A strong association between non-musculoskeletal symptoms and musculoskeletal pain symptoms: results from a population study

BACKGROUND: There is a lack of knowledge about the pattern of symptom reporting in the general population as most research focuses on specific diseases or symptoms. The number of musculoskeletal pain sites is a strong predictor for disability pensioning and, hence, is considered to be an important dimension in symptom reporting. The simple method of counting symptoms might also be applicable to non-musculoskeletal symptoms, rendering further dimensions in describing individual and public health. In a general population, we aimed to explore the association between self-reported non-musculoskeletal symptoms and the number of pain sites. METHODS: With a cross-sectional design, the Standardised Nordic Questionnaire and the Subjective Health Complaints Inventory were used to record pain at ten different body sites and 13 non-musculoskeletal symptoms, respectively, among seven age groups in Ullensaker, Norway (n = 3,227). RESULTS: Results showed a strong, almost linear relationship between the number of non-musculoskeletal symptoms and the number of pain sites (r = 0.55). The number and type of non-musculoskeletal symptoms had an almost equal explanatory power in the number of pain sites reported (27.1% vs. 28.2%). CONCLUSION: The linear association between the number of non-musculoskeletal and musculoskeletal symptoms might indicate that the symptoms share common characteristics and even common underlying causal factors. The total burden of symptoms as determined by the number of symptoms reported might be an interesting generic indicator of health and well-being, as well as present and future functioning. Research on symptom reporting might also be an alternative pathway to describe and, possibly, understand the medically unexplained multisymptom conditions.