estimated using the ordinary kriging method to interpolate daily concentrations of O₃, SO₂, carbon monoxide (CO), nitrogen dioxide (NO₂), suspended fine particles (with an aerodynamic diameter less than 2.5 μm; PM_2.5), and suspended particles (with an aerodynamic diameter less than 10 μm; PM₁₀) in residential districts across Taiwan. Six-year average concentrations of pollutants were calculated from January 1, 2005 to December 31, 2010, and data were categorized into quartiles. We performed Cox regression models to analyze the long-term effects of exposure to O₃ and SO₂ on the incidence of type 2 diabetes.

RESULTS

The hazard ratio (HR) for the incidence of diabetes per each interquartile range (IQR) increase in ozone exposure (3.30 ppb) was 1.058 (95% confidence interval (CI): 1.053, 1.064) and 1.011 (95% CI: 1.007, 1.015) for SO₂ exposure (1.77 ppb) after adjusting for age, sex, socioeconomic status, urbanization level, temperature, humidity, and chronic comorbidities (Model 3). Furthermore, for every 3.30 ppb increase of O₃, the HR for incident type 2 diabetes was 1.093 (95% CI: 1.087, 1.100) after controlling factors shown in Model 3 plus SO₂ and PM_2.5. On the other hand, for every 1.77 ppb increase of SO₂, the HR for incident type 2 diabetes was 1.073 (95% CI: 1.068, 1.079) after controlling factors shown in Model 3 plus NO₂ and PM_2.5.

CONCLUSIONS

Long-term exposure to ambient O₃ and SO₂ was associated with a higher risk of developing type 2 diabetes for Taiwanese population. Exposure to O₃ and SO₂ may play a role in the adult early-onset type 2 diabetes.

Air pollution and breast cancer risk in the Black Women's Health Study

BACKGROUND

Air pollution contains numerous carcinogens and endocrine disruptors which may be relevant for breast cancer. Previous research has predominantly been conducted in White women; however, Black women may have higher air pollution exposure due to geographic and residential factors.

OBJECTIVE

We evaluated the association between air pollution and breast cancer risk in a large prospective population of Black women.

METHODS

We estimated annual average ambient levels of particulate matter <2.5 μm (PM_2.5), nitrogen dioxide (NO₂) and ozone (O₃) at the 1995 residence of 41,317 participants in the Black Women's Health Study who resided in 56 metropolitan areas across the United States. Cox proportional hazards regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for an interquartile range (IQR) increase in each pollutant. We evaluated whether the association varied by menopausal status, estrogen receptor (ER) status of the tumor and geographic region of residence.

RESULTS

With follow-up through 2015 (mean = 18.3 years), 2146 incident cases of breast cancer were confirmed. Higher exposure to NO₂ or O₃ was not associated with a higher risk of breast cancer. For PM_2.5, although we observed no association overall, there was evidence of modification by geographic region for both ER- (p for heterogeneity = 0.01) and premenopausal breast cancer (p for heterogeneity = 0.01). Among women living in the Midwest, an IQR increase in PM_2.5 (2.87 μg/m³), was associated with a higher risk of ER- (HR = 1.53, 95% CI: 1.07-2.19) and premenopausal breast cancer (HR = 1.32, 95% CI: 1.03-1.71). In contrast, among women living in the South, PM_2.5 was inversely associated with both ER- (HR = 0.74, 95% CI: 0.56-0.97) and premenopausal breast cancer risk (HR = 0.75, 95% CI: 0.62-0.91).

DISCUSSION

Overall, we observed no association between air pollution and increased breast cancer risk among Black women, except perhaps among women living in the Midwestern US.

Metabolic dysfunction modifies the influence of traffic-related air pollution and noise exposure on late-life dementia and cognitive impairment: A cohort study of older Mexican-Americans

Supplemental Digital Content is available in the text.

Cognitive impairment has been linked to traffic-related air pollution and noise exposure as well as to metabolic syndrome or some of its individual components. Here, we investigate whether the presence of metabolic dysfunction modifies associations between air pollution or noise exposures and incident dementia or cognitive impairment without dementia (CIND).

Metabolic dysfunction modifies the influence of traffic-related air pollution and noise exposure on late-life dementia and cognitive impairment: A cohort study of older Mexican-Americans

Cognitive impairment has been linked to traffic-related air pollution and noise exposure as well as to metabolic syndrome or some of its individual components. Here, we investigate whether the presence of metabolic dysfunction modifies associations between air pollution or noise exposures and incident dementia or cognitive impairment without dementia (CIND).

METHODS

For 1,612 elderly Mexican-American participants of the Sacramento Area Latino Study on Aging (SALSA) followed for up to 10 years, we estimated residential-based local traffic-related exposures relying on the California Line Source Dispersion Model version 4 (CALINE4) for nitrogen oxides (NOx) and the SoundPLAN software package (Version 8.0; NAVCON, Fullerton, CA) that implements the Federal Highway Administration Traffic Noise Model (TNM) for noise, respectively. We used Cox proportional hazard models to estimate the joint effects of NOx or noise exposures and obesity, hyperglycemia, or low high-density lipoprotein (HDL) cholesterol.

