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 secondary section and/or subsection to facilitate the findability of the variable in the online data catalogue. Furthermore, note that some variable names have been changed over time after internal delibaration or on request of researchers.