Environmental tobacco smoke (ETS) is generally known as secondhand smoke. Assessing the magnitude of children’s exposure to ETS from early infancy is essential for public health and research endeavours. Urinary cotinine is now widely recognised as the primary indicator for assessing exposure to ETS across all age groups. This systematic review and meta-analysis aim to synthesise all the published evidence on the urinary cotinine cut-off concentrations used to categorise children under 5 years as being exposed to ETS.

We will conduct a systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A comprehensive search will be conducted from various databases including PubMed, EMBASE, Scopus and Cochrane Library. This search will be performed from the earliest published articles up to the latest available studies until February 2025. We will include all the experimental and observational studies, such as cohort, case–control and cross-sectional, that measure urinary cotinine concentrations in children under 5 years old. Data extraction will be conducted using a standardised data extraction form, and the study quality will be evaluated according to the guidelines specified by the Newcastle-Ottawa Scale. The extracted data will be pooled and combined for meta-analysis. Two reviewers will independently screen, select and assess the quality of the included study. The result will be tabulated in a table of characteristics of the included study, which consists of the cut-off cotinine concentrations, analytical technique, method referred, study design, study area and respondents’ characteristics.

Ethics approval is not required as this is a review of collected published data. Findings will be disseminated in peer-reviewed publications and conference presentations, as well as with key stakeholders, health policymakers and healthcare professionals.

CRD42024556969.

Increasing awareness of the high frequency, wide spectrum and disabling nature of symptoms that can persist following COVID-19 infection has prompted the investigation of management strategies. Our study aims to determine the effectiveness of atorvastatin on cognitive function, physical activity, mood, health-related quality of life and features of neurovascular impairment and neuroinflammation in adults with ongoing neurological symptoms after COVID-19 infection.

The STatin TReatment for COVID-19 to Optimise NeuroloGical recovERy study is an ongoing international, investigator-initiated and conducted, multicentre, prospective, randomised, open label, blinded endpoint trial with fixed time points for outcome assessments. A total of 410 participants with long covid neurological symptoms were planned to be randomly assigned to either the intervention group to receive 40 mg atorvastatin for 12 months or to a control group of no treatment, on top of usual care.

This study protocol was designed, implemented and reported, in accordance with the International Conference on Harmonisation guidelines for Good Clinical Practice, the National Health and Medical Research Council of Australia, the National Statement on Ethical Conduct in Human Research and with the ethical principles laid down in the World Medical Association Declaration of Helsinki. Central ethics committee approval was obtained from Sydney Local Health District Royal Prince Alfred Hospital Ethics (No: X21-0113 and 2021/ETH00777 10) in Australia. Site-specific ethics committee approvals were obtained elsewhere before any local study activities. All participants provided written informed consent.

The study protocol is registered at Clinicaltrials.gov (NCT04904536).