Urine Cotinine Screening Detects Nearly Ubiquitous Tobacco Smoke Exposure in Urban Adolescents

Environmental tobacco smoke exposure in a multi-city cohort of children with asthma: Analyzing true exposure and the validity of caregiver survey

Introduction

The avoidance of asthma triggers, like tobacco smoke, facilitates asthma management. Reliance upon caregiver report of their child's environmental tobacco smoke (ETS) exposure may result in information bias and impaired asthma management. This analysis aimed to characterize the chronicity of ETS exposure, assess the validity of caregiver report of ETS exposure, and investigate the relationship between ETS exposure and asthma attack.

Methods

A secondary data analysis was performed on data from a longitudinal study of 162 children aged 7-12 years with asthma living in federally subsidized housing in three US cities (Boston, Cincinnati, and New Orleans). Data were collected at three time points over 1 year.

Results

Over 90% of children were exposed to ETS (≥0.25 ng/ml of urine cotinine (UC)). Exposure was consistent over 1 year. Questionnaire data had a sensitivity of 28-34% using UC ≥0.25 ng/ml as the gold standard. High ETS exposure (UC ≥ 30 ng/ml) was significantly associated with asthma attack (aOR 2.97, 0.93-9.52, p = 0.07). Lower levels (UC 0.25-30 ng/ml) were not statistically significant (aOR 1.76, 0.71- 4.38, p = 0.22). No association was found using caregiver-reported ETS exposure.

Conclusion

Relying on questionnaire data to assess children's exposure to tobacco smoke may lead to substantial information bias. For children with asthma, incorrect characterization may substantially impact asthma morbidity.

Passive Smoking Exposure Modifies Cardiovascular Structure and Function: Beijing Child Growth and Health Cohort (PROC) Study

Passive smoking exposure in children is prevalent worldwide and exposes children to respiratory and systemic toxins. In this study, we enrolled 568 children to study how secondhand smoke (SHS) might affect children's cardiovascular health in China. The measurement of nicotine and its metabolites in urine showed that 78.9% of children were exposed to SHS. Children exposed to SHS had greater interventricular septum thickness (p = 0.005) and left ventricular mass index (p = 0.008) than nonexposed children. Urinary norcotinine levels were associated with increased ascending aorta diameter (β = 0.10, 95%CI 0.02-0.17) and decreased left ventricular end systolic diameter (β = -0.10, 95%CI -0.19 to -0.01). The effects of SHS exposure on cardiovascular function: norcotinine levels associated with lower left ventricular mass index (β = -0.32, 95%CI -0.59 to -0.05), left ventricular end diastolic volume index (β = -0.43, 95%CI -0.85 to -0.02), and left ventricular end systolic volume index (β = -0.20, 95%CI -0.37 to -0.03). Moreover, there no no significant associations of nicotine, cotinine, and trans-3'-hydroxycotinine with cardiovascular health. Overall, SHS exposure in children remains prevalent in Beijing and may affect children's cardiovascular development, in both structure and function. It suggests that stricter and practical measures are needed toward the elimination of tobacco use in children's environments.

Secondhand smoke exposure in school children in Malta assessed through urinary biomarkers

School children may be exposed to secondhand smoke (SHS) either at home, in transit or in social gatherings permitting smoking in their presence. Questionnaires about SHS often underestimate prevalence and extent of exposure. A more accurate tool is the use of biomarkers such as cotinine (COT) and trans-3'-hydrocycotinine (3HC) as biomarkers of SHS exposure, alongside 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a reduction product in the body of the tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), both potent carcinogens. We measured urinary COT, 3HC and total NNAL using sensitive and specific high-performance LC-MS/MS methods. The limit of quantification (LOQ) for each assay were 0.05 ng/mL, 0.1 ng/mL and 0.25 pg/mL respectively. The aim of this study was to evaluate the exposure to SHS of school children (9-11 years), from five public schools in the island of Malta, from questionnaire information about smoking at home and verify it by urinary biomarker data of COT, 3HC and NNAL. These biomarkers were measurable in 99.4%, 95.4% and 98.3% of the participating children respectively. From the children reporting smoking at home, 11% had a history of asthma and had COT, 3HC and NNAL geometric mean concentrations double compared to the non-asthmatic group. In has been confirmed that non-smokers exposed to SHS and THS have a higher NNAL/COT ratio than the group identified as smokers according to specific and defined COT threshold levels (despite the fact that a priori, the entire study group was composed of non-smokers). The implication of high measured levels of urinary NNAL in children should be of concern given its potency. A main effects multifactor ANOVA model was developed and the children's house and school locations and the smoking frequency were statistically significant to predict the levels of the three metabolites. For 3HC only, the status of the employment of the mother was also an important predictor.

