Background:
Previous research has found that small shops are frequently visited by young people and product exposures in this environment influence their health-related behaviours. Evidence from cross-sectional research suggests that recall of seeing e-cigarettes in small shops is associated with adolescent experimentation with e-cigarettes. This study is the first to explore these relationships with longitudinal follow up.

Methods:
Data are from the Determining the Impact of Smoking Legislation among Youth (DISPLAY) study. A prospective cohort survey was conducted in 4 high schools in Scotland UK during spring 2015 (n=3807) with follow up 1 year later. Analysis was restricted to young people who had never used an e-cigarette in 2015 (n= 2839) and 2388 of these (84%) provided their e-cigarette status in 2016.

Results:
At baseline 636 (22.6%) of young never e-cigarette users recalled seeing e-cigarettes for sale in small shops in the last 30 days. In a logistic regression the adjusted odds ratio for e-cigarette experimentation by follow up was 1.50 (95% CI 1.08 to 2.08) for young people who recalled seeing e-cigarettes in small shops compared to those who did not. The model was adjusted for recall of e- cigarettes in supermarkets, recall of e-cigarettes on the internet, recall of e- cigarettes adverts on other media (TV, radio, newspapers), having friends who smoke, having family members that smoke, young person's smoking status, sex, age, family affluence scale and school.

Conclusions:
Seeing e-cigarettes for sale in small shops may increase the likelihood that young people will experiment with them. The model was adjusted for noticing other forms of e-cigarette advertising so this corrects for the fact that young people who are already interested in e-cigarettes may be more likely to notice potential sources and information about e-cigarettes. The role of small retailers in normalizing novel nicotine product use in young people requires further investigation.