路透社今天(17日)報導，台灣的研究人員發現，患 有帶狀皰疹的人比較可能罹患多發性硬化症(multiple sclerosis)，帶狀皰疹的病人在第二年被診斷出多發性硬化症的機率，是其他人的4倍。這項研究並發表在傳染病學期刊(Journal of Infectious Diseases)上。
But the team led by Jiunn-Horng Kang at Taipei Medical University Hospital warned that their study did not show that shingles itself could cause MS, although there were "several potential mechanisms" that could explain why the two diseases are linked.
"Our findings support the notion that occurrence of MS could be associated with herpes zoster attack," Kang and colleagues wrote in the Journal of Infectious Diseases.
"We found a significantly higher risk for MS within one year of [a] herpes zoster attack compared with the control population."
Shingles is a painful condition caused by reactivation of the virus that causes chicken pox, known as varicella-zoster virus. Once a person has had chicken pox, the virus goes into a dormant state, dwelling in the body's nerve fibres.
However, in some people the virus can reactivate and cause shingles, which usually begins with a burning pain or itch in one location on one side of the body, followed by a rash of fluid-filled blisters.
MS occurs when the protective coating around nerve fibres begins to break down, slowing the brain's communication to the rest of the body. Symptoms include fatigue and problems with balance and muscle co-ordination, as well as memory loss and trouble with logical thinking in some people.
About 2.5 million people have MS worldwide, according to the Multiple Sclerosis Association of America. Most experience their first symptoms between the ages of 15 and 50.
Reviewing a database from the insurer that covers 98% of Taiwan's population, the researchers found more than 300 000 people with shingles. They compared them to nearly 950 000 others with similar characteristics, who didn't have the disease.
Over the course of a year, fewer than one in 10 000 in the group with shingles developed MS - but that was still nearly four times as many as in the group without shingles.
"After adjusting for monthly income and geographic region, the hazard of MS was 3.96 times greater for the study group than controls," the researchers wrote.
Kang said that shingles is associated with disruptions to the immune system, which in turn might trigger MS. Also, a reactivation of the shingles virus may "provoke a series of immune responses in the host which may be linked to MS", Kang said.
The authors cautioned that most people included in the study were Han Chinese, among whom MS occurs relatively infrequently, so the findings might not apply to Western populations.
In addition, the authors did not have information about whether people smoked or drank alcohol, another potential influence on the findings.
"These factors may be confounding to our results and need to be further explored," Kang added.