Table 2.
Intake of nutrients involved in folate-mediated one-carbon metabolism and time to diagnosis of endometrial cancer: overall associations and those stratified by time from baseline
| P trenda | Time from baseline |
P interactionb | ||||||
|---|---|---|---|---|---|---|---|---|
| Overall |
≤3 years non-cases: 4111 cases: 458 |
>3 years non-cases: 107 974 cases: 1871 |
||||||
| HR | 95% CI | HR | 95% CI | HR | 95% CI | |||
| Total folate (post-fortification) | 0.05 | 0.74 | ||||||
| Q1 | Reference | Reference | Reference | |||||
| Q2 | 1.09 | (0.96–1.25) | 0.95 | (0.74–1.22) | 1.13 | (0.98–1.31) | ||
| Q3 | 1.09 | (0.95–1.25) | 1.06 | (0.83–1.34) | 1.10 | (0.95–1.27) | ||
| Q4 | 1.10 | (0.96–1.26) | 1.12 | (0.88–1.42) | 1.09 | (0.94–1.27) | ||
| Q5 | 1.17 | (1.02–1.34) | 1.12 | (0.88–1.43) | 1.18 | (1.02–1.37) | ||
| Natural folate | 0.02 | 0.26 | ||||||
| Q1 | Reference | Reference | Reference | |||||
| Q2 | 1.22 | (1.06–1.40) | 0.99 | (0.77–1.28) | 1.28 | (1.11–1.48) | ||
| Q3 | 1.18 | (1.03–1.35) | 1.15 | (0.91–1.47) | 1.19 | (1.02–1.37) | ||
| Q4 | 1.20 | (1.05–1.38) | 1.06 | (0.83–1.36) | 1.24 | (1.07–1.44) | ||
| Q5 | 1.23 | (1.07–1.42) | 1.27 | (1.00–1.62) | 1.22 | (1.05–1.41) | ||
| Synthetic folate (folic acid) | 0.98 | 0.74 | ||||||
| Q1 | Reference | Reference | Reference | |||||
| Q2 | 1.13 | (0.99–1.29) | 1.08 | (0.85–1.37) | 1.14 | (0.99–1.32) | ||
| Q3 | 1.10 | (0.96–1.26) | 1.15 | (0.91–1.45) | 1.09 | (0.94–1.25) | ||
| Q4 | 1.06 | (0.92–1.22) | 0.95 | (0.74–1.22) | 1.09 | (0.94–1.26) | ||
| Q5 | 1.04 | (0.90–1.20) | 1.10 | (0.86–1.40) | 1.03 | (0.88–1.19) | ||
| Pre-fortification total folatec | 0.04 | 0.97 | ||||||
| Q1 | Reference | Reference | Reference | |||||
| Q2 | 1.06 | (0.92–1.21) | 1.00 | (0.78–1.28) | 1.07 | (0.93–1.24) | ||
| Q3 | 1.11 | (0.97–1.28) | 1.06 | (0.93–1.35) | 1.13 | (0.98–1.30) | ||
| Q4 | 1.14 | (0.99–1.31) | 1.11 | (0.87–1.41) | 1.15 | (0.99–1.33) | ||
| Q5 | 1.13 | (0.99–1.30) | 1.14 | (0.89–1.45) | 1.13 | (0.98–1.32) | ||
| Vitamin B2 | 0.04 | 0.08 | ||||||
| Q1 | Reference | Reference | Reference | |||||
| Q2 | 1.04 | (0.90–1.20) | 0.74 | (0.56–0.98) | 1.12 | (0.96–1.29) | ||
| Q3 | 1.10 | (0.96–1.26) | 1.06 | (0.83–1.34) | 1.11 | (0.96–1.29) | ||
| Q4 | 1.11 | (0.97–1.27) | 1.10 | (0.87–1.39) | 1.11 | (0.96–1.29) | ||
| Q5 | 1.14 | (0.99–1.31) | 1.11 | (0.88–1.41) | 1.15 | (0.99–1.33) | ||
| Vitamin B3 | 0.04 | 0.01 | ||||||
| Q1 | Reference | Reference | Reference | |||||
| Q2 | 1.09 | (0.95–1.24) | 0.82 | (0.63–1.06) | 1.16 | (1.01–1.33) | ||
| Q3 | 1.03 | (0.90–1.18) | 1.20 | (0.96–1.49) | 0.99 | (0.86–1.15) | ||
| Q4 | 0.97 | (0.85–1.11) | 0.83 | (0.64–1.07) | 1.01 | (0.88–1.17) | ||
| Q5 | 0.90 | (0.78–1.04) | 0.83 | (0.64–1.07) | 0.92 | (0.79–1.07) | ||
| Vitamin B6 | 0.01 | 0.04 | ||||||
| Q1 | Reference | Reference | Reference | |||||
| Q2 | 1.09 | (0.95–1.25) | 0.84 | (0.64–1.10) | 1.16 | (1.00–1.34) | ||
| Q3 | 1.13 | (0.99–1.30) | 1.25 | (0.99–1.57) | 1.10 | (0.95–1.28) | ||
| Q4 | 1.10 | (0.96–1.27) | 0.99 | (0.77–1.28) | 1.13 | (0.97–1.31) | ||
| Q5 | 1.24 | (1.08–1.42) | 1.38 | (1.10–1.73) | 1.20 | (1.03–1.39) | ||
| Vitamin B12 | 0.01 | 0.05 | ||||||
| Q1 | Reference | Reference | Reference | |||||
| Q2 | 1.04 | (0.90–1.19) | 0.80 | (0.61–1.06) | 1.10 | (0.95–1.28) | ||
| Q3 | 1.03 | (0.89–1.18) | 1.13 | (0.89–1.43) | 1.00 | (0.86–1.16) | ||
| Q4 | 1.14 | (0.99–1.30) | 0.99 | (0.77–1.26) | 1.18 | (1.02–1.36) | ||
| Q5 | 1.17 | (1.03–1.35) | 1.04 | (0.82–1.32) | 1.21 | (1.05–1.40) | ||
| Methionine | 0.23 | 0.35 | ||||||
| Q1 | Reference | Reference | Reference | |||||
| Q2 | 1.02 | (0.88–1.17) | 0.90 | (0.69–1.17) | 1.05 | (0.90–1.22) | ||
| Q3 | 1.07 | (0.93–1.22) | 1.07 | (0.84–1.36) | 1.06 | (0.92–1.23) | ||
| Q4 | 1.04 | (0.91–1.19) | 1.12 | (0.88–1.41) | 1.02 | (0.88–1.18) | ||
| Q5 | 1.09 | (0.95–1.24) | 0.93 | (0.73–1.19) | 1.13 | (0.98–1.30) | ||
HR, hazard ratio; CI, confidence interval; Q1–Q5, calorie-adjusted quintiles of intake for each nutrient (supplements not included); Q1 serves as the reference in all models.
All models adjusted for: age, race, body mass index, smoking status, oral-contraceptive use, menopausal hormone therapy use, caloric intake.
P trend calculated by treating each quintile variable as a continuous exposure.
P interaction from likelihood ratio tests comparing models with and without interaction terms for time from baseline and each dietary-intake exposure.
Total dietary folate intake using estimates of food nutritional content before US fortification (1996–98).