Platelet activation, upregulation of CD11b/ CD18 expression on leukocytes and increase in circulating leukocyte-platelet aggregates in Indian women chronically exposed to biomass smoke

Genetic and nongenetic drivers of platelet reactivity in healthy Tanzanian individuals

BACKGROUND

Platelets play a key role in hemostasis, inflammation, and cardiovascular diseases. Platelet reactivity is highly variable between individuals. The drivers of this variability in populations from Sub-Saharan Africa remain largely unknown.

OBJECTIVES

We aimed to investigate the nongenetic and genetic determinants of platelet reactivity in healthy adults living in a rapidly urbanizing area in Northern Tanzania.

METHODS

Platelet activation and reactivity were measured by platelet P-selectin expression and the binding of fibrinogen in unstimulated blood and after ex vivo stimulation with adenosine diphosphate and PAR-1 and PAR-4 ligands. We then analyzed the associations of platelet parameters with host genetic and nongenetic factors, environmental factors, plasma inflammatory markers, and plasma metabolites.

RESULTS

Only a few associations were found between platelet reactivity parameters and plasma inflammatory markers and nongenetic host and environmental factors. In contrast, untargeted plasma metabolomics revealed a large number of associations with food-derived metabolites, including phytochemicals that were previously reported to inhibit platelet reactivity. Genome-wide single-nucleotide polymorphism genotyping identified 2 novel single-nucleotide polymorphisms (rs903650 and rs4789332) that were associated with platelet reactivity at the genome-wide level (P < 5 × 10-8) as well as a number of variants in the PAR4 gene (F2RL3) that were associated with PAR4-induced reactivity.

CONCLUSION

Our study uncovered factors that determine variation in platelet reactivity in a population in East Africa that is rapidly transitioning to an urban lifestyle, including the importance of genetic ancestry and the gradual abandoning of the traditional East African diet.

Platelet-Leucocyte Aggregates as Novel Biomarkers in Cardiovascular Diseases

Simple Summary

Cardiovascular diseases are the most common cause of death worldwide. Hence, novel biomarkers are urgently needed to improve diagnosis and treatment. Platelet–leucocyte aggregates are conglomerates of platelets and leucocytes and are widely investigated as biomarkers in cardiovascular diseases. Platelet–leucocytes aggregates are present in health, but increase in patients with cardiovascular risk factors and acute or stable coronary syndromes, making them a potential diagnostic marker. Moreover, platelet–leucocyte aggregates predict outcomes after surgery or percutaneous treatment and could be used to monitor antiplatelet therapy. Emerging data about the participation of platelet–leucocyte aggregates in cardiovascular diseases pathogenesis make them an attractive target for novel therapies. Furthermore, simple detection with conventional flow cytometry provides accurate and reproducible results, although requires specific sample handling. The main task for the future is to determine the standardized protocol to measure blood concentrations of platelet–leucocyte aggregates and subsequently establish their normal range in health and disease.

Abstract

Platelet–leucocyte aggregates (PLA) are a formation of leucocytes and platelets bound by specific receptors. They arise in the condition of sheer stress, thrombosis, immune reaction, vessel injury, and the activation of leukocytes or platelets. PLA participate in cardiovascular diseases (CVD). Increased levels of PLA were revealed in acute and chronic coronary syndromes, carotid stenosis cardiovascular risk factors. Due to accessible, available, replicable, quick, and low-cost quantifying using flow cytometry, PLA constitute an ideal biomarker for clinical practice. PLA are promising in early diagnosing and estimating prognosis in patients with acute or chronic coronary syndromes treated by percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). PLA were also a reliable marker of platelet activity for monitoring antiplatelet therapy. PLA consist also targets potential therapies in CVD. All of the above potential clinical applications require further studies to validate methods of assay and proof clinical benefits.

All-Cause Mortality Risk Associated With Solid Fuel Use Among Chinese Elderly People: A National Retrospective Longitudinal Study

Background: The adverse health effects of air pollutants are widely reported, and the elderly are susceptible to toxic environments. This study aimed to evaluate the association between use of solid fuels for cooking and mortality among the elderly. Methods: A total of 5,732 and 3,869 participants from the Chinese Longitudinal Healthy Longevity Survey were enrolled in two (2014 and 2018) and three surveys (2011, 2014, and 2018) of survey. Cooking fuel was divided into clean and solid fuel. Cox proportional hazards models were used to estimate the mortality hazard ratio (HR). Subgroup analyses were performed to assess the potential interaction effect. Results: Among the participants in the 2011-2018 survey, 53% reported using solid fuel. Such group was associated with a 9% increase in mortality risk relative to clean fuel users (HR = 1.09, 95% CI = 1.01-1.18). Among participants in the 2014-2018 survey, 339 reported a switch from solid to clean fuels and they were not at increased mortality risk relative to the 488 people that reported a stable use of clean fuels (HR = 1.14, 95% CI = 0.99-1.31) although the estimated HR was similar to the one for stable solid fuel users (HR = 1.19, 95%CI = 1.04-1.36 n = 509). Interaction and stratified analyses showed that solid fuel use had an impact on mortality in participants who were non-current smokers, had low dietary diversity scores, and were living in areas with high PM2.5 concentrations (>50 μg/m3) and city population below 8 million (P for interaction < 0.05). The association was robust in the three sensitivity analyses. Conclusion: The finding showed a clear association between solid fuel use and mortality among older Chinese, and an even stronger association between risk of mortality and solid fuel use among individuals exposed to high levels of PM2.5.

Biomass Fuel Use and Cardiac Function in Nepali Women

Background

Exposure to household air pollution (HAP) from cooking with biomass fuel affects billions of people. We hypothesized that HAP from woodsmoke, compared to other household fuels, was associated with adverse cardiovascular outcomes, of which there have been few studies.

Methods

A cross-sectional study was completed in 299 females aged 40-70 years in Kaski District, Nepal, during 2017-18. All participants underwent a standard 12-lead ECG, ankle and brachial systolic blood pressure measurement, and 2D color and Doppler echocardiography. Current stove type was confirmed by inspection. Blood pressure, height, and weight were measured using a standardized protocol. Hypertension was defined as ≥140/90 mmHg or prior diagnosis. Hemoglobin A1c (HbA1c) was obtained, with diabetes mellitus defined as a prior diagnosis or HbA1C ≥ 6.5%. We used adjusted linear and logistic multivariable regressions to examine the relationship of stove type with cardiac structure and function.

Results

The majority of women primarily used liquified petroleum gas (LPG) stoves (65%), while 12% used biogas, and 23% used wood-burning cook-stoves. Prevalence of major cardiovascular risk factors was 35% with hypertension, 19% with diabetes mellitus, and 15% current smokers. After adjustment, compared to LPG, wood stove use was associated with increased indexed left atrial volume (β = 3.15, 95% CI 1.22 to 5.09) and increased indexed left ventricular end diastolic volume (β = 7.97, 95% CI 3.11 to 12.83). There was no association between stove type and systemic hypertension, left ventricular mass, systolic dysfunction, diastolic dysfunction, pulmonary hypertension, abnormal ankle-brachial index, or clinically significant ECG abnormalities.

Conclusion

Biomass fuel use was associated with increased indexed left atrial volume and increased indexed left ventricular diastolic volume in Nepali women, suggesting subclinical adverse cardiac remodeling from HAP in this cross-sectional study. We did not find evidence of an association with hypertension or typical cardiac sequelae of hypertension. Future studies to confirm these results are needed.

