Table 1.
PROGRESS cohort characteristics
| Characteristic | N=456 |
|---|---|
| Child’s sex, n (% male) | 252 (55) |
| Prenatal ETS exposure, n (%) | 160 (35) |
| Maternal education at enrollment | |
| Less than high school, n (%) | 181 (40) |
| Some high school or high school graduate, n (%) | 170 (37) |
| More than high school, n (%) | 105 (23) |
| Socioeconomic status | |
| Low, n (%) | 235 (52) |
| Medium, n (%) | 171 (37) |
| High, n (%) | 50 (11) |
| Maternal age at enrollment years, median (25th–75th) | 28.0 (24.4–35.5) |
| Average prenatal PM2.5 µg/m3, median (25th–75th) | 23.1 (20.8–24.5) |
| Normalized relative cord mtDNA content, geometric mean (25th–75th) | 1.13 (1.00–1.32) |
a
Differences in categorical variables tested using Pearson Chi-Square, differences in continuous variables tested using Mann Whitney U test