Ambient air pollution exposure and risk of chronic kidney disease: A systematic review of the literature and meta-analysis.

Ambient air pollution has been identified as one of the leading causes of global burden of disease. The relationship between ambient air pollution exposure and risk of chronic kidney disease (CKD) has stimulated increasing scientific interest in the past few years. However, evidence from human epidemiological studies is still limited and inconsistent. We performed an updated systematic review and meta-analysis to clarify the potential association comprehensively. Selected electronic databases were searched for related English language studies until March 1, 2020 with a final follow-up in December 31, 2020. Risk of bias assessment for individual studies were assessed using the OHAT (Office of Health Assessment and Translation) risk-of-bias rating tool. Confidence rating and level-of-evidence conclusions were developed for bodies of evidence for a given ambient air pollutant. Summary effect estimates were calculated using random-effects meta-analyses when three or more studies are identified for the same air pollutant-CKD combination. A total of 13 studies were finally identified in our study. The meta-analytic estimates (ORs) for risk of CKD were 1.15 (95% CI: 1.07, 1.24) for each 10 µg/m3 increase in PM2.5, 1.25 (95% CI: 1.11, 1.40) for each 10 µg/m3 increase in PM10, 1.10 (95% CI: 1.03, 1.17) for each 10 ppb increase in NO2, 1.06 (95% CI: 0.98, 1.15) for each 1 ppb increase in SO2 and 1.04 (95% CI: 1.00, 1.08) for each 0.1 ppm increase in CO, respectively. The level of evidence was appraised as moderate for four of the five tested air pollutant-CKD combinations using an adaptation of the GRADE (Grading of Recommendations Assessment, Development and Evaluation) tool. In conclusion, this study suggests that certain ambient air pollutant exposure was significantly associated with an increased risk of CKD. Given the limitations, the results of this study should be interpreted with caution, and further well-designed epidemiological studies are needed to draw a definite evidence of a causal relationship.

Ambient concentrations of NO2 and hospital admissions for schizophrenia.

OBJECTIVES: Schizophrenia is a chronic and severe mental disorder affecting more than 21 million people worldwide. Short-term exposure to nitrogen dioxide (NO2) has been associated with hospital admissions (HAs) for mental disorders, but no study has evaluated the specific association of NO2 and schizophrenia. Additionally, the shape of the concentration-response (C-R) curve has not yet been assessed at present. This study aims to investigate the relationship between short-term exposure to NO2 and HAs for schizophrenia in Hefei, from 2014 to 2016. We also attempt to explore the C-R and the underlying effect modifiers of the association. METHODS: Daily number of HAs for schizophrenia was derived from the computerised medical record system of Anhui Mental Health Center. We used a time-series Poisson generalised linear regression combined with distributed lag non-linear models to model the NO2-schizophrenia relationship. RESULTS: A total of 11 373 HAs were identified during the study period. An increase in levels of NO2 was significantly associated with elevated schizophrenia HAs. The estimated relative risk per IQR increase in NO2 at lag 01 was 1.10 (95% CI 1.01 to 1.18). Greater association was observed in young patients (relative risk: 1.11, 95% CI 1.02 to 1.19). The modelled C-R curves of the NO2-schizophrenia relationship suggested possible threshold effects of NO2 for all ages combined, young patients, men and both seasons. CONCLUSIONS: Short-term exposure to NO2 may be associated with increased schizophrenia HAs. Findings indicated potential threshold effects of NO2, which has important implications for health-based risk assessments.

The short-term association between air pollution and childhood asthma hospital admissions in urban areas of Hefei City in China: A time-series study.