Updated fraction of cancer attributable to lifestyle and environmental factors in Denmark in 2018

Environmental exposures and avoidable risk factors account for a large proportion of cancer burden. Exposures and lifestyle vary over time and between populations, which calls for updated and population-specific quantification of how various avoidable risk factors influence cancer risk to plan and design rational and targeted prevention initiatives. The study considered 12 risk-factor groups categorized as class I carcinogens by IARC/WCRF. Exposure data was derived from national studies and surveys and were linked to cancer incidence in 2018 based on the nationwide Danish Cancer Registry. In 2018, 23,078 men and 21,196 women were diagnosed with cancer excluding non-melanoma skin cancer, in Denmark. Of these, 14,235 (32.2%) were estimated to be attributable to avoidable class I carcinogens. Tobacco smoking accounted for 14.6% of total cancers, followed by UV-radiation that accounted for 5.8%. Based on exposure data from 2008, one-third of the cancers in Denmark in 2018 are estimated to be caused by class I carcinogens with tobacco use being the main contributor followed by UV-radiation. Our results should be integrated with public health policies to effectively increase awareness and promote strategies to decrease risk factor exposures at population level.

Assessing secondhand and thirdhand tobacco smoke exposure in Canadian infants using questionnaires, biomarkers, and machine learning

BACKGROUND

As smoking prevalence has decreased in Canada, particularly during pregnancy and around children, and technological improvements have lowered detection limits, the use of traditional tobacco smoke biomarkers in infant populations requires re-evaluation.

OBJECTIVE

We evaluated concentrations of urinary nicotine biomarkers, cotinine and trans-3'-hydroxycotinine (3HC), and questionnaire responses. We used machine learning and prediction modeling to understand sources of tobacco smoke exposure for infants from the CHILD Cohort Study.

METHODS

Multivariable linear regression models, chosen through a combination of conceptual and data-driven strategies including random forest regression, assessed the ability of questionnaires to predict variation in urinary cotinine and 3HC concentrations of 2017 3-month-old infants.

RESULTS

Although only 2% of mothers reported smoking prior to and throughout their pregnancy, cotinine and 3HC were detected in 76 and 89% of the infants' urine (n = 2017). Questionnaire-based models explained 31 and 41% of the variance in cotinine and 3HC levels, respectively. Observed concentrations suggest 0.25 and 0.50 ng/mL as cut-points in cotinine and 3HC to characterize SHS exposure. This cut-point suggests that 23.5% of infants had moderate or regular smoke exposure.

SIGNIFICANCE

Though most people make efforts to reduce exposure to their infants, parents do not appear to consider the pervasiveness and persistence of secondhand and thirdhand smoke. More than half of the variation in urinary cotinine and 3HC in infants could not be predicted with modeling. The pervasiveness of thirdhand smoke, the potential for dermal and oral routes of nicotine exposure, along with changes in public perceptions of smoking exposure and risk warrant further exploration.

Prevalence and Quantification of Secondhand Smoke Exposure Among Hospitalized Children <6 Years of Age

OBJECTIVES

Using caregiver report and urinary cotinine measures, we defined the prevalence of secondhand smoke (SHS) exposure among young, hospitalized children and compared exposure among those hospitalized with pneumonia versus those with acute, nonrespiratory illnesses.

METHODS

Children aged <6 years hospitalized with pneumonia or acute, nonrespiratory illnesses were enrolled on admission, and urinary cotinine, a nicotine biomarker, was measured. Caregivers were also queried on home SHS exposure. We modeled associations between sociodemographic characteristics and exposure intensity on the basis of cotinine level (none, light, and heavy) using multivariable proportional odds regression. We also examined associations between SHS exposure intensity and diagnosis (pneumonia versus nonrespiratory illness). For this analysis, diagnosis was the outcome of interest, and urinary cotinine was the primary exposure variable.

