EIMS is an acronym for Epidemiological Investigation of Multiple Sclerosis. The study is part of a collaboration between the Department of Cardiovascular Epidemiology at the Institute of Environmental Medicin and the Institute of Clinical Neuroscience at the Center for Molecular Medicine, both at Karolinska Insitutet. The aim of the study is to investigate the causes of why some individuals develop the disease multiple sclerosis (MS), thereby increasing the knowledge of the biological processes involved and identifying factors which may affect the prognosis of the disease.

Our understanding of the causes of MS has increased immensely since the EIMS study was initiated in 2004. The unique study design used in the EIMS study has led to an increase in the knowledge of how hereditary factors and our environment affect the risk of developing MS. EIMS is, to date, the largest Swedish case-control study on newly diagnosed MS patients.

A case-control study is a study where cases (MS patients) are matched with controls (randomly selected individuals from the population who do not have MS) of the same age, gender and residential area. The genetics, lifestyle factors and environmental factors are thereafter compared between the cases and controls to identify factors which may increase or decrease the risk of developing the disease. This study design is well suited to the study of rare diseases, such as MS, since a population size which allows for statistically significant results can be obtained in a relatively short amount of time. 

The EIMS study is unique in its collaborative structure where 42 neurological clinics representing all the Swedish counties work together to recruit patients into the study.  Included cases are newly diagnosed MS patients or patients with possible MS between the ages of 15 and 70 who comprehend the Swedish language. For each case, two randomly selected controls from the Swedish population are identified using a search engine created by Statistics Sweden. The cases are matched to the control by age, gender and residential area. The controls are asked to complete the same questionnaire on lifestyle factors as the cases and are thereafter asked to give a blood sample. Data has so far been collected on over 2,000 cases and twice as many controls. The response rates for the questionnaire are exceptionally high for both cases and controls; 91% and 70% respectively.  

The questionnaire contains questions covering a broad span of factors such as smoking habits, alcohol intake, physical activity questions, family disease history, work environments, parity and more. The broad coverage within the questionnaire allows researchers to assess many different aspects within a person’s life to more readily uncover the mysteries behind which factors cause MS.

The EIMS study is constantly evolving to adapt to new ideas and the latest research results within the study of MS. The questionnaire is continuously reviewed and updated to meet new research demands to be able to further investigate impending hypotheses.

We are extremely grateful to all the cases and controls who take the time to complete our comprehensive questionnaire and give blood samples so that the research on MS may continue to progress.

To learn more about how the EIMS study is conducted click here!