“OC09 | TOBACCO NICOTINE-RELATED HEADACHE AS A CANDIDATE PHENOTYPE FOR ICHD-4: INSIGHTS FROM THE JASTIS STUDY, A JAPANESE CROSS-SECTIONAL ANALYSIS: M. Katsuki1|2, M. Romozzi3|4, Y. Matsumori5, K. Moran2, T. Ward2, T. Tabuchi7 | 1Nagaoka University of Technology, Japan; 2Insight Research Ireland Centre for Data Analytics, Ireland; 3Università Cattolica del Sacro Cuore, Italy; 4Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Italy; 5Sendai Headache and Neurology Clinic, Japan; 6Tohoku University, Japan”. 2026. Confinia Cephalalgica 36 (s1). https://doi.org/10.4081/cc.2026.15947.