Urinary Cotinine Concentrations Research Articles

Maternal Urinary Cotinine Concentrations During Pregnancy Predict Infant BMI Trajectory After Birth: Analysis of 89617 Mother-Infant Pairs in the Japan Environment and Children's Study.

BackgroundClinical or epidemiological conclusions remain undecided on the direct effects of active and second-hand smoking during pregnancy on childhood obesity. Urinary cotinine (UC) concentration, an accurate and quantitative marker for smoking, may elucidate the dose-dependent relationship between smoking during pregnancy and childhood obesity. To analyze the relationship between UC concentration and smoking questionnaire (SQ) classes for active and second-hand smoking in pregnant mothers and trajectory of infant Kaup index (body mass index: BMI).MethodsThis multicenter prospective cohort study was conducted using a list-wise complete set of 35829 among 89617 mother-infant singleton pairs, recruited between 2011 and 2014, in the Japan Environment and Children’s Study (JECS). Pairs were categorized according to UC levels (1 to 4 classes) or SQ (0 to 4 classes).ResultsMaternal BMI at delivery was the highest in UC class 4 (highest). Maternal and paternal education of ≥16 years and annual household income were lowest in UC class 4. Infant BMI was lower at birth, but trends in BMI and ΔBMI were higher from six to 36 months step-wise in the UC classes. The above tendency was observed in the list-wise complete dataset but was emphasized after multiple imputations and corrections of cofounders. UC concentration in five SQ classes largely fluctuated, and the relationship between SQ classes and trends in BMI and ΔBMI was not statistically significant.ConclusionInfants from high UC mothers had a low BMI at birth, increasing from six to 36 months of age. UC concentrations, but not smoking questionnaire classes, predict infant BMI trajectory, suggesting that active and second-hand smoking affect child obesity in a dose-dependent manner.

Assessing tobacco smoke exposure in pregnancy from self-report, urinary cotinine and NNAL: a validation study using the New Hampshire Birth Cohort Study

ObjectivesAccurate assessment of tobacco smoke exposure is key to evaluate its effects. We sought to validate and establish cut-offs for self-reported smoking and secondhand smoke (SHS) exposure during pregnancy using...

Dose–response relationships between maternal urinary cotinine and placental weight and ratio of placental weight to birth weight: The Japan Environment and Children's Study

IntroductionStudies on the relationship between maternal self-reported smoking status and placental weight report inconsistent results. This study examined the relationships between maternal urinary cotinine concentration and placental weight and the ratio of placental weight to birth weight (PW/BW ratio). The study also examined the relationship between maternal smoking status, as determined by cotinine concentration, with placental weight and with PW/BW ratio, stratified by sex of offspring. MethodsOur analysis used information of 91,049 mother–child pairs enrolled in the Japan Environment and Children's Study. Maternal urinary cotinine concentration was quantified (during the second or third trimester) with high-performance liquid chromatography-tandem mass spectrometry. Using restricted cubic splines, placental weight and PW/BW ratio were plotted against natural log-transformed cotinine concentration. Taking cotinine levels of <0.17 ng/mL, 0.17 to <21.5 ng/mL (natural log-transformed values, −1.77 to 3.07), and ≥21.5 ng/mL as indicative of non-smokers, passive smokers, and active smokers, respectively, the relationships between maternal smoking status and placental weight and PW/BW ratio were examined, adjusting for confounders. ResultsPlacental weight and PW/BW ratio increased with increasing cotinine concentration. After cotinine reached a certain concentration, the placental weight decreased in male offspring whereas it plateaued in female offspring. Compared with not smoking, active smoking during pregnancy significantly increased placental weight and PW/BW ratio. ConclusionPlacental weight responded as an inverted U-shape whereas the PW/BW ratio followed a J-shape with increasing maternal urinary cotinine concentration measured during pregnancy, suggesting exposure to tobacco smoke induces a disproportionate reduction in fetal growth. The effect of tobacco smoke on placental growth varied by sex of offspring.

