In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Q: Context: Cannabis use disorders (CUD) may influence the course of bipolar disorder (BD), but key confounding factors such as tobacco smoking have not been adequately addressed. This study examined whether CUD was associated with a more severe illness course in tobacco smoking BD patients.', 'A sample of French and Norwegian tobacco smoking patients with BD I and II (N=642) was investigated. DSM-IV diagnoses and other characteristics were obtained through personal interviews using structured questionnaires. The association between CUD and illness course was assessed in regression analyses.', 'In bivariate analyses, CUD was associated with earlier BD onset, higher frequency of manic (in BD I) and depressive episodes and hospitalizations per illness year, and a higher occurrence of psychotic episodes. After controlling for potential confounders, the relationships with earlier BD onset (B=-5.60 95% CI=-7.65 to -3.64), and increased rates of manic episodes (OR=1.93, 95% CI: 1.15 to 3.23) and hospitalizations (OR=2.93, 95% CI: 1.85 to 4.64) remained statistically significant.\Question: Is cannabis use disorder associated with greater illness severity in tobacco smoking patients with bipolar disorder?

A: Despite the multivariate approach, differences between the two samples may lead to spurious findings related to hidden confounders. Substance use and mood episode information was collected retrospectively, and potential birth cohort effects could not be controlled for.
****
Q: Context: This study was conducted to determine if there was an increase in the urinary excretion of fluoride, after the use of fluoride mouth rinses in children.', 'The sample consisted of 58 children aged 5-8 years, randomly selected, residents in non-fluoridated water areas. Urine samples were collected prior to mouthwash and also 2 hours after use. The control sample, which received no treatment, consisted of 16 children of equivalent age and from the same community. Urinary excretion of fluoride was analysed by determining the pH, creatinine, F- ion and fluoride (mg)/creatinine (g) (F/Cr) ratio in urine. Results In the studied sample, the mean F/Cr ratio before fluoride mouth rinse was 0.26 mg/g and it rose to 1.58 mg/g 2 hours after mouth rinse. This difference of 1.33 mg/g was statistically highly significant (p<.001). In the control group no significant changes occurred. The average 2 hours afterward F/Cr ratios were 0.29 and 0.27 respectively (p=0.426).\Question: Does renal excretion of fluoride after fluoride mouth rinse in children?

A: After the use of a fluoride mouthwash, in children, there is a statistically significant increase of fluoride ion in urine, which can be attributed to the application of this product.
****
Q: Context: An electro-spray ionisation ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) application for the quantitative analysis of amino acids was developed. The suitability for the detection and follow-up of patients suffering from inborn errors of metabolism (IEM) was assessed by extensive cross-validation with ion-exchange liquid chromatography (IEX-LC) with post-column ninhydrin derivatisation, participation in external quality control (ERNDIM) and analysis of samples of patients with confirmed IEM.', 'Prior to analysis plasma and urine samples were merely diluted 150-fold in mobile phase. Amino acids were detected in the multiple reaction monitoring mode (MRM) in the ESI-positive mode. The analytical results were compared with IEX-LC. External quality control scheme performance is presented.', 'Comprehensive analysis of amino acids in plasma and urine was achieved with a run-to-run time of 30min. Validation results were satisfactory and there was a very good correlation between UPLC-MS/MS and IEX-LC. Analytical results obtained in the external quality control scheme were essentially the same as those of the other participants. Patients suffering from IEM were readily identified.\Question: Is quantitative UPLC-MS/MS analysis of underivatised amino acids in body fluids a reliable tool for the diagnosis and follow-up of patients with inborn errors of metabolism?

A:
UPLC-MS/MS analysis of amino acids in body fluids is rapid, reliable and suitable for the diagnosis and follow-up patients with IEM.
****