Summary: Researchers find no evidence that exercise may reduce the risk of developing multiple sclerosis in women.
A large, new study shows no evidence that exercise may reduce a woman’s risk of developing multiple sclerosis (MS). The research is published in the September 28, 2016, online issue of Neurology. Previous small studies had shown conflicting results.
“We wanted to find out if exercise lowered the risk of developing MS in women,” said study author Kassandra Munger, ScD, of the Harvard T.H. Chan School of Public Health in Boston, Mass. “Our study did not provide evidence to support it.”
Researchers evaluated data on more than 193,000 women who participated in the Nurses’ Health Study and Nurses’ Health Study II and were followed for up to 20 years. The women completed regular questionnaires about their physical activity and also about their activity as teens and young adults. During the study, 341 women developed MS.
Researchers calculated the total hours of physical activity per week, took into account the type of exercise for each woman and adjusted for age, ethnicity, smoking, supplemental vitamin D, place of residence at age 15 and body mass index at age 18.
“Overall, there was no consistent association of exercise at any age and MS,” Munger said. “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.”
Funding: The study was supported by the National Institutes of Health.
Source:AAN Image Source: This NeuroscienceNews.com image is in the public domain. Original Research:Abstract for “Physical activity and the incidence of multiple sclerosis” by Kirsten S. Dorans, ScD, Jennifer Massa, ScD, Tanuja Chitnis, MD, Alberto Ascherio, MD, DrPH and Kassandra L. Munger, ScD in Military Medicine. Published online September 28 2016 doi:10.1212/WNL.0000000000003260
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[cbtabs][cbtab title=”MLA”]AAN. “Exercise Not Shown to Reduce Risk of Developing Multiple Sclerosis in Women.” NeuroscienceNews. NeuroscienceNews, 1 October 2016. <https://neurosciencenews.com/ms-women-exercise-neurology-5174/>.[/cbtab][cbtab title=”APA”]AAN. (2016, October 1). Exercise Not Shown to Reduce Risk of Developing Multiple Sclerosis in Women. NeuroscienceNews. Retrieved October 1, 2016 from https://neurosciencenews.com/ms-women-exercise-neurology-5174/[/cbtab][cbtab title=”Chicago”]AAN. “Exercise Not Shown to Reduce Risk of Developing Multiple Sclerosis in Women.” https://neurosciencenews.com/ms-women-exercise-neurology-5174/ (accessed October 1, 2016).[/cbtab][/cbtabs]
Physical activity and the incidence of multiple sclerosis
Objective: To study whether physical activity during adulthood or early life is associated with multiple sclerosis (MS) incidence in 2 prospective cohorts of women.
Methods: Women in the Nurses’ Health Study (NHS) (n = 81,723; 1986–2004) and NHS II (n = 111,804; 1989–2009) reported recent physical activity at baseline and in selected follow-up questionnaires. Using this information, we calculated total metabolic equivalent hours of physical activity per week, a measure of energy expenditure. There were 341 confirmed MS cases with first symptoms after baseline. Participants also reported early-life activity. To estimate relative rates (RRs) and 95% confidence intervals (CIs), we used Cox proportional hazards models, adjusting for age, latitude of residence at age 15, ethnicity, smoking, supplemental vitamin D, and body mass index at age 18.
Results: Compared with women in the lowest baseline physical activity quartile, women in the highest quartile had a 27% reduced rate of MS (RRpooled = 0.73, 95% CI 0.55–0.98; p-trend 0.08); this trend was not present in 6-year lagged analyses. Change in physical activity analyses suggested that women reduced activity before onset of MS symptoms. In NHS and NHS II, higher strenuous activity at ages 18–22 years was weakly associated with a decreased MS rate. However, in NHS II, total early-life activity at ages 12–22 was not associated with MS.
Conclusions: Though higher physical activity at baseline was weakly associated with lower MS risk, this may have been due to women reducing physical activity in response to subclinical MS.
“Physical activity and the incidence of multiple sclerosis” by Kirsten S. Dorans, ScD, Jennifer Massa, ScD, Tanuja Chitnis, MD, Alberto Ascherio, MD, DrPH and Kassandra L. Munger, ScD in Military Medicine. Published online September 28 2016 doi:10.1212/WNL.0000000000003260