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Background: Constrained by no proper way to assess cumulative exposure, the joint effect of air pollution cumulative exposure doses on childhood asthma and wheezing (AW) was not understood., Objective: To assess the association between cumulative exposure to multiple air pollutants in early life and childhood AW., Methods: We designed a nested case-control study based on the birth cohort in Jinan City. Children with AW followed up within 2 years after birth were treated as cases, and non-cases in this cohort were treated as the control source population, and the propensity score matching method was used to match each case to 5 controls. We calculated the individual cumulative outdoor exposure doses for each period using an inverse distance weighted model, alongside the complex Simpson's formula, accounting for outdoor time and respiratory volume. The Least absolute shrinkage and selection operator (Lasso) regression was performed to screen for covariates. To analyze the joint effects of pollutants, we employed the weighted quantile sum (WQS) regression model in conjunction with conditional logistic regression., Results: 84 cases and 420 controls were included in this study. The odds ratio (OR) with 95% confidence interval (CI) of the impact of cumulative exposure (mg/m 3 ) after birth on childhood AW was 1.78 (1.15-2.74) for SO 2 , 1.69 (1.11-2.57) for NO 2 , and 1.65 (1.09-2.52) for PM 2.5 , respectively. Furthermore, with each 25th percentile increase in the WQS index, the overall risk of cumulative doses for six pollutants exposure after birth on AW increased by an adjusted OR of 1.10 (1.03, 1.18), and SO 2 , PM 2.5 , and NO 2 contributed the most to the WQS index. However, no statistically significant association was found between cumulative exposure to all pollutants before birth and childhood AW., Conclusions: There was a joint effect of the cumulative exposure dose of outdoor air pollutants after birth on AW in children aged 0-2 years. And traffic-related pollutants (SO 2 , PM 2.5 , and NO 2 ) make a greater contribution to the joint effect., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: To describe the short-term and long-term effects of cesarean section on childhood asthma and wheezing., Method: Firstly, in the cohort study, 6640 infants were included in the cohort baseline from January 2018 to December 2019, in which 6501 children completed the follow-up study for respiratory diseases at age 2 years. The effect of cesarean section on asthma and wheezing was estimated by the logistic regression model. Secondly, we conducted a meta-analysis of studies with outcomes of childhood asthma and wheezing under 2 years of age and over 2 years of age, respectively, to investigate the short-term and long-term effects of cesarean section on asthma and wheezing., Results: In our cohort study, the cumulative incidence of asthma and wheezing was 1.3% (84/6501). 45.5% of children (2961/6501) were born by cesarean section. The adjusted odds ratio for the effect of cesarean section on asthma and wheezing in children under 2 years of age was 1.14 (95%CI 0.73-1.78). Combining previous studies (outcomes of asthma and wheezing under 2 years of age) with our results for a meta-analysis, the odds ratio was 1.15 (95%CI 1.05-1.25, I 2  = 46.82%). Meanwhile, cesarean section had a long-term effect on asthma and wheezing in the child population over 2 years of age (OR = 1.17, 95%CI 1.11-1.24, P < 0.001, I 2  = 79.38%)., Conclusion: Cesarean section had a short-term effect on asthma and wheezing before the age of 2, in addition, the long-term effect of cesarean section on asthma and wheezing persisted in the child population (under 18)., Competing Interests: Declaration of competing interest The authors declared that they have no conflicts of interest to this work., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Given differences in vulnerability of children in early life, a life course approach to asthma and wheezing (AW) in young children caused by ozone (O 3 ) is not fully understood., Methods: We conducted a birth cohort in Jinan, China from 2018 to 2021 to elucidate the onset model of childhood AW due to O 3 exposure. An inverse distance weighted model was used for individual exposure assessment. The time-dependent Cox proportional-hazard model and logistic model were used to investigate the effects of O 3 exposure on AW. Principal component analysis, interaction analysis, and distributed lag model were used to analyze the life course approach., Results: The cumulative incidence rate for AW among 6501 