Correlation between urinary nicotine, cotinine and self-reported smoking status among educated young adults

Assessing tobacco use in Swedish young adults from self-report and urinary cotinine: a validation study using the BAMSE birth cohort

OBJECTIVES

Studies on health effects of tobacco often rely on self-reported exposure data, which is subjective and can lead to misclassification. The aim of this study was to describe the prevalence of cigarette smoking, snus and e-cigarette use, as well as to validate self-reported tobacco use among young adults in Sweden.

METHOD

Participants of a population-based Swedish cohort (n=3052), aged 22-25 years, assessed their tobacco use in a web questionnaire. Urinary cotinine was analysed in a subsample of the study population (n=998). The agreement between self-reported tobacco use and urinary cotinine was assessed using Cohen's Kappa coefficient (κ) at a cut-off level of 50 ng/mL.

RESULTS

Patterns of tobacco use differed between men and women. Among men, 20.0% reported daily snus use, 5.8% daily cigarette smoking and 5.6% any e-cigarette use. In contrast, 3.2% of the women reported daily snus use, 9.0% daily cigarette smoking and 2.4% any e-cigarette use. Among the tobacco use categories, daily snus users had the highest levels of cotinine. Of reported non-tobacco users, 3.5% had cotinine levels above the cut-off, compared with 68.0% among both occasional cigarette smokers and snus users, 67.5% among all e-cigarette users and 94.7% and 97.8% among daily cigarette smokers and snus users, respectively. Agreement between self-reported tobacco use and urinary cotinine was classified as strong for daily use of cigarettes (κ=0.824) and snus (κ=0.861), while moderate to weak for occasional smoking (κ=0.618), occasional snus use (κ=0.573) and any e-cigarette use (κ=0.576).

CONCLUSIONS

We found high validity of self-reported tobacco use in our study population, particularly for daily tobacco use. Further, we found that daily snus users were exposed to high levels of cotinine. Together with previous findings, our results indicate good validity of self-reported tobacco use among young adults.

Association between Parental Cotinine-verified Smoking Status and Childhood Asthma: a Population-based Nationally Representative Analysis

BACKGROUND

Environmental tobacco smoke exposure due to parents is a modifiable risk factor for childhood asthma, but many studies have evaluated parental smoking using self-reported data. Therefore, we aimed to analyze the relationship between parental cotinine-verified smoking status and asthma in their children.

METHODS

This population-based cross-sectional study used data from the Korean National Health and Nutrition Examination Survey from 2014 to 2017. Participants aged 0 to 18 years with complete self-reported physician-diagnosed childhood asthma and measurement of their parental urinary cotinine levels were included. Parental urinary cotinine-verified smoking status was defined using both urinary cotinine levels and self-report, as active, passive, and non-smoker. Sample weights were applied to all statistical analyses because of a complex, multistage and clustered survey design. Logistic regression model was used to analyze the relationship between childhood asthma and parental smoking.

RESULTS

A total of 5,264 subjects aged < 19 years were included. The prevalence of asthma was 3.4%. The proportions of paternal and maternal urinary cotinine-verified active smokers during the study period were 50.4% and 16.9%, respectively. When parental urinary cotinine level increased, the proportion of parental low household income was increased (P < 0.001). There was no significant association between the parental urinary cotinine-verified smoking group and childhood asthma group. However, the adjusted odds ratios of childhood asthma in the middle and highest tertile of paternal urinary cotinine levels compared with those in lowest tertile were 1.95 (95% confidence interval [CI], 0.98-3.89) and 2.34 (95% CI, 1.21-4.54), respectively.

CONCLUSION

There seems to be a dose-related association between paternal urinary cotinine levels and the risk of childhood asthma. Because of the high rate of paternal smoking, further studies are needed to develop a targeted strategy to reduce parental smoking for childhood asthma.

Self-reported smoking status and urinary cotinine levels in patients with asthma

Objective:

To determine the frequency of active smoking among patients with asthma and individuals without asthma by self-report and urinary cotinine measurement.

Methods:

This was a cross-sectional study conducted in the city of Salvador, Brazil, and involving 1,341 individuals: 498 patients with severe asthma, 417 patients with mild-to-moderate asthma, and 426 individuals without asthma. Smoking status was determined by self-report (with the use of standardized questionnaires) and urinary cotinine measurement. The study variables were compared with the chi-square test and the Kruskal-Wallis test.

