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Table 7 Fixed Effects for Models with Reduced Covariates

From: A multilevel non-hierarchical study of birth weight and socioeconomic status

  Level Model IV Model IVa Model IVb
   β (grams) (P-Value) β (grams) (P-Value) β (grams) (P-Value)
  AIC 21594.53 21519.07 21515.5
Gender Male v Female 142.89(22.36; < 0.001) 155.81(22.04; < 0.001) 147.05(22.10; < 0.001)
Gestational duration Weeks   56.23(6.60; < 0.001)  
Birth order - < 0.001 < 0.001 < 0.001
  1v3+ -169.84(34.43; < 0.001) -178.72(33.76; < 0.001) -182.39(34.10; < 0.001)
  2v3+ -115.09(31.58; < 0.001) -102.30(31.17;0.001) -130.50(31.37; < 0.001)
Year of birth   0.021 0.018 0.025
  (1975 v 1983) -80.33(55.82;0.152) -83.91(54.71;0.127) -85.40(55.12;0.123)
  (1976 v 1983) 50.70(56.64;0.372) 39.70(55.55;0.476) 60.70(55.88;0.279)
  (1977 v 1983) -67.24(48.62;0.169) -85.48(47.84;0.076) -49.98(48.21;0.302)
  (1978 v 1983) -43.56(46.13;0.347) -65.23(45.43;0.153) -29.49(45.63;0.519)
  (1979 v 1983) -76.52(42.42;0.073) -78.76(41.77;0.061) -67.50(42.02;0.110)
  (1980 v 1983) 43.95(40.58;0.281) 35.45(40.13;0.378) 50.35(40.25;0.213)
  (1981 v 1983) 10.01(43.24;0.817) -0.34(42.71;0.994) 17.47(42.83;0.684)
  (1982 v 1983) 21.80(42.41;0.608) 6.61(41.77;0.874) 24.56(41.94;0.559)
Adequate prenatal care Yes v No 108.62(37.24;0.004) 99.59(36.52;0.006) 95.28(36.76;0.010)
Maternal age Years -4.10(3.44;0.233) -2.86(3.34;0.391) -4.95(3.37;0.142)
Maternal race White v NonWhite 211.69(67.95;0.002) 197.4(65.89;0.003) 243.75(66.73; < 0.001)
Smoking category     < 0.001
  Avg < 10 cig v None    -150.15(34.85; < 0.001)
  Avg 11-20 cig v None    -248.18(45.08; < 0.001)
  Avg 21+ cig v None    -254.02(71.42;0.001)
Maternal education   0.229 0.092 0.624
  < HS v College -137.77(82.55;0.097) -176(80.60;0.031) -61.88(82.02;0.452)
  HS Grad v College 0.64(28.28;0.982) -10.35(27.55;0.708) 11.80(27.81;0.672)
Paternal occupation   0.116 0.033 0.243
  Blue v White Collar -56.66(28.59;0.049) -66.44(27.87;0.018) -43.24(28.16;0.127)
  Other v White Collar -2.81(36.96;0.939) 7.33(36.07;0.839) 5.01(36.39;0.891)
% Adults living in poverty > 0% v 0% -43.96(29.48;0.136) -39.04(28.66;0.173) -52.10(28.97;0.072)
Mean family income (quartiles)   0.945 0.914 0.957
  Q1vQ4 -11.86(39.32;0.763) -20.49(38.25;0.593) -7.88(38.64;0.839)
  Q2vQ4 0.59(36.71;0.987) -5.86(35.66;0.870) 1.29(36.02;0.971)
  Q3vQ4 -19.08(39.04;0.626) -22.55(37.96;0.553) -17.43(38.35;0.65)
% Adults graduated   0.019 0.094 0.054
4 year college (quartiles) Q1vQ4 -81.91(38.54;0.035) -66.80(37.54;0.077) -67.30(37.92;0.078)
  Q2vQ4 -11.96(36.26;0.742) -15.48(35.28;0.661) -1.58(35.64;0.965)
  Q3vQ4 44.29(39.57;0.265) 30.93(38.49;0.423) 41.58(38.85;0.286)
% Unemployment ≤ 10% v > 10% 26.84(34.02;0.430) 30.37(33.11;0.359) 23.33(33.43;0.485)
  1. Type III p-value for overall variation between categories