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Table 2 The child and family characteristics in the study population (n = 114,311)

From: Associations between gestational age and childhood sleep: a national retrospective cohort study

Characteristics Total Sex p Gestational age at birth p
(n = 114,311) Male Female Very-preterm Moderate-preterm Preterm Early-term Full-term Late-term Post-term
  (n = 59,694) (n = 54,617) <31W 32–33W 34–36W 37–38W 39–40W 41–41W >41W
    (n = 2379) (n = 1893) (n = 10,238) (n = 29,179) (n = 58,043) (n = 7016) (n = 5563)
Child characteristics
Children’s age (M, SD) 4.408, 0.798 4.413, 0.797 4.403, 0.800 0.0423 4.446, 0.790 4.501, 0.781 4.490, 0.801 4.411, 0.804 4.389, 0.797 4.347, 0.782 4.472, 0.789 <0.001
Gender (n%)             <0.001
Male 59,694, 52.221 59,694, 100.000 0, 0.000   1268, 53.3 1014, 53.566 5568, 54.386 16,010, 54.868 29,670, 51.117 3373, 48.076 2791, 50.171  
Female 54,617, 47.779 0, 0.000 54,617, 100.000   1111, 46.7 879, 46.434 4670, 45.614 13,169, 45.132 28,373, 48.883 3643, 51.924 2772, 49.829  
BMI (M, SD) 15.602, 1.607 15.754, 1.622 15.435, 1.574 <0.001 15.660, 1.709 15.661, 1.666 15.660, 1.702 15.609, 1.617 15.576, 1.576 15.582, 1.574 15.698, 1.669 <0.001
Right-handedness (n%)     <0.001         0.007
No 8187, 7.162 4763, 7.979 3424, 6.269   212, 8.911 148, 7.818 763, 7.453 2103, 7.207 4039, 6.959 520, 7.412 402, 7.226  
Yes 106,124, 92.838 54,931, 92.021 51,193, 93.731   2167, 91.089 1745, 92.182 9475, 92.547 27,076, 92.793 54,004, 93.041 6496, 92.588 5161, 92.774  
Eyesight (n%)     0.506         0.147
Normal 103,199, 90.279 53,858, 90.223 49,341, 90.34   2133, 89.66 1691, 89.329 9202, 89.881 26,353, 90.315 52,463, 90.386 6302, 89.823 5055, 90.868  
Abnormal 11,112, 9.721 5836, 9.777 5276, 9.66   246, 10.34 202, 10.671 1036, 10.119 2826, 9.685 5580, 9.614 714, 10.177 508, 9.132  
Birth weight (n%)     <0.001         <0.001
<2500g 3700, 3.237 1727, 2.893 1973, 3.612   365, 15.343 383, 20.232 1019, 9.953 925, 3.17 808, 1.392 93, 1.326 107, 1.923  
≥2500g 110,611, 96.763 57,967, 97.107 52,644, 96.388   2014, 84.657 1510, 79.768 9219, 90.047 28,254, 96.83 57,235, 98.608 6923, 98.674 5456, 98.077  
Delivery mode     <0.001         <0.001
Vaginal delivery 59,625, 52.160 30,421, 50.962 29,204, 53.471   1208, 50.778 928, 49.023 5070, 49.521 13,925, 47.723 31,639, 54.51 3893, 55.487 2962, 53.245  
Delivery with caesarean section 54,686, 47.840 29,273, 49.038 25,413, 46.529   1171, 49.222 965, 50.977 5168, 50.479 15,254, 52.277 26,404, 45.49 3123, 44.513 2601, 46.755  
NICU admission     <0.001         <0.001
No 102,833, 89.959 53,301, 89.290 49,532, 90.69   1891, 79.487 1399, 73.904 8206, 80.152 26,290, 90.099 53,501, 92.175 6420, 91.505 5126, 92.145  
Yes 11,478, 10.041 6393, 10.710 5085, 9.31   488, 20.513 494, 26.096 2032, 19.848 2889, 9.901 4542, 7.825 596, 8.495 437, 7.855  
Other developmental disorders     <0.001         <0.001
No 113,565, 99.347 59,244, 99.246 54,321, 99.458   2359, 99.159 1867, 98.627 10174, 99.375 28,971, 99.287 57,702, 99.413 6977, 99.444 5515, 99.137  
Yes 746, 0.653 450, 0.754 296, 0.542   20, 0.841 26, 1.373 64, 0.625 208, 0.713 341, 0.587 39, 0.556 48, 0.863  
Co-sleeping     0.427         0.142
Yes 93,755, 82.020 48,941, 81.900 44,814, 82.000   1935, 81.337 1530, 80.824 8395, 81.998 23,914, 81.956 47,717, 82.21 5754, 82.013 4510, 81.071  
No 20,556, 17.980 10,753, 18,100 9803, 18.000   444, 18.663 363, 19.176 1843, 18.002 5265, 18.044 10,326, 17.79 1262, 17.987 1053, 18.929  
Family characteristics
Higher education of mother (n%)     0.00195         <0.001
No 51,393, 44.959 27,098, 45.395 24,295, 44.482   1086, 45.649 862, 45.536 4578, 44.716 13,540, 46.403 24,070, 41.469 2929, 41.747 2870, 51.591  
