Pre-COVID-19 pandemic health-related behaviours in children (2018-2020) and association with being tested for SARS-CoV-2 and testing positive for SARS-CoV-2 (2020-2021): a retrospective cohort study using survey data linked with routine health data in Wales, UK
Authors: Marchant Emily , Lowthian Emily , Crick Tom , Griffiths Lucy , Fry Richard , Dadaczynski Kevin , Okan Orkan , James Michaela , Cowley Laura , Torabi Fatemeh , Kennedy Jonathan , Akbari Ashley , Lyons Ronan , Brophy Sinead 
Published: January 2022

ABSTRACTObjectivesExamine if pre-COVID-19 pandemic (prior March 2020) health-related behaviours during primary school are associated with i) being tested for SARS-CoV-2 and ii) testing positive between 1 March 2020 to 31 August 2021.DesignRetrospective cohort study using an online cohort survey (January 2018 to February 2020) linked to routine PCR SARS-CoV-2 test results.SettingChildren attending primary schools in Wales (2018-2020), UK who were part of the HAPPEN school network.ParticipantsComplete linked records of eligible participants were obtained for n=7,062 individuals. 39.1% (n=2,764) were tested (age 10.6±0.9, 48.9% girls) and 8.1% (n=569) tested positive for SARS-CoV-2 (age 10.6±1.0, 54.5% girls).Main outcome measuresLogistic regression of health-related behaviours and demographics were used to determine Odds Ratios (OR) of factors associated with i) being tested for SARS-CoV-2 and ii) testing positive for SARS-CoV-2.ResultsConsuming sugary snacks (1-2 days/week OR=1.24, 95% CI 1.04 – 1.49; 5-6 days/week 1.31, 1.07 – 1.61; reference 0 days) can swim 25m (1.21, 1.06 – 1.39) and age (1.25, 1.16 – 1.35) were associated with an increased likelihood of being tested for SARS-CoV-2. Eating breakfast (1.52, 1.01 – 2.27), weekly physical activity ≥ 60 mins (1-2 days 1.69, 1.04 – 2.74; 3-4 days 1.76, 1.10 – 2.82, reference 0 days), out of school club participation (1.06, 1.02 – 1.10), can ride a bike (1.39, 1.00 – 1.93), age (1.16, 1.05 – 1.28) and girls (1.21, 1.00 – 1.46) were associated with an increased likelihood of testing positive for SARS-CoV-2. Living in least deprived quintiles 4 (0.64, 0.46 – 0.90) and 5 (0.64, 0.46 – 0.89) compared to the most deprived quintile was associated with a decreased likelihood.ConclusionsAssociations may be related to parental health literacy and monitoring behaviours. Physically active behaviours may include co-participation with others, and exposure to SARS-CoV-2. A risk versus benefit approach must be considered given the importance of health-related behaviours for development.STRENGTHS AND LIMITATIONSInvestigation of the association of pre-pandemic child health-related behaviour measures with subsequent SARS-CoV-2 testing and infection.Reporting of multiple child health behaviours linked at an individual-level to routine records of SARS-CoV-2 testing data through the SAIL Databank.Child-reported health behaviours were measured before the COVID-19 pandemic (1 January 2018 to 28 February 2020) which may not reflect behaviours during COVID-19.Health behaviours captured through the national-scale HAPPEN survey represent children attending schools that engaged with the HAPPEN Wales primary school network and may not be representative of the whole population of Wales.The period of study for PCR-testing for and testing positive for SARS-CoV-2 includes a time frame with varying prevalence rates, approaches to testing children (targeted and mass testing) and restrictions which were not measured in this study.