Patterns of adiposity, vascular phenotypes and cognitive function in the 1946 British Birth Cohort

Objectives: The relationship between long term exposure to whole body or central obesity and cognitive function as well as its potential determinants remain controversial. We assessed the association of different patterns of whole body and central adiposity exposure with cognitive function at 60-64 years, and the influence of vascular phenotypes on this association. Research Design and Methods: Data from 1249 participants of the prospective cohort MRC National Survey of Health and Development with adiposity (BMI and waist circumference, WC), vascular (carotid intima-media thickness and carotid-femoral pulse wave velocity) and cognitive function (memory, processing speed, reaction time) data at 60–64 were used to assess the associations between different patterns of adult WC or BMI exposure (from 36 years of age) and late midlife cognitive performance, as well as the proportion of this association explained by cardiovascular phenotypes. Results: Longer exposure to elevated WC was related with lower memory (p<0.001 for both) and longer choice reaction time (p=0.003). A faster gain of WC between 36-43 years were associated with the largest change in reaction time and memory test (P<0.05 for all). Similar associations with cognitive tests were observed when patterns of WC were substituted with patterns of BMI, but when WC and BMI were included in the same model, only patterns of WC remained significantly associated with cognitive function. Adjustment for vascular phenotypes, levels of cardiovascular risk factors, physical activity, education, childhood cognition and socio-economic position did not affect these associations. DISCUSSION: Longer exposure to elevated WC or BMI and faster WC or BMI gains between 36-43 years are related to lower cognitive functions at 60-64 years. Patterns of WC in adulthood could provide additional information in predicting late midlife cognitive functions than patterns of BMI. The acquisition of an adverse cardiovascular phenotype associated with adiposity is unlikely to account for these relationships.