Table 3

Associations between dietary folate intake and lung cancer risk in former smokers

VariablesCases (n = 470)Controls (n = 472)Odds ratio (95% confidence interval)aP
No.%No.%
Food folate (μg/1000kcal/day)
 By median
  <130.428360.223650.01.000.002
  ≥130.418739.823650.00.60 (0.45–0.79)
 By quartile
  <103.513628.911825.01.00<0.001
  103.5–130.414731.311825.01.02 (0.71–1.47)
  130.4–162.710221.711825.00.67 (0.46–0.99)
  ≥ 162.78518.111825.00.53 (0.35–0.80)
Fortified folic acidb
 By median
  <52.615448.415949.81.000.721
  ≥52.616451.616050.21.11 (0.79–1.54)
 By quartile
  <37.58125.57924.81.000.544
  37.5–52.67323.08025.10.92 (0.58–1.45)
  52.6–72.77122.38125.30.86 (0.54–1.38)
  ≥72.79329.27924.81.27 (0.81–2.00)
Supplemental folic acid
  No (= 0)20543.621144.71.000.737
  Yes (> 0)26556.426155.31.06 (0.81–1.39)
 By tertile
  none20543.621144.71.000.406
  1–172.011825.113127.80.93 (0.66–1.32)
  ≥172.014731.313027.51.21 (0.85–1.70)
  • a Odds ratio (95% confidence interval) obtained from logistic regression model with adjustment for age, sex, ethnicity, total energy intake, body mass index, family-history of lung cancer, pack-year smoked, and alcohol consumption.

  • b Only for the subjects recruited since January, 1998 (cases = 318; controls = 319).