Coronary heart disease, hypertension and use of biomass fuel among women: comparative cross-sectional study

OBJECTIVES

To explore the associations of hypertension and coronary heart disease (CHD) with use of biomass fuel for cooking.

DESIGN

Comparative cross-sectional study.

SETTING

Rural villages in Sindh, Pakistan.

PARTICIPANTS

Women aged ≥40 years who had used biomass fuel for cooking for at least the last year (n=436), and a comparison group (n=414) who had cooked only with non-biomass fuel during the last year were recruited through door-to-door visits. None of those who were invited to take part declined.

PRIMARY AND SECONDARY OUTCOME MEASURES

Hypertension was determined from blood pressure measurements and use of medication. CHD was assessed by three measures: history of angina (Rose angina questionnaire), previous history of 'heart attack', and definite or probable changes of CHD on ECG. Potentially confounding risk factors were ascertained by questionnaire and anthropometry. Associations of hypertension and CHD with use of biomass and other risk factors were assessed by logistic regression, and summarised by ORs with 95% CIs.

RESULTS

After adjustment for potential confounders, there was no association of hypertension (OR: 1.0, 95% CI 0.8 to 1.4) angina (OR: 1.0, 95% CI 0.8 to 1.4), heart attack (OR: 1.2, 95% 0.7 to 2.2) or ECG changes of CHD (OR: 0.8, 95% CI 0.6 to 1.2) with current use of biomass for cooking. Nor were any associations apparent when analyses were restricted to long-term (≥10 years) users and non-users of biomass fuel.

CONCLUSIONS

A linked air monitoring study indicated substantially higher airborne concentrations of fine particulate matter in kitchens where biomass was used for cooking. It is possible that associations with CHD and hypertension were missed because most of the comparison group had used biomass for cooking at some time in the past, and risk remains elevated for many years after last exposure.

Lead exposure is associated with risk of impaired coagulation in preschool children from an e-waste recycling area

Environmental lead exposure leads to various deleterious effects on multiple organs and systems, including the hematopoietic system. To explore the effects of lead exposure on platelet indices in preschool children from an informal, lead-contaminated electronic waste (e-waste) recycling area, we collected venous blood samples from 466 preschool children (331 from an e-waste area (Guiyu) and 135 from a non-e-waste area (Haojiang)). Child blood lead levels (BLLs) were determined by graphite furnace atomic absorption spectrophotometry, while platelet indices were quantified using a Sysmex XT-1800i hematology analyzer. Higher blood lead levels are observed in e-waste lead-exposed preschool children. Significant relationships between high blood lead levels (exceeding current health limits) and elevated platelet count (PLT), plateletcrit (PCT), mean platelet volume (MPV), and platelet large cell ratio (P-LCR) were also uncovered. Furthermore, the median PLT and PCT levels of children from the exposed group both exceeded the respective recommended maximum reference range value, whereas the reference group did not. Location of child residence in Guiyu and BLLs were both risk factors related to platelet indices. These results suggest that high blood lead exposure from e-waste recycling may increase the risk of an amplified coagulation process through the activation of platelets in preschool children.

Approximation of personal exposure to fine particulate matters (PM2.5) during cooking using solid biomass fuels in the kitchens of rural West Bengal, India

More than 85% of the rural Indian households use traditional solid biofuels (SBFs) for daily cooking. Burning of the easily available unprocessed solid fuels in inefficient earthen cooking stoves produce large quantities of particulate matters. Smaller particulates, especially with aerodynamic diameter of 2.5 μm or less (PM_2.5), largely generated during cooking, are considered to be health damaging in nature. In the present study, kitchen level exposure of women cooks to fine particulate matters during lunch preparation was assessed considering kitchen openness as surrogate to the ventilation condition. Two-way ANCOVA analysis considering meal quantity as a covariate revealed no significant interaction between the openness and the seasons explaining the variability of the personal exposure to the fine particulate matters in rural kitchen during cooking. Multiple linear regression analysis revealed the openness as the only significant predictor for personal exposure to the fine particulate matters. In the present study, the annual average fine particulate matter exposure concentration was found to be 974 μg m^-3.

Biomass fuel smoke exposure was associated with adverse cardiac remodeling and left ventricular dysfunction in Peru

While household air pollution from biomass fuel combustion has been linked to cardiovascular disease, the effects on cardiac structure and function have not been well described. We sought to determine the association between biomass fuel smoke exposure and cardiac structure and function by transthoracic echocardiography. We identified a random sample of urban and rural residents living in the high-altitude region of Puno, Peru. Daily biomass fuel use was self-reported. Participants underwent transthoracic echocardiography. Multivariable linear regression was used to examine the relationship of biomass fuel use with echocardiographic measures of cardiac structure and function, adjusting for age, sex, height, body mass index, diabetes, physical activity, and tobacco use. One hundred and eighty-seven participants (80 biomass fuel users and 107 non-users) were included in this analysis (mean age 59 years, 58% women). After adjustment, daily exposure to biomass fuel smoke was associated with increased left ventricular internal diastolic diameter (P=.004), left atrial diameter (P=.03), left atrial area (four-chamber) (P=.004) and (two-chamber) (P=.03), septal E' (P=.006), and lateral E' (P=.04). Exposure to biomass fuel smoke was also associated with worse global longitudinal strain in the two-chamber view (P=.01). Daily biomass fuel use was associated with increased left ventricular size and decreased left ventricular systolic function by global longitudinal strain.

Ambient fine particles (PM2.5 ) attenuate collagen-induced platelet activation through interference of the PLCγ2/Akt/GSK3β signaling pathway

AIMS

It has been proven that carbon nanoparticles or diesel exhaust particles stimulate platelet activation. However, the effect of fine particle matter (PM_2.5 ) on platelet activation remains unknown, which motivates this study.

METHODS

PM_2.5 samples were collected in an urban area of Zhengzhou, China. To study the morphological characteristics and the mass concentrations of trace elements of PM_2.5 samples, a filed-emission scanning electron microscope, the Image-J software, and an inductively coupled plasma mass spectrometry were used. Washed human platelets or platelet-rich-plasma were used to study the effect of PM_2.5 on platelet aggregation, P-selectin expression, or platelet signaling pathways. The cytotoxicity in platelets exposed to PM_2.5 was evaluated by a lactate dehydrogenase assay kit. In addition, platelet adhesion and spreading were studied on collagen-coated surfaces in stable conditions.

RESULTS

The filed-emission scanning electron microscope scanning showed that PM_2.5 samples varied in shape and size distributions. The mean equivalent spherical diameter of these particles was 1.97 ± 0.04 μm, of which 82.40% were particles with equivalent spherical diameters of less than 2.5 μm. The mass concentration of Ca was higher than that of other elements. The other elements followed the trend of Al>Fe>Zn>Mg>Pb>K>Mn>Cu>Ti>Ba>As>Sr>Sn>Sb>Cd>B>Se>Mo>Ag>Ni>TI>V>Co. Furthermore, pretreatment of PM_2.5 significantly inhibited rather than potentiated collagen-induced platelet aggregation and P-selectin expression, whereas it had no significant effect on ADP-induced platelet aggregation and P-selectin expression. The lactate dehydrogenase analysis showed trivial cytotoxic effect of PM_2.5 exposure on platelets. Pretreatment of PM_2.5 inhibited platelet adhesion on immobilized collagen-coated surfaces; however, it almost did not impact the platelet spreading. Immunoblotting analysis indicated that PM_2.5 reduced collagen-induced phosphorylation of phospholipase C gamma-2 (PLCγ2) at Tyr759, Akt at Ser473, and glycogen synthase kinase 3β (GSK3β) at Ser9.

