Post by KenNiemann on Jan 25, 2006 1:11:43 GMT -5
Regular Exercise May Delay Onset of Dementia CME
News Author: Laurie Barclay, MD
CME Author: Désirée Lie, MD, MSEd
Jan. 17, 2006 — Regular exercise may delay the onset of dementia, according to the results of a prospective cohort study reported in the January 17 issue of the Annals of Internal Medicine. The editorialists suggest that this is the limit of what can be learned from an observational study. While awaiting a randomized trial, they suggest that that these findings may provide the impetus to be physically active.
"We learned that a modest amount of exercise would reduce a person's risk of dementia by about 40%," lead author Eric B. Larson, MD, from the Center for Health Studies at Group Health Cooperative in Seattle, Wash, said in a news release. "That's a significant reduction."
For 6 years, the investigators followed 1,750 adults aged 65 years or older without cognitive impairment at baseline. At 2-year intervals, participants reported their patterns of exercise, including walking, hiking, aerobics, calisthenics, swimming, water aerobics, weight training, and stretching.
Of 1,740 participants with available data, 158 developed dementia during a mean follow-up of 6.2 ± 2.0 years, including 107 participants who were diagnosed as having Alzheimer Disease (AD). The rate of dementia was 13.0 per 1,000 person years for participants who exercised at least 3 times per week vs 19.7 per 1,000 person years for participants who exercised fewer than 3 times per week, yielding an age- and sex-adjusted hazard ratio of dementia of 0.62 (95% confidence interval [CI], 0.44 - 0.86; P = .004).
Risk reduction associated with exercise was greater in those with lower performance levels, and findings were similar for the subgroup of patients with incident AD.
The authors describe this study as the most definitive to date to characterize the relationship between exercise and risk for dementia. Earlier studies on this relationship have yielded conflicting results.
"The group that benefited the most were the people who were frailest at the start of the study," Dr. Larson says. "So this means that older people really should 'use it even after you start to lose it,' because exercise may slow the progression of age-related problems in thinking."
Study limitations were self-reported exercise frequency, poor measures of exercise "dose," possible residual confounding, and a study population including a relatively high proportion of regular exercisers at baseline.
The National Institute for Aging supported this study. One of the authors has disclosed that he or she received a grant from the National Institutes of Health.
In an accompanying editorial, Laura Podewils, MS, PhD, from the Centers for Disease Control and Prevention, and Eliseo Guallar, MD, DrPH, from the Johns Hopkins Bloomberg School of Public Health in Baltimore, Md, note that this study is the first to demonstrate an interaction between level of physical function and exercise and dementia risk.
The editorialists recommend future research to evaluate the causal relationship, if any, between physical activity and dementia risk association. An alternative explanation may be that physical activity is a proxy for 'life engagement,' cognitive activities or other lifestyle or sociodemographic characteristics. Future studies should also evaluate the type, frequency, intensity and duration of physical activity that are most beneficial in reducing dementia risk or delaying its onset.
"Current recommendations call for all adults, including the elderly, to perform 60 minutes of moderate-intensity physical activity daily to promote health and vigor and to decrease the risk for chronic illnesses and early death," Drs. Podewils and Guallar write. "These recommendations may also help maximize cognitive health and attenuate neurodegenerative disease processes in older age. Because more than 40% of adults older than 50 years of age express heightened fear about Alzheimer disease, perhaps that perspective will serve as an additional impetus to be physically active in later life."
Drs. Podewils and Guallar have disclosed no relevant financial relationships.
Ann Intern Med. 2006;144:73-81, 135-136
Learning Objectives for This Educational Activity
Upon completion of this activity, participants will be able to:
Describe the effect of regular exercise on incidence of dementia and AD.
Describe the association between physical performance and the protective effect of exercise on cognitive function.
Clinical Context
According to the authors, exercise may protect against dementia and declining brain function by improving cerebral blood flow and oxygen delivery and inducing fibroblast growth factor in the hippocampus. However, studies on the effect of exercise on cognitive function or dementia have yielded conflicting results, with one study demonstrating a protective effect and another showing no effect.
The current trial is a population-based, longitudinal, prospective cohort study comparing the incidence of dementia and AD in elderly persons who exercised regularly with those who did not exercise regularly at baseline for a 6-year period.
Study Highlights
Participants were 1,740 volunteers from the Seattle area Group Health Cooperative who were older than 65 years and in the Adult Changes in Thought study.
Inclusion criterion was Cognitive Ability Screening Instrument (CASI) score of 86 or above (the range of scores is 0 - 100 and a score of 86 corresponds to a Mini-Mental State Examination score of 25 - 26).
Exclusion criteria were existing dementia, residents of a nursing home, and participating in other studies.
Participants received biennial examinations and were rescreened with the CASI.
Those with CASI scores of less than 86 at follow-up received a full standardized examination. Diagnoses were then reviewed by a panel of 2 physicians and a neuropsychologist.
Dementia was diagnosed using the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, (DSM-IV) criteria, and type was determined using the National Institute of Neurological and Communicative Diseases and Stroke–Alzheimer's Disease and Related Disorders Association criteria for AD and DSM-IV for other types of dementia.
