Ambient air pollution and asthma onset in Taiwanese adults

Chronic exposure to ambient air pollution and the risk of non-alcoholic fatty liver disease: A cross-sectional study in Taiwan and Hong Kong

BACKGROUND

Information on the relation of air pollution with non-alcoholic fatty liver disease (NAFLD) is scarce. We thus conducted a large cross-sectional study in Asia to investigate the role of air pollution in NAFLD.

METHODS

We recruited 329,048 adults (mean age: 41.0 years) without other liver disease (hepatitis and cirrhosis) or excessive alcohol consumption in Taiwan and Hong Kong from 2001 to 2018. The concentrations of nitrogen dioxide (NO2) and ozone (O3) were estimated using a space-time regression model, and the concentrations of fine particulate matter (PM2.5) was evaluated using a satellite-based spatio-temporal model. NAFLD was determined using either the fatty liver index (FLI) or the hepatic steatosis index (HSI). The NAFLD-related advanced fibrosis was defined according to BARD score or the fibrosis-4 (FIB-4). A logistic regression model was adopted to explore the relationships of ambient air pollution with the odds of NAFLD and NAFLD-related advanced fibrosis.

RESULTS

We found positive relationships between PM2.5 and the odds of NAFLD and advanced fibrosis, with every standard deviation (SD, 7.5 µg/m3) increases in PM2.5 exposure being associated with a 10% (95% confidence interval [CI]: 9%-11%) increment in the prevalence of NAFLD and an 8% (95% CI: 7%-9%) increment in the prevalence of advanced fibrosis. Similarly, the prevalence of NAFLD and advanced fibrosis increased by 8% (95% CI: 7%-9%) and 7% (95% CI: 6%-8%) with per SD (18.9 µg/m3) increasement in NO2 concentration, respectively. Additionally, for every SD (9.9 µg/m3) increasement in O3 concentration, the prevalence of NAFLD and advanced fibrosis decreased by 12% (95% CI: 11%-13%) and 11% (95% CI: 9%-12%), respectively.

CONCLUSION

Higher ambient PM2.5 and NO2 are linked with higher odds of NAFLD and advanced fibrosis. Our findings indicate that reducing PM2.5 and NO2 concentrations may be an effective way for preventing NAFLD. Further studies on O3 are warranted.

The frequency of asthma and its related factors: results of the enrolment phase of Tabari cohort study

INTRODUCTION

A large portion of the world's population has asthma. This study aimed to ascertain asthma prevalence and related factors in the Tabari cohort study (TCS).

METHODS

The TCS included 10,255 35-70-year-olds from urban and mountainous Sari (northern Iran) between June 2015 and November 2017. Education, occupation, domicile, socioeconomic position, history of psychiatric disorders, smoking (including hookah smoking), opium usage, and daily physical activity level were determined.

RESULTS

The final analysis included 9939 individuals. The asthma rate was 7.4%. Multiple factors increased asthma risk, according to statistical analysis. These factors included being female (OR, 1.337; 95% CI, 1.142-1.565), retired (OR, 1.553; 95% CI, 1.205-2.002), living in the city (OR, 1.268; 95% CI, 1.083-1.484), using opioids (OR, 1.689; 95% CI, 1.299-2.197), having lower socioeconomic status (SES) (OR, 0.723; 95% CI, 0.579-0.903), history of psychiatric disorders (OR, 2.313; 95% CI, 1.826-2.930), and aged 60-70 (OR, 2.325; 95% CI, 1.765-3.064), and BMI above 30 kg/m2 (OR, 1.499; 95% CI, 1.220-1.841). Several factors increased asthma probability in multivariate regression analysis. These factors include being female (OR = 1.389, p = 0.015), ages between 60 and 70 (OR = 2.034, p < 0.001), using opioids (OR = 1.940, p < 0.001), lower SES (OR = 0.738, p = 0.012), history of psychiatric disorders (OR = 2.035, p < 0.001), BMI above 30 kg/m2 (OR = 1.518, p < 0.001), and being a smoker (OR = 1.337, p = 0.056).

CONCLUSION

This study has identified that the prevalence of asthma in the Tabari cohort group is high. In addition, it was demonstrated that various factors are related to asthma.

