Table 2.

Plasma 25(OH)D concentrations, season of blood draw, and vitamin D intake from foods and supplements at Osteoporosis and Periodontal Disease (OsteoPerio) Study baseline (1997–2000) and follow-up (2002–2005) among women with plasma 25(OH)D concentrations at both time points (n = 672)

BaselineFollow-up
Plasma 25(OH)D concentrations (nmol/L), mean ± SD60.0 ± 22.267.8 ± 22.2a
Plasma 25(OH)D concentrations (nmol/L), range5.9–147.213.0–185.8
Clinical 25(OH)D levels, n (%)
 At risk for deficiency (<30 nmol/L)58 (8.6)22 (3.7)a
 At risk for inadequacy (≥30–<50 nmol/L)157 (23.4)108 (16.1)
 Adequate (≥50–<75 nmol/L)305 (45.4)317 (47.2)
 Adequate (≥75 nmol/L)152 (22.6)225 (33.5)
Season of blood draw, n (%)
 January–March143 (21.3)160 (23.8)a
 April–June163 (24.3)180 (26.8)
 July–September182 (27.1)168 (25.0)
 October–December184 (27.4)164 (24.4)
Vitamin D intake from foods (IU/d), mean ± SD200.5 ± 130.3246.4 ± 245.2a
Vitamin D supplement usage, n (%)
 None189 (28.1)72 (10.7)a
 ≤400 IU/d324 (48.2)237 (35.3)
 >400 IU/d159 (23.7)359 (53.4)
 N Missing04 (0.6)
Total vitamin D intake from foods and supplements (IU/d), mean ± SD536.9 ± 319.7775.7 ± 439.1a
  • aP value less than 0.05 for paired t test when comparing means of continuous variables or Bowker test of symmetry when comparing proportions of categorical variables at baseline versus follow-up.