Air-Pollution and Cardiometabolic Diseases (AIRCMD): a prospective study investigating the impact of air pollution exposure and propensity for type II diabetes

Household Air Pollution, Physical Activity, and the Risk of Frailty Among Middle-Aged and Older Adults: A Cohort Study

OBJECTIVE

This study aims to explore the relationship among household air pollution, physical activity (PA), and the risk of frailty among middle-aged and older adults.

DESIGN

Prospective cohort study.

SETTING AND PARTICIPANTS

A total of 10,561 participants from the 2011-2020 China Health and Retirement Longitudinal Study (CHARLS) were included.

METHODS

PA was assessed using the International Physical Activity Questionnaire (IPAQ), and household air pollution was measured based on cooking and heating. Frailty risk was evaluated using the frailty index (FI). Cox proportional hazards regression models were used for statistical analysis.

RESULTS

During the follow-up, 1101 participants developed frailty. After adjusting for all covariates, compared with participants who consistently used solid fuels, transforming solid fuels to cleaner fuels for cooking [hazard ratio (HR), 0.671; 95% CI, 0.560-0.803] and heating (HR, 0.373; 95% CI, 0.292-0.479) reduced the risk of frailty by 32.9% and 62.7%, respectively. Conversely, transforming cleaner fuels to solid fuels for cooking increased the risk of frailty by 27.5% (HR, 1.275; 95% CI, 1.006-1.599). Sufficient PA for 3 to 4 years (HR, 0.658; 95% CI, 0.542-0.798) and for ≥5 years (HR, 0.490; 95% CI, 0.398-0.602) reduced frailty risk by 34.2% and 51.0%, respectively. Both transforming solid household fuels to cleaner household fuels with 3 or more years of sufficient PA and transforming cleaner household fuels to solid household fuels with 3 or more years of sufficient PA were significantly associated with lower frailty risk.

CONCLUSIONS AND IMPLICATIONS

Both transforming solid household fuels to cleaner household fuels and maintaining sufficient PA for 3 or more years were significantly associated with lower risk of frailty. Conversely, transforming cooking-related cleaner fuels to cooking-related solid fuels can increase frailty risk. In addition, 3 or more years of sufficient PA can superimpose the benefits of transforming solid household fuels to cleaner household fuels, offsetting the negative effects of transforming cleaner household fuels to solid household fuels.

Diesel Particulate Matter (DPM)-Induced Metabolic Disruption in Mice Is Mitigated by Sodium Copper Chlorophyllin (SCC)

BACKGROUND/OBJECTIVES

The increasing prevalence of metabolic disorders underscores the need for effective interventions to mitigate environmental stressors such as diesel particulate matter (DPM), a major urban air pollutant. DPM is composed of fine carbonaceous particles that can induce systemic inflammation. This phenomenon results in metabolic dysfunction such as adipocyte hypertrophy, insulin resistance, and mitochondrial impairment in body tissues.

METHODS

This study investigated the impact of DPM exposure on murine lung, skeletal muscle, and adipose tissues and evaluated the protective effects of supplementation with sodium copper chlorophyllin (SCC).

RESULTS

Compared to controls, DPM-exposed mice exhibited significantly elevated oxidative stress markers (* p ≤ 0.05), systemic pro-inflammatory cytokines including TNF-α, MCP-1, IL-6, and IL-1β (* p ≤ 0.05), and adipocyte hypertrophy of both subcutaneous and visceral fat depots, supporting prior findings of DPM-induced metabolic dysfunction. SCC supplementation restored pulmonary ATP levels (* p ≤ 0.05), significantly reduced ROS production in lung and muscle tissue (* p ≤ 0.05), and significantly attenuated DPM-induced inflammatory cytokine secretion (* p ≤ 0.05), while lessening DPM-induced adipocyte hypertrophy.

CONCLUSIONS

These effects highlight the antioxidant and anti-inflammatory potential of SCC, which likely mitigates systemic metabolic compromise by modulating mitochondrial function and inflammatory pathways. This study further demonstrated that SCC supplementation may be an effective intervention for alleviating the adverse effects of DPM exposure on metabolic and inflammatory compromise. Additional research may clarify a role for SCC in reducing systemic health risks associated with air pollution and offer a foundation for future translational research in human populations exposed to environmental pollutants.

Joint exposure to multiple air pollutants and residual cardiovascular risk in hypertension

BACKGROUND

Despite the widespread availability of antihypertensive medications, residual cardiovascular risk of hypertension remained high. Limited studies have investigated the link between air pollution, particularly joint exposure to multiple air pollutants, with residual cardiovascular risk of hypertension.

METHODS

1981 hypertensive patients (≥ 18 years) from an ongoing longitudinal cohort in China, were enrolled between 2013 and 2019. Using high-quality datasets from China, the ground-level air pollutants concentrations, including PM2.5, PM2.5-10, SO2, O3, CO and NO2, at each participant's residence were calculated. The relationships between individual and multiple air pollutants with the residual cardiovascular risk were assessed by Cox proportional hazards models, air pollution score analyses and Bayesian Kernel Machine Regression model.

RESULTS

Over an average follow-up period of 2.24 years (SD, 1.25), 706 hypertensive patients developed cardiovascular disease. In the single-pollutant analysis, higher concentrations of PM2.5, PM2.5-10, SO2 and CO were linked to increased residual cardiovascular risk. The air pollution score analyses and Bayesian kernel machine regression suggested that combined exposure to multiple air pollutants had a positive association with the residual cardiovascular risk, and NO2 played a dominant role. With higher NO2 concentrations, the hazard ratio of individual pollutants to residual cardiovascular risk increased.

CONCLUSIONS

Prolonged exposure to a mixture of various air pollutants is linked to elevated residual cardiovascular risk in individuals with hypertension. Apart from taking antihypertensive medication and adopting healthy lifestyle behaviors, hypertensive patients should lower air pollutant exposure to decrease residual cardiovascular risk.

Changes in PM2.5-related diabetes risk under the implementation of the clean air act in Shanghai

OBJECTIVES

We examined the associations between PM2.5 exposure and Type 2 diabetes mellitus risk under the implementation of the Clean Air Act (CAA) among high-risk population for diabetes in Shanghai.

METHODS

A total of 10,499 subjects from the Shanghai High-Risk Diabetic Screen (SHiDS) project between 2002 and 2018, linked with remotely sensed PM2.5 concentrations, were enrolled in this study. Ordinary least squares and logistic regression were applied to explore associations between PM2.5 and diabetes risk in various exposure periods.