RESULTS

The risk of developing dementia/CIND among participants with hyperglycemia who also were exposed to high levels of NOx (≥3.44 parts per billion [ppb] [75th percentile]) or noise (≥65 dB) was 2.4 (1.4, 4.0) and 2.2 (1.7, 3.9), respectively. For participants with low HDL-cholesterol, the estimated hazard ratios for dementia/CIND were 2.5 (1.4, 4.3) and 1.8 (1.0, 3.0) for those also exposed to high levels of NOx (≥3.44 ppb) or noise (≥65 dB), respectively, compared with those without metabolic dysfunction exposed to low traffic-related air pollution or noise levels.

CONCLUSIONS

Exposure to traffic-related air pollution or noise most strongly increases the risk of dementia/CIND among older Mexican-Americans living in California who also exhibit hyperglycemia or low HDL-cholesterol.

The Effects of Social, Personal, and Behavioral Risk Factors and PM2.5 on Cardio-Metabolic Disparities in a Cohort of Community Health Center Patients

(1) Background: Cardio-metabolic diseases (CMD), including cardiovascular disease, stroke, and diabetes, have numerous common individual and environmental risk factors. Yet, few studies to date have considered how these multiple risk factors together affect CMD disparities between Blacks and Whites. (2) Methods: We linked daily fine particulate matter (PM2.5) measures with survey responses of participants in the Southern Community Cohort Study (SCCS). Generalized linear mixed modeling (GLMM) was used to estimate the relationship between CMD risk and social-demographic characteristics, behavioral and personal risk factors, and exposure levels of PM2.5. (3) Results: The study resulted in four key findings: (1) PM2.5 concentration level was significantly associated with reported CMD, with risk rising by 2.6% for each µg/m3 increase in PM2.5; (2) race did not predict CMD risk when clinical, lifestyle, and environmental risk factors were accounted for; (3) a significant variation of CMD risk was found among participants across states; and (4) multiple personal, clinical, and social-demographic and environmental risk factors played a role in predicting CMD occurrence. (4) Conclusions: Disparities in CMD risk among low social status populations reflect the complex interactions of exposures and cumulative risks for CMD contributed by different personal and environmental factors from natural, built, and social environments.

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

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

Majid NL, Abd. Hamid HA, Rodzlan Hasani WS, Mohd Yussoff MFB, Aris HTB, Ab. Rahman EB, M. Rashid ZB. Association between long-term exposure to ambient air pollution and prevalence of diabetes mellitus among Malaysian adults

BACKGROUND

Malaysia has the highest rate of diabetes mellitus (DM) in the Southeast Asian region, and has ongoing air pollution and periodic haze exposure.

METHODS

Diabetes data were derived from the Malaysian National Health and Morbidity Surveys conducted in 2006, 2011 and 2015. The air pollution data (NOx, NO2, SO2, O3 and PM10) were obtained from the Department of Environment Malaysia. Using multiple logistic and linear regression models, the association between long-term exposure to these pollutants and prevalence of diabetes among Malaysian adults was evaluated.

RESULTS

The PM10 concentration decreased from 2006 to 2014, followed by an increase in 2015. Levels of NOx decreased while O3 increased annually. The air pollutant levels based on individual modelled air pollution exposure as measured by the nearest monitoring station were higher than the annual averages of the five pollutants present in the ambient air. The prevalence of overall diabetes increased from 11.4% in 2006 to 21.2% in 2015. The prevalence of known diabetes, underdiagnosed diabetes, overweight and obesity also increased over these years. There were significant positive effect estimates of known diabetes at 1.125 (95% CI, 1.042, 1.213) for PM10, 1.553 (95% CI, 1.328, 1.816) for O3, 1.271 (95% CI, 1.088, 1.486) for SO2, 1.124 (95% CI, 1.048, 1.207) for NO2, and 1.087 (95% CI, 1.024, 1.153) for NOx for NHMS 2006. The adjusted annual average levels of PM10 [1.187 (95% CI, 1.088, 1.294)], O3 [1.701 (95% CI, 1.387, 2.086)], NO2 [1.120 (95% CI, 1.026, 1.222)] and NOx [1.110 (95% CI, 1.028, 1.199)] increased significantly from NHMS 2006 to NHMS 2011 for overall diabetes. This was followed by a significant decreasing trend from NHMS 2011 to 2015 [0.911 for NO2, and 0.910 for NOx].

CONCLUSION

The findings of this study suggest that long-term exposure to O3 is an important associated factor of underdiagnosed DM risk in Malaysia. PM10, NO2 and NOx may have mixed effect estimates towards the risk of DM, and their roles should be further investigated with other interaction models. Policy and intervention measures should be taken to reduce air pollution in Malaysia.

