Table 4.
Urinary tin concentration (unadjusted and creatinine adjusted) in U.S. children in NHANES 2011–2014.
| Variable | Number | Detection rate, % |
Urinary tin concentration, µg/L
|
Urinary tin concentration, µg/g creatinine
|
||||
|---|---|---|---|---|---|---|---|---|
| Median (P25-P75) |
Geometric means (SE) |
p | Median (P25-P75) |
Geometric means (SE) |
P | |||
| Total | 1641 | 91.29 | 0.60 (0.27–1.58) | 0.66 (0.04) | 0.72 (0.32–1.63) | 0.74 (0.04) | ||
| Age | ||||||||
| 6–11 | 800 | 95.25 | 0.94 (0.43–2.48) | 1.01 (0.07) | <0.0001 | 1.49 (0.76–2.82) | 1.47 (0.08) | <0.0001 |
| 12–19 | 841 | 87.51 | 0.43 (0.22–1.01) | 0.49 (0.03) | 0.41 (0.22–0.85) | 0.45 (0.03) | ||
| Gender | ||||||||
| Male | 835 | 91.26 | 0.59 (0.26–1.45) | 0.64 (0.05) | 0.60 | 0.66 (0.30–1.49) | 0.70 (0.05) | 0.26 |
| Female | 806 | 91.32 | 0.63 (0.28–1.62) | 0.68 (0.05) | 0.78 (0.34–1.72) | 0.78 (0.06) | ||
| Race/ethnicitya | ||||||||
| Non-Hispanic white | 398 | 86.93 | 0.48 (0.24–1.24) | 0.55 (0.05) | 0.67 (0.30–1.41) | 0.67 (0.07) | ||
| Hispanic | 525 | 92.95 | 0.65 (0.32–1.63) | 0.72 (0.05) | 0.001 | 0.73 (0.32–1.80) | 0.81 (0.05) | 0.08 |
| Non-Hispanic black | 445 | 95.73 | 1.16 (0.46–2.68) | V1.13 (0.11) | 0.94 (0.35–2.16) | 0.90 (0.08) | ||
| Other | 273 | 87.18 | 0.55 (0.23–0.33) | 0.61 (0.10) | 0.68 (0.33–1.82) | 0.76 (0.10) | ||
| Family income to poverty ratiob | ||||||||
| ≤1.30 | 723 | 93.78 | 0.85 (0.34–1.99) | 0.88 (0.07) | 0.83 (0.38–2.06) | 0.92 (0.06) | ||
| 1.30–3.50 | 505 | 89.70 | 0.56 (0.25–1.61) | 0.65 (0.05) | 0.02 | 0.73 (0.28–1.52) | 0.71 (0.05) | 0.03 |
| >3.50 | 291 | 86.94 | 0.47 (0.22–0.94) | 0.50 (0.05) | 0.51 (0.31–1.32) | 0.60 (0.08) | ||
| Missing | 122 | 93.44 | 0.48 (0.27–1.05) | 0.51 (0.08) | 0.60 (0.35–1.45) | 0.70 (0.09) | ||
| BMI categoryc | ||||||||
| Normal weight | 1023 | 91.01 | 0.57 (0.27–1.60) | 0.65 (0.04) | 0.72 (0.32–1.73) | 0.76 (0.05) | ||
| Overweight | 259 | 89.58 | 0.63 (0.30–1.40) | 0.66 (0.06) | 0.67 | 0. 0.33–1.43) | 0.73 (0.06) | 0.27 |
| Obese | 340 | 93.24 | 0.63 (0.25–1.84) | 0.69 (0.07) | 0.60 (0.30–1.58) | 0.68 (0.07) | ||
| Missing | 19 | 94.74 | 0.80 (0.35–1.28) | 0.89 (0.26) | 0.87 (0.57–1.35) | 0.97 (0.26) | ||
All the variables were adjusted using population weights for the sample in which tin concentration was measured except N (unweighted sample size). Analysis of variance (ANOVA) was used to compare differences of urinary concentrations of tin among various categorical variables. The lower limit of detection of the urinary tin analysis was 0.090 µg/L.
Race/ethnicity was categorized based on self-reported data into Hispanic (including Mexican and non-Mexican Hispanic), non-Hispanic white, non-Hispanic black and other race/ethnicity (Liu et al., 2017).
Family income to poverty ratios were categorized as ≤ 1.30, 1.30–3.50, and > 3.50 (Johnson et al., 2013; Liu et al., 2017).
BMI was calculated as weight in kilograms divided by the square of height in meters and classified as normal weight, overweight, and obese based on the CDC’s sex-specific 2000 BMI-for-age growth charts for the U.S. Weight and height were determined by trained health technicians according to the NHANES Anthropometry Procedures Manual (WHO, n.d.-b).
CDC, Center for Disease Control and Prevention; BMI, body mass index; SE, standard error.