| infert {datasets} | R Documentation |
This is a matched case-control study dating from before the availability of conditional logistic regression.
infert| 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 |
One case with two prior spontaneous abortions and two prior induced abortions is omitted.
Trichopoulos, D., Handanos, N., Danezis, J., Kalandidi, A., & Kalapothaki, V. (1976). Induced abortion and secondary infertility. British Journal of Obstetrics and Gynaecology, 83, 645–650. doi:10.1111/j.1471-0528.1976.tb00904.x.
require(stats)
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 in the survival package
if(require(survival)){
model3 <- clogit(case ~ spontaneous+induced+strata(stratum), data = infert)
print(summary(model3))
detach() # survival (conflicts)
}