Multicenter Ozone Study in oldEr Subjects (MOSES): Part 2. Effects of Personal and Ambient Concentrations of Ozone and Other Pollutants on Cardiovascular and Pulmonary Function

INTRODUCTION

The Multicenter Ozone Study of oldEr Subjects (MOSES) was a multi-center study evaluating whether short-term controlled exposure of older, healthy individuals to low levels of ozone (O3) induced acute changes in cardiovascular biomarkers. In MOSES Part 1 (MOSES 1), controlled O3 exposure caused concentration-related reductions in lung function with evidence of airway inflammation and injury, but without convincing evidence of effects on cardiovascular function. However, subjects' prior exposures to indoor and outdoor air pollution in the few hours and days before each MOSES controlled O3 exposure may have independently affected the study biomarkers and/or modified biomarker responses to the MOSES controlled O3 exposures.

METHODS

MOSES 1 was conducted at three clinical centers (University of California San Francisco, University of North Carolina, and University of Rochester Medical Center) and included healthy volunteers 55 to 70 years of age. Consented participants who successfully completed the screening and training sessions were enrolled in the study. All three clinical centers adhered to common standard operating procedures and used common tracking and data forms. Each subject was scheduled to participate in a total of 11 visits: screening visit, training visit, and three sets of exposure visits consisting of the pre-exposure day, the exposure day, and the post-exposure day. After completing the pre-exposure day, subjects spent the night in a nearby hotel. On exposure days, the subjects were exposed for 3 hours in random order to 0 ppb O3 (clean air), 70 ppb O3, and 120 ppm O3. During the exposure period the subjects alternated between 15 minutes of moderate exercise and 15 minutes of rest. A suite of cardiovascular and pulmonary endpoints was measured on the day before, the day of, and up to 22 hours after each exposure.

In MOSES Part 2 (MOSES 2), we used a longitudinal panel study design, cardiopulmonary biomarker data from MOSES 1, passive cumulative personal exposure samples (PES) of O3 and nitrogen dioxide (NO2) in the 72 hours before the pre-exposure visit, and hourly ambient air pollution and weather measurements in the 96 hours before the pre-exposure visit. We used mixed-effects linear regression and evaluated whether PES O3 and NO2 and these ambient pollutant concentrations in the 96 hours before the pre-exposure visit confounded the MOSES 1 controlled O3 exposure effects on the pre- to post-exposure biomarker changes (Aim 1), whether they modified these pre- to post-exposure biomarker responses to the controlled O3 exposures (Aim 2), whether they were associated with changes in biomarkers measured at the pre-exposure visit or morning of the exposure session (Aim 3), and whether they were associated with differences in the pre- to post-exposure biomarker changes independently of the controlled O3 exposures (Aim 4).

RESULTS

Ambient pollutant concentrations at each site were low and were regularly below the National Ambient Air Quality Standard levels. In Aim 1, the controlled O3 exposure effects on the pre- to post-exposure biomarker differences were little changed when PES or ambient pollutant concentrations in the previous 96 hours were included in the model, suggesting these were not confounders of the controlled O3 exposure/biomarker difference associations. In Aim 2, effects of MOSES controlled O3 exposures on forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were modified by ambient NO2 and carbon monoxide (CO), and PES NO2, with reductions in FEV1 and FVC observed only when these concentrations were "Medium" or "High" in the 72 hours before the pre-exposure visit. There was no such effect modification of the effect of controlled O3 exposure on any other cardiopulmonary biomarker.

As hypothesized for Aim 3, increased ambient O3 concentrations were associated with decreased pre-exposure heart rate variability (HRV). For example, high frequency (HF) HRV decreased in association with increased ambient O3 concentrations in the 96 hours before the pre-exposure visit (-0.460 ln[ms2]; 95% CI, -0.743 to -0.177 for each 10.35-ppb increase in O3; P = 0.002). However, in Aim 4 these increases in ambient O3 were also associated with increases in HF and low frequency (LF) HRV from pre- to post-exposure, likely reflecting a "recovery" of HRV during the MOSES O3 exposure sessions. Similar patterns across Aims 3 and 4 were observed for LF (the other primary HRV marker), and standard deviation of normal-to-normal sinus beat intervals (SDNN) and root mean square of successive differences in normal-to-normal sinus beat intervals (RMSSD) (secondary HRV markers).

Similar Aim 3 and Aim 4 patterns were observed for FEV1 and FVC in association with increases in ambient PM with an aerodynamic diameter ≤ 2.5 μm (PM2.5), CO, and NO2 in the 96 hours before the pre-exposure visit. For Aim 3, small decreases in pre-exposure FEV1 were significantly associated with interquartile range (IQR) increases in PM2.5 concentrations in the 1 hour before the pre-exposure visit (-0.022 L; 95% CI, -0.037 to -0.006; P = 0.007), CO in the 3 hours before the pre-exposure visit (-0.046 L; 95% CI, -0.076 to -0.016; P = 0.003), and NO2 in the 72 hours before the pre-exposure visit (-0.030 L; 95% CI, -0.052 to -0.008; P = 0.007). However, FEV1 was not associated with ambient O3 or sulfur dioxide (SO2), or PES O3 or NO2 (Aim 3). For Aim 4, increased FEV1 across the exposure session (post-exposure minus pre-exposure) was marginally significantly associated with each 4.1-ppb increase in PES O3 concentration (0.010 L; 95% CI, 0.004 to 0.026; P = 0.010), as well as ambient PM2.5 and CO at all lag times. FVC showed similar associations, with patterns of decreased pre-exposure FVC associated with increased PM2.5, CO, and NO2 at most lag times, and increased FVC across the exposure session also associated with increased concentrations of the same pollutants, reflecting a similar recovery. However, increased pollutant concentrations were not associated with adverse changes in pre-exposure levels or pre- to post-exposure changes in biomarkers of cardiac repolarization, ST segment, vascular function, nitrotyrosine as a measure of oxidative stress, prothrombotic state, systemic inflammation, lung injury, or sputum polymorphonuclear leukocyte (PMN) percentage as a measure of airway inflammation.

