Genome-wide association study summary statistics of email contact and Mental Health Questionnaire participation in UK Biobank. Data in support of the manuscript: "Factors associated with sharing email information and mental health survey participation in large population cohorts". **ABSTRACT** BACKGROUND People who opt to participate in scientific studies tend to be healthier, wealthier, and more educated than the broader population. While selection bias does not always pose a problem for analysing the relationships between exposures and diseases or other outcomes, it can lead to biased effect size estimates. Biased estimates may weaken the utility of genetic findings because the goal is often to make inferences in a new sample (such as in polygenic risk score analysis). METHODS We used data from UK Biobank, Generation Scotland, and Partners Biobank and conducted phenotypic and genome-wide association analyses on two phenotypes that reflected mental health data availability: (1) whether participants were contactable by email for follow-up and (2) whether participants responded to follow-up surveys of mental health. RESULTS In UK Biobank, we identified nine genetic loci associated (P < 5 × 10-8) with email contact and 25 loci associated with mental health survey completion. Both phenotypes were positively genetically correlated with higher educational attainment and better health and negatively genetically correlated with psychological distress and schizophrenia. One SNP association replicated along with the overall direction of effect of all association results. CONCLUSIONS Recontact availability and follow-up participation can act as further genetic filters for data on mental health phenotypes.adams-ukb-email_contact-1812.txt.gz: GWAS summary statistics of email contact in UK Biobank. adams-ukb-mhq_participation-1812.txt.gz: GWAS summary statistics of Mental Health Questionnaire participation in UK Biobank README: information on file headers and GWAS model