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Smoking is Found to Increase Relapses in RRMS Patients Receiving Interferon-Beta

March 29, 2018

A study suggests that cigarette smoking increases the relapse rate in patients that have relapsing-remitting multiple sclerosis (RRMS), that are being treated with interferon-beta. The findings also suggest that RRMS patients who currently smoke quit, they may have fewer relapses.

A number of studies have observed the link between environmental and lifestyle factors (such as how much sunlight and vitamin D patients get, and if they have an Epstein-Barr virus infection) and the risk of developing MS. While cigarette smoking is a well-known risk factor in MS, most studies have focused solely on the link between smoking and MS or the link between smoking and progression of the disease.

“Studies that addressed the relationship between smoking and disease activity in RRMS are rarer,” wrote the researchers. As a result of this observation, the team decided to investigate the matter and find out whether smoking during interferon-beta treatment would affect relapse rates.

Since previous research showed a link between smoking and gene mutations (HLA and NAT1) that made people more susceptible to developing MS, they looked at DNA from 834 RRMS patients in the Danish Multiple Sclerosis Biobank who were treated with interferon-beta. Researchers also looked at medical records of these patients two years prior to their start of interferon-beta.

The team also adjusted for patients’ sex, age at the start of treatment, and number of relapses in the two years before treatment began before they made any conclusions on possible links between smoking and their relapse rates. In the end, their key conclusion was that smoking increased by more than a quarter the number of relapses in patients on interferon-beta therapy.

“Each pack of cigarettes more per day during IFN-β treatment increased the number of relapses by 27%,” the team wrote. The researchers also found no association among smoking, relapses, and mutations of the HLA or NAT1 genes. “Our results confirm that lifestyle factors are important in MS, suggesting that smoking cessation may be associated with a reduction in disease activity.”

They also suggest that physicians should inform patients with MS about the harmful effect of smoking and increase focus on smoking cessation, even though it has not been formally proved that smoking cessation will decrease the disease activity in RRMS.