Table 5.

Smoking history of Primary Biliary Cirrhosis cases and controls.

	PBC	Controls	P-value*
Smoking
Ever regularly smoked cigarettes	53%	40%	< 0.001
Median age started smoking#	18.0 (10.0 – 58.0)	18.0 (12.0 – 50.0)	0.34
Currently smoking cigarettes regularly	14%	13%	0.29
Median years as regular smoker#	22.0 (1.0 – 56.0)	21.0 (0.0 – 60.0)	0.04
Median number pack years prior to PBC diagnosis#	10.5 (0.3 – 88.0)	--
Second-Hand Smoke Exposure
Ever lived with a smoker	81%	73%	0.01
Ever worked with a smoker	55%	50%	0.24

PBC: Primary Biliary Cirrhosis

^*adjusted for age at time of recruitment, gender, and education

^#variables summarized as median (min - max)