Characteristics of subjects and maternal folic acid supplementation, China, 1993–1995
| Characteristics | Folic acid users | Non-users | p-value |
| Subjects | 4542 | 4548 | |
| Age at child birth years | 24.8±2.5 | 25.9±3.5 | <0.001 |
| Only child | 4104 (90.5) | 3545 (78.0) | <0.001 |
| Education | |||
| Senior high school or more | 1025 (24.5) | 1214 (28.6) | <0.001 |
| Junior high school | 2325 (55.6) | 2012 (47.4) | |
| Primary school or less | 829 (19.8) | 1022 (24.1) | |
| Occupation | |||
| Farmer | 1579 (34.8) | 1585 (34.9) | 0.001 |
| Factory worker | 1771 (39.0) | 1615 (35.5) | |
| Other or unknown | 1192 (26.2) | 1348 (29.6) | |
| Sex of infant | |||
| Male | 2382 (52.4) | 2390 (52.6) | 0.919 |
| Female | 2160 (47.6) | 2158 (47.4) | |
Data are presented as n, mean±sd or n (%), unless otherwise stated. Values for some characteristics may not be equal to total numbers in each group because of missing values.