Zhijing Lin

Size-fractionated particulate air pollution and circulating biomarkers of inflammation, coagulation, and vasoconstriction in a panel of young adults.

Background: Short-term associations between size-fractionated particulate air pollution and circulating biomarkers are not well established, especially in developing countries with high levels of particulate matter (PM). Methods: We designed a panel study involving 34 healthy young adults to evaluate acute effects of size-fractionated PM on 13 circulating biomarkers of inflammation, coagulation, and vasoconstriction. We measured real-time, size-fractionated number concentrations of PM (aerodynamic diameters from 0.25 to 10 &mgr;m, mass concentrations of PM < 10 &mgr;m) over four follow-up measurements. The short-term associations between size-fractionated PM and biomarkers were assessed using linear mixed effect models. Results: We found positive associations between short-term exposure to PM and 10 biomarkers. PM with smaller size had stronger associations. The size fractions with the strongest associations were 0.25–0.40 &mgr;m for number concentrations and <1 &mgr;m for mass concentrations. For example, an interquartile range increase in 24-hour-average number concentrations of PM0.25–0.40 was associated with a 7%–32% increase in biomarkers of inflammation, 34%–68% of blood coagulation, and 45% of vasoconstriction. Similar estimates were found for mass concentrations of PM1. Furthermore, our results demonstrated an apparent acute effect on circulating biomarkers, even 2 hours after exposure. The effects were strongest within the first 12–24 hours, and effects on inflammation occurred more quickly than on coagulation and vasoconstriction. Conclusions: Our results provided potentially vital insights into the size and temporal characteristics of PM that could modify subclinical cardiovascular effects. These findings may have implications on disease prevention and environmental regulation in China.

Personal exposure to fine particulate matter and blood pressure: A role of angiotensin converting enzyme and its DNA methylation.

BACKGROUND The underlying intermediate mechanisms about the association between fine particulate matter (PM2.5) air pollution and blood pressure (BP) were unclear. Few epidemiological studies have explored the potential mediation effects of angiotensin-converting enzyme (ACE) and its DNA methylation. METHODS We designed a longitudinal panel study with 4 follow-ups among 36 healthy college students in Shanghai, China from December 17, 2014 to July 11, 2015. We measured personal real-time exposure to PM2.5, serum ACE level, and blood methylation of ACE gene and the repetitive elements. We applied linear mixed-effects models to examine the effects of PM2.5 on ACE protein, DNA methylation and BP markers. Furthermore, we conducted mediation analyses to evaluate the potential pathways. RESULTS An interquartile range increase (26.78μg/m(3)) in 24-h average exposure to PM2.5 was significantly associated with 1.12 decreases in ACE average methylation (%5mC), 13.27% increase in ACE protein, and increments of 1.13mmHg in systolic BP, 0.66mmHg in diastolic BP and 0.82mmHg in mean arterial pressure. ACE hypomethylation mediated 11.78% (P=0.03) of the elevated ACE protein by PM2.5. Increased ACE protein accounted for 3.90~13.44% (P=0.35~0.68) of the elevated BP by PM2.5. Repetitive-element methylation was also decreased but did not significantly mediate the association between PM2.5 and BP. CONCLUSIONS This investigation provided strong evidence that short-term exposure to PM2.5 was significantly associated with BP, ACE protein and ACE methylation. Our findings highlighted a possible involvement of ACE and ACE methylation in the effects of PM2.5 on elevating BP.

Cardiovascular Benefits of Wearing Particulate-Filtering Respirators: A Randomized Crossover Trial.

