Morbidity and Mortality in England, 1850-1950: Testing the Insult Accumulation and Constant "Frailty" Hypotheses

Andy Hinde, University of Southampton
Aravinda Guntupalli, University of Southampton
Bernard J. Harris, University of Southampton
Martin Gorsky, London School of Hygiene and Tropical Medicine (LSHTM)

This paper analyses the relationship between morbidity and mortality in England during the late-19th and early-20th centuries using a sample of more than 5,000 individual sickness histories drawn from the records of the Hampshire Friendly Society. The focus of the analysis is on testing the constant “frailty” and insult accumulation hypotheses proposed by Alter and Riley (1989). The analysis examines the impact of duration and frequency of sickness at ages under 50 on mortality at ages over 50, comparing: (1) a model incorporating a constant “frailty” term, (2) a model including sickness history data to examine the effects of insult accumulation, and (3) a model encompassing both models (1) and (2). A multiple state competing risks model is then used to assess the impact of insult accumulation and frailty on the hazards of falling sick and recovering from sickness, treating death as a competing risk in both cases.