RESULTS

Overall, 36% of the 239 enrolled children had reported home SHS exposure, although 77% had detectable levels of urinary cotinine, including 59% with heavy exposure. The highest urinary cotinine level was among children exposed to indoor smoking (7.78 ng/mL, interquartile range 2.93-18.65; P < .001). Increased SHS exposure was associated with non-Hispanic ethnicity, lower household educational attainment, and public insurance. There were no differences in SHS exposure by diagnosis.

CONCLUSIONS

Among hospitalized young children, reported home SHS exposure was common but substantially underestimated when compared with urinary cotinine levels. The highest urinary cotinine levels were among children exposed to indoor smoking. Future public health interventions, as well as more robust SHS exposure screenings on hospital admission, are needed to reduce the prevalence of SHS exposure among young children.

Factors Associated With the Differences Between Self-Report Smoking and Urinary Cotinine Criteria

During self-reporting, respondents underreport their smoking status for various reasons. We aimed to evaluate the difference between smoking status self-reporting and urinary cotinine tests in Korea respondents. Logistic regression analyses were performed to identify factors associated with the differences between self-reporting and urinary cotinine criteria. The dependent variable was the underreporting of smoking status; independent variables were sociodemographic, health status, and secondhand smoke (SHS) exposure. Total underreporting was 3.6% when Cot ≥164 and 4.0% when Cot-variable (classified) criteria underreported. Positive associations were found between smoking and age, education, drinking, and SHS. Underreporting in the nonsmoker group (odds ratio [OR] = 2.336; confidence interval [CI] = 1.717-3.179) was significantly associated with SHS, but this difference was nonsignificant in the ex-smoker group (OR = 1.184; CI = 0.879-1.638). Underreporting was 3.6% to 4.0%, and C-statistics was about 0.7, indicating that outcomes could be classified. SHS in nonsmokers was positively associated with underreporting; however, only the nonsmoker group had positive associations, demonstrating unintentional underreporting due to SHS.

Biochemical Verification of Tobacco Use and Abstinence: 2019 Update

BACKGROUND

The changing prevalence and patterns of tobacco use, the advent of novel nicotine delivery devices, and the development of new biomarkers prompted an update of the 2002 Society for Research on Nicotine and Tobacco (SRNT) report on whether and how to apply biomarker verification for tobacco use and abstinence.

METHODS

The SRNT Treatment Research Network convened a group of investigators with expertise in tobacco biomarkers to update the recommendations of the 2002 SNRT Biochemical Verification Report.

RESULTS

Biochemical verification of tobacco use and abstinence increases scientific rigor and is recommended in clinical trials of smoking cessation, when feasible. Sources, appropriate biospecimens, cutpoints, time of detection windows and analytic methods for carbon monoxide, cotinine (including over the counter tests), total nicotine equivalents, minor tobacco alkaloids, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol are reviewed, as well as biochemical approaches to distinguishing cigarette smoking from use of electronic nicotine delivery devices (ENDS).

CONCLUSIONS

Recommendations are provided for whether and how to use biochemical verification of tobacco use and abstinence. Guidelines are provided on which biomarkers to use, which biospecimens to use, optimal cutpoints, time windows to detection, and methodology for biochemical verifications. Use of combinations of biomarkers is recommended for assessment of ENDS use.

IMPLICATIONS

Biochemical verification increases scientific rigor, but there are drawbacks that need to be assessed to determine whether the benefits of biochemical verification outweigh the costs, including the cost of the assays, the feasibility of sample collection, the ability to draw clear conclusions based on the duration of abstinence, and the variability of the assay within the study population. This paper provides updated recommendations from the 2002 SRNT report on whether and how to use biochemical markers in determining tobacco use and abstinence.

