Skip to main content

Table 2 Distribution of selected characteristics of the study population by cooking fuel types

From: Exposure to cooking fuels and birth weight in Lanzhou, China: a birth cohort study

Characteristic Gas Coal Biomass Electromagnetic Other P*
N (%) N (%) N (%) N (%) N (%)
Birth weight       
 LBW 371(4.7) 70(19.6) 42(35.0) 53(10.9) 114(11.1)  
 NBW 6965(88.1) 270(75.4) 73(60.8) 408(83.8) 865(84.6) <0.001
 Macrosomia 571(7.2) 18(5.0) 5(4.2) 26 (5.3) 44(4.3)  
Birth weight       
 SGA 509(6.4) 55(15.4) 22(18.4) 56(11.5) 114(10.2)  
 AGA 6232(78.8) 264(73.7) 88(73.3) 377(77.4) 814(79.6) <0.001
 LGA 1166(14.8) 39(10.9) 10(8.3) 54(11.1) 105(10.2)  
Preterm       
 No 7334(92.8) 267(74.6) 78(65.0) 417(85.6) 889(86.9)  
 Yes 573(7.2) 91(25.4) 42(35.0) 70(14.4) 134(13.1) <0.001
Maternal age (years)       
 <25 1040(13.2) 136(38.0) 42(35.0) 226(27.9) 1580(22.1)  
 25–29 3939(49.8) 108(30.2) 42(35.0) 438(43.1) 4737(42.8) <0.001
 ≥30 2928(37.0) 114(31.8) 36(30.0) 359(29.0) 3578(35.1)  
Highest education level       
 High school or less 2706(34.2) 302(84.4) 108(90.0) 277(56.9) 473(46.2)  
 College or above 5111(64.7) 55(15.4) 10(8.3) 205(42.1) 466(45.6) <0.001
 Missing 90(1.1) 1(0.3) 2(1.7) 5(1.0) 84(8.2)  
Family income (RMB per capita)       
 <3000 3788(47.9) 264(73.7) 99(82.5) 330(67.8) 495(48.4)  
 ≥3,000 3454(43.7) 58(16.2) 5(4.2) 137(28.1) 318(31.1) <0.001
 Missing 665(8.4) 36(10.1) 16(13.3) 20(4.1) 210(20.5)  
Maternal pre-pregnancy BMI (kg/m2)       
 ≤18.5 1640(20.7) 63(17.6) 16(13.2) 93(19.1) 208(20.3)  
 18.6–23.9 5276(66.7) 228(63.7) 67(55.8) 336(69.0) 593(58.0)  
 ≥24 863(10.9) 36(10.0) 24(20.0) 49(10.1) 71(6.9) <0.001
 Missing 128(1.7) 31(8.7) 13(10.8) 9(1.8) 151(14.8)  
Maternal weight gain during pregnancy (kg)       
 <15 2262(28.6) 158(44.1) 55(45.8) 204(41.9) 311(30.5)  
 15–18.5 2573(32.6) 71(19.8) 20(16.7) 138(28.3) 248(24.2)  
 >18.5 2910(36.9) 89(24.9) 25(20.8) 131(26.9) 298(29.1) <0.001
 Missing 162(2.9) 40(11.2) 20(16.7) 14(2.9) 166(16.2)  
Vitamin supplement during pregnancy       
 No 963(12.2) 117(32.7) 49(40.8) 82(16.8) 255(24.9)  
 Yes 6920(87.5) 239(66.8) 71(59.2) 403(82.8) 683 (66.8) <0.001
 Missing 24(0.3) 2(0.5) 0(0.0) 2(0.4) 85(8.3)  
Smoking (Active and passive)       
 No 6416(81.1) 259(72.3) 91(75.8) 257(73.3) 844(82.5)  
 Yes 1491(18.9) 99(27.7) 29(24.2) 130(26.7) 179(17.5) <0.001
Alcohol during pregnancy       
 No 7871(99.6) 357(99.7) 120(100.0) 487(100.0) 951(93.0)  
 Yes 18(0.2) 0(0.0) 0(0.0) 0(0.0) 2(0.2) 0.697
 Missing 18(0.2) 1(0.3) 0(0.0) 0(0.0) 70(6.8)  
Gestational Diabetes       
 No 7828(99.0) 351(99.7) 118(98.3) 484(99.4) 1013(99.0)  
 Yes 79(1.0) 1(0.3) 2(1.7) 3(0.6) 10(1.0) 0.539
Preeclampsia       
 No 7710(97.5) 316(88.3) 101 (84.2) 464(95.3) 983(96.1)  
 Yes 197(2.5) 42(11.7) 19(15.8) 23(4.7) 321(3.9) <0.001
Parity       
 Primiparous 5960(75.4) 186(52.0) 52(43.3) 339(69.6) 688(67.3)  
 Multiparous 1947(24.6) 172(48.0) 68(56.7) 148(30.4) 335(32.7) <0.001
Caesarean section       
 No 4921(62.3) 194(54.2) 54(45.0) 307(63.0) 592(57.9)  
 Yes 2927(37.0) 160(44.7) 65(54.2) 178(36.6) 417(40.8) <0.001
 Missing 59(0.7) 4(1.1) 1(0.8) 2(0.4) 14(1.3)  
Gender       
 Boy 4162(52.6) 203(56.7) 69(56.7) 257 (57.5) 512(52.8)  
 Girl 3732(47.2) 155(43.3) 51(43.3) 226(42.5) 509(46.4) 0.190
 Missing 13(0.2) 0(0.0) 0(0.0) 4(0.0) 2(0.8)  
Ventilation       
 No 751(9.5) 234(65.4) 98(81.7) 222(45.6) 713(69.7)  
 Yes 7156(90.5) 124(34.6) 22(18.3) 265(54.4) 310(30.3) <0.001
  1. *The analysis did not account for missing data