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Table 4 Serum 25(OH)D in relation to calcium and vitamin D intakes in all subjects and gender specific in 1917 subjects in the sub-study

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

86

59.4 (55.4, 63.5)

230

60.4 (57.9, 62.9)

125

63.8 (60.2, 67.4)

53

69.3 (62.2, 76.4)##*

  7.0–13.9

44

61.7 (55.3, 68.1)

225

66.2 (63.4, 69.1)

236

66.2 (63.6, 68.8)

119

65.3 (62.0, 68.6)

  14.0–20.9

15

81.6 (70.3, 92.8)

85

75.1 (69.9, 80.2)

130

71.2 (67.7, 74.7)

104

67.8 (64.1, 71.4)#*

   > 20.9

16

81.1 (68.0, 94.2)†

143

74.5 (71.3, 77.6)†

151

76.6 (73.5, 79.8)†

155

75.4 (72.4, 78.5)†

 Males‡

 Vitamin D intake (ug/d)§

   < 7.0

28

58.7 (51.2, 65.5)

92

59.4 (55.7, 63.1)

44

57.8 (53.1, 62.6)

19

54.6 (45.9, 63.2)

  7.0–13.9

21

56.6 (46.6, 66.6)

103

63.3 (59.4, 67.1)

107

63.8 (60.0, 67.6)

66

61.8 (57.4, 66.2)

  14.0–20.9

4

76.6 (50.1, 103.0)

33

74.4 (64.2, 84.6)

56

67.1 (62.4, 71.8)

50

61.6 (56.3, 66.9)#*

   > 20.9

4

81.8 (35.2, 128.5)

68

75.7 (70.6, 80.8)†

62

75.2 (70.9, 79.4)†

71

71.0 (67.3, 74.7)†

Females‡

 Vitamin D intake (ug/d)§

   < 7.0

58

59.8 (54.6, 64.9)

138

61.1 (57.8, 64.4)

81

67.1 (62.2, 71.9)

34

77.5 (68.5, 86.6)##**

  7.0–13.9

23

66.3 (58.0, 74.7)

122

68.7 (64.6, 72.8)

129

68.2 (64.7, 71.7)

53

69.7 (64.7, 74.7)

  14.0–20.9

11

83.4 (68.7, 98.1)

52

75.5 (69.7, 81.2)

74

74.3 (69.3, 79.3)

54

73.4 (68.7, 78.2)

   > 20.9

12

80.9 (65.4, 96.3)†

75

73.3 (69.4, 77.3)†

89

77.7 (73.2, 82.2)†

84

79.2 (74.6, 83.7)

  1. #P < 0.05, ## < 0.01. Linear trend for serum 25(OH)D across calcium D 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, not taking solarium regularly, with valid serum PTH measurement, and with serum calcium < 2.51 mmol/L
  5. § Including supplements
  6. The data are mean (95% CI). The P values are adjusted for multiple testing with a factor of 4