An app promoting weight gain prevention via healthy behaviours amongst young women with a family history of breast cancer: Acceptability and usability assessment.

Background: Breast cancer is the most frequent female malignancy in the UK. Around 20% of cases are linked to weight gain, excess weight and health behaviours. We designed a weight gain prevention, health behaviour intervention for young women at increased risk. Methods: The study comprised a single arm observational study over 2 months testing acceptability and usability of the intervention: online group welcome event, app and private Facebook group. Females aged 18–35 years at moderate or high risk of breast cancer (>17% lifetime risk) were recruited via invite letters and social media posts. The app included behaviour change techniques and education content. Online questionnaires were completed at baseline, as well as at 1 and 2 months. We also assessed feasibility of study procedures. Results: Both recruitment methods were successful. Thirty‐five women were recruited, 26% via social media posts. Median age was 33 (interquartile range = 28.2–34.5) years, the majority (94.1%) were of White ethnicity. Thirty‐four participants were included in the analyses, of which 94% downloaded the app. Median self‐monitoring logs per participant during the study period was 10.0 (interquartile range = 4.8–28.8). App quality mean (SD) score was 3.7 (0.6) at 1 and 2 months (scale: 1–5). Eighty‐nine per cent rated the app at average or above at 1 month and 75.0% at 2 months. Nineteen women (55.9%) joined the Facebook group and there were 61 comments and 83 reactions and votes from participants during the study period. Conclusions: This first iteration of the app and intervention was well received and is suitable to progress to the next stage of refining and further testing. Highlights: The newly developed intervention that focused on weight gain prevention and health behaviour change was tested in young women at increased risk of breast cancer and was well‐received by the target population.Both recruitment methods, by mailshot and social media, were successful.The study was unable to recruit and ethnically diverse population.Future research should retest the intervention in a larger population, after making refinements. [ABSTRACT FROM AUTHOR]