【研究顯示減少不佳情形】
Etgen醫師與其團隊在他們的研究中，檢視了於2001至2003年招募自「the Intervention Projecton Cerebrovascular Diseases and Dementia in the Community ofEbersberg, Bavaria study (INVADE)」研究的3,903名病患，每3個月追蹤一次、為期兩年。所有病患都完成一個有6項的認知不全檢測以及一份問卷，根據活動程度將他們分成以下組別：沒有運動組(n = 584人)、適度運動組(n = 1523人)以及高度運動組(n = 1796)。
Exercise May Improve Cognitive Skills in Older Population
By Deborah Brauser
Medscape Medical News
January 28, 2010 — Participating in a sustained exercise program may decrease cognitive decline in patients older than 55 years, according to results from 2 new studies published in the January 25 issue of the Archives of Internal Medicine.
In a cohort study from Germany, investigators found that moderate or high physical activity was associated with a lower risk of developing cognitive impairment in patients older than 55 years.
The second randomized controlled study showed that resistance training programs improved the cognitive skills of attention and conflict resolution in women between the ages of 65 and 75 years in Canada.
"Our population-based prospective study of a large cohort of elderly subjects found that lack of physical activity yielded a significant association with incident cognitive impairment after 2 years," write Thorleif Etgen, MD, assistant professor in the Department of Psychiatry and Psychotherapy at the Technische Universitat in Munich, Germany, and colleagues.
In an interview with Medscape Neurology, Dr. Etgen said that he was amazed at the extent of the findings. "Physical activity cut in half the odds of developing incident cognitive impairment. We were also surprised that moderate physical activity had nearly the same effect as high physical activity."
"The population of older adults is expanding, and with this, the incidence of cognitive decline and dementia is growing," he added. "There is a high demand for powerful and inexpensive methods of preventing or delaying these declines."
Study Shows Decreased Impairment
In their study, Dr. Etgen and his team examined a cohort of 3903 patients enrolled in the Intervention Projecton Cerebrovascular Diseases and Dementia in the Community ofEbersberg, Bavaria study (INVADE) between 2001 and 2003 and followed up every 3 months for 2 years. All patients had filled out 6-item Cognitive Impairment Tests and a questionnaire that divided them by activity levels: none (n = 584), moderate (n = 1523), and high (n = 1796).
Moderate activity was defined as strenuous activities (including walking, hiking, bicycling, and swimming) performed fewer than 3 days a week, whereas high activity was defined as 3 or more times a week of participation.
"We were hoping to establish some protective effect of physical activity," said Dr. Etgen. "As most studies in the past focused on dementia, our aim of this part of the INVADE study was to further explore the association between cognitive impairment (as an early form of dementia) and physical activity."
At baseline, 418 participants (10.7%) had cognitive impairment. Of these, 21.4% were in the no activity group compared with 10.5% and 7.3% in the moderate and high activity groups, respectively.
At the end of 2 years, the investigators found that 207 additional patients (5.9%) had developed impairment. Although the incidence of new cognitive impairment among those with no physical activity was 13.9%, the incidence was significantly lower at only 6.7% (odds ratio [OR], 0.57; 95% confidence interval [CI], 0.37 – 0.87; P = .01) and 5.1% (OR, 0.54; 95% CI, 0.35 – 0.83; P = .005) in those who underwent moderate and high activity, respectively.
This association remained statistically significant even after adjusting for age, sex, depression, chronic kidney disease, and cardiovascular risk factors.
"The take-home message is: keep on moving," said Dr. Etgen. "Clinicians should more actively ask their patients about their physical activity and alert their elder patients to perform some sort of regular physical activity."
Resistance Training Improves Cognitive Skills
In the second study, investigators sought to examine the association between resistance training and improved cognition in older women.
"To our knowledge, no study to date has examined the minimum frequency of resistance training required for cognitive benefits," write Teresa Liu-Ambrose, PhD, PT, researcher at the Center for Hip Health and Mobility at Vancouver General Hospital and assistant professor at the Department of Physical Therapy at the University of British Columbia in Canada, and colleagues.