CONCLUSIONS

PM_2.5 attenuated collagen-induced platelet aggregation, α-granule secretion and adhesion, with the potential mechanism of impairing PLCγ2, Akt, and GSK3β signaling. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 530-540, 2017.

Plasma asymmetric dimethylarginine (ADMA) levels in Mexican women exposed to polycyclic aromatic hydrocarbons (PAHs): A preliminary study

Recent studies indicate that exposure to environmental pollutants (as polycyclic aromatic hydrocarbons) is a very important risk factor for development of cardiovascular diseases (CVDs). Correspondingly, in recent times asymmetric dimethylarginine (ADMA) has been proposed as a new and meaningful biomarker predictor for the risk of CVDs. Therefore, the objective of this study was to evaluate plasma ADMA concentrations in Mexican women (n=155) exposed to polycyclic aromatic hydrocarbons (PAHs). Urinary 1-hydroxypyrene [(1-OHP), exposure biomarker for PAHs] levels were quantified using a high performance liquid chromatography (HPLC) technique and plasma ADMA concentrations were analyzed using a commercially available ELISA kit. Urinary 1-OHP levels in all women assessed ranged from <LOD to 8.80μmol/mol creatinine. Regarding plasma ADMA concentrations, the mean levels ranged from 0.66 to 1.00μmol/L. Moreover, a significantly relationship was found between plasma ADMA concentrations and urinary 1-OHP levels (p=0.005; r=0.390). In conclusion, the results showed in this study demonstrated that the urinary 1-OHP levels were significant predictors of plasma ADMA concentrations in Mexican women exposed to PAHs. Although with due caution regarding the low representativeness of the present screening, it can be considered as a preliminary work to perform prospective studies including greater number of individuals and focusing in a more complete characterization of the effects produced by PAHs exposure on cardiovascular health.

Chronic exposure to biomass fuel smoke and markers of endothelial inflammation

Indoor smoke exposure may affect cardiovascular disease (CVD) risk via lung-mediated inflammation, oxidative stress, and endothelial inflammation. We sought to explore the association between indoor smoke exposure from burning biomass fuels and a selected group of markers for endothelial inflammation. We compared serum concentrations of amyloid A protein, E-selectin, soluble intercellular adhesion molecule 1 (ICAM-1) and VCAM-1, von Willebrand factor (vWF), and high-sensitivity C-reactive protein (hs-CRP) in 228 biomass-exposed vs. 228 non-exposed participants living in Puno, Peru. Average age was 56 years (s.d. = 13), average BMI was 26.5 kg/m(2) (s.d. = 4.4), 48% were male, 59.4% completed high school, and 2% reported a physician diagnosis of CVD. In unadjusted analysis, serum levels of soluble ICAM-1 (330 vs. 302 ng/ml; P < 0.001), soluble VCAM-1 (403 vs. 362 ng/ml; P < 0.001), and E-selectin (54.2 vs. 52.7 ng/ml; P = 0.05) were increased in biomass-exposed vs. non-exposed participants, respectively, whereas serum levels of vWF (1148 vs. 1311 mU/ml; P < 0.001) and hs-CRP (2.56 vs. 3.12 mg/l; P < 0.001) were decreased, respectively. In adjusted analyses, chronic exposure to biomass fuels remained positively associated with serum levels of soluble ICAM-1 (P = 0.03) and VCAM-1 (P = 0.05) and E-selectin (P = 0.05), and remained negatively associated with serum levels of vWF (P = 0.02) and hs-CRP (P < 0.001). Daily exposure to biomass fuel smoke was associated with important differences in specific biomarkers of endothelial inflammation and may help explain accelerated atherosclerosis among those who are chronically exposed.

Coronary heart disease and household air pollution from use of solid fuel: a systematic review

BACKGROUND

Evidence is emerging that indoor air pollution (IAP) from use of solid fuels for cooking and heating may be an important risk factor for coronary heart disease (CHD).

SOURCES OF DATA

We searched the Ovid Medline, Embase Classic, Embase and Web of Science databases from inception through to June 12, 2015, to identify reports of primary epidemiological research concerning the relationship of CHD to IAP from solid fuel, the likely magnitude of any increase in risk, and potential pathogenic mechanisms.

AREAS OF AGREEMENT

The current balance of epidemiological evidence points to an increased risk of CHD from IAP as a consequence of using solid, and especially biomass, fuels for cooking and heating. Relative risks from long-term exposure could be 2- to 4-fold.

AREAS OF CONTROVERSY

The evidence base is still limited, and although an association of CHD with such IAP from solid fuel is consistent with the known hazards from smoking, environmental tobacco smoke and ambient air pollution, and supported by evidence of effects on inflammatory processes, atherosclerosis and blood pressure, it requires confirmation by larger and more robust studies.

GROWING POINTS

The completion of two relatively small case-control studies on CHD and IAP from use of biomass fuel demonstrates the feasibility of such research, and is an encouragement to further, larger studies using similar methods.

AREAS TIMELY FOR DEVELOPING RESEARCH

The need for such research is particularly pressing because the incidence of CHD in developing countries is rising, and IAP may interact synergistically with the risk factors that are driving that increase. Furthermore, relatively cheap methods are available to reduce IAP from use of solid fuels, and there are indications from intervention studies that these may impact beneficially on CHD as well as other diseases caused by such pollution.

[Air pollution]

Short-term exposure to particulate matter (PM) air pollution is associated with an increased cardiovascular mortality. Chronic exposure to PM is also associated with cardiovascular risk. Myocardial infarction and heart failure are the most common cardiovascular events associated with PM pollution. The pathophysiological mechanisms related to PM pollution are inflammation, thrombosis, vasomotion abnormalities, progression of atherosclerosis, increased blood pressure, and cardiac remodeling. A decrease in PM exposure may be particularly beneficial in subjects with a high cardiovascular risk.

Assessment of vascular function in Mexican women exposed to polycyclic aromatic hydrocarbons from wood smoke

The use of solid fuels for cooking and heating is likely to be the largest source of indoor air pollution on a global scale; these fuels emit substantial amounts of toxic pollutants such as polycyclic aromatic hydrocarbons (PAHs) when used in simple cooking stoves (such as open "three-stone" fires). Moreover, indoor air pollution from biomass fuels is considered an important risk factor for human health. The aim of this study was to evaluate the relationship between exposure to PAHs from wood smoke and vascular dysfunction; in a group of Mexican women that use biomass combustion as their main energy source inside their homes. We used 1-hydroxypyrene (1-OHP) as an exposure biomarker to PAHs and it was assessed using high performance liquid chromatography. The endothelium-dependent vasodilation was assessed through a vascular reactivity compression test performed with a pneumatic cuff under visualization of the brachial artery using high resolution ultrasonography (HRU). Assessment of the carotid intima-media thickness (CIMT) was used as an atherosclerosis biomarker (also assessed using HRU); and clinical parameters such as anthropometry, blood pressure, glucose, triglycerides, total cholesterol, HDL cholesterol, LDL cholesterol, among others were also evaluated. The mean concentration of urinary 1-OHP found in exposed women was 0.46±0.32μmol/mol Cr (range: 0.086-1.23μmol/mol Cr). Moreover, vascular dysfunction (diminished endothelium dependent vasodilation) was found in 45% of the women participating in the study. Association between vascular function and 1-OHP levels was found to be significant through a logistic regression analysis (p=0.034; r(2)=0.1329). Furthermore, no association between CIMT and clinical parameters, urinary 1-OHP levels or vascular dysfunction was found. Therefore, with the information obtained in this study, we advocate for the need to implement programs to reduce the risk of exposure to PAHs in communities that use biomass fuels as a main energy source.

