Metabolic cardiovascular syndrome and risk of dementia in Japanese-American elderly men - The Honolulu-Asia Aging Study

Cardiovascular risk factors often cluster into a metabolic syndrome that ma y increase the risk of dementia. The objective of the present study was to assess the long-term association between clustered metabolic cardiovascular risk factors measured at middle age and the risk of dementia in old age. T his prospective cohort study of cardiovascular disease was started in 1965 and was extended to a study of dementia in 1991. The subjects were Japanese -American men with an average age of 52.7+/-4.7 (mean+/-SD) years at baseli ne. Dementia was diagnosed in 215 men, according to international criteria, and was based on a clinical examination, neuropsychological testing, and a n informant interview. The z scores were calculated for 7 risk factors (ran dom postload glucose, diastolic and systolic blood pressures, body mass ind ex, subscapular skinfold thickness, random triglycerides, and total cholest erol). The relative risk (RR [95% CI]) of dementia (subtypes) per 1 SD incr ease in the sum of the z scores was assessed after adjustment for age, educ ation, occupation, alcohol consumption, cigarette smoking, and years of chi ldhood lived in Japan. The z-score sum was higher in demented subjects than in nondemented subjects, indicating a higher risk factor burden (0.74 vers us -0.06, respectively; P=0.008). Per SD increase in the z-score sum, the r isk of dementia was increased by 5% (RR 1.05, 95% CI 1.02 to 1.09), The z-s core sum was specifically associated with vascular dementia (RR 1.11, 95% C I 1.05 to 1.18) but not with Alzheimer's disease (RR 1.00, 95% CI 0.94 to 1 .05). Clustering of metabolic cardiovascular risk factors increases the ris k of dementia (mainly, dementia of vascular origin).