BACKGROUND: The impacts of air pollution on asthma attacks have become a hotspot. Previous studies mainly focused on the developed countries or cities. There have been very limited studies in less-developed region to quantify the effects of air pollutants on asthma admissions in children. This study aims to assess the short-term impact of air pollutants on asthma hospital admissions for children in Hefei, China. METHODS: Poisson generalized linear regression combined with distributed lag non-linear model (DLNM) were applied to investigate the effects of air pollutants on daily childhood hospital admissions of asthma from 2015 to 2016, controlling for meteorological factors. Subgroup analyses by sex and age were performed. RESULTS: There were a total of 17,227 asthma admissions during 2015-2016. We found positive correlations between childhood asthma hospital visits and concentrations of NO2, O3, PM10 and PM2.5. Significantly, NO2 exhibited robust positive correlations with cumulative effects 1.551 (95% CI: 1.306-1.841, lag0-3 days) in single-pollutant model and 1.580 (95% CI: 1.315-1.899, lag0-3 days) in multiple-pollutant model. CONCLUSIONS: Air pollutants had adverse effects on childhood asthma. NO2 presented the greatest effect, followed by PM2.5. Results will be important for health authority and guardians to realize the severity of air pollution on the increased risk of asthma, so as to develop relevant strategies and health interventions to meet the challenges of childhood asthma and reduce air pollution.

Risk effects of high and low relative humidity on allergic rhinitis: Time series study.

BACKGROUND: The relationship between environmental factors and allergic rhinitis (AR) has become a focal point recently. However, few studies have investigated the adverse effects of both high relative humidity (RH) and low relative humidity. Moreover, the laged effect and disease burden of RH on AR were also neglected. OBJECTIVES: To explore the association of both high and low RH on daily AR hospital outpatients, and to quantify the corresponding disease burden attributable to RH. METHODS: In our study, we define 95th as high RH and 5th as low RH. A distributed lag non-linear model (DLNM) combined with a Poisson generalized linear regression model were applied to analyze the relationship between RH and hospital outpatients for AR. All patients were retrieved from Anhui Provincial Children's Hospital (n = 37,221) from January 2015 to December 2016. Daily meteorological and air pollutant data were collected by Hefei Meteorological Bureau and Environmental Protection Agency. Subgroup analyses were conducted by gender and occupational groups. RESULTS: Acute adverse effects of high and low RH on AR were explored respectively, with an increase of daily AR outpatients when encountered high and low RH. The low RH presented a risk effect at current day and lasted up to the eighth day. However, high RH began to appear a risk effect on the fourth day. Notably, the fraction of hospital outpatients attributable to low RH was 5.22% (95% CI: 1.92%, 8.33%) and high RH was 4.07% (95% CI: 1.13%, 7.30%) in the backward perspective. Additionally, male and students apparent to be more sensitive to the effects of low RH. CONCLUSION: This study suggests that both high and low RH are potential trigger for AR hospital outpatients in Hefei, China. Our studies might offer valuable messages to health practitioners and useful direction to decisions-makers respectively.

Impact of short-term temperature variability on emergency hospital admissions for schizophrenia stratified by season of birth.

Diurnal temperature range (DTR) and temperature change between neighboring days (TCN) are important meteorological indicators closely associated with global climate change. However, up to date, there have been no studies addressing the impacts of both DTR and TCN on emergency hospital admissions for schizophrenia. We conducted a time-series analysis to assess the relationship between temperature variability and daily schizophrenia onset in Hefei, an inland city in southeast China. Daily meteorological data and emergency hospital admissions for schizophrenia from 2005 to 2014 in Hefei were collected. After stratifying by season of birth, Poisson generalized linear regression combined with distributed lag nonlinear model (DLNM) was used to examine the relationship between temperature variability and schizophrenia, adjusting for long-term trend and seasonality, mean temperature, and relative humidity. Our analysis revealed that extreme temperature variability may increase the risk for schizophrenia onset among patients born in spring, while no such association was found in patients born in summer and autumn. In patients born in spring, the relative risks of extremely high DTR comparing the 95th and 99th percentiles with the reference (50th, 10 °C) at 3-day lag were 1.078 (95 % confidence interval (CI) 1.025-1.135) and 1.159 (95 % CI 1.050-1.279), respectively. For TCN effects, only comparing 99th percentile with reference (50th, 0.7 °C) was significantly associated with emergency hospital admissions for schizophrenia (relative risk (RR) 1.111, 95 % CI 1.002-1.231). This study suggested that exposure to extreme temperature variability in short-term may trigger later days of schizophrenia onset for patients born in spring, which may have important implications for developing intervention strategies to prevent large temperature variability exposure.

