Table 2.
Vitamin D Status by Cognitive Diagnosis
| Vitamin D Level | Cognitive Diagnosis | ||
|---|---|---|---|
| Cognitively Normal (n = 189) | MCI (n = 125) | Dementia (n = 67) | |
| Serum 25-OHD level, mean (SD), ng/mL | 19.7 (13.1) | 20.0 (10.3) | 16.2 (9.4)a |
| Vitamin D status, No. (%)b | |||
| Deficient, <12 ng/mL | 46 (24.3) | 30 (24.0) | 24 (35.8) |
| Insufficient, 12 to <20 ng/mL | 66 (34.9) | 41 (32.8) | 27 (40.3) |
| Adequate, 20 to <50 ng/mL | 74 (39.2) | 53 (42.4) | 15 (22.4) |
| High, ≥50 ng/mL | 3 (1.6) | 1 (0.8) | 1 (1.5) |
Abbreviations: MCI, mild cognitive impairment; 25-OHD, 25-hydroxyvitamin D.
SI conversion factor: To convert 25-OHD to nanomoles per liter, multiply by 2.496.
a
Mean of 25-OHD level in the dementia group was significantly lower than the cognitively normal and MCI groups. Data were analyzed on the logarithmic scale: overall group difference, P = .006; pairwise differences between the dementia group and the other 2 groups were significant after Tukey honestly significant difference correction for multiple comparisons (P < .05).
b
Vitamin D status categories as defined by the Institute of Medicine based on serum 25-OHD level.1