Table 1.
Residential environmental characteristics of the study subjects
| Characteristics | Controls (N = 75) | Cases (N = 44) | p Value |
|---|---|---|---|
| n (%) or median (interquartile) | n (%) or median (interquartile) | ||
| Gestational weeks at the time of questionnaires (weeks) a | 24 (10) | 24 (4) | 0.998 |
| Gestational weeks at the time of field investigation (weeks) a | 26 (8) | 25 (3) | 0.398 |
| Time spent indoors each day during the first trimester (hours) a | 20 (5) | 18 (5) | 0.850 |
| House renovation and ventilation | |||
| No renovation | 54 (72.0) | 30 (68.27) | 0.002 |
| Living in a newly redecorated house with move-in interval < 3 months | 2 (2.7) | 9 (20.5) | |
| Living in a newly redecorated house with move-in interval ≥ 3 months | 19(25.3) | 5 (11.4) | |
| Indoor combustion sources | |||
| Electric cooking stoves | 12 (16.0) | 7(15.9) | 0.967 |
| Charcoal or wood burning | 0 | 0 | |
| Household piped gas burning | 63 (84.0) | 37 (84.1) | |
| Indoor floor decoration | |||
| Wood-base flooring | 35 (46.7) | 16 (36.4) | 0.389 |
| Marble and tile paving | 9 (12.0) | 10 (22.7) | |
| Carpet | 2 (2.7) | 2 (4.5) | |
| Mix of various materials | 29 (38.7) | 16 (36.4) | |
| Indoor wall decoration | |||
| Wallpaper | 4 (5.3) | 2 (4.5) | 0.934 |
| Paint | 35 (46.7) | 22 (50.0) | |
| Mix of various materials | 36 (48.0) | 20 (45.5) | |
| Indoor furniture and ornaments | |||
| Wood-base furniture | 37 (49.3) | 23 (52.3) | 0.452 |
| Wood and leather furniture | 13 (17.3) | 4 (9.1) | |
| Mix of various materials | 25 (33.3) | 17 (38.6) | |
| Second-hand smoke | |||
| Not exposed | 47 (62.7) | 21 (47.7) | 0.112 |
| Exposed | 28 (37.3) | 23 (52.3) | |
| Exposure to environmental pollutants nearby the residence | |||
| Cornfields and orchards | 2 | 4 | |
| Chemical plant | 1 | 0 | |
| Heavy-traffic road | 25 | 18 | |
| Incineration plant | 0 | 1 | |
| More than two facilities concomitantly | 0 | 4 | |
| Special facilities combined | |||
| No | 47 (62.7) | 17 (38.6) | 0.004 |
| Heavy traffic road | 25 (33.3) | 18 (40.9) | |
| Other special facilities | 3 (4.0) | 9 (20.5) | |
| Smoke ventilators usage when cooking | |||
| No | 14 (18.7) | 18 (40.9) | 0.008 |
| Yes | 61 (81.3) | 26 (59.1) | |
| Exposure to household chemical products | |||
| Pesticides | 7 | 2 | |
| Disinfectants and sanitizers | 1 | 1 | |
| Paints, dyes and glues | 1 | 0 | |
| Household cleaning agents | 5 | 2 | |
| Special chemicals combined | |||
| None | 52 (69.3) | 32 (72.7) | 0.917 |
| One | 14 (18.7) | 7 (15.9) | |
| Multiple | 9 (12.0) | 5 (11.4) | |
aFor abnormally distributed continuous variables, the median (interquartile) was used to describe the distribution, while the P values were calculated by the Mann–Whitney U-test