The importance of smoking cessation during pregnancy and its association with perinatal outcomes

Abstract In utero exposure to tobacco smoke is associated with an increased risk of multiple adverse perinatal outcomes. Smoking cessation during pregnancy has been related to the improvement of these outcomes, but often relies on self-reporting, impairing an accurate assessment of smoking cessation impact on newborńs health. Building on data obtained in the frame of the NEOGENE project, this work aimed to estimate the association between smoking cessation among pregnant women, confirmed by maternal urinary cotinine concentrations, and perinatal outcomes. The study population included 595 pregnant women who sought prenatal care in a public hospital in Porto (Portugal), from April 2017 to July 2018. Data on tobacco consumption and cessation was obtained in a face-to-face interview, during the hospital stay. Perinatal outcomes, namely birth weight (BW), length (BL) and head circumference (HC) were retrieved from the hospital medical records. Maternal self-reported tobacco use was validated by urinary cotinine concentrations, using the solid-phase competitive ELISA technique. Maternal active smoking was associated with a significant decrease in BW, BL and HC of 157.66 g (p &amp;lt; 0.001), 0.78 cm (p = 0.001) and 0.39 cm (p = 0.016). Notably, maternal smoking cessation led to a significant increase in BW of approximately 172 g (p = 0.006), when compared to mothers who have not ceased. Increases in BL and HC did not reach significance. This study upholds that tobacco consumption is still an important public health threat in Portugal and that smoking cessation during pregnancy reverses smoking-associated deficits in perinatal outcomes, emphasizing the crucial need for awareness campaigns to promote smoking cessation during pregnancy. Acknowledgments: This work was supported by FCT and FAPESP (FAPESP/19914/2014). AIS, JM and CC also acknowledge FCT for individual funding (SFRH/BD/145101/2019, SFRH/BPD/115112/2016 and SFRH/BPD/96196/2013 grants, respectively). Key messages Maternal active smoking was significantly associated with lower birth weight, length and head circumference. Maternal smoking cessation reverses the smoking-associated deficits in birth weight.

High-resolution metabolomics of exposure to tobacco smoke during pregnancy and adverse birth outcomes in the Atlanta African American maternal-child cohort

Exposure to tobacco smoke during pregnancy has been associated with a series of adverse reproductive outcomes; however, the underlying molecular mechanisms are not well-established. We conducted an untargeted metabolome-wide association study to identify the metabolic perturbations and molecular mechanisms underlying the association between cotinine, a widely used biomarker of tobacco exposure, and adverse birth outcomes. We collected early and late pregnancy urine samples for cotinine measurement and serum samples for high-resolution metabolomics (HRM) profiling from 105 pregnant women from the Atlanta African American Maternal-Child cohort (2014–2016). Maternal metabolome perturbations mediating prenatal tobacco smoke exposure and adverse birth outcomes were assessed by an untargeted HRM workflow using generalized linear models, followed by pathway enrichment analysis and chemical annotation, with a meet-in-the-middle approach. The median maternal urinary cotinine concentrations were 5.93 μg/g creatinine and 3.69 μg/g creatinine in early and late pregnancy, respectively. In total, 16,481 and 13,043 metabolic features were identified in serum samples at each visit from positive and negative electrospray ionization modes, respectively. Twelve metabolic pathways were found to be associated with both cotinine concentrations and adverse birth outcomes during early and late pregnancy, including tryptophan, histidine, urea cycle, arginine, and proline metabolism. We confirmed 47 metabolites associated with cotinine levels, preterm birth, and shorter gestational age, including glutamate, serine, choline, and taurine, which are closely involved in endogenous inflammation, vascular reactivity, and lipid peroxidation processes. The metabolic perturbations associated with cotinine levels were related to inflammation, oxidative stress, placental vascularization, and insulin action, which could contribute to shorter gestations. The findings will support the further understanding of potential internal responses in association with tobacco smoke exposures, especially among African American women who are disproportionately exposed to high tobacco smoke and experience higher rates of adverse birth outcomes.

