Combined Effect of Secondhand Smoking and Alcohol Drinking on Risk of Persistent Human Papillomavirus Infection

Table 2

Odds ratios for risk of HPV persistence of active smokers and secondhand smokers according to alcohol drinking status.

	HR-HPV infection at enrollment (n = 4,578)			1-year HR-HPV persistence (n = 527)			2-year HR-HPV persistence (n = 205)
Alcohol drinkers	Negative	Positive	Multivariate OR	Negative	Persistence	Multivariate OR	Negative	Persistence	Multivariate OR
	(n = 4,059)	(n = 519)	(95% CI)	(n = 447)	(n = 80)	(95% CI)	(n = 177)	(n = 28)	(95% CI)
Active tobacco smoking
Nonsmoking	3527 (88.9)	440 (11.1)	1 (ref.)	386 (84.8)	69 (15.2)	1 (ref.)	144 (84.7)	26 (15.3)	1 (ref.)
Smoking	532 (87.1)	79 (12.9)	1.14 (0.88–1.49) ^2)	61 (84.7)	11 (15.3)	0.92 (0.45–1.92)	33 (94.3)	2 (5.7)	0.30 (0.07–1.43)
for interaction			0.072 ^3)			0.586			0.257
Secondhand smoking (SHS)
Non-SHS	2402 (89.4)	285 (10.6)	1 (ref.)	250 (86.5)	39 (13.5)	1 (ref.)	98 (88.3)	13 (11.7)	1 (ref.)
SHS	1657 (87.6)	234 (12.4)	1.25 (1.06–1.47)	197 (82.8)	41 (17.2)	1.64 (1.09–2.48)	79 (84.0)	15 (16.0)	2.54 (1.25–5.17)
for interaction			0.005			0.012			0.029
SHS in nonactive smokers
Non-SHS	2092 (89.7)	240 (10.3)	1 (ref.)	218 (86.9)	33 (13.1)	1 (ref.)	82 (87.2)	12 (12.8)	1 (ref.)
SHS	1435 (87.8)	200 (12.2)	1.25 (1.05–1.48)	168 (82.4)	36 (17.6)	1.75 (1.14–2.68)	62 (81.6)	14 (18.4)	2.96 (1.42–6.15)
for interaction			0.003			0.004			0.006
	HR-HPV infection at enrollment (n =4,652 )			1-year HR-HPV persistence (n =639)			2-year HR-HPV persistence (n =252)
Alcohol nondrinkers	Negative	Positive	Multivariate OR	Negative	Persistence	Multivariate OR	Negative	Persistence	Multivariate OR
	(n = 4,242)	(n = 410)	(95% CI)	(n = 580)	(n = 59)	(95% CI)	(n = 231)	(n = 21)	(95% CI)
Active tobacco smoking
Nonsmoking	4076 (91.3)	387 (8.7)	1 (ref.)	555 (91.0)	55 (9.0)	1 (ref.)	222 (91.7)	20 (8.3)	1 (ref.)
Smoking	166 (87.8)	23 (12.2)	1.26 (0.81–1.96)	25 (86.2)	4 (13.8)	1.20 (0.39–3.65)	9 (90.0)	1 (10.0)	0.89 (0.11–7.48)
Secondhand smoking (SHS)
Non-SHS	2806 (91.0)	279 (9.0)	1 (ref.)	379 (89.4)	45 (10.6)	1 (ref.)	137 (89.5)	16 (10.5)	1 (ref.)
SHS	1436 (91.6)	131 (8.4)	0.70 (0.56–0.87)	201 (93.5)	14 (6.5)	0.40 (0.21–0.77)	94 (95.0)	5 (5.0)	0.52 (0.20–1.39)
SHS in nonactive smokers
Non-SHS	2701 (91.1)	265 (8.9)	1 (ref.)	361 (89.6)	42 (10.4)	1 (ref.)	134 (89.9)	15 (10.1)	1 (ref.)
SHS	1375 (91.8)	122 (8.2)	0.78 (0.64–0.95)	194 (93.7)	13 (6.3)	0.43 (0.23–0.77)	88 (94.6)	5 (5.4)	0.49 (0.19–1.29)

Enrollment HR-HPV infection indicates the HR-HPV infection at the time of enrollment. “Negative” or “Positive” indicates the result of detection for 13 DNA types of high risk-human papillomavirus (HR-HPV) (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68) using Hybrid Capture II.
One-year and 2-year HR-HPV persistence were defined as HPV positivity in the 1-year follow-up study year and as HPV positivity in both the 1- and 2-year follow-up study years, respectively, after enrollment with HR-HPV positivity. One- and 2-year HPV negatives were defined as HPV negativity in the 1-year follow-up study year and as HPV negativity in both the 1- and 2-year follow-up study years, respectively, after enrollment with HPV negativity.
Non-SHS indicates persons who are not exposed to secondhand smoking at home or in the workplace, regardless of active smoking status.
Secondhand smoking (SHS) in nonsmokers was defined as having never smoked in life but having been exposed to SHS.
All variables were adjusted for age, BMI, marital status, oral contraceptive use, menopausal status, education level, and number of children.
The p value represents the multiplicative interaction of two factors.