Results:

Of the sample as a whole, 55 (4.1%) reported being current smokers. Of those, 5 had severe asthma, 17 had mild-to-moderate asthma, and 33 had no asthma diagnosis. Of the 55 smokers, 32 (58.2%) were daily smokers and 23 (41.8%) were occasional smokers. Urinary cotinine levels were found to be high in self-reported nonsmokers and former smokers, especially among severe asthma patients, a finding that suggests patient nondisclosure of smoking status. Among smokers, a longer smoking history was found in patients with severe asthma when compared with those with mild-to-moderate asthma. In addition, the proportion of former smokers was higher among patients with severe asthma than among those with mild-to-moderate asthma.

Conclusions:

Former smoking is associated with severe asthma. Current smoking is observed in patients with severe asthma, and patient nondisclosure of smoking status occurs in some cases. Patients with severe asthma should be thoroughly screened for smoking, and findings should be complemented by objective testing.

Environmental and lifestyle factors affecting exposure to polycyclic aromatic hydrocarbons in the general population in a Middle Eastern area

The aim of this study was to investigate environmental and lifestyle factors affecting exposure to PAHs in the general population in a large city of the Middle East (Tehran) by measuring urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) and establishing relationships between PAHs exposure and related factors. Urine samples were collected from 222 randomly chosen subjects who were living in the urban area of Tehran, Iran. Subjects were required to complete a detailed questionnaire aimed to document their personal and sociodemographic information, activities, cooking-related appliances, smoking history/exposure, and consumed foodstuff. Identification and quantification of six OH-PAHs was carried out using a gas chromatography with mass spectrometry (GC-MS). The geometric means for 1-OHP, 1-NAP, 2-NAP, 2-FLU, 9-FLU, and 9-PHE for whole population study were 310, 1220, 3070, 530, 330, and 130 ng/g creatinine, respectively. The two naphthalene metabolites contributed on average 77% of the total concentration of six measured OH-PAHs, followed by the 2-FLU, 1-OHP, 9-FLU, and 9-PHE. The most important predictors of urinary PAHs were consumption of grilled/barbecued foods, smoking, and exposure to environmental tobacco smoking. Water pipe smoking was linked to urinary OH-PAH metabolite in a dose-response function. Residential traffic was also related with OH-PAH metabolite concentrations. Other factors including gender, age, exposure to common house insecticides, open burning, and candle burning were found to be statistically associated with the urinary levels of some OH-PAHs. High exposure to PAHs among general population in Middle Eastern large cities and its associated health implications calls for public health measures to reduce PAHs exposure.

Targeted plasma proteomics identifies a novel, robust association between cornulin and Swedish moist snuff

Lifestyle behaviors are believed to influence the body’s inflammatory state. Chronic low-grade inflammation contributes to the development of major non-communicable diseases such as diabetes, cardiovascular disease and cancer. Inflammation may thus be an important link between lifestyle and disease. We evaluated self-reported physical activity, tobacco use and alcohol consumption in relation to plasma levels of 160 validated inflammatory and cancer biomarkers. The study included 138 participants from a population-based cohort, all with repeated sampling of plasma and data ten years apart, allowing consideration of both intra- and inter-individual variation. Of 17 relationships identified, the strongest was an independent, positive association between cornulin (CRNN) and Swedish moist snuff (snus) use. We replicated the finding in a second cohort of 501 individuals, in which a dose-response relationship was also observed. Snus explained approximately one fifth of the variance in CRNN levels in both sample sets (18% and 23%). In conclusion, we identified a novel, independent, dose-dependent association between CRNN and snus use. Further study is warranted, to evaluate the performance of CRNN as a potential snus biomarker. The putative importance of lifestyle behaviors on a wide range of protein biomarkers illustrates the need for more personalized biomarker cut-offs.

Obese But Fit: The Relationship of Fitness to Metabolically Healthy But Obese Status among Sexual Minority Women

PURPOSE

The purpose of this study was to describe fitness characteristics of metabolically healthy sexual minority women who are obese.

METHODS

As part of the Healthy Weight in Lesbian and Bisexual Women Initiative funded by the U.S. Office on Women's Health, one site enrolled self-identified lesbian or bisexual women age 40 and older in a randomized controlled trial that evaluated interventions to improve health. Women with waist-to-height ratio of 0.5 or greater were classified as obese. Women without diabetes or cardiovascular disease and with normal range fasting blood level measurements of glucose, triglycerides, high-density cholesterol, and blood pressure were classified as metabolically healthy but obese (MHO). Otherwise, women were classified as metabolically unhealthy obese (MUHO). Fitness measurements included predicted VO2 maximum, 1-minute heart rate recovery, and strength (single maximal leg lift and chest press). Self-reported demographic and physical activity level data were obtained by standardized questionnaires.

