Table 1.
Selected characteristics of mothers and infants in the New Hampshire Birth Cohort sub-study reported here (n=356).
| Population Characteristic | Mean (range) or n (%)a |
|---|---|
| Maternal variables | |
| Maternal age, years | 31.5 (18.6–44.5) |
| <20 | 4 (1%) |
| 20–29 | 104 (29%) |
| 30–35 | 176 (49%) |
| >35 | 72 (20%) |
| Maternal education | |
| <11th grade | 3 (1%) |
| High school graduate / GED | 29 (8%) |
| Junior college, some college, technical school | 70 (20%) |
| College graduate | 135 (39%) |
| Postgraduate schooling | 106 (31%) |
| Relationship status | |
| Single | 37 (11%) |
| Married | 292 (85%) |
| Separated or divorced | 14 (4%) |
| Infant variables | |
| Infant Sex | |
| Male | 161 (45%) |
| Female | 195 (55%) |
| Infant Race | |
| White | 337 (100%) |
| Other | 0 (0%) |
| Attended day care | |
| 4 months of age | 118 (33%) |
| 8 months of age | 135 (38%) |
| 12 months of age | 147 (41%) |
| Household Tap Water [As] | 0.48b (<0.01–80) |
| <1 μg/L | 205 (58%) |
| 1–10 μg/L | 101 (28%) |
| >10 μg/L | 50 (14%) |
a
Sum of subjects for the following variables are less than the total sample size (n missing): maternal education (13), relationship status (13) and infant race (19).
b
Median concentration and range is reported, as data are log-normally distributed.