Lifelines variables are organized per theme in 13 main sections and ~230 subsections.
The 13 sections are:

1. Children & adolescents
2. Demographics
3. Diseases & Symptoms
4. Elderly (variables that were specifically collected in participants aged 65+ years old)
5. Family health
6. Lifestyle & environment
7. Medical treatment
8. Mental health
9. Nutrition
10. Physical state
11. Reproduction & development
12. Wellbeing & subjective health
13. Secondary & linked variables

Note that some subsections could fall under more than one section (i.e., “alcohol use” could be seen as a subsection of “lifestyle” or of “nutrition”, and “mental illness” could fall under “diseases & symptoms” or “mental health”). Similarly, individual variables may fit in more than one subsection. Lifelines always asigns a primary section and subsection to a variable, but may asign a second, alternative (sub)section to facilitate the findability of the variable in the online data catalogue.

Some Lifelines variables are provided by default in every issued dataset. As a result, these variables are not visible in the data-catalogue. An overview of the default variables can be found here.

Note that we may occasionally change a variable name, if there is a valid reason to do so (i.e. the original name is deemed confusing, too informal, unexpected, inconsistent, or incorrect). You may find a full list of changed variable names following this link: changed variable names.

Seldomly, we find variables that contain mistakes or inconsistencies. Most of the time these mistakes or inconsistencies will be corrected. However, it is possible that some mistakes can either not be corrected, or that correcting them now results in more negative outcomes than positive ones. You may find a full list of unfixable variables following this link: unfixed variables.