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 Fatigue Syndrome (CDC)
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 (PROMIS)
26. Fatigue (CIS)
27. Fever
28. General health (PROMIS)
29. Insomnia
30. Kidney & bladder diseases
31. Mental illnesses
32. Musculoskeletal conditions
33. Musculoskeletal symptoms
34. Musculoskeletal pain (WPI)
35. Neurological disorders
36. Occupational eczema (NOSQ)
37. Oral cavity conditions
38. Ostheoarthritis (WOMAC)
39. Reproductive organ diseases
40. Respiratory diseases
41. Respiratory problems (general)
42. Respiratory problems (ELON)
43. Sinusitis
44. Skin conditions
45. STDs
46. Symptoms (SCL-90)
47. Throat conditions
48. Upper extremities (UEFS)