Respiratory symptoms, lung function decrement and chronic obstructive pulmonary disease in pre-menopausal Indian women exposed to biomass smoke

BACKGROUND

The impact of chronic exposure to smoke from biomass burning on respiratory health has been examined.

METHODS

Six-hundred and eighty-one non-smoking women (median age 35 years) from eastern India who cook exclusively with biomass (wood, dung and crop residues) and 438 age-matched women from similar neighborhood who cook with liquefied petroleum gas (LPG) were examined. Pulmonary function test was done by spirometry. The concentrations of particulate matter having diameter of < 10 µm (PM10) and < 2.5 µm (PM2.5) in indoor air was measured by real-time aerosol monitor.

RESULTS

Compared with LPG users, biomass users had greater prevalence of upper (50.9 versus 28.5%) and lower respiratory symptoms (71.8 versus 30.8%) and dyspnea (58.4 versus 19.9%). They showed reduction in all parameters measured by spirometer especially in mid-expiratory volume. PM10 and PM2.5 concentration in biomass using kitchen were 2-3-times more than LPG-using kitchen, and the decline in spirometry values was positively associated PM10 and PM2.5 levels in indoor air after controlling education, family income and kitchen location as potential confounders. Overall, 29.7% of biomass users and 16.4% of LPG users had deficient lung function, and restrictive type of deficiency was predominant. Chronic obstructive pulmonary disease (COPD) was diagnosed in 4.6% of biomass and 0.9% of LPG users. Women who predominantly used dung cake and did not possess separate kitchen had poorer lung function.

CONCLUSION

Cumulative exposure to biomass smoke causes lung function decrement and facilitates COPD development even in non-smoking and relatively young pre-menopausal women.

Indoor and outdoor exposure to ultrafine, fine and microbiologically derived particulate matter related to cardiovascular and respiratory effects in a panel of elderly urban citizens

To explore associations of exposure to ambient and indoor air particulate and bio-aerosol pollutants with cardiovascular and respiratory disease markers, we utilized seven repeated measurements from 48 elderly subjects participating in a 4-week home air filtration study. Microvascular function (MVF), lung function, blood leukocyte counts, monocyte adhesion molecule expression, C-reactive protein, Clara cell protein (CC16) and surfactant protein-D (SPD) were examined in relation to exposure preceding each measurement. Exposure assessment included 48-h urban background monitoring of PM10, PM2.5 and particle number concentration (PNC), weekly measurements of PM2.5 in living- and bedroom, 24-h measurements of indoor PNC three times, and bio-aerosol components in settled dust on a 2-week basis. Statistically significant inverse associations included: MVF with outdoor PNC; granulocyte counts with PM2.5; CD31 expression with dust fungi; SPD with dust endotoxin. Significant positive associations included: MVF with dust bacteria; monocyte expression of CD11 with PM2.5 in the bedroom and dust bacteria and endotoxin, CD31 expression with dust serine protease; serum CC16 with dust NAGase. Multiple comparisons demand cautious interpretation of results, which suggest that outdoor PNC have adverse effects on MVF, and outdoor and indoor PM2.5 and bio-aerosols are associated with markers of inflammation and lung cell integrity.

Cardiovascular and lung function in relation to outdoor and indoor exposure to fine and ultrafine particulate matter in middle-aged subjects

This cross-sectional study investigated the relationship between exposure to airborne indoor and outdoor particulate matter (PM) and cardiovascular and respiratory health in a population-based sample of 58 residences in Copenhagen, Denmark. Over a 2-day period indoor particle number concentrations (PNC, 10-300 nm) and PM2.5 (aerodynamic diameter<2.5 μm) were monitored for each of the residences in the living room, and outdoor PNC (10-280 nm), PM2.5 and PM10 (aerodynamic diameter<10 μm) were monitored at an urban background station in Copenhagen. In the morning, after the 2-day monitoring period, we measured microvascular function (MVF) and lung function and collected blood samples for biomarkers related to inflammation, in 78 middle-aged residents. Bacteria, endotoxin and fungi were analyzed in material from electrostatic dust fall collectors placed in the residences for 4 weeks. Data were analyzed using linear regression with the generalized estimating equation approach. Statistically significant associations were found between indoor PNC, dominated by indoor use of candles, and lower lung function, the prediabetic marker HbA1c and systemic inflammatory markers observed as changes in leukocyte differential count and expression of adhesion markers on monocytes, whereas C-reactive protein was significantly associated with indoor PM2.5. The presence of indoor endotoxin was associated with lower lung function and expression of adhesion markers on monocytes. An inverse association between outdoor PNC and MVF was also statistically significant. The study suggests that PNC in the outdoor environment may be associated with decreased MVF, while PNC, mainly driven by candle burning, and bioaerosols in the indoor environment may have a negative effect on lung function and markers of systemic inflammation and diabetes.

A feasibility study of the association of exposure to biomass smoke with vascular function, inflammation, and cellular aging

BACKGROUND

Biomass smoke at higher concentrations is associated with respiratory symptoms and, after years of exposure, increased risk of respiratory disorders in adults, but its effects on cardiovascular diseases are not well characterized, particularly compared with other pollution sources like tobacco smoke or traffic.

METHODS

We conducted a cross-sectional study and enrolled 25 women living in rural Sichuan, China. We measured integrated 24-h personal exposure to fine particulate matter (PM2.5) and black carbon, and measured PM2.5 and black carbon in their kitchens. We assessed participants' brachial and central blood pressure and arterial stiffness using pulse wave analysis, and analyzed dried blood spot and buccal cell samples for C-reactive protein and relative telomere length. We also evaluated the difference in these physiological and biomarker measures between individuals with high (≥median) versus low (<median) PM2.5 exposure using multivariate regression.

RESULTS

Geometric mean 24-h PM2.5 and black carbon exposures were 61 µg/m(3) (95% CI: 48, 78) and 3.2 µg/m(3) (95% CI: 2.3, 4.5), respectively. Average kitchen PM2.5 and black carbon concentrations were only moderately correlated with personal exposures (PM2.5: r=0.41; black carbon: r=0.63), although they had similar means. Women in the high and low exposure groups were similar in age, obesity, socioeconomic status, salt intake, and physical activity. Women in the high PM2.5 exposure group had higher mean brachial systolic blood pressure (SBP; difference=4.6 mmHg, 95% CI -7.8, 16.9), central SBP (difference=3.1 mmHg, 95% CI: -8.4, 14.5), central pulse pressure (difference=4.1 mmHg; 95% CI: -4.2, 12.4), and augmentation index (difference=2.8%, 95% CI: -1.6, 7.2). High exposed women had 43% shorter telomere length (95% CI: -113, 28) than that of women in the low exposure group. There were no differences in pulse wave velocity or C-reactive protein between the two exposure groups. None of the results was statistically significant.