RESULTS

In year 2002-2013 (before CAA), the diabetes risk increased 7.5 % (95 % CI: 1.018-1.137), 8.0 % (95 % CI: 1.022-1.142) and 7.9 % (95 % CI: 1.021-1.141) under each 10 μg/m3 increase of long-term (1, 2 and 3 years) PM2.5 exposure, respectively. Elevated PM2.5 exposure were also associated with a significant increase in glycemic parameters before CAA implementation. However, in the year 2014-2018 (after CAA), the associations between PM2.5 exposure and diabetes risk were not significant after controlling for potential confounders.

CONCLUSION

Our findings suggest that long-term and high-level exposure to PM2.5 was associated with increased prevalence of diabetes. Moreover, the implementation of CAA might ameliorate PM2.5-related diabetes risk.

Association Between Long‑Term Exposure to Air Pollution and the Rate of Mortality After Hip Fracture Surgery in Patients Older Than 60 Years: Nationwide Cohort Study in Taiwan

BACKGROUND

To enhance postoperative patient survival, particularly in older adults, understanding the predictors of mortality following hip fracture becomes paramount. Air pollution, a prominent global environmental issue, has been linked to heightened morbidity and mortality across a spectrum of diseases. Nevertheless, the precise impact of air pollution on hip fracture outcomes remains elusive.

OBJECTIVE

This retrospective study aims to comprehensively investigate the profound influence of a decade-long exposure to 12 diverse air pollutants on the risk of post-hip fracture mortality among older Taiwanese patients (older than 60 years). We hypothesized that enduring long-term exposure to air pollution would significantly elevate the 1-year mortality rate following hip fracture surgery.

METHODS

From Taiwan's National Health Insurance Research Database, we obtained the data of patients who underwent hip fracture surgery between July 1, 2003, and December 31, 2013. Using patients' insurance registration data, we estimated their cumulative exposure levels to sulfur dioxide (SO2), carbon dioxide (CO2), carbon monoxide (CO), ozone (O3), particulate matter having a size of <10 μm (PM10), particulate matter having a size of <2.5 μm (PM2.5), nitrogen oxides (NOX), nitrogen monoxide (NO), nitrogen dioxide (NO2), total hydrocarbons (THC), nonmethane hydrocarbons (NMHC), and methane (CH4). We quantified the dose-response relationship between these air pollutants and the risk of mortality by calculating hazard ratios associated with a 1 SD increase in exposure levels over a decade.

RESULTS

Long-term exposure to SO2, CO, PM10, PM2.5, NOX, NO, NO2, THC, NMHC, and CH4 demonstrated significant associations with heightened all-cause mortality risk within 1 year post hip fracture surgery among older adults. For older adults, each 1 SD increment in the average exposure levels of SO2, CO, PM10, PM2.5, NOX, NO, NO2, THC, NMHC, and CH4 corresponded to a substantial escalation in mortality risk, with increments of 14%, 49%, 18%, 12%, 41%, 33%, 38%, 20%, 9%, and 26%, respectively. We further noted a 35% reduction in the hazard ratio for O3 exposure suggesting a potential protective effect, along with a trend of potentially protective effects of CO2.

CONCLUSIONS

This comprehensive nationwide retrospective study, grounded in a population-based approach, demonstrated that long-term exposure to specific air pollutants significantly increased the risk of all-cause mortality within 1 year after hip fracture surgery in older Taiwanese adults. A reduction in the levels of SO2, CO, PM10, PM2.5, NOX, NO, NO2, THC, NMHC, and CH4 may reduce the risk of mortality after hip fracture surgery. This study provides robust evidence and highlights the substantial impact of air pollution on the outcomes of hip fractures.

Early pregnancy particulate matter exposure, pre-pregnancy adiposity and risk of gestational diabetes mellitus in Finnish primiparous women: An observational cohort study

AIMS

To evaluate the association between the exposure of particulate matter with an aerodynamic diameter of ≤ 2.5μm (PM_2.5) and with an aerodynamic diameter of ≤ 10μm (PM₁₀) over the first trimester and the risk of gestational diabetes mellitus (GDM), and to assess whether maternal pre-pregnancy body mass index (BMI) modified the GDM risk.

METHODS

All Finnish primiparous women without previously diagnosed diabetes who delivered between 2009 and 2015 in the city of Vantaa, Finland, composed the study cohort (N = 6189). Diagnosis of GDM was based on a standard 75 g 2-hour oral glucose tolerance test. The average daily concentration of PM_2.5 and PM₁₀ over the first trimester was calculated individually for each woman. The relationship between exposure of PM_2.5 and PM₁₀ and GDM was analyzed with logistic models.

RESULTS

No association was observed between the average daily concentrations of PM_2.5 and PM₁₀ over the first trimester and the GDM risk. When simultaneously taking BMI and PM₁₀ into account both mean daily PM₁₀ concentration (p = 0.047) and pre-pregnancy BMI (p = 0.016) increased GDM risk independently and an interaction (p = 0.013) was observed between PM₁₀ concentration and pre-pregnancy BMI.

CONCLUSIONS

Even globally low PM₁₀ exposure level together with elevated maternal pre-pregnancy BMI seems to increase the GDM risk.

Association of long-term exposure to ambient air pollutants with cardiac structure and cardiovascular function in Chinese adults

Epidemiological evidence increasingly suggests that air pollutants are intimately associated with the incidence and mortality of cardiovascular diseases (CVDs). However, studies on the association between chronic exposure to air pollutants and changes in left cardiac function and structure are limited. In our cross-sectional study, 3145 participants were enrolled from 6 provinces to explore the relationship between long-term air pollutants, cardiac structure, and cardiovascular function (e.g., blood lipids, blood pressure and pulse) in Chinese adults. Our study showed that exposure to five pollutants (NO₂, O₃, PM₁, PM_2.5 and PM₁₀) was associated with reduced left ventricular systolic function based on EF and SV parameters. These pollutants were also associated with increased pulses, where smaller particle sizes correlated significantly with pulses. Second, except for O₃, four pollutants were associated with decreased left ventricular diastolic parameters LVIDd and EDV and increased cardiac structural parameter IVSd. In addition, exposures to NO₂, O₃ and PM₁₀ were positively correlated with triglycerides in blood lipids. Overall, this study showed that chronic pollutant exposure is strongly associated with impaired left ventricular function in Chinese adults.

