Urine uranium concentrations and renal function in residents of the United States--2001 to 2010.

CONTEXT: Animal model studies have demonstrated that subchronic oral uranium exposure is associated with renal dysfunction. Little is known about the effects of environmental exposure to uranium in humans. OBJECTIVE: To determine whether environmental exposure to uranium is associated with alterations in renal function among residents of the United States. METHODS: We analyzed data from the National Health and Nutrition Examination Survey (NHANES) 2001-2010. Inclusion criteria included the measurement of urine uranium concentration, serum creatinine (sCr), and urine albumin-creatinine ratio. Exclusion criteria included a reported history of diabetes mellitus. Urine uranium concentrations were normalized to urinary creatinine. Respondents with and without detectable urine uranium concentrations were compared using Welch's t-test for urine albumin-creatinine ratio and sCr and using Fisher's exact test for a reported history of renal disease. Regression analysis was performed to assess for an association between urine uranium concentration and urine albumin-creatinine ratio, sCr, or a reported history of renal disease. RESULTS: Uranium was detectable in the urine of 74.1% (n = 9025) of respondents. Urine albumin-creatinine ratio was significantly greater in respondents with detectable urine uranium concentrations (mean 4.84 ± 45.8 mg/g) compared to respondents without detectable urine uranium concentrations (mean 0.77 ± 3.7 mg/g) (p < 0.001). There was no significant difference between the groups with respect to sCr or a reported history of renal disease. Regression analysis did not show a statistically significant association between urine uranium concentration and urine albumin-creatinine ratio (p = 0.45), sCr (p = 0.71), or a reported history of renal disease (p = 0.05). CONCLUSIONS: In this study, a high proportion of the U.S. population had exposure to uranium. We demonstrated an association between detectable urine uranium concentrations and microalbuminuria in residents of the United States but no association with clinical renal disease.

Effect of single-dose Ginkgo biloba and Panax ginseng on driving performance.

CONTEXT: Panax ginseng and Gingko biloba are commonly used herbal supplements in the United States that have been reported to increase alertness and cognitive function. OBJECTIVE: The objective of this study was to investigate the effects of these specific herbals on driving performance. MATERIALS AND METHODS: 30 volunteers were tested using the STISIM3® Driving Simulator (Systems Technology Inc., Hawthorne, CA, USA) in this double-blind, placebo-controlled study. The subjects were randomized into 3 groups of 10 subjects per group. After 10-min of simulated driving, subjects received either ginseng (1200 mg), Gingko (240 mg), or placebo administered orally. The test herbals and placebo were randomized and administered by a research assistant outside of the study to maintain blinding. One hour following administration of the herbals or placebo, the subjects completed an additional 10-min of simulated driving. Standard driving parameters were studied including reaction time, standard deviation of lateral positioning, and divided attention. Data collected for the divided attention parameter included time to response and number of correct responses. The data was analyzed with repeated-measures analysis of variance (ANOVA) and Kruskal-Wallis test using SPSS 22 (IBM, Armonk, NY, USA). RESULTS: There was no difference in reaction time or standard deviation of lateral positioning for both the ginseng and Ginkgo arms. For the divided attention parameter, the response time in the Ginkgo arm decreased from 2.9 to 2.5 s. The ginseng arm also decreased from 3.2 to 2.4 s. None of these values were statistically significant when between group differences were analyzed. DISCUSSION AND CONCLUSION: The data suggests there was no statistically significant difference between ginseng, Ginkgo or placebo on driving performance. We postulate this is due to the relatively small numbers in our study. Further study with a larger sample size may be needed in order to elucidate more fully the effects of Ginkgo and ginseng on driving ability.