Interactive relations of central versus total obesity and blood pressure to cognitive function.

OBJECTIVE: To examine the potential interactive relations of central versus total obesity and blood pressure (BP) to cognitive function.
METHOD: In all, 90 healthy, stroke, and dementia-free middle-aged and older adults (ages 54-81 years; 63% male; 93% White) underwent biomedical and neuropsychological assessment. Relations of central obesity (assessed by waist circumference (WC)) and systolic or diastolic BP to cognitive function were examined in multiple regression models. Next, body mass index (BMI) was substituted for WC in the models.
RESULTS: After statistical adjustment for age, education, gender, and other potential confounders including components of the metabolic syndrome (depending on the model), significant interactions of WC and systolic (or diastolic) BP were noted for the Grooved Pegboard - Dominant Hand and Stroop Interference scores, with marginally significant results for Grooved Pegboard - Nondominant Hand. In general, individuals with greater WC and higher BP performed most poorly on these measures. Similar results were obtained for BMI.
CONCLUSION: Independent of other confounders including facets of the metabolic syndrome, the combination of greater WC (or BMI) and higher (systolic or diastolic) BP was associated with diminished performance on tests of motor speed and manual dexterity, and executive function (i.e. response inhibition) accounting for 3-13% of the variance in these measures. In healthy older adults, there are similar, negative relations of central and total obesity to cognitive function that are potentiated by higher BP levels.