Serum branched-chain amino acids modifies the associations between air pollutants and insulin resistance

Growing evidence supports that air pollution exposure has become a risk factor of type II diabetes mellitus through the induction of insulin resistance (IR), but the presented findings did not provide a consistent relationship between air pollution exposure and IR in the temporal scale and the magnitude. Reported associated with IR and air pollution exposure, branched-chain amino acids (BCAAs) in blood might modify the association between air pollution exposure and IR. We took advantage of an existing panel study on elderly people who were healthy or with pre-diabetes. Amino acids were analyzed from the serum samples using a UPLC-QQQ-MS, and the homeostasis model assessment of insulin resistance (HOMA-IR) values were calculated to represent the levels of IR in each visit. Exposures to PM_2.5, NO₂, SO₂, CO, O₃, and black carbon (BC) were estimated using data from a monitoring station. Linear mixed-effects models were applied to estimate the associations between the air pollution and HOMA-IR, as well as the modifying effects of BCAAs. We found significantly higher concentrations of BCAAs in the pre-diabetic subjects than healthy ones. The concentrations of BCAAs were all significantly associated with HOMA-IR. For subjects with high-level BCAAs, HOMA-IR was positively associated with an IQR increase in PM_2.5, NO₂, BC, and CO at lag day 2 and in PM_2.5, SO₂, NO₂, BC, and CO at lag day 7. While for subjects with low-level BCAAs, there was no significant association observed at any lag day except for CO at lag day 5. The study provided evidence that circulating BCAAs may modify the relationship between air pollution exposure and the level of insulin resistance in humans.

Acute effect of fine particulate matter on blood pressure, heart rate and related inflammation biomarkers: A panel study in healthy adults

Epidemiological evidence of short-term fine particulate matter (PM2.5) exposure on blood pressure (BP), heart rate (HR) and related inflammation biomarkers has been inconsistent. We aimed to explore the acute effect of PM2.5 on BP, HR and the mediation effect of related inflammation biomarkers. A total of 32 healthy college students were recruited to perform 4 h of exposure at two sites with different PM2.5 concentrations in Wuhan between May 2019 and June 2019. The individual levels of PM2.5 concentration, BP and HR were measured hourly for each participant. Blood was drawn from each participant after each visit and we measured the levels of inflammation markers, including serum high-sensitivity C-reactive protein and plasma fibrinogen. Linear mixed-effect models were to explore the acute effect of PM2.5 exposure on BP, HR, and related inflammation biomarkers. In addition, we evaluated related inflammation biomarkers as the mediator in the association of PM2.5 and cardiovascular health indicators. The results showed that a 10 μg/m3 increment in PM2.5 concentration was associated with an increase of 0.84 (95% CI: 0.54, 1.15) beats/min (bpm) in HR and a 3.52% (95% CI: 1.60%, 5.48%) increase in fibrinogen. The lag effect model showed that the strongest effect on HR was observed at lag 3 h of PM2.5 exposure [1.96 bpm (95% CI: 1.19, 2.75)], but for fibrinogen, delayed exposure attenuated the association. Increased fibrinogen levels may account for 39.07% (P = 0.44) of the elevated HR by PM2.5. Null association was observed when it comes to short-term PM2.5 exposure and BP. Short-term exposure to PM2.5 was associated with elevated HR and increased fibrinogen levels. But our finding was not enough to suggest that exposure to PM2.5 might induce adverse cardiovascular effects by the pathway of inflammation.

Association of PM2.5 with Insulin Resistance Signaling Pathways on a Microfluidic Liver-Kidney Microphysiological System (LK-MPS) Device

Insulin resistance (IR) is a typical sign of metabolic dysregulation caused by fine particulate matter (PM_2.5), but the underlying signaling has not been clearly determined. Herein, a microfluidic liver-kidney microphysiological system (LK-MPS) is presented to assess the signaling pathways of IR generated by PM_2.5 at 200 μg/mL for 24 h. The LK-MPS device consisted of a biomimetic liver-kidney architecture and reconstructed two circulation paths: the liver metabolism-kidney excretion (LM-KE) and kidney excretion-liver metabolism (KE-LM), by which PM_2.5 is feasibly distributed in the two organs. Transmission electron microscopy (TEM) analysis revealed that PM_2.5 can embed in the cytoplasm and nuclei, undergo transport by vesicles, and lead to the destruction of mitochondria. Further comprehensive immunofluorescence, enzyme-linked immunosorbent assays (ELISAs) and untargeted metabolomic analyses confirmed that PM_2.5 disturbed the classic IRS-1/AKT signaling pathway (INSR, IRS-1, PI3K, AKT, GLUT2, GLUT4, and FOXO1 downregulated) and IR-related metabolic pathways: UDP-hexosamine (UDP-GlcNAc), gluconeogenesis (β-d-glucose 6-phosphate), and lipid biosynthesis (ceramide (Cer) and triacylglycerol (TG)) pathways, leading to the disorder of glucose levels. Collectively, these disorders aggravate hepatic and renal IR. Pearson's correlation coefficient test showed that elemental carbon (EC), polycyclic aromatic hydrocarbons (PAHs), and metals (Ca, Co, and V) were negatively correlated to the dysregulated proteins (INSR, IRS-1, AKT, FOXO1, GLUT2, and GLUT4). These findings may partially explain IR-related signaling pathways triggered by PM_2.5.

The Impact of Air Pollution on Neurodegenerative Diseases

BACKGROUND

With the development of industrialization in human society, ambient pollutants are becoming more harmful to human health. Epidemiological and toxicological studies indicate that a close relationship exists between particulate matter with a diameter ≤2.5 µm (PM2.5) and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). To further confirm the relationship, we focus on possible relevant mechanisms of oxidative stress and neuroinflammation underlying the association between PM2.5 and neurodegenerative diseases in the review.

METHODS

A literature search was performed on the studies about PM2.5 and neurodegenerative diseases via PubMed. A total of 113 articles published were selected, and 31 studies were included.

RESULTS

PM2.5 can enter the central nervous system through 2 main pathways, the blood-brain barrier and olfactory neurons. The inflammatory response and oxidative stress are 2 primary mechanisms via which PM2.5 leads to toxicity in the brain. PM2.5 abnormally activates microglia, inducing the neuroinflammatory process. Inflammatory markers such as IL-1β play an essential role in neurodegenerative diseases such as AD and PD. Moreover, the association between lipid mechanism disorders related to PM2.5 and neurodegenerative diseases has been gaining momentum.

CONCLUSIONS

In conclusion, PM2.5 could significantly increase the risk of neurological disorders, such as AD and PD. Furthermore, any policy aimed at reducing air-polluting emissions and increasing air quality would be protective in human beings.

