Infertility after spontaneous and induced abortion
Usage
data(infert)
Format
| 1. | Education | 0 = 0-5 years |
| | | 1 = 6-11 years |
| | | 2 = 12+ years |
| 2. | age | age in years of case |
| 3. | parity | count |
| 4. | number of prior | 0 = 0 |
| | induced abortions | 1 = 1 |
| | | 2 = 2 or more |
| 5. | case status | 1 = case |
| | | 0 = control |
| 6. | number of prior | 0 = 0 |
| | spontaneous abortions | 1 = 1 |
| | | 2 = 2 or more |
| 7. | matched set number | 1-83 |
| 8. | stratum number | 1-63 |
Description
This is a matched case-control study dating from before the
availability of conditional logistic regression.Note
One case with two prior spontaneous abortions and two prior induced
abortions is omitted.Source
Trichopoulos et al. (1976) Br. J. of Obst. and Gynaec. vol.83,
pp. 645-650.Examples
data(infert)
model1 <- glm(case ~ spontaneous+induced, data=infert,family=binomial())
summary(model1)
## adjusted for other potential confounders:
summary(model2 <- glm(case ~ age+parity+education+spontaneous+induced,
data=infert,family=binomial()))
## Really should be analysed by conditional logistic regression
## which is equivalent to a Cox model :
if(require(survival4)){
faketime <- rep(42,nrow(infert))
model3 <- coxph(Surv(faketime,case)~spontaneous+induced+strata(stratum),
data=infert,method="exact")
summary(model3)
detach()# survival4 (conflicts)
}