Impact of weather factors on hand, foot and mouth disease, and its role in short-term incidence trend forecast in Huainan City, Anhui Province.

Hand, foot, and mouth disease (HFMD) is one of the most common communicable diseases in China, and current climate change had been recognized as a significant contributor. Nevertheless, no reliable models have been put forward to predict the dynamics of HFMD cases based on short-term weather variations. The present study aimed to examine the association between weather factors and HFMD, and to explore the accuracy of seasonal auto-regressive integrated moving average (SARIMA) model with local weather conditions in forecasting HFMD. Weather and HFMD data from 2009 to 2014 in Huainan, China, were used. Poisson regression model combined with a distributed lag non-linear model (DLNM) was applied to examine the relationship between weather factors and HFMD. The forecasting model for HFMD was performed by using the SARIMA model. The results showed that temperature rise was significantly associated with an elevated risk of HFMD. Yet, no correlations between relative humidity, barometric pressure and rainfall, and HFMD were observed. SARIMA models with temperature variable fitted HFMD data better than the model without it (sR 2 increased, while the BIC decreased), and the SARIMA (0, 1, 1)(0, 1, 0)52 offered the best fit for HFMD data. In addition, compared with females and nursery children, males and scattered children may be more suitable for using SARIMA model to predict the number of HFMD cases and it has high precision. In conclusion, high temperature could increase the risk of contracting HFMD. SARIMA model with temperature variable can effectively improve its forecast accuracy, which can provide valuable information for the policy makers and public health to construct a best-fitting model and optimize HFMD prevention.

The association between greenery type and gut microbiome in schizophrenia: did all greenspaces play the equivalent role?

In recent years, attention has been focused on the benefit of greenspace on mental health, and it is suggested this link may vary with the type of greenspace. More and more studies have emphasized the influence of the gut microbiome on schizophrenia (SCZ). However, the effects of greenspaces on the gut microbiota in SCZ and the effect of different types of greenspaces on the gut microbiota remain unclear. We aim to examine if there were variations in the effects of various greenspace types on the gut microbiome in SCZ. Besides, we sink to explore important taxonomic compositions associated with different greenspace types. We recruited 243 objects with schizophrenia from Anhui Mental Health Center and collected fecal samples for 16Sr RNA gene sequencing. Three types of greenery coverage were calculated with different circular buffers (800, 1500, and 3000 m) corresponding to individual addresses. The association between greenspace and microbiome composition was analyzed with permutational analysis of variance (PERMANOVA). We conducted the linear regression to capture specific gut microbiome taxa associated with greenery coverage. Tree coverage was consistently associated with microbial composition in both 1500 m (R2 = 0.007, P = 0.030) and 3000 m (R2 = 0.007, P = 0.039). In contrast, there was no association with grass cover in any of the buffer zones. In the regression analysis, higher tree coverage was significantly correlated with the relative abundance of several taxa. Among them, tree coverage was positively associated with increased Bifidobacterium longum (ß = 1.069, P = 0.004), which was the dominant composition in the gut microbiota. The relationship between greenspace and gut microbiome in SCZ differed by the type of greenspace. Besides, "tree coverage" may present a dominant effect on the important taxonomic composition. Our findings might provide instructive evidence for the design of urban greenspace to optimize health and well-being in SCZ as well as the whole people.

Ambient temperature, sunlight duration, and suicide: A systematic review and meta-analysis.