Contributions of artifactual materials to the toxicity of anthropogenic soils and street dusts in a highly urbanized terrain

A study was undertaken to test the hypothesis that the presence of fly ash and other artifactual materials (AMs) significantly increases the toxicity of urban soil and street dust. AMs were distinguished as artifacts (artificial particles > 2 mm in size), and particulate artifacts (≤2 mm in size); street dust was the <63 μm fraction of street sediments. Reference artifacts, street dusts, and topsoils representing different land use types in Detroit, Michigan were analyzed for miscellaneous radionuclides, trace elements, magnetic susceptibility (MS), and acetic acid-extractable (leachable) Pb. Background levels were established using native glacial sediments. Street sediments were found to have a roadside provenance, hence street dusts inherited their contamination primarily from local soils. All soils and dusts had radionuclide concentrations similar to background levels, and radiological hazard indices within the safe range. Artifacts, fly ash-impacted soils and street dusts contained elevated concentrations of toxic trace elements, which varied with land use type, but none produced a significant amount of leachable Pb. It is inferred that toxic elements in AMs are not bioavailable because they are occluded within highly insoluble materials. Hence, these results do not support our hypothesis. Rather, AMs contribute to artificially-elevated total concentrations leading to an overestimation of toxicity. MS increased with increasing total concentration, hence proximal sensing can be used to map contamination level, but the weak correlation between total and leachable Pb suggests that such maps do not necessarily indicate the associated biohazard. Home site soils with total Pb concentrations >500 mg kg^-1 were sporadically toxic. Thus, these results argue against street dust as the local cause of seasonally elevated blood-Pb levels in children. Lead-bearing home site soil tracked directly indoors to form house dust is an alternative exposure pathway.

Associations Between Sub-Clinical Markers of Cardiometabolic Risk and Exposure to Residential Indoor Air Pollutants in Healthy Adults in Perth, Western Australia: A Study Protocol

BACKGROUND

A growing body of epidemiological and clinical evidence has implicated air pollution as an emerging risk factor for cardiometabolic disease. Whilst individuals spend up to two-thirds of daily time in their domestic residential environment, very few studies have been designed to objectively measure the sub-clinical markers of cardiometabolic risk with exposure to domestic indoor air pollutants. This cross-sectional study aims to investigate associations between the components of domestic indoor air quality and selected sub-clinical cardiometabolic risk factors in a cohort of healthy adults living in Perth, Western Australia.

METHODS

One hundred and eleven non-smoking adults (65% female) living in non-smoking households who were aged between 35-69 years were recruited for the project. Study subjects were invited to participate in all sections of the study, which included: Domestic indoor air monitoring along with the concurrent 24 h ambulatory monitoring of peripheral and central blood pressure and measures of central hemodynamic indices, standardized questionnaires on aspects relating to current health status and the domestic environment, a 24 h time-activity diary during the monitoring period, and clinic-based health assessment involving collection of blood and urine biomarkers for lipid and glucose profiles, as well as measures of renal function and an analysis of central pulse wave and pulse wave velocity.

RESULTS

This study provides a standardized approach to the study of sub-clinical cardiometabolic health effects that are related to the exposure to indoor air pollution.

CONCLUSION

The findings of this study may provide direction for future research that will further contribute to our understanding of the relationship that exists between indoor air pollution and sub-clinical markers of cardiometabolic risk.

AMPK activation attenuates inflammatory response to reduce ambient PM2.5-induced metabolic disorders in healthy and diabetic mice

Epidemiological and experimental studies have indicated that ambient fine particulate matter (PM_2.5) exposure is associated with the occurrence and development of metabolic disorders such as obesity and type 2 diabetes mellitus (T2DM). However, the mechanism is not clear yet, and there are few studies to explore the possible prevention measure. In this study, C57BL/6 and db/db mice were exposed to concentrated PM_2.5 or filtered air using Shanghai Meteorological and Environmental Animal Exposure System (Shanghai-METAS) for 12 weeks. From week 11, some of the mice were assigned to receive a subcutaneous injection of AMPK activator (AICAR). Lipid metabolism, glucose tolerance, insulin sensitivity and energy homeostasis were measured. Meanwhile, the respiratory, systemic and visceral fat inflammatory response was detected. The results showed that PM_2.5 exposure induced the impairments of glucose tolerance, insulin resistance, lipid metabolism disorders and disturbances of energy metabolism in both C57BL/6 and db/db mice. These impairments might be consistent with the increased respiratory, circulating and visceral adipose tissue (VAT) inflammatory response, which was characterized by the release of IL-6 and TNF-α in lung, serum and VAT. More importantly, AICAR administration led to the significant enhancement of energy metabolism, elevation of AMPK as well as the decreased IL-6 and TNF-α in VAT of PM_2.5-exposed mice, which suggesting that AMPK activation might attenuate the inflammatory responses in VAT via the inhibition of MAPKs and NFκB. The study indicated that exposure to ambient PM_2.5 under the concentration which is often seen in some developing countries could induce the occurrence of metabolic disorders in normal healthy mice and exacerbate metabolic disorders in diabetic mice. The adverse impacts of PM_2.5 on insulin sensitivity, energy homeostasis, lipid metabolism and inflammatory response were associated with AMPK inhibition. AMPK activation might inhibit PM_2.5-induced metabolic disorders via inhibition of inflammatory cytokines release. These findings suggested that AMPK activation is a potential therapy to prevent some of the metabolic disorders attributable to air pollution exposure.

Susceptibility of prediabetes to the health effect of air pollution: a community-based panel study with a nested case-control design

BACKGROUND

Recent studies suggest that people with diabetes or who are at risk of developing diabetes, i.e. prediabetic (preDM), are potentially susceptible to air pollution, but the underlying mechanisms remain unclear because the existing epidemiological studies did not include healthy control groups and only focused on limited health outcomes. We hypothesized that acute exposure to ambient fine particles (PM_2.5) will lead to enhanced pulmonary and cardiometabolic changes in preDM than healthy individuals.

METHODS

We recruited 60 preDM and 60 healthy individuals from a community of 22,343 adults in Beijing China, and arranged each subject to complete up to seven repeated clinical visits with measures of 6 cardiopulmonary biomarkers, 6 cytokines, 4 blood pressure and endothelial function outcomes and 4 glucose metabolism biomarkers.. Moving averaged daily ambient PM_2.5 in preceding 1-14 days was matched to each subject and the PM_2.5 associated effect on multiple biomarkers was estimated and compared between PreDM and healthy subjects based on linear mixed effect model.

RESULTS

All the subjects exhibited significant acute elevation of exhaled nitric oxide, white blood cells, neutrophils, interleukin-1α, and glycated haemoglobin with increased exposure to PM_2.5. PreDM subjects had significant stronger adverse changes compared to healthy subjects in 6 cardiometabolic biomarkers, namely, interleukin-2, interleukin-8, systolic and diastolic blood pressure, augmentation pressure, and glucose. The maximum elevation of these 6 biomarkers in PreDM subjects were 8.6% [CI: 4.1-13.3%], 10.0% [CI: 3.9-16.4%], 1.9% [CI: 0.2-3.6%], 1.2% [CI: - 0.1-2.4%], 5.7% [CI: - 0.1-11.8%], 2.4% [CI: 0.7-4.2%], respectively, per an interquartile increase of ambient PM_2.5 (61.4 μg m^- 3) throughout the exposure window of the preceding 1-14 days. No significant difference was observed for the changes in pulmonary biomarkers between the two groups.

