Table 1.
Participant characteristics and mean and standard deviation for study variables
| Total (n = 361) | Mild ID (n = 187) | Moderate ID (n = 140) | Severe/Profound ID (n = 34) | F or χ2 value (p) | |
| Trisomy type, No. (%) | 10.902 (0.028) | ||||
| Full | 306 (84.8) | 160 (85.5) | 120 (85.7) | 26 (76.5) | |
| Mosaic | 17 (5.5) | 9 (4.8) | 7 (5.0) | 1 (2.9) | |
| Translocation | 19 (5.2) | 8 (4.2) | 5 (3.6) | 6 (17.6) | |
| Unknown | 19 (5.2) | 10 (5.3) | 8 (5.7) | 1 (2.9) | |
| APOE ɛ4, No. (%) | 87 (24.1) | 47 (25.1%) | 29 (20.7%) | 11 (32.4%) | 1.732 (0.421) |
| Age in years, M (SD) | 45.19 (9.88) | 44.89 (9.42) | 45.92 (9.96) | 43.88 (11.93) | 1.593 (0.205) |
| Sex, No. (%) | 4.746 (0.093) | ||||
| Male | 199 (55.1) | 96 (51.3) | 87 (62.1) | 16 (47.1) | |
| Female | 162 (44.9) | 91 (48.7) | 53 (37.9) | 18 (52.9) | |
| Clinical Status, No. (%) | 7.310 (0.120) | ||||
| CS | 263 (72.9) | 144 (77.0) | 93 (66.4) | 26 (76.5) | |
| MCI-DS | 53 (14.7) | 22 (11.8) | 28 (20.0) | 3 (8.8) | |
| Dementia | 45 (12.5) | 21 (11.2) | 19 (13.6) | 5 (14.7) | |
| Race, No. (%) | 2.364 (0.307) | ||||
| White | 340 (94.2) | 179 (95.7) | 129 (92.1) | 32 (94.1) | |
| Non-white | 21 (5.8) | 8 (4.3) | 11 (7.9) | 2 (5.9) | |
| Cholinesterase inhibitors, NO. (%) | 35 (9.6%) | 16 (8.6%) | 13 (9.3%) | 5 (14.7) | 0.829 (0.661) |
| Cognition, M (SD) | |||||
| Block Design | 22.16 (12.38) | 26.33 (12.14) | 18.74 (11.24) | 12.26 (7.78) | 28.223 (<0.001) |
| mCRT | 27.31 (10.66) | 29.17 (9.83) | 25.26 (11.34) | 24.07 (10.71) | 5.639 (0.004) |
| DSMSE | 59.27 (15.79) | 65.77 (13.23) | 53.96 (14.95) | 43.23 (13.63) | 48.887(<0.001) |
| DLD Cognitive | 7.10 (9.22) | 4.02 (6.56) | 9.30 (10.06) | 14.94 (10.99) | 29.208 (<0.001) |
| DLD Social | 6.27 (6.93) | 4.97 (5.66) | 7.31 (7.46) | 9.21 (9.25) | 8.510 (<0.001) |
| Biomarkers, M (SD) | |||||
| PET Aβ | 16.23 (28.70) | 17.46 (31.51) | 15.82 (26.56) | 11.63 (19.59) | 0.812 (0.446) |
| Tau PET | 1.19 (0.26) | 1.20 (0.29) | 1.21 (0.08) | 1.12 (0.08) | 0.943 (0.323) |
M, mean; SD, standard deviation; ID, intellectual disability; CS, cognitively stable; MCI-DS, mild cognitive impairment-Down syndrome; mCRT, modified Cued Recall Test; DSMSE, Down Syndrome Mental Status Examination; DLD, The Dementia Questionnaire for People with Learning Disabilities. PET Aβ is in centiloids. Tau PET is in standard uptake value ratio.