Impact of Using Pre- and Post-Bronchodilator Spirometry Reference Values in a Chinese Population.

RATIONALE: Spirometry reference equations that are derived from a large, nationally representative, general population are warranted in China and the impact of using pre- and post-BD spirometry reference values has yet to be assessed in Chinese populations. OBJECTIVES: To present both the pre-BD and post-BD spirometry reference values for Chinese adults using the China Pulmonary Health (CPH) study. METHODS: A reference population of 17969 healthy, non-smoking participants in the CPH study was used to calculate the pre- and post-BD reference values for the forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC. Both pre- and post-BD reference values were applied to the entire CPH population (50991 individuals) to illustrate the divergence between the use of references in determining the disease prevalence and severity grading. MEASUREMENTS AND MAIN RESULTS: The prevalence of airflow limitation was 5.36% using pre-BD reference and 8.02% using the post-BD reference. Individuals who had post-BD FEV1/FVC below post-BD but higher than pre-BD reference values were found to have significantly higher rates of self-reported respiratory symptoms, and significantly lower values in spirometry indicators than those above post-BD reference values. An additional 3.51% of participants were identified as grade II-IV COPD using the post-BD FEV1 predicted values. CONCLUSION: This study generated and applied pre- and post-bronchodilator spirometry reference values in a nationally representative Chinese adult population. Post-BD reference values may serve as an additional criterion in identifying individuals at risk for obstructive pulmonary diseases, its diagnostic and prognostic values should be further investigated.

[A Review of Comparative Studies on Exposure Levels of Air Pollutants Among Different Modes of Transportation in China's Cities].

Urban traffic is closely related to the daily life of the public,and air pollution in the traffic microenvironment has become a public health problem that cannot be ignored.This paper reviews the comparative studies of air pollutant exposure levels among different modes of transportation in multiple cities in China.By comparing the exposure levels of pollutants among different modes of transportation,this paper provides a reference for protecting the health of the public in daily transportation and selecting targeted control measures.

Association between electrocardiographic abnormalities and flood exposure among middle-aged and elderly people: A national longitudinal study in China.

BACKGROUND: Flooding has become more frequent and intensive due to climate change, particularly in Asian countries. However, evidence on the long-term health effects of floods from large-scale studies on the vulnerable aged population in China is insufficient. This study analyzed the long-term effects of exposure to flood on electrocardiographic (ECG) abnormalities, a commonly used indicator of cardiovascular disease (CVD) screening, in middle-aged and elderly people. METHOD: We evaluated the Chinese National Stroke Screening Survey data of 80,711 follow-up records from 38,375 participants aged > 40 years with two or more visits between 2013 and 2018 in this longitudinal study. Flood exposure was assessed as the presence of a satellite-detected flooded area within 500 m of the residence within 5 years before the survey date. The association between ECG abnormalities and flood exposure was analyzed using a random effects model with multiple adjustments. As age is an important CVD risk factor, a varying-coefficient function was derived to estimate the nonlinear modifying effect of age on the association between ECG abnormalities and flood exposure. The strata-specific associations between ECG abnormalities and flood exposure were applied to characterize vulnerability to flood. RESULTS: The fully adjusted model suggested that flood exposure was associated with an increased risk for ECG abnormalities among the middle-aged and elderly population (odds ratio [OR] 1.74, 95 % confidence interval [CI] 1.49, 2.03). The ORs of flood exposure for ECG suggesting atrial fibrillation, ST depression, and left ventricular hypertrophy were 1.85 (95 % CI 1.16, 2.94), 6.92 (95 % CI 5.23, 9.16), and 1.55 (95 % CI 0.66, 3.65), respectively. These associations were generally robust in various subpopulations, while a sublinear curve for the negative modifying effect of age was observed on the population vulnerability to flood. CONCLUSION: Flood exposure was associated with an increased long-term risk for an ECG abnormality. The need for effective measures to mitigate vulnerability to flood is not negligible in China.

The Association Between Urbanization and Electrocardiogram Abnormalities in China: a Nationwide Longitudinal Study.

