1 Department of Psychology, Université du Québec à Montréal, Case Postale 8888, succursale Centre-Ville, Montréal, Québec H3C 3P8.
2 Faculty of Medicine and Health Sciences, Université de Sherbrooke, Campus de Longueuil, 150 Place Charles-Le Moyne, Bureau 200, Longueuil, Québec J4K 0A8, Canada.
3 Department of Psychoeducation, Université du Québec à Trois-Rivières, Local 1064c Pavillon Michel-Sarrazin, 3351 Boulevard des Forges, C.P.500, Trois-Rivières, Québec G9A 5H7, Canada.
4 Department of Sociology and Anthropology, Concordia University (H-1125-31), 1455 De Maisonneuve West, Montréal, Québec H3G 1M8, Canada.
5 Department of Psychology, Université de Montréal, Pavillon Marie-Victorin, 90 avenue Vincent d'Indy, Montréal, Québec H2V 2S9, Canada.

Online poker is considered more at-risk than land-based poker in terms of intense gambling behaviors and gambling problems. The development of many online gambling sites has raised public health concerns about the potential increase in online poker players. Longitudinal studies are useful to better understand the evolution of gambling behaviors; however, very few consider online poker players. Using a prospective design, this study aims to identify online and land-based trajectories over a two-year period and the factors influencing those trajectories. Results are based on data collected at three time-points over the course of a prospective cohort study conducted in Quebec (n = 304). A latent class growth analysis was performed to determine trajectories based on the main poker modality played, either online or land-based poker. Multinomial multivariable logistic regression analyses were conducted to determine the correlates of poker playing trajectories. Over two years, three poker playing trajectories were identified, comprising two stable trajectories [stable land-based (51.5%) and stable online (36.3%)] and an unstable trajectory [unstable online land-based (12.1%)]. The second trajectory included online poker players at baseline who transitioned to land-based poker. Number of gambling activities increased the odds of being in the first trajectory as compared to the others. Severity of gambling problems was a significant predictor of the second "unstable" or the third "stable online" trajectories, but not for the first "stable land-based" poker trajectory. The majority of poker players remained in either the land-based or online trajectories over two years. No poker players transitioned from land-based to online poker.