Table 4.
Relationship between month of the year (x) and serum concentrations of 25(OH)D (y in nmol/L), stating the month as an integer. January: 1, February: 2, etc. The time of the year at which the highest concentration of 25(OH)D in serum is found, is expressed as month in the year. Mathematical modeling on the data from the NDNS database.
| Cohort | Gender | n | Formula | Peak Concentration Reached at |
|---|---|---|---|---|
| 4–10 | males | 93 | y = −0.76x2 + 10.97x + 22.71 | 7.2 |
| 4–10 | females | 74 | y = −0.43x2 + 7.80x + 24.08 | 9.1 |
| 11–18 | males | 169 | y = −0.86x2 + 13.13x + 7.49 | 7.6 |
| 11–18 | females | 142 | y = −0.46x2 + 6.94x + 23.09 | 7.5 |
| 19–64 | males | 333 | y = −0.65x2 + 10.58x + 10.38 | 8.1 |
| 19–64 | females | 455 | y = −0.53x2 + 8.35x + 21.16 | 7.9 |
| 65–90 | males | 90 | y = −0.34x2 + 5.25x + 30.68 | 7.7 |
| 65–94 | females | 111 | y = −0.47x2 + 6.87x + 23.14 | 7.3 |
| Overall | males + females | 1467 | y = −0.52x2 + 8.36x + 20.65 | 8.1 |