Associations between dietary folate intake and lung cancer risk stratified by selected variables in former smokers
| Odds ratio (95% confidence interval)a for folate intake by quartileb | Trend test | |||||||
|---|---|---|---|---|---|---|---|---|
| Lowest quartile (<25 percentile) | 25–50 percentile | 50–75 percentile | Highest Quartile (>75 percentile) | |||||
| Total (case = 470/control = 472) | 1.00 | 1.02 (0.71–1.47) | 0.67 (0.46–0.99) | 0.53 (0.35–0.80) | <0.001 | |||
| Alcohol drinker | ||||||||
| No (220/175) | 1.00 | 0.73 (0.41–1.30) | 0.58 (0.31–1.05) | 0.69 (0.36–1.30) | 0.161 | |||
| Yes (250/297) | 1.00 | 1.32 (0.81–2.12) | 0.80 (0.48–1.33) | 0.48 (0.28–0.82) | 0.002 | |||
| Pack-years smoked | ||||||||
| <36 (191/242) | 1.00 | 1.08 (0.62–1.87) | 1.13 (0.64–1.99) | 0.89 (0.49–1.61) | 0.749 | |||
| ≥36 (279/230) | 1.00 | 1.02 (0.61–1.68) | 0.45 (0.26–0.78) | 0.34 (0.19–0.61) | <0.001 | |||
| Supplement folate intake | ||||||||
| No (205/211) | 1.00 | 0.74 (0.44–1.25) | 0.52 (0.29–0.95) | 0.33 (0.17–0.63) | 0.001 | |||
| Yes (265/261) | 1.00 | 1.41 (0.84–2.37) | 0.86 (0.51–1.46) | 0.78 (0.45–1.34) | 0.130 | |||
| Family lung cancer history | ||||||||
| No (369/411) | 1.00 | 1.12 (0.76–1.67) | 0.89 (0.58–1.35) | 0.60 (0.38–0.94) | 0.016 | |||
| Yes (101/61) | 1.00 | 0.57 (0.19–1.69) | 0.16 (0.05–0.48) | 0.27 (0.09–0.85) | 0.006 | |||
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 Quartile cutpoints were based on residual energy-adjusted intake among controls.