Health effects of concurrent ambient and tobacco smoke-derived particle exposures at low concentrations in children with asthma

Exposure to particulate matter less than 2.5 microns from either ambient pollution (AMB-PM_2.5) or secondhand smoke (SHS-PM_2.5) have been associated with asthma worsening, but there is little information on effects and relative potency with concurrent exposures. We studied health effects of concurrent exposures to AMB-PM_2.5 and SHS-PM_2.5 over a 6-year period in schoolchildren with asthma. Regression calibration with instrumental variables (RCIV) was utilized to estimate effects of personal exposure to low-level SHS and AMB-PM_2.5 on daily albuterol usage and urinary leukotriene E4 (uLTE₄; a biomarker of asthma-related inflammation) using urine cotinine and concentrations from fixed and personal pollution monitors. Each IQR increase in SHS-PM_2.5 exposure was associated with a 6.7% increase (95% CI: 1.0-12.8%) in uLTE₄ on the same day and 9.4% increase (95% CI: -2.6 to 22.7%) in albuterol use the next day, when children were co-exposed to mean levels of AMB-PM_2.5. The dose-response relationship between health outcomes and one pollutant was higher at lower levels of the other pollutant. For example, at lower levels of predicted SHS-PM_2.5 exposure, increases in health outcomes per IQR increase in AMB-PM_2.5 ranged between 2 and 5%, but were negligible at higher SHS-PM_2.5 levels. Comparing at equivalent co-exposure levels, SHS-PM_2.5 was 1.6 times more potent than AMB-PM_2.5 for uLTE₄ (95% CI: 1.1-2.3); estimates for albuterol usage were similar but less significant. Effects at mean co-exposure levels were closer [SHS to AMB-PM_2.5 potency ratio = 1.2 (95% CI: 0.9-1.5) for uLTE₄ and 1.2 (95% CI: 0.7-1.9) for albuterol usage]. In summary, concurrent exposure to relatively low levels of SHS and AMB-PM_2.5 were associated with health outcomes in asthmatic schoolchildren. Dose responses varied with changes in the relative amounts of each pollutant; SHS-PM_2.5 was observed to be more potent than AMB-PM_2.5 when co-exposure levels were equivalent.

Isotope dilution-LC-MS/MS method for quantification of the urinary cotinine-to-creatinine ratio

Background

Appropriate monitoring of tobacco smoking is extremely important in several areas of medicine, e.g. management of chronic obstructive pulmonary disease (COPD), epidemiological surveys, and allocation of heart or lung transplants. The major metabolite of nicotine is cotinine that is increasingly used as a laboratory parameter for assessing tobacco smoke exposure.

Methods

Creatinine and cotinine were analyzed simultaneously in urine by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in one run within 3 min using a biphenyl column. For quantification, the respective stable-isotope-labeled standards were used.

Results

Detuning and measuring a natural isotope of creatinine as precursor and product ion allowed a simultaneous quantification of creatinine and cotinine. The method revealed robust validation results. For both analytes, inaccuracy and imprecision of the quality control and external quality assessment (EQA) samples were ≤-11.1%.

Conclusions

One essential novelty of the method presented here is the simultaneous quantification of creatinine and cotinine covered by one analytical method. Despite the very different natural concentrations of creatinine and cotinine, this allows the immediate reporting of the cotinine-to-creatinine ratio without the need for a separate creatinine analysis.

A Mobile Health Intervention for Adolescents Exposed to Secondhand Smoke: Pilot Feasibility and Efficacy Study

Background

Secondhand smoke (SHS) exposure in children and adolescents has adverse health effects. For adolescents of lower socioeconomic status (SES), exposure is widespread, evidenced in the measurement of urinary cotinine, a major metabolite of nicotine. Direct intervention with exposed children has been proposed as a novel method, yet there is minimal evidence of its efficacy. Combining this approach with a mobile health (mHealth) intervention may be more time and cost-effective and feasible for adolescent populations.

Objective

In this pilot study, we assessed the feasibility and preliminary evidence of efficacy of a 30-day text message–based mHealth intervention targeted at reducing SHS exposure in adolescent populations of low SES.

Methods

For the study, 14 nonsmoking and nonvaping participants between the ages of 12-21 years exposed to SHS were enrolled. The intervention consisted of a daily text message sent to the participants over the course of a month. Text message types included facts and information about SHS, behavioral methods for SHS avoidance, or true-or-false questions. Participants were asked to respond to each message within 24 hours as confirmation of receipt. Feasibility outcomes included completion of the 30-day intervention, receiving and responding to text messages, and feedback on the messages. Efficacy outcomes included a reduction in urinary cotinine, accuracy of true-or-false responses, and participants’ perceptions of effectiveness.

