Insufficient and Poor Sleep in Teen Years Increases Risk of MS: Study
Adolescents with poor sleep up to 50% more likely to develop MS
Teenagers with poor sleep quality or insufficient sleep — those who sleep less than seven hours a night — are 40% to 50% more likely to develop multiple sclerosis (MS) later in life than those who get adequate rest, according to a Swedish population-based study.
Differences in sleep timing between schooldays (or work) and weekends (or free days) did not affect MS risk.
“Insufficient sleep and low sleep quality during adolescence seem to increase the risk of subsequently developing MS,” the researchers wrote. “Sufficient restorative sleep, needed for adequate immune functioning, may thus be another preventive factor against MS.”
The study, “Insufficient sleep during adolescence and risk of multiple sclerosis: results from a Swedish case-control study,” was published in the Journal of Neurology, Neurosurgery and Psychiatry.
Insufficient sleep cited as less than seven hours per night
Shift work, particularly at a young age, has been linked to an elevated risk of multiple sclerosis. Poor sleep quality can stimulate pro-inflammatory immune pathways and is thought to increase the risk of chronic inflammatory diseases, such as MS.
However, whether disrupted sleep patterns — namely, poor sleep duration and sleep quality — increase MS risk has not been thoroughly examined.
To investigate further, researchers in Sweden conducted a population-based study using data from the Epidemiological Investigation of Multiple Sclerosis (EIMS). This longitudinal study, launched in 2004, involves people from the general Swedish population, ages 16–70.
Because shift work during adolescence has been associated with MS risk, and the disease may alter sleep, the team focused on sleeping patterns and shift work during the age period of 15–19 years.
In total, 2,075 MS patients, with a mean age of 34.8 at diagnosis, were selected from the registry. For each MS case, two unaffected people were randomly selected and matched by age, sex, and residential area to serve as controls. Data were collected using a standardized EIMS questionnaire, which included questions about sleep.
Overall, the analysis showed that people with short sleep — those who slept less than seven hours a night during adolescence — were 40% more likely to develop MS later in life, compared with those with a standard sleep duration of 7–9 hours per night. Having a longer sleep of 10 or more hours each night did not impact that likelihood, however.
When the analysis focused only on those who slept seven hours or more on weekends (or days off), short sleep duration during schooldays (or workdays) was still linked to a 30% higher MS likelihood.
The association between MS and poor sleep remained after adjusting for smoking status, body fat content, and a history of an Epstein-Barr viral infection at age 20. Co-existing conditions at age 20 and at MS onset also did not influence these findings, nor did the total weekly mean sleep duration.
Poor sleep quality also a risk factor
After establishing a link between MS and insufficient sleep, the team examined whether poor sleep quality also impacted MS development.
Indeed, participants with low sleep quality — indicating very bad to neither good nor bad sleep — during adolescence were 50% more likely to develop the neurodegenerative disorder than those reporting rather good to very good sleep.
Importantly, according to researchers, the association remained significant when the analysis was stratified by those who slept more or less than seven hours.
Further analyses taking into account both sleep duration and quality demonstrated that patients with increased sleep duration and sleep quality were significantly less likely to develop MS.
Educational interventions addressed to adolescents and their parents regarding the negative health consequences of insufficient sleep are of importance.
To determine whether only sleep patters during adolescence impacted MS risk, the researchers then examined the associations between MS development and sleep duration and quality at the time of MS diagnosis.
Short sleep at diagnosis was associated with increased MS risk regardless of sleep duration in adolescence, results showed. However, elevated risk was most pronounced among those who reported short sleep during adolescence and at diagnosis, with a 60% relative increase in the likelihood of having MS, compared with individuals with seven or more hours of sleep in both periods.
Also, poor sleep quality both during adolescence and at diagnosis was associated with a higher likelihood of MS, but the effect was even more pronounced among people who reported poor sleep quality during the two periods.
The researchers noted that “these findings should be interpreted with caution due to the potential of reverse causation,” meaning poor sleep may be a consequence, and not a cause, of neurological damage caused by undetected disease.
Previous studies have found that symptoms such as sleep disorders can begin as many as five years prior to the onset of the more well-known symptoms of MS.
“Insufficient or disturbed sleep is common among adolescents, which partially can be explained by physiological, psychological and social changes that occur during this age period,” the researchers wrote. “Associations have also been demonstrated between social media use and sleep patterns,” which “represents an important public health issue.”
“Educational interventions addressed to adolescents and their parents regarding the negative health consequences of insufficient sleep are of importance,” they added.