Surrounding greenness is associated with lower risk and burden of low birth weight in Iran.

The nexus between prenatal greenspace exposure and low birth weight (LBW) remains largely unstudied in low- and middle-income countries (LMICs). We investigated a nationwide retrospective cohort of 4,021,741 live births (263,728 LBW births) across 31 provinces in Iran during 2013-2018. Greenness exposure during pregnancy was assessed using satellite-based normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). We estimated greenness-LBW associations using multiple logistic models, and quantified avoidable LBW cases under scenarios of improved greenspace through counterfactual analyses. Association analyses provide consistent evidence for approximately L-shaped exposure-response functions, linking 7.0-11.5% declines in the odds of LBW to each 0.1-unit rise in NDVI/EVI with multiple buffers. Assuming causality, 3931-5099 LBW births can be avoided by achieving greenness targets of mean NDVI/EVI, amounting to 4.4-5.6% of total LBW births in 2015. Our findings suggest potential health benefits of improved greenspace in lowering LBW risk and burden in LMICs.

Short-term effects of fine particulate matter constituents on myocardial infarction death.

Existing evidence suggested that short-term exposure to fine particulate matter (PM2.5) may increase the risk of death from myocardial infarction (MI), while PM2.5 constituents responsible for this association has not been determined. We collected 12,927 MI deaths from 32 counties in southern China during 2011-2013. County-level exposures of ambient PM2.5 and its 5 constituents (i.e., elemental carbon (EC), organic carbon (OC), sulfate (SO42-), ammonium (NH4+), and nitrate (NO3-)) were aggregated from gridded datasets predicted by Community Multiscale Air Quality Modeling System. We employed a space-time-stratified case-crossover design and conditional logistic regression models to quantify the association of MI mortality with short-term exposure to PM2.5 and its constituents across various lag days. Over the study period, the daily mean PM2.5 mass concentration was 77.8 (standard deviation (SD) = 72.7) µg/m3. We estimated an odds ratio of 1.038 (95% confidence interval (CI): 1.003-1.074), 1.038 (1.013-1.063) and 1.057 (1.023-1.097) for MI mortality associated with per interquartile range (IQR) increase in the 3-day moving-average exposure to PM2.5 (IQR = 76.3 µg/m3), EC (4.1 µg/m3) and OC (9.1 µg/m3), respectively. We did not identify significant association between MI death and exposure to water-soluble ions (SO42-, NH4+ and NO3-). Likelihood ratio tests supported no evident violations of linear assumptions for constituents-MI associations. Subgroup analyses showed stronger associations between MI death and EC/OC exposure in the elderly, males and cold months. Short-term exposure to PM2.5 constituents, particularly those carbonaceous aerosols, was associated with increased risks of MI mortality.

Ambient PM2.5, ozone and mortality in Chinese older adults: A nationwide cohort analysis (2005-2018).

BACKGROUND: Cohort evidence linking long-term survival with exposure to multiple air pollutants (e.g., fine particulate matter [PM2.5] and ozone) was extensively sparse in low- and middle-income countries, especially among older adults. This study aimed to investigate potential associations of long-term exposures to PM2.5 and ozone with all-cause mortality in Chinese older adults. METHODS: A dynamic nationwide prospective cohort comprising 20,352 adults aged ≥65 years were enrolled from the Chinese Longitudinal Healthy Longevity Study and followed up through 2005-2018. Participants' annual exposures to warm-season ozone and year-round PM2.5 were assigned using satellite-derived spatiotemporal estimates. A directed acyclic graph (DAG) was developed to identify confounding variables. Associations of annual mean exposures to PM2.5 and ozone with mortality were evaluated using single- and two-pollutant Cox proportional hazards models, adjusting for time-dependent individual risk factors and ambient temperature. RESULTS: During 100 thousand person-years of follow-up (median: 3.6 years), a total of 14,313 death events occurred. The participants were averagely aged 87.1 years at baseline and exposed to a wide range of annual average concentrations of warm-season maximum 8-hour ozone (mean, 54.4 ppb; range, 23.3-81.6 ppb) and year-round PM2.5 (mean, 65.5 µg/m3; range, 10.1-162.9 µg/m3). Approximately linear concentration-response relationship was identified for ozone, whereas significant increases in PM2.5-associated mortality risks were observed only when concentrations were above 60 µg/m3. Rises of 10 ppb in ozone and 10 µg/m3 in PM2.5 above 60 µg/m3 were associated with increases in all-cause mortality of 13.2% (95% confidence interval [CI]: 10.2-16.2%) and 6.2% (95% CI: 4.6-7.7%) in DAG-based single-pollutant model, and of 9.7% (95% CI: 6.6-13.0%) and 5.3% (95% CI: 3.7-6.9%) in DAG-based two-pollutant model, respectively. We detected significant effect modification by temperature in associations of mortality with ozone (P <0.001 for interaction), suggesting greater ozone-related risks among participants in warmer locations. CONCLUSIONS: This study provided longitudinal evidence that long-term exposure to ambient PM2.5 and ozone significantly and independently contributed to elevated risks of all-cause mortality among older adults in China.