Telomere length and urinary 8-hydroxy-2’-deoxyguanosine and essential trace element concentrations in female Japanese university students

Telomere length is thought to be a biomarker of biological aging. This study examined whether telomere length was associated with urinary concentrations of 8-hydroxy-2’-deoxyguanosine (8-OHdG), a biomarker of oxidative stress, and antioxidative trace elements in 73 female Japanese university students (age: 19.2 ± 0.7 years). We quantified 8-OHdG and selenium in urine by liquid chromatography–mass spectrometry and inductively coupled plasma-mass spectrometry, respectively. Telomere length and urinary concentrations of other essential trace elements (molybdenum, cobalt, and chromium) that were previously measured in the same study participants, were used in this study. We used multiple linear regression analysis to examine the associations of telomere length with urinary 8-OHdG and essential trace element concentrations (covariates: urinary cotinine concentration, age, BMI, and drinking status). The geometric means (geometric standard deviation) of 8-OHdG and selenium were 3.4 (1.5) and 31 (1.3) µg/g creatinine, respectively. Telomere length was not associated with urinary 8-OHdG concentration, but was negatively associated with urinary selenium concentration. In conclusion, telomere length was not associated with urinary 8-OHdG concentration in the young women in this study. Longitudinal studies should be conducted to clarify the association between telomere shortening rate and oxidative stress level.

Clinical Observation of Auricular Acupressure Combined with Transcranial Direct Current Stimulation for Nicotine Dependence

<sec><title>Objective</title> To observe the clinical effect of auricular acupressure combined with transcranial direct current stimulation (tDCS) for nicotine dependence. </sec><sec><title>Methods</title> A total of 90 patients with nicotine dependence were divided into three groups (combination group, tDCS group and auricular acupressure group), using the method of random number table, with 30 cases in each group. In the auricular acupressure group, vaccaria segetalis were applied at the point representing the lung,stomach, shenmen, mouth, pizhixia and heart. The patients were asked to self-administrate auricular acupressure for two minutes per session, five times a day. When the desire to smoke was strong, patients were adviced to press and pinch it for 3 minutes. In addition, the auricular acupressure pads were changed every 2 days, three times per week, for four weeks. In the tDCS group, tDCS was applied at the dorsolateral prefrontal cortex, 1.4 mA in intensity, 20 min each time, three times per week, for four weeks. In the combination group, we applied the auricular acupressure combined with tDCS and the methods were the same as the tDCS group and the auricular acupressure group. Before treatment and 2, 4 weeks after treatment, the smoking frequency a day, Fagerström test of nicotine dependence (FTND) score, the questionnaire of smoking urges (QSU) score, Minnesota nicotine withdrawal scale (MNWS) score and the concentration of cotinine in urine were observed in all three groups. </sec><sec><title>Results</title> There was no significant difference in daily smoking frequency, FTND score, QSU score, MNWS score and cotinine concentration in urine before treatment (<italic>P</italic><0.05). Compared with before treatment, the daily smoking frequency of each group decreased after 4 weeks of treatment (<italic>P</italic><0.05); the daily smoking frequency of the combination group was (8.50±3.60), which was better than that of the tDCS group (11.16±4.29) and the auricular acupressure group (12.83±3.39) (<italic>P</italic><0.05); at 4 weeks of follow-up period, the daily smoking frequency in the combination group was (10.38±4.56), which was better than that in the tDCS group (13.76±5.87) and the auricular acupressure group (15.65±6.25) (<italic>P</italic><0.05). Compared with before treatment, FTND score, MNWS score and QSU score in each group decreased after 4 weeks of treatment (<italic>P</italic><0.05); the FTND score of the combination group was (1.46±1.41), which was better than that of the tDCS group (2.70±2.03) and the auricular acupressure group (2.83±1.23) (<italic>P</italic><0.05); the MNWS score of the combination group was (4.73±3.16), which was better than that of the tDCS group (6.33±3.38) and the auricular acupressure group (6.96±2.09) (<italic>P</italic><0.05); the QSU score of the combination group was (12.70±3.15), which was better than the tDCS group (15.86±5.34) and the auricular acupressure group (16.60±6.71) (<italic>P</italic><0.05). Compared with before treatment, the concentration of cotinine in urine of each group decreased after 4 weeks of treatment (<italic>P</italic><0.05); the concentration of cotinine in urine in the combination group was (11.42±6.33), which was better than that in the tDCS group (18.23±8.54) and the auricular acupressure group (20.74±9.04) (<italic>P</italic><0.05). </sec><sec><title>Conclusion</title> Auricular acupressure combined with tDCS could reduce daily smoking frequency, decrease tobacco dependence and smoking craving, and alleviate withdrawal symptoms. Its efficacy is better than auricular acupressure alone or tDCS treatment alone, and this treatment is of great value to promotion. </sec>

