Table 3

Effect of intervention (after vs before) on probability of quitting by delivery

VariableOR95% CIPr(>|z|)
Intercept: baseline0.130.09 to 0.19<0.001
After implementation of intervention, compared with before
After intervention1.811.55 to 2.12<0.001
Ethnic group, compared with white
Caucasian2.521.837 to 3.44<0.001
SEP category (based on IMD score) compared with middle three-fifths of distribution
Least deprived fifth2.752.386 to 3.18<0.001
Most deprived fifth0.40.42 to 0.65<0.001
Maternal age category, compared with 21–30 years
15–20 years0.750.655 to 0.87<0.001
31–40 years1.431.29 to 1.60<0.001
41–55 years1.140.76 to 1.710.526
Engagement with smoking cessation services, compared with not referred
Referred, quit date4.183.53 to 4.94<0.001
Referred, no quit date3.332.99 to 3.71<0.001
Time since start of intervention, compared with before
Each additional month1.021.00 to 1.03<0.050
  • 9967 valid cases included in model (6.6% cases with missing data excluded).

  • SEP, socioeconomic position (categories defined by fifths of Index of Multiple Deprivation (IMD) score)