CONCLUSIONS

Our previous MOSES 1 findings of controlled O3 exposure effects on pulmonary function, but not on any cardiovascular biomarker, were not confounded by ambient or personal O3 or other pollutant exposures in the 96 and 72 hours before the pre-exposure visit. Further, these MOSES 1 O3 effects were generally not modified, blunted, or lessened by these same ambient and personal pollutant exposures. However, the reductions in markers of pulmonary function by the MOSES 1 controlled O3 exposure were modified by ambient NO2 and CO, and PES NO2, with reductions observed only when these pollutant concentrations were elevated in the few hours and days before the pre-exposure visit. Increased ambient O3 concentrations were associated with reduced HRV, with "recovery" during exposure visits. Increased ambient PM2.5, NO2, and CO were associated with reduced pulmonary function, independent of the MOSES-controlled O3 exposures. Increased pollutant concentrations were not associated with pre-exposure or pre- to post-exposure changes in other cardiopulmonary biomarkers. Future controlled exposure studies should consider the effect of ambient pollutants on pre-exposure biomarker levels and whether ambient pollutants modify any health response to a controlled pollutant exposure.

Ambient air pollution and diabetes: A systematic review and meta-analysis

BACKGROUND

Air pollutants are suggested to be related to type 2 diabetes (T2D). Since several high quality papers on air pollutants and T2D have been published beyond the last reviews, an extended systematic review is highly warranted. We review epidemiological studies to quantify the association between air pollutants and T2D, and to answer if diabetes patients are more vulnerable to air pollutants.

METHODS

We systematically reviewed the databases of PubMed and Web of Science based on the guidelines of the Preferred Reporting Items for Systematic review and Meta-analysis (PRISMA). We calculated odds ratios (OR) or hazard ratios (HR) and their 95% confidence intervals (CI) to assess the strength of the associations between air pollutants [e.g., particulate matter with diameter ≤ 2.5 μm (PM_2.5), particulate matter with diameter ≤ 10 μm (PM₁₀), and nitrogen dioxide (NO₂)] and T2D. We evaluated the quality and risk of bias of the included studies and graded the credibility of the pooled evidence using several recommended tools. We also performed sensitivity analysis, meta-regression analysis, and publication bias test.

RESULTS

Out of 716 articles identified, 86 were used for this review and meta-analysis. Meta-analyses showed significant associations of PM_2.5 with T2D incidence (11 studies; HR = 1.10, 95% CI = 1.04-1.17 per 10 μg/m³ increment; I² = 74.4%) and prevalence (11 studies; OR = 1.08; 95% CI = 1.04-1.12 per 10 μg/m³ increment; I² = 84.3%), of PM₁₀ with T2D prevalence (6 studies; OR = 1.10; 95% CI = 1.03-1.17 per 10 μg/m³ increment; I² = 89.5%) and incidence (6 studies; HR = 1.11; 95% CI = 1.00-1.22 per μg/m³ increment; I² = 70.6%), and of NO₂ with T2D prevalence (11 studies; OR = 1.07; 95% CI = 1.04-1.11 per 10 μg/m³ increment; I² = 91.1%). The majority of studies on glucose-homoeostasis markers also showed increased risks with higher air pollutants levels, but the studies were too heterogeneous for meta-analysis. Overall, patients with diabetes might be more vulnerable to PM.

CONCLUSIONS

Recent publications strengthened the evidence for adverse effects of ambient air pollutants exposure (especially for PM) on T2D and that diabetic patients might be more vulnerable to air pollutants exposure.

The impact of air pollution on the incidence of diabetes and survival among prevalent diabetes cases

PURPOSE

Growing evidence implicates ambient air pollutants in the development of major chronic diseases and premature mortality. However, epidemiologic evidence linking air pollution to diabetes remains inconclusive. This study sought to determine the relationships between selected air pollutants (nitrogen dioxide [NO₂], fine particulate matter [PM_2.5], ozone [O₃], and oxidant capacity [Ox; the redox-weighted average of O₃ and NO₂]) and the incidence of diabetes, as well as the risk of cardiovascular or diabetes mortality among individuals with prevalent diabetes.

RESEARCH DESIGN AND METHODS

We followed two cohorts, which included 4.8 million Ontario adults free of diabetes and 452,590 Ontario adults with prevalent diabetes, from 2001 to 2015. Area-level air pollution exposures were assigned to subjects' residential areas, and outcomes were ascertained using health administrative data with validated algorithms. We estimated hazard ratios for the association between each air pollutant and outcome using Cox proportional hazards models, and modelled the shape of the concentration-response relationships.

