TABLE 3.
Hazard ratios (95% CIs) for combined 4.5-y incidence of dementia or cognitive impairment without dementia for each covariate with age at diagnosis or censoring as a time factor1
| Bivariate model (model 1) (n = 95) | Model 2 (n = 80) | Model 3 (n = 80) | Model 4 (n = 66) | |
|---|---|---|---|---|
| Homocysteine2 | 1.58 (1.88, 2.83) | 2.45 (1.26, 4.75) | 1.85 (0.93, 3.70) | 2.39 (1.11, 5.16) |
| Plasma vitamin B-123 | 1.04 (1.01, 1.08) | 1.06 (1.02, 1.10) | 1.05 (1.10, 1.09) | 1.07 (1.02, 1.11) |
| RBC folate2 | 0.85 (0.57, 1.24) | —4 | — | — |
| Glomerular filtration rate2 | 0.93 (0.57, 1.50) | — | — | — |
| Baseline stroke (0, 1)5 | 2.93 (1.76, 4.86) | — | 2.53 (1.43, 4.45) | — |
| Education (y) | 0.94 (0.90, 0.98) | — | 0.94 (0.90, 0.99) | 0.95 (0.91, 1.00) |
| Sex (female versus male) | 1.14 (0.76, 1.70) | — | — | — |
| Birthplace (Mexico versus USA) | 0.93 (0.62, 1.40) | — | — | — |
| Multivitamins with vitamin B (0, 1)5 | 0.94 (0.64, 1.48) | — | — | — |
| Only B vitamins (0, 1)5 | 0.30 (0.07, 1.26) | — | — | — |
| Other vitamins (0, 1)5 | 1.19 (0.78, 1.81) | — | — | — |
RBC, red blood cell. Except for homocysteine, covariates were retained in the model only if they were associated with the outcome and influenced the hazard ratio. Bivariate model, unadjusted coefficients from separate models; model 2, simultaneous adjustment for all biomarkers; model 3, model 2 + age, education, baseline stroke, and sex; model 4, model 3 excluding baseline stroke. The total sample available for analysis after exclusions and missing data on biomarkers was n = 1519, 1332, 1332, and 1235 for bivariate model and models 2, 3, and 4, respectively.
Square root.
Natural log.
The covariate was not included in the model (all such).
0 = absent, 1 = present.