Table 1.
Comparison of sample characteristics between matched pair cases and controls.
| Characteristics | Cases (n=55) | Controls (n=55) | p-value† |
|---|---|---|---|
| Parental Characteristics | |||
| Mother’s Age at Delivery (Years) | 24.5 | 22.3 | 0.031 |
| Father’s Age at Delivery (Years) | 32.4 | 31.5 | 0.432 |
| Periconceptional Folic Acid Use (# Yes) | 27 | 39 | 0.038¶ |
| Periconceptional Vitamin Use (# Yes) | 21 | 27 | 0.327¶ |
| Mother’s Betel Nut Use during Pregnancy (# Yes) | 6 | 1 | 0.131¶ |
| Any Medication Use during Pregnancy (# Yes) | 26 | 32 | 0.361¶ |
| Place of Birth (# Yes) | 0.161¶ | ||
| Home | 27 | 21 | |
| Birth center | 15 | 11 | |
| Hospital | 13 | 23 | |
| Reported Ultrasound During Pregnancy (# Yes) | 46 | 50 | 0.387¶ |
| Plasma Folate (ng/mL) | 4.7 | 4.7 | 0.918†† |
| Maternal MTHFR677 / MTHFR1298 variants‡ | § | ||
| CC / AA | 17 | 15 | |
| CT / AA | 6 | 5 | |
| TT / AA | 0 | 1 | |
| CC / AC | 11 | 23 | |
| CT / AC | 4 | 6 | |
| CC/ CC | 15 | 5 | |
| Water Arsenic Concentrations (μg/L) | 20.5 | 49.4 | 0.047†† |
| Toenail Arsenic Concentrations (μg/g) | 1.0 | 2.1 | 0.002†† |
| Infant Characteristics | |||
| Birth weight (kg) | 2.6 | 2.8 | 0.053 |
| Age at Enrollment (days) | 175 | 240 | 0.426‡‡ |
| Female (# Yes) | 23 | 23 | 0.999¶ |
| First Born (# Yes) | 23 | 25 | 0.823¶ |
| Toenail Arsenic Concentrations (μg/g) | 0.58 | 0.75 | 0.321 |
Reported p-value for comparison between cases and controls using a paired t-test unless indicated differently.
MTHFR variants only available for 53 of 55 cases.
Insufficient counts in multiple cells to conduct the McNemar test. Further reducing the number of categories to 4 [(1)677CC 1298AA, (2) 677CC 1298AC + 677CC 1298CC, (3) 677CT 1298 AA + 677TT + 1298 AA, (4) 677CT 1298AC] did not result in sufficient counts in cells for the McNemar test.
McNemar’s Chi-squared test used for comparison.
Wilcoxon Signed Rank test used for comparison.
Indicated p-value is for a paired t-test against the alternative of 60 days difference to test if the ± 2 month age at enrollment criteria was followed in the study.