Shift work in teens linked to increased multiple sclerosis risk

Researchers from Sweden have uncovered an association between shift work and increased risk of multiple sclerosis (MS). Those who engage in off-hour employment before the age of 20 may be at risk for MS due to a disruption in their circadian rhythm and sleep pattern. Findings of this novel study appear today in Annals of Neurology, a journal published by Wiley-Blackwell on behalf of the American Neurological Association and Child Neurology Society.

Previous research has determined that —working during the night or rotating working hours—increases the risk of cardiovascular disease, thyroid disorders, and cancer. Circadian disruption and sleep restriction are associated with working night shifts; these factors are believed to disturb melatonin secretion and increase inflammatory responses, promoting disease states. MS is a central nervous system autoimmune inflammatory disorder that has an important environmental component, thus investigating lifestyle risk factors, such as sleep loss related to shift work, is an important objective and the focus of the current study.

Dr. Anna Karin Hedström and colleagues from the Karolinska Institutet in Stockholm analyzed data from two population-based studies—one with 1343 incident cases of MS and 2900 controls and another with 5129 prevalent MS cases and 4509 controls. The team compared the occurrence of MS among study subjects exposed to shift work at various ages against those who had never been exposed. All study subjects resided in and were between the ages of 16 and 70. Shift work was defined as permanent or alternating working hours between 9 p.m. and 7 a.m.

"Our analysis revealed a significant association between working shift at a young age and occurrence of MS," explains Dr. Hedström. "Given the association was observed in two independent studies strongly supports a true relationship between shift work and disease risk." Results showed that those in the incident MS cohort who had worked off-hour shifts for three years or longer before age 20 had a 2 fold-risk of developing MS compared with those who never worked shifts. Similarly, subjects in the prevalent cohort who engaged in shift work as teens had slightly more than a 2-fold risk of MS than subjects who never worked shifts.

The authors suggest that disruption of circadian rhythm and loss may play a role in the development of MS; however the exact mechanisms behind this increased risk remain unclear and further study is needed.

More information: "Shift Work at Young Age is Associated with Increased Risk for Multiple Sclerosis." Anna Karin Hedström, Torbjörn Åkerstedt, Jan Hillert, Tomas Olsson and Lars Alfredsson. Annals of Neurology; Published Online: October 18, 2011 (DOI:10.1002/ana.22597).

Related Stories

Rotating shift workers have lower levels of serotonin

Aug 01, 2007

People who work rotating shifts have significantly lower levels of serotonin, a hormone and neurotransmitter in the central nervous system believed to play an important role in the regulation of sleep, according to a study ...

Study finds pregnancy safe in multiple sclerosis

Jun 27, 2011

Canadian researchers have found that maternal multiple sclerosis (MS) is generally not associated with adverse delivery outcomes or risk to their offspring. Full findings now appear in Annals of Neurology, a journal publis ...

Young smokers increase risk for multiple sclerosis

Feb 23, 2009

People who start smoking before age 17 may increase their risk for developing multiple sclerosis (MS), according to a study released today that will be presented at the American Academy of Neurology's 61st Annual Meeting ...

Recommended for you

New ALS associated gene identified using innovative strategy

22 hours ago

Using an innovative exome sequencing strategy, a team of international scientists led by John Landers, PhD, at the University of Massachusetts Medical School has shown that TUBA4A, the gene encoding the Tubulin Alpha 4A protein, ...

Can bariatric surgery lead to severe headache?

23 hours ago

Bariatric surgery may be a risk factor for a condition that causes severe headaches, according to a study published in the October 22, 2014, online issue of Neurology, the medical journal of the American Academy of Neurol ...

Bipolar disorder discovery at the nano level

23 hours ago

A nano-sized discovery by Northwestern Medicine scientists helps explain how bipolar disorder affects the brain and could one day lead to new drug therapies to treat the mental illness.

User comments