Detrimental effects of air pollution on adult lung function

The Role of Mitochondrial Quality Control in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity, mortality, and health care use worldwide with heterogeneous pathogenesis. Mitochondria, the powerhouses of cells responsible for oxidative phosphorylation and energy production, play essential roles in intracellular material metabolism, natural immunity, and cell death regulation. Therefore, it is crucial to address the urgent need for fine-tuning the regulation of mitochondrial quality to combat COPD effectively. Mitochondrial quality control (MQC) mainly refers to the selective removal of damaged or aging mitochondria and the generation of new mitochondria, which involves mitochondrial biogenesis, mitochondrial dynamics, mitophagy, etc. Mounting evidence suggests that mitochondrial dysfunction is a crucial contributor to the development and progression of COPD. This article mainly reviews the effects of MQC on COPD as well as their specific regulatory mechanisms. Finally, the therapeutic approaches of COPD via MQC are also illustrated.

Subcutaneous emphysema, pneumomediastinum and pneumothorax in COVID-19 pneumonia-independent prognostic factors

The ongoing coronavirus disease 2019 pandemic has created a substantial disease burden and morbidity. However, the development of subcutaneous emphysema, pneumomediastinum, and pneumothorax have been of rare occurrence and their significance in mortality has not been studied. In a retrospective single-institution observational study at a tertiary care centre in the northern part of India, we evaluated the occurrence of these complications and their relationship with mortality from 1 June 2020 to 30 November 2020. All coronavirus disease 2019 (COVID-19) patients developing subcutaneous emphysema, pneumomediastinum, and pneumothorax were included. Cardiopulmonary resuscitation-induced complications were excluded. Measured endpoints were either discharge to home or death. There were 3145 COVID-19 patients admitted during the study period. Altogether, 38 patients developed one of these complications or in combination. There were 33 male and 5 female patients with an age range from 23 to 95 years, mean 57 ± 12.7. 36 of 38 patients developed these complications while on the ventilator and required chest drain insertions as a part of management. Two patients developed these complications while breathing spontaneously. The incidence of these complications among ventilated patients was 22.9% (36/157). 32 of 38 died giving a mortality of 84.21%. The average time from the development of these complications to death was 8.4 days (range 2-27 days). We conclude that lung changes in COVID-19 patients make them prone to the development of air leaks. Subcutaneous emphysema, pneumomediastinum, and pneumothorax were more common in ventilated patients but were also observed in spontaneously breathing patients. These complications were associated with significantly high mortality in COVID-19 patients (p-value = 0.0002 by Chi-square test).

Air pollution and COPD: GOLD 2023 committee report

Exposure to air pollution is a major contributor to the pathogenesis of COPD worldwide. Indeed, most recent estimates suggest that 50% of the total attributable risk of COPD may be related to air pollution. In response, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) Scientific Committee performed a comprehensive review on this topic, qualitatively synthesised the evidence to date and proffered recommendations to mitigate the risk. The review found that both gaseous and particulate components of air pollution are likely contributors to COPD. There are no absolutely safe levels of ambient air pollution and the relationship between air pollution levels and respiratory events is supra-linear. Wildfires and extreme weather events such as heat waves, which are becoming more common owing to climate change, are major threats to COPD patients and acutely increase their risk of morbidity and mortality. Exposure to air pollution also impairs lung growth in children and as such may lead to developmental COPD. GOLD recommends strong public health policies around the world to reduce ambient air pollution and for implementation of public warning systems and advisories, including where possible the use of personalised apps, to alert patients when ambient air pollution levels exceed acceptable minimal thresholds. When household particulate content exceeds acceptable thresholds, patients should consider using air cleaners and filters where feasible. Air pollution is a major health threat to patients living with COPD and actions are urgently required to reduce the morbidity and mortality related to poor air quality around the world.

Identifying the threshold of outdoor PM2.5 reversing the beneficial association between physical activity and lung function: A national longitudinal study in China

BACKGROUND

Despite cumulative evidence reports the interaction effects of physical activity (PA) and air pollution on lung function, the findings have been inconsistent. We aimed to identify the threshold values that reverse the beneficial effects of PA on lung function.

METHODS

This multistage probability sampling study examined 13,032 individuals aged ≥45 years across China from 2011 to 2015. City-level particulate matter 2.5 μm or less in diameter (PM_2.5) were estimated based on a two-stage machine learning model, with a spatial resolution of 0.1° × 0.1°. We assessed PA and a range of covariates using standardized self-reported questionnaires. The peak expiratory flow (PEF) was measured using a peak flow meter. We used mixed-effects linear regression models to examine the associations between PA and PM_2.5, and their interactions with PEF.

RESULTS

Participants were 60.4 ± 9.4 years old [mean ± standard deviation (SD)]. The mean ± SD of PM_2.5 and PEF was 54.4 ± 23.0 μg/m³ and 273 ± 116 L/min, respectively. Each 10 μg/m³ increase in PM_2.5 was associated with a 1.27 L/min decrease in PEF. The PEF increased by 2.48 (95% confidence interval, CI: 0.40, 4.55) L/min, 0.74 (95% CI: -1.17, 2.66) L/min, and 1.99 (95% CI: 0.001, 3.99) L/min following a 10 h/week increment of walking, moderate intensity PA, and vigorous intensity PA, respectively. Detrimental associations between PM_2.5 and PEF outweighed PA benefits for approximate PM_2.5 concentrations >81 μg/m³ (95% CI: 58.9, 111) and >77 μg/m³ (95% CI: 39.7, 102) for walking and vigorous intensity PA, respectively.