Urinary cotinine assessment of maternal smoking and environmental tobacco smoke exposure status and its associations with perinatal outcomes: a cross-sectional birth study

Tobacco consumption and environmental tobacco smoke (ETS) exposure remains an important public health concern. Pregnant women require particular attention as active and passive smoking during pregnancy are associated with multiple adverse perinatal outcomes. This study aimed to biochemically validate self-reported smoking and ETS exposure status among pregnant women, to more precisely ascertain its association with adverse perinatal outcomes. Data refers to 595 pregnant women who sought prenatal care in a public hospital in Porto, Portugal. A standard questionnaire on smoking and ETS-related variables was completed. Urinary cotinine (UC) concentrations were assessed by solid-phase competitive ELISA, in maternal urine samples collected on the day of delivery. The results showed that the optimal UC cut-off value to distinguish smokers from non-smokers and within non-smokers those who were exposed to ETS from those non-exposed in the third trimester of pregnancy was 74.1 ng/mL (sensitivity and specificity of 96.7% and 98.0%, respectively) and 1.6 ng/mL (sensitivity of 66.2% and specificity of 75.7%, respectively). The agreement between maternal self-reported and UC-based smoking status was very good (κ=0.919, p<0.001), but much lower for ETS exposure (κ=0.386, p<0.001). Maternal active smoking in the third trimester of pregnancy was associated with a significant decrease in birth weight, length and head circumference of 157.66 g (95% CI: −245.81, −69.52; p<0.001), 0.78 cm (95% CI: −1.22, −0.34; p=0.001) and 0.39 cm (95% CI: −0.70, −0.07; p=0.016), respectively. Maternal ETS exposure in the third trimester of pregnancy was associated with a non-significant increase in birth weight of 38.37 g (95% CI: −28.91, 105.64; p=0.263). Furthermore, maternal smoking cessation was associated with the increase of approximately 172 g in birth weight (95% CI: 50.00, 293.19). As such, there is an urgent need for increased public health awareness campaigns to encourage smoking cessation during pregnancy, in order to improve perinatal outcomes.

Association between urine cotinine and depressive symptoms in non-smokers: National representative sample in Korea

