TABLE 3.
Risk of CRC during the postfortification period (1998–2016) according to postfortification and prefortification folate intakes1
| Cases, n | Baseline | Cumulative | Simple update (0–4 y lag) |
|---|---|---|---|
| 965 | 965 | 892 | |
| Postfortification folate intake | |||
| Total folate, per 400 DFE/d | 0.97 (0.91, 1.03) | 0.94 (0.88, 1.01) | 0.93 (0.88, 0.99) |
| Prefortification intake adjusted2 | 0.97 (0.92, 1.03) | 0.94 (0.88, 1.00) | 0.96 (0.90, 1.01) |
| Dietary folate per 400 DFE/d | 1.03 (0.87, 1.23) | 1.03 (0.86, 1.23) | 1.00 (0.86, 1.16) |
| Prefortification intake adjusted2 | 1.04 (0.87, 1.24) | 1.04 (0.86, 1.25) | 1.01 (0.87, 1.17) |
| Synthetic folic acid, per 400 DFE/d | 0.97 (0.91, 1.03) | 0.94 (0.88, 1.01) | 0.93 (0.88, 0.98) |
| Prefortification intake adjusted2 | 0.97 (0.91, 1.03) | 0.94 (0.87, 1.00) | 0.95 (0.90, 1.01) |
| Natural folate, per 400 DFE/d | 1.00 (0.70, 1.42) | 0.95 (0.64, 1.42) | 1.04 (0.70, 1.53) |
| Prefortification intake adjusted2 | 1.00 (0.70, 1.43) | 0.96 (0.64, 1.43) | 1.06 (0.71, 1.57) |
| Prefortification folate intake2 | |||
| Total folate, per 400 DFE/d | 0.82 (0.72, 0.93) | 0.82 (0.72, 0.93) | 0.81 (0.74, 0.90) |
| Post-fortification intake adjusted | 0.82 (0.72, 0.93)3 | 0.82 (0.72, 0.93)4 | 0.83 (0.75, 0.92)5 |
| Dietary folate, per 400 DFE/d | 0.96 (0.69, 1.34) | 0.96 (0.69, 1.34) | 0.90 (0.66, 1.23) |
| Postfortification intake adjusted | 0.94 (0.67, 1.33)3 | 0.95 (0.67, 1.33)4 | 0.90 (0.65, 1.24)5 |
| Synthetic folic acid per 400 DFE/d | 0.83 (0.77, 0.90) | 0.83 (0.77, 0.90) | 0.85 (0.78, 0.92) |
| Postfortification intake adjusted | 0.85 (0.78, 0.93)3 | 0.86 (0.79, 0.94)4 | 0.88 (0.81, 0.95)5 |
| Natural folate, per 400 DFE/d | 0.89 (0.52, 1.51) | 0.89 (0.52, 1.51) | 0.90 (0.55, 1.47) |
| Postfortification intake adjusted | 0.88 (0.52, 1.50)3 | 0.88 (0.52, 1.51)4 | 0.90 (0.55, 1.47)5 |
All values are HRs (95% CIs), stratified by age and calendar year and adjusted for family history of CRC, endoscopy, height, BMI, pack-y of smoking before age 30 y, physical activity, duration of regular aspirin or other NSAID use, duration of multivitamin use (for dietary folate and natural folate analysis), menopausal status and menopausal hormone use, alcohol intake, total energy, dietary fiber, total vitamin D (for total folate and synthetic folic acid analysis), dietary vitamin D (for dietary folate and natural folate analysis), total calcium (for total folate and synthetic folic acid analysis), dietary calcium (for dietary folate and natural folate analysis), red meat, and processed meat. DFE, dietary folate equivalent; NSAID, nonsteroidal anti-inflammatory drug.
Prefortification folate intake was calculated as the cumulative average of folate intake before 1998.
Baseline (1998) postfortification folate intake was adjusted.
Cumulative average postfortification folate intake was adjusted.
Simple updated postfortification folate intake was adjusted.