Acne Genetic Susceptibility Is Linked to Lower Risk of Chronic Low Back Pain

Conflicts of Intertest : No conflicts of interest Sources of Funding : Arthritis UK grant 22467 Background The spine microbiome is a growing area of research and our work and others' investigating the microbiome of intervertebral discs (IVDs) identified Cutibacterium acnes , the bacterium linked to acne, as the most prevalent bacterium in IVDs in patients with chronic low back pain (cLBP). This study aimed to determine whether genetic susceptibility to acne is associated with cLBP and IVD degeneration. Methods A previously developed polygenic risk score (PRS) for acne was validated in the TwinsUK cohort utilising participants who self-assessed their acne status (n = 2091). cLBP was defined as back pain persisting for ≥ 3 months (n = 3572), while IVD degeneration was assessed by MRI scan and quantified using the lumbar disc degeneration summary score (LSUM) (n = 572). Results The acne PRS was validated within TwinsUK, demonstrating it a significant predictor of acne occurrence (OR = 1.82, 95% CI = 1.616 – 2.051, p < 0.001), severe acne requiring medical intervention (OR = 1.58, 95% CI = 1.288 – 1.947, p < 0.001) and therefore a suitable marker of genetic susceptibility to acne. Association testing with cLBP indicated a higher PRS had a significant protective effect (OR = 0.925, 95% CI = 0.859 – 0.997, p = 0.04). Although associated with cLBP, acne PRS was not associated with IVD degeneration positively or negatively (OR = 1.051, 95% CI = 0.968 – 1.141 p = 0.234). Conclusion These findings suggest that genetic susceptibility to acne has a protective effect against cLBP, however this is not associated with reduced IVD degeneration, indicating the involvement of additional biological processes.