Table 2. NVP distribution in case and control groups and the OR values between NVP and NTDs stratified by intake of folic acid supplements.
| Case | Control | Crude | Adjusted* | ||||
|---|---|---|---|---|---|---|---|
| Factor | n = 459 | n = 459 | P | OR (95%CI) | P | OR (95%CI) | P |
| NVP# | |||||||
| Light | 273 | 318 | 0.002 | 1.000 | 1.000 | ||
| Moderate | 133 | 113 | 1.469(1.063,2.031) | 0.020 | 1.626(1.117,2.366) | 0.011 | |
| Severe | 53 | 28 | 2.403(1.437,4.017) | <0.001 | 1.966(1.098,3.523) | 0.023 | |
| Intake of folic acid supplements# | |||||||
| Light NVP | 97 | 155 | 0.566 | 1.000 | 1.000 | ||
| Moderate NVP | 35 | 64 | 1.003(0.594,1.694) | 0.992 | 0.967(0.537,1.744) | 0.912 | |
| Severe NVP | 10 | 11 | 1.851(0.729,4.699) | 0.195 | 1.920(0.710,5.197) | 0.199 | |
| Non-intake of folic acid supplements# | |||||||
| Light NVP | 176 | 163 | <0.001 | 1.000 | 1.000 | ||
| Moderate NVP | 98 | 49 | 2.055(1.320,3.199) | 0.001 | 2.292(1.408,3.730) | 0.001 | |
| Severe NVP | 43 | 17 | 2.147(1.140,4.043) | 0.018 | 2.103(1.058,4.180) | 0.034 | |
*:Adjusted OR and 95%CI were calculated by adjusting for the potential confounders, including age, occupation, education, annual income, BMI, passive smoking, exposure to pesticide, chronic disease, use of folic acid supplements.
#: The conditional logistic regression model was used to calculate the parameters.