The health effects of urbanization are controversial. The association between urbanization and reversible subclinical risks of cardiovascular diseases (e.g., electrocardiogram (ECG) abnormalities) has rarely been studied. This study aimed to assess the association between urbanization and ECG abnormalities in China based on the China National Stroke Screening Survey (CNSSS). We used changes in the satellite-measured impervious surfaces rate and nighttime light data to assess the level of urbanization. Every interquartile increment in the impervious surfaces rate or nighttime light was related to a decreased risk of ECG abnormalities, with odds ratios of 0.894 (95% CI, 0.869-0.920) or 0.809 (95% CI, 0.772-0.847), respectively. And we observed a U-shaped nonlinear exposure-response relationship curve between the impervious surfaces rate and ECG abnormalities. In conclusion, the current average level of urbanization among the studied Chinese adults remains a beneficial factor for reducing cardiovascular risks.

Dose-response association between physical activity and blood pressure among Chinese adults: a nationwide cross-sectional study.

OBJECTIVES: The aim of this study was to examine the dose-response associations of physical activity with blood pressure (BP) and hypertension risk among Chinese adults. METHODS: Derived from the national community-based China Hypertension Survey database during 2012--2015, a total of 203 108 residents aged at least 18 years were included. Individual-level physical activity was evaluated using a standardized questionnaire, and minutes of metabolic equivalent tasks per week (MET-min/week) were calculated, integrating domain, intensity, frequency, and duration. Multivariable linear and logistic regressions were used to estimate associations of physical activity with BP and hypertension risk, and restricted cubic spline regressions were performed for their nonlinear dose-response relationships. RESULTS: Overall, the median total physical activity (TPA) was 3213.0 MET-min/week and the prevalence of physical inactivity was 14.8%. TPA was negatively associated with BP. Increasing TPA levels was related to a steep decrease in systolic BP, up to approximately 2500 MET-min/week, with more modest benefits above that level of TPA. Higher levels of domain-specific and intensity-specific physical activity were found to be associated with lower BP levels and hypertension risk, except for the association between vigorous-intensity physical activity and systolic BP. We found that TPA within the range of 2000--4000 MET-min/week, a higher frequency and shorter duration were inversely associated with diastolic BP levels. CONCLUSION: Total, domain-specific, and intensity-specific physical activity were inversely related to BP levels, respectively, in a dose-response fashion. Of a given amount, higher-frequency, shorter-duration, and lower-intensity physical activity produced more beneficial effects.

Ambient temperature anomalies induce electrocardiogram abnormalities: Findings from a nationwide longitudinal study.

Electrocardiogram (ECG) outcomes serve as early manifestations of cardiovascular functional or structural changes. While temperature fluctuation has been demonstrated to be a risk factor for cardiovascular diseases, few epidemiological studies have reported its relationship with ECG outcomes. In this study, we employed temperature anomaly (TA) as an innovative indicator of temperature fluctuation to quantify its detrimental impacts on ECG outcomes. A longitudinal study design was conducted using the repeated ECG records of the China National Stroke Screening Survey from 2013 to 2019. Only individuals undergoing at least two ECG tests were included. The daily temperature was assimilated by combining three kinds of data: in situ observations, satellite remote sensing measurements and weather research forecast simulations. We used generalized estimating equations to control for autocorrelation among repeated records and to estimate the association between TA and the risk of ECG abnormalities. We found 6837 events of ECG abnormalities in 47,286 individuals with 102,030 visits. Each unit increment of TA increased the risk of ECG abnormalities [odds ratio (OR) = 1.009, 95% confidence interval (CI): 1.001-1.017] and the risk of myocardial ischemia (OR = 1.061, 95% CI: 1.012-1.111). Hierarchic analyses presented a similar association of TA with both ECG abnormalities (OR = 1.017, 95% CI: 1.008-1.026) and myocardial ischemia (OR = 1.061, 95%CI: 1.011-1.114) in Northern China, but not in Southern China. The exposure-response relationship was estimated as a U-shaped curve centered at the TA value of zero. Sudden warming tended to increase the risk of ECG abnormalities and myocardial ischemia, and sudden cooling tended to increase the risk of atrial fibrillation. All these detrimental effects of TA could be modified by specific individual characteristics. In summary, ambient temperature fluctuation increased the risk of ECG abnormalities. This result indicated that regular ECG tests could be an early-warning measure for monitoring the adverse health effects of temperature fluctuations.

Middle-term nitrogen dioxide exposure and electrocardiogram abnormalities: A nationwide longitudinal study.

