Polycyclic aromatic hydrocarbons: determinants of urinary 1-hydroxypyrene glucuronide concentration and risk of colorectal cancer in the Shanghai Women’s Health Study

Table 2 Risk of colorectal cancer in relation to creatinine-adjusted urinary 1-OHPG concentration ^a

1-OHPG^b	N_cases	N_controls	Unadjusted OR (95% CI)	Adjusted OR (95% CI) ^c
Colorectal cancer
Q1: <0.10	89	86	Ref	Ref
Q2: ≥0.10 to <0.196	100	86	1.11 (0.74-1.68)	1.11 (0.73-1.71)
Q3: ≥0.196 to <0.331	80	86	0.89 (0.58-1.37)	0.88 (0.56-1.38)
Q4: ≥0.331	74	85	0.84 (0.55-1.30)	0.85 (0.54-1.33)
			P _trend = 0.3	P _trend = 0.3
Per 1-unit increase in 1-OHPG^d			0.98 (0.95-1.02)	0.98 (0.95-1.02)
Colon cancer
Q1: <0.10	54	48	Ref	Ref
Q2: ≥0.10 to <0.196	59	53	0.96 (0.56-1.64)	0.93 (0.53-1.65)
Q3: ≥0.196 to <0.331	50	51	0.84 (0.47-1.50)	0.77 (0.41-1.46)
Q4: ≥0.331	42	53	0.70 (0.39-1.24)	0.69 (0.40-1.29)
			P _trend = 0.2	P _trend = 0.2
Per 1-unit increase in 1-OHPG^d			0.98 (0.93-1.03)	0.98 (0.93-1.03)
Rectal cancer
Q1: <0.10	35	38	Ref	Ref
Q2: ≥0.10 to <0.196	41	33	1.35 (0.70-2.61)	1.43 (0.70-2.93)
Q3: ≥0.196 to <0.331	30	35	0.95 (0.49-1.83)	0.93 (0.46-1.87)
Q4: ≥0.331	32	32	1.08 (0.56-2.09)	1.09 (0.54-2.21)
			P _trend = 0.9	P_trend = 0.9
Per 1-unit increase in 1-OHPG^d			0.99 (0.92-1.07)	0.98 (0.91-1.07)

Abbreviations: 1-OHPG 1-hydroxypyrene glucuronide, OR odds ratio, CI confidence interval.
^a Quartiles were determined based on the distribution of creatinine-adjusted 1-OHPG measurements among controls.
^b μmol/mol creatinine.
^c Adjusted for the following covariates: age, education, smoking status, aspirin use, fruit intake, vegetable intake, folate intake, measured body mass index (BMI), leisure time physical activity, and occupational physical activity.
^d A 1-unit increase was defined as half of the difference between the 25^th and 75^th percentiles for creatinine-adjusted 1-OHPG measurements among controls.

ISSN: 1471-2407