Table 1 Sociodemographic characteristics of the cases and controls
Characteristics | Controls (n = 226) | Cases (n = 113) | χ 2 | P | ORa | 95 % CIb (OR) | |
|---|---|---|---|---|---|---|---|
Maternal age (years), n (%) | Â | Â | 0.983 | 0.805 | Â | Â | Â |
 20–24 | 74 (32.7) | 43 (38.1) |  |  | 1 |  |  |
 25–29 | 96 (42.5) | 45 (39.8) |  |  | 0.807 | 0.481 | 1.352 |
 30–34 | 51 (22.6) | 23 (20.4) |  |  | 0.776 | 0.418 | 1.442 |
 ≥ 35 | 5 (2.2) | 2 (1.8) |  |  | 0.688 | 0.128 | 3.702 |
Maternal education level, n (%) | Â | Â | 6.460 | 0.033* | Â | Â | Â |
 Primary school and below | 10 (4.4) | 13 (11.5) |  |  | 1.650 | 0.760 | 3.582 |
 Middle school | 160 (70.8) | 79 (69.9) |  |  | 4.673 | 1.476 | 14.795 |
 College and above | 56 (24.8) | 21 (18.6) |  |  | 1 |  |  |
Maternal occupation, n (%) | Â | Â | 6.708 | 0.243 | Â | Â | Â |
 Farmer | 88 (38.9) | 39 (34.5) |  |  | 1.723 | 0.756 | 3.928 |
 Migrant worker | 18 (8.0) | 15 (13.3) |  |  | 3.241 | 1.189 | 8.836 |
 Business/company staff | 35 (15.5) | 9 (8.0) |  |  | 1 |  |  |
 Worker | 16 (7.1) | 9 (8.0) |  |  | 2.187 | 0.730 | 6.552 |
 Staff in administrative institutions | 22 (9.7) | 13 (11.5) |  |  | 2.298 | 0.843 | 6.267 |
 House wife or else | 47 (20.8) | 28 (24.8) |  |  | 2.317 | 0.971 | 5.526 |