	Quartiles of serum SepP concentration (mg/L)				Continuous (per 1 mg/L)
	<2.58	2.58-2.90	2.90-3.24	≥3.24	Continuous (per 1 mg/L)
Cases/controls (n)	61/121	53/124	74/119	59/127
Crude OR^* (95% CI)	1.00	0.84 (0.54, 1.33)	1.22 (0.79, 1.88)	0.91 (0.57, 1.44)	0.85 (0.62, 1.17)
Adjusted OR^† (95% CI)	1.00	0.83 (0.52, 1.33)	1.07 (0.68, 1.88)	0.83 (0.51, 1.33)	0.77 (0.55, 1.07)
Excluding cases diagnosed during 1^st year of follow-up (and matched controls)
Cases/controls (n)	58/116	50/116	68/115	58/118
Adjusted OR^† (95% CI)	1.00	0.85 (0.53, 1.36)	1.00 (0.63, 1.59)	0.88 (0.54, 1.43)	0.79 (0.56, 1.11)
High-grade prostate cancer
Cases/controls (n)	25/49	18/34	28/41	20/58
Adjusted OR^† (95% CI)	1.00	0.98 (0.46, 2.06)	1.13 (0.55, 2.29)	0.57 (0.27, 1.22)	0.62 (0.37, 1.05)
Low-grade prostate cancer
Cases/controls (n)	33/66	27/71	37/64	33/56
Adjusted OR^† (95% CI)	1.00	0.75 (0.39, 1.44)	1.08 (0.57, 2.04)	1.07 (0.55, 2.11)	0.89 (0.56, 1.42)

↵*Crude OR from conditional logistic regression stratified by matching factors (age group and time of recruitment).
↵^†Adjusted OR additionally adjusted for family history of prostate cancer, participation in PSA testing, smoking status, and vigorous physical activity.