Donamix, the user data is actually stored in the above mentioned table.
If you are talking about the method which takes those values from the database, you can look at user lists example. There is age and sex is indicated under user thumbnails.
So you can take a look here: ow_systems_plugins/base/controllers/user_list.php
public function getFields( $userIdList )
If it is not what you're looking for, please provide more details what you're doing and how to you want to achieve this.
Thanks for the explanation Ross as to what function to use.