Table 2 Odds ratios for colorectal cancer by categories of plasma folate and homocysteine.

Folate quintiles*	Q1	Q2	Q3	Q4	Q5	p Trend
Cases/referents	27/86	50/87	56/86	51/87	37/86
Unadjusted OR (CI)	1.00	1.85 (1.07–3.19)	2.26 (1.29–3.95)	1.97 (1.12–3.47)	1.55 (0.85–2.85)	0.173
Adjusted OR† (CI)	1.00	1.72 (0.99–3.03)	2.00 (1.13–3.56)	1.87 (1.04–3.36)	1.34 (0.72–2.50)	0.325
Folate categories‡	<5 nmol/l	5–8 nmol/l	8–12 nmol/l	12–15 nmol/l	⩾15 nmol/l	p Trend
Cases/referents	20/60	86/162	76/121	22/37	17/52
Unadjusted OR (CI)	1.00	1.54 (0.88–2.70)	1.86 (1.04–3.32)	1.88 (0.89–3.96)	1.10 (0.52–2.32)	0.597
Adjusted OR† (CI)	1.00	1.52 (0.85–2.70)	1.81 (0.99–3.29)	1.71 (0.79–3.69)	1.01 (0.47–2.19)	0.734
Hcys quintiles§	Q1	Q2	Q3	Q4	Q5	p Trend
Cases/referents	39/86	37/88	54/88	52/88	44/86
Unadjusted OR (CI)	1.00	0.93 (0.54–1.56)	1.33 (0.80–2.21)	1.30 (0.77–2.19)	1.12 (0.65–1.95)	0.376
Adjusted OR† (CI)	1.00	0.87 (0.50–1.49)	1.26 (0.75–2.11)	1.27 (0.74–2.17)	1.12 (0.63–1.99)	0.354

OR, odds ratio; CI, 95% confidence interval; Hcys, homocysteine.

*Folate quintile cut offs were for men: 5.1, 6.7, 8.1, and 11.3; and for women: 5.7, 7.4, 9.4, and 13.0 nmol/l.

†Adjusted for body mass index, current smoking, recreational and occupational physical activity, and alcohol intake (alcohol data were available for approximately two thirds of subjects).

‡Categories selected to explore a greater range of plasma folate concentrations.

§Homocysteine quintile cut offs were for men: 9.7, 10.9, 12.4, and 15.1; and for women: 8.8, 10.3, 12.0, and 14.1 μmol/l.