TY  - JOUR
T1  - PHysical activity, vascular health, and cognitive impairment
AU  - Smith PJ
Y1  - 2012/01/09
N1  - 10.1001/archinternmed.2011.615
JO  - Archives of Internal Medicine
SP  - 83
EP  - 84
VL  - 172
IS  - 1
N2  - 
First, the study is observational and does not provide causal evidence that physical activity preserves cognitive function. Second, we3 and others4 have demonstrated that dietary patterns are an important lifestyle determinant of cognitive function and, although this cohort was taken from participants in the Women's Antioxidant Cardiovascular Study, no dietary factors were examined. Third, the study used a telephone-based measure of cognitive function, which has limited validity when compared with traditional in-person assessment techniques. Similarly, the study by Middleton and colleagues1 found that higher activity energy expenditure (AEE), quantified by doubly labeled water, was associated with a lower incidence of cognitive impairment, defined as a 1.0-SD decrease on the Modified Mini-Mental Status Examination (3MS). We are concerned, however, that cognitive impairment was identified only by change scores on the 3MS, a brief cognitive measure that may have underidentified individuals with cognitive impairment. Screening measures such as the 3MS often have limited sensitivity among individuals with higher premorbid intellectual functioning, so, although this measure provides interesting epidemiological information, it may also be diagnostically limited among some subgroups of patients. In addition, it is unclear why the authors found that AEE, but not physical activity level, was protective against incident cognitive impairment. Another possibility is that fitness levels may explain the AEE and cognitive impairment relationship, as we have previously shown that higher levels of objectively measured cardiorespiratory fitness may mediate improvements in cognitive function from aerobic exercise.3 This is particularly important because the intensity and duration of aerobic exercise interventions among randomized trials do not appear to differentially predict improvements in cognitive function,5 suggesting that other lifestyle factors, such as diet, may provide important additional information.

SN  - 0003-9926
M3  - doi: 10.1001/archinternmed.2011.615
UR  - http://dx.doi.org/10.1001/archinternmed.2011.615
ER  -