Table 1 |
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|
Characteristics of all singleton births, Sydney, 1998 to 2000 |
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| Preterm (<37 weeks) n = 6 011 |
Term (3742 weeks) n = 117 829 |
OR+ (95% CI) |
|
|
|
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| Maternal age (years) Mean ± SD |
30.3 ± 5.8 |
30.2 ± 5.2 |
1.02 |
| Range |
15.0–50.1 |
12.1–53.3 |
(1.02–1.03) |
| Maternal smoking during pregnancy Number (%) |
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| Yes |
1 103 (18.4) |
14 475 (12.3) |
1.62 (1.51–1.74) |
| No |
4 905 (81.6) |
103 332 (87.7) |
|
| Sex of infant Number (%) |
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| Male |
3 369 (56.1) |
60 415 (51.3) |
1.22 (1.16–1.29) |
| Female |
2 634 (43.9) |
57 367 (48.7) |
|
| Mother is Aboriginal or Torres Strait Islander Number (%) |
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| Yes |
71 (1.2) |
746 (0.6) |
1.60 (1.24–2.07) |
| No |
5 934 (98.8) |
116 985 (99.4) |
|
| Gestational age at first antenatal visit Number (%) |
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| >20 weeks |
728 (12.5) |
13473 (11.5) |
1.05 (0.98–1.14) |
| ≤20 weeks |
5110 (87.5) |
103 642 (88.5) |
|
| Previous pregnancy Number (%) |
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| No |
2897 (48.2) |
50 060 (42.5) |
1.38 (1.30–1.45) |
| Yes |
3111 (51.8) |
67 737 (57.5) |
|
| IRSD Quintile Number (%) |
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| 5* (Least disadvantaged) |
1928 (32.1) |
42 632 (36.2) |
1.00 |
| 4 |
1363 (22.7) |
25 761 (21.9) |
1.18 (1.09–1.27) |
| 3 |
1009 (16.8) |
18 817 (16.0) |
1.18 (1.09–1.28) |
| 2 |
727 (12.1) |
13 090 (11.1) |
1.26 (1.15–1.38) |
| 1 (Most disadvantaged) |
984 (16.4) |
17 529 (14.9) |
1.27 (1.17–1.38) |
| Season of conception Number (%) |
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| Summer* |
1540 (25.6) |
28 764 (24.4) |
1.00 |
| Autumn |
1513 (25.2) |
29 453 (25.0) |
0.97 (0.89–1.07) |
| Winter |
1540 (25.6) |
29 511 (25.1) |
0.92 (0.79–1.07) |
| Spring |
1418 (23.6) |
30 101 (25.6) |
0.86 (0.77–0.96) |
|
|
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|
*Referent group; +Adjusted for all other covariates in Table 1 |
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|
Jalaludin et al. Environmental Health 2007 6:16 doi:10.1186/1476-069X-6-16 |
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