A parametric model for old age mortality in mediation analysis
2013 (English)Conference paper (Other academic)
Place, publisher, year, edition, pages
Research subject Statistics
IdentifiersURN: urn:nbn:se:umu:diva-109971OAI: oai:DiVA.org:umu-109971DiVA: diva2:859928
The XXVII International Population Conference, Busan, Korea, 26-31 August 2013.
FunderSwedish Research Council, 349-2008-6592
This paper is addressing the modelling of old age mortality and its dependence of factors earlier in life. We argue for alternatives to the widely used proportional hazards (PH) model, especially Cox regression. There are several reasons for this. First, it is well known that old age mortality very often is well described by the Gompertz distribution. Second, accelerated failure time (AFT) models can be expressed as linear models, which is important when interest lies in the analysis of mediating effects in the analysis of the impact of early-life factors on old-age mortality. Third, the results of an AFT model fit is easier and more intuitive to interpret in tems of years lost or gained, compared to the PH model fit which reports relative risks. Fourth, contrary to "common knowledge", the family of Gompertz distributions is both a collection of PH families and a collection of AFT families, which we demonstrate in the paper. For instance, Kleinbaum and Klein (2005), in their text book on survival analysis, writes: "The Gompertz model is a parametric PH model but not an AFT model". This mistake is reiterated by other authors.2015-10-092015-10-092016-06-08