Background
Methods
Subjects
Data collection
Measurements of variables
Quality control
Statistical analysis
Results
Sociodemographic characteristics of the subjects
Characteristics | Controls (n = 226) | Cases (n = 113) |
χ
2
|
P
| ORa
| 95 % CIb (OR) | |
---|---|---|---|---|---|---|---|
Maternal age (years), n (%) | 0.983 | 0.805 | |||||
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 (%) | 6.460 | 0.033* | |||||
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 (%) | 6.708 | 0.243 | |||||
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 |
Screening of the predictors
Screened factors | Controls (n = 226) | Cases (n = 113) |
b
c
|
P
| ORa
| 95 % CIb (OR) | |
---|---|---|---|---|---|---|---|
Education level, n (%) | 0.031* | ||||||
College and above | 56 (24.8) | 21 (18.6) | 1 | ||||
Middle school | 160 (70.8) | 79 (69.9) | 0.500 | 0.206 | 1.650 | 0.760 | 3.582 |
Primary school and below | 10 (4.4) | 13 (11.5) | 1.542 | 0.009* | 4.673 | 1.476 | 14.795 |
Family income (Yuan/year/person), n (%) | 0.003* | ||||||
> 15,000 | 22 (9.7) | 6 (5.3) | 1 | ||||
10,001–15,000 | 10 (4.4) | 1 (0.9) | −1.003 | 0.381 | 0.367 | 0.039 | 3.462 |
5001–10,000 | 107 (47.3) | 39 (34.5) | 0.290 | 0.056 | 1.336 | 0.504 | 3.541 |
≤ 5000 | 87 (38.5) | 67 (59.3) | 1.038 | 0.034* | 2.824 | 1.084 | 7.355 |
Premarital medical examination, n (%) | 56 (24.8) | 13 (11.5) | −0.930 | 0.005* | 0.395 | 0.206 | 0.757 |
Upper respiratory tract infection, n (%) | 75 (33.2) | 55 (48.7) | 0.647 | 0.006* | 1.909 | 1.204 | 3.028 |
Complications of pregnancy, n (%) | 6 (2.7) | 9 (8.0) | 1.155 | 0.033* | 3.173 | 1.100 | 9.149 |
Contraceptive intake before pregnancy, n (%) | 2 (0.9) | 6 (5.3) | 1.837 | 0.026* | 6.280 | 1.247 | 31.634 |
Maternal occupational hazards exposure, n (%) | 5 (2.2) | 16 (14.2) | 1.987 | 0.000* | 7.291 | 2.597 | 20.466 |
Housing renovation, n (%) | 11 (4.9) | 21 (18.6) | 1.495 | 0.000* | 4.461 | 2.067 | 9.629 |
Fish/shrimp/meat/eggs intake, n (%) | 0.033* | ||||||
≤ 2 times/week | 16 (7.1) | 15 (13.3) | 1 | ||||
3~5 times/week | 79 (35.0) | 48 (42.5) | −0.434 | 0.282 | 0.648 | 0.294 | 1.429 |
> 5 times/week | 131 (58.0) | 50 (44.2) | −0.899 | 0.023* | 0.407 | 0.187 | 0.885 |
Milk/soymilk intake, n (%) | 0.000* | ||||||
≤ 2 times/week | 26 (11.5) | 35 (31.0) | 1 | ||||
3~5 times/week | 82 (36.3) | 36 (31.9) | −1.120 | 0.001* | 0.326 | 0.172 | 0.619 |
> 5 times/week | 118 (52.2) | 42 (37.2) | −1.330 | 0.000* | 0.143 | 0.143 | 0.490 |
Paternal occupational hazards exposure, n (%) | 3 (1.3) | 14 (12.4) | 2.352 | 0.000* | 10.512 | 2.954 | 37.402 |
Paternal strong tea drinking, n (%) | 20 (8.8) | 20 (17.7) | 0.795 | 0.019* | 2.215 | 1.138 | 4.313 |
Family history of NSCL/P, n (%) | 2 (0.9) | 13 (11.5) | 6.678 | 0.000* | 14.560 | 3.225 | 65.728 |
Establishment of the prediction model
Prediction of the discriminant analysis predictive effect
Accuracy of prediction
Actual classification | Predicted group membership | Total | |
---|---|---|---|
Control (%) | Case (%) | ||
Control | 200 (88.5) | 26 (11.5) | 226 |
Case | 29 (25.7) | 84 (74.3) | 113 |
Total | 229 | 110 | 339 |