Table 1.
General characteristics of the study children.
| Characteristics (variables) | Total (n=3725) | Asthma/wheezing | Chi-square/t test (df) | P value |
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Yes (n=392) | No (n=3333) |
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| Sex of children, n (%) | 30.63 (1) | <.001 |
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Boys | 1984 (53.26) | 261 (13.16) | 1723 (86.84) |
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Girl | 1741 (46.74) | 131 (7.52) | 1610 (92.48) |
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| Maternal age (years), n (%) | 7.19 (3) | .07 |
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18-25 | 193 (5.18) | 22 (11.40) | 171 (88.60) |
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26-30 | 1253 (33.64) | 124 (9.90) | 1129 (90.10) |
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31-35 | 1304 (35.01) | 159 (12.19) | 1145 (87.81) |
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>35 | 975 (26.17) | 87 (8.92) | 888 (91.08) |
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| Maternal occupation, n (%) | 12.94 (6) | .04 |
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Manual worker | 183 (4.91) | 22 (12.02) | 161 (87.98) |
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Government official and clerk | 78 (2.09) | 12 (15.38) | 66 (88.62) |
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Housewife | 372 (9.99) | 43 (11.56) | 329 (88.44) |
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Unemployment | 278 (7.46) | 43 (15.47) | 235 (84.53) |
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Technician | 689 (18.50) | 65 (9.43) | 624 (90.57) |
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Business (commercial activities) | 2008 (53.91) | 193 (9.61) | 1815 (90.39) |
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Others | 117 (3.14) | 14 (11.97) | 103 (88.03) |
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| Parity, n (%) | 7.86 (2) | .02 |
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1 | 1132 (30.39) | 96 (8.48) | 1036 (91.52) |
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2 | 2220 (59.60) | 249 (11.22) | 1971 (88.78) |
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≥3 | 373 (10.01) | 47 (12.60) | 326 (87.40) |
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| Gravidity, n (%) | 3.84 (3) | .28 |
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1 | 1104 (29.64) | 101 (9.15) | 1003 (90.85) |
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2 | 1432 (38.44) | 163 (11.38) | 1269 (88.62) |
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3 | 792 (21.26) | 82 (10.35) | 710 (89.65) |
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≥4 | 397 (10.66) | 46 (11.59) | 351 (88.41) |
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| Yearly income per capita (×1000 Yuana), n (%) | N/Ab | .43c |
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<30 | 193 (5.18) | 22 (11.40) | 171 (88.60) |
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30~ | 2228 (59.81) | 248 (11.13) | 1980 (88.87) |
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100~ | 1088 (29.21) | 100 (9.19) | 988 (90.81) |
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≥200~ | 178 (4.78) | 17 (9.55) | 161 (90.45) |
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Refused to answer/missing | 38 (1.02) | 5 (13.16) | 33 (86.84) |
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| Feeding method, n (%) | 13.05 (3) | .01 |
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Artificial feeding | 400 (10.74) | 60 (15.00) | 340 (85.00) |
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Breastfeeding | 449 (12.05) | 45 (10.02) | 404 (89.98) |
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Mixed feeding | 431 (11.57) | 32 (7.42) | 399 (92.58) |
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Refused to answer/missing | 2445 (65.64) | 255 (10.43) | 2190 (89.57) |
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| Passive smoking, n (%) | 0.49 (1) | .49 |
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Yes | 2599 (69.77) | 267 (10.27) | 2332 (89.73) |
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No | 1126 (30.23) | 125 (11.10) | 1001 (88.90) |
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| Vegetable consumption (time/week), n (%) | 3.73 (3) | .29 |
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≤7 | 345 (9.26) | 35 (10.14) | 310 (89.86) |
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8-14 | 1313 (35.25) | 122 (9.29) | 1191 (90.71) |
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≥15 | 2005 (53.83) | 228 (11.37) | 1777 (88.63) |
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Refused to answer/missing | 62 (1.66) | 7 (11.29) | 55 (88.71) |
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| Fruit consumption (time/week), n (%) | 4.70 (3) | .20 |
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≤5 | 271 (7.28) | 24 (8.86) | 247 (91.14) |
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6-7 | 3041 (81.64) | 334 (10.98) | 2707 (89.02) |
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≥8 | 343 (9.21) | 26 (7.58) | 317 (92.42) |
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Refused to answer/missing | 70 (1.88) | 8 (11.43) | 62 (88.57) |
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| History of gestational diabetes mellitus, n (%) | N/A | .59c |
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No | 3516 (94.39) | 368 (10.47) | 3148 (89.53) |
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Yes | 197 (5.29) | 22 (11.17) | 175 (88.83) |
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Refused to answer/missing | 12 (0.32) | 2 (16.67) | 10 (83.33) |
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| History of maternal asthma, n (%) | 0.17 (1) | .68 |
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No | 3546 (95.19) | 371 (10.46) | 3175 (89.54) |
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Yes | 179 (4.81) | 21 (11.73) | 158 (88.27) |
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| Conception season, n (%) | 3.03 (1) | .08 |
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Warm (May to October) | 1775 (47.65) | 170 (9.58) | 1605 (90.42) |
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Cold (November to April) | 1950 (52.35) | 222 (11.38) | 1728 (88.62) |
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| Premature, n (%) | 1.93 (1) | .17 |
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No | 3520 (94.50) | 364 (10.34) | 3156 (89.66) |
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Yes | 205 (5.50) | 28 (13.66) | 177 (86.34) |
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| Age of children at end of follow-up (years), mean (SD) | 3.20 (0.78) | 1.48 (0.89) | 3.41 (0.44) | 42.21d (3723) | <.001 |
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| Gestation age of children at birth (ie, gestational weeks), mean (SD) | 39.74 (2.08) | 39.65 (1.61) | 39.75 (2.13) | 1.12d (3273) | .26 |
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a1 yuan=US $0.14.
bN/A: not applicable.
cFisher exact test.
dt-test for 2 independent samples (paired, 2-tailed).