Exercise: Caesarean section and obesity, 5

Question 5: What is the estimated difference in risk of a caesarean between two women with no history of vaginal delivery, both induced, and differing in BMI by one Kg/m2?

Suggested answer

The estimated differnce it contained in the output table:

Variables in the Equation
  B S.E. Wald df Sig. Exp(B)
bmi .088 .020 19.525 1 .000 1.092
iol .647 .214 9.139 1 .003 1.910
prevag -1.796 .298 36.311 1 .000 .166
Constant     -3.700       .534     47.953             1     .000     .025
a. Variable(s) entered on step 1: bmi, iol, prevag.

The difference in risk is expressed as an odds ratio. These are found in the column headed "Exp(B)". The estimated odds ratio is 1.092. We estimate that the odds of a caesarean section are multiplied by 1.092 for each unit difference in BMI between the two women.

Back to Exercise: Caesarean section and obesity.

To Applied Biostatistics index.

To Martin Bland's M.Sc. index.

To Martin Bland's home page.

This page maintained by Martin Bland.
Last updated: 12 December, 2006.

Back to top.