Conventional cigarettes, novel heated tobacco products, and self‐reported frequent headache association in Japanese individuals: Insights from the JASTIS study, a Japanese cross‐sectional analysis

OBJECTIVES/BACKGROUND: Heated tobacco products (HTPs) are novel alternatives to conventional cigarettes that heat tobacco leaves to generate nicotine-containing aerosols for inhalation. This study aimed to investigate the association between both conventional cigarette use and HTP use with self-reported frequent headache. Although the association between cigarette smoking and headache has been reported, evidence regarding HTPs remains limited. METHODS: We utilized data from the Japan Society and New Tobacco Internet Survey, an ongoing internet-based cohort cross-sectional study launched in 2015 to monitor conventional cigarette and HTP use. Participants were recruited from a nationally representative online panel, comprising over 2 million individuals. Among 28,000 respondents in the 2025 wave, we included 23,228 individuals with valid responses. Self-reported frequent headache was defined as responding "occasionally" or "frequently" to the question, "Have you experienced headaches in the past year?" (other options: "never" and "rarely"). We conducted a multivariable analysis adjusting for demographic, socioeconomic, lifestyle, and clinical variables. We then compared the adjusted odds ratios (aORs) of conventional cigarettes and HTP use for the prevalence of self-reported frequent headache. RESULTS: Of the 23,228 participants, 25.5% (5923/23,228) reported headaches. Regarding tobacco use, 12.2% (2823/23,228) were current cigarette users, 31.8% (7393/23,228) were former cigarette users, 56.0% (13,012/23,228) were never cigarette users; 11.6% (2688/23,228) were current HTP users, 10.0% (2326/23,228) were former HTP users, and 78.4% (18,214/23,228) were never HTP users. Multivariable analysis with multiple imputation revealed that current (aOR = 1.71 [95% confidence interval [CI] = 1.44-2.03]) and former (aOR = 1.54 [95% CI = 1.37-1.73]) cigarette use, and current (aOR = 1.15 [95% CI = 1.01-1.32]) HTP use were significantly associated with self-reported frequent headache. Former HTP use was not significantly associated with headache (aOR = 1.09 [95% CI = 0.96-1.24]). Postestimation comparisons indicated a weaker association for HTPs than for cigarettes (current smokers vs. current HTP users: ratio of aORs = 1.48 [95% CI = 1.19-1.84]). CONCLUSION: Both current and former cigarette use were significantly associated with a higher prevalence of self-reported frequent headache, and current HTP use also showed a modest but significant association. Although HTPs are often perceived as less harmful, they still emit nicotine and other constituents, which may be associated with self-reported frequent headache.