RESULTS

Over the study period, 790,461 individuals were diagnosed with diabetes. Among those with prevalent diabetes, 26,653 died from diabetes and 64,773 died from cardiovascular diseases. For incident diabetes, each IQR increase in NO₂ had a hazard ratio of 1.04 (95% CI: 1.03-1.05). This relationship was relatively robust to all sensitivity analyses considered, and exhibited a near-linear shape. There were also positive associations between incident diabetes and PM_2.5, O₃, and Ox, but these estimates were somewhat sensitive to different models considered. Among those with prevalent diabetes, almost all pollutants were associated with increased diabetes and cardiovascular mortality risk. The strongest association was observed between diabetes mortality and exposure to NO₂ (HR = 1.08, 95% CI: 1.02-1.13).

CONCLUSIONS

Selected air pollutants, especially NO₂, were linked to an increased risk of incident diabetes, as well as risk of cardiovascular or diabetes mortality among persons with prevalent diabetes. As NO₂ is frequently used as a proxy for road traffic exposures, this result may indicate that traffic-related air pollution has the strongest effect on diabetes etiology and survival after diabetes development.

Risk Analysis of Air Pollution and Meteorological Factors Affecting the Incidence of Diabetes in the Elderly Population in Northern China

BACKGROUND

Research investigating the effect of air pollution on diabetes incidence is mostly conducted in Europe and the United States and often produces conflicting results. The link between meteorological factors and diabetes incidence remains to be explored. We aimed to explore associations between air pollution and diabetes incidence and to estimate the nonlinear and lag effects of meteorological factors on diabetes incidence.

METHODS

Our study included 19,000 people aged ≥60 years from the Binhai New District without diabetes at baseline. The generalized additive model (GAM) and the distributed lag nonlinear model (DLNM) were used to explore the effect of air pollutants and meteorological factors on the incidence of diabetes. In the model combining the GAM and DLNM, the impact of each factor (delayed by 30 days) was first observed separately to select statistically significant factors, which were then incorporated into the final multivariate model. The association between air pollution and the incidence of diabetes was assessed in subgroups based on age, sex, and body mass index (BMI).

RESULTS

We found that cumulative RRs for diabetes incidence were 1.026 (1.011-1.040), 1.019 (1.012-1.026), and 1.051 (1.019-1.083) per 10 μg/m³ increase in PM_2.5, PM₁₀, and NO₂, respectively, as well as 1.156 (1.058-1.264) per 1 mg/m³ increase in CO in a single-pollutant model. Increased temperature, excessive humidity or dryness, and shortened sunshine duration were positively correlated with the incidence of diabetes in single-factor models. After adjusting for temperature, humidity, and sunshine, the risk of diabetes increased by 9.2% (95% confidence interval (CI):2.1%-16.8%) per 10 μg/m³ increase in PM_2.5. We also found that women, the elderly (≥75 years), and obese subjects were more susceptible to the effect of PM_2.5.

CONCLUSION

Our data suggest that PM_2.5 is positively correlated with the incidence of diabetes in the elderly, and the relationship between various meteorological factors and diabetes in the elderly is nonlinear.

The Metabolic Response to Ozone

The respiratory effects of O3 are well established. High ambient O3 concentrations are associated with respiratory symptoms, declines in pulmonary function, asthma exacerbations, and even mortality. The metabolic effects of O3 are less well appreciated. Here we review data indicating that O3 exposure leads to glucose intolerance and hyperlipidemia, characteristics of the metabolic syndrome. We also review the role of stress hormones in these events. We describe how the metabolic effects of O3, including effects within the lungs, are exacerbated in the setting of the metabolic derangements of obesity and we discuss epidemiological data indicating an association between ambient O3 exposure and diabetes. We conclude by describing the role of the gut microbiome in the regulation of metabolism and by discussing data indicating a link between the gut microbiome and pulmonary responses to O3.

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.

Ambient air pollution and risk of type 2 diabetes in the Chinese

We performed a time series analysis to investigate the potential association between exposure to ambient air pollution and type 2 diabetes (T2D) incidence in the Chinese population. Monthly time series data between 2008 and 2015 on ambient air pollutants and incident T2D (N = 25,130) were obtained from the Environment Monitoring Center of Ningbo and the Chronic Disease Surveillance System of Ningbo. Relative risks (RRs) and 95% confidence intervals (95% CIs) of incident T2D per 10 μg/m³ increases in ambient air pollutants were estimated from Poisson generalized additive models. Exposure to particulate matter < 10 μm (PM₁₀) and sulfur dioxide (SO₂) was associated with increased T2D incidence. The relative risks (RRs) of each increment in 10 μg/m³ of PM₁₀ and SO₂ were 1.62 (95% CI, 1.16-2.28) and 1.63 (95% CI, 1.12-2.38) for overall participants, whereas for ozone (O₃) exposure, the RRs were 0.78 (95% CI, 0.68-0.90) for overall participants, 0.78 (95% CI, 0.69-0.90) for males, and 0.78 (95% CI, 0.67-0.91) for females, respectively. Exposure to PM₁₀ and SO₂ is positively associated with T2D incidence, whereas O₃ is negatively associated with T2D incidence.