CONCLUSIONS

Our results suggest that it is feasible to measure markers of vascular function and biomarkers of inflammation and oxidative stress in field studies of biomass smoke. Although many of the associations were in the expected direction, larger studies would be needed to establish the effects.

Biomarkers of oxidative stress and inflammation after wood smoke exposure in a reconstructed Viking Age house

Exposure to particles from combustion of wood is associated with respiratory symptoms, whereas there is limited knowledge about systemic effects. We investigated effects on systemic inflammation, oxidative stress and DNA damage in humans who lived in a reconstructed Viking Age house, with indoor combustion of wood for heating and cooking. The subjects were exposed to high indoor concentrations of PM2.5 (700-3,600 µg/m(3)), CO (10.7-15.3 ppm) and NO2 (140-154 µg/m(3)) during a 1-week stay. Nevertheless, there were unaltered levels of genotoxicity, determined as DNA strand breaks and formamidopyrimidine DNA glycosylase and oxoguanine DNA glycosylase 1 sensitive sites in peripheral blood mononuclear cells. There were also unaltered expression levels of OGG1, HMOX1, CCL2, IL8, and TNF levels in leukocytes. In serum, there were unaltered levels of C-reactive protein, IL6, IL8, TNF, lactate dehydrogenase, cholesterol, triglycerides, and high-density lipoproteins. The wood smoke exposure was associated with decreased serum levels of sICAM-1, and a tendency to decreased sVCAM-1 levels. There was a minor increase in the levels of circulating monocytes expressing CD31, whereas there were unaltered expression levels of CD11b, CD49d, and CD62L on monocytes after the stay in the house. In conclusion, even a high inhalation exposure to wood smoke was associated with limited systemic effects on markers of oxidative stress, DNA damage, inflammation, and monocyte activation.

An indoor air filtration study in homes of elderly: cardiovascular and respiratory effects of exposure to particulate matter

BACKGROUND

Exposure to particulate air pollution increases respiratory and cardiovascular morbidity and mortality, especially in elderly, possibly through inflammation and vascular dysfunction.

METHODS

We examined potential beneficial effects of indoor air filtration in the homes of elderly, including people taking vasoactive drugs.Forty-eight nonsmoking subjects (51 to 81 years) in 27 homes were included in this randomized, double-blind, crossover intervention study with consecutive two-week periods with or without the inclusion of a high-efficiency particle air filter in re-circulating custom built units in their living room and bedroom. We measured blood pressure, microvascular and lung function and collected blood samples for hematological, inflammation, monocyte surface and lung cell damage markers before and at day 2, 7 and 14 during each exposure scenario.

RESULTS

The particle filters reduced the median concentration of PM2.5 from approximately 8 to 4 μg/m3 and the particle number concentration from 7669 to 5352 particles/cm3. No statistically significant effects of filtration as category were observed on microvascular and lung function or the biomarkers of systemic inflammation among all subjects, or in the subgroups taking (n = 11) or not taking vasoactive drugs (n = 37). However, the filtration efficacy was variable and microvascular function was within 2 days significantly increased with the actual PM2.5 decrease in the bedroom, especially among 25 subjects not taking any drugs.

CONCLUSION

Substantial exposure contrasts in the bedroom and no confounding by drugs appear required for improved microvascular function by air filtration, whereas no other beneficial effect was found in this elderly population.

A systematic review of air pollution as a risk factor for cardiovascular disease in South Asia: limited evidence from India and Pakistan

Cardiovascular diseases (CVD) are major contributors to mortality and morbidity in South Asia. Chronic exposure to air pollution is an important risk factor for cardiovascular diseases, although the majority of studies to date have been conducted in developed countries. Both indoor and outdoor air pollution are growing problems in developing countries in South Asia yet the impact on rising rates of CVD in these regions has largely been ignored. We aimed to assess the evidence available regarding air pollution effects on CVD and CVD risk factors in lower income countries in South Asia. A literature search was conducted in PubMed and Web of Science. Our inclusion criteria included peer-reviewed, original, empirical articles published in English between the years 1990 and 2012, conducted in the World Bank South Asia region (Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka). This resulted in 30 articles. Nine articles met our inclusion criteria and were assessed for this systematic review. Most of the studies were cross-sectional and examined measured particulate matter effects on CVD outcomes and indicators. We observed a bias as nearly all of the studies were from India. Hypertension and CVD deaths were positively associated with higher particulate matter levels. Biomarkers of oxidative stress such as increased levels of P-selection expressing platelets, depleted superoxide dismutase and reactive oxygen species generation as well as elevated levels of inflammatory-related C-reactive protein, interleukin-6 and interleukin-8 were also positively associated with biomass use or elevated particulate matter levels. An important outcome of this investigation was the evidence suggesting important air pollution effects regarding CVD risk in South Asia. However, too few studies have been conducted. There is as an urgent need for longer term investigations using robust measures of air pollution with different population groups that include a wider range of air pollutants and outcomes, including early indicators of CVD. These regions are facing burdens from increasing urbanization, air pollution and populations, generally weaker health infrastructure, aging populations and increased incidence of non-communicable diseases, included CVD. The extent to which the problem of air pollution and CVD will impact these countries will depend largely on the information available to inform policy and programs, which are still lacking, political will as well as social and economic development.

The emerging role of outdoor and indoor air pollution in cardiovascular disease

Outdoor and indoor air pollution poses a significant cardiovascular risk, and has been associated with atherosclerosis, the main underlying pathology in many cardiovascular diseases. Although, it is well known that exposure to air pollution causes pulmonary disease, recent studies have shown that cardiovascular health consequences of air pollution generally equal or exceed those due to pulmonary diseases. The objective of this article is to evaluate the current evidence on the emerging role of environmental air pollutions in cardiovascular disease, with specific focus on the types of air pollutants and mechanisms of air pollution-induced cardiotoxicity. Published literature on pollution was systematically reviewed and cited in this article. It is hoped that this review will provide a better understanding of the harmful cardiovascular effects induced by air pollution exposure. This will help to bring a better understanding on the possible preventive health measures and will also serve regulatory agencies and researchers. In addition, elucidating the biological mechanisms underlying the link between air pollution and cardiovascular disease is an essential target in developing novel pharmacological strategies aimed at decreasing adverse effects of air pollution on cardiovascular system.

Chronic exposure to biomass fuel is associated with increased carotid artery intima-media thickness and a higher prevalence of atherosclerotic plaque

BACKGROUND

Biomass fuels are used for cooking in the majority of rural households worldwide. While their use is associated with an increased risk of lung diseases and all-cause mortality, the effects on cardiovascular disease (CVD) are not well characterised. Exposure to biomass fuel smoke has been associated with lung-mediated inflammation and oxidative stress, which may increase the risk of atherosclerosis as evaluated by carotid intima-media thickness (CIMT), carotid atherosclerotic plaque prevalence and blood pressure.

