Does birth weight or preterm birth predict worse pain prognosis in adulthood? A Northern Finland Birth Cohort Study followed up to 46 years of age.

Although pain is a highly common symptom, only a subset of individuals develops chronic and disabling conditions. Delving into the predictors for poor musculoskeletal pain (MSK) outcomes in adulthood may help identify those needing early prevention and intervention. This study aimed to evaluate whether birth weight or preterm birth predicts worse prognosis of MSK pain in adulthood. Participants in the Northern Finland Birth Cohort 1966 were followed from birth to 46 years of age. Associations of birth weight (measured using corrections to gestational age) and preterm birth (<37 completed weeks) with high-risk classification for worse pain using three prognostic tools: the Örebro Musculoskeletal Pain Screening Questionnaire-Short Form (ÖMPSQ-SF), STartT Back Tool (SBT), and Risk of Pain Spreading (ROPS) assessed at 46 years among people reporting MSK pain (n=3,200-4,525). Log-binomial regression models for dummy outcomes (ÖMPSQ-SF and SBT) and generalized linear regression models for continuous outcomes (ROPS) were employed. Birth weight did not predict high-risk classification by any tool. Compared to full-term participants, those born preterm had higher risk of being classified into the high-risk group only according to ÖMPSQ-SF (relative risk 1.61, 95% confidence interval 1.00-2.59) and SBT (1.61, 1.14-2.28). Adjustments did not change these results. Preterm birth appeared to predict allocation to the group with poorer prognosis of MSK outcomes as measured by ÖMPSQ-SF and SBT, but not by ROPS. This highlights the need for further research into the role of preterm birth in the development or accumulation of adverse pain-related thoughts and experiences in mid-life. PERSPECTIVE: Preterm birth tended to predict allocation to the high-risk group for worse pain prognosis in adulthood. Similar was not observed concerning birth weight. Further research is warranted to validate the results and delve into explanatory pathways.