BackgroundSecondhand smoke (SHS) exposure is known to have negative effects on mental as well as physical health. However, the association between SHS and mental health problems has not been assessed in non-smokers. To evaluate the association of exposure to tobacco smoke and depressive symptoms, and that of the prevalence of having depressive symptoms and urinary cotinine (UCo) concentrations in non-exposed subjects. MethodsData was extracted from the Korea National Health and Nutrition Examination Survey (KNHANES). Depressive symptoms were determined based on a patient's overall score on the Patient Health Questionnaire (PHQ)-9, and SHS exposure was evaluated using self-reported data and UCo concentration. Overall, 13,219 non-smokers, ≥ 19 years were included in the study. Multinomial logistic regression analysis was conducted to identify factors related to depressive symptoms; independent t-test was conducted to confirm the differences in UCo concentration according to the prevalence of depression. ResultsAmong the non-exposure groups, 2.0% of the males and 5.6% of the females showed depressive symptoms. Lower social-economic status, higher UCo concentration, and SHS exposure increased the prevalence of depressive symptoms. The UCo concentration of females with depressive symptoms was significantly higher than those of females without depressive symptoms. LimitationsThis study only demonstrated an association between SHS exposure and depression, not the causal effects, because of the cross-sectional study design. ConclusionSHS exposure and depressive symptoms are correlated. The association was also confirmed by evaluating the UCo concentration of those who were not exposed to SHS based on self-reported data.

Characterization of urinary cotinine concentrations among non-smoking adults in smoking and smoke-free homes in the Korean national environmental health survey (KoNEHS) cycle 3 (2015\u20132017)

BackgroundAlthough many indoor public places have implemented smoke-free regulations, private homes have remained sources of tobacco smoke pollutants. This study examined differences in urinary cotinine concentrations in the Korean non-smoking adult population between living in smoking and smoke-free homes, and the relationship of urinary cotinine concentrations with socio-demographic factors in smoke-free homes.MethodsSamples from 2575 non-smoking adults (≥19 years old) in the Korean National Environmental Health Survey cycle 3 (2015–2017), a representative Korean study, were used. Smoking and smoke-free homes were defined based on whether there were smokers at homes. Weighted linear regression models were used to determine urinary cotinine concentrations and identify factors associated with urinary cotinine.ResultsThe geometric mean of urinary cotinine concentrations for non-smoking adults living in smoking homes was 2.1 μg/L (95% confidence interval [CI] = 1.8–2.4), which was significantly higher than the mean of 1.3 μg/L (95% CI = 1.2–1.4) for those living in smoke-free homes. Urinary cotinine concentrations were different significantly by home smoking status in most socio-demographic subgroups. Data from smoke-free home showed urinary cotinine concentration in adults was significantly higher in those who lived in homes with ventilation duration < 30 min/day, those who spent more time indoors at home, those who spent less time outdoors, and those who worked in non-manual or manual occupations.ConclusionsThe urinary cotinine concentration in Korean non-smoking adults living in smoking homes was higher than that in adults living in smoke-free homes. Even in smoke-free homes, home-related factors, such as ventilation duration and time spent indoors, were associated with urinary cotinine concentration. Further study is warranted to examine potential sources of tobacco smoke pollution in smoke-free homes.

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

BackgroundAs 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.ObjectiveWe 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.MethodsMultivariable 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.ResultsAlthough 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.SignificanceThough 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.

Thirdhand smoke exposure: Differences in smoke exposure indices and cultural norms between hotels and motels in South Korea

The legal regulations and cultural environment for smoking bans in hotels and motels in South Korea differ depending on the type of accommodation. The aim of this study was to assess the thirdhand smoke exposure for hotel and motel guests staying at accommodations who are expected to be relatively vulnerable to thirdhand smoke. Biomarkers for 28 participants were assessed before and after lodging at a hotel or motel for approximately 14 h. Hotel participants had statistically decreased urinary cotinine concentrations after their stay, whereas motel participants experienced increased concentrations. The concentration of nicotine-derived nitrosamine ketone in dust in hotels was lower than that in motels, and the higher dust nicotine-derived nitrosamine ketone concentration in motels had more effect on an increase in urinary cotinine concentration. Both hotels and motels legally allowed smoking in guest rooms. However, the study participants in hotels were less exposed to thirdhand smoke than those in motels.

Effects on Smoking Behavior of Switching Menthol Smokers to Non-menthol Cigarettes.