Physical exercise was assessed at baseline by asking participants the number of days per week they did each of the following activities for at least 15 minutes: walking, hiking, bicycling, aerobics or calisthenics, stretching, or other exercise.
Those exercising 3 or more times weekly (regular exercisers) were compared with those exercising less.
Physical function was assessed using the performance-based physical function (PPF) test with 4 tests: 10-ft timed walk, time to stand from seated 5 times balance test, and grip strength (score range, 0 - 16, with 16 being the best physical function).
Cognitive function was assessed using the CASI and depression using the Center for Epidemiologic Studies Depression scale (range, 0 - 33, with higher score representing more depression).
Cardiovascular and other disease, smoking, alcohol consumption, and dietary supplement use were variables.
Cox proportional hazards regression models were used in analysis.
Mean age was 73 to 78 years at baseline, 59% were women, 95% were white, 50% used multivitamins, 48% were nonsmokers, 45% were former smokers, and 42% were nondrinkers.
One third had comorbid hypertension, and 9% had diabetes. Self-rated health status was "good" to "very good" in 75%.
Mean follow-up was 6.2 years.
Of 1,740 participants, 1,185 remained dementia-free. 158 developed dementia of whom 107 had AD, 33 had vascular dementia, and 18 had other dementia.
Odds ratios of regular exercise were 0.62, 0.49, and 0.10 for participants who rated their health as "good," "fair," and "poor," respectively, vs those who rated their health as "excellent."
The incidence of dementia was 13.0 per 1,000 person-years for those who exercised 3 or more times weekly vs 19.7 per 1,000 person years for those who exercised less frequently.
The age- and sex-adjusted hazard ratio of dementia for the regular exercisers was 0.62 (P = .004).
Alcohol consumption, smoking, education, and supplement use were not associated with dementia.
The risk reduction in dementia was greater for those with lower PPF scores.
The hazard ratio for dementia by exercise were 0.58, 0.66, and 0.75 for persons with PPF scores of 10, 11, and 12, respectively.
Among those who exercised less than 3 times weekly, a 1-point increment in PPF score was associated with a hazard ratio of dementia of 0.89. Among those who exercise 3 or more times weekly, the corresponding hazard ratio was 1.01.
The hazard ratio of AD by exercise was 0.69, and a similar association with PPF scores was seen for AD as for dementia.
Pearls for Practice
Regular exercise 3 or more times weekly is associated with lower risk for dementia and AD in persons older than 65 years.
The protective effect of exercise on dementia and AD is greater in those with lower vs higher physical functioning.
News Author: Laurie Barclay, MD
CME Author: Désirée Lie, MD, MSEd
Jan. 17, 2006 — Regular exercise may delay the onset of dementia, according to the results of a prospective cohort study reported in the January 17 issue of the Annals of Internal Medicine. The editorialists suggest that this is the limit of what can be learned from an observational study. While awaiting a randomized trial, they suggest that that these findings may provide the impetus to be physically active.
"We learned that a modest amount of exercise would reduce a person's risk of dementia by about 40%," lead author Eric B. Larson, MD, from the Center for Health Studies at Group Health Cooperative in Seattle, Wash, said in a news release. "That's a significant reduction."
For 6 years, the investigators followed 1,750 adults aged 65 years or older without cognitive impairment at baseline. At 2-year intervals, participants reported their patterns of exercise, including walking, hiking, aerobics, calisthenics, swimming, water aerobics, weight training, and stretching.
Of 1,740 participants with available data, 158 developed dementia during a mean follow-up of 6.2 ± 2.0 years, including 107 participants who were diagnosed as having Alzheimer Disease (AD). The rate of dementia was 13.0 per 1,000 person years for participants who exercised at least 3 times per week vs 19.7 per 1,000 person years for participants who exercised fewer than 3 times per week, yielding an age- and sex-adjusted hazard ratio of dementia of 0.62 (95% confidence interval [CI], 0.44 - 0.86; P = .004).
Risk reduction associated with exercise was greater in those with lower performance levels, and findings were similar for the subgroup of patients with incident AD.
The authors describe this study as the most definitive to date to characterize the relationship between exercise and risk for dementia. Earlier studies on this relationship have yielded conflicting results.
"The group that benefited the most were the people who were frailest at the start of the study," Dr. Larson says. "So this means that older people really should 'use it even after you start to lose it,' because exercise may slow the progression of age-related problems in thinking."
Study limitations were self-reported exercise frequency, poor measures of exercise "dose," possible residual confounding, and a study population including a relatively high proportion of regular exercisers at baseline.
The National Institute for Aging supported this study. One of the authors has disclosed that he or she received a grant from the National Institutes of Health.
In an accompanying editorial, Laura Podewils, MS, PhD, from the Centers for Disease Control and Prevention, and Eliseo Guallar, MD, DrPH, from the Johns Hopkins Bloomberg School of Public Health in Baltimore, Md, note that this study is the first to demonstrate an interaction between level of physical function and exercise and dementia risk.