BACKGROUND: The relationship between sunlight hours, temperature, and suicide has been investigated in many previous studies, but with inconsistent findings. We conducted this meta-analysis aiming at providing clear evidence about whether sunlight hours and temperature can affect the risk of suicide. METHODS: Relevant literature published before 7 Jul 2018 was searched in three electronic database of PubMed, Web of science and Cochrane. Between-study heterogeneity in the effect estimates were examined by study design (i.e., exposure time resolution, temperature measure and suicide classification) and population vulnerability (i.e., sex, national income level, climate zone and study location). RESULTS: Regarding temperature-suicide association, we identified 14 studies that provided 23 effect estimates for meta-analysis. Our random-effects model showed that each 1 °C increase in temperature was significantly associated with a 1% increase in the incidence of suicide (Incidence Rate Radio (IRR) = 1.01; 95%CI = 1.00-1.02; p < 0.05). As for sunlight duration and suicide, 11 effect estimates from 4 studies were pooled using a fixed-effects model. Significant association between sunlight duration (per 1 h increase) and the risk of suicide was not observed, and the pooled IRR was 1.00 (95%CI = 0.99-1.01; p > 0.05). There was significant heterogeneity between previous studies' effect estimates, and significantly lower heterogeneity was noted for the female group, for studies that did analyses at daily scale, and for studies using mean temperature as the exposure indicator. CONCLUSION: Our findings suggest a significant and positive association between temperature rises and incidence of suicide, and a non-significant association between sunlight duration and incidence of suicide. Populations living in tropical and temperate zones or at middle-income level may be particularly vulnerable to temperature increase.

Trimester-specific association between antibiotics exposure during pregnancy and childhood asthma or wheeze: the role of confounding.

PURPOSE: We conducted the meta-analysis to respectively evaluate the risk of prenatal antibiotics use during specific trimesters (first, second, and third trimester) on childhood asthma or wheeze and to explore whether the association was biased by potential confounding. METHODS: The quality of included articles was assessed according to Newcastle-Ottawa Quality Assessment Scale and the Strengthening the Reporting of Observational Studies in Epidemiology. A random effects model was used to calculate pooled risk ratios and corresponding 95% confidence interval (CI), and publication bias was tested by Egger statistical test. RESULTS: Eight studies were included finally. We found a crude positive association of prenatal antibiotics use during each pregnancy trimester and risk of childhood asthma or wheeze with RRs of 1.28 (95% CI, 1.09-1.51) for the first trimester of pregnancy, 1.25 (95% CI, 1.02-1.52) for the second trimester, and 1.25 (95% CI, 1.05-1.49) for the third trimester. However, when considering potential factors of maternal infections and presence of siblings, the relationship for each trimester was insignificant. CONCLUSIONS: This systemic review and meta-analysis proposed a crude positive association between prenatal antibiotic use in every specific trimester and risk of childhood asthma or wheeze. However, adjustment for confounders decreased the relative risk estimates, supporting the concept that these associations are, at least in part, because of confounding by indication.

Exposure to traffic-related air pollution and acute bronchitis in children: season and age as modifiers.

BACKGROUND: Acute bronchitis (AB) is one of the principal causes of childhood morbidity. Increasing number of studies has shown that air pollution is an important environmental contributor of respiratory disease. However, evidence so far is scarce regarding the effects of air pollution on childhood AB, and it also remains unclear how the risk of AB will change by season and age. METHODS: Data on hospital visits for AB in children, air pollution and meteorological factors from 1 January 2015 to 31 December 2016 were collected in Hefei, China. Time-series analysis was applied to assess the short-term effects of traffic-related air pollution on childhood AB outpatient visits. A Poisson generalised linear regression model combined with a distributed lag non-linear model was used to estimate the relationships, controlling for long-term trends, seasonal patterns, meteorological factors and other possible confounders. RESULTS: We found that an IQR increase in concentrations of nitrogen dioxide, particulate matter <2.5 µm and carbon monoxide significantly increased the daily hospital visits for childhood AB with 4-day cumulative effect estimates (relative risks: 1.03, 95% CI 1.01 to 1.05; 1.09, 95% CI 1.07 to 1.11; 1.07, 95% CI 1.05 to 1.09). Notably, the risk estimates during the cold season are pronounced; however, no significant association was observed during the warm season. Interestingly, children aged 6-14 years were more vulnerable to air pollutants than children aged less than 1 year and within 1-5 years. However, no gender difference was observed. CONCLUSION: A significant association of traffic-related air pollution and increased department visits for childhood AB was observed, notably in school-age children and during the cold season.

