Table 1.
Phenotypic Determinants of the 25(OH)D Response to Vitamin D3 Supplementation at 2-Month and 12-Month Follow-up
| (%) | n (%) | 2-Month Follow-up |
12-Month Follow-up |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean Δ25(OH)D (SD) (nmol/L) | Unadjusted Mean Difference (95% CI) | P Value | Adjusted Mean Difference (95% CI)* | P Value | Mean Δ25(OH)D (SD) (nmol/L) | Unadjusted Mean Difference (95% CI) | P Value | Adjusted Mean Difference (95% CI)† | P Value | ||
| Sex | |||||||||||
| M | 90 (48.4) | 12.8 (17.5) | Referent | — | — | — | 23.0 (24.4) | Referent | — | — | — |
| F | 96 (51.6) | 12.4 (26.6) | −0.4 (−7.0 to 6.1) | 0.90 | — | — | 22.8 (32.4) | −0.2 (−8.5 to 8.2) | 0.97 | — | — |
| Age, yr | 186 (100.0) | — | −0.0 (−0.3 to 0.2) | 0.84 | — | — | — | 0.1 (−0.1 to 0.5) | 0.25 | — | — |
| Disease status | |||||||||||
| Control subjects | 19 (10.2) | 23.5 (22.9) | Referent | — | Referent | — | 39.8 (29.8) | Referent | — | Referent | — |
| Asthma | 88 (47.3) | 12.3 (25.4) | −11.2 (−22.4 to −0.0) | 0.05 | −8.00 (−16.3 to 0.4) | 0.06 | 20.9 (27.4) | −18.9 (−33.7 to −4.1) | 0.01 | −20.3 (−32.2 to −8.5) | 0.001 |
| COPD | 79 (42.5) | 10.5 (18.4) | −13.0 (−24.3 to −1.7) | 0.02 | −9.5 (−18.0 to −1.0) | 0.03 | 21.5 (28.9) | −18.3 (−33.2 to −3.4) | 0.02 | −20.3 (−32.2 to −8.4) | 0.001 |
| Ethnic origin | |||||||||||
| White European | 159 (85.5) | 12.1 (22.9) | Referent | — | — | — | 22.1 (29.5) | Referent | — | — | — |
| Other | 27 (14.5) | 16.0 (20.8) | 3.9 (−5.4 to 13.2) | 0.41 | — | — | 27.9 (22.6) | 5.8 (−6.1 to 17.8) | 0.34 | — | — |
| Body mass index, kg/m2 | 186 (100.0) | — | −0.2 (−0.7 to 0.3) | 0.42 | — | — | — | −0.3 (−0.9 to 0.4) | 0.42 | — | — |
| Smoking status | |||||||||||
| Never- or ex-smoker | 140 (75.3) | 13.7 (21.1) | Referent | — | — | — | 23.3 (26.4) | Referent | — | — | — |
| Current smoker | 46 (24.7) | 9.4 (26.8) | −4.4 (−11.9 to 3.2) | 0.26 | — | — | 21.5 (34.7) | −1.9 (−11.5 to 7.8) | 0.71 | — | — |
| Alcohol intake, units/week | 186 (100.0) | — | 0.0 (−0.2 to 0.3) | 0.76 | — | — | — | −0.1 (−0.4 to 0.2) | 0.48 | — | — |
| Month of first dose | |||||||||||
| February–June | 92 (49.5) | 22.1 (21.1) | Referent | — | Referent | — | 26.5 (26.1) | Referent | — | Referent | — |
| July–January | 94 (50.5) | 3.4 (20.1) | −18.8 (−24.7 to −12.8) | <0.001 | −12.8 (−17.8 to −7.8) | <0.001 | 19.3 (30.7) | −7.1 (−15.5 to 1.2) | 0.09 | — | — |
| Days from first dose to follow-up | 186 (100.0) | — | −0.7 (−0.6 to 0.4) | 0.79 | — | — | — | −0.2 (−0.7 to 0.2) | 0.34 | — | — |
| Baseline 25(OH)D, nmol/L | 186 (100.0) | — | −0.5 (−0.6 to −0.4) | <0.001 | −0.5 (−0.6 to −0.4) | <0.001 | — | −0.7 (−0.8 to −0.5) | <0.001 | −0.7 (−0.8 to −0.5) | <0.001 |
Definition of abbreviations: CI = confidence interval; COPD = chronic obstructive pulmonary disease; Δ25(OH)D = change in serum 25-hydroxyvitamin D3 concentration at follow-up versus baseline.
*
Adjusted for disease status, month of first dose, and baseline concentration of 25-hydroxyvitamin D.
†
Adjusted for disease status and baseline concentration of 25-hydroxyvitamin D.