Long-term exposure to ambient fine particulate matter (PM2.5) and incident type 2 diabetes: a longitudinal cohort study

AIMS/HYPOTHESIS

Information on the associations of long-term exposure to fine particulate matter (with an aerodynamic diameter less than 2.5 μm; PM_2.5) with the development of type 2 diabetes is scarce, especially for south-east Asia, where most countries are experiencing serious air pollution. This study aimed to investigate the long-term effects of exposure to ambient PM_2.5 on the incidence of type 2 diabetes in a population of Taiwanese adults.

METHODS

A total of 147,908 participants without diabetes, at least 18 years of age, were recruited in a standard medical examination programme between 2001 and 2014. They were encouraged to take medical examinations periodically and underwent at least two measurements of fasting plasma glucose (FPG). Incident type 2 diabetes was identified as FPG ≥7 mmol/l or self-reported physician-diagnosed diabetes in the subsequent medical visits. The PM_2.5 concentration at each participant's address was estimated using a satellite-based spatiotemporal model with a resolution of 1 × 1 km². The 2 year average of PM_2.5 concentrations (i.e. the year of and the year before the medical examination) was treated as an indicator of long-term exposure to ambient PM_2.5 air pollution. We performed Cox regression models with time-dependent covariates to analyse the long-term effects of exposure to PM_2.5 on the incidence of type 2 diabetes. A wide range of covariates were introduced in the models to control for potential effects, including age, sex, education, season, year, smoking status, alcohol drinking, physical activity, vegetable intake, fruit intake, occupational exposure, BMI, hypertension and dyslipidaemia (all were treated as time-dependent covariates except for sex).

RESULTS

Compared with the participants exposed to the first quartile of ambient PM_2.5, participants exposed to the second, third and fourth quartiles of ambient PM_2.5 had HRs of 1.28 (95% CI 1.18, 1.39), 1.27 (95% CI 1.17, 1.38) and 1.16 (95% CI 1.07, 1.26), respectively, for the incidence of type 2 diabetes. Participants who drank occasionally or regularly (more than once per week) or who had a lower BMI (<23 kg/m²) were more sensitive to the long-term effects of exposure to ambient PM_2.5.

CONCLUSIONS/INTERPRETATION

Long-term exposure to ambient PM_2.5 appears to be associated with a higher risk of developing type 2 diabetes in this Asian population experiencing high levels of air pollution.

Interactive effects of changing stratospheric ozone and climate on tropospheric composition and air quality, and the consequences for human and ecosystem health

The composition of the air we breathe is determined by emissions, weather, and photochemical transformations induced by solar UV radiation. Photochemical reactions of many emitted chemical compounds can generate important (secondary) pollutants including ground-level ozone (O₃) and some particulate matter, known to be detrimental to human health and ecosystems. Poor air quality is the major environmental cause of premature deaths globally, and even a small decrease in air quality can translate into a large increase in the number of deaths. In many regions of the globe, changes in emissions of pollutants have caused significant changes in air quality. Short-term variability in the weather as well as long-term climatic trends can affect ground-level pollution through several mechanisms. These include large-scale changes in the transport of O₃ from the stratosphere to the troposphere, winds, clouds, and patterns of precipitation. Long-term trends in UV radiation, particularly related to the depletion and recovery of stratospheric ozone, are also expected to result in changes in air quality as well as the self-cleaning capacity of the global atmosphere. The increased use of substitutes for ozone-depleting substances, in response to the Montreal Protocol, does not currently pose a significant risk to the environment. This includes both the direct emissions of substitutes during use and their atmospheric degradation products (e.g. trifluoroacetic acid, TFA).

Development of a large-scale computer-controlled ozone inhalation exposure system for rodents

Objective: Complete systems for laboratory-based inhalation toxicology studies are typically not commercially available; therefore, inhalation toxicologists utilize custom-made exposure systems. Here we report on the design, construction, testing, operation and maintenance of a newly developed in vivo rodent ozone inhalation exposure system. Materials and methods: Key design requirements for the system included large-capacity exposure chambers to facilitate studies with large sample sizes, automatic and precise control of chamber ozone concentrations, as well as automated data collection on airflow and environmental conditions. The exposure system contains two Hazelton H-1000 stainless steel and glass exposure chambers, each providing capacity for up to 180 mice or 96 rats. We developed an empirically tuned proportional-integral-derivative control loop that provides stable ozone concentrations throughout the exposure period (typically 3h), after a short ramp time (∼8 min), and across a tested concentration range of 0.2-2 ppm. Specific details on the combination of analog and digital input/output system for environmental data acquisition, control and safety systems are provided, and we outline the steps involved in maintenance and calibration of the system. Results: We show that the exposure system produces consistent ozone exposures both within and across experiments, as evidenced by low coefficients of variation in chamber ozone concentration and consistent biological responses (airway inflammation) in mice, respectively. Conclusion: Thus, we have created a large and robust ozone exposure system, facilitating future studies on the health effects of ozone in rodents.

