Background The scientific value of large-scale prospective gene-environment interaction (GxE) studies is widely accepted. However, these studies are prohibitively expensive and few are conducted. This approach, therefore, remains under-exploited. The ability to conduct prospective GxE studies entirely remotely, that is, without direct participant contact, promises substantial cost savings and would increase our capacity to utilise this design.

Aim To investigate the feasibility of conducting GxE studies entirely remotely by recruiting older people to a pilot study of cognitive function and subjective well-being.

Methods A random sample of men and women aged 50+ years and living in Cardiff, South Wales were mailed inviting them to visit a website to join a study of successful ageing. Online consent was obtained for questionnaire completion, cognitive testing, re-contact, record linkage and genotyping. Cognitive testing was conducted using the Cardiff Cognitive Battery. Bio-sampling was randomised to blood spot, buccal cell or no request.

Results A heterogeneous sample of 667 men and women (50% female) aged 50–101 years (median=62 yrs) from diverse backgrounds (representing the full range of deprivation scores) was recruited. Bio-samples were donated by 70% of those agreeing to do so. Self-report questionnaires and cognitive tests showed comparable distributions to those collected using face-to-face methods.

Conclusion This study has demonstrated that remote methods can be used to recruit for GxE studies and provides encouragement that up-scaling these methods provides the means to conduct large-scale GxE studies cost-effectively.