In 2020, approximately 878,348 new cases of head and neck cancer (HNC) and approximately 444,347 HNC-related deaths were reported worldwide [1]. Among these, 377,713 new cases and 177,757 deaths were due to oral cancer [1]. Notably, 264,211 of these new cases and 125,022 of these oral cancer–related deaths were reported in men [1], [2]. In 2021, Taiwan reported 3395 oral cancer–related deaths, with a standardized mortality rate of 8.5 per 100,000 individuals, and oral cancer ranked sixth among deaths due to all cancer types in Taiwan [3]. Among men, HNC ranked fourth in terms of the standardized incidence rate among the ten most common cancer types causing death, with a standardized mortality rate of 16.5 per 100,000 [3]; the corresponding standardized mortality rate among women was only 1.2 per 100,000 [3].

Squamous cell carcinomas (SCCs) originating in the mucosal epithelium of the oral cavity, oropharynx, hypopharynx, or larynx account for the majority of HNC cases [4]. Heavy cigarette smoking and alcohol consumption are associated with HNC [5], and habitual betel nut chewing exhibits a distinct association with the occurrence and development of HNC, particularly oral cancer [6], [7]. According to the 2017 National Health Interview Survey conducted among the adult population in Taiwan [8], the prevalence of cigarette smoking was 29.4% in men and 4.2% in women, that of alcohol consumption was 37.0% in men and 19.5% in women, and that of betel nut chewing was 9.3% in men and 0.7% in women. However, the relationship between HNC-related mortality and alcohol consumption, betel nut chewing, and cigarette smoking (ABC) has not been thoroughly explored. In 2014, Sharp et al. [9] reported a significantly increased risk of cancer-related mortality (hazard ratio [HR] = 1.49, 95% confidence interval [CI] = 1.25–1.79) in patients with HNC who smoked habitually at the time of their diagnosis. In a cohort study conducted in Finland, Denissoff et al. [10] reported that persistent alcohol consumption (10–20 units per week) after a diagnosis of head and neck SCC (HNSCC) significantly increased the risk of mortality (HR = 1.44, 95% CI = 1.16–1.78). In Taiwan, Lee et al. [11] highlighted the significant effect of betel nut chewing on the prognosis of patients with SCC of buccal mucosa. However, large-scale population-based studies exploring the effect of ABC habits on HNC-related mortality rates are lacking. Accordingly, the present nationwide population-based cohort study examined data from 31,246 patients with HNC to determine the effects of ABC habits on HNC survival among the Taiwanese population.