Ambient fine particulate pollution associated with diabetes mellitus among the elderly aged 50 years and older in China

The linkage between ambient air pollution exposure and occurrence of diabetes mellitus is not well defined. This study examined the association between exposure to fine particles (PM_2.5) and the prevalence of diabetes among Chinese elderly people. We surveyed 11,504 adults aged ≥50 years in China, estimated the annual concentrations of ambient PM_2.5 using a satellite-based model of aerosol optical depth information. We employed a generalized mixed effects model to examine the association between PM_2.5 and the prevalence of diabetes and explored potential effect modifiers. We estimated diabetes burden attributable to ambient PM_2.5 if the observed association is indeed causal. The diabetes prevalence among the participants was 6.5% (n = 745). Our analysis found a statistically significant association between PM_2.5 and diabetes. The adjusted odds ratio was 1.27 (95% confidence interval (CI), 1.12, 1.43) for each 10 μg/m³ increment in ambient PM_2.5. Stratified analyses found a lower association among the participants with higher consumption of fruit. We estimated that 22.02% (95% CI: 8.59%, 43.29%) of the diabetes cases could be ascribable to ambient PM_2.5. Our finding suggests that PM_2.5 exposures could increase the risk of diabetes, and if causal, could be responsible for substantial burden of diabetes among the Chinese elderly; and higher intakes of fruit might reduce the harmful effects of PM_2.5, however, due to the limitation of the cross-sectional study design, more studies are warranted to confirm this observation.

Associations of Exposure to Air Pollution with Insulin Resistance: A Systematic Review and Meta-Analysis

In this article, we review the available evidence and explore the association between air pollution and insulin resistance (IR) using meta-analytic techniques. Cohort studies published before January 2018 were selected through English-language literature searches in nine databases. Six cohort studies were included in our sample, which assessed air pollutants including PM2.5 (particulate matter with an aerodynamic diameter less than or equal to 2.5 μm), NO₂(nitrogen dioxide), and PM10 (particulate matter with an aerodynamic diameter less than 10 μm). Percentage change in insulin or insulin resistance associated with air pollutants with corresponding 95% confidence interval (CI) was used to evaluate the risk. A pooled effect (percentage change) was observed, with a 1 μg/m³ increase in NO₂ associated with a significant 1.25% change (95% CI: 0.67, 1.84; I² = 0.00%, p = 0.07) in the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and a 0.60% change (95% CI: 0.17, 1.03; I² = 30.94%, p = 0.27) in insulin. Similar to the analysis of NO₂, a 1 μg/m³ increase in PM10 was associated with a significant 2.77% change (95% CI: 0.67, 4.87; I² = 94.98%, p < 0.0001) in HOMA-IR and a 2.75% change in insulin (95% CI: 0.45, 5.04; I² = 58.66%, p = 0.057). No significant associations were found between PM2.5 and insulin resistance biomarkers. We conclude that increased exposure to air pollution can lead to insulin resistance, further leading to diabetes and cardiometabolic diseases. Clinicians should consider the environmental exposure of patients when making screening and treatment decisions for them.

Air Pollution and Cardiovascular Disease: A Focus on Vulnerable Populations Worldwide

Purpose of review

Certain subgroups defined by sociodemographics (race/ethnicity, age, sex and socioeconomic status [SES]), geographic location (rural vs. urban), comorbid conditions and country economic conditions (developed vs. developing) may disproportionately suffer the adverse cardiovascular effects of exposure to ambient air pollution. Yet, previous reviews have had a broad focus on the general population without consideration of these potentially vulnerable populations.

Recent findings

Over the past decade, a wealth of epidemiologic studies have linked air pollutants including particulate matter, oxides of nitrogen, and carbon monoxide to cardiovascular disease (CVD) risk factors, subclinical CVD, clinical cardiovascular outcomes and cardiovascular mortality in certain susceptible populations. Highest risk for poor CVD outcomes from air pollution exist in racial/ethnic minorities, especially in blacks compared to whites in the U.S, those at low SES, elderly populations, women, those with certain comorbid conditions and developing countries compared to developed countries. However, findings are less consistent for urban compared to rural populations.

Summary

Vulnerable subgroups including racial/ethnic minorities, women, the elderly, smokers, diabetics and those with prior heart disease had higher risk for adverse cardiovascular outcomes from exposure to air pollution. There is limited data from developing countries where concentrations of air pollutants are more extreme and cardiovascular event rates are higher than that of developed countries. Further epidemiologic studies are needed to understand and address the marked disparities in CVD risk conferred by air pollution globally, particularly among these vulnerable subgroups.

Evidence for the Formation of Ozone (or Ozone-Like Oxidants) by the Reaction of Singlet Oxygen with Amino Acids

Antibodies or some amino acids, namely, cysteine, methionine, histidine, and tryptophan, were previously reported to catalyse the conversion of singlet oxygen (1O2) to ozone (O3). The originally proposed mechanism for such biological ozone formation was that antibodies or amino acids catalyse the oxidation of water molecules by singlet oxygen to yield dihydrogen trioxide (HOOOH) as a precursor of ozone and hydrogen peroxide (H2O2). However, because HOOOH readily decomposes to form water and singlet oxygen rather than ozone and hydrogen peroxide, an alternative hypothesis has been proposed; ozone is formed due to the reaction of singlet oxygen with amino acids to form polyoxidic amino acid derivatives as ozone precursors. Evidence in support of the latter hypothesis is presented in this article, in that in the presence of singlet oxygen, methionine sulfoxide (RS(O)CH3), an oxidation product of methionine (RSCH3), was found to promote reactions that can best be attributed to the trioxidic anionic derivative RS+(OOO−)CH3 or ozone.

