Left nucleus accumbens volume is associated with poor sleep in hip osteoarthritis.

Objective: Reduction in the volume of the nucleus accumbens (NAc) has emerged as a promising signature of chronic pain transition, including in osteoarthritis (OA). Yet, less is known about the factors that could influence these changes in the mesolimbic system. Given that poor sleep is common in OA, and recent studies of sleep disturbance on pain perception in animals and healthy populations have specifically implicated the NAc, we hypothesised that the left NAc volume in hip OA would be associated with sleep quality and quantity. Furthermore, we explored how sex interacts with this relationship. Methods: Cross-sectional study in participants with hip OA (n = 34; aged 60+/-12 years, 67 % females) who reported moderate pain were recruited. Results: A one-sample Conclusions: Our results suggest that the reduction of the NAc volumes as a candidate biomarker of pain might be influenced by sleep. This exploratory finding in a chronic hip OA population is consistent with the results previously only reported in animal and experimental pain/sleep studies in healthy participants. Significance: The left NAc as a candidate biomarker of chronic pain is sensitive to the effects of sleep quality, especially in females with OA.