MS Speaks

Exercising won't keep you from getting MS, according to this. Exercising when you have MS, to keep your muscles active, is definitely helpful, though. (Emphasis added in the article below.)

From MedPage Today, October 1, 2016:

Exercise Won't Keep MS at Bay for Women

Analysis of Nurses Health Study cohorts suggests no protective effect

by Kate Kneisel
Contributing Writer, MedPage Today


Physical activity during early life and adulthood does not appear to reduce a woman's risk of developing multiple sclerosis (MS), researchers found.

In two prospective cohorts of more than 193,000 women who participated in the Nurses' Health Study and the Nurses' Health Study II, those in the highest quartile of baseline physical activity had a 27% reduced rate of MS compared with those in the lowest quartile -- but this only trended toward significance (P=0.08), according to Kassandra Munger, ScD, of the Harvard T.H. Chan School of Public Health, and colleagues.

Additionally, the trend was not observed in a 6-year lagged analysis, they reported online in Neurology.

"Overall, there was no consistent association of exercise at any age and MS," Munger said in a statement. "Exercise has been shown to be beneficial to people with the disease, but it seems unlikely that exercise protects against the risk of developing MS."

Exercise has been shown to benefit patients with mild or moderate MS, and some work has suggested it may even slow the progression of the disease, but little research has focused on the association between physical activity and risk of developing MS, the researchers said.

So they assessed women in the the Nurses Health Study cohorts who were followed for up to 20 years and who had completed regular questionnaires about current and past physical activity as teens and young adults. During the course of those studies, a total of 341 women developed MS.

In addition to the lack of an association between baseline activity levels and subsequent MS risk, the researchers found no association beween reports of early-life physical activity and MS.

They also found no association between moderate activity and incident MS (RR 0.90, 95% CI 0.66–1.22, P-trend=0.34).

Further analyses suggested that physical activity levels fell among women with MS over time, compared with women without MS. There was also a decrease in activity up to 6 years before the first symptoms of MS appeared, the authors said.

Christina Wolfson, PhD, of McGill University in Montreal, who was not involved with the study, said this finding "supports the hypothesis of decreased activity due to subclinical MS."

"A finding of a reduced risk due to higher levels of physical activity reflects a reduction in physical activity prior to onset of the disease rather than a true risk factor," Wolfson told MedPage Today.

A novel aspect of this research, Wolfson said, is that measures of physical activity were taken before the onset of disease, potentially preventing recall bias, as "participants' recall of their behavior patterns could be influenced by having received a diagnosis of MS, with the potential to affect reliability of the findings."

"This group has conducted a very important study which will no doubt encourage other researchers to re-evaluate their own findings and perhaps re-assess their measurement strategies and analyses to allow them to take into account the challenge of the apparent decrease in physical activity in response to subclinical symptoms," Wolfson said.

Although physical activity appears not to play a major role in the etiology of MS, it is important because of its benefits on cardiovascular and other outcomes in people with MS, Munger told MedPage Today.

"In fact, there is a growing body of work, lead by Dr. Robert Motl, suggesting that physical activity in persons with MS may be beneficial, and should be recommended because of its [positive] effects on cardiovascular outcomes, which are a major cause of morbidity and mortality in individuals with MS," Munger said.

The study was limited by a lack of validation of early-life physical activity and of adult activity against accelerometry data or fitness, although they predicted that any measurement errors would be nondifferential given the study's prospective design. The possible misdiagnosis of some MS cases was also noted, as was the potential for bias due to confounding effect of behaviors beyond vitamin D intake and smoking on physical activity. Finally, the exclusively female and 95% Caucasian participants interfere with generalizability of the results.

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Some authors reported research support from the National Institutes of Health, the National Multiple Sclerosis Society, the Department of Defense, Merck-Serono and Novartis Pharmaceuticals; personal compensation for advisory board/consulting for Biogen-Idec, Genzyme-Sanofi, Roche, and Bayer HealthCare.

This work was supported by the U.S. National Institutes of Health.

Reviewed by F. Perry Wilson, MD, MSCE Assistant Professor, Section of Nephrology, Yale School of Medicine and Dorothy Caputo, MA, BSN, RN, Nurse Planner

http://www.medpagetoday.com/Neurology/MultipleSclerosis/60535?xid=nl_mpt_DHE_2016-10-01&eun=g345846d0r&pos=1