Dataset Information

Differentiating new cannabis use from residual urinary cannabinoid excretion in chronic, daily cannabis users.

ABSTRACT:

Aims

To develop and validate empirically a mathematical model for identifying new cannabis use in chronic, daily cannabis smokers.

Design

Models were based on urinary creatinine-normalized (CN) cannabinoid excretion in chronic cannabis smokers.

Setting

For model development, participants resided on a secure research unit for 30 days. For model validation, participants were abstinent with daily observed urine specimens for 28 days.

Participants

A total of 48 (model development) and 67 (model validation) daily cannabis smokers were recruited.

Measurements

All voided urine was collected and analyzed for 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) by gas chromatography-mass spectrometry (GCMS; limit of quantification 2.5 ng/ml) and creatinine (mg/ml). Urine THCCOOH was normalized to creatinine, yielding ng/mg CN-THCCOOH concentrations. Urine concentration ratios were determined from 123,513 specimen pairs collected 2-30 days apart.

Findings

A mono-exponential model (with two parameters, initial urine specimen CN-THCCOOH concentration and time between specimens), based on the Marquardt-Levenberg algorithm, provided a reasonable data fit. Prediction intervals with varying probability levels (80, 90, 95, 99%) provide upper ratio limits for each urine specimen pair. Ratios above these limits suggest cannabis re-use. Disproportionate numbers of ratios were higher than expected for some participants, prompting development of two additional rules that avoid misidentification of re-use in participants with unusual CN-THCCOOH excretion patterns.

Conclusions

For the first time, a validated model is available to aid in the differentiation of new cannabis use from residual creatinine-normalized 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (CN-THCCOOH) excretion in chronic, daily cannabis users. These models are valuable for clinicians, toxicologists and drug treatment staff and work-place, military and criminal justice drug-testing programs.

SUBMITTER: Schwilke EW

PROVIDER: S-EPMC3461262 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Differentiating new cannabis use from residual urinary cannabinoid excretion in chronic, daily cannabis users.

Schwilke Eugene W EW Gullberg Rod G RG Darwin William D WD Chiang C Nora CN Cadet Jean Lud JL Gorelick David A DA Pope Harrison G HG Huestis Marilyn A MA

Addiction (Abingdon, England) 20101206 3

<h4>Aims</h4>To develop and validate empirically a mathematical model for identifying new cannabis use in chronic, daily cannabis smokers.<h4>Design</h4>Models were based on urinary creatinine-normalized (CN) cannabinoid excretion in chronic cannabis smokers.<h4>Setting</h4>For model development, participants resided on a secure research unit for 30 days. For model validation, participants were abstinent with daily observed urine specimens for 28 days.<h4>Participants</h4>A total of 48 (model de ...[more]

PMID: 21134021

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Project description:Traditionally, smoking has been the predominant method for administering cannabis, but alternative routes of administration have become more prevalent. Additionally, research examining urinary cannabinoid excretion profiles has primarily focused on 11-nor-9-carboxy-∆9-tetrahydrocannabinol (∆9-THC-COOH), a metabolite of ∆9-tetrahydrocannabinol (∆9-THC), as the primary analyte. The aim of the current study was to characterize the urinary excretion profile of ∆9-THC-COOH, ∆9-THC, ∆8-tetrahydrocannabinol (∆8-THC), 11-hydroxy-∆9-tetrahydrocannabinol (11-OH-∆9-THC), ∆9-tetrahydrocannabivarin (THCV), 11-nor-∆9-tetrahydrocannabivarin-9-carboxlic acid (THCV-COOH), cannabidiol (CBD), cannabinol (CBN) and 8,11-dihydroxytetrahydrocannabinol (8,11-diOH-∆9-THC) following controlled administration of both oral and vaporized cannabis. Participants (n = 21, 11 men/10 women) who were infrequent cannabis users ingested cannabis-containing brownies (0, 10 and 25 mg ∆9-THC) and inhaled vaporized cannabis (0, 5 and 20 mg ∆9-THC) across six double-blind outpatient sessions. Urinary concentrations of ∆9-THC analytes were measured at baseline and for 8 h after cannabis administration. Sensitivity, specificity and agreement between the three immunoassays (IAs) for ∆9-THC-COOH (cutoffs of 20, 50 and 100 ng/mL) and liquid chromatography-tandem mass spectrometry (LC-MS-MS) analyses (confirmatory cutoff concentrations of 15 ng/mL) were assessed. Urinary concentrations for ∆9-THC-COOH, ∆9-THC, 11-OH-∆9-THC, THCV, CBN and 8,11-diOH-∆9-THC all peaked at 5-6 h and 4 h following oral and vaporized cannabis administration, respectively. At each active dose, median maximum concentrations (Cmax) for detected analytes were quantitatively higher after oral cannabis administration compared to vaporized. Using current recommended federal workplace drug-testing criteria (screening via IA with a cutoff of ≥50 ng/mL and confirmation via LC-MS-MS at a cutoff of ≥15 ng/mL), urine specimens tested positive for ∆9-THC-COOH in 97.6% of oral sessions and 59.5% of vaporized sessions with active ∆9-THC doses. These data indicate that while ∆9-THC-COOH may serve as the most consistent confirmatory analyte under the current drug-testing guidelines, future work examining 11-OH-∆9-THC under similar parameters could yield an alternative analyte that may be helpful in distinguishing between licit and illicit cannabis products.