BACKGROUND: Recently, professionals, such as those from the World Health Organization, have recommended a rigorous standard for nitrogen dioxide (NO2), a typical urban air pollutant affected by regular traffic emissions, based on its short-term and long-term cardiorespiratory effects. However, the association between middle-term NO2 exposure and cardiovascular disorders remains unknown. OBJECTIVES: This study was conducted to examine the relationship between NO2 exposure and its middle-term cardiovascular risks indicated by electrocardiogram (ECG) abnormalities. METHOD: We included 61,094 subjects (132,249 visits) with repeated ECG observations based on longitudinal data from the China National Stroke Screening Survey (CNSSS). The NO2 exposure concentration was derived from a predictive model, measured as the monthly average concentration in the 6 months of preceding the ECG measurement. We used the generalized estimation equation to assess the association between NO2 exposure and ECG abnormalities. RESULT: For each 10 µg/m3 increase in monthly average NO2 concentration, the odds ratio of ECG abnormalities was 1.10 (95% confidence interval [CI] 1.09-1.12) after multiple adjustments. Stratified regression analyses of urban and rural residents showed associations between middle-term NO2 exposure and ECG abnormalities in urban (OR 1.09 [95% CI 1.08-1.11]) and rural residents (OR 1.14 [95% CI 1.10-1.19]). The association was robust within different subpopulations. Associations generally remained statistically significant (OR 1.03 [95% CI 1.02-1.05]) after extra adjustment for PM2.5. Exposure-response relationship analysis revealed a nearly linear relationship between NO2 exposure and the risk for ECG abnormalities. CONCLUSION: Using the variation in ECG signals as a potentially reversible indicator for subclinical risk in cardiovascular systems, our study provides additional evidence on the increased risk posed by middle-term NO2 exposure. Our study showed that policies controlling for NO2 concentrations are beneficial to prevent cardiovascular diseases among Chinese adults.

Long-term exposure to the components of fine particulate matters and disability after stroke: Findings from the China National Stroke Screening Surveys.

BACKGROUND: Long-term exposure to ambient fine particulate matter (PM2.5) has been linked to an increased risk of stroke. However, the effect of long-term exposure to PM2.5 and its major components on the functional disability of stroke patients remains unclear. METHODS: Based on China National Stroke Screening Survey data obtained from 2013 to 2019, we conducted a national multicenter longitudinal study of the associations of long-term exposure to PM2.5 and its components with the risk of disability after stroke in China. Post-stroke disability was assessed using the modified Rankin scale (mRS), which ranges from 0 to 5, with higher scores indicating greater disability. Long-term exposure to PM2.5 and its five components [sulfate (SO42-), nitrate (NO3-), ammonium salt (NH4+), organic matter (OM), and black carbon (BC)] was determined based on average concentrations during the 3 years preceding mRS administration according to the geographic coordinates of residential communities, using state-of-the-art estimates from multiple sources. We used a fixed-effect model to evaluate the associations between mRS scores and PM2.5 exposure, with adjustment for multiple covariates. RESULTS: Every 10 µg/m3 increase in PM2.5 was associated with a 0.019 (95% confidence interval, 0.003, 0.036) increase in mRS score, but the effect was not significant after adjusting for all covariates [0.016 (95% CI, -0.003, 0.032)]. For PM2.5 components, each IQR (7.92 µg/m3) increment in OM exposure was associated significantly with 0.062 (95% CI, 0.013, 0.111) increment in the mRS score. A significant association was observed between SO42- exposure and the mRS score [0.057 (95% CI, 0.003, 0.112), per IQR: 6.28 µg/m3]. However, no significant association was found with BC, NO3-, or NH4+ exposure. Furthermore, the nonlinear curves were observed for the exposure-response relationship between PM2.5 exposure and the mRS score. CONCLUSION: Greater PM2.5 exposure increased the mRS score and was associated with post-stroke functional disability among stroke patients. However, different chemical components showed unequal neurotoxic effects, and long-term exposure to OM and SO42- may play a more important role. SYNOPSIS: This study reports fine particulate matter at higher concentrations damages the functional ability among specific stroke patients, and PM2.5 components have different neurotoxicities.

Short-term exposure to ozone and ECG abnormalities in China: A nationwide longitudinal study.

