The genetic causal association between arthritis and low back pain

Arthritis and low back pain (LBP) are prevalent musculoskeletal conditions with a perceived association. Previous observational studies have suggested a possible link between arthritis and LBP, but causality has not been firmly established.

The analysis involved data from a meta-analysis of genome-wide association studies sourced from the UK Biobank Genetics resources on rheumatoid arthritis (RA), osteoarthritis (OA) at any site, knee osteoarthritis (KOA), hip osteoarthritis (HOA), and LBP. Two-sample Mendelian randomization analysis was utilized to evaluate the causal link between arthritis and LBP. The primary method employed was inverse-variance weighting (IVW), with additional techniques such as MR-Egger, weighted median, Cochran Q statistic, and leave-one-out analysis used to identify heterogeneity and pleiotropy.

Genetically determined RA exhibited a causal impact on LBP (Weighted median: odds ratio [OR] = 1.094, 95% confidence interval [CI] 1.002-1.195, p = 0.043). Furthermore, OA at any site and KOA showed causal associations with LBP (Inverse variance weighted: OR = 1.089, 95% CI 1.011-1.173, p = 0.026) and (OR = 1.0004, 95% CI 1.000-1.008, p = 0.019), respectively. Additionally, HOA was also linked causally with an elevated risk of developing LBP (Weighted median: OR = 1.002, 95% CI 1.000-1.004, p = 0.049; Inverse variance weighted: OR = 1.002, 95% CI 1.001-1.004, p = 0.003).

This study offers genetic evidence supporting the causal relationship between RA, OA at any site, KOA, HOA and the increased risk of LBP, especially highlighting the significant impact of HOA.