Synergistic effects of betel quid chewing, tobacco use (in the form of cigarette smoking), and alcohol consumption on the risk of malignant transformation of oral submucous fibrosis (OSF): a case-control study in Hunan Province, China

ObjectivesOral submucous fibrosis (OSF) is a potentially malignant disorder, wherein 7% to 13% of patients with OSF develop oral squamous cell carcinoma (OSCC) at clinically coincident sites established to have OSF. We aimed at investigating the lifestyle-related risk factors for malignant transformation of OSF.Study DesignA case-control study was conducted among 80 cases with OSF-associated OSCC and 80 controls with OSF but without clinically or histopathologically evident OSCC, recruited from January 2012 to October 2014 in the Xiangya Hospital, Hunan Province, Mainland China.ResultsThe odds ratios (OR) for OSCC were 13.3 (95% confidence interval [95% CI]: 3.1-56.4) and 45.1 (95% CI: 9.6-212.9) at the highest exposure of betel quid (BQ) chewing, by duration and frequency, respectively. Higher risks were also found to be associated with the consumption of cigarette (OR = 5.0, 95% CI: 1.7-14.8) and alcohol (OR = 3.1, 95% CI: 1.1-8.6). Adjusted ORs increased substantially among patients who consumed BQ and cigarette or alcohol simultaneously, which were 26.1 (95% CI: 4.0-172.6) and 55.-(95% CI: 1.8-1742.8) at the longest duration, and 160.3 (95% CI: 18.7-11371.2) and 58.1 (95% CI: 2.4-1434.9) at the highest dose, respectively.ConclusionsThe use of BQ, cigarette, and alcohol were identified as risk factors for malignant transformation of OSF in the Hunan province, Mainland China. Synergistic effects between BQ chewing and cigarette or alcohol consumption were revealed.