Table 2.

Bladder cancer risk (Odd Ratio [OR] and 95% confidence intervals) by quartiles of smoking metrics

		Crude Modela		Adjusted on cg05575921 (AHRR)		Adjusted on PC1b
		OR	p-value	OR	p-value	OR	p-value
Pack-years	Q1 vs Q2	1.823 (1.33, 2.50)	1.75e − 04	1.36 (0.98, 1.90)	6.95e − 02	1.328 (0.98, 1.89)	9.09e − 02
	Q1 vs Q3	2.981 (2.17, 4.11)	2.04e − 11	2.022 (1.43, 2.87)	7.38e − 05	2.013 (1.43, 2.87)	5.28e − 05
	Q1 vs Q4	2.933 (2.16, 4.00)	9.08e − 12	1.817 (1.28, 2.59)	9.24e − 04	1.751 (1.28, 2.56)	1.31e − 03
Duration (years)	Q1 vs Q2	2.283 (1.64, 3.20)	1.44e − 06	1.683 (1.18, 2.40)	3.97e − 03	1.628 (1.18, 2.40)	6.50e − 03
	Q1 vs Q3	3.751 (2.67, 5.30)	4.10e − 14	2.51 (1.73, 3.65)	1.36e − 06	2.474 (1.73, 3.65)	1.06e − 06
	Q1 vs Q4	3.465 (2.44, 4.95)	4.90e − 12	2.113 (1.42, 3.15)	2.36e − 04	2.061 (1.42, 3.15)	2.26e − 04
Intensity (packs/day)	Q1 vs Q2	2.703 (2.03, 3.62)	1.77e − 11	1.985 (1.46, 2.70)	1.15e − 05	2.036 (1.46, 2.70)	4.04e − 06
	Q1 vs Q3	2.636 (1.71, 4.07)	1.06e − 05	1.909 (1.22, 2.98)	4.43e − 03	1.913 (1.22, 2.98)	4.35e − 03
	Q1 vs Q4	2.551 (1.87, 3.48)	3.15e − 09	1.694 (1.21, 2.37)	2.10e − 03	1.657 (1.21, 2.37)	2.80e − 03

Results are also presented for the model additionally adjusted for the methylation level at cg05575921 (AHHR), the strongest CpG-site associated with smoking status in our dataset and on the first principal component (PC1) summarising the methylation levels at the 200 smoking-related CpG sites in our data

Quartile definition (sample size):

Pack-years: Q1: [0, 15[ (n = 383); Q2: [15, 31[ (n = 378); Q3: [31, 46[ (n = 381); Q4: [46, 184] (n = 403)

Duration (years): Q1: [0, 20[ (n = 359); Q2: [20, 34[ (n = 391); Q3: [34, 40[ (n = 322); Q4: [40, 59] (n = 473)

Intensity (packs/day): Q1: [0, 0.5[ (n = 300); Q2: [0.5, 1[ (n = 334); Q3: [1, 1.27[ (n = 522); Q4: [1.27, 4] (n = 389)

^aAll models were adjusted for age, sex and centre

^bPC1 explains 19.3% of the total variance