Sick Day Patterns Could Be an Early Indicator of MS
Study Funded by the National MS Society Demonstrates Unique Patterns of Sick Leave in People with MS Years Before Disease Onset
Source: National MS Society
Research exploring the multiple sclerosis (MS) prodrome showed that annual sick leave rates are significantly higher up to six years prior to MS onset. The study was funded by the National MS Society and MS Canada.Background: The MS prodrome is an early phase of unspecific signs and symptoms that occur before the first classical signs of MS. The prodrome is difficult to characterize because changes tend to be subtle and difficult to identify. Sickness absence data (i.e., sick days) may be a novel measure for investigating the MS prodrome, as it provides insight into individuals’ general health and wellbeing, which could be valuable for detecting early signs of disease.The Study: Researchers in Sweden reviewed annual sick day rates before MS onset in two groups of people with MS. One group was identified based on MS diagnostic codes and included 8,618 people. The other group was based on people registered in the Swedish MS Registry and included 6,361 people. Each group was compared with about five times the number of controls who were of similar age and sex and had no history of MS. Annual sick day rates were measured for up to 18 years before MS onset and were compared between groups.Results: People with MS had significantly higher annual sick day rates in the years leading up to MS onset or an MS diagnosis. The sick day rate difference was observable six years before MS onset in the group identified by diagnostic codes. The difference was strongest one year prior to MS onset, 2.6 times higher than individuals without MS. In the group using the Swedish MS Registry, a significantly higher rate of annual sick days was observed two years before MS onset. The difference was strongest one year prior to MS onset, 1.2 times higher than individuals without MS.Age- and sex-related differences were also observed, mainly in the year leading up to MS onset. Older individuals and males had higher annual sick day rates.Why Does This Matter? Understanding the MS prodrome could help facilitate improved quality of life and timely diagnosis and treatment intervention for people with MS. Previous studies on the MS prodrome have measured doctors’ visits, hospitalizations, and prescriptions as early markers of disease. Measuring sick days may be another early indicator of disease prior to classical signs of MS and could be a helpful tracking tool. The age- and sex-related differences suggest possible changes in early MS symptoms between groups that affect their ability to work.This study also shows that MS might affect employment early in the course of disease. The National MS Society is here to work with you as you navigate your employment options. Learn more.Learn More…Read about the MS prodrome and research progress on our website.Listen to a discussion about the MS prodrome via the ECTRIMS Podcast or the RealTalk MS Podcast, featuring article author, Dr. Helen Tremlett.“Prodromal phase of multiple sclerosis: evidence from sickness absence patterns before disease onset - a matched cohort study” by Ali Manouchehrinia, Feng Zhu, Jan Hillert, Kyla McKay, Yinshan Zhao, Ruth Ann Marrie, and Helen Tremlett. Published in Journal of Neurology, Neurosurgery, and Psychiatry (2025).
About Multiple Sclerosis
Multiple sclerosis is an unpredictable disease of the central nervous system. Currently there is no cure. Symptoms vary from person to person and may include disabling fatigue, mobility challenges, cognitive changes, and vision issues. An estimated 1 million people live with MS in the United States. Early diagnosis and treatment are critical to minimize disability. Significant progress is being made to achieve a world free of MS.