Bans of menthol characterizing flavor in cigarettes have been implemented in some localities and have been proposed more broadly. One proposed benefit of such a ban is to increase cessation rates among current menthol smokers. There is currently relatively limited data regarding how smoking behavior changes if menthol smokers switch to non-menthol cigarettes. African American menthol smokers interested in quitting smoking were randomized to either continue smoking menthol (n = 60) or switch to non-menthol cigarettes (n = 62) for 1 month prior to a cessation attempt. Cessation results were reported previously; this analysis reports the results from the pre-cessation visits at which amount smoked, exhaled carbon monoxide (CO) concentration, urinary cotinine concentrations, and subjective measures were assessed. Over the 4-week study period, those switching to non-menthol (vs. continuing to smoke menthol) cigarettes smoked fewer cigarettes per day (mean ratio: 0.86; 95% confidence interval [CI]: 0.76, 0.98; p = .02), reported lower withdrawal symptom severity (mean difference -1.29; 95% CI: -2.6 to -0.01; p = .05) and higher perceived effectiveness of their skills for quitting smoking (mean difference 0.56; 95% CI: 0.02-1.10; p = .05). No significant differences were found between groups in exhaled CO, urinary cotinine concentrations, or most other subjective effects including support for a ban on menthol characterizing flavor in cigarettes. These results suggest that were menthol cigarettes no longer available, those that switch to non-menthol cigarettes would not change their smoking behavior in a way that is likely to be more hazardous, with some indicators suggesting that there may be some benefit.Clinicaltrials.gov # NCT02342327. A ban on menthol characterizing flavor in cigarettes has been proposed as a potential means by which to increase smoking cessation rates among current menthol cigarette smokers. This study evaluated how African American menthol cigarette smokers adjusted their smoking behavior after switching to non-menthol cigarettes. Although the overall differences between groups were modest, they were in a direction consistent with decreased smoking suggesting that current smokers would not adjust their behavior in a way that is likely to be more hazardous, with some indicators suggesting that there may be some benefits.

Effect of parental smoking on their children's urine cotinine level in Korea: A population-based study.

BackgroundChildren may be exposed to tobacco products in multiple ways if their parents smoke. The risks of exposure to secondhand smoke (SHS) are well known. This study aimed to investigate the association between parental smoking and the children’s cotinine level in relation to restricting home smoking, in Korea.MethodsUsing the Korea National Health and Nutrition Health Examination Survey data from 2014 to 2017, we analyzed urine cotinine data of parents and their non-smoking children (n = 1,403), in whose homes parents prohibited smoking. We performed linear regression analysis by adjusting age, sex, house type, and household income to determine if parent smoking was related to the urine cotinine concentration of their children. In addition, analysis of covariance and Tukey’s post-hoc tests were performed according to parent smoking pattern.FindingChildren’s urine cotinine concentrations were positively associated with those of their parents. Children of smoking parents had a significantly higher urine cotinine concentration than that in the group where both parents are non-smokers (diff = 0.933, P < .0001); mothers-only smoker group (diff = 0.511, P = 0.042); and fathers-only smoker group (diff = 0.712, P < .0001). In the fathers-only smoker group, the urine cotinine concentration was significantly higher than that in the group where both parents were non-smoker (diff = 0.221, P < .0001), but not significantly different compared to the mothers-only smoker group (diff = - -0.201, P = 0.388). Children living in apartments were more likely to be exposed to smoking substances.ConclusionThis study showed a correlation between parents’ and children’s urine cotinine concentrations, supporting the occurrence of home smoking exposure due to the parents’ smoking habit in Korea. Although avoiding indoor home smoking can decrease the children’s exposure to tobacco, there is a need to identify other ways of smoking exposure and ensure appropriate monitoring and enforcement of banning smoking in the home.