Ambient temperature, humidity and hand, foot, and mouth disease: A systematic review and meta-analysis.

BACKGROUND: The relationship between ambient temperature, humidity and hand, foot, and mouth disease (HFMD) has been highlighted in East and Southeast Asia, which showed multiple different results. Therefore, our goal is to conduct a meta-analysis to further clarify this relationship and to quantify the size of these effects as well as the susceptible populations. METHODS: PubMed, Web of science, and Cochrane library were searched up to November 22, 2017 for articles analyzing the relationships between ambient temperature, humidity and incidence of HFMD. We assessed sources of heterogeneity by study design (temperature measure and exposed time resolution), population vulnerability (national income level and regional climate) and evaluated pooled effect estimates for the subgroups identified in the heterogeneity analysis. RESULTS: We identified 11 studies with 19 estimates of the relationship between ambient temperature, humidity and incidence of HFMD. It was found that per 1°C increase in the temperature and per 1% increase in the relative humidity were both significantly associated with increased incidence of HFMD (temperature: IRR, 1.05; 95% CI, 1.02-1.08; relative humidity: IRR, 1.01; 95% CI, 1.00-1.02). Subgroup analysis showed that people living in subtropical and middle income areas had a higher risk of incidence of HFMD. CONCLUSIONS: Ambient temperature and humidity may increase the incidence of HFMD in Asia-Pacific regions. Further studies are needed to clarify the relationship between ambient temperature, humidity and incidence of HFMD in various settings with distinct climate, socioeconomic, and demographic features.

Is the serious ambient air pollution associated with increased admissions for schizophrenia?

BACKGROUND: Much of the research has shown an increased risk of psychiatric disorders in association with elevated exposure to air pollution, such as NO2, PM10 and SO2. However, few studies investigate the effect of these air pollution on the risk of schizophrenia admissions and the lagged effect among different subgroups. METHODS: A distributed lag non-linear model (DLNM) combined with a Poisson generalized linear regression model was applied to analyzing the relationship between schizophrenia and air pollution. At first, according to the minimum AIC criterion, we discussed the lagged effect of NO2, PM10 and SO2 for 5 days, 4 days and 10 days, respectively. Then, we chose benchmarks as references (25th) to conduct comparisons with different levels of pollutant concentrations (90th and 95th). All patients were retrieved from the Psychiatric Hospital of TongLing (n = 3469) from January 2014 to December 2016. Daily air pollutants and meteorological data were collected from the Chinese national air quality monitoring (NAQM) and Meteorological Bureau. Subgroup analysis was conducted by gender (male and female), age (0-19 ages, 20-39 ages, 40-59 ages and ≥ 60 ages) and occupation (farmer, worker and unemployed). RESULTS: The effects of the three air pollutants were statistically significant to schizophrenia admissions. We found that NO2 and PM10 have short-term effects of 4 days and 3 days (NO2: lag 0-4 RR, 1.84(95% CI: 1.49-2.27), PM10: lag 0-3 RR, 1.97(95%CI: 1.57-2.36)), respectively. SO2 had longer effects for 10 days (SO2: lag 0-10 RR, 2.93(95%CI: 2.10-4.10)). Additionally, it significantly increased the risk of schizophrenia episode in subjects with male, 20-59 ages, farmer and worker. CONCLUSION: We find adverse effects of ambient air pollutants on schizophrenia admissions in TongLing, China, which may provide valuable information for the policy makers and local health authorities to conduct effective intervention of air pollution on schizophrenia.

The burden of extreme heat and heatwave on emergency ambulance dispatches: A time-series study in Huainan, China.

