Related Experiment Video
Updated: Jul 13, 2026

A Method of Trigonometric Modelling of Seasonal Variation Demonstrated with Multiple Sclerosis Relapse Data
Published on: December 9, 2015
[Meteorological variables do not explain the North-South gradient in mortality from multiple sclerosis in Spain]
Paula Guerrero-Alonso1, Dolores Prieto-Salceda, Javier Llorca
1Preventiva y Salud Pública, Facultad de Medicina, Universidad de Cantabria, Santander, España.
Objectives:
To determine whether weather conditions explain the North-South gradient in multiple sclerosis (MS) mortality described in Spain.
Methods:
The age-adjusted MS mortality rate by Spanish provinces from 1975 to 1998 was correlated with several climatic variables.
Results:
MS mortality was negatively correlated with minimum, average and maximum temperatures, the mean number of hours of sunshine, and the mean number of sunny days. A positive correlation was found with the average amount of rain. Most correlations disappeared after adjusting by latitude. However, MS mortality was associated with latitude after adjusting by climatic factors.
Conclusions:
The North-South gradient in MS mortality in Spain cannot be fully explained by weather differences. Therefore, other hypotheses are required to explain this association.
Related Concept Videos
Multiple Sclerosis l: Introduction
Bias in Epidemiological Studies
Confounding in Epidemiological Studies
Factors Affecting Body Temperature
Factors may include:
Causality in Epidemiology
Regression Toward the Mean