Table A1.
Summary Statistics for All Predictors.
| Variables | Frequency | Percent |
|---|---|---|
| Maternal education | ||
| No schooling | 2.25 | 22.07 |
| Primary school | 2870 | 24.13 |
| Middle school | 3968 | 33.36 |
| High school | 1349 | 11.34 |
| College | 1083 | 9.10 |
| Gender | ||
| Male | 6322 | 53.15 |
| Female | 5573 | 46.85 |
| Birth cohort | ||
| 1995–1999 | 2689 | 22.61 |
| 2000–2004 | 2509 | 21.09 |
| 2005–2009 | 3033 | 25.50 |
| 2010–2016 | 3664 | 30.80 |
| Minority status | ||
| Han | 10,490 | 88.19 |
| Minority | 1405 | 11.81 |
| Birth weight | ||
| Normal weight | 10,154 | 85.36 |
| Low birth weight | 628 | 5.28 |
| Unknown | 1113 | 9.36 |
| Gestational age | ||
| <37 weeks | 11,433 | 96.12 |
| ≥37 weeks | 462 | 3.88 |
| Hukou before age 3 | ||
| Rural | 9654 | 81.16 |
| Urban | 2241 | 18.84 |
| Maternal age at birth | ||
| <20 | 409 | 3.44 |
| 20–24 | 4400 | 36.99 |
| 24–29 | 4441 | 37.34 |
| 30–34 | 1873 | 15.75 |
| 35+ | 772 | 6.49 |
| Survey Year | ||
| 2010 | 8165 | 68.64 |
| 2012 | 1426 | 11.99 |
| 2014 | 1262 | 10.61 |
| 2016 | 1042 | 8.76 |
| N | 11,895 |
Notes. The descriptive results are un-weighted.