Celia Oreja-Guevara
Head of the Neurology Section and coordinator of the Multiple Sclerosis Unit at the Hospital Clínico San Carlos.
Multiple sclerosis is an autoimmune disease that mainly affects young women. The cause of multiple sclerosis is as yet unknown. However, there are a number of risk factors that influence the onset of the disease, such as Epstein Barr virus infection, obesity in young people, low vitamin D, poor diet, etc. In addition, shift work does play a role in the disease.
Other studies of neurological diseases such as cognitive impairment have found a link between sleep deprivation and poor sleep quality and the risk of neurodegenerative diseases.
This study looks at other factors that may influence the onset of this disease, such as too little sleep and poor quality sleep. The overall study is well done and is based on the Swedish registry, which has good quality data. As they say, the limitations are that they have not been able to rule out other factors such as stress and dietary habits.
It is a very interesting study and will need to be replicated in other populations, as this is a Swedish study only.
The study concludes that insufficient sleep of less than seven hours and of poor quality during adolescence increases the risk of developing multiple sclerosis. Another important point is that a shift in sleep hours between weekdays and weekends does not influence the disease.
The study provides an important new risk factor, because it is a preventable and avoidable factor. Adolescents could be educated to sleep at least seven hours and not to reduce their sleep hours by using social networks, among other things.
In general, I think it is an interesting study that needs to be replicated in other populations, very well done, based on a national registry and that, if confirmed, can help to avoid this factor and therefore reduce the risk of developing multiple sclerosis.