Background: Practical approaches to protect individuals from ambient particulate matter (PM) are urgently needed in developing countries. Evidence on the health benefits of wearing particulate-filtering respirators is limited. Objectives: We evaluated the short-term cardiovascular health effects of wearing respirators in China. Methods: A randomized crossover trial was performed in 24 healthy young adults in Shanghai, China in 2014. The subjects were randomized into two groups and wore particulate-filtering respirators for 48 hr alternating with a 3-week washout interval. Heart rate variability (HRV) and ambulatory blood pressure (BP) were continuously monitored during the 2nd 24 hr in each intervention. Circulating biomarkers were measured at the end of each intervention. Linear mixed-effect models were applied to evaluate the effects of wearing respirators on health outcomes. Results: During the intervention periods, the mean daily average concentration of PM with an aerodynamic diameter < 2.5 μm (PM2.5) was 74.2 μg/m3. Compared with the absence of respirators, wearing respirators was associated with a decrease of 2.7 mmHg [95% confidence interval (CI): 0.1, 5.2 mmHg] in systolic BP and increases of HRV parameters, including 12.5% (95% CI: 3.8%, 21.2%) in high frequency (HF) power, 10.9% (95% CI: 1.8%, 20.0%) in the root mean square of the successive differences, and 22.1% (95% CI: 3.6%, 40.7%) in the percentage of normal RR intervals with duration > 50 msec different from the previous normal RR interval (pNN50). The presence of respirators was also associated with a decrease of 7.8% (95% CI: 3.5%, 12.1%) in the ratio of low frequency (LF)/HF power. Conclusions: Short-term wearing of particulate-filtering respirators may produce cardiovascular benefits by improving autonomic nervous function and reducing BP. Citation: Shi J, Lin Z, Chen R, Wang C, Yang C, Cai J, Lin J, Xu X, Ross JA, Zhao Z, Kan H. 2017. Cardiovascular benefits of wearing particulate-filtering respirators: a randomized crossover trial. Environ Health Perspect 125:175–180; http://dx.doi.org/10.1289/EHP73

Possible Mediation by Methylation in Acute Inflammation Following Personal Exposure to Fine Particulate Air Pollution

Air pollution may increase cardiovascular and respiratory risk through inflammatory pathways, but evidence for acute effects has been weak and indirect. Between December 2014 and July 2015, we enrolled 36 healthy, nonsmoking college students for a panel study in Shanghai, China, a city with highly variable levels of air pollution. We measured personal exposure to particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5) continuously for 72 hours preceding each of 4 clinical visits that included phlebotomy. We measured 4 inflammation proteins and DNA methylation at nearby regulatory cytosine-phosphate-guanine (CpG) loci. We applied linear mixed-effect models to examine associations over various lag times. When results suggested mediation, we evaluated methylation as mediator. Increased PM2.5 concentration was positively associated with all 4 inflammation proteins and negatively associated with DNA methylation at regulatory loci for tumor necrosis factor alpha (TNF-α) and soluble intercellular adhesion molecule-1. A 10-μg/m3 increase in average PM2.5 during the 24 hours preceding blood draw corresponded to a 4.4% increase in TNF-α and a statistically significant decrease in methylation at one of the two studied candidate CpG loci for TNF-α. Epigenetics may play an important role in mediating effects of PM2.5 on inflammatory pathways.

Home Dampness Signs in Association with Asthma and Allergic Diseases in 4618 Preschool Children in Urumqi, China-The Influence of Ventilation/Cleaning Habits

There is an increasing prevalence of childhood asthma and allergic diseases in mainland of China. Few studies investigated the indoor dampness, ventilation and cleaning habits and their interrelationship with childhood asthma and allergic diseases. A large-scale cross-sectional study was performed in preschool children in Urumqi, China. Questionnaire was used to collect information on children’s health, home dampness and ventilation/cleaning (V/C) habits. Multiple logistic regressions were applied to analyze the associations between childhood asthma/allergic diseases and each sign of home dampness, dampness levels, each V/C habit and total V/C scores. The associations between dampness and health were further performed by strata analyses in two groups with low and high V/C scores. Totally 4618(81.7%) of 5650 children returned the questionnaire. Reports on home dampness were most common for water condensation on windows (20.8%) followed by damp beddings (18.0%). The most common ventilation measure was the use of exhaust fan in bathroom (59.3%), followed by daily home cleaning (48.3%), frequently putting beddings to sunshine (29.9%) and frequently opening windows in winter (8.4%). There were positive associations between the 6 signs of home dampness and children’s health particularly the symptoms last 12 months. By comparing with the reference dampness level (dampness scored 0), both the low dampness (scored 1~2) level and the high dampness level (scored 3~6) showed significantly increasing associations with childhood symptoms. There were crude negative associations between V/C habits and childhood health but not significant adjusting for home dampness levels. The risks of home dampness on children’s health were lower in the group with higher V/C score but the differences were not statistically significant. Home dampness is a potential risk factor for childhood asthma and allergic symptoms in preschool children in Urumqi, China. No significant effects were observed for ordinary home ventilation and cleaning habits in reducing the risks of home dampness on childhood asthma and allergic diseases in Urumqi, China.

