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Concerns exist that the positive association of physical activity with better lung function, which has been suggested in previous longitudinal studies in smokers, is due to reverse causation. To investigate this, we applied structural equation modeling (SEM), an exploratory approach, and marginal structural modeling (MSM), an approach from the causal inference framework that corrects for reverse causation and time-dependent confounding and estimates causal effects, on data from participants in the European Community Respiratory Health Survey (ECRHS, a multicentre European cohort study initiated in 1991–1993 with ECRHS I, and with two follow-ups: ECRHS II in 1999–2003, and ECRHS III in 2010–2014). 753 subjects who reported current smoking at ECRHS II, with repeated data on lung function at ECRHS I, II and III, physical activity at ECRHS II and III, and potential confounders at ECRHS I and II, were included in the analyses. SEM showed positive associations between physical activity and lung function in both directions. MSM suggested a protective causal effect of physical activity on lung function (overall difference in mean β (95% CI), comparing active versus non-active individuals: 58 mL (21–95) for forced expiratory volume in one second and 83 mL (36–130) for forced vital capacity). Our results suggest bi-directional causation and support a true protective effect of physical activity on lung function in smokers, after accounting for reverse causation and time-dependent confounding. [ABSTRACT FROM AUTHOR]

[Display omitted] • More residential greenspace was not associated with better lung function. • Increased NDVI was associated with a slightly faster decline in FVC. • Residing near green spaces might be associated with a faster decline in FEV 1 and FVC. The few studies that have examined associations between greenspace and lung function in adulthood have yielded conflicting results and none have examined whether the rate of lung function decline is affected. We explored the association between residential greenspace and change in lung function over 20 years in 5559 adults from 22 centers in 11 countries participating in the population-based, international European Community Respiratory Health Survey. Forced expiratory volume in 1 s (FEV 1) and forced vital capacity (FVC) were measured by spirometry when participants were approximately 35 (1990 – 1994), 44 (1999 – 2003), and 55 (2010 – 2014) years old. Greenness was assessed as the mean Normalized Difference Vegetation Index (NDVI) in 500 m, 300 m, and 100 m circular buffers around the residential addresses at the time of lung function measurement. Green spaces were defined as the presence of agricultural, natural, or urban green spaces in a circular 300 m buffer. Associations of these greenspace parameters with the rate of lung function change were assessed using adjusted linear mixed effects regression models with random intercepts for subjects nested within centers. Sensitivity analyses considered air pollution exposures. A 0.2-increase (average interquartile range) in NDVI in the 500 m buffer was consistently associated with a faster decline in FVC (−1.25 mL/year [95% confidence interval: −2.18 to −0.33]). These associations were especially pronounced in females and those living in areas with low PM 10 levels. We found no consistent associations with FEV 1 and the FEV 1 /FVC ratio. Residing near forests or urban green spaces was associated with a faster decline in FEV 1 , while agricultural land and forests were related to a greater decline in FVC. More residential greenspace was not associated with better lung function in middle-aged European adults. Instead, we observed slight but consistent declines in lung function parameters. The potentially detrimental association requires verification in future studies. [ABSTRACT FROM AUTHOR]

Background: Some but not all previous studies report that pneumonia in children aged less than five years is associated with lower lung function and elevated risk of respiratory disease. To date, none have explored these associations in at-risk populations such as First Nations Australians, whose incidence of early childhood pneumonia is among the highest reported in the world. Methods: This cross-sectional study included 1276 First Nations Australian children/young adults aged 5–25 years recruited from regional/remote Queensland and Northern Territory communities and schools. Associations between pneumonia and both spirometry values and asthma were investigated using linear and logistic regression. Results: Early childhood pneumonia was associated with lower FEV1 and FVC Z-scores, but not FEV1/FVC% Z-scores, when occurring before age three (FEV1 β = −0.42, [95%CI −0.79, −0.04]; FVC β = −0.62, [95%CI −1.14, −0.09]), and between three and five years (β = −0.50, [95%CI −0.88, −0.12]; β = −0.63, [95%CI −1.17, −0.10]), compared to those who never had pneumonia. Similarly, pneumonia occurring when aged before age three years (OR = 3.68, 95%CI 1.96–6.93) and three to five years (OR = 4.81, 95%CI 1.46–15.8) was associated with increased risk of asthma in later childhood. Conclusions: Early childhood pneumonia is associated with lung function deficits and increased asthma risk in later childhood/early adulthood in First Nations Australians. The disproportionate impact of pneumonia on at-risk children must be addressed as a priority. [ABSTRACT FROM AUTHOR]

