Insufficient sleep and poor sleep quality during childhood may increase the risk of developing multiple sclerosis (MS) in adulthood, according to study findings published in the Journal of Neurology, Neurosurgery, and Psychiatry.
Shift work has been linked to an increased risk for MS, but the effect of sleep habits on MS risk has not been previously evaluated. For the study, researchers sought to explore the effect of sleep duration, circadian disruption, and sleep quality on MS risk.
The researchers used a Swedish population-based, case-control study, Epidemiological Investigation of Multiple Sclerosis (EIMS), comprising the Swedish general population aged between 16-70 years. Incident cases were recruited from hospital-based and privately run neurology units. Cases were diagnosed by local neurologists based on the McDonald criteria. For each case, 2 control individuals were randomly chosen from the general population register, which were matched by age in 5-year age-groups, sex, and residential area.
The present study focused on sleeping patterns and shift work in individuals aged between 15-19 years. A total of 2075 cases and 3164 controls individuals were included in the current analysis. The mean age at MS onset was 34.8±10.8 years.
The researchers found an association between sleep duration and sleep quality among both cases (95% CI, 0.28-0.36) and control individuals (95% CI, 0.28-0.32), which remained similar when the analysis was stratified according to shift work.
Compared with a sleep duration of 7-9 hours per night, a short sleep duration (ie, <7 hours per night) was associated with an increased risk for the development of MS (odds ratio [OR], 1.4; 95% CI, 1.1-1.7), whereas long sleep duration (ie, ≥10 hours per night) was not associated with an elevated risk for MS. Subjective low sleep quality during childhood increased the risk of developing MS (OR, 1.5; 95% CI, 1.3-1.9); however, phase shift did not significantly affect this risk.
Additionally, the correlation between short sleep duration during work/schooldays and subsequent risk for MS remained significant when the analysis was restricted to participants who slept ≥7 hours during weekends or free days (OR, 1.3; 95% CI, 1.1-1.7).
Several possible limitations of the study should be noted. For example, since sleep restriction or altered sleep habits may be a consequence of neurodegeneration, the researchers focused mainly on evaluating the possible association between sleep habits during the 15- to 19-year-old age period and subsequent MS risk. Although supplementary analyses showed that short sleep and poor sleep quality may be important, possibly modifiable risk factors for MS, the findings should be interpreted with caution because of the potential for reverse causation. Further, since sleep disorders are common among individuals with MS and many patients with the disease experience fatigue, the possibility exists that cases may recall prior sleep habits differently from control individuals.
Overall, insufficient sleep and low sleep quality during childhood can significantly increase the risk of developing MS in adulthood.
“Sufficient restorative sleep at young age, needed for adequate immune functioning, may be a preventive factor against MS,” the researchers concluded.
Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Åkerstedt T, Olsson T, Alfredsson L, Hedström AK. Insufficient sleep during adolescence and risk of multiple sclerosis: results from a Swedish case-control study. J Neurol Neurosurg Psychiatry. Published online January 23, 2023. doi:10.1136/jnnp-2022-330123