Table 2

Results of multivariable analysis for risk or protective factors for injury among your children (n=5593)

VariablesNo injury n=5898
n(%)
Injury n=406
n(%)
Model 1
Unadjusted IRR (95% CI)
Model 2
Adjusted IRR (95% CI)
Model 3
Adjusted IRR (95% CI)
With interaction
Demographics
 GenderFemale2852 (93.9)184 (6.1)111
Male3046 (93.2)222 (6.8)1.12 (0.93 to 1.35)1.17 (0.95 to 1.44)1.19 (0.96 to 1.46)
 Maternal age<25 years1069 (91.1)105 (8.9) 1.63 (1.24 to 2.15) 1.40 (1.01 to 1.99) 1.54 (1.20 to 2.16)
25 to 34 years3310 (93.9)213 (6.1)1.10 (0.87 to 1.40)1.18 (0.87 to 1.48)1.17 (0.88 to 1.53)
≥ 35 years1518 (94.5)88 (5.5)1
 Maternal education levelNo secondary school375 (90.1)41 (9.9) 1.54 (1.06 to 2.23) 0.68 (0.41 to 1.13)0.63 (0.38 to 1.04)
Secondary school1381 (93.9)89 (6.1)0.94 (0.69 to 1.29)0.66 (0.46 to 0.97)0.63 (0.43 to 0.92)
Diploma/Trade1814 (93.6)123 (6.4)0.99 (0.74 to 1.32)0.72 (0.51 to 1.03)0.71 (0.50 to 1.00)
Bachelors degree1362 (93.9)88 (6.1)0.95 (0.69 to 1.29)0.89 (0.64 to 1.26)0.85 (0.63 to 1.25)
Higher degree947 (93.6)65 (6.4)111
 Maternal ethnicityEuropean3240 (94.1)203 (5.9)111
Māori775 (91.4)73 (8.6) 1.50 (1.13 to 1.89) 1.22 (0.90 to 1.64)1.17 (0.87 to 1.59)
Pacific786 (90.7)80 (9.3) 1.57 (1.22 to 2.01) 1.12 (0.80 to 1.56)1.12 (0.80 to 1.56)
Asian877 (96.1)36 (3.9) 0.64 (0.45 to 0.92) 0.66 (0.45 to 0.99) 0.67 (0.45 to 0.99)
Others202 (93.5)14 (6.5)1.09 (0.62 to 1.90)0.89 (0.64 to 1.26)0.81 (0.42 to 1.58)
Early childhood factors
 Birth complications for baby*No748 (92.9)57 (7.1)1
Yes5018 (93.6)342 (6.4)0.90 (0.69 to 1.18)
 Gestational agePreterm294 (95.2)15 (4.9)1
Term5448 (93.5)380 (6.5)1.34 (0.81 to 2.22)
Post-term146 (93.6)10 (6.4)1.32 (0.61 to 2.87)
 Birth weightLow202 (92.2)17 (7.8)1.314 (0.75 to 2.29)
Normal4693 (93.5)325 (6.5)1.081 (0.82 to 1.43)
High999 (94.0)64 (6.0)1
Maternal well-being
 Smoking status during pregnancyCurrent smoker507 (89.3)61 (10.7) 1.94 (1.48 to 2.54) 1.36 (1.10 to 1.85) 1.50 (1.08 to 1.06)
Former smoker518 (92.5)42 (7.5) 1.42 (1.03 to 1.94) 1.20 (0.85 to 1.68)1.15 (0.82 to 1.63)
Non-smoker4379 (94.6)248 (5.4)111
 Maternal healthPoor to fair551 (89.4)65 (10.6) 1.76 (1.37 to 2.26)
Good to excellent5333 (94.0)341 (6.0)1
 Maternal stress score†13.01 (6.4)14.59 (6.3) 1.04 (1.02 to 1.05)
  Maternal depression‡No4526 (94.33)272 (5.67) 1.46 (1.14 to 1.86) 1.03 (1.01 to 1.05) 1.05 (0.79 to 1.41)
Yes823 (91.75)74 (8.25)111
  Relationship statusSingle262 (89.4)31 (10.6) 1.73 (1.20 to 2.48) 1.19 (0.79 to 1.80)0.90 (0.52 to 1.57)
With partner5145 (94.1)322 (5.9)111
Socioeconomic status
 Employment statusEmployed2391 (93.0)180 (7.0)111
Not employed3314 (94.2)203 (5.8)1.19 (0.98 to 1.45)1.13 (0.91 to 1.41)0.90 (0.72 to 1.13)
Family stress10.56 (4.2)11.10 (4.0) 1.03 (1.00 to 1.05) 1.01 (0.98 to 1.03)
 Household Income tested benefitNo4966 (94.2)305 (5.8) 1.64 (1.16 to 2.34)
Yes294 (90.5)31 (9.5)1
 Deprivation indexLow (1-3)1518 (94.6)86 (5.4)11 1
Medium (4-7)2214 (94.6)127 (5.4)1.01 (0.78 to 1.32)1.08 (0.80 to 1.44)1.07 (0.80 to 1.43)
High (8-10)2162 (91.8)193 (8.2) 1.52 (1.20 to 1.95) 1.38 (1.02 to 1.87) 1.35 (1.00 to 1.82)
 DwellingOwnership2865 (94.4)169 (5.6)111
Private rental2065 (93.9)135 (6.1)1.10 (0.89 to 1.37)0.98 (0.66 to 1.45)0.96 (0.65 to 1.21)
Public rental382 (91.4)36 (8.6) 1.55 (1.10 to 2.18) 0.98 (0.78 to 1.23)0.96 (0.76 to 1.43)
 Interaction effectWith partnerwith no maternal depression1
Single parent with depression 2.20 (1.04 to 4.64)
Deviance goodness-of-fit1846.1 (p=1.000)1840(p=1.000)
Pearson goodness-of-fit5317.57 (p=0.995)5301.1(p=0.995)
  • Significant factors are in bold.

  • *admission to neonatal intensive care, hypoglycaemia, infections, jaundice, meconium aspiration, breathing difficulties and distress, and the use of a ventilator captured during the 16 month data collection wave.

  • †maternal stress score = Perceived stress anxiety.

  • ‡maternal depression score=Edinburgh Postnatal Depression Scale20 (10-item questions total score=30).

  • 1, reference group; IRR, incidence Risk Ratio; NCEA, National Certificate of Educational Achievement.