DAGIS Salo cohort profile: a longitudinal and cross-sectional study to identify environmental and individual factors linked to health behaviours, recovery from stress, weight and learning outcomes among Finnish schoolchildren

Abstract Background The global prevalence of childhood obesity has increased significantly, with World Health Organisation emphasising the importance of early childhood for promoting healthy growth and development. In Finland, 29% of boys and 18% of girls aged 2–16 years are living with overweight or obesity. The DAGIS Intervention in 2017–2018 in Southwest Finland aimed to promote healthy energy-balance related behaviours (EBRBs) and self-regulation skills in early childhood education and family settings, hypothesising that improvements would reduce overweight prevalence, increase well-being, and enhance learning outcomes in pre-adolescence. DAGIS Salo is a follow-up study of the DAGIS Intervention, with parallel recruitment of a new cross-sectional sample. This paper describes the DAGIS Salo cohort profile, covering study design, recruitment, measurements, data processing and participant characteristics. Methods The DAGIS Salo study (2023–2024) consisted of a larger cross-sectional sample and, within it, a six-year follow-up sample from the DAGIS Intervention. All primary schoolchildren in grades 3–6 in Salo municipality in Southwest Finland and their caregivers were invited to participate, regardless of participation in the DAGIS Intervention. Schoolchildren provided information on movement behaviours (accelerometry), screen use, food consumption, psychosocial well-being, and recovery from stress (heart rate variability). Trained data collectors measured schoolchildren’s anthropometrics and administered learning tests. Caregivers provided information on physical and social home environment and child temperament. School and food service personnel provided information on the school environment. Results The DAGIS Salo cohort consists of 540 schoolchildren (27% of eligible participants), including the DAGIS Intervention follow-up sample of 207 schoolchildren (31% of participants from the DAGIS Intervention). The average age of schoolchildren in the cohort was 11 (± 1.15) years and 54% of participants were girls. Conclusion The DAGIS Salo study utilised a longitudinal and cross-sectional design, objective measures and validated instruments, and multiple perspectives to examine physical and social environments that influence schoolchildren’s health and behaviour. Study findings can advance equity in schoolchildren’s health, well-being and learning by identifying modifiable factors within early childhood education, home and school environments, to better support EBRBs, well-being and learning of those who need it most. Trial registration ISRCTN57165350 (8 January 2015).