Comorbidity among multiple pain symptoms and anxious depression in a Dutch population sample

Most studies on pain focus on specific disorders, which makes it difficult to compare characteristics across different types of pain symptoms. In this large population-based study, we examine the prevalence and comorbidity patterns among pain symptoms across a wide range of anatomic sites (back, neck, head, abdomen, joints, chest, face, teeth, and "other") in relation to anxious depression and a range of demographic, health, and lifestyle variables. Self-report data were collected in 11,787 adult participants of The Netherlands Twin Registry (mean age 44.5 years, 62% female), including twins and relatives of twins. Headache and abdominal pain were strongly associated with female sex, whereas chest pain and toothache were not. Joint pain strongly increased with age, whereas headache and abdominal pain decreased with age. Most other pain sites were only weakly associated with age. A highly consistent pattern of comorbidity was observed: All pain symptoms were correlated with all other pain symptoms, as well as with anxious depression. Frequent and widespread pain (ie, pain at multiple sites) was most strongly associated with anxious depression. These observations reflect important differences between specific pain symptoms, suggesting partly separate etiologies, but also highlight the importance of shared mechanisms underlying pain symptoms in general.

The association of pain with sex and age strongly depends on pain location. However, all pain sites are consistently associated with other pain sites as well as with anxious depression. This provides important clues with respect to both similarities and differences in the mechanisms underlying different types of pain.