RT Journal Article SR Electronic T1 Associations between cohort study participation and self-reported health and well-being: the Northern Finland Birth Cohort 1966 Study JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP jech-2022-219229 DO 10.1136/jech-2022-219229 A1 Heli Taanila A1 Anna Reetta Rönkä A1 Sirkka Keinänen-Kiukaanniemi A1 Jari Jokelainen A1 Tanja Nordström A1 Anja Taanila A1 Tuula Hurtig YR 2022 UL http://jech.bmj.com/content/early/2022/09/07/jech-2022-219229.abstract AB Aim The aim of this study was to explore whether active participation in a longitudinal birth cohort study is associated with study participants’ health behaviour and well-being.Methods The subjects of this study were part of the Northern Finland Birth Cohort 1966. The follow-up data were collected through clinical examinations and questionnaires when the cohort members were 1, 14, 31 and 46 years old. In this study, cohort participation activity was divided into three categories: active, semiactive and least active.Results The total number of study participants who participated in the 46-year follow-up on both the survey and clinical trials was 6392, of which 66.5% (n=4268) participated actively in the cohort study. A total of 67.6% were female (p<0.001). Of the participants, 23.7% (n=1519) were semiactive and 9.5% (n=605) were the least active. Women who participated least actively experienced statistically significantly more depressive symptoms and poorer health, were more dissatisfied with their lives and had more addiction problems. In men, there was not a statistically significant association between participation activity and these well-being variables other than addiction problems and mental health.Conclusions The findings indicate that participation activity is associated with better self-reported health and well-being, especially among women. With this knowledge, people can be encouraged to participate in longitudinal health research and, at the same time, may improve their own health and quality of life.Data are available on reasonable request. Data may be obtained from a third party and are not publicly available. NFBC data is available from the University of Oulu, Infrastructure for Population Studies. Permission to use the data can be applied for research purposes via electronic material request portal. In the use of data, the University of Oulu follows the EU general data protection regulation (679/2016) and Finnish Data Protection Act.