Results

Of the 14 participants that were enrolled, 13 completed the intervention. Though not required, all participants had their own cell phones with unlimited text messaging plans. Of the total number of text messages sent to the 13 completers, 91% (372/407) of them received on-time responses. Participant feedback was generally positive, with most requesting more informational and true-or-false questions. In terms of efficacy, 54% (6/11) of participants reduced their cotinine levels (however, change for the group overall was not statistically significant (P=.33) and 45% (5/11) of participants increased their cotinine levels. Of the total number of true-or-false questions sent across all completers, 77% (56/73) were answered correctly. Participants’ ratings of message effectiveness averaged 85 on a scale of 100.

Conclusions

In this pilot study, the intervention was feasible as the majority of participants had access to a cell phone, completed the study, and engaged by responding to the messages. The efficacy of the study requires further replication, as only half of the participants reduced their cotinine levels. However, participants answered the majority of true-or-false questions accurately and reported that the messages were helpful.

How the Bidi Tobacco Industry Harms Child-workers: Results From a Walk-through and Quantitative Survey

Objective

Bidi is an inexpensive, low-processed, hand-rolled tobacco product. In Bangladesh, especially in Rangpur, tobacco farming and bidi processing are common. In this study, we aimed to evaluate the impact of bidi making on children working in bidi factories.

Methods

This qualitative(walk-through survey) and quantitative(questionnaire-based survey and a urine cotinine level quantitation) study was conducted in Rangpur, Bangladesh in 2017. Study population included child-workers aged ≤14 years who were regularly employed as bidi makers.

Findings

The results of the walk-through survey revealed hazardous working environments at bidi factories. For the quantitative survey, 171 child-workers were categorized into "less-working"(<5 hours/day) and "more-working"(≥5 hours/day) groups; additionally, "forced-working"(forced into work by parents) and "voluntary-working"(working voluntarily) groups were delineated within the same population. In the logistic regression analysis, odds ratios(ORs) of respiratory symptoms and unusual absence(absent ≥5 days/month) were higher in the "more-working" group than in the "less-working" group(unusual absence: OR, 2.91; 95% confidence interval[CI], 1.43-5.94), and this association became higher in the "forced-working" group with longer working hours(OR, 5.68, 95%CI 2.30-14.00).

Conclusions

Cheap, hand-rolled tobacco(bidi) is harmful to the health of bidi-making child-workers. Children in poverty bow to the demands of cheap labor and poverty and jeopardize their health and future prospects by working in bidi factories. Tobacco control policies should consider the social effects of tobacco beyond its biological effects.

Refinement of cg05575921 demethylation response in nascent smoking

The initiation of adolescent smoking is difficult to detect using carbon monoxide or cotinine assays. Previously, we and others have shown that the methylation of cg05575921 is an accurate predictor of adult smoking status. But the dose and time dependency of the demethylation response to smoking initiation in adolescents is not yet well understood. To this end, we conducted three consecutive annual in-person interviews and biological samplings of 448 high school students (wave 1 (W1)-wave 3 (W3)). At W1 (n = 448), 62 subjects reported using tobacco and 72 subjects reported using cannabis at least once in their life-time with 38 and 20 subjects having a positive cotinine and cannabinoid levels, respectively, at W1 intake. At W3 (n = 383), 67 subjects reported using tobacco and 60 subjects reported using cannabis at least once with 75 and 60 subjects having positive cotinine and cannabinoid levels, respectively, at W3. Subjects with undetectable cotinine levels at all three-time waves had stable levels of cg05575921 methylation throughout the study (88.7% at W1 and 88.8% at W3, n = 149), while subjects with positive cotinine levels at all 3 time points manifested a steady decrease in cg05575921 methylation (81.8% at W1 and 71.3% at the W3, n = 12). In those subjects with an affirmative smoking self-report at W3 (n = 17), the amount of demethylation at cg05575921 was correlated with time and intensity of smoking. We conclude that cg05575921 methylation is a sensitive, dose-dependent indicator of early stages of smoking, and may help to identify smokers in the early stages of smoking.