BACKGROUND: Although studies have well documented increased mortality risk during extreme heat and heatwaves, few have examined their impacts on emergency ambulance dispatches under different temperature metrics. Additionally, evidence on the attributable risk of emergency ambulance dispatches due to extreme heat and heatwaves is scarce around the world. METHODS: A distributed lag nonlinear model (DLNM) was applied to quantify the impact of extreme heat and heatwaves on emergency ambulance dispatches in Huainan, China, during 2011-2013. Several local extreme heat and heatwave definitions were tested by using percentile of daily mean temperature (i.e., 95th, 97.5th and 99th) and duration (i.e.,≥2 consecutive days and ≥3 consecutive days). The fraction of emergency ambulance dispatches attributable to extreme heat and heatwaves was also quantitatively estimated. RESULTS: Both extreme heat and heatwaves were significantly associated with increases in emergency ambulance dispatches, and their effects appeared to be acute. For extreme heat effects, the relative risks (RRs) of emergency ambulance dispatches at lag0 steadily increased from 95th percentile of daily mean temperature (1.03, 95% confidence interval (CI): 1.01-1.05) to 99th percentile (1.07, 95% CI: 1.05-1.10). For heatwave effects, we observed that RRs of emergency ambulance dispatches at lag0 fluctuated between 1.03 and 1.05 across different heatwave definitions. Notably, the fraction of emergency ambulance dispatches attributable to extreme heat decreased with higher percentile of daily mean temperature, dropping from 2.24% (95% CI: 1.41%-2.99%) at 95th percentile to 0.69% (95% CI: 0.45%-0.92%) at 99th percentile. Likewise, we found that heatwaves with higher intensity and (or) longer duration accounted for lower fraction of emergency ambulance dispatches, varying between 0.51%-1.52%. CONCLUSIONS: Our findings may have important implications for the development of local heat warming systems and public health interventions to lessen the impact of extreme heat events on population health.

Is greater temperature change within a day associated with increased emergency admissions for schizophrenia?

BACKGROUND: Diurnal temperature range (DTR), as an important index of climate change, has been increasingly used to evaluate the impacts of temperature variability on human health. However, little is known about the effects of DTR on schizophrenia. OBJECTIVE: The present study aims to examine the relationship between DTR and schizophrenia admissions, and further, to explore whether the association varied by individual characteristics and study periods. METHODS: A Poisson generalized linear regression combined with distributed lag non-linear model (DLNM) was applied to analyze daily DTR and schizophrenia data from Hefei, China during 2005 to 2014, after adjusting for long-term and seasonal trends, mean temperature, relative humidity and other confounding factors. RESULTS: An acute adverse effect of extremely high DTR on schizophrenia was observed, with a 2.7% (95% CI: 1.007-1.047) increase of daily schizophrenia admissions after exposure to extremely high DTR (95th percentile vs. 50th percentile). The risk for schizophrenia onset due to large DTR exposure increased from the first five years (2005-2009) to the second five years (2010-2014). Additionally, the patient aged 15-29 and 50-64years, male patients, patients born in spring/autumn, and married patients appeared to be more vulnerable to DTR effect. However, there was no significant association between moderately high DTR (75th percentile) and schizophrenia. CONCLUSIONS: This study suggests that extremely high DTR is a potential trigger for schizophrenia admissions in Hefei, China. Our findings may provide valuable information to decisions-makers and guidance to health practitioners.

Exposure to bisphenol A and the development of asthma: A systematic review of cohort studies.

BACKGROUND: There is conflicting evidence about the association between bisphenol A (BPA) exposure and childhood asthma risk. We aimed to review the epidemiological literature on the relationship between prenatal or postnatal exposure to BPA and the risk of childhood asthma/wheeze. METHODS: The PubMed database was systematically searched, and additional studies were found by searching reference lists of relevant articles. RESULTS: Six studies fulfilled the eligibility criteria. Three studies found that prenatal BPA exposure is associated with an increased risk of childhood wheeze, while another study reported a reduced risk of wheeze. Regarding the postnatal BPA exposure, three studies demonstrated an increased risk of childhood asthma/wheeze. CONCLUSIONS: The mean prenatal BPA was associated with the risk of childhood wheeze/asthma. Besides, the influence of BPA exposure during the second trimester of pregnancy on the prevalence of childhood wheeze was marked. Further studies are urgently needed to explore the underlying mechanism about adverse effect of BPA exposure on childhood wheeze/asthma.