To evaluate the association between urinary 8-hydroxy-2'-deoxyguanosine (U8-OHdG) level—a marker of oxidative stress—and the incidence of preterm births (PTBs).

Prospective cohort study.

The Japan Environment and Children’s Study (JECS).

Data from 92 715 women with singleton pregnancies at and after 22 weeks of gestation who were enrolled in the JECS, a nationwide birth cohort study, between 2011 and 2014 were analysed. U8-OHdG levels were assessed once in the second/third trimester using liquid chromatography–tandem mass spectrometry. Participants were categorised into the following three or five groups: low (

Adjusted OR (aOR) for PTB before 37 and 34 weeks of gestation were calculated using a multivariable logistic regression model while adjusting for confounding factors; the moderate or lowest U8-OHdG group was used as the reference, respectively.

The aORs for PTB before 37 weeks of gestation in the high U8-OHdG group were 1.13 (95% CI 1.05 to 1.22) and 1.13 (95% CI 1.04 to 1.23) after stratification. The aOR for PTB before 37 weeks in the fourth group was 0.90 (95% CI 0.81 to 0.99). After stratification, the aORs for PTB before 37 and 34 weeks in the fifth group were 1.15 (95% CI 1.03 to 1.29) and 1.46 (95% CI 1.08 to 1.97), respectively.

High U8-OHdG levels were associated with increased PTB incidence, especially in participants without representative causes for artificial PTB. Our results can help identify the mechanisms leading to PTB, considering the variable aetiologies of this condition; further validation is needed to clarify clinical impacts.

The use of immune checkpoint inhibitors (ICIs) is rapidly expanding in cancer treatment. ICIs have a unique safety profile, characterised by immune-related adverse events (irAEs). The safety profile of ICIs lacks patient experience and perspectives. This study primarily aims to obtain a database for descriptive research on the status of irAEs using the Patient-Reported Outcomes version of the Common Terminology Criteria (PRO-CTCAE) in patients with gastrointestinal cancer, lung cancer and malignant pleural mesothelioma treated with regimens containing ICIs.

This is an ongoing, multicentre, observational study in Japan. Eligible patients must be at least 20 years old and have been diagnosed with lung cancer, malignant pleural mesothelioma or gastrointestinal cancer and plan to use ICIs. Participants will install the electronic PRO (ePRO) application and report adverse events via ePRO using PRO-CTCAE once weekly for up to 48 weeks. A registry will be established using background information obtained from medical records. The sample size is determined by 1 year projection without using statistical methods. Statistical analyses will include point estimates and 95% CIs for the incidence of each adverse event by cancer type and regimen at each time point.

This research will be conducted per the Declaration of Helsinki, the Ethical Guidelines for Life Science and Medical Research Involving Human Subjects issued by the Ministry of Education, Culture, Sports, Science and Technology and the Ministry of Health, Labor and Welfare, and the revised Personal Information Protection Law. The study protocol was approved by the Ethics Committee (approval ID T2021-0180) of Tokyo Medical University Hospital on 15 October 2021.

The study began enrolling patients in December 2021. The target enrolment is 260; as of October 2022, 141 have been enrolled, and the enrolment is scheduled to end on 30 June 2023.

UMIN000046418