A new research study from the Danish Multiple Sclerosis Center, Department of Neurology at Rigshospitalet has revealed a link between later onset of sclerosis and exposure to daily sunlight as a teenager. The study has recently been published in the prestigious American journal, Neurology.
"Our survey shows that exposure to sunlight as a teenager may be connected to later onset of sclerosis. We are still trying to understand the causes of sclerosis, but numerous research studies have now shown that sunlight and vitamin D may have a protecting effect against the disease," said Julie Hejgaard Laursen, physician and PhD at the Danish Multiple Sclerosis Center, Rigshospitalet.
Daily sunlight can delay the onset of sclerosis
Danish researchers have interviewed 1161 sclerosis patients about their sunbathing habits as teenagers. The researchers divided the patients into two groups; those who spent time in the sun every day during the summer months, and those who did not.
The group of patients, who had spent time in the sun every day as teenagers, on average developed sclerosis 1.9 years later than the other group. Patients, who spent time in the sun every day, on average developed sclerosis at the age of 32.9, while those who were not exposed to the sun daily, developed the disease at an average age of 31 years.
Obesity can accelerate the onset of sclerosis
The research team at Rigshospitalet has also demonstrated a connection between teenage obesity and an accelerated onset of sclerosis. The patients, who were obese as 20 year-olds, on average developed sclerosis 1.6 years earlier than patients with an average weight, and 3.1 years earlier than patients who were underweight.
"Our research suggests that a high BMI when patients were teenagers can accelerate the development of sclerosis and thus could be a risk factor for the onset of the disease. However, we cannot conclude that being underweight delays the development of sclerosis. But the results show that BMI is one of the lifestyle factors that can affect the development of the disease," said Julie Hejgaard Laursen.
Sclerosis is a chronic disease which most often affects women and typically occurs at the age of 20 to 40. The cause of the sclerosis is unknown. When the disease does present itself, it is the result of an unfortunate coincidence of genetic factors affecting the immune system, combined with lifestyle and environmental factors, including viral infections.