Change in number of pain sites - which factors are important? A 12-year prospective cohort study

Abstract

BackgroundPain in multiple body sites is common and often persistent. The purpose of this prospective study was to examine the change in the number of pain sites (NPS) over time and to evaluate to which extent clinical, demographic, lifestyle and health-related factors predict a change in NPS.MethodsThis was a population-based longitudinal cohort study of adults (n = 2,357). Data on pain, demographic, lifestyle, and health-related variables were collected by questionnaires in 2008 and 2020 and register data from 2006 to 2017. Data was analysed with linear regression.ResultsWe found a mean decrease in NPS over the 12-year follow-up period (-0.36 (95% CI; -0.44; -0.27) and 56% of this sample reported no change or only one pain site increase/decrease over 12 years. While participants reporting pain for less than 3 months at baseline had almost no change in NPS (-0.04 (95% CI; -0.18; 0.10)), participants with pain for longer than 3 months decreased by -0.51 (95% CI; -0.62; -0.41). Age at baseline (20–49 years), pain intensity, and obesity (BMI ≥ 30) were associated with an increase in NPS over the follow-up period.ConclusionsNPS is relatively stable over time. We found a small mean decrease in NPS over 12 years varying between participants with pain for longer than 3 months and pain for less than 3 months respectively. The results also indicate that pain intensity, age, and obesity could be relevant factors to consider when predicting change in NPS.