Government-regulated workplace indoor smoking rooms for exclusive heated tobacco product (HTP) smoking in Japanese workplaces are associated with a higher likelihood of HTP smoking: the JASTIS 2024 study

OBJECTIVE: Despite the recommendation that heated tobacco products (HTPs) and conventional cigarettes (CCs) be regulated equivalently, Japan has adopted a national policy allowing some types of employers to institute workplace policies designating indoor HTP-only smoking rooms, in addition to the long-standing partial smoking ban system that allows smoking CCs and HTPs only inside smoking rooms. This study assessed whether employers' workplace policies regarding smoking were associated with employees' self-reported CC or HTP smoking. METHODS: In 2024, we conducted a nationwide internet-based survey of 12 625 workers. Relative risks (RRs) for current (past 30 days) CC and HTP smoking based on workplace policies were estimated using modified Poisson regression analysis, adjusted for demographic and behavioural characteristics. Workplace smoking policies were classified into three categories: complete bans on smoking CCs and HTPs, partial smoking bans with HTP-only smoking rooms and partial smoking bans without HTP-only smoking rooms. Additionally, we conducted stratified analyses to identify possible associations between workplace smoking policies and smoking CCs and HTPs within each stratum of characteristics. RESULTS: Compared with complete smoking bans, partial smoking bans with HTP-only smoking rooms were associated with a higher likelihood of HTP smoking (RR=1.55, 95% CI 1.35 to 1.77). This association was observed both among people who formerly (RR=1.88, 95% CI 1.51 to 2.33) and currently (RR=1.28, 95% CI 1.09 to 1.51) smoke CCs. CONCLUSIONS: The presence of HTP-only smoking rooms in workplaces likely resulted in more workers smoking HTPs. HTP-only smoking rooms should therefore be eliminated, and employers should completely prohibit CC and HTP smoking in their workplaces.