Table 2.
PM2.5 and NDVI exposure distribution between cases and controls per pregnancy period.
| Characteristic | Controls, N = 5,245a | Cases, N = 1,272a | p-valueb | ||
|---|---|---|---|---|---|
| Mean (SD) | (Min, Max) | Mean (SD) | (Min, Max) | ||
| Mean NDVI exposure | |||||
| 1st trimester | 0.36(0.20) | (0.00, 0.85) | 0.37(0.20) | (0.00, 0.83) | 0.12 |
| 2nd trimester | 0.37(0.18) | (0.00, 0.82) | 0.37(0.19) | (0.00, 0.80) | 0.70 |
| 3rd trimester | 0.38(0.20) | (0.00, 0.85) | 0.38(0.20) | (0.00, 0.80) | 0.40 |
| Full pregnancy | 0.37(0.08) | (0.06, 0.65) | 0.37(0.08) | (0.09, 0.60) | 0.68 |
| Mean PM2.5 exposure | |||||
| 1st trimester | 8.71(2.01) | (3.95, 17.27) | 8.63(2.00) | (3.90, 17.47) | 0.12 |
| 2nd trimester | 8.62(1.94) | (3.66, 17.11) | 8.54(1.85) | (4.15, 16.62) | 0.40 |
| 3rd trimester | 8.58(1.97) | (3.81, 17.31) | 8.61(1.97) | (4.08, 16.45) | 0.60 |
| Full pregnancy | 8.63(1.48) | (4.43, 13.23) | 8.58(1.44) | (4.76, 13.11) | 0.27 |
Abbreviation: PM2.5: Particulate matter <2.5 mg/m3; NDVI: Normalized Difference Vegetation Index.
a
Mean (SD), (Min, Max); Frequency (percentage).
b
Pearson’s Chi-squared test; Fisher’s exact test; Wilcoxon rank sum test. 1st Trimester included 1st, 2nd and 3rd month of a pregnancy; 2nd Trimester included 4th, 5th and 6th month of a pregnancy; 3rd Trimester included 7th, 8th, 9th month of a pregnancy. Bold values indicated P-value less than 0.05.