Table 3 Distribution of continuous variables of interest in the study population (20–50 year old nonsmokers)

Participant characteristics

 Age (years)

36.4 (0.32)

36.5

14.4

21.2, 48.8

 BMI

28.4 (0.22)

27.7

8.1

19.8, 39.1

 Systolic BP (mm Hg)

117.9 (0.54)

115.5

16.9

96.9, 140.8

 Diastolic BP (mm Hg)

72.0 (0.48)

70.9

15.2

52.8, 91.5

 PIR

3.3 (0.08)

3.4

3.1

0.6, 5.0

Clinical indicators

 Vitamin D (ng/mL)

23.8 (0.45)

21.9 (21.0, 23.0)

22.7

11

8.90, 38.5

5

0.21

 Vitamin C (mg/dL)

0.98 (0.02)

0.85 (0.81, 0.89)

0.98

0.56

0.24, 1.70

0.012

0

 Total calcium (mg/dL)

9.50 (0.02)

9.49 (9.46, 9.53)

9.45

0.43

8.93, 9.96

2

0

 Glucose, Serum (mg/dL)

92.4 (0.67)

90.5 (89.4, 91.5)

88.1

13.1

73.6, 117.0

3

0

 Direct HDL-Cholesterol (mg/dL)

54.1 (0.54)

52.1 (51.1, 53.1)

51.3

20.5

33.5, 80.9

^a

 CRP (mg/dL)

0.43 (0.04)

0.17 (0.15, 0.18)

0.15

0.34

0.02, 1.41

0.02

2.8

Iron markers

 Transferrin receptor (mg/L)

3.81 (0.06)

3.60 (3.51, 3.68)

3.4

1.4

2.11, 6.36

 Ferritin (ng/mL)

56.98 (2.77)

37.14 (34.96, 39.46)

39.2

45

5.65, 177.5

 Hematocrit (%)

42.4 (0.16)

42.2 (41.9, 42.5)

42.4

6.3

35.5, 49.4

 Hemoglobin (g/dL)

14.4 (0.05)

14.3 (14.2, 14.4)

14.4

2

11.8, 16.8

 Mean cell hemoglobin (pg)

30.2 (0.10)

30.1 (29.9, 30.3)

30.4

2.3

26.6, 32.7

 MCHC (g/dL)

33.9 (0.07)

33.9 (33.8, 34.0)

33.8

1

32.4, 35.1

 Protoporphyrin (μg/dL RBC)

64.6 (1.51)

58.2 (56.6, 59.9)

53.2

26

34.0, 126.6

 Iron, Frozen serum (μg/dL)

76.8 (1.47)

68.8 (66.5, 71.2)

71.5

46

28.5, 134.2

 TIBC, Frozen serum (μg/dL)

365.1 (2.94)

359.9 (355.3, 364.6)

359

80

277.1, 481.2

 Transferrin saturation (%)

21.8 (0.51)

19.1 (18.4, 19.9)

19.9

14.1

7.00, 39.2

Environmental exposure

 Blood lead (μg/dL)

1.34 (0.04)

1.09 (1.04, 1.15)

1.06

0.88

0.46, 2.96

0.3, 0.25

0.4

 Blood cadmium (μg/L)

0.27 (0.006)

0.23 (0.22, 0.23)

0.21

0.18

0.10, 0.59

0.14, 0.2

34.7

 Blood mercury, total (μg/L)

1.73 (0.09)

1.08 (0.97, 1.19)

1.02

1.48

0.21, 5.58

0.2, 0.33

7.6

 Blood benzene (ng/mL)

0.030 (0.002)

0.024 (0.22, 0.026)

0.017

0.014

0.017, 0.060

0.024

57.2

 Blood toluene (ng/mL)

0.162 (0.034)

0.087 (0.078, 0.097)

0.084

0.075

0.024, 0.308

0.025

4.4

 Serum cotinine (ng/ml)

0.27 (0.04)

0.053 (0.046, 0.062)

0.04

0.1

0.01, 1.24

0.015

21.7