Prospective association of 25(OH)D3, 25(OH)D2, phosphate, calcium and PTH concentrations (assessed at mean age of 9.8 years) with key stage 4 educational attainment (age 15–16 years) (n=3171)
| Exposure | Outcome | OR per doubling of exposure (95% CI) | ||
| Model 1 | Model 2 | Model 3 | ||
| 25(OH)D3 | Achieved 5 or more A*–C grades | 1.04 (0.98 to 1.10) | 1.03 (0.97 to 1.09) | 1.03 (0.97 to 1.09) |
| Achieved 9 or more A*–A grades | 0.99 (0.91 to 1.07) | 0.99 (0.92 to 1.08) | 0.99 (0.90 to 1.08) | |
| Did not achieve any A*–C grades | 0.96 (0.88 to 1.05) | 0.98 (0.89 to 1.09) | 0.98 (0.89 to 1.08) | |
| 25(OH)D2 | Achieved 5 or more A*–C grades | 0.89 (0.82 to 0.98) | 0.91 (0.82 to 1.00) | 0.90 (0.82 to 1.00) |
| Achieved 9 or more A*–A grades | 0.81 (0.70 to 0.91) | 0.84 (0.74 to 0.96) | 0.84 (0.73 to 0.97) | |
| Did not achieve any A*–C grades | 1.16 (1.02 to 1.34) | 1.12 (0.96 to 1.29) | 1.12 (0.96 to 1.30) | |
| Albumin-adjusted calcium | Achieved 5 or more A*–C grades | 1.00 (0.95 to 1.05) | 1.03 (0.98 to 1.09) | 1.02 (0.96 to 1.08) |
| Achieved 9 or more A*–A grades | 0.97 (0.90 to 1.04) | 1.00 (0.93 to 1.08) | 1.01 (0.94 to 1.10) | |
| Did not achieve any A*–C grades | 1.01 (0.93 to 1.09) | 0.97 (0.88 to 1.06) | 0.94 (0.85 to 1.03) | |
| Phosphate | Achieved 5 or more A*–C grades | 1.06 (1.01 to 1.12) | 1.05 (1.00 to 1.11) | 1.05 (0.99 to 1.11) |
| Achieved 9 or more A*–A grades | 1.00 (0.93 to 1.08) | 0.98 (0.90 to 1.05) | 0.97 (0.90 to 1.06) | |
| Did not achieve any A*–C grades | 1.06 (0.97 to 1.15) | 1.07 (0.98 to 1.16) | 1.08 (0.99 to 1.19) | |
| Parathyroid hormone | Achieved 5 or more A*–C grades | 1.00 (0.95 to 1.05) | 1.00 (0.95 to 1.06) | 1.00 (0.94 to 1.06) |
| Achieved 9 or more A*–A grades | 0.97 (0.90 to 1.05) | 0.95 (0.88 to 1.04) | 0.96 (0.88 to 1.05) | |
| Did not achieve any A*–C grades | 1.02 (0.94 to 1.11) | 1.03 (0.94 to 1.14) | 1.02 (0.92 to 1.13) | |
Model 1 is unadjusted (the exposures are standardised for age and gender and 25(OH)D3 is adjusted for season and ethnicity).
Model 2 same as model 1 plus adjustment for ethnicity, head of household social class, mothers and partners education, time spent outdoors during summer (age 8.5 years), use of sunblock, hat, covering clothing, avoidance of midday sun, body mass index and eligibility for free school meals.
Model 3 same as model 2 plus adjustment for serum concentrations of other hormones/metabolites, which are related 25(OH)D3 homeostasis (eg, association of 25(OH)D3 is adjusted for 25(OH)D2, phosphate, albumin-adjusted calcium and parathyroid hormone).