Sources and Biomarkers of Secondhand Tobacco Smoke Exposure in Urban Adolescents

OBJECTIVE

In an urban adolescent population, we evaluated sources of exposure to secondhand smoke exposure (SHS), examined differences in exposure by race/ethnicity, age and sex, and determined the relationship between exposure source(s) and the biomarkers cotinine and NNAL.

METHODS

Participants were recruited from a public hospital-based outpatient clinic in San Francisco, CA, USA.

RESULTS

Of a sample of N = 298 adolescents screened, 235 were biologically confirmed to be exposed to tobacco smoke. Of those, N = 16 were active smokers and N = 219 were exposed to SHS; 91 (39%) were heavily SHS exposed (median cotinine = 0.76 ng/mL) and 128 (54%) had light SHS exposure (median cotinine = 0.11 ng/mL). Within those SHS exposed, the most common source of exposure was in a public area. No significant racial/ethnic differences were found, although African American adolescents were more likely to live in a home that allowed smoking. Older adolescents were more likely to be exposed across several difference sources, and females more likely to be exposed in a car and in public areas. Past 7-day exposure in the home, in a car, and current blunt use were significantly related to biomarkers of exposure.

CONCLUSIONS

Urban adolescents are exposed to SHS across a variety of sources. Although exposure in a public area is most common, exposure in the home and in cars significantly influences tobacco biomarker levels. Interventions to reduce exposure would have the greatest impact in this population if they focused on reducing exposure in the home and in cars. History of blunt use is a strong determinant of tobacco exposure.

Electronic Health Record Classification of Tobacco Smoke Exposure and Cotinine Levels in Hospitalized Pediatric Patients

OBJECTIVES

Documentation of children's tobacco smoke exposure (TSE) in the electronic health record (EHR) can have important implications for clinical care. However, it may not be accurate if it is not based on biochemical assessment, the most reliable method of verifying TSE. Our objectives were to compare the accuracy of EHR classification of TSE with cotinine verification and to explore parent and child variables associated with biochemically verified TSE.

METHODS

Participants were 171 hospitalized pediatric patients (ages 0-17 years; mean age 5.1 [SD 3.7] years) who had EHR documentation of TSE and measured salivary cotinine. Children with cotinine levels >1 ng/mL were classified as having biochemical verification of TSE. Parents reported sociodemographic characteristics, and children's EHRs were abstracted for TSE status, past medical history, and diagnoses. We conducted χ² tests to assess the agreement between EHR classification of TSE status and cotinine levels. Then, we assessed the relationship between sociodemographic and clinical variables and cotinine using crude and adjusted logistic regression models.

RESULTS

Overall, 71% (121 of 171) of EHR classifications were correct on the basis of cotinine levels. Specificity analyses showed that 77% (53 of 69) were correctly identified as exposed to tobacco smoke. Sensitivity analyses showed that 67% (68 of 102) were correctly identified as unexposed. The negative predictive value was 0.61 (53 of 87); 39% (34 of 87) were misclassified as unexposed. The positive predictive value was 0.81 (68 of 84); 19% (16 of 84) were misclassified as exposed.

CONCLUSIONS

Almost 40% of children were misclassified in the EHR as unexposed to tobacco smoke. Biochemical verification should be used as part of universal TSE screening during pediatric hospitalizations.

Sources and Biomarkers of Secondhand Tobacco Smoke Exposure in Urban Adolescents

OBJECTIVE

In an urban adolescent population, we evaluated sources of exposure to secondhand smoke exposure (SHS), examined differences in exposure by race/ethnicity, age and sex, and determined the relationship between exposure source(s) and the biomarkers cotinine and NNAL.

METHODS

Participants were recruited from a public hospital-based outpatient clinic in San Francisco, CA, USA.

RESULTS

Of a sample of N = 298 adolescents screened, 235 were biologically confirmed to be exposed to tobacco smoke. Of those, N = 16 were active smokers and N = 219 were exposed to SHS; 91 (39%) were heavily SHS exposed (median cotinine = 0.76 ng/mL) and 128 (54%) had light SHS exposure (median cotinine = 0.11 ng/mL). Within those SHS exposed, the most common source of exposure was in a public area. No significant racial/ethnic differences were found, although African American adolescents were more likely to live in a home that allowed smoking. Older adolescents were more likely to be exposed across several difference sources, and females more likely to be exposed in a car and in public areas. Past 7-day exposure in the home, in a car, and current blunt use were significantly related to biomarkers of exposure.

