Latitude continues to be significantly associated with the prevalence of multiple sclerosis: an updated meta-analysis.

Objectives: Previous studies have demonstrated a strong latitudinal gradient in multiple sclerosis (MS) prevalence. Herein, we present a meta-analysis of the latitudinal gradient of MS prevalence including studies published since our 2011 review, seeking to assess the latitudinal gradient and whether it has changed since our previous analysis.

Methods: Studies published up to December 2018 were located via Embase, Web of Knowledge and PubMed, using standardised search terms; data were extracted from peer-reviewed studies and these studies added to those from our previous analysis.