Table 1.

Association between smoking and risk of SLE.

	No. of Subjects (%)		OR (95% CI)
	Cases	Controls	Crude	p	Adjusted^*	p
Smoking status^**
Never smoker	98 (64.9)	338 (79.7)	1.0		1.0
Former smoker	46 (30.5)	68 (16.0)	2.33 (1.51–3.61)	< 0.0001	3.32 (2.00–5.53)	< 0.0001
Current smoker	7 (4.6)	18 (4.3)	1.34 (0.54–3.30)	0.523	1.46 (0.54–3.90)	0.455
Ever smoker	53 (35.1)	86 (20.3)	2.12 (1.41–3.20)	< 0.0001	2.86 (1.78–4.60)	< 0.0001
Cumulative exposure^†
Never smokers	98 (67.1)	338 (80.7)	1.0		1.0
< 1 pack-year	13 (8.9)	32 (7.6)	1.40 (0.71–2.77)	0.333	2.19 (1.05–4.57)	0.037
1 to ≤ 5 pack-years	18 (12.3)	26 (6.2)	2.39 (1.26–4.54)	0.008	3.09 (1.49–6.43)	0.003
> 5 pack-years	17 (11.6)	23 (5.5)	2.54 (1.31–4.96)	0.006	3.22 (1.45–7.14)	0.004
				p for trend < 0.0001		p for trend < 0.0001

↵* Adjusted for age, region, and alcohol intake.
↵** Four women (1 case and 3 controls) were missing smoking status data.
↵^† Fourteen women (8 cases and 6 controls) were missing cumulative exposure data.