Table 2

Relative risk of baseline folate intake and colon cancer according to LINE-1 methylation level among 88 691 women from the Nurses' Health Study (NHS) and 47 363 men from the Health Professionals Follow-up Study (HPFS)

Energy-adjusted folate intake (μg/day)Ptrend
<200200–299300–399≥400
All cancer cases
No. cases/person-years101/461 357166/756 398132/472 313210/873 018
Age-adjusted RR (95% CI)1.00.84 (0.66 to 1.08)0.91 (0.70 to 1.19)0.79 (0.62 to 1.00)0.07
Multivariate RR (95% CI)*1.00.80 (0.62 to 1.03)0.82 (0.62 to 1.09)0.76 (0.59 to 0.99)0.16
LINE-1 low (<55%) cancer cases
No. cases/person-years31/461 41634/756 51136/472 40647/873 179
Age-adjusted RR (95% CI)1.00.57 (0.35 to 0.92)0.83 (0.51 to 1.34)0.58 (0.37 to 0.92)0.05
Multivariate RR (95% CI)*1.00.54 (0.33 to 0.88)0.75 (0.46 to 1.23)0.57 (0.36 to 0.91)0.08
LINE-1 medium (55–64%) cancer cases
No. cases/person-years47/461 39977/756 47846/472 39495/873 124
Age-adjusted RR (95% CI)1.00.84 (0.58 to 1.21)0.68 (0.45 to 1.02)0.76 (0.53 to 1.08)0.21
Multivariate RR (95% CI)*1.00.80 (0.55 to 1.15)0.61 (0.40 to 0.93)0.74 (0.51 to 1.06)0.31
LINE-1 high (≥65%) cancer cases
No. cases/person-years23/461 42055/756 49450/472 38368/873 145
Age-adjusted RR (95% CI)1.01.23 (0.75 to 2.00)1.51 (0.92 to 2.48)1.11 (0.69 to 1.79)0.92
Multivariate RR (95% CI)*1.01.17 (0.72 to 1.90)1.36 (0.82 to 2.26)1.08 (0.66 to 1.75)0.94
  • * Multivariate models are adjusted for age (continuous), gender, energy intake (kcal), screening sigmoidoscopy or colonoscopy (yes/no), family history of colorectal cancer (yes/no), aspirin use (≥2 tablets/week or fewer), smoking (pack-years), physical activity in metabolic equivalents (METs) (quintiles), body mass index in five categories (<21, 21–22.9, 23–24.9, 25–29.9, 30+), colon polyps (yes/no), beef intake (quintiles), calcium intake (quintiles), multi-vitamin use (yes/no), alcohol use (none, <5, 5–14.9, ≥15 g/day), and intake of vitamin B6, B12, and methionine (quintiles).

  • LINE-1, long interspersed nucleotide element-1.