Submicron particle exposure and stroke hospitalization: An individual-level case-crossover study in Guangzhou, China, 2014-2018.

BACKGROUND: Short-term exposure to ambient PM2.5 and PM10 (particulate matter with aerodynamic diameters ≤2.5 µm and 10 µm, respectively) has been linked with hospitalization and mortality from stroke. However, the effect of PM1 (≤1 µm) exposure on the risk of hospitalization from stroke and its subtypes has rarely been investigated, in particular, on the basis of fine-scale exposure assessment at the individual level. METHODS: We collected data on hospital admissions due to stroke and its subtypes in Guangzhou, China from January 1, 2014 to December 31, 2018. Daily exposures to PM1, PM2.5, and PM10 were assessed from satellite-derived estimates at a 1-km2 spatial resolution based on residential addresses. A time-stratified case-crossover analysis combined with a conditional logistic regression model was performed to examine the associations of stroke hospitalization risks with short-term exposure to size-fractional particles. We conducted stratified analyses by sex, age, season, and ambient temperature. RESULTS: A total of 178,586 stroke hospitalizations were recorded during the study period, among which 141,709 cases were ischemic stroke and 25,255 cases were hemorrhagic stroke. The mean concentrations on the day of hospitalization were 20.0 µg/m3 (control days: 19.9 µg/m3) for PM1, 37.6 µg/m3 (37.4 µg/m3) for PM2.5, and 59.3 µg/m3 (59.0 µg/m3) for PM10. Short-term exposure to size-fractional particles was significantly associated with increased risks of hospital admission for overall stroke and ischemic stroke, whereas null or negative associations were observed for hemorrhagic stroke. Compared with PM2.5 and PM10, PM1 was associated with greater excess risks of stroke hospitalizations. For each 10-µg/m3 increase in PM1, PM2.5, and PM10 exposure at lag 03-day, the odds ratios were 1.016 (95% confidence interval: 1.008, 1.024), 1.007 (1.003, 1.011), and 1.007 (1.004, 1.010) for overall stroke hospitalization, and were 1.023 (1.014, 1.033), 1.010 (1.005, 1.014), and 1.009 (1.006, 1.013) for ischemic stroke, respectively. These associations were robust to co-pollutant adjustments and did not vary by sex and age, while significantly elevated risks were identified in cold months (October to March of the next year) and low-temperature days (<23.8 °C) only. CONCLUSIONS: Short-term exposure to particulate matter air pollution, particularly PM1, was associated with increased risks of hospitalization for overall stroke and ischemic stroke.

Short-term exposure to fine particulate matter constituents and mortality: case-crossover evidence from 32 counties in China.