CONCLUSIONS

Urban adolescents are exposed to SHS across a variety of sources. Although exposure in a public area is most common, exposure in the home and in cars significantly influences tobacco biomarker levels. Interventions to reduce exposure would have the greatest impact in this population if they focused on reducing exposure in the home and in cars. History of blunt use is a strong determinant of tobacco exposure.

Quantitative biochemical screening for marijuana use and concordance with tobacco use in urban adolescents

BACKGROUND

Assessing the prevalence and level of exposure (dose) of tobacco and marijuana use is important in studies of harm from use of these substances. We used biochemical analysis of urine to quantitatively assess exposure to nicotine and delta 9-tetrahydrocannabinol (THC) in adolescents receiving medical care in a public hospital METHODS: Participants were 686 adolescents between 12 and 21 years old seen at Zuckerberg San Francisco General Hospital between 2012 and 2014. Urine samples were assayed using high sensitivity liquid chromatographic assays for cotinine, a major metabolite of nicotine, and 11-nor-9-carboxy-delta 9-THC (THC-COOH), a major metabolite of THC. A commonly used immunoassay screen for THC-COOH was also performed.

RESULTS

The THC-COOH immunoassay substantially underestimated THC exposure, as measured with the high sensitivity assay. THC use was detected in 25% of participants, with higher prevalence with increasing age and in non-Hispanic blacks. Active tobacco smokers had an 80% prevalence of THC use (odds ratio for cigarette smoking predicting THC use 13.2). Urine cotinine and THC-COOH were significantly correlated (r = 0.60).

CONCLUSIONS

The use of a high sensitivity chromatographic urine assay provides a much more complete picture of adolescent tobacco use compared to a commonly used immunoassay. The immunoassay provides high specificity but moderate sensitivity. We confirm high concordance of tobacco and marijuana use and the high predictive value of cigarette smoking in predicting marijuana use, and provide novel data on the quantitative correlation between level of exposure to nicotine and THC. Quantitative screening of nicotine and THC exposure may enhance our understanding of addiction and harm from single and dual product use.

Area Deprivation as a Risk Factor for Methicillin-resistant Staphylococcus aureus Infection in Pediatric Cystic Fibrosis

BACKGROUND

In US cystic fibrosis (CF) patients, methicillin-resistant Staphylococcus aureus (MRSA) rates have tripled in the past 2 decades. Known clinical risk factors include exposure to a healthcare setting, Pseudomonas aeruginosa and CF-related diabetes. Area-level socio-environmental exposures have not been evaluated. We explored the association of area-level deprivation with MRSA prevalence in a pediatric CF Center in the Southeastern United States.

METHODS

Patients' residential addresses were geocoded and linked to a composite Area Deprivation Index and Rural-Urban Commuting Area scores. The association of MRSA with Area Deprivation Index and Rural-Urban Commuting Area scores was evaluated using logistic regression with robust standard errors adjusted for sociodemographic covariates (age, sex, race, mother's and father's education and household income), clinical risk factors (P. aeruginosa, CF-related diabetes, hospitalizations and number of clinic visits) and clustering.

RESULTS

The study included all pediatric patients (N = 231; mean age 12) at a single CF Center. MRSA was present in 44% of subjects. Higher area-level deprivation was correlated with rural residence, lack of parental college education and lower household income (P < 0.001 for each). In a multiple regression model fully adjusted for patient-level sociodemographic covariates, clinical risk factors and clustering, neighborhood deprivation was associated with more than 2-fold increase in the odds of having MRSA [OR 2.26 (1.14-4.45), P < 0.05].

CONCLUSIONS

Neighborhood deprivation is a risk factor for MRSA in pediatric CF, doubling the odds of infection. Community-level socioeconomic risk factors should be considered when developing prevention strategies and treatment plans for MRSA infection in pediatric patients with CF.

Association of passive smoking with dental caries and salivary biomarkers among 5-10 years old children of Muradnagar, Ghaziabad

Objectives:

The purpose of this study is to assess the association of passive smoking (PS) with dental caries and salivary biomarkers among 5–10 years old children of Muradnagar, Ghaziabad.

