Injury preceding the classical recognition of multiple sclerosis: A population-based study.

BACKGROUND

We investigated the association between multiple sclerosis (MS) and fractures, dislocations/sprains/strains, and burns preceding MS recognition.

METHODS

We conducted a cohort study using clinical and population-based health administrative data in British Columbia, Canada (1991-2020). We compared the risk of a fracture, dislocation/sprain/strain, and burn in the six years preceding an MS cases' first demyelinating claim (administrative cohort=9197) or MS symptom onset (clinical cohort=1446) to that of matched general population controls using modified Poisson regression. As sensitivity analyses, we used high-dimensional propensity scores (hdPS) to address residual confounding and targeted maximum likelihood estimation (TMLE) for mis-specification.

RESULTS

In the six years before the first demyelinating claim (administrative cohort), the risk of a fracture (adjusted relative risks [adjRR]=1.28;95 %CI:1.20-1.36), dislocation/sprain/strain (adjRR=1.20;95 %CI:1.15-1.23), and burn (adjRR=1.40;95 %CI:1.22-1.62) was higher among MS cases. After hdPS adjustment and TMLE, the adjusted relative risks decreased slightly: fracture (hdPS=1.20; TMLE=1.20), dislocation/sprain/strain (hdPS=1.15; TMLE=1.15), and burn (hdPS=1.25; TMLE=1.26). Pre-MS symptom onset (clinical cohort), the associations were weaker but in the same direction.

CONCLUSION

Fractures, dislocations/sprains/strains, and burns were more common among people with MS before its classical recognition, suggesting that MS could be detected earlier.