"We were interested in resistance training specifically because it has multiple benefits over other training as it relates to falls and fracture prevention," added Dr. Liu-Ambrose to Medscape Neurology. "We know that it benefits bone health, prevents muscle loss, and helps strengthen mass. However, most studies looking at the benefits of exercise for cognition have focused on aerobic training."
Her team enrolled 155 women between the ages of 65 and 75 years and randomized them to undergo either once-weekly (n = 54) or twice-weekly (n = 52) resistance training classes or twice-weekly balance and tone training classes (control group, n = 49) between May 2007 and April 2008.
All patients took the Stroop executive test on selective attention and conflict resolution and Trail Making Tests. Gait speed and whole brain volume were also measured.
Results at the end of 1 year showed that the patients in both of the resistance training groups had significantly improved scores on the Stroop test compared with the control group patients (P ? .03). In addition, "task performance improved by 12.6% and 10.9% in the once-weekly and twice-weekly resistance training groups, respectively. It deteriorated by 0.5% in the balance and tone group," write the study authors.
However, surprisingly, both resistance training groups also showed significant reductions in whole-brain volume compared with the control group (P < .03).
"This reduction was a surprising finding because that's usually associated with poor cognitive function. We are currently looking at more data to specifically assess grey and white matter volume," said Dr. Liu-Ambrose.
Finally, enhanced selective attention and conflict resolution were significantly associated with increased gait speed (P < .01).
"This finding was quite clinically relevant because walking speed is a big indicator of a person's general well-being and also a predictor of mortality," explained Dr. Liu-Ambrose.
Overall, "the results have important clinical implications," write the study authors. However, because of the patient population studied, "the findings may not generalize to men or to women of other ages."
In addition, they note that the cognitive benefits were found after 12 months of training but not at the 6-month trial midpoint.
"This could be because there was a lot of motor learning and motor teaching in terms of resistance training for this group, especially for the first 2 to 3 months of this study," explained Dr. Liu-Ambrose. "So there was a lag time between teaching the technique and them becoming comfortable with it."
She said that her takeaway from this study is that resistance training should be more widely promoted. "I think that exercise is currently promoted clinically but I think it's typically more, 'Take more walks.' But there is a lot of emerging evidence that shows that resistance training not only has similar benefits as aerobic training, but it also has very specific benefits. It's also an option for seniors with limited mobility."
Dr. Ambrose reported that her team hopes to continue following this patient group and is in the middle of a new trial comparing aerobic training to resistance training and to tone and balance training in an at-risk patient population.
Promising Evidence
"Both studies provide very promising evidence that physical activity in any form can improve cognitive function," Marco Pahor, MD, professor and director at the Institute on Aging and chair of the Department of Aging and Geriatric Research at the University of Florida in Gainesville, told Medscape Neurology. Dr. Pahor wrote the accompanying editorial with his colleague Jeff Williamson, MD, MHS, chief of the Division of Geriatric Medicine at Wake Forest University Medical Center in Winston-Salem, North Carolina.
"However, both studies have some limitations," cautioned Dr. Pahor. "The primary limitation of the Etgen study is that it is observational and doesn't provide definitive evidence of cause and effect. The Canadian study is a randomized controlled trial but has a limited sample size of participants and a short duration of 12 months, which is a short time to access the effects on cognition."
"The takeaway is that they provide 1 more piece of evidence that physical activity is a very important factor for improving health in older adults," he concluded. "Both studies are extremely compelling and set the stage for larger multicenter trials to come."
The first study was funded by Allgemeine Orskrankenkasse (a Bavarian health insurance company). The second study was funded by grants from The Vancouver Foundation, the Natural Sciences and Engineering Research Council of Canada, and the Michael Smith Foundation for Health Research and by a New Opportunities Fund from the Canada Foundation for Innovation. None of the study or editorial authors have disclosed any relevant financial relationships.
