. 2016 Oct 25;11(10):e0164937. doi: 10.1371/journal.pone.0164937

Table 4. The association between the use of alcohol, betel quid, and cigarette and risk of head and neck cancer.

Use of alcohol, betel quid, and cigarette	Cases n (%)	Controls n (%)	OR (95% CI)^a
No use	20 (4.1)	141 (22.9)	Referent
Betel quid plus either alcohol or cigarette	87 (17.9)	57 (9.2)	8.12 (4.49–14.70)
Betel quid plus both alcohol and cigarette	270 (55.6)	112 (18.2)	14.35 (8.41–24.49)
Other combinations^b	109 (22.4)	306 (49.7)	2.30 (1.37–3.89)

Abbreviations: CI = confidence interval; OR = odds ratio

^a OR and 95% CI were calculated using unconditional logistic regression, adjusted for age and education.

^b Other combinations included other combinations of alcohol, betel quid, and cigarette, including alcohol only, betel quid only, cigarette only, and alcohol + cigarette.