[Mortality and birthdays]

Abstract

The authors study the date of death in relationship, in the annual cycle, to date of birth of every person who died of natural causes in Switzerland between 1st January, 1969 and 31st December, 1992 (N = 12,275,033). They highlight a maximal mortality (17% over expected) on the actual anniversary of birth with the entire population, a slightly lower figure being found under 80 years of age, higher over this age. They tie this phenomenon to the classical group of "anniversary reactions", in which problems of identity probably play a role. An uncertainty hangs nevertheless over the value of these findings, which are not confirmed by any published material, and even denied by some.