Spatial variance and estimation of nitrogen dioxide levels as a contributing factor to asthma epidemiology in Rawalpindi, Pakistan

Asthma prevalence and morbidity are increasing rapidly worldwide, especially in developing countries. Previous studies have shown nitrogen dioxide as an important contributor to asthma prevalence along with extreme temperatures, relative humidity, and land use change. The present study aimed to assess the asthma epidemiology and association of nitrogen dioxide, temperature, and land use as a contributing factor for increasing asthma prevalence in Rawalpindi, Pakistan. Secondary data related to the frequency of asthmatics hospital visits were analyzed to figure out the hotspots of asthma by using Getis ord Gi* statistics in ArcGIS 10.2. Moreover, intraurban variation of nitrogen dioxide concentration was analyzed by passive sampling method and its association with the rate of asthmatics hospital visits in Rawalpindi, Pakistan was also researched. Results revealed the random distribution of disease with significant hotspots along with spatial variability of nitrogen dioxide in urban and rural locations. Indoor and outdoor levels of nitrogen dioxide exceed the national and world health organization standards on asthma high risk areas especially in winter season. Congested housing with poor ventilation, unplanned urbanization, cold temperature, and unclean fuel use are revealed as strong determinants of asthma prevalence in Rawalpindi, Pakistan. Extensive monitoring and interventions are needed for the reduction of both indoor and outdoor nitrogen dioxide levels to overcome the increasing rate of asthma prevalence.

Association of air pollution, genetic risk, and lifestyle with incident adult-onset asthma: A prospective cohort study

BACKGROUND

Numerous studies have explored the association of air pollution with asthma but have yielded conflicting results. The exact role of air pollution in the incidence of adult-onset asthma and whether this effect is modified by genetic risk, lifestyle, or their interaction remain uncertain.

METHODS

We conducted a prospective cohort study on 298,738 participants (aged 37-73 years) registered in the UK Biobank. Cox proportional hazard models were used to evaluate the association of air pollution, including particulate matter (PM_2.5, PM_coarse, and PM₁₀), nitrogen dioxide (NO₂), and nitrogen oxides (NO_x), with asthma incidence. We constructed genetic risk and lifestyle scores, assessed whether the impact of air pollution on adult-onset asthma risk was modified by genetic susceptibility or lifestyle factors, and evaluated the identified interactions.

RESULTS

We found that each interquartile range increase in annual concentrations of PM_2.5, NO₂, and NO_x was related to 1.04 (95% confidence interval [CI]: 1.01, 1.08), 1.04 (95% CI: 1.00, 1.08), and 1.03 (95% CI: 1.00, 1.06) times the risk of adult-onset asthma, respectively. The size of the effect of air pollution was greater among subpopulations with low genetic risk or unfavorable lifestyles. We also identified an additive interaction effect of air pollution with lifestyle factors, but not with genetic risk, on the risk of adult-onset asthma.

CONCLUSION

Our analyses show that air pollution increases the risk of adult-onset asthma, but that the size of the effect is modified by lifestyle and genetic risk. These findings emphasize the need for integrated interventions for environmental pollution by the government as well as adherence to healthy lifestyles to prevent adult-onset asthma.

Outdoor air pollution and the onset and exacerbation of asthma

Exposure to outdoor air pollution has been consistently associated with asthma. In this study, we reviewed the epidemiological studies published within the last 5 years on the association between outdoor air pollution and exacerbation and onset of asthma. A large number of studies have been published within the last 5 years. Short-term exposure to outdoor air pollution is associated with exacerbation of pre-existing asthma, manifested as worsening of symptoms and increasing of asthma-related emergency room visits and hospital admissions. Furthermore, increasing evidence suggests that long-term exposure to outdoor air pollution can result in onset of asthma. Children are more susceptible to outdoor air pollution. Future studies should be conducted to explore the mechanisms underlying the association between air pollutants and onset of asthma, including gene involvement. In addition, disentangling the effect of a mixture of air pollutants and identifying the key components of air pollution will complete the existing evidence. More importantly, a better understanding is required on the future impact of air pollution on asthma under a changing climate.