Table 1.

The population-based postal survey questionnaire (Q1)

Measure	Measurement scale
Demographic variables
Gender	Female/male
Age	Birth year
Marital status	Married, cohabitating/Separated, divorced/Widowed/single
Body height	Centimetres
Body weight	Kilograms
Employment status	Working full time/working part time/not working/student/working full time in the home/unemployed or seeking work/age retired/disability pension/sick leave
Education	Lower secondary school/ Higher secondary school/University 1-4 years/University >4 years
Lifestyle variables
Frequency of leisure time physical activity [67]	Never/Less than once a week/Once a week/2-3 times a week/Almost every day
Intensity of leisure time physical activity [67]	I take it easy without breaking into sweat or losing my breath/I push myself so hard that I lose my breath and break into a sweat/I push myself to near-exhaustion
Duration of leisure time physical activity [67]	Less than 15 minutes/16-30 minutes/30 minutes-1 hour/More than 1 hour
Daily smoking	Yes/no
Musculoskeletal pain and symptoms
Standardised Nordic Questionnaire (SNQ) Pain in past year [68]	Body manikin showing 10 body parts: Yes/No
SNQ Pain affected daily activities [68]	Body manikin showing 10 body parts: Yes/No
SNQ Pain in past 7 days [68]	Body manikin showing 10 body parts: Yes/No
Average musculoskeletal pain past 7 days	NRS: 0-10
Osteoarthritis diagnosis	‘Have you ever been diagnosed with osteoarthritis in hip/knee/hand by a medical doctor and/or x-ray?’ Response categories include: Yes, hip/ Yes, knee/ Yes, hand/ No.
Most troublesome OA joint	Knee/Hip/Hand
Health, comorbidity, and subjective health complaints
General health nowadays	Poor/Not so good/Good/Very Good
Heart disease	Yes/No
Lung disease	Yes/No
Cancer	Yes/No
Diabetes	Yes/No
Osteoporosis	Yes/No
Irregular heartbeat	Yes/No
Chest pain	Yes/No
Breathing difficulties	Yes/No
Gastrointestinal symptoms	Yes/No
Skin problems	Yes/No
Tiredness/fatigue	Yes/No
Dizziness	Yes/No
Anxiety	Yes/No
Depression	Yes/No
Health care utilization
Medical doctor	Number of visits past year
Medical specialist	Number of visits past year
Physiotherapist	Number of visits past year
Chiropractor	Number of visits past year
Occupational therapist	Number of visits past year
Home nurse	Number of visits past year
Alternative therapy	Number of visits past year
Hospital admissions	Number of days past year
Medication use
Glucosamine	Yes, daily/Yes, sometimes/No
Paracetamol	Yes, daily/Yes, sometimes/No
Anti-inflammatory medication	Yes, daily/Yes, sometimes/No
Use this medication due to musculoskeletal pain	Yes, daily/Yes, sometimes/No/Do not know
Functional ability
10-ADL Multidimensional Health Assessment Questionnaire (MDHAQ) [69]	0-40; Without any difficulty/With some difficulty/With much difficulty/Unable to do
COOP/WONCA Physical fitness [70]	Very heavy activity/Heavy /Moderate/ Light/Very light
COOP/WONCA Feelings [70]	Not at all/Slightly/Moderately/Quite a bit/Extremely
COOP/WONCA Daily activities [70]	No difficulty at all/A little bit of difficulty/Some difficulty/Much difficulty/Could not do
COOP/WONCA Social activities [70]	Not at all/Slightly/Moderately/Quite a bit/Extremely