Urinary Cotinine as a Biomarker of Cigarette Smoke Exposure: A Method to Differentiate Among Active, Second-Hand, and Non-Smoker Circumstances

Method Validation for the Determination of Nicotine and Nicotine Metabolite Levels in Urine, Serum, and Saliva Samples

Monitoring nicotine and its metabolites in bodily fluids is crucial for assessing tobacco exposure and related toxicity in clinical practice. Due to its high sensitivity for detecting low-level analytes, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed to enhance a robust and accurate analytical procedure for quantifying nicotine and its derivatives in serum, urine, and saliva. Comparative analysis was conducted on samples collected from individuals with and without smoking habits. The LC-MS/MS method utilized an API 3200 triple quadrupole instrument paired with a Phenomenex Luna C18 column. Method sensitivity was demonstrated through evaluation of sensitivity parameters, including LOD and LLOQ for each analyte in all matrices. Inter-assay variability and bias values at the LLOQ level were kept below 20%. In serum, the LOD-LLOQ ranges were 0.02-0.05 μg/L for nicotine, 0.32-0.95 μg/L for cotinine, 0.07-0.25 μg/L for 3-OH cotinine, and 0.22-0.69 μg/L for norcotinine. In urine, the respective values were 0.03-0.10, 0.23-0.82, 0.06-0.14, and 0.20-0.55 μg/L, and in saliva, the values were 0.12-1.59, 0.22-2.34, 0.10-0.17, and 0.33-3.01 μg/L. The proposed method is efficient, specific, and adaptable to routine clinical workflows, providing a valuable tool for monitoring tobacco-related exposure.

Determination of Cotinine, 3'-Hydroxycotinine and Nicotine 1'-Oxide in Urine of Passive and Active Young Smokers by LC-Orbitrap-MS/MS Technique

Tobacco smoke is probably the most significant factor conducing to toxic xenobiotics exposure to humans. The aim of the study was to develop a rapid and sensitive method for the determination of selected nicotine metabolites in urine of tobacco smokers and passive smokers. The method for removing protein and extracting the metabolites involved the centrifugation of urine with acetonitrile. Cotinine, trans-3'-hydroxycotinine, and (2'S)-nicotine 1'-oxide in the supernatant were determined using the LC-Orbitrap-MS/MS technique, with the selected ion monitoring (SIM) and parallel reaction monitoring (PRM) modes used. The recovery of these analytes added to the urine samples ranged from 72% to 101%. Repeatability and reproducibility were less than 3.1% and 10.1%, respectively. The study was carried out among medical students. The group was selected as representatives of young people and who as future physicians should be more aware of the effects of nicotine use. Concentration levels of cotinine and trans-3'-hydroxycotinine determined in ng/mL in the urine of cigarette smokers were 70- and 58-fold higher, respectively, compared to passive smokers. Higher concentrations were recorded in the urine of those passively exposed to tobacco smoke than in non-smokers, confirming that passive exposure to tobacco smoke is not harmless to the human body. However, no significant differences were observed in the concentration of (1'S,2'S)-nicotine 1'-oxide in the samples of individuals from various groups.

Evaluation on the Sex-Specific Association Between Cigarette Smoke Exposure and Inflammation Markers-C-Reactive Protein and White Blood Cell Count

INTRODUCTION

Cigarette smoke increases peripheral white blood cell (WBC) count. However, the dose-dependent association between smoking and C-reactive protein (CRP), an important inflammatory marker, has been reported as inconsistent.

AIMS AND METHODS

Here, we evaluated the associations between smoking and CRP using both smoking questionnaires and urine cotinine as exposure markers. The Korea National Health and Nutrition Examination Survey data were used for analyzing the associations. Multiple regression analyses were performed to examine the associations between cigarette smoke exposure, as assessed by questionnaires and urine cotinine, and health effects, as measured by CRP and WBC count, controlling for potential confounders. The confounders, including age, sex, body mass index, blood pressure, cholesterol, glucose, alanine aminotransferase, and uric acid, were selected a priori based on the literature.

RESULTS

A total of 11 435 participants were included for analysis. For the exposure-response relationship, the results indicated a significant increase in CRP levels in male smokers compared to male nonsmokers (p = .002), whereas no significant increase was found in female smokers compared to female nonsmokers (p = .680). For the dose-response relationship, a significant positive association was observed between urine cotinine and CRP in male smokers (p = .018), whereas no significant association was found in female smokers (p = .508). WBC count consistently showed significant exposure-response and dose-response relationships in both sexes.

CONCLUSIONS

WBC count was found to be a consistent effect marker of cigarette smoke exposure, while the association between CRP level and smoking was inconsistent and varied by sex. The sex-specific response to cigarette smoke exposure warrants further exploration in future studies.

IMPLICATIONS

Cigarette smoke exposure is known to increase inflammation and has been thought to increase CRP, a significant inflammation marker. However, recent studies have reported conflicting results regarding the dose-dependent association between cigarette smoke exposure and CRP. This study found that the association between smoking and CRP is inconsistent and varies by sex, showing significant exposure response in men but not in women. Furthermore, the study suggests that WBC count is a more consistent marker for cigarette smoke exposure.

Household smoking impact on the oral health of 5- to 7-years-old children

BACKGROUND

Children's exposure to secondhand smoke, particularly by their parents, could adversely affect their oral health. Thereby, this study aimed to assess the oral health status of children subjected to household smoking and the impact of smoking patterns on the severity of oral health deterioration.

