Background Research suggests that the onset of musculoskeletal pain and its evolution into a chronic condition is related to adverse psychosocial contexts throughout the life course. However, the specific individual socioeconomic characteristics and psychological traits which may determine the onset of chronic musculoskeletal pain remain unclear, particularly since most studies are performed in middle-aged adults where chronic pain is already well-established and may itself be a cause of psychosocial status.

Objectives To estimate the associations between individual psychosocial factors and chronic musculoskeletal pain in a population-based cohort of 21-year-old adults.

Methods The EPITeen cohort of adolescents born in 1990 was assembled during the 2003/2004 school year in schools in Porto (Portugal). The 21 years old follow-up is ongoing since August 2011. Data on socioeconomic characteristics (sex, education, family income, social class and occupational status), smoking and alcohol drinking behaviours, and severity of fatigue and trouble thinking or remembering in the previous week were collected by face-to-face interview. Severity of depressive symptoms in the previous two weeks was evaluated by self-report using the Beck Depression Inventory-II. Musculoskeletal regional pain (neck, shoulders, elbows, wrists/hands, upper back, lower back, hips/thighs/buttocks, knees and ankles/feet) was assessed using the Nordic Musculoskeletal Questionnaire. Pain chronicity was defined as having had recurrent and/or persistent pain during at least three months.

In order to estimate the association between socioeconomic, lifestyles and psychological characteristics and chronic musculoskeletal pain, odds ratios (OR) and the corresponding 95% confidence intervals (95%CI) were calculated using logistic regression.

Results From the 1435 participants (52.4% women) evaluated, 20.8% (n=298) reported at least one anatomical region with recurrent and/or persistent pain during at least three months in the previous 12 months. Intermediate family income decreased the risk of chronic musculoskeletal pain when compared to lower family income (OR_{1001€-2000€}=0.67; 95%CI: 0.47, 0.94; OR_{2001€-3000€}=0.59: 95%CI: 0.39, 0.88). Unemployed participants and full-time students had lower risk of chronic musculoskeletal pain when compared to those employed (OR_unemployed=0.58; 95%CI: 0.37, 0.90; OR_student=0.60; 95%CI: 0.44, 0.81). Fatigue, trouble thinking or remembering and BDI-II score (depressive symptoms) were positively associated to chronic musculoskeletal regional pain (OR_fatigue=1.41; 95%CI: 1.08, 1.84; OR_trouble=1.34; 95%CI: 1.04, 1.74; OR_BDI-II=1.04; 95%CI: 1.02, 1.06, respectively). Nevertheless, sex, education, social class perception and smoking and drinking behaviours at 21 years of age were not significantly associated to chronic musculoskeletal pain report.

Conclusions Psychosocial contexts characterized by low family income, working early in life, reporting fatigue and problems thinking or remembering or having depressive symptoms seem to be associated to chronic musculoskeletal pain in young adults. These findings suggest that the inclusion of psychosocial aspects in chronic pain prevention strategies may be more efficient, particularly if operated early in life.

Disclosure of Interest None Declared