A growing number of studies associated increased mortality with exposures to specific fine particulate (PM2.5) constituents, while great heterogeneity exists between locations. In China, evidence linking PM2.5 constituents and mortality was extensively sparse. This study primarily aimed to quantify short-term associations between PM2.5 constituents and non-accidental mortality among the Chinese population. We collected daily mortality records from 32 counties in China between January 1, 2011, and December 31, 2013. Daily concentrations of main PM2.5 constituents (organic carbon (OC), elemental carbon (EC), nitrate (NO3-), sulfate (SO42-), and ammonium (NH4+)) were estimated using the modified Community Multiscale Air Quality model. Time-stratified case-crossover design with conditional logistic regression models was adopted to estimate mortality risks associated with short-term exposures to PM2.5 mass and its constituents. Stratification analyses were done by sex, age, and season. A total of 116,959 non-accidental deaths were investigated. PM2.5 concentrations on the day of death were averaged at 75.7 µg m-3 (control day: 75.6 µg m-3), with an interquartile range (IQR) of 65.2 µg m-3. Per IQR rise in PM2.5, EC, OC, NO3-, SO42-, and NH4+ at lag-04 day was associated with an increase in non-accidental mortality of 2.4% (95% confidence interval, (1.0-3.7), 1.7% (0.8-2.7), 2.9% (1.6-4.3), 2.1% (0.4-3.9), 1.0% (0.2-1.9), and 1.6% (0.3-2.9), respectively. Both PM2.5 mass and its constituents were strongly associated with elevated cardiovascular mortality risks, but only PM2.5, EC, and OC were positively associated with respiratory mortality at lag-3 day. PM2.5 mass and its constituents associated effects on mortality varied among sex- and age-specific subpopulations. Differences in the seasonal pattern of associations exist among PM2.5 constituents, with stronger effects related to EC and NO3- in warm months but SO42- and NH4+ in cold months. Short-term exposures to PM2.5 compositions were positively associated with increased risks of mortality, particularly those constituents from combustion-related sources.

Early-life exposure to PM2.5 constituents and childhood asthma and wheezing: Findings from China, Children, Homes, Health study.

BACKGROUND: Emerging evidence suggests that early-life (in-utero and first-year since birth) exposure to ambient PM2.5 is a risk factor for asthma onset and exacerbation among children, while the hazards caused by PM2.5 compositions remain largely unknown. OBJECTIVE: To examine potential associations of early-life exposures to PM2.5 mass and its major chemical constituents with childhood asthma and wheezing. METHODS: By conducting the Phase II of the China, Children, Homes, Health study, we investigated 30,325 preschool children aged 3-6 years during 2019-2020 in mainland China. Early-life exposure to PM2.5 mass and its constituents (i.e., black carbon [BC], organic matter [OM], nitrate, ammonium, sulfate) were calculated based on monthly estimates at a 1 km × 1 km resolution from satellite-based models. We adopted a novel quantile-based g-computation approach to assess the effect of a mixture of PM2.5 constituents on childhood asthma/wheezing. RESULTS: The average PM2.5 concentrations during in-utero and the first year since birth were 64.7 ± 10.6 and 61.8 ± 10.5 µg/m3, respectively. Early-life exposures to a mixture of major PM2.5 constituents were significantly associated with increased risks of asthma and wheezing, while no evident compositions-wheezing associations were found in the first year. Each quintile increases in all five PM2.5 components exposures in utero was accordingly associated with an odds ratio of 1.18 [95% confidence interval: 1.07-1.29] for asthma and 1.08 [1.01-1.16] for wheezing. BC, OM and SO42- contributed more to risks of asthma and wheezing than the other PM2.5 constituents during early life, wherein the effects of BC were only observed during pregnancy. Sex subgroup analyses suggested stronger associations among girls of first-year exposures to PM2.5 components with childhood asthma. CONCLUSION: Early-life exposures to ambient PM2.5, particularly compositions of BC, OM and SO42-, are associated with an increased risk of childhood asthma.

Secular trends in global burden of diabetes attributable to particulate matter pollution from 1990 to 2019.

Increasing evidence suggests an association between fine particulate matter (PM2.5) exposure and type 2 diabetes mellitus. However, there is still a lack of comparative evaluation regarding diabetes burden due to ambient and indoor PM2.5 pollution at a global scale. This study attempts to provide a systematic and comprehensive profile for PM2.5-attributable burden of diabetes and its spatiotemporal trends, globally and regionally. Comparative estimates of diabetes attributable to ambient PM2.5 and household air pollution (HAP) from solid fuels for 204 countries and territories were derived from the Global Burden of Disease Study 2019. Globally, 292.5 (95% uncertainty interval: 207.1, 373.4) thousand deaths and 13.0 (9.1, 17.2) million disability-adjusted life years (DALYs) from diabetes were attributed to PM2.5 pollution in 2019, wherein more than two-thirds (67.3% deaths and 69.7% DALYs) were contributed by ambient PM2.5. Compared to 1990, age-standardized DALY rate (ASDR) in 2019 attributable to ambient PM2.5 increased by 85.9% (APC: 2.21% [2.15, 2.27]), while HAP-associated ASDR decreased by 37.9% (APC: - 1.66% [- 1.82, - 1.50]). We observed a negative correlation between SDI and APC in ASMR (rs = - 0.5, p < 0.001) and ASDR (rs = -0.4, p < 0.001) among 204 countries and territories. HAP-related diabetes experienced a sharp decline during 1990-2019, while global burden of diabetes attributable to ambient PM2.5 was rising rapidly. The elderly and people in low-SDI countries suffered from the greatest burden of diabetes due to PM2.5 pollution. More targeted interventions should be taken by governments to reduce PM2.5 exposure and related diabetes burden.

