For young people, type 1 diabetes may raise the likelihood of having multiple sclerosis. Scientists now suspect that certain environmental factors may play a role.
Type 1 diabetes and multiple sclerosis (MS) are both autoimmune diseases, meaning a person's immune system causes damage to their own body.
Type 1 diabetes (sometimes called juvenile diabetes because it is usually diagnosed in childhood) is an autoimmune attack against the beta cells in the pancreas while, with multiple sclerosis, the immune system attacks the brain and spinal cord.
Recent research backed up previous studies which found that children and adolescents with diabetes face greater odds of getting MS. Investigators discovered that environmental factors, including when a person is born, may heighten this risk.
Susanne Bechtold, MD, in the Department of Pediatrics, Medical University Munich, Germany, and a team of researchers analyzed data on 56,653 children and adolescents with type 1 diabetes under the age of 21 from Germany and Austria.
The authors discovered 19 of these patients had MS.
Researchers compared MS prevalence rates from the Mid-European and German MS pediatric and adult registers with their data. They calculated an MS prevalence of 7 to 10 patients per 100,000 with type 1 diabetes, compared with 3 to 5 cases per 100,000 in a non-diabetes population.
The risk of the diabetes patients having MS was three to almost five times greater.
The investigators also cited three possible influencing factors that could be adding to the risk of developing MS—immigration status, thyroid antibodies (only in males) and month of birth.
There was a higher MS risk in patients with an immigrant background. The authors wrote "...we assume that variations in their genetic, environmental or cultural background caused this significantly increased risk to simultaneously develop type 1 diabetes and MS."
Male patients with thyroid specific antibodies also had a higher chance of developing MS. Thyroid antibodies are an immune response of the body, which is considered to be abnormal.
Also, researchers noted that among the diabetes-MS patients, dates of birth peaked in June and August.
Dr. Bechtold told dailyRx News, “We think that environmental factors might influence the immunological system, like by vitamin D level during early pregnancy. The theory regarding month of birth is that vitamin D has immune-modulating capacities.”
This study found that two-thirds of patients with type 1 diabetes and MS had a birth month consistent with the fetus having experienced lower levels of ultraviolet exposure during early pregnancy. Exposure to sunlight can be a source of vitamin D.
“Overall this is speculation and I am not aware on any study investigating the influence of different environmental factors in detail on the fetus,” said Dr. Bechtold.
The authors qualified their results, writing that the low number of MS patients did not reach statistical significance.
“In the next step, we are going to contact each of the 19 patients to get more detailed information of history, family history and immunological data,” Dr. Bechtold told dailyRx News. “Only with these hopefully more detailed knowledge we may give advice.”
The study was published online in September in Diabetes Care ahead of print.