Cognitive decline precedes late-life longitudinal changes in vascular risk factors.

INTRODUCTION: Although obesity, hypercholesterolaemia and hypertension in midlife are risk factors for dementia in late life, dementia is associated with lower body mass index, cholesterol levels and blood pressures. It is unclear whether declines in these vascular risk factors are preceded by declines in cognitive function or vice versa. METHODS: Within the Leiden 85-plus Study, a prospective population-based study of 599 subjects aged 85 years, the authors annually measured body mass index, total cholesterol, high-density lipoprotein (HDL) cholesterol, glucose levels and blood pressure, and assessed global cognitive function using the Mini Mental State Examination (MMSE) during a 5-year follow-up. RESULTS: For the whole population who survived up to the age of 90 years, strong annual declines in MMSE score, body mass index, total cholesterol levels, glucose levels, and blood pressure, and an annual increase in HDL cholesterol levels were observed during the follow-up period (all p< or =0.010). Annual changes in MMSE score from age 85 to 87 years were associated positively with annual changes from age 87 to 90 years in total and HDL cholesterol levels (p=0.002 and p=0.013), systolic and diastolic blood pressure (p=0.008 and p=0.048), but not BMI. Parameter value changes from age 85 to 87 years were not associated with changes in MMSE score from age 87 to 90 years. DISCUSSION: In old age, cognitive decline precedes declines in total cholesterol levels, HDL cholesterol levels and blood pressure, and not vice versa. Possibly, brain lesions in metabolic and blood pressure regulation centres cause dysregulation of lipid metabolism and blood pressure.