Ambient ozone (O3) pollution has been associated with an increased risk of cardiovascular diseases. However, few studies have addressed the effect of O3 exposure on electrocardiogram (ECG) abnormalities, a subclinical indicator of early damage to the cardiovascular system. This study aimed to examine the association between short-term exposure to O3 and ECG abnormalities. We included 102,027 visits of 47,290 participants over 40 years old who had a normal ECG at baseline and then visited again at least once from the China National Stroke Screening Survey (CNSSS). Short-term ozone exposure concentrations were measured as averages of maximum daily 8-h O3 concentrations over the two weeks prior to ECG measurements. The generalized estimation equations models were used to evaluate the association between O3 exposure and ECG abnormalities. For every 10 µg/m3 increment in short-term O3 concentration, the odds ratio of any ECG abnormality was 1.055 (95% confidence interval [CI] 1.045-1.064). For ECG-diagnosed cardiac arrhythmia, the odds ratio was 1.062 (95% CI 1.052-1.072). A nonlinear analysis showed a sublinear relationship between O3 exposure and risk for ECG abnormalities. The association between O3 exposure and ECG abnormalities varied by subpopulation. Our study provided new epidemiological evidence on the association between short-term O3 exposure and ECG abnormalities. There is an urgent need to control ambient O3 pollution to prevent cardiovascular events.

Association between long-term exposure to PM2.5 constituents and electrocardiographic abnormality: A nationwide longitudinal study in China.

BACKGROUND: Electrocardiogram (ECG) abnormalities are known to have prognostic value for heart conditions, while evidence on the relationship between long-term exposure to PM2.5 constituents and electrocardiographic (ECG) abnormalities is limited. This study aimed to quantify the association between long-term exposure to PM2.5 constituents and changes in ECG diagnoses. METHODS: We designed a longitudinal study among participants with repeated records of ECG examination based on the China National Stroke Screening Survey 2013-2018. Logistic regressions with multiple adjustment, estimated by the generalized estimating equation to incorporate repeated measurements, were used to assess the associations between the occurrence of any physician-diagnosed ECG abnormalities and long-term exposure to PM2.5 constituents. RESULTS: We included 61,094 participants with 132,249 visits. All five constituents (sulfate, nitrate, ammonium, organic matter, and black carbon) were significantly associated with an increased risk of ECG abnormalities. The excess risk of ECG abnormalities per interquartile-range increase in exposure was the highest for sulfate (26%, 95% confidence interval [CI] 23-29%), followed by ammonium (22%, 19-26%), nitrate (21%, 17-24%), black carbon (16%, 13-10%) and organic matter (9%,6%-11%). We also found that atrial fibrillation patients might be susceptible to the adverse effects of PM2.5 constituents on ECG. CONCLUSION: Differential associations between various constituents of PM2.5 and ECG abnormalities were found. The unequal toxicities for different chemical constituents of ambient particles on cardiovascular electrophysiological endpoints should be taken into consideration when considering the biological pathways linking PM2.5 and cardiovascular conditions.

Air pollution attenuated the benefits of physical activity on blood pressure: Evidence from a nationwide cross-sectional study.

INTRODUCTION: Although physical activity (PA) has multiple health benefits, the inhaled dose of fine particulate matter (PM2.5) during PA may increase. The trade-off between harmful effects of PM2.5 exposure and protective effects of PA remain unclear. Our study aims to examine the joint effects of PA and PM2.5 exposure on blood pressure (BP) in Chinese adults. METHODS: A total of 203,108 adults aged ≥ 18 years from the China Hypertension Survey study (2012-2015) were included. Individual-level PA was assessed as minutes of metabolic equivalent tasks per week (MET-min/week). The average weekly PM2.5 exposures were estimated by using a spatial resolution of 10 km, integrating multiple data sources, including monitoring values, satellite measurements and model simulations. BP was measured with a professional portable BP monitor. Generalized linear regressions were used to estimate joint associations and to further explore two-dimensional nonlinear associations. RESULTS: The median PA and 4-week PM2.5 average exposures were 3213.0 MET-min/week and 47.8 µg/m3, respectively. PA was negatively associated with BP, while PM2.5 exposure was positively with BP. The associations between PA and systolic BP were significantly modified by PM2.5 exposure (Pinteraction < 0.001). Compared with inactive participants under low PM2.5 exposure, those with highest level of PA under low PM2.5 exposure had a 0.90 (95 % CI: 0.53, 1.26) mmHg decrease in systolic BP, whereas they had a 0.48 (95 % CI: 0.07, 0.89) mmHg increase under high PM2.5 exposure. When PM2.5 exposure was approximately > 25 µg/m3, the joint exposure to total PA and PM2.5 was associated with an increase in systolic BP. CONCLUSIONS: The benefits of PA on BP were counteracted by high PM2.5 levels.

