Table 3.
Distribution of continuous variables of interest in the study population (20–50 year old nonsmokers)
| Arithmetic mean (SE) | Geometric mean (95 % CI) | Median | IQR | 5th, 95th percentile | LOD | % below LOD | |
|---|---|---|---|---|---|---|---|
| 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 |
Abbreviations: IQR interquartile range, LOD limit of detection, BMI body mass index, PIR ratio of family income to poverty, CRP C-reactive protein, MCHC mean corpuscular hemoglobin, TIBC total iron binding capacity
aThe detection limit for HDL is not found in the NHANES laboratory method for HDL