Table 1. Distribution of bladder cancer cases (n = 140) and controls (n = 206) by demographical indicators, smoking habits, and risk professions for PAHs exposure.

	Cases (%)	Controls (%)	P
Gender			0.379
Male	120 (85.7)	168 (81.6)
Female	20 (14.3)	38 (18.4)
Age (years old)			0.067
<50	13 (9.3)	40 (19.4)
51–60	30 (21.4)	29 (14.1)
61–70	42 (30.0)	64 (31.1)
71–80	36 (25.7)	45 (21.8)
>80	19 (13.6)	28 (13.6)
Drinking habits
Non-carbonated soft drinks	8 (5.8)	17 (8.3)	0.380
Carbonated soft drinks	28 (20.0)	59 (28.6)	0.069
Coffee with caffeine	102 (72.7)	126 (61.2)	0.027
Coffee without caffeine	50 (35.7)	85 (41.3)	0.299
Tea	10 (7.1)	7 (3.4)	0.114
Beer	58 (41.4)	78 (37.9)	0.505
Wine	45 (32.1)	58 (28.2)	0.426
Other alcoholic beverages	26 (18.6)	33 (16.0)	0.536
Tap water	36 (25.7)	42 (20.4)	0.245
Bottled water without gas	96 (68.6)	138 (67.0)	0.758
Bottled water with gas	36 (25.7)	64 (31.1)	0.281
Smoking habit			<0.001
Non-smokers	22 (15.7)	72 (35.0)
Ex-smokers	54 (38.6)	25 (12.1)
Smokers	64 (45.7)	109 (52.9)
Packyears*			0.001
0	22 (15.7)	72 (35.0)
1–24.9	37 (26.4)	40 (19.4)
25–49.9	23 (16.4)	48 (23.3)
≧50	18 (12.9)	14 (6.8)
Age of onset of smoking			0.023
<15 years old	18 (12.9)	8 (3.9)
≧15 years old	99 (70.7)	121 (58.7)
Risk profession**			0.014
Yes	66 (47.1)	70 (34.0)
No	74 (52.9)	136 (66.0)
Type of risk profession
Farmer	26 (18.6)	28 (13.6)	0.210
Painter	8 (5.7)	3 (1.5)	0.050
Driver	25 (17.9)	20 (9.7)	0.027
Chemical industry	5 (3.6)	6 (2.9)	0.732
Tourism	9 (6.4)	14 (6.8)	0.893

P values obtained by chi-square-test.

^* Packyears = (number of cigarettes per years smoking)/20.

^** Farmer, painter, driver, chemical industry and tourism were considered as risk professions, grouped into one variable.