Stillbirths attributable to open fires and their geographic disparities in non-Western countries.

Due to global warming, an increased number of open fires is becoming a major contributor to PM2.5 pollution and thus a threat to public health. However, the burden of stillbirths attributable to fire-sourced PM2.5 is unknown. In low- and middle-income countries (LMICs), there is a co-occurrence of high baseline stillbirth rates and frequent firestorms, which may lead to a geographic disparity. Across 54 LMICs, we conducted a self-matched case-control study, making stillbirths comparable to the corresponding livebirths in terms of time-invariant characteristics (e.g., genetics) and duration of gestational exposure. We established a joint-exposure-response function (JERF) by simultaneously associating stillbirth with fire- and non-fire-sourced PM2.5 concentrations, which were estimated by fusing multi-source data, such as chemical transport model simulations and satellite observations. During 2000-2014, 35,590 pregnancies were selected from multiple Demographic and Health Surveys. In each mother, a case of stillbirth was compared to her livebirth(s) based on gestational exposure to fire-sourced PM2.5. We further applied the JERF to assess stillbirths attributable to fire-sourced PM2.5 in 136 non-Western countries. The disparity was evaluated using the Gini index. The risk of stillbirth increased by 17.4% (95% confidence interval [CI]: 1.6-35.7%) per 10 µg/m3 increase in fire-sourced PM2.5. In 2014, referring to a minimum-risk exposure level of 10 µg/m3, total and fire-sourced PM2.5 contributed to 922,860 (95% CI: 578,451-1,183,720) and 49,951 (95% CI: 3,634-92,629) stillbirths, of which 10% were clustered within the 6.4% and 0.6% highest-exposure pregnancies, respectively. The Gini index of stillbirths attributable to fire-sourced PM2.5 was 0.65, much higher than for total PM2.5 (0.28). Protecting pregnant women against PM2.5 exposure during wildfires is critical to avoid stillbirths, as the burden of fire-associated stillbirths leads to a geographic disparity in maternal health.

[Characteristics and Differences of Household Fine Particulate Matter Pollution Caused by Fuel Burning in Urban and Rural Areas in China].

Objective To explore the overall level,distribution characteristics,and differences in household fine particulate matter (PM2.5) pollution caused by fuel burning in urban and rural areas in China. Methods The relevant articles published from 1991 to 2021 were retrieved and included in this study.The data including the average concentration of household PM2.5 and urban and rural areas were extracted,and the stoves and fuel types were reclassified.The average concentration of PM2.5 in different areas was calculated and analyzed by nonparametric test. Results The average household PM2.5 concentration in China was (178.81±249.91) µg/m3.The mean household PM2.5 concentration was higher in rural areas than in urban areas[(206.08±279.40) µg/m3 vs. (110.63±131.16) µg/m3;Z=-5.45,P<0.001] and higher in northern areas than in southern areas[(224.27±301.66) µg/m3 vs.(130.11±140.61) µg/m3;Z=-2.38,P=0.017].The north-south difference in household PM2.5 concentration was more significant in rural areas than in urban areas[(324.19±367.94) µg/m3 vs.(141.20±151.05) µg/m3,χ2=-5.06,P<0.001].The PM2.5 pollution level showed differences between urban and rural households using different fuel types (χ2=92.85,P<0.001),stove types (χ2=74.42,P<0.001),and whether they were heating (Z=-4.43,P<0.001).Specifically,rural households mainly used solid fuels (manure,charcoal,coal) and traditional or improved stoves,while urban households mainly used clean fuels (gas) and clean stoves.The PM2.5 concentrations in heated households were higher than those in non-heated households in both rural and urban areas (Z=-4.43,P<0.001). Conclusions The household PM2.5 pollution caused by fuel combustion in China remains a high level.The PM2.5 concentration shows a significant difference between urban and rural households,and the PM2.5 pollution is more serious in rural households.The difference in the household PM2.5 concentration between urban and rural areas is more significant in northern China.PM2.5 pollution in the households using solid fuel,traditional stoves,and heating is serious,and thus targeted measures should be taken to control PM2.5 pollution in these households.