METHODS

A cross-sectional study was performed in 266 adults aged ≥35 years in Puno, Peru (3825 m above sea level). We stratified participants by their long-term history of exposure to clean fuel (n=112) or biomass fuel (n=154) and measured 24 h indoor particulate matter (PM2.5) in a random subset (n=84). Participants completed questionnaires and underwent a clinical assessment, laboratory analyses and carotid artery ultrasound. The main outcome measures were CIMT, carotid plaque and blood pressure.

RESULTS

The groups were similar in age and gender. The biomass fuel group had greater unadjusted mean CIMT (0.66 vs 0.60 mm; p<0.001), carotid plaque prevalence (26% vs 14%; p=0.03), systolic blood pressure (118 vs 111 mm Hg; p<0.001) and median household PM2.5 (280 vs 14 µg/m(3); p<0.001). In multivariable regression, the biomass fuel group had greater mean CIMT (mean difference=0.03 mm, 95% CI 0.01 to 0.06; p=0.02), a higher prevalence of carotid plaques (OR=2.6, 95% CI 1.1 to 6.0; p=0.03) and higher systolic blood pressure (mean difference=9.2 mm Hg, 95% CI 5.4 to 13.0; p<0.001).

CONCLUSIONS

Chronic exposure to biomass fuel was associated with increased CIMT, increased prevalence of atherosclerotic plaques and higher blood pressure. These findings identify biomass fuel use as a risk factor for CVD, which may have important global health implications.

Impact of a cleaner-burning cookstove intervention on blood pressure in Nicaraguan women

Few studies have evaluated the cardiovascular-related effects of indoor biomass burning or the role of characteristics such as age and obesity status, in this relationship. We examined the impact of a cleaner-burning cookstove intervention on blood pressure among Nicaraguan women using an open fire at baseline; we also evaluated heterogeneity of the impact by subgroups of the population. We evaluated changes in systolic and diastolic blood pressure from baseline to post-intervention (range: 273-383 days) among 74 female cooks. We measured indoor fine particulate matter (PM(2.5); N = 25), indoor carbon monoxide (CO; N = 32), and personal CO (N = 30) concentrations. Large mean reductions in pollutant concentrations were observed for all pollutants; for example, indoor PM(2.5) was reduced 77% following the intervention. However, pollution distributions (baseline and post-intervention) were wide and overlapping. Although substantial reductions in blood pressure were not observed among the entire population, a 5.9 mmHg reduction [95% confidence interval (CI): -11.3, -0.4] in systolic blood pressure was observed among women aged 40 or more years and a 4.6 mmHg reduction (95% CI: -10.0, 0.8) was observed among obese women. Results from this study provide an indication that certain subgroups may be more likely to experience improvements in blood pressure following a cookstove intervention.

The biological effects of individual-level PM(2.5) exposure on systemic immunity and inflammatory response in traffic policemen

BACKGROUND

Ambient fine-particle particulate matter (PM2.5) exposure is associated with the decline in pulmonary function, prevalence of coronary heart disease and incidence of myocardial infarction. The study is to observe the effects of ambient PM2.5 on the cardiovascular system and to explore the potential inflammatory and immune mechanisms.

METHODS

The subjects included 110 traffic policemen in Shanghai, China, who were aged 25-55 years. Two-times continuous 24 h individual-level PM2.5 measurements were performed in winter and summer, respectively. The inflammatory marker (high-sensitivity C-reactive protein, hs-CRP), immune parameters (IgA, IgG, IgM and IgE) and lymphocyte profiles (CD4 T cells, CD8 T cells, CD4/CD8 T cells) were measured in blood. The associations between individual-level PM2.5 and inflammatory marker and immune parameters were analysed by multiple linear regression.

RESULTS

The average concentration of 24 h personal PM2.5 for participants was 116.98 μg/m(3) and 86.48 μg/m(3) in winter and summer, respectively. In the main analysis, PM2.5 exposure is associated with the increases in hs-CRP of 1.1%, IgG of 6.7%, IgM of 11.2% and IgE of 3.3% in participants, and decreases in IgA of 4.7% and CD8 of 0.7%, whereas we found no statistical association in CD4 T cells and CD4/CD8 T cells. In the adjusted model, the results showed that the increase of PM2.5 was associated with the changes of inflammatory markers and immune markers both in winter and summer.

CONCLUSIONS

Traffic policeman have been a high-risk group suffering inflammatory response or immune injury because of the high exposure to PM2.5. These findings provided new insight into the mechanisms linking ambient PM2.5 and inflammatory and immune response.

In-home solid fuel use and cardiovascular disease: a cross-sectional analysis of the Shanghai Putuo study

BACKGROUND

Although recent research evidence suggests an association between household air pollution from solid fuel use, such as coal or biomass, and cardiovascular events such as hypertension, little epidemiologic data are available concerning such exposure effects on cardiovascular endpoints other than hypertension. We explored the association between in-home solid fuel use and self-reported diagnoses of cardiovascular endpoints, such as hypertension, coronary heart disease (CHD), stroke, and diabetes.

METHODS

We analyzed 14,068 Chinese adults, aged 18 years and older. Odds ratios (OR) and the corresponding 95% confidence intervals (CI) were estimated using logistic regression models for the risk of each outcome after adjusting for potential confounders.

RESULTS

The use of solid fuel in home was significantly associated with an increased risk for hypertension (OR 1.70, 95% CI 1.40 to 2.07), CHD (OR 2.58, 95% CI 1.53 to 4.32), and diabetes (OR 2.48, 95% CI 1.59 to 3.86), after adjusting for potential confounders. Compared with individuals in the lowest tertile of the duration of solid fuel exposure, those in the highest tertile of the duration of solid fuel exposure had an increased odds of hypertension (OR 1.73, 95% CI 1.45 to 2.06), stroke (OR 1.87, 95% CI 1.03 to 3.38), and diabetes (OR 3.18, 95% CI 2.11 to 4.78).

CONCLUSIONS

Our data suggest that in-home solid fuel exposure maybe associated with increased risk for hypertension, CHD, stroke, and diabetes in the Chinese adult population. Further large-scale longitudinal studies are warranted to confirm these findings.

Platelet-leukocyte interactions in thrombosis

Activated platelets may adhere to leukocytes and form circulating mixed aggregates. The latter are considered a reliable marker of a prothrombotic state and are associated with several cardiovascular conditions. The molecular mechanisms responsible of this cellular interaction include a central role of platelet P-selectin and of P-selectin glycoprotein ligand-1 (PSGL-1), its counter receptor on leukocytes in a signaling cascade, resulting in the activation of the beta-2 integrin Mac-1 and in the firm adhesion between the two cell types. The interaction of P-selectin with PSGL-1 also induces upregulation of leukocyte tissue factor, biosynthesis of several cytokines and other inflammatory reactions, thereby contributing to the thrombotic progression. In this review the main determinants of mixed aggregate formation, the heritability component, the major pathological conditions associated with higher levels of mixed aggregates in the circulation will be discussed. Besides current anti-platelet or antithrombotic drugs, natural compounds, such as the polyphenols present in vegetable foods and red wine, have been tested for their inhibitory effect on mixed aggregate formation. The promising results shown by studies in vitro and in experimental animal models, remain to be carefully investigated in humans. Platelet-leukocyte aggregates provide a novel link between inflammation and thrombosis, two central processes in atherogenesis. A better understanding of the role of platelet-leukocyte interactions in athero-thrombosis will be instrumental for the progress of prevention and treatment of ischaemic cardiovascular disease.

