Table 2.
Association Between 25(OH) Vitamin D and Odds of Cognitive Impairment at Baseline and Cognitive Decline
| 25(OH)D categories | Odds Ratio (95% Confidence Interval) | |||||
| Crude Model* | Base Model† | MV Model‡ | Crude Model* | Base Model† | MV Model‡ | |
| Cognitive impairment at baseline by mMMSE | Cognitive impairment at baseline by trails B | |||||
| <10 ng/mL | 1.85 (1.26–2.71) | 1.62 (1.10–2.39) | 1.60 (1.05–2.42) | 1.26 (0.80–1.99) | 1.14 (0.72–1.82) | 1.09 (0.68–1.76) |
| 10–19 ng/mL | 1.29 (0.99–1.69) | 1.13 (0.86–1.49) | 1.09 (0.82–1.44) | 1.43 (1.07–1.92) | 1.24 (0.91–1.67) | 1.23 (0.90–1.68) |
| 20–29 ng/mL | 0.81 (0.62–1.06) | 0.80 (0.60–1.05) | 0.79 (0.60–1.06) | 1.11 (0.83–1.48) | 1.13 (0.84–1.52) | 1.12 (0.82–1.52) |
| ≥30 ng/mL | 1.00 (referent) | 1.00 (referent) | 1.00 (referent) | 1.00 (referent) | 1.00 (referent) | 1.00 (referent) |
| P trend | <.001 | .009 | .029 | .021 | .251 | .314 |
| Cognitive decline by mMMSE§ | Cognitive decline by trails B‖ | |||||
| <10 ng/mL | 1.63 (1.18–2.26) | 1.52 (1.09–2.11) | 1.58 (1.12–2.22) | 1.06 (0.69–1.63) | 1.01 (0.65–1.56) | 1.00 (0.64–1.56) |
| 10–19 ng/mL | 1.34 (1.08–1.66) | 1.24 (1.00–1.54) | 1.31 (1.04–1.64) | 1.01 (0.77–1.32) | 0.95 (0.72–1.24) | 0.93 (0.70–1.23) |
| 20–29 ng/mL | 1.07 (0.87–1.32) | 1.07 (0.87–1.33) | 1.13 (0.91–1.41) | 0.84 (0.65–1.09) | 0.85 (0.66–1.11) | 0.83 (0.64–1.09) |
| ≥30 ng/mL | 1.0 (referent) | 1.0 (referent) | 1.0 (referent) | 1.0 (referent) | 1.0 (referent) | 1.0 (referent) |
| P trend | <.001 | .006 | .003 | .628 | .998 | .931 |
Notes: mMMSE = modified Mini-Mental State Examination MV, Multivariate.
Adjusted for clinic site and season of blood collection for vitamin D measurement.
Adjusted for clinic site, season of blood collection, age at baseline, and years of education.
Adjusted for clinic site, season of blood collection, age at baseline, years of education, self-reported health status, instrumental activity of daily living impairments, smoking status at baseline, body mass index, history of hypertension, history of diabetes and depression, baseline cognitive function (for models of cognitive decline only), walking for exercise, and baseline vitamin D supplementation.
Cognitive decline at follow-up defined as >1 SD (2.9 points) below the mean difference between baseline and follow-up at Year 10 examination (or Year 8 if Year 10 examination was not performed).
Cognitive decline at follow-up defined as >1 SD (87.3 s) above the mean difference in time to completion of Trails B testing between baseline and follow-up.