Matched data on infant mortality, from seven parishes in Sweden, 1821--1894.
A data frame with 80 rows and five variables.
Triplet No. Each triplet consist of one infant whose mother died (a case), and two controls, i.e, infants whose mother did not die. Matched on covariates below.
Age (in days) of case when its mother died.
Age (in days) at death or right censoring (at age 365 days).
Follow-up ends with death (1) or right censoring (0).
dead for cases,
alive for controls.
Mother's age at infant's birth.
The infant's sex.
Birth parish, either Nedertornea or not Nedertornea.
Civil status of mother,
Socio-economic status of mother, either farmer or not farmer.
Year of birth of the infant.
From 5641 first-born in seven Swedish parishes 1820-1895, from Fleninge in the very south to Nedertorneå in the very north, those whose mother died during their first year of life were selected, in all 35 infants. To each of them, two controls were selected by matching on the given covariates.
Data originate from The Demographic Data Base, Umeå University, Umeå, Sweden, https://www.umu.se/enheten-for-demografi-och-aldrandeforskning/.
Broström, G. (1987). The influence of mother's death on infant mortality: A case study in matched data survival analysis. Scandinavian Journal of Statistics 14, 113-123.
data(infants) fit <- coxreg(Surv(enter, exit, event) ~ strata(stratum) + mother, data = infants) fit#> Call: #> coxreg(formula = Surv(enter, exit, event) ~ strata(stratum) + #> mother, data = infants) #> #> Covariate Mean Coef Rel.Risk S.E. Wald p #> mother #> alive 0.763 0 1 (reference) #> dead 0.237 2.605 13.534 0.757 0.001 #> #> Events 21 #> Total time at risk 21616 #> Max. log. likelihood -10.815 #> LR test statistic 19.65 #> Degrees of freedom 1 #> Overall p-value 9.31744e-06fit.w <- phreg(Surv(enter, exit, event) ~ mother + parish + ses, data = infants) summary(fit.w) ## Weibull proportional hazards model.#> Covariate Mean Coef Rel.Risk S.E. LR p #> mother 0.0000 #> alive 0.763 0 1 (reference) #> dead 0.237 2.262 9.601 0.507 #> parish 0.0000 #> other 0.723 0 1 (reference) #> Nedertornea 0.277 2.052 7.786 0.498 #> ses 0.5909 #> other 0.806 0 1 (reference) #> farmer 0.194 -0.346 0.708 0.665 #> #> Events 21 #> Total time at risk 21616 #> Max. log. likelihood -139.17 #> LR test statistic 33.46 #> Degrees of freedom 3 #> Overall p-value 2.57e-07