The editorialists recommend future research to evaluate the causal relationship, if any, between physical activity and dementia risk association. An alternative explanation may be that physical activity is a proxy for 'life engagement,' cognitive activities or other lifestyle or sociodemographic characteristics. Future studies should also evaluate the type, frequency, intensity and duration of physical activity that are most beneficial in reducing dementia risk or delaying its onset.
"Current recommendations call for all adults, including the elderly, to perform 60 minutes of moderate-intensity physical activity daily to promote health and vigor and to decrease the risk for chronic illnesses and early death," Drs. Podewils and Guallar write. "These recommendations may also help maximize cognitive health and attenuate neurodegenerative disease processes in older age. Because more than 40% of adults older than 50 years of age express heightened fear about Alzheimer disease, perhaps that perspective will serve as an additional impetus to be physically active in later life."
Drs. Podewils and Guallar have disclosed no relevant financial relationships.
Ann Intern Med. 2006;144:73-81, 135-136
Learning Objectives for This Educational Activity
Upon completion of this activity, participants will be able to:
Describe the effect of regular exercise on incidence of dementia and AD.
Describe the association between physical performance and the protective effect of exercise on cognitive function.
Clinical Context
According to the authors, exercise may protect against dementia and declining brain function by improving cerebral blood flow and oxygen delivery and inducing fibroblast growth factor in the hippocampus. However, studies on the effect of exercise on cognitive function or dementia have yielded conflicting results, with one study demonstrating a protective effect and another showing no effect.
The current trial is a population-based, longitudinal, prospective cohort study comparing the incidence of dementia and AD in elderly persons who exercised regularly with those who did not exercise regularly at baseline for a 6-year period.
Study Highlights
Participants were 1,740 volunteers from the Seattle area Group Health Cooperative who were older than 65 years and in the Adult Changes in Thought study.
Inclusion criterion was Cognitive Ability Screening Instrument (CASI) score of 86 or above (the range of scores is 0 - 100 and a score of 86 corresponds to a Mini-Mental State Examination score of 25 - 26).
Exclusion criteria were existing dementia, residents of a nursing home, and participating in other studies.
Participants received biennial examinations and were rescreened with the CASI.
Those with CASI scores of less than 86 at follow-up received a full standardized examination. Diagnoses were then reviewed by a panel of 2 physicians and a neuropsychologist.
Dementia was diagnosed using the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, (DSM-IV) criteria, and type was determined using the National Institute of Neurological and Communicative Diseases and Stroke–Alzheimer's Disease and Related Disorders Association criteria for AD and DSM-IV for other types of dementia.
Physical exercise was assessed at baseline by asking participants the number of days per week they did each of the following activities for at least 15 minutes: walking, hiking, bicycling, aerobics or calisthenics, stretching, or other exercise.
Those exercising 3 or more times weekly (regular exercisers) were compared with those exercising less.
Physical function was assessed using the performance-based physical function (PPF) test with 4 tests: 10-ft timed walk, time to stand from seated 5 times balance test, and grip strength (score range, 0 - 16, with 16 being the best physical function).
Cognitive function was assessed using the CASI and depression using the Center for Epidemiologic Studies Depression scale (range, 0 - 33, with higher score representing more depression).
Cardiovascular and other disease, smoking, alcohol consumption, and dietary supplement use were variables.
Cox proportional hazards regression models were used in analysis.
Mean age was 73 to 78 years at baseline, 59% were women, 95% were white, 50% used multivitamins, 48% were nonsmokers, 45% were former smokers, and 42% were nondrinkers.
One third had comorbid hypertension, and 9% had diabetes. Self-rated health status was "good" to "very good" in 75%.
Mean follow-up was 6.2 years.
Of 1,740 participants, 1,185 remained dementia-free. 158 developed dementia of whom 107 had AD, 33 had vascular dementia, and 18 had other dementia.
Odds ratios of regular exercise were 0.62, 0.49, and 0.10 for participants who rated their health as "good," "fair," and "poor," respectively, vs those who rated their health as "excellent."
The incidence of dementia was 13.0 per 1,000 person-years for those who exercised 3 or more times weekly vs 19.7 per 1,000 person years for those who exercised less frequently.
The age- and sex-adjusted hazard ratio of dementia for the regular exercisers was 0.62 (P = .004).
Alcohol consumption, smoking, education, and supplement use were not associated with dementia.
The risk reduction in dementia was greater for those with lower PPF scores.
The hazard ratio for dementia by exercise were 0.58, 0.66, and 0.75 for persons with PPF scores of 10, 11, and 12, respectively.
Among those who exercised less than 3 times weekly, a 1-point increment in PPF score was associated with a hazard ratio of dementia of 0.89. Among those who exercise 3 or more times weekly, the corresponding hazard ratio was 1.01.
The hazard ratio of AD by exercise was 0.69, and a similar association with PPF scores was seen for AD as for dementia.
Pearls for Practice
Regular exercise 3 or more times weekly is associated with lower risk for dementia and AD in persons older than 65 years.
The protective effect of exercise on dementia and AD is greater in those with lower vs higher physical functioning.