RESULTS

Of the 53 participants who completed the eligibility screener in Columbia, Missouri, 47 were enrolled in the study (89% participation proportion) with 45 categorized as obese. Approximately one-third (38%) were MHO. The majority of MHO and MUHO participants ranked poor or very poor on a composite fitness score that included measures of strength, flexibility, and aerobic fitness (75.0% and 77.8%, respectively). In the logistic regression models, better 1-minute heart rate recovery after peak exercise performance was significantly associated with MHO individuals (odds ratio, 2.92; 95% CI, 1.13-9.10) compared with MUHO. No other fitness measure was significantly different between the two groups.

CONCLUSION

Consistent with other studies, we identified more than one-third of our obese sexual minority women as MHO. Fitness measures may be potential predictors of MHO status because one measure, heart rate recovery, was significantly associated with MHO status. With the population prevalence of obesity high and even higher among lesbian or bisexual women, sexual minority women are an ideal population for a longitudinal study to better understand MHO characteristics.

Biomonitoring of tobacco smoke exposure and self-reported smoking status among general population of Tehran, Iran

The present study aimed to find a correlation between the self-reported smoking status of the residents of Tehran, Iran, and the urine cotinine as a biomarker of exposure to tobacco smoke. The self-reported data was collected from 222 participants who were living in the urban area of Tehran. The urine samples of participants were collected for cotinine analysis. Urine cotinine was measured by an enzymatic immunoassay technique. Tobacco smoking was reported by 76 (34.23 %) participants as the self-reported data, and the number of males in this report was higher than of females (p < 0.001). By adding the number of the self-reported non-smokers with cotinine levels above the cutoff value of >100 ng/ml to self-reported smokers, the smoking prevalence increased from 34.23 % (95 % CI 28.01-40.88 %) to 36.48 % (95 % CI 30.14-43.19 %). Using the cutoff value, sensitivity and specificity of the self-reported smoking status were respectively 90.12 % (95 % CI 81.46-95.64 %) and 98 % (95 % CI 93.91-99.55 %). The levels of agreement between self-reported tobacco smoking and urinary cotinine concentrations was 95.1 % (k = 0.89, p < 0.001, 95 % CI = 0.81-0.95). Based on the results, self-reported smoking can be a valid marker for assessing the tobacco exposure, and it can be of use in large epidemiological studies.

Comparison of SemiQuantitative Cotinine Values Obtained by the DRI Immunoassay and Values Obtained by a Liquid Chromatography-Tandem Mass Spectrometry-Based Method: The DRI Immunoassay is Suitable for Screening Purposes Only Because Semiquantitative Values May Be Unreliable

BACKGROUND

DRI cotinine assay is suitable only for screening for cotinine in urine specimens. We studied the reliability of DRI cotinine semiquantitative values by comparing them with the cotinine concentration obtained with a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.

METHODS

Semiquantitative cotinine concentrations in 39 urine specimens obtained by the DRI immunoassay were compared with cotinine concentrations obtained by LC-MS/MS.

RESULTS

The DRI cotinine assay consistently overestimated cotinine values obtained by the LC/MS/MS method (y = 1.1529 x + 252.24, n = 39, R² = 0.8899) indicating that semiquantitative values obtained using the DRI assay may be unreliable. However, no false-negative results were observed using the DRI assay.

CONCLUSION

DRI cotinine assay is suitable only for screening cotinine in urine specimens.

