# Is there really no participant birth year data?

Since data freeze 11 (DF11) there is APPROX\_BIRTH\_DATE variable in the [minimum extended phenotype data](https://docs.finngen.fi/finngen-data-specifics/red-library-data-individual-level-data/what-phenotype-files-are-available-in-sandbox-1/minumum-extended-phenotype-data) file.

This variable does not exist in earlier data freezes, but you can calculate birth year easily from all individuals using longitudinal data. Each event has the APROX\_EVENT\_DAY and EVENT\_AGE, so by computing `APROX_EVENT_DAY - EVENT_AGE` you should be able to get birth year from any of your desired endpoints.