The effect of air pollution on haemostasis

Ambient environmental air pollutants include gaseous and particulate components. In polluted air, especially particulate matter seems responsible for cardiovascular complications: It consists of a heterogeneous mixture of solid and liquid particles with different diameters ranging from large thoracic to ultrafine particles, with a diameter <100 nm. Ultrafines can penetrate deeply into the lung to deposit in the alveoli. Cardiovascular manifestations result both from short-term and long-term exposure and have been linked to interference with the autonomic nervous system, direct translocation into the systemic circulation, pulmonary inflammation and oxidative stress. Thrombotic complications associated with air pollution comprise arterial and probably venous thrombogenicity. This review describes the existing epidemiological and experimental evidence to explain the rapid induction of myocardial infarction within 1-2 hours after exposure to polluted air and advances several explanations as to why more chronic exposure will lead to enhanced venous thrombogenicity. Mechanisms such as platelet activation, endothelial dysfunction, coagulation factor changes and microvesicle production are discussed.

A baseline evaluation of traditional cook stove smoke exposures and indicators of cardiovascular and respiratory health among Nicaraguan women

Biomass-derived indoor air pollution has been associated with increased risks of respiratory diseases; however, relatively few studies have examined the cardiovascular effects of biomass burning. We measured 48-hour indoor fine particulate matter and indoor and personal carbon monoxide (CO) concentrations in 124 households using open-fire cook stoves in Nicaragua. We also examined the cross-sectional relationship of air pollution and health. High air pollutant concentrations with considerable variability were measured. Nonsignificant elevations in systolic blood pressure were associated with increases in CO concentrations. These associations were stronger among obese participants; an 8.51 mmHg (95% confidence interval [CI]: 3.06, 13.96) increase in systolic blood pressure per 24 ppm increase in 48-hour average indoor CO levels was observed. Although the cross-sectional design of this study limits the interpretation, we observed evidence of a relationship between indoor air pollution and blood pressure and heart rate, two indicators of cardiovascular health.

Evaluation of mucociliary clearance among women using biomass and clean fuel in a periurban area of Chennai: A preliminary study

Background:

Nasal mucociliary clearance (NMC) plays a crucial role in the defense of the airways against inhaled substances and is affected by various factors. The effect of particulate matter on NMC in women using biomass fuel has not been well studied.

Aim:

This cross-sectional study was conducted to assess the NMC time in biomass fuel users and compare it with that of clean fuel users.

Materials and Methods:

NMC time and Peak Expiratory Flow Rate (PEFR) were determined in women of age ranging from 18 to 45 years using biomass fuel (n=30) and clean fuel (n=30). The time taken to perceive the sweet taste, following placement of saccharin 1 cm behind the anterior end of inferior turbinate was recorded as NMC time. PEFR was measured using mini-Wright peak flow meter. Comparison between groups was analyzed using t-test and ANOVA in R statistical software.

Results:

NMC time was significantly prolonged in biomass fuel users (765.8 ± 378.16 s) in comparison to clean fuel users (545.4 ± 215.55 s). PEFR was significantly reduced (319.3 l/min) in biomass fuel users compared to clean fuel users (371.7 l/min). Women from lower socioeconomic status, lower literacy status, older undernourished women and women cooking for>15 years had prolonged Saccharin Transit Time (STT) and reduced PEFR.

Conclusions:

This study highlights the effects of indoor air pollution on respiratory defense mechanism. This simple noninvasive, inexpensive, screening test can be used as an early indicator of respiratory damage caused by exposure to air pollutants.

Hypertension with elevated levels of oxidized low-density lipoprotein and anticardiolipin antibody in the circulation of premenopausal Indian women chronically exposed to biomass smoke during cooking

This study aims to investigate whether indoor air pollution (IAP) from biomass fuel use was associated with hypertension, platelet hyperactivity, and elevated levels of oxidized low-density lipoprotein (oxLDL) and anticardiolipin antibody (aCL). We enrolled 244 biomass fuel-using (median age 34 year) and 236 age-matched control women who cooked with liquefied petroleum gas (LPG). Enzyme-linked immunosorbent assay was used to measure oxLDL in plasma and aCL in serum, flow cytometry for P-selectin expression on platelet and reactive oxygen species (ROS) generation by leukocytes, aggregometry for platelet aggregation, spectrophotometry for superoxide dismutase (SOD) in erythrocytes, and laser photometer for particulate matter <10 and 2.5 μm in diameter (PM(10) and PM(2.5), respectively) in cooking areas. Biomass users had three times more particulate pollution in kitchen, had higher prevalence of hypertension (29.5 vs. 11.0% in control, P < 0.05), elevated oxLDL (170.6 vs. 45.9 U/l; P < 0.001), platelet P-selectin expression (9.1% vs. 2.4%), platelet aggregation (23.2 vs. 15.9 Ohm), raised aCL IgG (28.7% vs. 2.1%), IgM (8.6% of vs. 0.4%), and ROS (44%) but depleted (13%) SOD. After controlling potential confounders, the changes were positively associated with PM(10) and PM(2.5) in indoor air, suggesting a positive association between IAP and increased cardiovascular risk.

PRACTICAL IMPLICATIONS

The study showing high risk of developing cardiovascular diseases (CVD) among poor, underprivileged women in their reproductive ages in rural India is important from public health perspectives. It may motivate the government and the regulatory agencies of the country to take a serious note of the indoor air pollution (IAP) from biomass fuel use as it threatens the health of millions of women, children, and the elderly who mostly stay indoor. We hope the findings will strengthen the demand for setting up a standard for indoor air quality in the country in the line of national ambient air quality standard. The findings may also inspire the authorities to take measures for the reduction in IAP by improving housing, kitchen ventilation, and cook stoves. Moreover, the parameters used in this study can be utilized for large, population-based studies to identify women at a higher risk of developing CVD so that medical intervention can be taken at the formative stage of a disease.

Particulate matter air pollution and cardiovascular disease: An update to the scientific statement from the American Heart Association

In 2004, the first American Heart Association scientific statement on "Air Pollution and Cardiovascular Disease" concluded that exposure to particulate matter (PM) air pollution contributes to cardiovascular morbidity and mortality. In the interim, numerous studies have expanded our understanding of this association and further elucidated the physiological and molecular mechanisms involved. The main objective of this updated American Heart Association scientific statement is to provide a comprehensive review of the new evidence linking PM exposure with cardiovascular disease, with a specific focus on highlighting the clinical implications for researchers and healthcare providers. The writing group also sought to provide expert consensus opinions on many aspects of the current state of science and updated suggestions for areas of future research. On the basis of the findings of this review, several new conclusions were reached, including the following: Exposure to PM <2.5 microm in diameter (PM(2.5)) over a few hours to weeks can trigger cardiovascular disease-related mortality and nonfatal events; longer-term exposure (eg, a few years) increases the risk for cardiovascular mortality to an even greater extent than exposures over a few days and reduces life expectancy within more highly exposed segments of the population by several months to a few years; reductions in PM levels are associated with decreases in cardiovascular mortality within a time frame as short as a few years; and many credible pathological mechanisms have been elucidated that lend biological plausibility to these findings. It is the opinion of the writing group that the overall evidence is consistent with a causal relationship between PM(2.5) exposure and cardiovascular morbidity and mortality. This body of evidence has grown and been strengthened substantially since the first American Heart Association scientific statement was published. Finally, PM(2.5) exposure is deemed a modifiable factor that contributes to cardiovascular morbidity and mortality.