Methods:

A case–control study was conducted among 160 children of age group 5–10 years who visited the outdoor patient department of a dental college. Regular smoking households were recognized and children who lived in smoking households were identified as PS subjects. Two categories of children were formed – PS (80 children) and control group (80 children). Parents completed a pretested questionnaire and clinical examination of children was done using dmft index and gingival index. This was followed by collection of stimulated saliva of children which was further subjected to determine salivary buffering capacity and pH. Inoculation on mitis salivarius-bacitracin agar for counting streptococcus colonies and Rogosa SL agar (Difco) for counting lactobacillus colonies was done. Cotinine level was then measured using enzyme-linked immunosorbent assay kit. Student's independent t-test, Mann–Whitney U test, and one-way analysis of variance test were used for analyzing data.

Results:

The mean streptococcus and lactobacillus colony count was higher in PS case subjects, that is, 348.9 ± 166.509 and 247.3 ± 15.86 in comparison to control group where the mean streptococcus and lactobacillus colony count was 63.03 ± 23.082 and 63.825 ± 12.638, respectively. The mean cotinine level among PS case subjects was 1.08 ± 0.265 which was higher than the control group, that is, 0.00 ± 0.00. The mean cotinine level was directly proportional to streptococcus colonies, lactobacillus colonies, dmft and gingival index (GI) scores, and smoking exposure.

Conclusion:

PS has deleterious impact on children which was reflected by their increased cotinine levels, streptococcus colonies, lactobacillus colonies, and poor dmft and GI scores in comparison to the control group.

Comparison of Urine 4-(Methylnitrosamino)-1-(3)Pyridyl-1-Butanol and Cotinine for Assessment of Active and Passive Smoke Exposure in Urban Adolescents

Background: Many adolescents are exposed to tobacco smoke, from either active smoking (CS) or secondhand smoke (SHS) exposure. Tobacco-specific biomarkers of exposure include cotinine (detects use in past 2-4 days) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL; detects use for a month or longer). NNAL is expected to detect more intermittent tobacco exposure. We compared NNAL and cotinine as biomarkers of exposure to tobacco in urban adolescents and determined the optimal NNAL cutoff point to distinguish CS from SHS exposure.Methods: Surplus urine samples, collected from 466 adolescents attending pediatric well or urgent care visits at Zuckerberg San Francisco General Hospital in 2013 to 2014, were assayed for cotinine and NNAL.Results: Ninety-four percent of adolescents had measurable levels of NNAL compared with 87% for cotinine. The optimal NNAL cutoff point to distinguish CS from SHS was 9.6 pg/mL by latent class or 14.4 pg/mL by receiver-operating characteristic analysis. Cotinine and NNAL were strongly correlated, but the correlation slopes differed for active versus SHS-exposed adolescents. Among nonsmokers, NNAL levels were significantly higher in African American (median, 3.3 pg/mL) compared with other groups (0.9-1.9 pg/mL), suggesting greater exposure to SHS.Conclusions: Urine NNAL screening finds a large majority (94%) of urban adolescents are exposed to tobacco. African Americans are exposed to higher levels of SHS than other ethnic/racial groups.Impact: SHS is associated with significant medical morbidity in adolescents. Routine biochemical screening with NNAL or cotinine detects high prevalence of SHS exposure and should be considered as a tool to reduce SHS exposure in high-risk populations. Cancer Epidemiol Biomarkers Prev; 27(3); 254-61. ©2018 AACR.

Biosignature Discovery for Substance Use Disorders Using Statistical Learning

There are limited biomarkers for substance use disorders (SUDs). Traditional statistical approaches are identifying simple biomarkers in large samples, but clinical use cases are still being established. High-throughput clinical, imaging, and 'omic' technologies are generating data from SUD studies and may lead to more sophisticated and clinically useful models. However, analytic strategies suited for high-dimensional data are not regularly used. We review strategies for identifying biomarkers and biosignatures from high-dimensional data types. Focusing on penalized regression and Bayesian approaches, we address how to leverage evidence from existing studies and knowledge bases, using nicotine metabolism as an example. We posit that big data and machine learning approaches will considerably advance SUD biomarker discovery. However, translation to clinical practice, will require integrated scientific efforts.