Pitfalls in the assessment of smoking status detected in a cohort of South African RA patients

This study was conceived in an attempt to explain the unexpectedly high frequency of elevated levels of serum cotinine measured retrospectively in a cohort of predominantly black South African females with rheumatoid arthritis (RA), findings that were inconsistent with the smoking histories derived from health questionnaires. The discrepant findings suggested either a greater tendency towards underreporting of smoking status in the study cohort, or possible confounding effects of the use of smokeless tobacco products. In addition to the cohort of RA patients (n = 138, of whom 115 (83 %) were female), blood samples were also taken from a second cohort consisting of 29 declared smokers, 18 (62 %) of whom where females, 29 smokeless tobacco (SLT) users (all female), and 22 non-users of any tobacco products, 18 (82 %) of whom were females. Serum cotinine levels were determined using an ELISA procedure. Cotinine levels of >10.0 ng/ml were detected in serum specimens from 43 (31 %), RA patients of whom 35 (81 %) were female, with a median value of 50.1 ng/ml and interquartile range (iqr) of 68.6. Only 18 of the 35 females indicated that they smoked. The groups of declared smokers and SLT users had equivalent median serum cotinine levels of 88.0 ng/ml (iqr = 10.8 ng/ml) and 87.0 ng/ml (iqr = 15.6 ng/ml), respectively, while cotinine was undetectable in specimens from non-tobacco product users (<0.2 ng/ml). Users of SLT products in South Africa are predominantly female and have serum cotinine levels which are comparable with those of current smokers, raising concerns about the validity of measurement of cotinine as the sole objective marker of smoking status in populations with high usage of SLTs. This situation can be rectified by ensuring that usage of SLT products is accurately recorded in health questionnaires, while inclusion of measurement of one or more additional, objective biomarkers of smoking in combination with cotinine may enable reliable distinction between smoking and usage of SLTs which, given the associated risks, is a strategy of particular relevance in RA.

Determinants of active and environmental exposure to tobacco smoke and upper reference value of urinary cotinine in not exposed individuals

The aims of this study were (1) to explore the behavioral and sociodemographic factors influencing urinary cotinine (COT-U) levels in active smokers and in environmental tobacco smoke (ETS)-exposed individuals, (2) to assess the specificity and sensitivity of the questionnaire for identifying active smokers and nonsmokers, and (3) to derive the upper reference value of COT-U in non-ETS exposed individuals. The COT-U levels of 495 adults (age range 18-69 years) who classified themselves as active smokers (29%) or as nonsmokers with (17%) or without (83%) ETS exposure were quantified by LC-MS-MS (quantification limit: 0.1µg/L, range of linearity: 0.1-4000µg/L). Median COT-U levels in these groups were 883, 1.38, and 0.39µg/L, respectively. Significant determinants of COT-U levels in active smokers were the number of cigarettes per day, type of smoking product, smoking environment, as well as time between the last cigarette and urine collection. Among ETS-exposed nonsmokers, significant determinants were living with smokers, being exposed to smoke at home, ETS exposure duration, as well as time between the last exposure and urine collection. When a 30-µg/L COT-U cut-off value was used to identify active daily smoking, the sensitivity and specificity of the questionnaire were 94% and 98%, respectively. For ETS exposure, the COT-U value of 1.78 (0.90 confidence interval 1.75-1.78) µg/L, corresponding to the 95th percentiles of the COT-U distribution in non-ETS-exposed participants, is proposed as upper reference value to identify environmental exposure.

Urinary cotinine levels and environmental tobacco smoke in mothers and children of Romania, Portugal and Poland within the European human biomonitoring pilot study

The aim of this study was to explore data from the DEMOCOPHES study population for Romania, Portugal and Poland, in order to assess smoking patterns and the extent of ETS exposure and compare the national study samples with reference to the respective anti-smoking laws. The subset of the DEMOCOPHES study sample consisted of 360 children and their mothers (120 in each of the three countries - Romania (RO), Portugal (PT) and Poland (PL). Smoking was assessed using a detailed questionnaire for the participants, which addresses both active and passive smoking. This assessment uses exposure-relevant questionnaire data, in particular on the home environment and residence, socio-demographic characteristics, lifestyle such as nutrition, smoking behavior, other exposure-relevant behavior and occupational history, as well as urinary cotinine and creatinine measurements. We performed general statistical analysis and innovative receiver operating characteristic (ROC) curve analyses. Smoking prevalence as evaluated by the questionnaire was generally high, and higher than official statistics, which suggests some under-reporting in the countries, particularly in Romania. Urinary cotinine levels provided biochemical confirmation of the high and similar smoking prevalence for the three countries. Concerning ETS exposure, Romania presented significantly higher levels, for children as well as for non-smoking mothers, with Portugal showing significantly lower levels. Compared to non-smoking mothers, the children showed relatively higher ETS exposure levels in all three countries. The established country-specific optimal cut-off values in urinary cotinine to distinguish smokers from non-smokers vary more than those to discriminate ETS exposure extent in non-smoking mothers and children. Although different between countries, these values are a valuable output to monitor effectiveness of both national antismoking laws and educational programs in the three countries. The findings of this study point to the urgent need for stronger, more effective and well enforced smoke-free legislation in the three countries.