Ambient carbon monoxide and cardiovascular mortality: a nationwide time-series analysis in 272 cities in China

BACKGROUND Evidence of the acute health effects of ambient carbon monoxide air pollution in developing countries is scarce and mixed. We aimed to evaluate short-term associations between carbon monoxide and daily cardiovascular disease mortality in China. METHODS We did a nationwide time-series analysis in 272 major cities in China from January, 2013, to December, 2015. We extracted daily cardiovascular disease mortality data from Chinas Disease Surveillance Points system. Data on daily carbon monoxide concentrations for each city were obtained from the National Urban Air Quality Real-time Publishing Platform. City-specific associations between carbon monoxide concentrations and daily mortality from cardiovascular disease, coronary heart disease, and stroke were estimated with over-dispersed generalised linear models. Bayesian hierarchical models were used to obtain national and regional average associations. Exposure-response association curves and potential effect modifiers were evaluated. Two-pollutant models were fit to evaluate the robustness of the effects of carbon monoxide on cardiovascular mortality. FINDINGS The average annual mean carbon monoxide concentration in these cities from 2013 to 2015 was 1·20 mg/m3, ranging from 0·43 mg/m3 to 2·45 mg/m3. For a 1 mg/m3 increase in average carbon monoxide concentrations on the present day and previous day (lag 0-1), we observed significant increments in mortality of 1·12% (95% posterior interval [PI] 0·42-1·83) from cardiovascular disease, 1·75% (0·85-2·66) from coronary heart disease, and 0·88% (0·07-1·69) from stroke. These associations did not vary substantially by city, region, and demographic characteristics (age, sex, and level of education), and the associations for cardiovascular disease and coronary heart disease were robust to the adjustment of criteria co-pollutants. We did not find a threshold below which carbon monoxide exposure had no effect on cardiovascular disease mortality. INTERPRETATION This analysis is, to our knowledge, the largest study done in a developing country, and provides robust evidence of the association between short-term exposure to ambient carbon monoxide and increased cardiovascular disease mortality, especially coronary heart disease mortality. FUNDING Public Welfare Research Program.

Fine particulate matter constituents and blood pressure in patients with chronic obstructive pulmonary disease: A panel study in Shanghai, China.

Objective: The evidence is limited about the potentially different health effects of various chemical constituents of fine particulate matter (PM2.5). We thus assessed the acute effects of various chemical constituents of PM2.5 on blood pressure (BP). Methods: We performed a longitudinal panel study with six repeated visits in 28 urban residents with chronic obstructive pulmonary disease in Shanghai, China from May to July, 2014. Twelve (43%) of them took antihypertensive medications. We measured resting BP by using a mercury sphygmomanometer and monitored real‐time concentrations of PM2.5 constituents at a nearby site. Based on the linear mixed‐effects model, we evaluated the effects of 10 major constituents in PM2.5 on BP, using a single‐constituent model and a constituent‐residual model after accounting for the multicollinearity. Results: We obtained a total of 168 pairs of effective BP measurements during the study period. There are moderate or high correlations among various PM2.5 constituents. An interquartile range increase of PM2.5 (19.1 &mgr;g/m3) was associated with increments of 1.90 mmHg [95% confidence interval (CI): 0.66, 3.13] in systolic BP, 0.68 mmHg (95%CI: −0.02, 1.37) in diastolic BP and 1.23 mmHg (95%CI: 0.19, 2.29) in pulse pressure. Some constituents of PM2.5, including organic carbon, elemental carbon, nitrate and ammonium, were robustly associated with elevated BP after controlling for total PM2.5 mass and accounting for multi‐collinearity. Two constituents (magnesium and calcium) were associated with decreased BP. Conclusions: Organic carbon, elemental carbon, nitrate and ammonium may be mainly responsible for elevated BP from a short‐term exposure to PM2.5. Graphical abstract: Figure. No Caption available. HighlightsA short‐term exposure to PM2.5 was significantly associated with elevated BP levels.Most constituents of PM2.5 were associated with increased BP in single‐constituent model.OC, EC, NO3−, and NH4+ were robustly positively associated with the increased BP.The association between PM2.5 and BP was statistically significant only at lag 0 day.

