WHITE-MATTER HYPERINTENSITIES ON MRI IN THE NEUROLOGICALLY NONDISEASED ELDERLY - ANALYSIS OF COHORTS OF CONSECUTIVE SUBJECTS AGED 55 TO 85 YEARS LIVING AT HOME

Background and Purpose We undertook this study to evaluate the frequen cy and risk factors of white matter Hyperintensities seen on T-2-weigh ted MR imaging. We examined cohorts of neurologically nondiseased elde rly subjects participating in a general-community study, the Helsinki (Finland) Aging Brain Study. Cohorts of consecutive subjects aged 55, 60, 65, 70, 75, 80, and 85 years (n=20, 18, 20, 18, 19, 18, and 15, re spectively; total, n=128) were divided into a young-old (age <75 years , n=76) group and an old-old (age greater than or equal to 75 years, n =52) group. Methods Frequency of hyperintensities seen on T-2-weighted axial and coronal MR images (0.02 T) was rated using a four-point sca le in periventricular and centrum semiovale areas. Results The majorit y of the subjects showed only mild white matter hyperintensities, whic h were more frequent in the periventricular areas. Age was the most im portant factor to explain the presence of hyperintensities. A logistic regression analysis related periventricular hyperintensities in the e ntire group to central atrophy (odds ratio [OR], 4.7; 95% confidence i nterval [CI], 1.7 to 12.9) and silent infarcts (OR, 5.6; 95% CI, 1.0 t o 19.8); among the young-old, hyperintensities related to diabetes (OR , 17.0; 95% CI, 1.9 to 154.2) and central atrophy (OR, 14.7; 95% CI, 3 .5 to 61.8). Centrum semiovale hyperintensities related in the entire group to cardiac arrhythmia (OR, 4.0; 95% CI, 1.0 to 15.5), central at rophy (OR, 3.9; 95% CI, 1.2 to 12.4), and silent infarcts (OR, 3.6; 95 % CI, 1.0 to 12.5). Conclusions These mild white matter hyperintensiti es in the neurologically nondiseased elderly related especially to age and also to concomitant silent infarcts, atrophy, and some vascular r isk factors. The known factors, however, explained only part of the va riation. The young-old and old-old groups showed different association s. In contrast to former assumptions, the presence of white matter hyp erintensities among the aged is likely to be linked to other as yet un identified age-related factors.