Zinc Sulfate, a Recently Introduced Urinary Adulterant Can Invalidate Urine Cotinine Test Using Immunoassay but Has Less Effect on Liquid Chromatography Combined With Tandem Mass Spectrometry-Based Test

OBJECTIVE

Zinc sulfate is a recently introduced urinary adulterant, which causes false-negative results with immunoassays used for screening drugs of abuse in urine but whether zinc sulfate also could invalidate urine cotinine assay using immunoassay or liquid chromatography combined with mass spectrometry has never been studied.

DESIGN AND METHOD

Four urine pools containing none detected to high levels of cotinine were analyzed using DRI cotinine immunoassay on the Olympus 640 analyzer as well as using liquid chromatography combined with tandem mass spectrometry. Specimens were reanalyzed after supplementing with various amounts of zinc sulfate that are known to invalidate immunoassays used for drugs of abuse testing.

RESULTS

Zinc sulfate in all concentrations studied caused false-negative results using immunoassays, but zinc sulfate also reduced cotinine values by approximately 2.1%-38.4% when analyzed using liquid chromatography combined with mass spectrometry.

CONCLUSIONS

Zinc sulfate caused false-negative cotinine result when DRI immunoassay was used and also had small to moderate impact on liquid chromatography combined with tandem mass spectrometry-based assay for urine cotinine.

Does South Korea have hidden female smokers: discrepancies in smoking rates between self-reports and urinary cotinine level

BACKGROUND

Female smoking is perceived very negatively in East Asian countries such as South Korea, Japan, and China, as well as in Islamic countries. These countries' self-reported surveys (SRs) tend to produce results that underestimate the number of smokers, owing to the social desirability response bias. The present study seeks to assess South Korea, Europe, and the Americas, by comparing data from SRs with those from urinary cotinine samples.

METHODS

Current smoking rates were calculated using the SRs and the urinary cotinine concentration (UCC) methods according to socioeconomic factors. In order to examine response accuracy regarding current smoking status in the SRs, participants who both completed the SRs and acquired UCC results were subject to analyses of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and difference ratio (DR) with respect to gender, age, region, economic level, household status, and the presence of chronic disease.

RESULTS

Based on self-reports, the current smoking rate among women was 7.1% (official smoking rates), while that according to the UCC was 18.2%; the rates for men were 47.8% and 55.1%, respectively. The sensitivity of males was 0.8553, the specificity 0.9768, PPV 0.9783, NPV 0.8465, and the difference ratio (DR) was 1.143. The sensitivity for females was 0.3670, the specificity 0.9956, PPV 0.9486, NPV 0.8761, and the DR was 2.6. These results exhibit a very low response alignment rate compared to males.

CONCLUSION

This study shows that the actual female smoking rate is significantly higher than that reported officially, but also that the gap is decreasing steadily. Females exhibited a higher rate of false responses, which resulted in an underestimation of the female smoking rate.

Prevalence and validity of self-reported smoking in Indigenous and non-Indigenous young adults in the Australian Northern Territory

Background

In this study, we used data from Australia’s Northern Territory to assess differences in self-reported smoking prevalence between the Indigenous and non-Indigenous populations. We also used urinary cotinine data to assess the validity of using self-reported smoking data in these populations.

Methods

The Aboriginal Birth Cohort (ABC) is a prospective study of 686 Aboriginal babies born in Darwin 1987–90. The Top End Cohort (TEC) is a study of non-Indigenous adolescents, all born in Darwin 1987–91. In both studies, participants aged between 16 and 21 years, were asked whether they smoked. Urinary cotinine measurements were made from samples taken at the same visits.

Results

Self-reported smoking prevalence was 68% in the ABC and 14% in the TEC. Among the self-reported non-smokers, the median cotinine levels were higher in the ABC (33 ng/ml) than in the TEC (5 ng/ml), with greater percentages of reported non-smokers in the under 50 ng/ml group in the TEC than in the ABC

Conclusions

Prevalence of smoking was much higher in the ABC than in the TEC. The higher cotinine levels in ABC non-smokers may reflect an underestimated prevalence, but is also likely to reflect higher levels of passive smoking. A broader approach encompassing social, cultural and language factors with increased attention to smoking socialisation factors is required.

