Table 3

Bivariate associations of SGA with census dissemination area average income and maternal risk factors
SGA (n = 4237) Not SGA (n = 54802)
n (%) n (%) n (%) 2-sided p*
Average income quintile
 1 ($6,196–$24,444) 1018 (24) 10426 (19) <0.0001
 2 ($24,444–$28,440) 916 (22) 10594 (19)
 3 ($28,440–$32,954) 876 (21) 11077 (20)
 4 ($32,986–$38,832) 752 (18) 11411 (21)
 5 ($38,837–$509,269) 675 (16) 11294 (21)
Smoking during pregnancy 326 (8) 3152 (6) <0.0001
Maternal age
 <20 75 (2) 852 (2) 0.0002
 20–35 3167 (75) 39508 (72)
 ≥ 35 995 (23) 14442 (26)
Parity
 0 2784 (66) 26712 (49) <0.0001
 ≥ 1 1453 (34) 28090 (51)
Pre-pregnancy BMI (kg/m2)
 Underweight (<18.5) 531 (13) 3567 (7) <0.0001
 Normal weight (18.5–25) 2805 (66) 34913 (64)
 Overweight (25–30) 632 (15) 10862 (20)
 Obese (≥30) 269 (6) 5460 (10)
Height (cm) (mean (SD)) 161 (7) 164 (7) <0.0001
Diabetes/hypertension
 Neither 3422 (81) 46741 (85) <0.0001
 Diabetes only 364 (9) 5251 (10)
 Hypertension only 390 (9) 2263 (4)
 Diabetes & hypertension 61 (1) 547 (1)
Oligohydramnios 339 (8) 1044 (2) <0.0001
Placenta disorder 135 (3) 1116 (2) <0.0001

* Chi squared test for categorical variables and analysis of variance (ANOVA) for continuous variable (height).

Hayward et al.

Hayward et al. BMC Public Health 2012 12:333   doi:10.1186/1471-2458-12-333

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