Table 2. Association between folic acid supplementation and GDM in pregnant women in Beijing, China, 2017–2021.
| FA supplementation | Total | GDM | Crude OR (95% CI)* | Adjusted OR (95% CI) † |
| Abbreviation: FA=Folic acid; GDM=gestational diabetes mellitus; OR=odds ratio; CI=confidence interval; FAO=folic acid only; MMFA=multiple micronutrients containing folic acid. * crude OR: logistic regression. No confounders were adjusted. † adjusted OR: logistic regression. Adjusted for maternal age, pre-pregnancy BMI, occupation, education, parity, smoking, and consumption of eggs, milk, vegetables, and fruits. “–” means data not available. | ||||
| Total | 3,421 | 643 (18.8) | − | − |
| FA supplementation | ||||
| No | 109 | 15 (13.8) | Reference | Reference |
| Yes | 3,312 | 628 (19.0) | 1.47 (0.84–2.55) | 1.52 (0.80–2.87) |
| Type | ||||
| FAO | 880 | 145 (16.5) | Reference | Reference |
| MMFA | 2,432 | 483 (19.9) | 1.26 (1.02–1.54) | 1.34 (1.05–1.72) |
| Nonusers | 109 | 15 (13.8) | 0.81 (0.46–1.44) | 0.76 (0.37–1.55) |
| Initial time | ||||
| Nonusers | 109 | 15 (13.8) | Reference | Reference |
| Before conception | 1,689 | 317 (18.8) | 1.45 (0.83–2.53) | 1.60 (0.80–3.22) |
| After conception | 1,623 | 311 (19.2) | 1.49 (0.85–2.60) | 1.64 (0.82–3.30) |
| Supplement frequency | ||||
| Nonusers | 109 | 15 (13.8) | Reference | Reference |
| ≤24 capsules per month | 675 | 141 (20.9) | 1.66 (0.93–2.94) | 1.82 (0.89–3.72) |
| >24 capsules per month | 2,557 | 472 (18.5) | 1.42 (0.82–2.47) | 1.55 (0.77–3.10) |
| Stratified by types | ||||
| Initial time | ||||
| FAO | ||||
| Nonusers | 109 | 15 (13.8) | Reference | Reference |
| Before conception | 465 | 69 (14.8) | 1.09 (0.60–1.99) | 1.36 (0.72–2.59) |
| After conception | 415 | 76 (18.3) | 1.41 (0.77–2.56) | 1.60 (0.85–3.00) |
| MMFA | ||||
| Nonusers | 109 | 15 (13.8) | Reference | Reference |
| Before conception | 1,224 | 248 (20.3) | 1.59 (0.91–2.80) | 1.78 (0.88–3.60) |
| After conception | 1,208 | 235 (19.5) | 1.51 (0.86–2.66) | 1.68 (0.83–3.39) |
| Supplement frequency | ||||
| FAO | ||||
| Nonusers | 109 | 15 (13.8) | Reference | Reference |
| ≤24 capsules per month | 190 | 37 (19.5) | 1.52 (0.79–2.91) | 1.87 (0.81–4.31) |
| >24 capsules per month | 658 | 105 (16.0) | 1.19 (0.66–2.13) | 1.48 (0.68–3.21) |
| MMFA | ||||
| Nonusers | 109 | 15 (13.8) | Reference | Reference |
| ≤24 capsules per month | 485 | 104 (21.4) | 1.71 (0.95–3.08) | 1.88 (0.91–3.90) |
| >24 capsules per month | 1,899 | 367 (19.3) | 1.50 (0.86–2.62) | 1.65 (0.82–3.32) |