Landscape fire smoke enhances the association between fine particulate matter exposure and acute respiratory infection among children under 5 years of age: Findings of a case-crossover study for 48 low- and middle-income countries.

BACKGROUND: Fine particulate matter (PM2.5) produced by landscape fires is thought to be more toxic than that from non-fire sources. However, the effects of "fire-sourced" PM2.5 on acute respiratory infection (ARI) are unknown. METHODS: We combined Demographic and Health Survey (DHS) data from 48 countries with gridded global estimates of PM2.5 concentrations from 2003 to 2014. The proportions of fire-sourced PM2.5 were assessed by a chemical transport model using a variety of PM2.5 source data. We tested for associations between ARI and short-term exposure to fire- and "non-fire-sourced" PM2.5 using a bidirectional case-crossover analysis. The robustness and homogeneity of the associations were examined by sensitivity analyses. We also established a nonlinear exposure-response relationship between fire- and non-fire-sourced PM2.5 and ARI using a two-dimensional spline function. RESULTS: The study included 36,432 children under 5 years who reported ARI symptoms. Each 1 µg/m3 increment of fire-sourced PM2.5 was associated with a 3.2 % (95 % confidence interval [CI] 0.2, 6.2) increment in the risk of ARI. This effect was comparable to that of each ∼5 µg/m3 increment in PM2.5 from non-fire sources (3.1 %; 95 % CI 2.4, 3.7). The association between ARI and total PM2.5 concentration was significantly mediated by the proportion of fire-sourced particles. Nonlinear analysis showed that the risk of ARI was increased by both fire- and non-fire-sourced PM2.5, but especially by the former. CONCLUSIONS: PM2.5 produced by landscape fire was more strongly associated to ARI among children under 5 years than that from non-fire sources.

Short-term effect of PM2.5 on stroke in susceptible populations: A case-crossover study.

BACKGROUND: Fine particulate matter (PM2.5) is a risk factor for stroke, and patients with pre-existing diseases appear to be particularly susceptible. We conducted a case-crossover study to examine the association between short-term exposure to fine particulate matter (PM2.5) and hospital admission for stroke in individuals with atrial fibrillation (AF), hypertension, diabetes, or hyperlipidemia. METHODS: Patients diagnosed with acute ischemic stroke (AIS) were recruited from 2015 to 2017 in Chinese Stroke Center Alliances. We estimated daily PM2.5 average exposures with a spatial resolution of 0.1° using a data assimilation approach combining satellite measurements, air model simulations, and monitoring values. Conditional logistic regression was used to assess PM2.5-related stroke risk in patients with pre-existing medical co-morbidities. RESULTS: A total of 155,616 patients diagnosed with AIS were admitted. Patients with a history of AF (n = 15,430), hypertension (n = 138,220), diabetes (n = 43,737), or hyperlipidemia (n = 16,855) were assessed separately. A 10 µg/m3 increase in daily PM2.5 was associated with a significant increase in AIS for individuals with AF at lag 4 (odds ratio (OR), 1.008; 95% confidence interval (CI), 1.002-1.014), and with hypertension (OR, 1.008; 95% CI, 1.006-1.010), diabetes (OR, 1.006; 95% CI, 1.003-1.010), and hyperlipidemia (OR, 1.007; 95% CI, 1.001-1.012) at lags 0-7. Elderly (⩾ 65 years old) and female patients with AF had significantly higher associations at lag 5 (OR, 1.009; 95% CI, 1.002-1.015) and lag 5 (OR, 1.010; 95% CI, 1.002-1.018), respectively. CONCLUSION: Short-term exposure to PM2.5 is significantly associated with hospital admission for stroke in individuals with pre-existing medical histories, especially in older or female patients with AF. Preventive measures to reduce PM2.5 concentrations are particularly important in individuals with other medical co-morbidities.

