Asymptomatic Cerebral White Matter Lesions Predict Future Cognitive Decline in Japanese Elderly
METHODS: The data were derived from the National Institute for Longevity Sciences – Longitudinal Study of Aging (NILS-LSA). The subjects were 597 men and women, who were the participants in the 2nd wave examination (baseline), aged 65 and over, did not have dementia (Mini-mental State Examination, MMSE>=24) nor cerebrovascular diseases at that time, and attended at the sequence of biannual examinations (the 3rd, 4th, 5th, 6th and 7th wave examinations), at least one time. WMLs with no obvious CVD on brain MRI were classified into 3 categories (normal/mild/moderate or severe) . The influences of WMLs at baseline and time from baseline on cognitive dysfunction (MMSE <=23) for maximum 10 years were estimated by generalized linear model, adjusted for age, sex (Model 1), plus education, smoking habit and diseases (diabetes, hypertension, dyslipidemia and heart diseases) (Model 2). A p value <0.05 was considerd as statistically significant.
RESULTS: The average number of attendance at the follow-up examinations was 3.40 (s.d. 1.57) and the latest average of follow-up periods was 7.20 (s.d. 3.16) years. In the model 1, the odds ratios of moderate or severe WMLs by normal were 2.77 (95% confidence interval: 1.39 - 5.51). As for mild WMLs by normal, the odds ratio was 1.92 (0.99 - 3.72), that was not significant but marginal. After adjusting for more covariates (Model 2), the odds ratios were 2.88 (1.42 - 5.82) and 2.05 (1.02 - 4.11), respectively.
CONCLUSIONS: Asymptomatic WMLs, including initial mild lesions, might predict future cognitive decline in the elderly.