Associations between short-term exposure to ambient sulfur dioxide and increased cause-specific mortality in 272 Chinese cities

BACKGROUND Ambient sulfur dioxide (SO2) remains a major air pollutant in developing countries, but epidemiological evidence about its health effects was not abundant and inconsistent. OBJECTIVES To evaluate the associations between short-term exposure to SO2 and cause-specific mortality in China. METHODS We conducted a nationwide time-series analysis in 272 major Chinese cities (2013-2015). We used the over-dispersed generalized linear model together with the Bayesian hierarchical model to analyze the data. Two-pollutant models were fitted to test the robustness of the associations. We conducted stratification analyses to examine potential effect modifications by age, sex and educational level. RESULTS On average, the annual-mean SO2 concentrations was 29.8 μg/m3 in 272 cities. We observed positive and associations of SO2 with total and cardiorespiratory mortality. A 10 μg/m3 increase in two-day average concentrations of SO2 was associated with increments of 0.59% in mortality from total non-accidental causes, 0.70% from total cardiovascular diseases, 0.55% from total respiratory diseases, 0.64% from hypertension disease, 0.65% from coronary heart disease, 0.58% from stroke, and 0.69% from chronic obstructive pulmonary disease. In two-pollutant models, there were no significant differences between single-pollutant model and two-pollutant model estimates with fine particulate matter, carbon monoxide and ozone, but the estimates decreased substantially after adjusting for nitrogen dioxide, especially in South China. The associations were stronger in warmer cities, in older people and in less-educated subgroups. CONCLUSIONS This nationwide study demonstrated associations of daily SO2 concentrations with increased total and cardiorespiratory mortality, but the associations might not be independent from NO2.

Estimation of personal ozone exposure using ambient concentrations and influencing factors

Evidence is limited regarding whether ambient monitoring can properly represent personal ozone exposure. We conducted a longitudinal panel study to measure personal exposure to ozone using real-time personal ozone monitors. Corresponding ambient ozone concentrations and possible influencing factors (meteorological conditions and activity patterns) were also collected. We used linear mixed-effect models to analyze personal-ambient ozone concentration associations and possible influencing factors. Ambient ozone concentrations were around two to three times higher than personal ozone (43.1 μg/m3 on average) and their correlations were weak with small slopes (0.35) and marginal R square (RM2) values (0.24). Larger RM2 values were found under high temperature (>29.5 °C), low humidity (<62.1%), good ventilation conditions (>4 h) and for individuals spent longer time outdoors (>0.6 h). In final model, personal ozone exposure was positively associated with ambient concentrations and ventilation conditions, but inversely correlated with ambient temperature and humidity. The models explained >50% of personal ozone concentration variabilities. Our results highlight that ambient ozone concentration alone is not a suitable surrogate for individual exposure assessment. Meteorological conditions (temperature and humidity) and activity patterns (windows opening and outdoor activities) that affecting personal ozone exposure should be taken into account.

Effects of ambient temperature on lung function in patients with chronic obstructive pulmonary disease: A time-series panel study

BACKGROUND Limited evidence concerns the associations between ambient temperature and lung function and the results are mixed. OBJECTIVE To evaluate the associations between temperature variations and daily fluctuations in pulmonary function in chronic obstructive pulmonary disease (COPD) patients. METHODS We designed a time-series panel study of 28 male urban COPD patients with repeated daily lung function measurements from December 2012 to May 2013 in Shanghai, China. We used a linear mixed-effect model combined with a distributed lag model to estimate the cumulative effects of temperature on morning/evening pulmonary function tests (PFTs), including peak expiratory flow (PEF) and forced expiratory volume in 1-s (FEV1), while adjusting for within-subject correlations, individual characteristics, time trends and air pollution levels. RESULTS We obtained a total of 8618 pairs of morning PFTs and 8528 pairs of evening PFTs. The associations between daily mean temperature and PEF were inverted U-shaped with both low and high temperatures significantly reducing morning and evening PEF. Compared with the referent temperature (16°C), the low temperature (1st percentile, -1°C) would result in cumulative decreases of 32.20L/min in morning PEF and 21.15L/min in evening PEF over lags of two weeks. The corresponding decrements at the same lag associated with high temperature (99th percentile, 25°C) were 38.10L/min in morning PEF and 27.08L/min in evening PEF. There were no statistically significant changes in morning or evening FEV1. CONCLUSIONS This time-series panel study provided robust evidence that both low and high temperatures were significantly associated with decrements in pulmonary function, particularly in PEF.