A new method for the simultaneous determination of urinary NNAL and cotinine concentrations using HILIC-MS/MS coupled with PRiME HLB SPE

Urinary cotinine and NNAL are the biomarkers of tobacco smoke exposure and tobacco specific nitrosamines (TSNAs), respectively. A new method for the simultaneous analysis of them by hydrophilic interaction liquid chromatography tandem mass (HILIC-MS/MS) combined with PRiME HLB solid phase extraction (SPE) was developed. The sample matrix was removed effectively with PRiME HLB SPE and HILIC separation. The linearities were good in a range of 5.00-3.00 × 103 ng/L for NNAL and 0.200-4.00 × 102 μg/L for cotinine. The method detection limit of NNAL (0.0580 ng/L) was better than that in other literatures, and 0.0240 μg/L for cotinine. Recoveries were 91.6-110% and 88.7-113% with relative standard deviations of 3.78-9.12% and 0.120-1.15% for NNAL and cotinine, respectively. 29 urine samples were detected by the established method. The contents of NNAL and cotinine were 0.590-66.7 ng/g·Cr and 2.86-1.34 × 103 μg/g·Cr, respectively. Moreover, the results showed that urinary NNAL and cotinine were significantly positive correlation, even in passive smokers.

Passive Smoking and Pediatric Dental Caries

Background: Dental caries is a chronic dental disorder of children and it can result in substantial morbidity due to pain, dysfunction, poor appearance, and problems of speech development. The study was conducted to assess the association between passive smoking and pediatric dental caries.&#x0D; Methods: The cross-sectional study was conducted among 92 school children aged 5-10 years. Data on exposure to passive smoking at both indoor and outdoor were obtained through face to face interview of the parents with the help of semi-structured questionnaire and checklist. Dental caries was diagnosed by clinical examination and passive smoking exposure was assessed by estimated urinary cotinine level.&#x0D; Results: The study revealed that 58.70% children were male and 41% were female respectively. The mean age of the children was 7.20 years. It was found that 59.8% father of the studied children were smoker where 68.5% children reported that some of their family members were indoor smokers. Of all the children, 62% had dental caries and 85.5% of the children had dental caries who were exposed to passive smoking and had significant association between exposure to passive smoking and dental caries (p&lt;0.001). Dental caries was common among children aged 5-6years who were exposed to passive smok ing. The mean urinary cotinine level was 27.81 ng/ml and maximum children (65.2%) had urinary cotinine level more than 10ng/ml who was exposed to passive smoking. The study found significant positive correlation between urinary cotinine concentrations and the duration of exposure to passive smoking (i=0.692, p&lt;0.001).&#x0D; Conclusion: This study suggests reduction of exposure to passive smoking may be an effective measure for prevention of pediatric dental caries.&#x0D; JOPSOM 2020; 39(1): 1-13

Introducing Machine Learning to Environmental Health Research; Exploring Random Forest in Prediction Modeling

BackgroundAccurately assessing tobacco smoke exposure in early life is important to understanding and preventing childhood asthma. In populations with relatively low smoking exposure, it becomes challenging to characterize the main exposure sources of tobacco smoke exposure. When creating a prediction model of questionnaire items to explain variability in nicotine metabolite concentrations, traditional approaches include using directed acyclic graphs, change-in-estimate procedure, comparing AIC and/or R2 statistics, and stepwise selection. These approaches may be improved upon with machine learning. MethodsUsing the CHILD Cohort Study, we measured urinary concentrations of nicotine biomarkers (cotinine and trans-3’-hydroxycotinine (3HC)) at low detection levels (0.03ng/mL) and questionnaire responses related to smoking and other lifestyle factors. Urine samples were collected along with questionnaires at 3-4 months of age. The concentrations were corrected for specific gravity. Random forest regression was used to assign variable importance scores to questionnaire items based on how well they predicted the urinary cotinine and 3HC concentrations. Combining knowledge from this machine learning technique with traditional model selection strategies, a multivariable linear regression prediction model was selected to assess how well questionnaires explained urinary cotinine and 3HC concentrations. Results76% and 89% of the infants had detectable urinary cotinine and 3HC levels, with the geometric mean levels consistent with light or intermittent second-hand smoke, third-hand smoke or possibly from diet. Final models explained 32% and 41% of cotinine and 3HC concentration variation in our sample (n=2,017). Questions related to prenatal smoking exposure, second-hand smoke, housing, breastfeeding, and socioeconomic factors were most important in predicting urinary concentrations at 3 months. ConclusionsTo facilitate complex exposure assessment in interdisciplinary projects, researchers have more sensitive tools from outside their traditional disciplines to improve models and generate new hypotheses. Variable importance plots are a relatively easy and interpretable way to incorporate machine learning into environmental health research.

