Multiple sclerosis - the impact of environmental- and lifestyle factors

Multiple sclerosis is a chronic inflammatory disease of the central nervous system (CNS) that mainly affects young adults between 20 and 40 years of age. The cause of the disease is not yet known, but it is probably a result of a complex interaction between genetic and environmental factors. Many environmental and lifestyle factors influence the risk of developing MS, among others overweight and smoking. These factors potentially also affect disease progression, although this is an area with a lot of unanswered questions. 

We studied how tobacco use, overweight (BMI) and to fatty hormones (leptin and adiponectin) affected disease activity in MS among 86 – 88 Norwegian patients with MS. The patients included originally were participants in a randomized study (the OFAMS-Study) and were followed up over a period of 2 years, 6 months without treatment and 18 months with interferon-beta treatment. Disease activity and -progression were measured by patients experiencing new relapses, progression of the Expanded Disability Status Scale (EDSS) or new brain lesions on MRI. 

In this thesis, no correlation was found between tobacco use and disease activity. This suggests that smoking affects the disease more through degenerative mechanisms than through inflammation. Less of the overweight patients reached NEDA (no evidence of disease activity) on interferon-beta treatment than patients with weight in the normal range. No association between levels of leptin and adiponectin in the blood and disease activity or treatment response in multiple sclerosis was found. These findings may be caused by Interferon-beta not being dose-adjusted to weight and indicate that one should strive to have a more individually tailored and weight adjusted treatment of MS. Our findings also show that the lipid hormones leptin and adiponectin do not have a potential as biomarkers in MS. 

This thesis expands the basis of knowledge on how environmental- and lifestyle factors affect disease progression and treatment of MS.

Silje Stokke Kvistad (b. 1980) studied at the University of Bergen and achieved the medical degree in 2007. She works at the Department of Immunology and Transfusion Medicine and is part of the Norwegian Multiple Sclerosis Competence Center and Research Group. The thesis is written at the Department of Clinical Medicine at the University of Bergen, with prof. Øivind Torkildsen as main supervisor and prof. Kjell-Morten Myhr as co-supervisor.