Latitude, sun exposure and vitamin D supplementation: associations with quality of life and disease outcomes in a large international cohort of people with multiple sclerosis

Abstract

BACKGROUND: A growing evidence base implicates vitamin D, sun exposure and latitude in the aetiology of multiple sclerosis (MS), however there are less data on the associations of these variables with disease outcomes. METHODS: We undertook a cross-sectional survey of over 2000 people with MS recruited through internet platforms, seeking self-reported data on geographical location, intentional sun exposure for health, and supplementation with vitamin D, among other lifestyle variables. We also requested data on health-related quality of life (MSQOL-54), self-reported doctor-diagnosed relapse rate, and disability (Patient Determined Disease Steps). Bivariate and multivariate analyses were use..