Table 4.
Linear Mixed Regression Model Selection for IRT-Based CASI Scoresa
| Selected model requiring interactions of language use group, age, and age2 |
Selected model requiring interactions of language use group and age |
|
| Covariate | Coefficient (95% CI) | Coefficient (95% CI) |
| (Intercept) | 78.58 (73.70 to 83.46) | 78.86 (74.04 to 83.70) |
| Examination 1 or 5 language use | ||
| Spoke but did not read Japanese | 0 (reference) | 0 (reference) |
| Neither spoke nor read Japanese | 1.92 (−0.96 to 4.80) | 1.20 (−0.72 to 3.12) |
| Both spoke and read Japanese | 0.09 (−2.75 to 2.94) | −0.56 (−2.47 to 1.35) |
| Age at Examination 4 | 9.41 (5.12 to 13.70) | 9.41 (5.12 to 13.70) |
| Education (y) | 2.90 (2.14 to 3.67) | 2.91 (2.14 to 3.67) |
| Education2 (y) | −0.07 (−0.10 to −0.040) | −0.07 (−0.10 to −0.040) |
| Annual income at Examination 4 ($) | ||
| <15,000 | 0 (reference) | 0 (reference) |
| 15,000–19,999 | 2.16 (0.84 to 3.49) | 2.17 (0.84 to 3.49) |
| 20,000–29,999 | 3.67 (2.40 to 4.93) | 3.67 (2.40 to 4.94) |
| ≥30,000 | 4.60 (3.37 to 5.83) | 4.60 (3.37 to 5.83) |
| Smoking status at Examination 4 | ||
| Never | 0 (reference) | 0 (reference) |
| Past | 1.03 (0.14 to 1.92) | 1.03 (0.13 to 1.92) |
| Current | 0.91 (−0.87 to 2.68) | 0.90 (−0.87 to 2.67) |
| 0 APOE ϵ4 alleles | 0 (reference) | 0 (reference) |
| 1 or 2 APOE ϵ4 alleles | 0.62 (−1.31 to 2.54) | 0.60 (−1.32 to 2.53) |
| No. of test taken | ||
| 1st | 0 (reference) | 0 (reference) |
| 2nd | −1.51 (−2.8 to −0.18) | −1.50 (−2.83 to −0.18) |
| 3rd | −0.84 (−3.42 to 1.74) | −0.84 (−3.42 to 1.74) |
| 4th | 0.47 (−2.79 to 3.74) | 0.46 (−2.80 to 3.73) |
| Age | −11.81 (−17.10 to −6.52) | −12.61 (−17.50 to −7.71) |
| Age2 | −2.02 (−3.64 to −0.40) | −1.59 (−2.82 to −0.37) |
| Age × Examination 1 or 5 language | ||
| Spoke but did not read Japanese | 0 (reference) | 0 (reference) |
| Neither spoke nor read Japanese | −1.52 (−7.712 to 4.67) | 0.44 (−1.44 to 2.32) |
| Both spoke and read Japanese | −1.40 (−7.06 to 4.26) | 0.29 (−1.45 to 2.03) |
| Age × 1 or 2 APOE ϵ4 alleles present | −1.96 (−3.80 to −0.12) | −1.94 (−3.78 to −0.10) |
| Age2 × Examination 1 or 5 language | ||
| Spoke but did not read Japanese | 0 (reference) | |
| Neither spoke nor read Japanese | 1.07 (−2.17 to 4.31) | |
| Both spoke and read Japanese | 0.87 (−1.88 to 3.61) | |
Note: APOE = apolipoprotein E; CASI = Cognitive Abilities Screening Instrument; CI = confidence interval; IRT = item response theory.
a
Age effects are for 10 years, centered at age 70.