Table 3

 Multivariate odds ratios (95% confidence intervals) for colorectal cancer by quintiles of folate after stratification by baseline and tumour characteristics

Plasma folate*Q1Q2Q3Q4Q5p Trend
*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.
All odds ratios were adjusted for body mass index, current smoking, recreational and occupational physical activity, and alcohol intake.
Case/referent frequencies: men Q1–5, 7/36, 24/36, 20/36, 23/36, 19/36, women Q1–5, 20/50, 26/51, 36/50, 28/51, 18/50; age ⩽59 years Q1–5, 12/31, 19/41, 24/37, 12/33, 19/37, age >59 years Q1–5, 15/55, 31/46, 32/49, 39/54, 18/49; cases with follow up between recruitment to the cohort and CRC diagnosis ⩽ median 4.2 years Q1–5, 16/39, 25/44, 29/41, 28/42, 12/51, cases with follow up >median 4.2 years Q1–5, 11/47, 25/43, 27/45, 23/45, 25/35; right sided colon cancer cases Q1–5, 9/30, 17/31, 13/23, 17/32, 14/23, left sided colon cancer cases Q1–5, 6/29, 16/32, 25/29, 14/24, 8/22; rectal cancer cases Q1–5, 12/27, 17/24, 18/34, 20/31, 15/41; Dukes’ stage A/B cases Q1–5, 14/48, 32/52, 31/47, 27/39, 15/46, Dukes’ stage C/D cases Q1–5, 13/37, 16/34, 25/38, 24/46, 21/40.
†Age 59 years was selected to approximate the median 59.8 years without dividing the study group in the middle of a large sampling cluster at 60 years.
Sex: men1.002.71 (0.97–7.53)1.81 (0.62–5.26)2.16 (0.74–6.35)1.78 (0.59–5.39)0.726
Sex: women1.001.17 (0.57–2.42)1.96 (0.94–4.09)1.50 (0.70–3.21)0.97 (0.42–2.17)0.698
Age ⩽ 59 y†1.001.26 (0.50–3.15)1.66 (0.66–4.18)1.07 (0.37–3.09)1.51 (0.54–4.25)0.590
Age >59 y†1.002.00 (0.95–4.23)2.41 (1.10–5.26)2.73 (1.27–5.87)1.24 (0.53–2.89)0.265
Follow up ⩽4.2 y1.001.47 (0.66–3.26)1.63 (0.69–3.83)1.70 (0.74–3.94)0.55 (0.21–1.44)0.401
Follow up >4.2 y1.002.15 (0.91–5.08)2.49 (1.04–6.00)2.64 (1.06–6.62)3.87 (1.52–9.87)0.007
Site: right colon1.001.44 (0.53–3.93)1.78 (0.56–5.63)2.33 (0.78–6.93)2.03 (0.67–6.14)0.126
Site: left colon1.001.87 (0.57–6.09)3.98 (1.19–13.26)2.31 (0.71–7.49)1.13 (0.27–4.77)0.586
Site: rectum1.001.13 (0.38–3.37)0.78 (0.26–2.26)0.99 (0.31–3.07)0.50 (0.15–1.55)0.178
Stage: Dukes’ A/B1.002.07 (0.94–4.57)2.26 (0.99–5.14)2.27 (0.96–5.35)1.16 (0.44–3.02)0.576
Stage: Dukes’ C/D1.001.14 (0.47–2.77)1.68 (0.72–3.91)1.34 (0.56–3.25)1.27 (0.54–3.01)0.586