CONCLUSIONS

We identified the threshold of ambient PM_2.5 above which the beneficial association of PA with lung function may be reversed to an adverse one. Although the threshold may vary across populations and places, the findings suggested that reducing air pollution could enhance the benefits of PA on lung function.

Do improved biomass cookstove interventions improve indoor air quality and blood pressure? A systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis evaluates the most recent evidence to examine whether use of improved biomass cookstoves in households in low-middle income countries results in reduction in mean concentrations of carbon monoxide (CO) and particulate matter of size 2.5 μm (PM_2.5) in the cooking area, as well as reduction in mean systolic (SBP) and diastolic blood pressure (DBP) of adults using the cookstoves when compared to adults who use traditional three stone fire or traditional biomass cookstoves.

METHODS

We searched databases of scientific and grey literature. We included studies if published between January 2012 and June 2021, reported impact of ICS interventions in non-pregnant adults in low/middle-income countries, and reported post-intervention results along with baseline of traditional cookstoves. Outcomes included 24- or 48-h averages of kitchen area PM_2.5, CO, mean SBP and DBP. Meta-analyses estimated weighted mean differences between baseline and post-intervention values for all outcome measures.

RESULTS

Eleven studies were included; ten contributed estimates for HAP and four for BP. Interventions lead to significant reductions in PM_2.5 (-0.73 mg/m³, 95% CI: -1.33, -0.13), CO (-8.37 ppm, 95%CI: -13.20, -3.54) and SBP (-2.82 mmHg, 95% CI: -5.53, -0.11); and a non-significant reduction in DBP (-0.80 mmHg, 95%CI: -2.33, 0.73), when compared to baseline of traditional cookstoves. Except for DBP, greatest reductions in all outcomes came from standard combustion ICS with a chimney, compared to ICS without a chimney and advanced combustion ICS.

CONCLUSION

Among the reviewed biomass stove types, ICS with a chimney feature resulted in greatest reductions in HAP and BP.

Influences of environmental exposures on preterm lung disease

Introduction: Environmental factors play a critical role in the progression or resolution of chronic respiratory diseases. However, studies are limited on the impact of environmental risk factors on individuals born prematurely with lung disease after they leave the neonatal intensive care unit and are discharged into the home environment.Areas covered: In this review, we cover current knowledge of environmental exposures that impact outcomes of preterm respiratory disease, including air pollution, infections, and disparities. The limited data do suggest that certain exposures should be avoided and there are potential preventative strategies for other exposures. There is a need for additional research outside the neonatal intensive care unit that focuses on individual and community-level factors that affect long-term outcomes.Expert opinion: Preterm respiratory disease can impose a significant burden on infants, children, and young adults born prematurely, but may improve for many individuals over time. In this review, we outline the exposures that may potentially hasten, delay, or prevent resolution of lung injury in preterm children.

Perceptions and knowledge of air pollution and its health effects among caregivers of childhood cancer survivors: a qualitative study

BACKGROUND

Emerging research suggests that survivors of childhood and adolescent cancers are at risk for morbidity and mortality associated with air pollutants. However, caregiver perceptions of the effects of air pollution are unknown. Thus, to address this gap we described caregivers' perceptions of air pollution's impact on general population health and specifically on childhood cancer survivors, and caregivers' air pollution information-seeking and exposure reduction behaviors.

METHODS

Participants were Utah residents, ≥18 years, and caregiver of a childhood cancer survivor who had completed treatment. Semi-structured interviews were conducted with caregivers to describe their perspectives on air quality, how air pollution impacts health (general population and survivor health), and their information seeking and exposure reduction behaviors. Interviews were recorded, transcribed, and analyzed through two rounds of structured coding.

RESULTS

Caregivers (N = 13) were non-Hispanic white and primarily females (92.3%) between 30 and 49 years old (46.2%). Most families lived within the Wasatch Front (69.2%), the main metropolitan of Utah. Two categories emerged pertaining to caregiver's perceptions of air pollution: 1) Limited awareness about the health effects of air pollution, and 2) Unsuccessful information seeking and minimal exposure reduction behaviors. All caregivers held negative perceptions of air pollution in Utah, but most were unaware of how pollution affects health. While some families limited air pollution exposure by avoiding outdoor activity or physically leaving the region, few practiced survivor-specific exposure reduction. Nearly half of caregivers worried about potential effects of air pollution on survivor health and wanted more information.

CONCLUSIONS

Despite negative perceptions of air pollution, caregivers were divided on whether air pollution could impact survivor health. Few caregivers engaged in exposure reduction for their cancer survivor. As air pollution levels increase in the U.S., continued research on this topic is essential to managing cancer survivor respiratory and cardiovascular health.