CONCLUSIONS

PreDM individuals are more susceptible to the acute cardiometabolic effect of air pollution than the healthy individuals. A considerable public health burden can be inferred, given the high prevalence of prediabetes and the ubiquity of air pollution in China and worldwide.

Ovariectomy predisposes female rats to fine particulate matter exposure's effects by altering metabolic, oxidative, pro-inflammatory, and heat-shock protein levels

The reduction of estrogen levels, as a result of menopause, is associated with the development of metabolic diseases caused by alterations in oxidative stress (OS), inflammatory biomarkers, and 70-kDa heat-shock protein (HSP70) expression. Additionally, exposure to fine particulate matter air pollution modifies liver OS levels and predisposes organisms to metabolic diseases, such as type 2 diabetes (T2DM). We investigated whether ovariectomy affects hepatic tissue and alters glucose metabolism in female rats exposed to particulate air pollution. First, 24 female Wistar rats received an intranasal instillation of saline or particles suspended in saline 5 times per week for 12 weeks. The animals then received either bilateral ovariectomy (OVX) or false surgery (sham) and continued to receive saline or particles for 12 additional weeks, comprising four groups: CTRL, Polluted, OVX, and Polluted+OVX. Ovariectomy increased body weight and adiposity and promoted edema in hepatic tissue, hypercholesterolemia, glucose intolerance, and a pro-inflammatory profile (reduced IL-10 levels and increased IL-6/IL-10 ratio levels), independent of particle exposure. The Polluted+OVX group showed an increase in neutrophils and neutrophil/lymphocyte ratios, decreased antioxidant defense (SOD activity), and increased liver iHSP70 levels. In conclusion, alterations in the reproductive system predispose female organisms to particulate matter air pollution effects by affecting metabolic, oxidative, pro-inflammatory, and heat-shock protein expression.

Effect of Social Factors and the Natural Environment on the Etiology and Pathogenesis of Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is currently a public health problem worldwide and a threat to human health and social development. The incidence rate of the disease is steadily increasing. Various genetic and environmental factors have been established as influencing the pathogenesis of this disease. However, the influence of social factors and the natural environment on DM incidence should also be considered. Low-grade inflammation could represent a central point of connection integrating all these potential triggers, being partly responsible for the development of insulin resistance. This paper aims to elaborate on the impact of the natural environment and social factors on DM development, with a special focus on six aspects of the pathogenesis of DM: pollution, radiation, psychology, drink, sleep, and exercise. We identified a two-way relationship between T2DM and social and natural environments. Changes in these environments may lead to low-grade inflammation, which in turn induces or aggravates T2DM and vice versa. Poor lifestyle may lead to increased insulin resistance and promote DM development. Improvements in blood glucose control can be achieved through nonenvironmental and behavioral interventions.

Ambient Air Pollution and Biomarkers of Health Effect

Recently, the air pollution situation of our country is very serious along with the development of urbanization and industrialization. Studies indicate that the exposure of air pollution can cause a rise of incidence and mortality of many diseases, such as chronic obstructive pulmonary disease (COPD), asthma, myocardial infarction, and so on. However, there is now growing evidence showing that significant air pollution exposures are associated with early biomarkers in various systems of the body. In order to better prevent and control the damage effect of air pollution, this article summarizes comprehensively epidemiological studies about the bad effects on the biomarkers of respiratory system, cardiovascular system, and genetic and epigenetic system exposure to ambient air pollution.

Exposure to Concentrated Ambient PM2.5 Shortens Lifespan and Induces Inflammation-Associated Signaling and Oxidative Stress in Drosophila

Exposure to ambient PM 2.5 is associated with human premature mortality. However, it has not yet been toxicologically replicated, likely due to the lack of suitable animal models. Drosophila is frequently used in longevity research due to many incomparable merits. The present study aims to validate Drosophila models for PM 2.5 toxicity study through characterizing their biological responses to exposure to concentrated ambient PM 2.5 (CAP). The survivorship curve demonstrated that exposure to CAP markedly reduced lifespan of Drosophila. This antilongevity effect of CAP exposure was observed in both male and female Drosophila, and by comparison, the male was more sensitive [50% survivals: 20 and 48 days, CAP- and filtered air (FA)-exposed males, respectively; 21 and 40 days, CAP- and FA-exposed females, respectively]. Similar to its putative pathogenesis in humans, CAP exposure-induced premature mortality in Drosophila was also coincided with activation of pro-inflammatory signaling pathways including Jak, Jnk, and Nf-κb and increased systemic oxidative stress. Furthermore, like in humans and mammals, exposure to CAP significantly increased whole-body and circulating glucose levels and increased mRNA expression of Ilp2 and Ilp5 , indicating that CAP exposure induces dysregulated insulin signaling in Drosophila. Similar to effects on humans exposure to CAP leads to premature mortality likely through induction of inflammation-associated signaling, oxidative stress, and metabolic abnormality in Drosophila, strongly supporting that it can be a useful model organism for PM 2.5 toxicity study.

Extreme levels of ambient air pollution adversely impact cardiac and central aortic hemodynamics: the AIRCMD-China study

Ambient air pollution is an independent risk factor for cardiovascular diseases. However, the underlying mechanisms have yet to be fully elucidated. We performed a panel study on 65 nonsmoking patients with metabolic syndrome, with four repeated clinical visits between 2012 and 2013 in Beijing, China. Cardiac and central aortic hemodynamic parameters were measured by pulse wave analyses as subendocardial viability ratio, ejection duration, and central aortic pressure. We also calculated rate-pressure product parameter and collected peripheral blood for analyses. High levels of ambient particulate matter with diameter ≤10 and 2.5 μm (PM₁₀ and PM_2.5), black carbon, sulfur dioxide, and nitrogen dioxide were 121.3, 99.5, 6.5, 24.5, and 59.2 μg/m³, respectively. Short- to medium-term exposures to high levels of ambient air pollution adversely impacted central hemodynamics-derived surrogates of myocardial perfusion and oxygen demand. Each 10 μg/m³ increase in PM_2.5 was associated with significant decreases of 0.67% (95% confidence interval: -2.84, -0.22) in subendocardial viability ratio at moving average 35 days (MA35) and an increase of 0.31 in rate-pressure product (95% confidence interval: 0.03, 0.59) at MA5. In conclusion, our results suggest that impaired myocardial perfusion and increased myocardial oxygen demand may play importantly mechanistic roles in air pollution-attributed cardiovascular diseases.

Bayesian model averaging method for evaluating associations between air pollution and respiratory mortality: a time-series study

OBJECTIVE

To demonstrate an application of Bayesian model averaging (BMA) with generalised additive mixed models (GAMM) and provide a novel modelling technique to assess the association between inhalable coarse particles (PM10) and respiratory mortality in time-series studies.