Yes 62,918, 55.041 32,596, 54.605 30,322, 55.518   1293, 54.351 1031, 54.464 5660, 55.284 15,639, 53.597 33,973, 58.531 4087, 58.253 2693, 48.409  
Higher education of father (n%)     0.00498         <0.001
No 52,335, 45.783 27,566, 46.179 24,769, 45.35   1061, 44.599 851, 44.955 4496, 43.915 13,709, 46.982 24,759, 42.656 2940, 41.904 2825, 50.782  
Yes 61,976, 54.217 32,128, 53.821 29,848, 54.65   1318, 55.401 1042, 55.045 5742, 56.085 15,470, 53.018 33,284, 57.344 4076, 58.096 2738, 49.218  
Mother’s occupation (n%)     0.00255         0.013
Employed 71,455, 62.509 37,561, 62.923 33,894, 62.058   1505, 63.262 1165, 61.543 6231, 60.861 18,247, 62.535 36,361, 62.645 4439, 63.27 3507, 63.042  
Unemployed 42,856, 37.491 22,133, 37.077 20,723, 37.942   874, 36.738 728, 38.457 4007, 39.139 10,932, 37.465 21,682, 37.355 2577, 36.73 2056, 36.958  
Father’s occupation (n%)     0.249         <0.001
Employed 90,554, 79.217 47,367, 79.35 43,187, 79.072   1834, 77.091 1452, 76.704 7755, 75.747 23,101, 79.17 46,381, 79.908 5655, 80.601 4376, 78.663  
Unemployed 23,757, 20.783 12,327, 20.65 11,430, 20.928   545, 22.909 441, 23.296 2483, 24.253 6078, 20.83 11,662, 20.092 1361, 19.399 1187, 21.337  
Family annual per capita income (RMB) b(n%)     0.0326         <0.001
Below 21,988, 19.235 11,340, 18.997 10,648, 19.496   526, 22.11 431, 22.768 2371, 23.159 5418, 18.568 10,683, 18.405 1296, 18.472 1263, 22.704  
Above or equal to 92,323, 80.765 48,354, 81.003 43,969, 80.504   1853, 77.89 1462, 77.232 7867, 76.841 23,761, 81.432 47,360, 81.595 5720, 81.528 4300, 77.296  
Family structure (n%)     0.0395         
   <0.001
Single families 2807, 2.456 1412, 2.365 1395, 2.554   89, 3.741 59, 3.117 340, 3.321 748, 2.563 1242, 2.140 155, 2.209 174, 3.128  
Nuclear families 70,142, 61.361 36,724, 61.520 33,418, 61.186   1544, 64.901 1225, 64.712 6581, 64.28 17,989, 61.651 35,235, 60.705 4058, 57.839 3510, 63.095  
Extended families 41,362, 36.184 21,558, 36.114 19,804, 36.260   746, 31.358 609, 32.171 3317, 32.399 10,442, 35.786 21,566, 37.155 2803, 39.952 1879, 33.777  
The number of children in the family (n%)     <0.001         <0.001
One 64,273, 56.226 34,319, 57.492 29,954, 54.844   1390, 58.428 1125, 59.429 5616, 54.854 15,516, 53.175 33,105, 57.035 4201, 59.877 3320, 59.680  
Two or more 50,038, 43.774 25,375, 42.508 24,663, 45.156   989, 41.572 768, 40.571 4622, 45.146 13,663, 46.825 24,938, 42.965 2815, 40.123 2243, 40.320  
Maternal health characteristics
Maternal age at delivery (n%)     0.414         <0.001
<30 84,676, 74.075 44,158, 73.974 40,518, 74.186   1766, 74.233 1354, 71.527 7068, 69.037 20,500, 70.256 44,021, 75.842 5686, 81.043 4281, 76.955  
30–34 21,956, 19.207 11,582, 19.402 10,374, 18.994   417, 17.528 367, 19.387 2224, 21.723 6293, 21.567 10,666, 18.376 1049, 14.952 940, 16.897  
≥35 7679, 6.718 3954, 6.624 3725, 6.820   196, 8.239 172, 9.086 946, 9.24 2386, 8.177 3356, 5.782 281, 4.005 342, 6.148  
Smoking or passive smoking during pregnancy (n%)     0.685         <0.001
No 82,461, 72.137 43,031, 72.086 39,430, 72.194   1677, 70.492 1336, 70.576 7154, 69.877 21,197, 72.645 42,124, 72.574 5019, 71.536 3954, 71.077  
Yes 31,850, 27.863 16,663, 27.914 15,187, 27.806   702, 29.508 557, 29.424 3084, 30.123 7982, 27.355 15,919, 27.426 1997, 28.464 1609, 28.923  
Maternal complications during pregnancy c(n%)     0.147         <0.001
No 108,934, 95.296 56,938, 95.383 51,996, 95.201   2242, 94.241 1755, 92.71 9612, 93.886 27,515, 94.297 55,634, 95.85 6783, 96.679 5393, 96.944  
Yes 5377, 4.704 2756, 4.617 2621, 4.799   137, 5.759 138, 7.29 626, 6.114 1664, 5.703 2409, 4.15 233, 3.321 170, 3.056  
  1. Other developmental disorders included attention deficit syndrome, attention deficit and hyperactivity disorder, learning disabilities