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Abstract
Background Independent studies on exhaled carbon monoxide (CO) and saliva cotinine levels in regular heated tobacco product (HTP) users, and how they compare with conventional cigarette (CC) smokers, are lacking.
Methods A total of 3294 current users of CCs, HTPs or electronic cigarettes (ECs) from a household survey and a smoking hotspot survey were classified into seven groups: exclusive users of CCs, HTPs, ECs; dual users of CCs and HTPs, CCs and ECs, HTPs and ECs; and triple users. We measured exhaled CO level using the piCo Smokerlyzer (n=780) and saliva cotinine using NicAlert cotinine test strips (n=620). Among the seven groups, the differences in (1) CO and cotinine levels were examined using Kruskal-Wallis test, and (2) the average daily tobacco consumption in the past 30 days was examined using multivariable linear regression.
Results Both exclusive and dual users of CCs had a higher CO level than exclusive HTP or EC users (p<0.05). Exhaled CO levels were similar between HTP and EC users, as were saliva cotinine levels among the seven groups. Compared with exclusive CC users, those who also used HTPs or ECs smoked fewer CCs (CCs+HTPs: adjusted coefficient −2.79, 95% CI −3.90 to –1.69; CCs+ECs: −1.34, 95% CI −2.34 to –0.34), but consumed more tobacco sticks equivalent in total (2.79 (95% CI 1.61 to 3.96); 1.95 (95% CI 0.79 to 3.12)).
Conclusions HTP or EC use showed lower exhaled CO but similar saliva cotinine levels compared with CC use. Dual users of CCs and HTPs/ECs smoked fewer CCs than exclusive CC users, but consumed more tobacco in total.
- harm reduction
- cotinine
- non-cigarette tobacco products
Data availability statement
Data are available upon reasonable request. Data are available upon request to the corresponding authors at syho@hku.hk or gyysun@hku.hk.
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Data availability statement
Data are available upon reasonable request. Data are available upon request to the corresponding authors at syho@hku.hk or gyysun@hku.hk.
Footnotes
Contributors All authors conceptualised and designed the study. XZ analysed the data and wrote the first draft. YS coordinated the study. All authors critically reviewed and revised the manuscript, approved the final manuscript as submitted and agree to be accountable for all aspects of the work. SYH is responsible for the overall content and is the guarantor of this work.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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