Body Size and the Risk of Multiple Sclerosis in Norway and Italy: The EnvIMS Study

Mult Scler. 2015 Apr;21(4):388-95. doi: 10.1177/1352458514546785. Epub 2014 Sep 2.

Abstract

Background: Obesity may be a risk factor for developing multiple sclerosis (MS).

Objective: We examined if body size influences the risk of MS in a population-based, case control study.

Methods: A total of 953 cases and 1717 controls from Norway and 707 cases and 1333 controls from Italy reported their body size by choosing a silhouette 1 to 9 (largest) every fifth year from age 5 to 30 and at time of study. The body size-related MS risk was defined by odds ratios (ORs) in logistic regression analyses adjusting for age, smoking and outdoor activity.

Results: In Norway a large body size (silhouettes 6-9) compared to silhouette 3 increased the risk of MS, especially at age 25 (OR 2.21; 95% CI 1.09-4.46 for men and OR 1.43; 95% CI 0.90-2.27 for women). When comparing silhouette 9 to 1, we found a significant dose-response from age 10 until age 30 peaking at age 25 (sex-adjusted OR 2.83; 95% CI 1.68-4.78). The association was present for at least 15 years prior to disease onset. No significant associations were found in Italy.

Conclusions: Obesity from childhood until young adulthood is a likely risk factor for MS with a seemingly stronger effect in Norway than in Italy.

Keywords: Multiple sclerosis; body mass index; body size; case control studies; epidemiology; obesity; vitamin D.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Body Mass Index
  • Body Size*
  • Case-Control Studies
  • Child
  • Female
  • Humans
  • Italy / epidemiology
  • Male
  • Multiple Sclerosis / epidemiology*
  • Norway / epidemiology
  • Obesity / epidemiology*
  • Odds Ratio
  • Risk Factors
  • Young Adult