Alcohol intake is associated with a decreased risk of developing primary biliary cholangitis

Table 3 Odds ratios for the association between tobacco and marijuana intake and primary biliary cholangitis development

	Controls (n = 200), n (%)	Cases (n = 200), n (%)	Univariable	Adjusted1	Adjusted2
Ever smoked tobacco prior to PBC diagnosis
No	116 (58.0)	89 (44.5)	1.00 [Reference]	1.00 [Reference]
Yes	84 (42.0)	111 (55.5)	1.73 (1.15, 2.59)	1.42 (0.88, 2.30)
			P = 0.008	P = 0.15
Age started smoking tobacco
Never smoker	115 (57.8)	88 (44.2)	1.00 [Reference]	1.00 [Reference]
10-15	19 (9.6)	24 (12.1)	1.66 (0.79, 3.47)	1.16 (0.49, 2.74)
> 15-17	30 (15.1)	35 (17.6)	1.59 (0.87, 2.91)	1.15 (0.57, 2.31)
> 17-19	19 (9.6)	26 (13.1)	1.66 (0.87, 3.16)	1.72 (0.79, 3.73)
> 19-38	16 (8.0)	26 (13.1)	2.23 (1.10, 4.53)	2.16 (0.97, 4.83)
Trend			P = 0.008	P = 0.022
Years smoking tobacco prior to PBC diagnosis
Never smoker	115 (57.8)	88 (44.2)	1.00 [Reference]	1.00 [Reference]
0-10	28 (14.1)	23 (11.6)	1.15 (0.63, 2.09)	1.07 (0.54, 2.13)
> 10-20	26 (13.1)	32 (16.1)	1.63 (0.89, 3.00)	1.18 (0.58, 2.38)
> 20-35	22 (11.1)	41 (20.6)	2.46 (1.33, 4.55)	2.27 (1.12, 4.62)
> 35-59.9	8 (4.0)	15 (7.5)	2.47 (1.01, 6.06)	1.90 (0.68, 5.30)
Trend			P = 0.001	P = 0.018
Ever smoked marijuana prior to PBC diagnosis
No	184 (92.0)	179 (89.5)	1.00 [Reference]	1.00 [Reference]	1.00 [Reference]
Yes	16 (8.0)	21 (10.5)	1.36 (0.68, 2.71)	1.45 (0.66, 3.20)	1.27 (0.56, 2.87)
			P = 0.39	P = 0.36	P = 0.56
Marijuana smoking status (constrained to starting smoking marijuana prior to PBC diagnosis)
Never smoker	184 (92.0)	179 (89.5)	1.00 [Reference]	1.00 [Reference]	1.00 [Reference]
Ex-smoker	16 (8.0)	19 (9.5)	1.21 (0.60, 2.46)	1.23 (0.55, 2.79)	1.10 (0.48, 2.55)
Current smoker	0 (0)	2 (1.0)	-	-	-

Associations with case status assessed by conditional logistic regression, grouped on the linkage identifier for matched cases and controls.

¹Adjusted models adjusted for whether participant was born in Australia and education completed.

²Adjusted models adjusted for whether participant was born in Australia, education completed, and whether participant had ever smoked tobacco.

PBC: Primary biliary cholangitis.