Lifelines includes predominantly health-related variables. A large portion of those variables are aimed to assess whether participants have particular diseases and/or (undiagnosed) symptoms, via self-report questionnaires.
Variables that more neutrally assess the (measured and/or self-reported) physical characteristics of participants, independent of specific diseases and symptoms, can be found here.

In Lifelines, variables in this section are organized in the following subsections:

1. Acne
2. Adrenal gland disorders
3. Allergies
4. Asthma & allergies (ISAAC)
5. Blood disorders
6. Bronchial Hyperresponsiveness (BHQ)
7. Cancer
8. Cardiovascular diseases
9. Cardiovascular symptoms
10. Chronic diseases (Covid-19)
11. Cold/Flu
12. Connective Tissue Disease (CSQ)
13. Covid-19 infection
14. Diabetes
15. Digestive system diseases
16. Digestive symptoms
17. Functional bowel symptoms (Rome III)
18. Diseases (other)
19. Diseases (PROMAS)
20. Ear conditions
21. Eye conditions (general)
22. Eye conditions (OQ)
23. Eating disorders
24. Fatigue (general)
25. Fatigue (CDC)
26. Fatigue (PROMIS)
27. Fatigue (CIS)
28. Fever
29. General health (PROMIS)
30. Insomnia
31. Kidney & bladder diseases
32. Menopausal Symptoms (GCS)
33. Mental illnesses
34. Musculoskeletal conditions
35. Musculoskeletal symptoms
36. Musculoskeletal pain (WPI)
37. Neurological disorders
38. Occupational eczema (NOSQ)
39. Oral cavity conditions
40. Ostheoarthritis (WOMAC)
41. Reproductive organ diseases
42. Respiratory diseases
43. Respiratory problems (general)
44. Respiratory problems (ELON)
45. Skin conditions
46. STDs
47. Symptoms (Covid-19)
48. Symptoms (SCL-90)
49. Throat conditions
50. Upper extremities (UEFS)