Shift work influences multiple sclerosis risk.
Hedström AK, Åkerstedt T, Olsson T et al.
Karolinska Institutet, Stockholm, Sweden.
Mult Scler 2015;21:1195–9.
Melinda Magyari’s review: A previous study from the Swedish authors of this article suggested that there is an association between shift work at a young age and the risk of multiple sclerosis (MS; Ann Neurol 2011;70:733–41). The current article confirms that shift work before the age of 20 years is a risk factor for MS, although the risk is small.
This population-based, case–control study involved a retrospectively collected survey database, the Epidemiological Investigation of MS (EIMS), which has previously been used for the investigation of lifestyle factors and environmental exposures in MS. Information on 2337 incident cases and 4904 controls, recruited via 40 study centers including all of the university hospitals in Sweden, was collected from April 2005 to December 2013. Shift work was defined as a permanent or an alternating pattern of working hours other than ordinary day work, including night work, morning work before 7 am, or evening work after 9 pm.