Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 76 Page 77 Page 78 Page 79 Page 80 Page 81 Page 82 Page 83 Page 84 Page 85 Page 86 Page 87 Page 88 Page 89 Page 90 Page 91 Page 92 Page 93 Page 94 Page 95 Page 96 Page 97 Page 98 Page 99 Page 100 Page 101 Page 102 Page 103 Page 104 Page 105 Page 106 Page 107 Page 108AGING IN THE 21S T CENTURY 38 impairment without dementia (CIND), and nor- mal cognitive functioning. These data can now be used for validation studies and to develop predicted probabilities of dementia and CIND in the HRS (Langa et al. 2005). One report demonstrates how diagnostic data from ADAMS can be used to develop methods for classifying HRS respondents in the same diagnostic categories on the basis of cognitive measures available in the larger sur- vey (Crimmins et al. 2011). Overall, the cogni- tive tests in the HRS predict dementia cases in 74% of the sample who could answer questions for themselves. Not surprisingly, classification of CIND was not as high. Dementia Prevalence As the US population becomes older in the decades ahead, we can expect a large growth in the number of people with AD and dementia, simply because the risk for these conditions is so much higher as we age. Some have called this a looming “dementia epidemic.” Figure 2-1 shows higher rates of dementia in older age groups. For example, in 2012, dementia affects 3% of those aged 65 to 74 compared to 30% for those aged 85 and older.   Through a combination of factors like education and better medical treatment for conditions that affect dementia risk, rates of dementia are slowly trending downward, as Figure 2-1 also shows. In the youngest group, those aged 65 to 74, the percentage with dementia moves steadily from 5% in 1998 to 3% in 2012. The next oldest group, those aged 75 to 84, experienced even larger de- clines, from 14% in 1998 to 10% in 2012. 0% 5% 10% 15% 20% 25% 30% 35% 1998 2000 2002 2004 2006 2008 2010 2012 65-74 Demented aged: 75-84 85+ FIGURE 2-1  Trends in dementia prevalence by age: 1992-2012 Source: HRS 1998-2012.