Midlife cardiovascular risk factors and late cognitive impairment.

Cardiovascular risk factors increase the risk of dementia in later life. The aims of the current study were to assess the effect of multiple midlife cardiovascular risk factors on the risk of cognitive impairment in later life, and to assess the validity of the previously suggested CAIDE Study risk score predicting dementia risk 20 years later. A total of 2,165 Finnish twins were followed and at the end of the follow-up their cognitive status was assessed with a validated telephone interview. The assessment of the risk factors at baseline was based on a self-report questionnaire. Relative risk ratios (RR) were calculated and receiver operating characteristic analyses performed. Midlife obesity (RR 2.42, 95 % CI 1.47-3.98), hypertension (RR 1.38, 95 % CI 1.01-1.88) and low leisure time physical activity (RR 2.52, 95 % CI 1.10-5.76) increased the risk of cognitive impairment after a mean follow-up of 22.6 ± 2.3 years. Hypercholesterolemia did not significantly increase the risk (RR 1.52, 95 % CI 0.92-2.51). Overweight individuals who gained more than 10 % weight between 1981 and 1990 had an increased risk of cognitive impairment (RR 4.27, 95 % CI 1.62-11.2). The CAIDE Study risk score combining various individual risk factors had an area-under-curve of 0.74 (95 % CI 0.69-0.79, n = 591), and there was a strong association between an increasing risk score and the risk of cognitive impairment. The results indicate that multiple midlife cardiovascular risk factors increase the risk of cognitive impairment in later life. Also, a risk score including easily measurable midlife factors predicts an individual's cognitive impairment risk well.