A not so happy day after all: excess death rates on birthdays in the U.S.

This study estimates average excess death rates on and around birthdays, and explores differences between birthdays falling on weekends and birthdays falling on weekdays. Using records from the U.S. Social Security Administration for 25 million people who died during the period from 1998 to 2011, average excess death rates are estimated controlling for seasonality of births and deaths. The average excess death rate on birthdays is 6.7% (p < 0.0001). No evidence is found of dips in average excess death rates in a ±10 day neighborhood around birthdays that could offset the spikes on birthdays. Significant differences are found between age groups and between weekend and weekday birthdays. Younger people have greater average excess death rates on birthdays, reaching up to 25.4% (p < 0.0001) for ages 20-29. Younger people also show the largest differences between average excess death rates on weekend birthdays and weekday birthdays, reaching up to 64.5 percentage points (p = 0.0063) for ages 1-9. Over the 13-year period analyzed, the estimated excess deaths on birthdays are 4590.