Longevity and month of birth: evidence from Austria and Denmark.

This study investigates the relationship between month of birth and life span. It uses 2 different data for total populations in Austria and Denmark. The Austrian data are based on vital statistics of the exact data of birth and the exact date of death for each person dying after age 50 between 1988 and 1996. The Danish data consist of the total population aged 50+ on April 1, 1968. These people were then followed until their death or until August 1998. Results suggest that life span and month of birth were in fact related. Evidences were presented to support or argue the three hypotheses being tested that explain the relationship between month of birth and longevity. Overall, many studies support that this pattern was not the result of the seasonal distribution of death. And the longevity cannot be explained by the so-called ¿birthday-effect¿--the alleged tendency of people to die shortly after their birthday. Instead, the study concluded by discussing the possible social and biological mechanisms related to a person's season of birth that might influence life expectancy.