The Prevalence of Self-Reported Smoking and Validation with Urinary Cotinine Among Commercial Drivers in Major Parks in Lagos, Nigeria

The validity of self-reported smoking is questionable because smokers are inclined to deny smoking. We aimed to determine the prevalence of self-reported smoking among intra-city commercial drivers in Lagos, and assess its validity based on urinary cotinine assessment. This study was conducted at three major motor parks in Lagos, Nigeria. Information on smoking status and habits was obtained from 500 consecutive male drivers using a structured questionnaire during a face-to-face interview. Eighty-one self-reported smokers and non-smokers were selected by systematic random sampling for urinary cotinine assessment using cotinine strips. The prevalence of self-reported smoking was compared to the prevalence of smoking based on urinary cotinine and the specificity and positive predictive values of self-reported smoking was determined. Prevalence of self-reported current smoking was 32% and 17.9% of non-smokers were passive smokers. Among 81 drivers in whom urinary cotinine assessment was performed, the prevalence of smoking based on self-report was 34 (42%) compared to 41 (50.6%) when based on urinary cotinine, (X²=38.56, P<0.001). The rate of misclassification among self-reported non-smokers as smokers was 21.3% and misclassification rate for self-reported smokers as non-smokers was 8.8%. The sensitivity of self-reported smoking in accurately classifying smoking status was 91.2% and the specificity was 78.7%. The prevalence of self-reported cigarette smoking among commercial drivers in Lagos is high and a significant proportion of self-reported non-smokers are passive smokers. Self-reported smoking status obtained during face-to-face interview appears unreliable in obtaining accurate smoking data in our locality.

Secondhand smoke exposure and urine cotinine concentrations by occupation among Korean workers: results from the 2008 Korea National Survey for Environmental Pollutants in the Human Body

This study aimed to estimate the status of secondhand smoke (SHS) exposure through urine cotinine analysis among nonsmoking workers in Korea and to analyze factors affecting urine cotinine concentrations. Data were based on "The 2008 Korea National Survey for Environmental Pollutants in the Human Body," a cross-sectional study of the National Institute of Environmental Research of Korea. We selected 1448 nonsmoking adult workers from 200 localities to participate in this survey. Urine cotinine concentrations were analyzed using a gas chromatograph-mass selective detector. We calculated separate covariate-adjusted geometric means for socio-demographic variables for males, females, and total subjects by analysis of covariance (ANCOVA). Statistical analyses were performed using SPSS version 18.0 (SPSS Inc., Chicago, Ill.). The prevalence of self-reported exposure to SHS was 36.9%. The geometric mean (95% confidence interval) of urine cotinine concentrations among all participants was 16.50 (14.48-18.80) μg/L. Gender, living area, education, and SHS exposure showed significant differences in urine cotinine concentrations. The urine cotinine concentrations of farmworkers and blue-collar workers such as skilled agricultural, forestry, and fishery workers, and elementary occupations were higher than those of white-collar workers such as clerical support workers, technicians, and associate professionals. Such a high proportion of the population having high urine cotinine levels indicates widespread exposure to SHS among nonsmoking workers in Korea. Furthermore, the urine cotinine levels among nonsmoking workers exposed to SHS varied by occupation. The measured urine cotinine concentration is suggested to be a valuable indication of SHS exposure in Korea.

Simultaneous measurement of urinary total nicotine and cotinine as biomarkers of active and passive smoking among Japanese individuals

OBJECTIVES

Measuring urinary cotinine is a popular and established method of biologically monitoring exposure to tobacco smoke. However, the lower detection limit of cotinine often impedes the evaluation of passive (second-hand) smoking and this, together with unconverted nicotine, does not reflect actual levels of exposure. Furthermore, a portion of the Japanese population might have decreased ability to metabolize nicotine. The present study was therefore carried out to validate the simultaneous analysis of total concentrations of free nicotine and cotinine and their glucuronides to determine actual levels of voluntary and involuntary exposure to cigarette smoke.

METHODS

Urine samples from 118 Japanese smokers and 117 non-smokers were analyzed using gas chromatography-mass spectrometry. Voluntary and involuntary smoking status was self-reported and workplace smoking restrictions were objectively evaluated.