children aged 2 was 1.4%. A high level of O 3 was related to AW (HR: 2.10, 95% CI: 1.31, 3.37). Only O 3 exposure after birth was associated with AW, with an OR of 1.82 (1.08, 3.12), after adjusting for the effect before birth. Furthermore, adjusting for other air pollutants, the HR for the individual effect of high O 3 exposure on AW was 2.44 (1.53, 3.89). Interestingly, P values for interactions for O 3 and the principal components of other pollutants, as well as the characteristic variable of open windows were less than 0.1. Moreover, an increase in the IQR of O 3 exposure at the 31st to 37th weeks before birth and the 1st to 105th weeks after birth was associated with an increase in the HRs for AW., Conclusions: High-level of O 3 exposure after birth could lead to AW among young children. Importantly, the AW onset model may include the risk factors accumulation and the sensitive period model. Specifically, there are two sensitive windows in early life, and the correlated insults between the high level of O 3 and other pollutants as well as open windows in the asthma-inducing effect., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The objective of this study was to explore the impact of maternal AT during pregnancy on childhood asthma and wheezing, as well as the potential effect modifiers in this association. A cross-sectional study was implemented from December 2018 to March 2019 in Jinan to investigate the prevalence of childhood asthma and wheezing among aged 18 months to 3 years. Then, we conducted a case-control study based on population to explore the association between prenatal different AT exposure levels and childhood asthma and wheezing. The association was assessed by generalized additive models and logistic regression models, and stratified analyses were performed to explore potential effect modifiers. A total of 12,384 vaccinated children participated in screening for asthma and wheezing, 236 cases were screened, as well as 1445 controls were randomized. After adjusting for the covariates, childhood asthma and wheezing were significantly associated with cold exposure in the first trimester, with OR 1.731 (95% CI: 1.117-2.628), and cold exposure and heat exposure in the third trimester, with ORs 1.610 (95% CI: 1.030-2.473) and 2.039 (95% CI: 1.343-3.048). In the third trimester, enhanced impacts were found among girls, children whose distance of residence was close to the nearest main traffic road, and children whose parents have asthma. The study indicates that exposure to extreme AT during the first and third trimesters could increase the risk of childhood asthma and wheezing., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The relationship between prenatal exposure to sulfur dioxide (SO 2 ) and childhood wheezing and asthma is unclear., Objective: To explore the association between prenatal exposure to SO 2 and childhood wheeze and asthma. To investigate the effects for the exposure during different pregnancy trimesters., Methods: We conducted a cross-sectional study firstly in Jinan City to get the prevalence of wheeze and asthma on children aged 18 months to 3 years. And then, we designed a case-control study based on population to evaluate the association between prenatal SO 2 exposure and childhood asthma and wheezing. Based on the starting and ending date of pregnancy and specific residential addresses, the individual concentrations of SO 2 during pregnancy was evaluated using an inverse distance weighted model., Results: The prevalence of wheeze and asthma on children aged 18 months to 3 years was 2.07% in our cross-sectional study. 236 cases and 1445 controls were available for exposure estimates. The OR (95% CI) of 1.296 (1.130-1.491) was significant after adjusting for the covariates. In the first and third trimesters, the effects were enhanced to 1.602 (1.275-2.022) and 1.448 (1.179-1.783) in the multi-pollutant model with adjusting the effects of other trimesters. Coincidentally, the SO 2 exposure level of the case in the first trimester was higher than that in the second and third trimesters (P < 0.001); however, there was no significant difference in exposure levels of the case between the second and third trimesters of pregnancy (P = 0.381)., Conclusion: Prenatal exposure to higher concentration of SO 2 could increase the risk of asthma and wheezing in younger children. The first trimester might be just the window for the toxic effect, while the third trimester was the sensitive window for the effect of SO 2 exposure during pregnancy on childhood asthma., (Copyright © 2021 Elsevier Inc. All rights reserved.)