The health-related quality of life was measured using the validated Finnish version of the RAND 36-Item Health Survey 1.0 (RAND-36). The 36-item self-report instrument consists of eight separate scales of quality of life: (1) physical functioning (10 items), (2) physical role functioning (four items), (3) emotional role functioning (three items), (4) social role functioning (two items), (5) bodily pain (two items), (6) mental health (five items), (7) energy (four items) and (8) general health (five items). The scores were calculated in a two-step process using the instructions provided by Ware et al. (1994) in the user´s manual. First, all items were scored on a scale from 0 to 100. A higher score defines a better health or function. Second, items in the same scale were averaged together to create the eight scale scores. Scale scores represented the average for all items in the scale.