RESULTS

The integrated sum of all concentrations showed 2.2- and 2.4-fold higher total levels (free and glucuronide) of nicotine and cotinine relative to the free levels. Median (quartiles) of total nicotine and cotinine were 1635 (2222) and 3948 (3512) ng/mL in smokers, and 3.5 (5.3) and 2.8 (4.2) ng/mL in non-smokers. Concentrations of urinary nicotine were higher than those of cotinine in 21 % of smokers and in 54 % of non-smokers. Nicotine and cotinine levels were significantly associated with a smoking habit, as well as being significantly associated with the workplace and home environments of non-smokers.

CONCLUSIONS

The present method can monitor voluntary and involuntary exposure to tobacco smoke. Measuring total urinary nicotine levels might be useful for analyzing exposure to cigarette smoke among non-smokers.

Self-reported tobacco smoke exposure and plasma cotinine levels during pregnancy--a validation study in Northern Japan

Maternal smoking is a critical public health concern requiring the establishment of its prevalence rate and clinical impact. Maternal self-reported information of tobacco smoke exposure requires validation using accurate biochemical analysis. This study examined the association between self-reported exposure to tobacco smoke and plasma cotinine level in Japanese pregnant women. We collected information about smoking and secondhand smoke (SHS) exposure during pregnancy from 5128 pregnant women in a prospective cohort design, and analyzed biochemically maternal blood samples using the enzyme-linked immunosorbent assay (ELISA) technique. Based on self-reports, the subjects were classified into three groups: 650 smokers, 728 ex-smokers and 3750 non-smokers. Using the receiver operating characteristic (ROC) curve, plasma cotinine cut-off value of 11.48 ng/mL was established for separating smokers from non-smokers, resulting in a smoking prevalence of 14%. A cotinine cut-off value of 0.21 ng/mL for discriminating exposed and unexposed nonsmokers resulted in a 63% prevalence of exposure to tobacco smoke among nonsmokers. Cotinine biomarker analysis proved accurate in validating self-reported smoking information in the subjects. Lower validity of SHS exposure suggests a need to confirm questionnaire information with biochemical analysis.

A survey of schoolchildren's exposure to secondhand smoke in Malaysia

BACKGROUND

There is a lack of data describing the exposure of Malaysian schoolchildren to Secondhand Smoke (SHS). The aim of this study is to identify factors influencing schoolchildren's exposures to SHS in Malaysia.

METHOD

This cross-sectional study was carried out to measure salivary cotinine concentrations among 1064 schoolchildren (10-11 years) attending 24 schools in Malaysia following recent partial smoke-free restrictions. Parents completed questionnaires and schoolchildren provided saliva samples for cotinine assay.

RESULTS

The geometric mean (GM) salivary cotinine concentrations for 947 non-smoking schoolchildren stratified by household residents' smoking behaviour were: for children living with non-smoking parents 0.32 ng/ml (95% CI 0.28-0.37) (n = 446); for children living with a smoker father 0.65 ng/ml (95% CI 0.57-0.72) (n = 432); for children living with two smoking parents 1.12 ng/ml (95% CI 0.29-4.40) (n = 3); for children who live with an extended family member who smokes 0.62 ng/ml (95% CI 0.42-0.89) (n = 33) and for children living with two smokers (father and extended family member) 0.71 ng/ml (95% CI 0.40-0.97) (n = 44). Parental-reported SHS exposures showed poor agreement with children's self-reported SHS exposures. Multiple linear regression demonstrated that cotinine levels were positively associated with living with one or more smokers, urban residence, occupation of father (Armed forces), parental-reported exposure to SHS and education of the father (Diploma/Technical certificate).

CONCLUSIONS

This is the first study to characterise exposures to SHS using salivary cotinine concentrations among schoolchildren in Malaysia and also the first study documenting SHS exposure using salivary cotinine as a biomarker in a South-East Asian population of schoolchildren. Compared to other populations of similarly aged schoolchildren, Malaysian children have higher salivary cotinine concentrations. The partial nature of smoke-free restrictions in Malaysia is likely to contribute to these findings. Enforcement of existing legislation to reduce exposure in public place settings and interventions to reduce exposure at home, especially to implement effective home smoking restriction practices are required.

Relative performance of common biochemical indicators in detecting cigarette smoking

AIMS

Many cities have banned indoor smoking in public places. Thus, an updated recommendation for a breath carbon monoxide (CO) cut-off is needed that optimally determines smoking status. We evaluated and compared the performance of breath CO and semiquantitative cotinine immunoassay test strips (urine and saliva NicAlert®) alone and in combination.

