中等度の運動が脳卒中リスク低下と最も関連する（Abstract: TMP67）

中等度の運動が女性の脳卒中リスクを低下させホルモン補充療法によるリスク上昇を相殺するのに役立つ

Moderate physical activity cuts women's stroke risk and helps offset increased risk from hormone therapy

女性が脳卒中リスクを低下させるためにマラソンをしたりハードなエアロビクスをする必要はない。早歩きやテニスなどの中等度の運動で十分であろうとの研究結果が2014年American Stroke Association's International Stroke Conferenceで発表された。研究者らはCalifornia Teachers Studyの対象女性133,479人の情報を解析し、何人が脳卒中を発症したかを観察した。スタディに登録する前の3年間に中等度の運動をしていたと回答した者は、運動をしなかったと回答した者よりも脳卒中に罹患する確率が20%低かった。この脳卒中リスク低下効果は、中等度の運動を少しずつ持続的に行っている女性群においても認められた。スタディの結果、中等度の運動はホルモン補充療法を受けている閉経後女性に認められる脳卒中リスク上昇を相殺するのに役立つことも明らかにされたが、完全に相殺したわけではなった。ホルモン補充療法を受けている閉経後女性は、一度もホルモン療法を受けたことがない女性よりも脳卒中リスクが30%以上高かった。ホルモン内服を中止するとリスクは低下し始めた。さらに、糖尿病の女性は脳卒中リスクが高かったが、この中には過剰体重の女性も含まれていた。

Women don't need to run marathons or do intense aerobics to reduce their stroke risk. Moderate-intensity exercise — such as brisk walking or playing tennis — may be enough, according to research presented at the American Stroke Association's International Stroke Conference 2014.

"I was surprised that moderate physical activity was most strongly associated with a reduced risk of stroke," said Sophia Wang, Ph.D., the study's lead author and professor in the department of population sciences within the Beckman Research Institute at the City of Hope in Duarte, Calif. "More strenuous activity such as running didn't further reduce women's stroke risk. Moderate activity, such as brisk walking appeared to be ideal in this scenario."

The study found that moderate exercise also helps offset the increased stroke risk seen with postmenopausal women taking menopausal hormones, but not completely.

Researchers analyzed information from the 133,479 women in the California Teachers Study to see how many suffered a stroke between 1996 and 2010. Those who reported doing moderate physical activity in the three years before enrolling in the study were 20 percent less likely than women who reported no activity to suffer a stroke. "The benefits of reducing risk of stroke were further observed among the group of women who had a sustained moderate level of physical activity over time," she said.

Postmenopausal women taking menopausal hormone therapy had more than a 30 percent higher risk of stroke than women who never used menopausal hormone therapy. After the women stopped taking hormones, their risk began to diminish.

"The effects of physical activity and hormone therapy appear immediate and the benefits of physical activity are consistent in premenopausal and postmenopausal women," Wang said. Therefore, Wang recommends that women incorporate some type of physical activity into their daily routine. "You don't have to do an extreme boot camp. The types of activities we're talking about are accessible to most of the population." Power walking and recreational tennis, for example, do not necessarily require special memberships to gyms.

The study also found that women with diabetes had elevated stroke risk, although this group encompassed women who also were overweight. "Physical activity, obesity and diabetes are all highly correlated with one another," Wang said. "Stroke prevention among diabetics is thus a particularly important scientific question to address."

Although 87 percent of the women were white, Wang said she believes the study's results may also apply to women in other racial/ethnic groups because the amount of stroke risk reduction was so robust. Further studies are needed to determine how much moderate exercise helps those with diabetes avoid strokes.

Co-authors are: Leslie Bernstein, M.S., Ph.D.; James Lacey, Jr., M.P.H., Ph.D.; Kamakshi Lakshminarayan, M.D., Ph.D. Mitchell Elkind, M.D., M.S., M.Phil; Daniel Woo, M.D.; Ph.D.; Jenna Voutsinas, M.P.H.; and Chengyi Zhong, M.P.H.

The study was funded by the National Institute of Neurological Disorders and Stroke. The California Teachers Study group is funded by the National Cancer Institute.