METHODS

A total of 210 healthy children were enrolled in this case-control study and allocated into children subjected to household smoking (HS) and control groups. Participants' guardians were asked to complete a questionnaire regarding sociodemographic characteristics and parental smoking habits. All participants were subjected to clinical dental examination to assess dental caries (ICDAS), hypomineralized primary molars (HSPM), and gingival status (GI). Stimulated saliva samples were collected to assess saliva composition and characteristics. Urine samples were collected and analyzed for cotinine concentration. Data were analyzed using SPSS (v.25) software at a test value of p ≤ 0.05. The t-student test was used to find significant differences between participants' age, gingival index score, saliva pH, flow rate, sIgA, and cotinine level. The Chi-square test was used to test for the significance of parental employment, number of rooms, gender, sweets consumption, brushing frequency, and HMPM. The correspondence analysis was used to test for significance of parents' levels of education, type of house ventilation, ICDAS score, smoking form, frequency, and smoking pattern. The correlation between cotinine level and sIgA was tested for association using Bivariate correlation test.

RESULTS

The HS group showed a significantly increased risk for dental caries (p < 0.000), HSPM lesions (p = 0.007), and GI score (p < 0.000). A significant reduction in salivary flow rate, saliva pH, and sIgA were evident in HS group (p < 0.000). Parental consumption of more than 20 cigarettes/day was accompanied by increased dental caries activity (p < 0.000) and higher risk for increased severity of gingival inflammation (p < 0.000) of children in the HS group. Children of parents who smoke cigarettes and use the hubble/bubble anywhere in the house found to have greater distribution of HSPM (p < 0.000). Reduced sIgA values were found to be significantly associated with increased cotinine concentrations in HS children (p < 0.000).

CONCLUSIONS

Frequent exposure to household smoking could be associated with an increased risk of dental caries progression, enamel hypomineralization, gingival inflammation, and saliva characteristics changes in children.

Urinary Metals, Arsenic, and Polycyclic Aromatic Hydrocarbon Exposure and Risk of Self-reported Emphysema in the US Adult Population

PURPOSE

Metal and chemical exposure can cause acute and chronic respiratory diseases in humans. The purpose of this analysis was to analyze 14 types of urinary metals including mercury, uranium, tin, lead, antimony, barium, cadmium, cobalt, cesium, molybdenum, manganese, strontium, thallium, tungsten, six types of speciated arsenic, total arsenic and seven forms of polycyclic aromatic hydrocarbons (PAHs), and the link with self-reported emphysema in the US adult population.

METHODS

A cross-sectional analysis using the 2011-2012, 2013-2014 and 2015-2016 National Health and Nutrition Examination Survey datasets was conducted. A specialized weighted complex survey design analysis package was used in analyzing the data. Multivariate logistic regression models were used to assess the association between urinary metals, arsenic, and PAHs and self-reported emphysema among all participants and among non-smokers only. Models were adjusted for lifestyle and demographic factors.

RESULTS

A total of 4,181 adults were analyzed. 1-Hydroxynaphthalene, 2-hydroxynaphthalene, 3-hydroxyfluorene, 2-hydroxyfluorene, 1-hydroxypyrene, and 2 & 3-hydroxyphenanthrene were positively associated with self-reported emphysema. Positive associations were also observed in cadmium and cesium with self-reported emphysema. Among non-smokers, quantiles among 2-hydroxynaphthalene, arsenocholine, total urinary arsenic, cesium, and tin were associated with increased odds of self-reported emphysema. Quantiles among 1-hydroxyphenanthrene, cadmium, manganese, lead, antimony, thallium, and tungsten were associated with an inverse relationship with self-reported emphysema in non-smokers.

CONCLUSION

The study determined that six types of urinary PAHs, cadmium, and cesium are positively associated with self-reported emphysema. Certain quantiles of 2-hydroxynaphthalene, arsenocholine, total urinary arsenic, cesium, and tin are positively associated with self-reported emphysema among non-smokers.

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.

Passive smoking induces nasal biofilms in children

OBJECTIVES

Passive exposure of children to cigarette smoke has been implicated in several recalcitrant respiratory childhood disorders. However, to our knowledge, no information is available regarding the connection between passive exposure to tobacco smoke and the formation of nasal biofilms in children. The present study was therefore geared at investigating the hypothesis that exposure of children to household passive smoking may induce the formation of nasal biofilms.

METHODS

The study included 20 children between the ages of 6 and 12 years with a positive history of prolonged exposure to household passive smoke, and who required inferior turbinate reduction together with other procedures. Another 20 children who required similar surgeries but with negative history of exposure to household smoking formed the control group. None of children, in the study and control groups, had evidence of adenoids or infective rhinosinusitis. At the time of surgery, a tiny biopsy was taken from the lower border of the inferior turbinate. The specimens were processed for scanning and transmission electron microscopy.

RESULTS

The nasal mucosa of 11 out of 20 children with positive history of exposure to passive smoking showed biofilm formation. Ten of these biofilms grew S. aureus. On the other hand, only one child in the control group showed nasal biofilm. Longer exposure to tobacco smoke and higher urinary cotinine levels were associated with more frequent biofilm formation. Likewise, children of heavy smokers developed biofilms more frequently than other children. On the other hand, the age of the children and nasal allergy had no effect on the chances of biofilm formation.

CONCLUSIONS

This is a preliminary report showing that children exposed to household passive cigarette smoking may develop nasal biofilms. Development of these biofilms may increase susceptibility of affected children to persistent sinonasal and possibly other respiratory infections.

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.