DESIGN

Cross-sectional study.

SETTING

Urban drug addiction research and treatment facility.

PARTICIPANTS

Ninety non-treatment-seeking smokers and 82 non-smokers.

MEASUREMENTS

Participants completed smoking histories and provided breath CO, urine and saliva specimens. Urine and saliva specimens were assayed for cotinine by NicAlert® and liquid chromatography-tandem mass spectrometry (LCMSMS).

FINDINGS

An optimal breath CO cut-off was established using self-report and LCMSMS analysis of cotinine, an objective indicator, as reference measures. Performance of smoking indicators and combinations were compared to the reference measures. Breath CO ≥5 parts per million (p.p.m.) optimally discriminated smokers from non-smokers. Saliva NicAlert® performance was less effective than the other indicators.

CONCLUSIONS

In surveys of smokers and non-smokers in areas with strong smoke-free laws, the breath carbon monoxide cut-off that discriminates most effectively appears to be ≥5 p.p.m. rather than the ≥10 p.p.m. cut-off often used. These findings may not generalize to clinical trials, regions with different carbon monoxide pollution levels or areas with less stringent smoke-free laws.

Assessment of nicotine dependence among adolescent and young adult smokers: a comparison of measures

INTRODUCTION

Tobacco use often starts in adolescence, yet assessment of dependence among adolescent smokers remains a challenge, particularly given the potential discord between self-reports of smoking behavior and actual use. We could find no prior study, among adolescents, that directly compares the association between objective biomarkers of tobacco exposure (e.g., cotinine) and multiple measures of dependence. This study examined the concurrent validity of two common dependence measures: the Fagerström Test for Nicotine Dependence (FTND) and the Hooked on Nicotine Checklist (HONC). We further examined the FTND by removing the one item on cigarettes smoked per day.

METHODS

Based within a parent clinical trial for adolescent smoking cessation, eligible participants were 12-21years old, smoking >/=5cigarettes per day on average, and with urine cotinine >100ng/ml at baseline. Results are based on participants who completed each measure and who provided a urine cotinine sample at baseline (N=73).

RESULTS

Results showed that the FTND was associated with cotinine (p<0.001; R(2)=0.25), and that this relationship held true for the revised FTND as well (p<0.001; R(2)=0.18). However, the HONC was only marginally associated with cotinine (p=0.06; R(2)=0.09).

DISCUSSION

Our results suggest that the FTND may be better associated with actual smoking behavior in adolescents as compared to the HONC. Pending replication, our data provide caution with regard to assessment of nicotine dependence at least among established adolescent smokers who have more entrenched smoking behavior.

Tobacco smoking in seven Latin American cities: the CARMELA study

Objective

This study aimed to explore tobacco smoking in seven major cities of Latin America.

Methods

The Cardiovascular Risk Factor Multiple Evaluation in Latin America (CARMELA) study is a cross-sectional epidemiological study of 11 550 adults between 25 and 64 years old in Barquisimeto, Venezuela; Bogota, Colombia; Buenos Aires, Argentina; Lima, Peru; Mexico City, Mexico; Quito, Ecuador; and Santiago, Chile. Tobacco smoking, including cigarettes, cigars and pipes, was surveyed among other cardiovascular risk factors.

Results

Santiago and Buenos Aires had the highest smoking prevalence (45.4% and 38.6%, respectively); male and female rates were similar. In other cities, men smoked more than women, most markedly in Quito (49.4% of men vs 10.5% of women). Peak male smoking prevalence occurred among the youngest two age groups (25–34 and 35–44 years old). Men and women of Buenos Aires smoked the highest number of cigarettes per day on average (15.7 and 12.4, respectively). Men initiated regular smoking earlier than women in each city (ranges 13.7–20.0 years vs 14.2–21.1 years, respectively). Exposure to secondhand tobacco smoke at workplace for more than 5 h per day was higher in Barquisimeto (28.7%), Buenos Aires (26.8%) and Santiago (21.5%). The highest prevalence of former smokers was found among men in Buenos Aires, Santiago and Lima (30.0%, 26.8% and 26.0% respectively).

Conclusions

Smoking prevalence was high in the seven CARMELA cities, although patterns of smoking varied among cities. A major health and economic burden is inevitable in urban Latin America unless effective comprehensive tobacco control measures recommended by the World Health Organisation Framework Convention on Tobacco Control are implemented.