Whitmer et al reported that obesity is a risk factor for dementia.
They proposed that adipocytokines may play a role in this relationship.1
There is an additional mechanism that should be considered.
Physical activity has been negatively associated with percent body
fat.2
Lytle et al found that among individuals aged 65 and over, exercise
was protective against cognitive decline.3 In a mouse model of Alzheimer
disease, treadmill exercise reduced A beta-42 deposits and improved
behavioral function.4
Exercise might exert its neuroprotective effects through alterations
in gene expression.5 Growth factors up-regulated by physical activity
promote neurogenesis, increase resistance to injury, and stimulate brain
plasticity.
Thus thinner individuals might be less prone to dementia in part
because they are more likely to have higher levels of physical activity.
1. Whitmer RA, Gunderson EP, Barrett-Connor E, Quesenberry CP Jr,
Yaffe K. Obesity in middle age and future risk of dementia: a 27 year
longitudinal population based study. BMJ. 2005; Apr 29
2. Gilliat-Wimberly M, Manore MM, Woolf K, Swan PD, Carroll SS. Effects of
habitual physical activity on the resting metabolic rates and body
compositions of women aged 35 to 50 years. J Am Diet Assoc.
2001;101(10):1181-8.
3. Lytle ME, Vander Bilt J, Pandav RS, Dodge HH, Ganguli M. Exercise level
and cognitive decline: the MoVIES project. Alzheimer Dis Assoc Disord.
2004;18(2):57-64.
4. Cho JY, Hwang DY, Kang TS, Shin DH, Hwang JH, Lim CH, Lee SH, Lim HJ,
Min SH, Seo SJ, Song YS, Nam KT, Lee KS, Cho JS, Kim YK. Use of NSE/PS2m-
transgenic mice in the study of the protective effect of exercise on
Alzheimer's disease. J Sports Sci. 2003;21(11):943-51.
5. Cotman CW, Berchtold NC. Exercise: a behavioral intervention to enhance
brain health and plasticity. Trends Neurosci. 2002;25(6):295-301.
Rapid Response:
Running from dementia
Whitmer et al reported that obesity is a risk factor for dementia. They proposed that adipocytokines may play a role in this relationship.1 There is an additional mechanism that should be considered.
Physical activity has been negatively associated with percent body fat.2
Lytle et al found that among individuals aged 65 and over, exercise was protective against cognitive decline.3 In a mouse model of Alzheimer disease, treadmill exercise reduced A beta-42 deposits and improved behavioral function.4
Exercise might exert its neuroprotective effects through alterations in gene expression.5 Growth factors up-regulated by physical activity promote neurogenesis, increase resistance to injury, and stimulate brain plasticity.
Thus thinner individuals might be less prone to dementia in part because they are more likely to have higher levels of physical activity.
1. Whitmer RA, Gunderson EP, Barrett-Connor E, Quesenberry CP Jr, Yaffe K. Obesity in middle age and future risk of dementia: a 27 year longitudinal population based study. BMJ. 2005; Apr 29
2. Gilliat-Wimberly M, Manore MM, Woolf K, Swan PD, Carroll SS. Effects of habitual physical activity on the resting metabolic rates and body compositions of women aged 35 to 50 years. J Am Diet Assoc. 2001;101(10):1181-8.
3. Lytle ME, Vander Bilt J, Pandav RS, Dodge HH, Ganguli M. Exercise level and cognitive decline: the MoVIES project. Alzheimer Dis Assoc Disord. 2004;18(2):57-64.
4. Cho JY, Hwang DY, Kang TS, Shin DH, Hwang JH, Lim CH, Lee SH, Lim HJ, Min SH, Seo SJ, Song YS, Nam KT, Lee KS, Cho JS, Kim YK. Use of NSE/PS2m- transgenic mice in the study of the protective effect of exercise on Alzheimer's disease. J Sports Sci. 2003;21(11):943-51.
5. Cotman CW, Berchtold NC. Exercise: a behavioral intervention to enhance brain health and plasticity. Trends Neurosci. 2002;25(6):295-301.
Competing interests: None declared
Competing interests: No competing interests