Abstract

The sustained increase in longevity initiated during the second half of the 20th Century poses huge challenges upon the public and private healthcare and pensions' systems. Current theories do not explain the observed phenomenon, what precludes predictions of its future trends. The authors goal was to go back to Omram's original project—to develop an epidemiologic theory of the demographic change—but looking for an explanation alternative to the epidemiologic transition proposed by him. The study expands upon a previous one, that showed, for the first time, a cohort association between the mortality burden of 1918 Influenza Pandemic and the 20th Century rise in CHD mortality. Based on an age-period-cohort analysis of USA and UK mortality (and natality) data (1933–2005) and on the epidemiology of influenza as we know it, it is shown that, overall, temporal changes in mortality and natality accompany the recycling of influenza A viruses, that is, the re-exposure of human populations, from time to time, to influenza A subtypes that circulated in the past. Mortality (and natality) and main causes of death change as birth cohorts (whole population and maternal) primed at early life with one (period-specific) influenza A sub-type, course through subsequent influenza A environments over time.1 The implications of this new theory to demography and to the epidemiology of several diseases are revolutionary.