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Table 2 Serum 25(OH)D in relation to calcium and vitamin D intakes in all subjects and gender specific in the 11,250 subjects in the main cohort

From: Increased calcium intake is associated lower serum 25-hydroxyvitamin D levels in subjects with adequate vitamin D intake: a population-based observational study

  Calcium intake§ < 500 mg/d Calcium intake§ 500–999 mg/d Calcium intake§ 1000–1499 mg/d Calcium intake§ > 1499 mg/d
n Serum 25(OH)D (nmol/L) n Serum 25(OH)D (nmol/L) n Serum 25(OH)D (nmol/L) n Serum 25(OH)D (nmol/L)
All subjects‡
 Vitamin D intake (ug/d)§
   < 7.0 444 56.2 (54.3, 58.0) 1396 54.8 (53.8, 56.7) 874 56.7 (55.2, 58.1) 302 56.7 (54.3, 59.1)
  7.0–13.9 223 60.8 (58.1, 63.5) 1360 60.8 (59.8, 61.9) 1531 59.7 (58.7, 60.6) 943 57.8 (56.5, 59.0)#
  14.0–20.9 69 69.1 (64.0, 74.1) 513 69.0 (67.3, 70.8) 624 66.6 (65.0, 68.2) 553 62.5 (60.8, 64.2)#**
   > 20.9 77 76.2 (71.1, 81.2)† 666 74.3 (72.7, 76.0)† 871 72.5 (71.2, 73.8)† 804 69.6 (68.2, 71.1)#**†
Males‡
 Vitamin D intake (ug/d)§
   < 7.0 165 54.5 (51.7, 57.3) 530 52.3 (50.7, 53.9) 363 52.3 (50.3, 54.2) 139 49.8 (47.1, 52.6)
  7.0–13.9 93 57.3 (53.0, 61.6) 635 57.3 (55.8, 58.8) 815 56.8 (55.6, 58.1) 536 54.4 (52.8, 56.0)
  14.0–20.9 29 62.5 (57.4, 67.7) 208 66.6 (63.7, 69.5) 284 62.6 (60.5, 64.7) 321 59.0 (56.9, 61.1)#**
   > 20.9 32 77.7 (68.9, 86.5)† 286 72.3 (69.9, 74.6)† 401 70.5 (68.7, 72.4)† 431 65.9 (64.1, 67.7)#**†
Females‡
 Vitamin D intake (ug/d)§
   < 7.0 279 57.2 (54.7, 59.7) 866 56.4 (55.0, 57.7) 511 59.8 (57.8, 61.8) 163 62.6 (59.1, 66.2)#*
  7.0–13.9 130 63.4 (59.9, 66.8) 725 64.0 (62.5, 65.5) 716 62.9 (61.5, 64.4) 407 62.2 (60.4, 64.1)
  14.0–20.9 40 73.9 (66.2, 81.6) 305 70.7 (68.5, 73.0) 340 70.0 (67.6, 72.3) 232 67.4 (64.6, 70.2)
   > 20.9 45 75.1 (68.9, 81.4)† 380 75.9 (73.7, 78.1)† 470 74.2 (72.4, 76.0)† 373 73.9 (71.8, 76.1)†
  1. #P < 0.01. Linear trend for serum 25(OH)D across calcium intake groups without adjustments
  2. *P < 0.05, **P < 0.01. Linear trend for serum 25(OH)D across calcium intake groups with sex, age, BMI and month of blood sampling (using dummy variables) as covariates
  3. P < 0.001. Linear trend for serum 25(OH)D across vitamin D intake groups without adjustments as well as with sex, age, BMI and month of blood sampling (using dummy variables) as covariates
  4. ‡ Subjects in the Tromsø study with valid food frequency questionnaires, serum 25(OH)D measurement, not been on a sunny vacation last 2 months, and not taking solarium regularly
  5. §Including supplements
  6. The data are mean (95% CI). The P values are adjusted for multiple testing with a factor of 4