Association between tobacco exposure and bladder cancer recurrence: A systematic review and meta-analysis

Table 3 Summary of meta-analysis results on smoking status and disease recurrence in patients with bladder cancer

Analysis specification	n	Tobacco exposure vs never smoking		Current smoker vs never smoker		Former smoker vs never smoker		Current smoker vs former smoker
		OR (95%CI)	I2 (%)	OR (95%CI)	I2 (%)	OR (95%CI)	I2 (%)	OR (95%CI)	I2 (%)
All	12	1.84 (1.15-2.93)	91	1.85 (1.11-3.07)	91	1.73 (1.09-2.73)	88	1.01 (0.74-1.38)	83
Race			91		90		88		83
Caucasian	7	1.33 (1.12-1.58)		1.32 (1.09-1.59)		1.29 (1.07-1.56)		1.03 (0.89-1.18)
Noncaucasian	5	2.13 (1.74-2.61)		2.24 (1.78-2.83)		1.76 (1.39-2.23)		1.16 (0.93-1.45)
Study design			91		91		88		83
Multi	6	1.98 (1.68-2.32)		2.07 (1.73-2.48)		1.67 (1.39-2.01)		1.21 (1.04-1.40)
Single	5	1.09 (0.87-1.37)		1.00 (0.78-1.30)		1.12 (0.87-1.43)		0.81 (0.65-1.00)
Sort			91				88		84
Retrospective	5	3.23 (2.59-4.02)		3.23 (2.52-4.14)		3.15 (2.44-4.08)		1.04 (0.83-1.32)
Forward	6	1.05 (0.89-1.24)		1.09 (0.91-1.32)		0.97 (0.81-1.17)		1.10 (0.95-1.28)
Disease stage			91		91		88		83
NMBIC	10	1.93 (1.65-2.26)		1.83 (1.54-2.18)		1.81 (1.52-2.15)		0.94 (0.81-1.09)
Others	2	1.00 (0.78-1.29)		1.20 (0.91-1.59)		0.85 (0.65-1.12)		1.38 (1.11-1.72)
Research cycle			91		91		88		83
End of before 2010	5	1.26 (1.01-1.56)		1.22 (0.95-1.56)		1.25 (0.99-1.59)		0.93 (0.76-1.14)
End after 2010	7	1.88 (1.59-2.21)		1.92 (1.60-2.31)		1.59 (1.32-1.92)		1.14 (0.98-1.33)

OR: Odd ratios; I²: I-squared statistic; NMBIC: Non-muscle- invasive bladder cancer.