assessed (prolactin, FSH, LH, and testosterone). Only 44 of the 50 samples were considered in the semen analysis because six veterans were azoospermic. Enzyme treatment was used for 17 samples (12 with low and 5 with high urinary uranium). In the assessment of genotoxicity, cultured peripheral blood lymphocytes were tested for chromosomal abnormalities and sister-chromatid exchange for baseline measurements. The cells were subjected to two concentrations of bleomycin (4 and 8 μg/mL). A number of potential confounders were adjusted for in the regression analysis, including current smoking status and use of psychotropic and antidepressant drugs. Robust regression analysis was used to account for highly influential observations of neurocognitive function in adjusting for intelligence (WRAT-3) and depression (BDI).
Urinary uranium ranged from 0.018 to 39.1 μg/g of creatinine in the depleted-uranium–exposed veterans with retained fragments and from 0.002 to 0.231 μg/g of creatinine in depleted-uranium–exposed veterans without fragments. In general, clinical tests revealed hematologic, renal, and neuroendocrine measures that were within normal limits with slight differences between high– and low–urinary-uranium groups. When veterans were assessed for active medical problems, those in the high-uranium group were found to suffer a higher proportion of injuries than those in the low-uranium group (76.9% vs 45.9%; p = 0.05). Hematologic measures had statistically significant differences between exposure groups that were not observed in the previous surveillance. The high–urinary-uranium group had a lower mean lymphocyte count (32% vs 37%; p = 0.04), a higher mean neutrophil percentage (55% vs 49%; p = 0.03), and a lower mean monocyte percentage (7.6% vs 9.1%; p = 0.01). The authors did not detect any clinically important changes in renal function due to depleted-uranium exposure. Urinary creatinine concentration was slightly lower in the high–urinary-uranium group, but the difference only marginally significant.
Results of neurocognitive tests were not consistent with those in past evaluations. The relationship between urinary uranium and performance on automated measures observed in the 1994 and 1997 surveillance appeared to weaken and was only marginally significant when WRAT-3 and the BDI were adjusted for high and low urinary uranium.
There were no statistically significant differences in concentrations of FSH, LH, prolactin, testosterone, TSH, or thyroid hormones between low and high groups. Of the 44 sperm samples included in the analysis, three were designated subnormal—that is, as having values of at least three of the five clinical measures below normal, as defined by the WHO standards. The high–urinary-uranium groups showed increases in mean total sperm count (583.5 ± 106.1 vs 286.6 ± 44.8), total progressive sperm (220.9 ± 44.0 vs 108.2 ± 19.2), and total rapid progressive sperm (155.5 ± 31.1 vs 81.3 ± 15.4), and the differences were significant (p < 0.02, 0.03, and 0.04, respectively).