Variable | tLBW Case | Control | \({{\varvec{\chi}}}^{2}\) a | P |
---|---|---|---|---|
N(%) | N(%) | |||
Socio-demographic characteristics | ||||
 Maternal age | ||||
  < 28 | 97(54.19) | 122(59.80) |  |  |
  ≥ 28 | 82(45.81) | 82(40.20) | 1.237 | 0.268 |
 Infant sex | ||||
  Female | 95(53.07) | 98(48.04) |  |  |
  Male | 84(46.93) | 106(51.96) | 0.996 | 0.326 |
 Parity | ||||
  1 | 83(46.37) | 103(50.49) |  |  |
  ≥ 2 | 96(53.63) | 101(49.51) | 0.648 | 0.421 |
 Maternal BMI (kg/m2) | ||||
  < 18.5 | 8(4.47) | 10(4.90) |  |  |
  18.5 ~ 24 | 111(62.01) | 131(64.22) |  |  |
  ≥ 24 | 60(33.52) | 63(30.88) | 0.318 | 0.853 |
 Village income per capita (RMB/year) | ||||
  < 6527b | 92(51.40) | 98(48.04) |  |  |
  ≥ 6527 | 87(48.60) | 106(51.96) | 0.430 | 0.512 |
 Individual SES index | ||||
  High | 74 (41.34) | 117(57.35) |  |  |
  Low | 105(58.66) | 87(42.35) | 7.778 | 0.002 |
 Maternal occupation | ||||
  Others | 41(22.91) | 59(28.92) |  |  |
  Famers or unemployed | 138(77.09) | 145(71.08) | 1.789 | 0.181 |
 Maternal education | ||||
  High schools or higher | 27(15.08) | 36(17.65) |  |  |
  Middle schools or lower | 152(84.92) | 168(82.35) | 0.456 | 0.500 |
 Paternal education | ||||
  High schools or higher | 37(20.67) | 35(17.16) |  |  |
  Middle schools or lower | 142(79.33) | 169(82.64) | 0.771 | 0.380 |
 Household income (Thousand RMB/year) | ||||
  Medium (Min ~ Max) | 15 (2 ~ 100) | 20 (2 ~ 150) | 6.334 | 0.012 |
Environmental exposure and lifestyles during pregnancy | ||||
 Household chemical fertilizer application | ||||
  None | 90(50.28) | 126(61.76) |  |  |
  Yes | 89(49.72) | 78(38.24) | 5.115 | 0.024 |
 Village chemical fertilizer application | ||||
  Low | 72(43.11) | 106(56.68) |  |  |
  High | 95(56.89) | 81(43.32) | 6.499 | 0.011 |
 Household pesticide application | ||||
  No | 173(96.65) | 200(98.04) |  |  |
  Yes | 6(3.35) | 4(1.96) |  | 0.525c |
 Maternal personal contact with pesticides | ||||
  No | 157(99.37) | 195(97.50) |  |  |
  Yes | 1(0.63) | 5(2.50) |  | 0.234c |
 Living distance from highway (m) | ||||
  ≤ 1000 | 45(25.41) | 64(31.37) |  |  |
  > 1000 | 134(74.86) | 140(68.63) | 1.819 | 0.177 |
 IAPCC | ||||
  0 | 80(44.69) | 111(54.41) |  |  |
  ≥ 1 | 99(55.31) | 93(45.59) | 3.602 | 0.058 |
 Maternal active smoking | ||||
  No | 177(100.00) | 197(98.99) |  |  |
  Yes | 0(0.00) | 2(1.01) |  | 0.500c |
 Maternal passive smoking | ||||
  No | 61(34.08) | 76(37.52) |  |  |
  Yes | 118(65.92) | 128(62.75) | 0.419 | 0.518 |
Dietary exposure during pregnancy | ||||
 Meat intake (times/week) | ||||
  ≤ 1 | 125(69.83) | 120(59.11) |  |  |
  2~7 | 54(30.17) | 83(40.89) | 4.752 | 0.029 |
 Eggs or milk intake (times/week) | ||||
  < 4 | 94(52.51) | 69(33.82) |  |  |
  4~7 | 85(47.49) | 135(66.18) | 13.624 |  < 0.001 |
 Fresh vegetables intake (times/week) | ||||
  ≤ 5 | 114(63.69) | 126(61.76) |  |  |
  6~7 | 65(36.31) | 78(38.24) | 0.151 | 0.698 |
 Fresh fruit intake (times/week) | ||||
  < 4 | 56(31.46) | 54(26.47) |  |  |
  4~7 | 122(68.54) | 150(73.53) | 1.154 | 0.283 |