Fig. 1

Definition of musculoskeletal pain. Definition of considerable musculoskeletal pain, based on the combination of the frequency and the intensity of reported complaints during the preceding year. A subject was considered to have pain (denoted by dark grey boxes) if reporting complaints at least “seldom” with an intensity of at least seven (very severe), or “sometimes” with an intensity of at least three (moderate), or “often” or “very often” with an intensity of at least two (slight/mild)