Background: Low levels of cerebrospinal fluid (CSF) β-amyloid 1-42 (Aβ42) and high total tau (T-tau) are diagnostic for manifest Alzheimer’s disease. It is not known however, whether these biomarkers may be risk indicators for cognitive decline in otherwise healthy elderly.
Methods: We investigated the longitudinal relationship between CSF markers, β-amyloid 1-42 (Aβ42) and total tau (T-tau), measured in 1992, and change in Mini-Mental State Examination (ΔMMSE) score between 1992 and 2000-2002. This was accomplished in 55 women (age 70-84 years, mean MMSE score = 28.3 +/- 1.5), who were participants in the Prospective Population Study of Women in Gothenburg, Sweden. These women were not demented when they experienced lumbar puncture in 1992.
Results: Over the 8-year follow-up period, ΔMMSE (range= +3 to -21 points) was correlated with Aβ42 (Spearman’s r=0.404, p=0.002), such that lower levels of Aβ42 were related to greater decline. This was also observed after excluding 4 women who developed dementia between 1992 and 2002 (Spearman’s r=0.338, p=0.019). A multivariate logistic regression model predicting decline of 5 or more points on the MMSE (observed in 6 women) or becoming demented over the 8 year follow-up period (observed in 4 women), and including age, education, Aβ42, and T-tau, and showed that Aβ42 was the sole predictor of significant cognitive decline or dementia (OR per 100 pg/ml=2.24 95% CI 1.19-4.22, p=0.013).
Conclusions: Low levels of CSF Aβ42 may predict cognitive decline among elderly women without dementia.
- amyloid-beta protein
- biological marker