Air pollution and hospitalization for venous thromboembolic disease in Chile

BACKGROUND

Ambient air pollution is a risk factor for stroke and myocardial infarction, possibly because of alterations in coagulation that influence the arterial circulation. Whether air pollution influences diseases associated with peripheral venous thrombogenesis remains largely unknown.

OBJECTIVES

To determine the association between air pollution and venous thromboembolic disease (VTE) in a sample of the general population.

METHODS

A time-series analysis was used to test the association between daily air pollution and VTE hospitalizations in Santiago between 2001 and 2005. Results were adjusted for long-term trends, day of the week and average daily humidex.

RESULTS

From a population of 5.4 million, there were, on average, 2.3 admissions for VTE per day. Pooled estimates of relative risk (RR) [95% confidence interval (CI)] of hospitalization for venous disease were: 1.07 (1.05, 1.09) for a 58.4 p.p.b. increase in ozone (O(3)); 1.06 (1.02, 1.09) for a 5.85 p.p.b. increase in sulphur dioxide (SO(2)); 1.08 (1.03, 1.12) for a 29.25 microg/m(3) increase in nitrogen dioxide (NO(2)); and 1.05 (1.03, 1.06) for a 20.02 microg/m(3) increase in particulate matter < or = 2.5 microm in mean aerodynamic diameter (PM(2.5)). For pulmonary embolism (PE) results were: 1.10 (1.07, 1.13) for O(3); 1.05 (1.02, 1.08) for SO(2); 1.07 (1.04, 1.09) for NO(2); and 1.05(1.03, 1.06) for PM(2.5), respectively.

CONCLUSION

Air pollution appears to be a risk factor for venous thrombosis and PE, a disease with a significant fatality rate.

Impact of improved cookstoves on indoor air pollution and adverse health effects among Honduran women

Elevated indoor air pollution levels due to the burning of biomass in developing countries are well established. Few studies have quantitatively assessed air pollution levels of improved cookstoves and examined these measures in relation to health effects. We conducted a cross-sectional survey among 79 Honduran women cooking with traditional or improved cookstoves. Carbon monoxide and fine particulate matter (PM(2.5)) levels were assessed via indoor and personal monitoring. Pulmonary function and respiratory symptoms were ascertained. Finger-stick blood spot samples were collected to measure C-reactive protein (CRP) concentrations. The use of improved stoves was associated with 63% lower levels of personal PM(2.5), 73% lower levels of indoor PM(2.5), and 87% lower levels of indoor carbon monoxide as compared to traditional stoves. Women using traditional stoves reported symptoms more frequently than those using improved stoves. There was no evidence of associations between cookstove type or air quality measures with lung function or CRP.

Chronic residential exposure to particulate matter air pollution and systemic inflammatory markers

BACKGROUND

Long-term exposure to urban air pollution may accelerate atherogenesis, but mechanisms are still unclear. The induction of a low-grade systemic inflammatory state is a plausible mechanistic pathway.

OBJECTIVES

We analyzed the association of residential long-term exposure to particulate matter (PM) and high traffic with systemic inflammatory markers.

METHODS

We used baseline data from the German Heinz Nixdorf Recall Study, a population-based, prospective cohort study of 4,814 participants that started in 2000. Fine PM [aerodynamic diameter <or= 2.5 microm (PM(2.5))] exposure based on a small-scale dispersion and chemistry transport model was assigned to each home address. We calculated distances between residences and major roads. Long-term exposure to air pollution (annual PM(2.5) and distance to high traffic) and concentration of inflammatory markers [high-sensitivity C-reactive protein (hs-CRP) and fibrinogen] on the day of the baseline visit were analyzed with sex-stratified multiple linear regression, controlling for individual-level risk factors.

RESULTS

In the adjusted analysis, a cross-sectional exposure difference of 3.91 microg/m(3) in PM(2.5) (interdecile range) was associated with increases in hs-CRP of 23.9% [95% confidence interval (CI), 4.1 to 47.4%] and fibrinogen of 3.9% (95% CI, 0.3 to 7.7%) in men, whereas we found no association in women. Chronic traffic exposure was not associated with inflammatory markers. Short-term exposures to air pollutants and temperature did not influence the results markedly.

CONCLUSIONS

Our study indicates that long-term residential exposure to high levels of PM(2.5) is associated with systemic inflammatory markers in men. This might provide a link between air pollution and coronary atherosclerosis.

Adverse cardiovascular effects of air pollution

Air pollution is increasingly recognized as an important and modifiable determinant of cardiovascular disease in urban communities. Acute exposure has been linked to a range of adverse cardiovascular events including hospital admissions with angina, myocardial infarction, and heart failure. Long-term exposure increases an individual's lifetime risk of death from coronary heart disease. The main arbiter of these adverse health effects seems to be combustion-derived nanoparticles that incorporate reactive organic and transition metal components. Inhalation of this particulate matter leads to pulmonary inflammation with secondary systemic effects or, after translocation from the lung into the circulation, to direct toxic cardiovascular effects. Through the induction of cellular oxidative stress and proinflammatory pathways, particulate matter augments the development and progression of atherosclerosis via detrimental effects on platelets, vascular tissue, and the myocardium. These effects seem to underpin the atherothrombotic consequences of acute and chronic exposure to air pollution. An increased understanding of the mediators and mechanisms of these processes is necessary if we are to develop strategies to protect individuals at risk and reduce the effect of air pollution on cardiovascular disease.

Diesel exhaust inhalation increases thrombus formation in man

AIMS

Although the mechanism is unclear, exposure to traffic-derived air pollution is a trigger for acute myocardial infarction (MI). The aim of this study is to investigate the effect of diesel exhaust inhalation on platelet activation and thrombus formation in men.

METHODS AND RESULTS

In a double-blind randomized crossover study, 20 healthy volunteers were exposed to dilute diesel exhaust (350 microg/m(3)) and filtered air. Thrombus formation, coagulation, platelet activation, and inflammatory markers were measured at 2 and 6 h following exposure. Thrombus formation was measured using the Badimon ex vivo perfusion chamber. Platelet activation was assessed by flow cytometry. Compared with filtered air, diesel exhaust inhalation increased thrombus formation under low- and high-shear conditions by 24% [change in thrombus area 2229 microm(2), 95% confidence interval (CI) 1143-3315 microm(2), P = 0.0002] and 19% (change in thrombus area 2451 microm(2), 95% CI 1190-3712 microm(2), P = 0.0005), respectively. This increased thrombogenicity was seen at 2 and 6 h, using two different diesel engines and fuels. Diesel exhaust also increased platelet-neutrophil and platelet-monocyte aggregates by 52% (absolute change 6%, 95% CI 2-10%, P = 0.01) and 30% (absolute change 3%, 95% CI 0.2-7%, P = 0.03), respectively, at 2 h following exposure compared with filtered air.

CONCLUSION

Inhalation of diesel exhaust increases ex vivo thrombus formation and causes in vivo platelet activation in man. These findings provide a potential mechanism linking exposure to combustion-derived air pollution with the triggering of acute MI.