Adult and elderly Lifelines participants participating in second assessment 2A received two questionnaires, 2A Questionnaire 1 and 2A Questionnaire 2.
2A Q2 was followed by 2A Visit 2, on average within xx days (+/- yy days).
2A Q2 was followed up by assessment 2B, on average within xx months (+/1 yy months).
2A Q2 is procedurally equivalent to 1A Questionnaire 2 and 3A Questionnaire 2.
The average time between 1A Questionnaire 2 and 2A Q2 was xx months (+/- yy months).

Of all participants that filled out 2A Q2 (n = ~90,000), 30% of participants filled in a paper variant whereas 70% filled in a digital variant.

2A Q2 contained the following sections and subsections:

• Personal data

• Allergies
• Chronic Fatigue Syndrome (CDC)
• Functional bowel symptoms (Rome)
• Eye conditions
• Fatigue (general)
• Fatigue (CIS)
• Musculoskeletal symptoms
• Musculoskeletal pain (WPI)
• Respiratory problems (ELON)

• Drug use
• Informal care
• Smoking & tobacco use

• Alcohol use (FFQ)

• Scalp hair