Table 2.
Distribution of lead, mercury, arsenic, cadmium, manganese, and aluminum concentrations in umbilical cord blood in a sample of n = 100 newborns from Jamaica.
| Variables | N | Mean (SD) | Median | Interquartile Range | Percentiles | ||||
|---|---|---|---|---|---|---|---|---|---|
| Arithmetic | Geometric | 25th | 75th | 90th | 95th | ||||
| Lead (µg/dL) | 100 | 0.8 (1.3) | 0.6 a (1.8) b | 0.6 | 0.3 | 0.4 | 0.8 | 1.2 | 1.7 |
| Mercury (µg/L) | 100 | 4.4 (2.4) | 3.9 a (1.6) b | 4.0 | 2.4 | 2.8 | 5.2 | 7.0 | 7.6 |
| Aluminum (µg/L) | 100 | 10.9 (9.2) | 7.7 a (2.4) b | 8.6 | 13.0 | 2.5 | 15.5 | 22.5 | 27.5 |
| Manganese (µg/L) | 100 | 43.7 (17.7) | NR e | 41.0 | 21.0 | 41.0 | 52.0 | 66.5 | 80.0 |
| Arsenic (µg/L) c | 100 | 1.0 (0.9) | NR e | 0.6 | 0.0 | 0.7 | 0.7 | 2.1 | 2.8 |
| Cadmium (µg/L) d | 100 | 0.07 (0.01) | NR e | 0.07 | 0.00 | 0.07 | 0.07 | 0.07 | 0.07 |
a Mean lead, mercury, and aluminum indicates the geometric mean = Exp. [Mean (ln of metal concentration)]; b SD of lead, mercury, and aluminum indicates the geometric standard deviation = Exp. [standard deviation of (ln of metal concentration)]; c 78 (78%) samples were below the limit of detection for arsenic; d 99 (99%) samples were below the limit of detection for cadmium. Also, for ease of understanding, the descriptive statistics for this variable are provided with two decimal places; e NR = geometric mean and standard deviation were not reported because ln-transformation was not applied to these variables.