Ambient air pollution exposure and influenza virus infection have been documented to be independently associated with reduced lung function previously. Influenza vaccination plays an important role in protecting against influenza-induced severe diseases. However, no study to date has focused on whether influenza vaccination may modify the associations between ambient air pollution exposure and lung function. We undertook a cross-sectional study of 6740 children aged 7–14 years into Seven Northeast Cities (SNEC) Study in China during 2012–2013. We collected information from parents/guardians about sociodemographic factors and influenza vaccination status in the past three years. Lung function was measured using portable electronic spirometers. Machine learning methods were used to predict 4-year average ambient air pollutant exposures to nitrogen dioxide (NO 2) and particulate matter with an aerodynamic diameter <1 μm (PM 1), <2.5 μm (PM 2.5) and <10 μm (PM 10). Two-level linear and logistic regression models were used to assess interactions between influenza vaccination and long-term ambient air pollutants exposure on lung function reduction, controlling for potential confounding factors. Ambient air pollution were observed significantly associated with reductions in lung function among children. We found significant interactions between influenza vaccination and air pollutants on lung function, suggesting greater vulnerability to air pollution among unvaccinated children. For example, an interaction (p interaction = 0.002) indicated a −283.44 mL (95% CI: −327.04, −239.83) reduction in forced vital capacity (FVC) per interquartile range (IQR) increase in PM 1 concentrations among unvaccinated children, compared with the −108.24 mL (95%CI: −174.88, −41.60) reduction in FVC observed among vaccinated children. Results from logistic regression models also showed stronger associations between per IQR increase in PM 1 and lung function reduction measured by FVC and peak expiratory flow (PEF) among unvaccinated children than the according ORs among vaccinated children [i.e., Odds Ratio (OR) for PM 1 and impaired FVC: 2.33 (95%CI: 1.79, 3.03) vs 1.65 (95%CI: 1.20, 2.28); OR for PM 2.5 and impaired PEF: 1.45 (95%CI: 1.12,1.87) vs 1.04 (95%CI: 0.76,1.43)]. The heterogeneity of the modification by influenza vaccination of the associations between air pollution exposure and lung function reduction appeared to be more substantial in girls than in boys. Our results suggest that influenza vaccination may moderate the detrimental effects of ambient air pollution on lung function among children. This study provides new insights into the possible co-benefits of strengthening and promoting global influenza vaccination programs among children. Image 1 • No study on interactions between flu vaccine and air pollution on lung function. • Flu vaccine may mitigate the detrimental effects of air pollution on lung function. • The interactions appeared to be more substantial in girls than in boys. [ABSTRACT FROM AUTHOR]

There is a large body of evidence linking Environmental Tobacco Smoke (ETS) exposure with impaired lung function. However, it is not known whether exposure to pets modifies this relationship. To investigate if pet ownership changes the association between ETS exposure and lung function, a population-based sample of 7326 children, 7–14 years old, were randomly recruited from 24 districts in northeast China. Lung function including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV 1), peak expiratory flow (PEF), and maximal mid-expiratory flow (MMEF) was measured by spirometry, while pet ownership time periods and ETS exposure were collected by questionnaire. Two-level regression analysis was done, with covariates controlled for. The results showed pet exposure in certain early lifetime windows modified the associations of ETS exposure on decreased lung function in children. Among children exposed to current ETS, those exposed to pets in utero had greater reductions in lung function (for instance: OR for reduced FVC (<85% predicted) = 10.86; 95% CI: 3.80–30.97) than those not exposed to pets in utero (OR = 2.32; 95% CI: 1.76–3.05) (p interaction = 0.005). While, children exposed to current pet ownership reduced the lung function impairment induced by ETS exposure during the first 2 years of life and/or ETS exposure during pregnancy, especially for FVC impairment. For instance, OR (95%CI) for reduced FVC (<85% predicted) was 0.81 (0.56, 1.18) and 1.42 (1.15, 1.74), respectively, for children with or without current pet ownership exposed to ETS during the first 2 years of life (p interaction = 0.010). Furthermore, pet type or number of pets did not significantly modify associations between ETS exposure and lung function. In conclusion, the timing of pet ownership modified associations between ETS exposure and lung function, pet ownership in utero and during the first 2 years of life significantly worsened the adverse impacts of passive smoking on lung function. • Studies of joint effects of pet ownership and ETS on children's lung function are rare. • We explored this topic in 6740 Chinese children from 49 schools in 7 cites. • Pet exposure in certain early lifetime windows modified the associations of ETS exposure on decreased lung function. • Pet ownership in utero and during the first 2 years of life worsened the adverse impacts of ETS exposure on lung function. [ABSTRACT FROM AUTHOR]