The causal and independent effect of ozone exposure during pregnancy on the risk of preterm birth: Evidence from northern China

Bai, Shuoxin; Du, Shuang; Li, Haiping; Lin, Shaoqian; Zhao, Xiaodong; Wang, Zhaojun; Wang, Zhiping

doi:10.1016/j.envres.2022.113879

Cited by 13 publications

(3 citation statements)

References 55 publications

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“…The details of the Jinan birth cohort have been described in the previous literature. 16,17 The study was approved by the Ethics Committee of Preventive Medicine of Shandong University (Approved number: 20170315) with the informed consent of all participants.…”

Section: Source Of Populationmentioning

confidence: 99%

The Association Between Exercise During Pregnancy and the Risk of Preterm Birth

Zhang,

Xiao,

Bai

et al. 2024

IJWH

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We aimed to examine the association between exercise during pregnancy and preterm birth (PTB). Methods: This study was a baseline survey of the Jinan birth cohort. The study subjects were the mothers one month after giving birth, which were investigated by questionnaires retrospectively containing physical exercise (frequency, time, and primary exercise patterns) during pregnancy and each trimester. Individual time spent on exercise and energy expenditure were assessed based on the questionnaires. PTB was clinically defined as a newborn born on or before the last day of the 37th week. Adjusted odds ratios (OR) were estimated using logistic regression to assess the relationship between exercise during pregnancy and the risk of PTB. Variable selection for the multivariate models was guided by the directed acyclic graph. The median effect was analyzed by the sequential test. Results:The prevalence of PTB in this study was 4.38% (285/6501). The adjusted OR (95% CI) for the risk of PTB related to exercise during pregnancy was 0.74 (0.58-0.95). During the 1st and 2nd trimesters, the ORs (95% CI) for 2.5 to 7 hours of exercise per week were 0.77 (0.59-0.99) and 0.74 (0.57-0.96). During the 3rd trimester, the ORs (95% CI) for 2.5 to 7 hours and more than 7 hours of exercise per week were 0.74 (0.56-0.96) and 0.65 (0.44-0.94). After stratifying the subjects, the association was only found among subjects without pregnancy complications. Pregnancy complications partially mediated (52.40%) the relationship between exercise during pregnancy and PTB. Conclusion: Exercise during pregnancy can reduce the risk of PTB for women without pregnancy complications. 2.5 to 7 hours of exercise (like walking) per week may be appropriate in three trimesters of pregnancy, and the time could be extended in the 3rd trimester.

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Section: Source Of Populationmentioning

confidence: 99%

The Association Between Exercise During Pregnancy and the Risk of Preterm Birth

Zhang,

Xiao,

Bai

et al. 2024

IJWH

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“…A number of studies have found association between environmental factors and preterm birth. Some studies have pointed that exposure to PM 2.5 (19), O 3 (20)and high temperature (21) could affect the risk of preterm birth.…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, the exposure levels of some environmental factors are different in different seasons. Speci cally, people are more likely to be exposed to high temperatures in summer and low temperatures in winter, and more likely to be exposed to high levels of PM 10 and PM 2.5 in winter as well as O 3 in summer (20,22). Therefore, it is important to consider the effect of the environmental factors on the risk of preterm birth when we explore the relationship between the season and preterm birth.…”

Section: Introductionmentioning

confidence: 99%

Role for Environmental Factors on the Relationship Between Seasons of Conception and Preterm Birth: An Observational Study in China

2024

Int Internal Med J

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Background: The relationship between season and the risk of preterm birth is not consistent. Importantly, the role of environmental factors in it is not clear. Methods: Based on the baseline of the Jinan birth cohort, the mothers from the birth cohort were the subjects, and they were interviewed face-to-face by the questionnaire. The individual exposure levels of temperature and humidity during the first 30 days of pregnancy were calculated by an inverse distance weighting method. The effect of season on the risk of preterm birth was obtained by logistic regression model, and the mediating effect of environmental factors in the association between season and preterm birth was obtained by sequential test. Results: A total of 4.4 % (263/5984) of mothers had premature children. The rates of preterm birth were higher in winter (6.0 %) and summer (4.5 %) than that in spring (3.1 %). In the multivariable logistic regression model, the adjusted odds ratio and 95 % confidence interval for the risk of preterm birth at conception in winter and summer were 2.228 (1.512-3.316) and1.541 (1.055-2.277). However, after further adjustment for humidity, only the association between winter conception and preterm birth remained statistically significant (OR: 2.353, 95% CI: 1.594-3.511). Moreover, the humidity partially mediated the relationship (41.2 %) between conception in winter and preterm birth, and humidity in winter was negatively associated with the risk of preterm birth (indirect effect = -0.007, P < 0.001). Conclusions: For women living in the temperate regions, conception in summer and winter may increase the risk of preterm birth, and this association persisted in winter after adjusting for environmental factors. During the first 30 days of pregnancy, lower levels of humidity exposure in winter contributed to and mediated the relationship. The results may provide epidemiological evidence for pregnancy planning and care of women from the perspective of environmental factors.

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