Association between long-term exposure to ambient air pollution and diabetes mortality in the US

OBJECTIVE

Recent mechanistic and epidemiological evidence implicates air pollution as a potential risk factor for diabetes; however, mortality risks have not been evaluated in a large US cohort assessing exposures to multiple pollutants with detailed consideration of personal risk factors for diabetes.

RESEARCH DESIGN AND METHODS

We assessed the effects of long-term ambient air pollution exposures on diabetes mortality in the NIH-AARP Diet and Health Study, a cohort of approximately a half million subjects across the contiguous U.S. The cohort, with a follow-up period between 1995 and 2011, was linked to residential census tract estimates for annual mean concentration levels of PM_2.5, NO₂, and O₃. Associations between the air pollutants and the risk of diabetes mortality (N = 3598) were evaluated using multivariate Cox proportional hazards models adjusted for both individual-level and census-level contextual covariates.

RESULTS

Diabetes mortality was significantly associated with increasing levels of both PM_2.5 (HR = 1.19; 95% CI: 1.03-1.39 per 10 μg/m³) and NO₂ (HR = 1.09; 95% CI: 1.01-1.18 per 10 ppb). The strength of the relationship was robust to alternate exposure assessments and model specifications. We also observed significant effect modification, with elevated mortality risks observed among those with higher BMI and lower levels of fruit consumption.

CONCLUSIONS

We found that long-term exposure to PM_2.5 and NO₂, but not O₃, is related to increased risk of diabetes mortality in the U.S, with attenuation of adverse effects by lower BMI and higher fruit consumption, suggesting that air pollution is involved in the etiology and/or control of diabetes.

Association between long-term exposure to ambient air pollution and diabetes mortality in the US

OBJECTIVE

Recent mechanistic and epidemiological evidence implicates air pollution as a potential risk factor for diabetes; however, mortality risks have not been evaluated in a large US cohort assessing exposures to multiple pollutants with detailed consideration of personal risk factors for diabetes.

RESEARCH DESIGN AND METHODS

We assessed the effects of long-term ambient air pollution exposures on diabetes mortality in the NIH-AARP Diet and Health Study, a cohort of approximately a half million subjects across the contiguous U.S. The cohort, with a follow-up period between 1995 and 2011, was linked to residential census tract estimates for annual mean concentration levels of PM_2.5, NO₂, and O₃. Associations between the air pollutants and the risk of diabetes mortality (N = 3598) were evaluated using multivariate Cox proportional hazards models adjusted for both individual-level and census-level contextual covariates.

RESULTS

Diabetes mortality was significantly associated with increasing levels of both PM_2.5 (HR = 1.19; 95% CI: 1.03-1.39 per 10 μg/m³) and NO₂ (HR = 1.09; 95% CI: 1.01-1.18 per 10 ppb). The strength of the relationship was robust to alternate exposure assessments and model specifications. We also observed significant effect modification, with elevated mortality risks observed among those with higher BMI and lower levels of fruit consumption.

CONCLUSIONS

We found that long-term exposure to PM_2.5 and NO₂, but not O₃, is related to increased risk of diabetes mortality in the U.S, with attenuation of adverse effects by lower BMI and higher fruit consumption, suggesting that air pollution is involved in the etiology and/or control of diabetes.

The impact of occupational exposure to traffic-related air pollution among professional motorcyclists from Porto Alegre, Brazil, and its association with genetic and oxidative damage

Vehicles play an important role in modern life; however, they also generate hazards. Occupational exposed subjects are in long-term contact with harmful products, which sets these professionals in a susceptible group to air pollutant damage. The aims of this study were to quantify individual exposure to pollutant gases and chemical elements and to evaluate oxidative and genetic damage in professional motorcyclists and office workers. We recruited professional motorcyclists and office workers from Porto Alegre, Brazil, between January and December 2016. Individual exposure to air pollutants was assessed by passive monitoring. Fingernail trace elements were determined by using inductively coupled plasma mass spectrometry. Oxidative stress biomarkers were quantified spectrophotometrically, and genotoxicity was evaluated by micronuclei assay. Individual exposure to NO₂ and O₃, trace element content (Sb, Pt, As, Cd, V, Mn, and Co), oxidative stress factors, and genetic damage were statistically higher in professional motorcyclists (p < 0.05). Moreover, NO₂ and O₃ levels showed very strong positive correlation with plasmatic lipid peroxidation (p < 0.001 and r = 0.8849 and 0.8995) and strong positive correlation with micronuclei frequency (p < 0.001 and r = 0.7683 and 0.7280). Results suggest that professional motorcyclists are at high risk due to long-term air pollution exposure, which implies in the onset of several harmful effects and worsening of pre-existent diseases.