Association of plasma beta-amyloid level and cognitive reserve with subsequent XXXX .

@entity1 @entity6 @entity2204 @entity303 @entity73
CONTEXT: Lower plasma b-amyloid 42 and 42/40 levels have been associated with incident @entity303 , but results are conflicting and few have investigated @entity73 among elders without @entity303 . OBJECTIVE: To determine if plasma b-amyloid is associated with @entity73 and if this association is modified by measures of cognitive reserve. DESIGN, SETTING, AND @entity1 : We studied 997 black and white community-dwelling older adults from Memphis, Tennessee, and Pittsburgh, Pennsylvania, who were enrolled in the Health ABC Study, a prospective observational study begun in 1997-1998 with 10-year follow-up in 2006-2007. @entity1 mean age was 74.0 (SD, 3.0) years; 55.2% (n = 550) were female; and 54.0% (n = 538) were black. MAIN OUTCOME MEASURES: Association of near-baseline plasma b-amyloid levels (42 and 42/40 measured in 2010) and repeatedly measured Modified Mini-Mental State Examination (3MS) results. RESULTS: Low b-amyloid 42/40 level was associated with greater 9-year 3MS @entity73 (lowest b-amyloid tertile: mean change in 3MS score, -6.59 [95% confidence interval [CI], -5.21 to -7.67] points; middle tertile: -6.16 [95% CI, -4.92 to -7.32] points; and highest tertile: -3.60 [95% CI, -2.27 to -4.73] points; P < .001). Results were similar after multivariate adjustment for age, race, education, @entity6 , smoking, and @entity2204 [ @entity2204 ] e4 status and after excluding the 72 @entity1 with incident @entity303 . Measures of cognitive reserve modified this association whereby among those with high reserve (at least a high school diploma, higher than sixth-grade literacy, or no @entity2204 e4 allele), b-amyloid 42/40 was less associated with multivariate adjusted 9-year decline. For example, among @entity1 with less than a high school diploma, the 3MS score decline was -8.94 (95% CI, -6.94 to -10.94) for the lowest tertile compared with -4.45 (95% CI, -2.31 to -6.59) for the highest tertile, but for those with at least a high school diploma, 3MS score decline was -4.60 (95% CI,-3.07 to -6.13) for the lowest tertile and -2.88 (95% CI,-1.41 to -4.35) for the highest tertile (P = .004 for interaction). Interactions were also observed for literacy (P = .005) and for @entity2204 e4 allele (P = .02). CONCLUSION: Lower plasma b-amyloid 42/40 is associated with greater @entity73 among elderly @entity1 without @entity303 over 9 years, and this association is stronger among those with low measures of cognitive reserve.
