Midlife cardiovascular risk factors and brain morphology in identical older male twins

Objective: Structural changes in the human brain have been reported to a gr eater extent in subjects with cardiovascular risk factors. We conducted a m atched co-twin analysis of elderly monozygotic twins from the National Hear t, Lung, and Blood Institute Twin Study to examine the association between midlife cardiovascular risk factors and MRI-based measures of brain atrophy . Methods: Brain MRIs (1.5-T) were obtained from 74 monozygotic, white, mal e, World War II Veteran twins born in the United States from 1917 to 1927 a nd age 68 to 79 at the time of the brain scan. A semiautomated algorithm wa s used to segment brain images into total brain, CSF, and white matter hype rintensity volumes. Cardiovascular risk factors, medical history variables, and health practices were available from data collected over 25 years of a dult life. Results: Independent of shared genetic or familial influences, w ithin-pair differences in midlife glucose levels, high-density lipoprotein cholesterol, and systolic blood pressure were significantly associated with differences in white matter hyperintensities. Within-pair differences in c oronary heart disease history and in current consumption of alcohol and lev el of physical activity were significantly associated with differences in b rain parenchyma. In addition, within-pair differences in white matter hyper intensity volumes were significantly associated with differences in perform ance on cognitive and physical function tests and self-reports of depressio n symptoms. Conclusion: Independent of age effects and shared genetic or fa milial influences, midlife cardiovascular risk factors and lifetime health practices were predictive of structural brain changes in old age.