There is a need of knowledge on risk factors and underlying mechanisms of persistent MSK pain in adolescence to increase our understanding and facilitate preventative strategies.~OBJECTIVE:~The aims of this prospective cohort study are to investigate whether health complaints and an accumulation of health complaints in adolescence, are associated with the incidence of persistent MSK pain two years later.~METHODS:~This will be a prospective study using data from the Fit Futures study conducted in the northern Norway. Adolescents (15-19 years) were recruited to the first survey (Fit Futures 1, FF1) in 2010/2011, and followed up to years later (Fit Futures 2, FF2). Data was collected through a comprehensive questionnaire and physical tests.~The exposures will be common health complaints in adolescence measured in FF1, including self-reported asthma, allergic rhinitis, atopic eczema, abdominal pain, headache and psychological distress (Hopkins Symptom Checklist).~Potential confounders will include age, sex and parents' socioeconomic status.~Statistical analyses:~Histograms and QQ-plots will be used to investigate the distribution of data. Normally distributed data will be presented with means and standard deviations (SD), while median and range will be used to present skewed data. Categorical data will be presented as counts and percentages. Missing data in exposures and confounders will be considered handled with multiple imputation. Participants with missing data on outcome will be excluded from the analyses. Baseline characteristics of adolescents lost to follow-up or with incomplete outcome data in FF2 will be compared to baseline characteristics of respondents.~A two-year incidence rate of persistent MSK pain will be presented.~Logistic regression analyses, providing odds ratios (ORs) with 95% confidence intervals (CI), will be used to investigate the association between health complaints (measured in FF1) and later persistent MSK pain (measured in FF2). The association between health complaints and persistent MSK pain will first be investigated separately for each complaint (asthma, allergic rhinitis, atopic eczema, psychological distress, headache and abdominal pain), secondly as the number of health complaints regardless of type (using an ordinal count variable). All logistic regression analyses will be conducted as crude and adjusted analyses. Statistical analyses will be conducted with STATA statistical software system.
Persistent musculoskeletal (MSK) pain in adolescence is associated with disability, absence from school and reduced quality of life. We know little about risk factors and underlying mechanisms of persistent MSK pain in this age group. For example, the effect of other health complaints on the development of persistent MSK pain is scarcely investigated. In this prospective cohort study, data from the Fit Futures study on Norwegian adolescents (15-19 years old) will be used to investigate whether health complaints and an accumulation of health complaints in adolescence are associated with the incidence of persistent MSK pain two years later.