Table 1.
Characteristics of participants in the analytic sample and those excluded due to missing data, NICHD SECCYDa, 1991–2004.
| Characteristicsb | Analytic samplec n = 895 |
Excluded sampled n = 469 |
P valuee |
|---|---|---|---|
| Maternal characteristics | |||
| Education | 0.0001 | ||
| Less than a bachelor's degree | 550 (61.5) | 331 (70.7) | |
| Bachelor's degree or above | 345 (38.5) | 137 (29.3) | |
| Poverty | 0.412 | ||
| At or below poverty line | 99 (11.6) | 44 (13.3) | |
| Above poverty line | 757 (88.4) | 287 (86.7) | |
| Family structure | 0.703 | ||
| Living single | 121 (14.0) | 44 (13.2) | |
| Not living single | 742 (86.0) | 290 (86.8) | |
| Breastfeeding | < 0.0001 | ||
| Yes | 555 (62.0) | 222 (47.3) | |
| No | 340 (38.0) | 247 (52.7) | |
| Child characteristics | |||
| Birth weight (kg), mean ± SD | 3.50 ± 0.52 | 3.47 ± 0.50 | 0.312 |
| Sex | 0.007 | ||
| Female | 456 (51.0) | 203 (43.3) | |
| Male | 439 (49.0) | 266 (56.7) | |
| Race | 0.646 | ||
| White | 723 (80.8) | 374 (79.7) | |
| Nonwhite | 172 (19.2) | 95 (20.3) |
Abbreviation: SD, standard deviation.
NICHD SECCYD = National Institute of Child Health and Human Development Study of Early Child Care and Youth Development.
Poverty and family structure were assessed when child was 24 months. Other maternal and child characteristics were assessed when child was one month.
There were 39 missing data on poverty and 32 missing data on family structure.
There were 135 missing data on family structure, 138 missing data on poverty, and 1 missing data on education.
P value was from a Chi-squared (χ2) test or t-test. χ2 tests were used to determine significance for categorical variables (expressed in frequencies with percentage values and t-tests were used to determine the significance for continuous variables (expressed as mean ± SD).