Table 1.
Epidemiologic characteristics of NTD and control groups
| Characteristics | NTDs n (%a) | Control n (%a) | P c |
|---|---|---|---|
| 121b | 146b | ||
| Mother’s age (years) | 121 | 145 | 0.131 |
| <20 | 11 (9.1) | 14 (9.7) | |
| 20–24 | 45 (37.2) | 37 (25.5) | |
| 25–29 | 42 (34.7) | 52 (35.9) | |
| ≥30 | 23 (19.0) | 42 (29.0) | |
| Mother’s education | 114 | 141 | 0.792 |
| ≥High school graduation | 18 (15.8) | 24 (17.0) | |
| Gravidity (n) | 114 | 141 | 0.086 |
| 1 | 54 (47.4) | 50 (35.5) | |
| 2 | 41 (36.0) | 54 (38.3) | |
| ≥3 | 19 (16.7) | 37 (26.2) | |
| Periconceptional folic acid used | 121 | 146 | 0.570 |
| Yes | 7 (5.8) | 11 (7.5) | |
| Gestational age (weeks) | 90 | 120 | <0.001 |
| <18 | 20 (22.2) | 35 (29.2) | |
| 18–24 | 44 (48.9) | 79 (65.8) | |
| >24 | 26 (28.9) | 6 (5.0) | |
| Fetus sex | 121 | 144 | 0.937 |
| Male | 49 (40.5) | 59 (41.0) |
aPercentages may not equal 100 because of rounding
bNumber of subjects
cχ2 test was used to calculate P values
dPericonceptional refers to the month before conception and the first 3 months after conception