DESIGN

A time-series study using regional death registry between 2009 and 2010.

SETTING

8 districts in a large metropolitan area in Northern China.

PARTICIPANTS

9559 permanent residents of the 8 districts who died of respiratory diseases between 2009 and 2010.

MAIN OUTCOME MEASURES

Per cent increase in daily respiratory mortality rate (MR) per interquartile range (IQR) increase of PM10 concentration and corresponding 95% confidence interval (CI) in single-pollutant and multipollutant (including NOx, CO) models.

RESULTS

The Bayesian model averaged GAMM (GAMM+BMA) and the optimal GAMM of PM10, multipollutants and principal components (PCs) of multipollutants showed comparable results for the effect of PM10 on daily respiratory MR, that is, one IQR increase in PM10 concentration corresponded to 1.38% vs 1.39%, 1.81% vs 1.83% and 0.87% vs 0.88% increase, respectively, in daily respiratory MR. However, GAMM+BMA gave slightly but noticeable wider CIs for the single-pollutant model (-1.09 to 4.28 vs -1.08 to 3.93) and the PCs-based model (-2.23 to 4.07 vs -2.03 vs 3.88). The CIs of the multiple-pollutant model from two methods are similar, that is, -1.12 to 4.85 versus -1.11 versus 4.83.

CONCLUSIONS

The BMA method may represent a useful tool for modelling uncertainty in time-series studies when evaluating the effect of air pollution on fatal health outcomes.

Traffic-related air pollution is associated with cardio-metabolic biomarkers in general residents

PURPOSE

The study was conducted to explore the mechanisms linking traffic-related air pollution and cardio-metabolic risk.

METHODS

The participants included 371 men and women aged from 45 to 75 in an urban residential area in Shanghai, China. The participants were divided into four categories (≤50, 51-100, 101-200 and >200 m) according to the residential distance to major road. Additionally, the personal fine particulate matter (PM2.5) was measured from 8:00 am to 6:00 pm to assess the PM2.5 exposure in general residents. Then, the continuous subclinical measurements and biological effects related to cardio-metabolic disorders were detected. The generalized linear regression analysis was applied for estimating the adjusted hazards ratio for cardio-metabolic disorders relative to traffic-related air pollution.

RESULTS

The average personal PM2.5 is 111.1 μg/m(3) in the participants living within 50 m to major road, which is significantly higher than the personal PM2.5 (68.2 μg/m(3)) in the participants living more than 200 m away from the major road. The participants living within 50 m to major road compared with those living more than 200 m away have 1.15 times higher of heart rate (HR), 1.95 times higher of fasting insulin, 1.30 times higher of homeostasis model assessment of insulin resistance (HOMA-IR), 1.56 times higher of low-density lipoprotein cholesterol (LDL-C), 8.39 times higher of interleukin 6 (IL-6), 4.30 times higher of augmentation index (AI), 1.60 times higher of systolic blood pressure (SBP) and 1.91 times higher of diastolic blood pressure (DBP). Contrary to the increase in above biological effects, there were 1.06 times lower of low frequency (LF), 1.05 times lower of high frequency (HF), 2.54 times lower of IL-10, 4.61 times lower of nitric oxide (NO), 1.19 times lower of superoxide dismutase (SOD) and 1.85 times lower of total antioxidant capacity (T-AOC). There was no clear exposure-response relationship can be observed in the fasting glucose, LF/HF, cholesterol and high-density lipoprotein (HDL).

CONCLUSION

Long-term exposure to traffic-related air pollution may contribute to the development or exacerbation of cardio-metabolic disorders. The mechanisms linking air pollution and cardio-metabolic disorders may be associated with the increased systemic inflammation and oxidative stress, reduced insulin sensitivity and elevated arterial stiffness and blood pressure.

Extreme Air Pollution Conditions Adversely Affect Blood Pressure and Insulin Resistance: The Air Pollution and Cardiometabolic Disease Study

Mounting evidence supports that fine particulate matter adversely affects cardiometabolic diseases particularly in susceptible individuals; however, health effects induced by the extreme concentrations within megacities in Asia are not well described. We enrolled 65 nonsmoking adults with metabolic syndrome and insulin resistance in the Beijing metropolitan area into a panel study of 4 repeated visits across 4 seasons since 2012. Daily ambient fine particulate matter and personal black carbon levels ranged from 9.0 to 552.5 µg/m(3) and 0.2 to 24.5 µg/m(3), respectively, with extreme levels observed during January 2013. Cumulative fine particulate matter exposure windows across the prior 1 to 7 days were significantly associated with systolic blood pressure elevations ranging from 2.0 (95% confidence interval, 0.3-3.7) to 2.7 (0.6-4.8) mm Hg per SD increase (67.2 µg/m(3)), whereas cumulative black carbon exposure during the previous 2 to 5 days were significantly associated with ranges in elevations in diastolic blood pressure from 1.3 (0.0-2.5) to 1.7 (0.3-3.2) mm Hg per SD increase (3.6 µg/m(3)). Both black carbon and fine particulate matter were significantly associated with worsening insulin resistance (0.18 [0.01-0.36] and 0.22 [0.04-0.39] unit increase per SD increase of personal-level black carbon and 0.18 [0.02-0.34] and 0.22 [0.08-0.36] unit increase per SD increase of ambient fine particulate matter on lag days 4 and 5). These results provide important global public health warnings that air pollution may pose a risk to cardiometabolic health even at the extremely high concentrations faced by billions of people in the developing world today.

A systematic review on the effects of environmental exposure to some organohalogens and phthalates on early puberty

Background:

Early puberty is a common worldwide problem. Different parameters as genetics, metabolic diseases, obesity, as well as environmental factors may affect the age of puberty. This systematic review aims to survey the related literature on the effects of environmental pollutants and especially organohalogens and phthalates on early puberty.

Materials and Methods:

A systematic review of papers published in the English language was completed in January 2014. Studies on the associations of organohalogens and phthalates with the puberty time were included. A literature search was conducted in EMBASE, PubMed, Scopus, ISI Web of Science, and Cochrane Library from 1995 to January 2014; moreover manual search through references of relevant manuscripts was considered. The literature search identified 212 papers, of which 13 papers fulfilled the inclusion criteria of the current study. Two reviewers independently identified relevant papers for potential inclusion and assessed the methodological quality.

Results:

This review included 6572 participants in nine countries from three continents (Europe, North America, and Asia). Different studies determined the effects of pollutants on maturation signs and pubertal stages and confirmed the association of organohalogens and phthalates with early puberty.

Conclusion:

Based on the studied literature, environmental pollutants surround and accumulate in human societies and their adverse health effects are well documented. It can be concluded that organohalogens and phthalates are disturbing the normal process of puberty timing; especially their influence on early maturation in girls should be underscored.

