Table 4. The Joint Association of Maternal Levels of Folate and Vitamin B12 and Homocysteine With Congenital Heart Disease (CHD) Risk in Offspring.
| Maternal serum levels of vitamin B12 and homocysteine | Maternal serum levels of folate at early to midpregnancy | ||
|---|---|---|---|
| Low (Q1, <13.8 ng/mL) | Medium (Q2-Q3, 13.8-18.5 ng/mL) | High (Q4, >18.5 ng/mL) | |
| Vitamin B12 | |||
| Normala | |||
| CHD cases/controls, No. | 11/62 | 29/230 | 18/98 |
| aOR (95% CI) | 1.48 (0.67-3.29) | 1 [Reference] | 1.54 (0.78-3.10) |
| Deficiencyb | |||
| CHD cases/controls, No. | 40/46 | 15/54 | 16/26 |
| aOR (95% CI) | 7.30 (3.83-13.89) | 2.18 (1.06-4.52) | 6.51 (2.79-15.2) |
| Multiplicative interactionc | P = .14 | NA | P = .25 |
| Homocysteine | |||
| Normald | |||
| CHD case/controls, No. | 23/77 | 30/256 | 20/104 |
| aOR (95% CI) | 2.44 (1.3-4.56) | 1 [Reference] | 1.59 (0.84-3.01) |
| Elevatede | |||
| CHD case/controls, No. | 28/31 | 14/28 | 14/20 |
| aOR (95% CI) | 8.93 (4.33-18.44) | 3.92 (1.80-8.52) | 7.17 (2.98-17.27) |
| Multiplicative interactionc | P = .90 | NA | P = .82 |
Abbreviations: aOR, adjusted odds ratio; NA, not applicable; Q, quantile.
To convert homocysteine to μmol/L, multiply by 7.397; vitamin B12 to pmol/L, multiply by 0.7378.
Normal levels defined as 300 pg/mL and above.
Deficient levels defined as below 300 pg/mL.
We used multiplicative interaction analyses with adjustment for maternal 5,10-methylenetetrahydrofolate reductase (MTHFR) 677, MTHFR 1298, and 5-methyltetrahydrofolate-homocysteine methyltransferase reductase 66 polymorphisms, periconceptional folic acid supplementation, education, occupation, parity, abortion history, pregnancy with diabetes, pregnancy with hypertension, pregnancy with cardiac diseases, infection, and in vitro fertilization and embryo transfer.
Normal levels defined as below 0.95 mg/L.
Elevated levels defined as 0.95 mg/L and above.