Trends in Secondhand Smoking and Urine Cotinine Concentration in Non-Smoking Adults in Korea: The 2008–2011, 2014–2018 Korea National Health and Nutrition Examination Survey

Trends in Secondhand Smoking and Urine Cotinine Concentration in Non-Smoking Adults in Korea: The 2008–2011, 2014–2018 Korea National Health and Nutrition Examination Survey

Determination of Urinary Cotinine Cut-Off Concentrations for Pregnant Women in the Japan Environment and Children's Study (JECS).

Few studies have assessed the accuracy of self-reported questionnaires to determine smoking habits relative to urinary biomarkers. This study investigated urinary cotinine cut-off concentrations distinguishing active, passive and non-smokers among pregnant women who participated in the Japan Environment and Children’s Study, a nationwide birth cohort study. Pregnant participants with measured urinary cotinine concentrations (UCCs) and who completed self-reported questionnaires on smoking status were included (n = 89,895). The cut-off values (COVs) for active and passive smokers were calculated by fitting mixed normal distribution functions to UCCs. The sensitivity and specificity of the questionnaires were subsequently evaluated. The median (interquartile range) UCC was 0.24 (0.083–0.96) µg/g-creatinine, with the detection rate of 89%. The COV for distinguishing active smokers from passive and non-smokers was 36.8 µg/g-creatinine. When this COV was considered to represent the true condition, the questionnaire had a sensitivity of 0.523, a specificity of 0.998, a positive predictive value (PPV) of 0.967 and a negative predictive value (NPV) of 0.957. The COV for distinguishing passive smokers from non-smokers was 0.31 µg/g-creatinine, with the questionnaire having a sensitivity of 0.222, a specificity of 0.977, a PPV of 0.868 and an NPV of 0.644. As many as 78% of passive smokers might be misclassified as non-smokers.

Are Urine Propylene Glycol or Vegetable Glycerin Markers of E-cigarette Use or Abstinence?

Urine propylene glycol (PG) and vegetable glycerin (VG) were evaluated as potential markers for discriminating ECIG users from non-users and verifying ECIG abstinence. Urine samples from 51 ECIG users (collected pre/post 12-hours ECIG abstinence), and 50 controls (who do not use nicotine/tobacco) were analyzed for urine cotinine, PG, and VG concentration. Of 42 ECIG users with pre-abstinence urine cotinine indicating nicotine use, mean (SD) urine cotinine concentration was 1053.7 ng/ml (874.5) and for controls was 1.93 ng/ml (0.4); after abstinence, ECIG users' mean cotinine decreased to 615.4 ng/ml (753.0). For ECIG users, mean urine PG pre-abstinence was 25.6 mcg/ml (20.0) and was 9.8 mcg/ml (13.5) for controls; after abstinence, ECIG users' mean urine PG decreased to 9.7 mcg/ml (15.0; ps < .05). For ECIG users, mean urine VG pre-abstinence was 7.5 mcg/ml (7.1) and was 13.2 mcg/ml (25.0) for controls; after abstinence, ECIG users' mean VG decreased to 5.0 mcg/ml (4.4; ps < .05). ECIG users' mean urine PG was greater than controls and decreased after 12-hours ECIG abstinence suggesting urine PG may be useful for discriminating ECIG users from non-users and verifying short-term abstinence.