Estimation of stillbirths attributable to ambient fine particles in 137 countries.

Gestational exposure to ambient fine particles (PM2.5) increases the risk of stillbirth, but the related disease burden is unknown, particularly in low- and middle-income countries (LMICs). We combine state-of-the-art estimates on stillbirths, and multiple exposure-response functions obtained from previous meta-analyses or derived by a self-matched case-control study in 54 LMICs. 13,870 stillbirths and 32,449 livebirths are extracted from 113 geocoded surveys from the Demographic and Health Surveys. Each stillbirth is compared to livebirth(s) of the same mother using a conditional logit regression. We find that 10-µg/m3 increase of PM2.5 is associated with an 11.0% (95% confidence interval [CI] 6.4, 15.7) increase in the risk of stillbirth, and the association is significantly enhanced by maternal age. Based on age-specific nonlinear PM2.5-stillbirth curves, we evaluate the PM2.5-related stillbirths in 137 countries. In 2015, of 2.09 (95% CI: 1.98, 2.20) million stillbirths, 0.83 (0.54, 1.08) million or 39.7% (26.1, 50.8) are attributable to PM2.5 exposure exceeding the reference level of 10 µg/m3. In LMICs, preventing pregnant women from being exposed to PM2.5 can improve maternal health.

Greenspace exposure and poststroke disability: A nationwide longitudinal study.

INTRODUCTION: Exposure to greenspace has been reported to reduce stroke mortality, but there is a lack of evidence regarding poststroke disability. This study aimed to investigate the association between long-term greenspace exposure and the risk of poststroke disability. METHODS: Based on the China National Stroke Screening Survey from 2013 to 2019, a total of 65,892 visits from 28,085 stroke survivors with ≥ 2 visits were included in this longitudinal study. Long-term greenspace exposure was assessed by a 3-year average of the Normalized Difference Vegetation Index (NDVI) and the proportion of green land cover according to participants' residential communities. Poststroke functional status was assessed with the modified Ranking Score (mRS) at each visit; a cutoff score > 2 indicated disability. Fixed effects regressions were used to examine the association of greenspace exposure with continuous mRS scores or binary indicators for disability. RESULTS: The annual mean NDVI value was 0.369 (standard deviation = 0.120) for all visits among stroke survivors. With full adjustments, each 0.05 increase in NDVI was associated with a 0.056-unit (95 % confidence interval (CI): 0.034, 0.079) decrease in the mRS score and a 46.6 % (95 % CI: 10.0 %, 68.3 %) lower risk of poststroke disability. An L-shaped curve was observed for the nonlinear associations between NDVI and mRS score or disability. Additionally, each 1 % increase in grasslands, savannas, forest, and croplands was associated with 0.008- (95 % CI: 0.002, 0.014), 0.003- (95 % CI: 0.001, 0.005), 0.001- (95 % CI: -0.015, 0.018), and 0.002-unit (95 % CI: -0.003, 0.007) decreases in the mRS score, respectively. CONCLUSIONS: Increasing greenspace was inversely associated with mRS score. Greenspace planning can be a potential intervention to prevent poststroke disability.

Long-Term Exposure to Ozone Increases Neurological Disability after Stroke: Findings from a Nationwide Longitudinal Study in China.

Exposure to ozone (O3) is associated with stroke incidence and mortality. However, whether long-term exposure to O3 is associated with post-stroke neurological disability remains unknown. This study investigated the relationship based on the longitudinal analysis of China National Stroke Screening Survey (CNSSS), which included 65,778 records of stroke patients. All of the analyzed patients were followed-up at least twice. Stroke disability was assessed using the modified Rankin scale (mRS). Long-term exposure was assessed by the peak-season or annual mean of maximum 8-h O3 concentrations for 365 days before the mRS measurement. We used fixed-effect models to evaluate the associations between O3 and mRS score, with adjustment for multiple confounders, and found a 10 µg/m3 increase in peak-season O3 concentration was associated with a 0.0186 (95% confidence interval [CI] 0.0115-0.0256) increment in the mRS score. The association was robust in various subpopulations. For secondary outcomes, for each 10 µg/m3 increment in peak-season O3, the odds ratio of an increased mRS score (vs. unchanged or decreased mRS score) increased by 23% (95% CI 9-37%). A nonlinear analysis showed a sublinear association between O3 exposure and risk for post-stroke disability. A saturation effect was observed at an O3 concentration of more than ~120 µg/m3. Our study adds to evidence that long-term exposure to O3 increases the risk of neurological disability after stroke.