Air Pollution modifies the association between successful and pathological aging throughout the frailty condition

The rapid growth in the number of older adults has many implications for public health, including the need to better understand the risks posed by environmental exposures. Aging leads to a decline and deterioration of functional properties at the cellular, tissue and organ level. This loss of functional properties yields to a loss of homeostasis and decreased adaptability to internal and external stress. Frailty is a geriatric syndrome characterized by weakness, weight loss, and low activity that is associated with adverse health outcomes. Frailty manifests as an age-related, biological vulnerability to stressors and decreased physiological reserves. Ambient air pollution exposure affects human health, and elderly people appear to be particularly susceptible to its adverse effects. The aim of this paper is to discuss the role of air pollution in the modulation of several biological mechanisms involved in aging. Evidence is presented on how air pollution can modify the bidirectional association between successful and pathological aging throughout the frailty conditions.

Association of Roadway Proximity with Fasting Plasma Glucose and Metabolic Risk Factors for Cardiovascular Disease in a Cross-Sectional Study of Cardiac Catheterization Patients

BACKGROUND

The relationship between traffic-related air pollution (TRAP) and risk factors for cardiovascular disease needs to be better understood in order to address the adverse impact of air pollution on human health.

OBJECTIVE

We examined associations between roadway proximity and traffic exposure zones, as markers of TRAP exposure, and metabolic biomarkers for cardiovascular disease risk in a cohort of patients undergoing cardiac catheterization.

METHODS

We performed a cross-sectional study of 2,124 individuals residing in North Carolina (USA). Roadway proximity was assessed via distance to primary and secondary roadways, and we used residence in traffic exposure zones (TEZs) as a proxy for TRAP. Two categories of metabolic outcomes were studied: measures associated with glucose control, and measures associated with lipid metabolism. Statistical models were adjusted for race, sex, smoking, body mass index, and socioeconomic status (SES).

RESULTS

An interquartile-range (990 m) decrease in distance to roadways was associated with higher fasting plasma glucose (β = 2.17 mg/dL; 95% CI: -0.24, 4.59), and the association appeared to be limited to women (β = 5.16 mg/dL; 95% CI: 1.48, 8.84 compared with β = 0.14 mg/dL; 95% CI: -3.04, 3.33 in men). Residence in TEZ 5 (high-speed traffic) and TEZ 6 (stop-and-go traffic), the two traffic zones assumed to have the highest levels of TRAP, was positively associated with high-density lipoprotein cholesterol (HDL-C; β = 8.36; 95% CI: -0.15, 16.9 and β = 5.98; 95% CI: -3.96, 15.9, for TEZ 5 and 6, respectively).

CONCLUSION

Proxy measures of TRAP exposure were associated with intermediate metabolic traits associated with cardiovascular disease, including fasting plasma glucose and possibly HDL-C.

Association of Atmospheric Particulate Matter and Ozone with Gestational Diabetes Mellitus

BACKGROUND

Ambient air pollution has been linked to the development of gestational diabetes mellitus (GDM). However, evidence of the association is very limited, and no study has estimated the effects of ozone.

OBJECTIVE

Our aim was to determine the association of prenatal exposures to particulate matter ≤ 2.5 μm (PM2.5) and ozone (O3) with GDM.

METHODS

We used Florida birth vital statistics records to investigate the association between the risk of GDM and two air pollutants (PM2.5 and O3) among 410,267 women who gave birth in Florida between 2004 and 2005. Individual air pollution exposure was assessed at the woman's home address at time of delivery using the hierarchical Bayesian space-time statistical model. We further estimated associations between air pollution exposures during different trimesters and GDM.

RESULTS

After controlling for nine covariates, we observed increased odds of GDM with per 5-μg/m3 increase in PM2.5 (ORTrimester1 = 1.16; 95% CI: 1.11, 1.21; ORTrimester2 = 1.15; 95% CI: 1.10, 1.20; ORPregnancy = 1.20; 95% CI: 1.13, 1.26) and per 5-ppb increase in O3 (ORTrimester1 = 1.09; 95% CI: 1.07, 1.11; ORTrimester2 = 1.12; 95% CI: 1.10, 1.14; ORPregnancy = 1.18; 95% CI: 1.15, 1.21) during both the first trimester and second trimester as well as the full pregnancy in single-pollutant models. Compared with the single-pollutant model, the ORs for O3 were almost identical in the co-pollutant model. However, the ORs for PM2.5 during the first trimester and the full pregnancy were attenuated, and no association was observed for PM2.5 during the second trimester in the co-pollutant model (OR = 1.02; 95% CI: 0.98, 1.07).

CONCLUSION

This population-based study suggests that exposure to air pollution during pregnancy is associated with increased risk of GDM in Florida, USA.

CITATION

Hu H, Ha S, Henderson BH, Warner TD, Roth J, Kan H, Xu X. 2015. Association of atmospheric particulate matter and ozone with gestational diabetes mellitus. Environ Health Perspect 123:853-859; http://dx.doi.org/10.1289/ehp.1408456.

Air pollution and risk of type 2 diabetes mellitus: a systematic review and meta-analysis

AIM

Whether exposure to relatively high levels of air pollution is associated with diabetes occurrence remains unclear. We sought to assess and quantify the association between exposure to major air pollutants and risk of type 2 diabetes.

METHODS

PubMed and EMBASE databases (through September 2013) were searched using a combination of terms related to exposure to gaseous (NO2 and NOx) or particulate matter pollutants (PM2.5, PM10 and PM10-2.5) and type 2 diabetes. Descriptive and quantitative information were extracted from selected studies. We used random-effects models meta-analysis to derive overall risk estimates per type of pollutant.

RESULTS

We included ten studies (five cross-sectional and five prospective), assessing the effects of air pollutants on the occurrence of diabetes. In prospective investigations, the overall effect on diabetes occurrence was significant for both NO2 (adjusted hazard ratio [HR], 1.13; 95% confidence interval [95%CI], 1.01-1.22; p < 0.001; I(2) = 36.4%, pheterogeneity = 0.208) and PM2.5 (HR, 1.11; 95%CI, 1.03-1.20; p < 0.001; I(2) = 0.0%, pheterogeneity = 0.827). Odds ratios were reported by two cross-sectional studies which revealed similar associations between both NO2 and PM2.5 with type 2 diabetes. Across studies, risk estimates were generally adjusted for age, gender, body mass index and cigarette smoking.

CONCLUSIONS

Available evidence supports a prospective association of main air pollutants with an increased risk for type 2 diabetes. This finding may have implications for population-based strategies to reduce diabetes risk.