Project description:ObjectiveDaily cannabis users develop tolerance to some drug effects, but the extent to which this diminishes driving impairment is uncertain. This study compared the impact of acute cannabis use on driving performance in occasional and daily cannabis users using a driving simulator.MethodsWe used a within-subjects design to observe driving performance in adults age 25 to 45 years with different cannabis use histories. Eighty-five participants (43 males, 42 females) were included in the final analysis: 24 occasional users (1 to 2 times per week), 31 daily users and 30 non-users. A car-based driving simulator (MiniSim™, National Advanced Driving Simulator) was used to obtain two measures of driving performance, standard deviation of lateral placement (SDLP) and speed relative to posted speed limit, in simulated urban driving scenarios at baseline and 30 min after a 15 min ad libitum cannabis smoking period. Participants smoked self-supplied cannabis flower product (15% to 30% tetrahydrocannabinol (THC). Blood samples were collected before and after smoking (30 min after the start of smoking). Non-users performed the same driving scenarios before and after an equivalent rest interval. Changes in driving performance were analyzed by repeated measures general linear models.ResultsMean whole blood THC cannabinoids concentrations post smoking were use THC = 6.4 ± 5.6 ng/ml, THC-COOH = 10.9 ± 8.79 ng/mL for occasional users and THC = 36.4 ± 37.4 ng/mL, THC-COOH = 98.1 ± 90.6 ng/mL for daily users. On a scale of 0 to 100, the mean post-use score of subjective high was similar in occasional users and daily users (52.4 and 47.2, respectively). In covariate-adjusted analysis, occasional users had a significant increase in SDLP in the straight road segment from pre to post compared to non-users; non-users decreased by a mean of 1.1 cm (25.5 cm to 24.4 cm) while occasional users increased by a mean of 1.9 cm (21.7 cm to 23.6 cm; p = 0.02). Daily users also increased adjusted SDLP in straight road segments from baseline to post-use (23.2 cm to 25.0 cm), but the change relative to non-users was not statistically significant (p = 0.08). The standardized mean difference in unadjusted SDLP from baseline to post-use in the straight road segments comparing occasional users to non-users was 0.64 (95% CI 0.09 - 1.19), a statistically significant moderate increase. When occasional users were contrasted with daily users, the baseline to post changes in SDLP were not statistically significant. Daily users exhibited a mean decrease in baseline to post-use adjusted speed in straight road segments of 1.16 mph; a significant change compared to slight speed increases in the non-users and occasional users (p = 0.02 and p = 0.01, respectively).ConclusionWe observed a decrement in driving performance assessed by SDLP after acute cannabis smoking that was statistically significant only in the occasional users in comparison to the nonusers. Direct contrasts between the occasional users and daily users in SDLP were not statistically significant. Daily users drove slower after cannabis use as compared to the occasional use group and non-users. The study results do not conclusively establish that occasional users exhibit more driving impairment than daily users when both smoke cannabis ad libitum.

Project description:BackgroundSalt usage patterns have been associated with a risk of multiple diseases; however, their relationship with heavy metal exposure has not been extensively studied.MethodsThis study analyzed survey data from 11,574 NHANES participants. Weighted linear regression models were used to examine the relationship between the type of salt used by participants, the frequency of adding salt at the table, and the frequency of adding regular or seasoned salt to cooking or food preparation, and urinary concentrations of 10 heavy metals. Multiple sensitivity analyses were also performed.ResultsThe weighted regression analysis indicated that participants' salt usage patterns were associated with an increased urinary excretion of certain heavy metals. Specifically, regarding the type of salt used, compared to regular salt, the use of salt substitutes was significantly positively correlated with urinary molybdenum (Mo) levels, while not using salt or substitutes at the table was significantly positively correlated with urinary levels of both Mo and arsenic (As). In terms of the frequency of adding regular salt at the table, frequent addition compared to rarely adding salt was significantly positively correlated with urinary levels of cadmium (Cd), and antimony (Sb), while showing a significant negative correlation with urinary Mo levels. Additionally, when examining the frequency of using regular salt during cooking or food preparation, those who occasionally or very often added regular salt had significantly higher urinary levels of barium (Ba), cesium (Cs), and thallium (Tl) compared to those who never added regular salt during cooking. These associations remained stable in sensitivity analyses.ConclusionOur analysis revealed that participants' salt usage patterns are associated with increased excretion of certain heavy metals, suggesting possible increased exposures to these metals. While these findings are concerning, they require validation in other populations and should be confirmed through prospective studies designed based on this hypothesis.

Dataset Information

Differentiating new cannabis use from residual urinary cannabinoid excretion in chronic, daily cannabis users.

Aims

Design

Setting

Participants

Measurements

Findings

Conclusions

Publications

Differentiating new cannabis use from residual urinary cannabinoid excretion in chronic, daily cannabis users.

Similar Datasets

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