Associations of pregnancy complications with ambient air pollution in China.

BACKGROUND: Gestational hypertension (GH), preeclampsia (PE), and gestational diabetes mellitus (GDM) are common pregnancy complications and can result in maternal and prenatal morbidity and mortality. Air pollution exposure could adversely impact pregnancy complications; however, evidence remains limited in China, where ambient air pollution is relatively severe. OBJECTIVE: This study aims to examine the associations of GH, PE, and GDM with exposure to six air pollutants (PM2.5, PM10, SO2, NO2, O3, and CO) during pregnancy. METHODS: Leveraging a multicenter birth cohort study among pregnant women in 24 hospitals from 15 provinces in China, we obtained data for maternal characteristics and pregnancy outcomes. We generated ambient concentrations of the six air pollutants using a combination of chemical transport model simulations with monitoring data. We used multivariable logistic regression models to estimate the effects on pregnancy complications from exposure to six air pollutants in each trimester and the entire pregnancy. RESULTS: Among the total 3754 pregnant women in this study, the prevalences of GH, GDM, and PE were 2.6 %, 11.2 %, and 0.7 %, respectively. GH risk increased 11.9 % (95 % CI, -8.5 %, 36.8 %) and 13.8 % (1.4 %, 27.8 %) per 10 µg/m3 increases in PM2.5 and PM10 in the entire pregnancy, respectively. PM2.5 and PM10 exposures in the first trimester were significantly associated with an increased risk of GDM. Exposure to O3, SO2, NO2, and CO in early pregnancy could be associated with GDM risk. Geographic region and season of conception may influence the associations of GH and PE with air pollution. CONCLUSIONS: Ambient particulate matter pollution adversely affects GH, GDM, and PE among Chinese pregnant women. Since most regions of China still suffer from hazardous levels of air pollution, our findings indicate importance of better protecting pregnant women from the risk of air pollution.

Medication Adherence and Perceived Social Support of Hypertensive Patients in China: A Community-Based Survey Study.

Purpose: Previous studies suggested perceived social support has impact on medication adherence among hypertensive patients, but did not simultaneously elucidate the different contents or key providers of social support that patients perceived. This study was to identify the contents and providers of perceived social support beneficial for improving medication adherence among hypertensive patients in China, which could prove important for targeted interventions. Patients and Methods: Following a multi-stage stratified sampling framework, a total of 903 hypertensive patients from 12 primary health institutions across a middle-income city were recruited from April to June 2021. Medication adherence was measured using the Chinese version of the Morisky, Green and Levine scale; perceived social support was determined using the name generator method. A binary logistic regression model was performed to identify the association between medication adherence and perceived social support. The contents of support included informational, emotional, and instrumental support (finances and caregiving). The support providers included spouse/partner, children, parents, siblings, other relatives, and friends. Results: A total of 506 (56.04%) patients optimally adhered to their antihypertensive medication. Female, older, urban patients, patients with shorter duration of hypertension and antihypertensive medications used showed better adherence (P<0.05). Optimal medication adherence was positively associated with the overall score of caregiving support (adjusted odds ratio [AOR] = 1.128; 95% confidence interval [CI] = [1.013-1.257]), informational support from the spouse/partner (AOR = 1.574; 95% CI = [1.112-2.227]), emotional support from the spouse/partner (AOR = 1.430; 95% CI = [1.032-1.981]), financial support from the spouse/partner (AOR = 1.439; 95% CI = [1.069-1.937]) and caregiving support from the spouse/partner (AOR = 1.652; 95% CI = [1.130-2.414]), whereas optimal medication adherence was negatively associated with caregiving support from friends (AOR = 0.499; 95% CI = [0.286-0.872]). Conclusion: Informational, emotional, financial and caregiving support from spouses/partners have positive impacts on optimal medication adherence of hypertensive patients of community-level. Community-based interventions designed to improve medication adherence of hypertensive patients should target both patients and their spouses/partners; spouses/partners could be encouraged to provide various support to improve the medication adherence of hypertensive patients.