Relationships between fine particulate air pollution, cardiometabolic disorders, and cardiovascular mortality

RATIONALE

Growing evidence suggests that long-term exposure to fine particulate matter (PM2.5) air pollution contributes to risk of cardiovascular disease (CVD) morbidity and mortality. There is uncertainty about who are most susceptible. Individuals with underlying cardiometabolic disorders, including hypertension, diabetes mellitus, and obesity, may be at greater risk. PM2.5 pollution may also contribute to cardiometabolic disorders, augmenting CVD risk.

OBJECTIVE

This analysis evaluates relationships between long-term PM2.5 exposure and cardiometabolic disease on risk of death from CVD and cardiometabolic conditions.

METHODS AND RESULTS

Data on 669 046 participants from the American Cancer Society Cancer Prevention Study II cohort were linked to modeled PM2.5 concentrations at geocoded home addresses. Cox proportional hazards regression models were used to estimate adjusted hazards ratios for death from CVD and cardiometabolic diseases based on death-certificate information. Effect modification by pre-existing cardiometabolic risk factors on the PM2.5-CVD mortality association was examined. PM2.5 exposure was associated with CVD mortality, with the hazards ratios (95% confidence interval) per 10 μg/m(3) increase in PM2.5 equal to 1.12 (1.10-1.15). Deaths linked to hypertension and diabetes mellitus (mentioned on death certificate as either primary or contributing cause of death) were also associated with PM2.5. There was no consistent evidence of effect modification by cardiometabolic disease risk factors on the PM2.5-CVD mortality association.

CONCLUSIONS

Pollution-induced CVD mortality risk is observed for those with and without existing cardiometabolic disorders. Long-term exposure may also contribute to the development or exacerbation of cardiometabolic disorders, increasing risk of CVD, and cardiometabolic disease mortality.

Is air quality index associated with cardiometabolic risk factors in adolescents? The CASPIAN-III Study

OBJECTIVE

This study aims to evaluate the association of air quality index (AQI) with cardiometabolic risk factors in a nationally representative sample of healthy adolescents.

METHODS

This nationwide survey was conducted among a stratified multi-stage probability sample of students, aged 10-18 years, from 27 provinces of Iran. Those students with history of any acute or chronic diseases, any medication use, as well as active or passive smoking were not included to the current study. Dietary and physical activity habits were documented by valid questionnaires. Physical examination and blood sampling were conducted under standard protocols. AQI data were obtained from air pollution monitoring sites from the entire country by considering air pollutants concentration, which includes all provincial counties containing different clusters.

RESULTS

The study participants consisted of 1413 students (48.8% boys) with a mean (SD) age of 14.81±2.48 years. The mean AQI level was 285.37±30.11 at national levels. After adjustment for confounding factors including age, sex, and anthropometric measures, as well as for dietary and physical activity habits, multiple linear regressions based on correlation of coefficients of the AQI with cardiometabolic risk factors showed significant positive correlations of AQI with systolic blood pressure, fasting blood glucose, total cholesterol, LDL-cholesterol, and triglycerides, as well as significant negative correlations with HDL-cholesterol. After adjustment for abovementioned confounding factors, binary logistic regressions analyses showed that AQI increased the risk of abnormal levels of some risk factors as elevated levels of systolic blood pressure, total cholesterol, and triglycerides.

CONCLUSION

The associations of low air quality with some cardiometabolic factors in the current survey, although not strong, might be considered as an evidence of the adverse cardiometabolic consequences of exposure to air pollutants in the pediatric age group, and predisposing them to earlier development of non-communicable diseases.

Personal black carbon exposure influences ambulatory blood pressure: air pollution and cardiometabolic disease (AIRCMD-China) study

Few prospective studies have assessed the blood pressure effect of extremely high air pollution encountered in Asia's megacities. The objective of this study was to evaluate the association between combustion-related air pollution with ambulatory blood pressure and autonomic function. During February to July 2012, personal black carbon was determined for 5 consecutive days using microaethalometers in patients with metabolic syndrome in Beijing, China. Simultaneous ambient fine particulate matter concentration was obtained from the Beijing Municipal Environmental Monitoring Center and the US Embassy. Twenty-four-hour ambulatory blood pressure and heart rate variability were measured from day 4. Arterial stiffness and endothelial function were obtained at the end of day 5. For statistical analysis, we used generalized additive mixed models for repeated outcomes and generalized linear models for single/summary outcomes. Mean (SD) of personal black carbon and fine particulate matter during 24 hours was 4.66 (2.89) and 64.2 (36.9) μg/m(3). Exposure to high levels of black carbon in the preceding hours was associated significantly with adverse cardiovascular responses. A unit increase in personal black carbon during the previous 10 hours was associated with an increase in systolic blood pressure of 0.53 mm Hg and diastolic blood pressure of 0.37 mm Hg (95% confidence interval, 0.17-0.89 and 0.10-0.65 mm Hg, respectively), a percentage change in low frequency to high frequency ratio of 5.11 and mean interbeat interval of -0.06 (95% confidence interval, 0.62-9.60 and -0.11 to -0.01, respectively). These findings highlight the public health effect of air pollution and the importance of reducing air pollution.

Ozone induces glucose intolerance and systemic metabolic effects in young and aged Brown Norway rats

Air pollutants have been associated with increased diabetes in humans. We hypothesized that ozone would impair glucose homeostasis by altering insulin signaling and/or endoplasmic reticular (ER) stress in young and aged rats. One, 4, 12, and 24 month old Brown Norway (BN) rats were exposed to air or ozone, 0.25 or 1.0 ppm, 6 h/day for 2 days (acute) or 2 d/week for 13 weeks (subchronic). Additionally, 4 month old rats were exposed to air or 1.0 ppm ozone, 6 h/day for 1 or 2 days (time-course). Glucose tolerance tests (GTT) were performed immediately after exposure. Serum and tissue biomarkers were analyzed 18 h after final ozone for acute and subchronic studies, and immediately after each day of exposure in the time-course study. Age-related glucose intolerance and increases in metabolic biomarkers were apparent at baseline. Acute ozone caused hyperglycemia and glucose intolerance in rats of all ages. Ozone-induced glucose intolerance was reduced in rats exposed for 13 weeks. Acute, but not subchronic ozone increased α2-macroglobulin, adiponectin and osteopontin. Time-course analysis indicated glucose intolerance at days 1 and 2 (2>1), and a recovery 18 h post ozone. Leptin increased day 1 and epinephrine at all times after ozone. Ozone tended to decrease phosphorylated insulin receptor substrate-1 in liver and adipose tissues. ER stress appeared to be the consequence of ozone induced acute metabolic impairment since transcriptional markers of ER stress increased only after 2 days of ozone. In conclusion, acute ozone exposure induces marked systemic metabolic impairments in BN rats of all ages, likely through sympathetic stimulation.