Longitudinal association of egg intake frequency with cardiovascular disease in Chinese adults.

BACKGROUND AND AIMS: Reducing dietary cholesterol is generally acceptable for the prevention of cardiovascular disease (CVD). Eggs are nutrient-dense and common food items across the world, while rich in cholesterol. The potential effects of egg intake on cardiovascular health remain uncertainty and have been under debate in past decades. METHODS AND RESULTS: A nationwide cohort of 20,688 participants aged 16-110 years without CVD at baseline were derived from the China Family Panel Studies. Egg consumption was assessed by a semi-quantitative food frequency questionnaire. We adopted stratified Cox proportional hazards model with random intercepts for provinces to evaluate associations of egg intake with CVD incidence. During a median follow-up of 6.0 years, we identified 2395 total CVD incidence and mean egg consumption was 3 times/week. Egg intakes were associated lower risks of CVD incidence in the multivariate-adjusted model. Compared with the non-consumers, the corresponding HRs (95% confidence interval) for total CVD events were 0.84 (0.74-0.94) for 1-2 times per week, 0.78 (0.69-0.88) for 3-6/week, and 0.83 (0.72-0.95) for ≥7/week. Similar relationships were found in hypertension. Approximately non-linear relationships were observed between egg consumption with total CVD and hypertension incidence, identifying the lowest risk in 3-6 times/week. Subgroup analyses estimated lower risks of total CVD and hypertension in females only, with significant effect modification by sex (P for interaction = 0.008 and 0.020). CONCLUSION: Egg consumption may be associated with lower risks of CVD incidence among Chinese adults. Our findings could have implications in CVD prevention and might be considered in the development of dietary guidelines.

Reduction in daily ambient PM2.5 pollution and potential life gain by attaining WHO air quality guidelines in Tehran.

BACKGROUND: Fine particulate matter pollution (PM2.5) is widely considered to be a top-ranked risk factor for premature mortality and years of life lost (YLL). However, evidence regarding the effect of daily air quality improvement on life expectancy is scarce, especially in the Middle East such as Iran. This study aimed to investigate the potential benefits in life expectancy at concentrations meeting the daily PM2.5 standards during 2012-2016 in Tehran, Iran. METHODS: We collected daily non-accidental mortality and data on air pollutants and weather conditions from Tehran, Iran, 2012-2016. A quasi-Poisson or Gaussian time-series regression was employed to fit the associations between ambient PM2.5 and mortality or YLL. Potential gains in life expectancy (PGLE) and attributable fraction (AF) were estimated by assuming that daily PM2.5 concentrations attained the World Health Organization air quality guidelines (WHO AQG) 2005 (25 µg/m3) and 2021 (15 µg/m3). RESULTS: During the study period, a total of 221,231 non-accidental deaths were recorded in Tehran, resulting in 3.6 million YLL. The mean concentration of ambient PM2.5 was 34.7 µg/m3 (standard deviation: 15.3 µg/m3). For a 10-µg/m3 rise in 4-day moving average (lag 03-day) in PM2.5 concentration, non-accidental mortality and YLL increased by 1.12% (95% confidence interval: 0.60, 1.65) and 20.73 (7.08, 34.39) person years, respectively. A relatively higher effect was observed in males and young adults aged 18-64 years. We estimated that 39830 [AF = 1.1%] and 74284 [AF = 2.1%] YLL could potentially be avoided if daily PM2.5 concentrations attained the WHO AQG 2005 and 2021, respectively, which corresponded to potential gains in life expectancy of 0.18 (0.06, 0.30) and 0.34 (0.11, 0.56) years for each deceased person. PM2.5-associated PGLE estimates were largely robust when performing sensitivity analyses. CONCLUSIONS: Our findings indicated that short-term exposure to PM2.5 is associated with increased non-accidental YLL and mortality. Prolonged life expectancy could be achieved if the particulate matter air pollution level were kept under a stricter standard.