TABLE 3.
Distribution of Select Characteristics Among Respondents and Nonrespondents in the Y6FU, Based on Information From the IFPSII
| Characteristic | Participants in the Y6FU (N = 1542), % | Nonparticipants in the Y6FU (N = 1416), % | χ2 Probability |
|---|---|---|---|
| Maternal characteristics | |||
| Age (y) | <.001 | ||
| 18–24 | 15.1 | 31.4 | |
| 25–34 | 65.1 | 58.5 | |
| 35–43 | 19.8 | 10.1 | |
| Marital status | <.001 | ||
| Married or cohabiting | 83.7 | 73.9 | |
| Other | 16.3 | 26.1 | |
| Education | <.001 | ||
| High school or less | 16.6 | 25.8 | |
| Some college | 37.2 | 43.4 | |
| College graduate | 46.2 | 30.8 | |
| Income (% of poverty threshold) | <.001 | ||
| <185% | 35.2 | 48.9 | |
| 185–<350% | 37.9 | 33.7 | |
| ≥350% | 26.9 | 17.4 | |
| Employment status (prenatal) | .30 | ||
| Employed | 67.0 | 65.2 | |
| Not employed | 33.0 | 34.8 | |
| Parity | .37 | ||
| 1 | 28.3 | 29.8 | |
| 2 | 42.2 | 39.6 | |
| ≥3 | 29.5 | 30.6 | |
| Race and ethnicity | <.01 | ||
| White | 86.6 | 81.8 | |
| Black | 3.7 | 6.1 | |
| Hispanic | 5.6 | 7.0 | |
| Other | 4.1 | 5.1 | |
| Region | <.001 | ||
| West | 19.7 | 20.6 | |
| Midwest | 31.1 | 28.7 | |
| South | 29.7 | 35.5 | |
| Northeast | 19.5 | 15.2 | |
| Prenatal smoking | <.001 | ||
| Yes | 7.4 | 12.2 | |
| No | 92.6 | 87.8 | |
| Prenatal care, initial visit (wk) | <.01 | ||
| <13 | 90.6 | 87.0 | |
| 13–24 | 6.1 | 7.9 | |
| ≥25 | 3.3 | 5.1 | |
| Returned to work when infant was ≤6 wk old | .29 | ||
| Yes | 14.3 | 16.0 | |
| No | 85.7 | 84.0 | |
| Prepregnancy BMI | .48 | ||
| Underweight (<18.5) | 4.3 | 5.2 | |
| Normal wt (18.5–24.9) | 44.7 | 45.7 | |
| Overweight (25.0–29.9) | 26.3 | 26.0 | |
| Obese (≥30.0) | 24.7 | 23.1 | |
| Number of postnatal questionnaires returned | <.001 | ||
| 1–7 | 25.5 | 53.2 | |
| 8–10 | 74.5 | 46.8 | |
| Infant characteristics | |||
| Gender | .60 | ||
| Male | 50.0 | 49.0 | |
| Female | 50.0 | 51.0 | |
| Breastfeeding initiation | .18 | ||
| Yes | 86.2 | 84.5 | |
| No | 13.8 | 15.5 | |
| Breastfeeding durationa (wk) | <.001 | ||
| <3 | 20.7 | 24.3 | |
| 3–17.1 | 19.5 | 25.7 | |
| ≥17.2 | 29.7 | 20.3 | |
| Breastfeeding at last questionnaire | 30.1 | 29.7 | |
| WIC participation | <.001 | ||
| Yes | 31.9 | 49.7 | |
| No | 68.1 | 50.3 | |
| Food allergy | .17 | ||
| Yes | 22.9 | 20.5 | |
| No | 77.1 | 79.5 | |
| Birth wt (lb) | .06 | ||
| <8 | 63.0 | 66.3 | |
| ≥8 | 37.0 | 33.7 | |
| Gestational age (wk) | .37 | ||
| <39 | 34.4 | 36.0 | |
| ≥39 | 65.6 | 64.0 |
WIC, Special Supplemental Nutrition Program for Women, Infants, and Children.
a
Breastfeeding duration was divided into categories by tertile among those with a value (ie, those that were not censored), and the censored cases formed a fourth category.