Daily alcohol consumption trajectories and user retention during a national temporary abstinence campaign: real-world data from a smartphone application

Temporary Abstinence Challenges (TAC), such as Dry January, are widely implemented public health initiatives and have been associated with short- and medium-term reductions in alcohol consumption. Smartphone applications are increasingly recommended to support participation, yet little is known about real-world user engagement and day-to-day drinking trajectories during these campaigns. This study examined patterns of app use, retention, and alcohol consumption among users of a smartphone application during the 2024 national “Défi de janvier” campaign in France. We conducted an observational analysis of anonymized, app-based self-reported data collected between 1 and 31 January 2024. Daily alcohol consumption and engagement were analyzed among 2,032 adult users according to age, sex, and baseline World Health Organization (WHO) drinking-risk level assessed during a reference week preceding the campaign. User retention was examined using Cox proportional hazards models, and changes in alcohol consumption were analyzed using daily trajectories and linear mixed-effects models. Higher baseline WHO drinking-risk levels and younger age were independently associated with lower retention, whereas sex and binge drinking during the reference week were not. Across all drinking-risk groups of users who remained engaged, alcohol consumption followed a stable weekly pattern with peaks on Fridays and Saturdays. Among users with available data over time, mean self-reported daily alcohol consumption decreased over January across baseline risk categories. Absolute reductions were greatest among users with higher baseline consumption, while individuals with lower-risk drinking showed smaller but consistent decreases. In this large real-world sample of smartphone application users participating in a national temporary abstinence challenge, alcohol consumption declined among users who remained engaged and across all baseline drinking-risk levels, despite substantial variability in user retention. These findings provide real-world evidence on engagement patterns and self-reported drinking trajectories among users of a digital tool during a national Temporary Abstinence Challenge, and highlight opportunities to optimize future interventions, particularly for younger users and those with higher baseline drinking levels.