Discrepancy between Self-Reported and Urine-Cotinine Verified Smoking Status among Korean Male Adults: Analysis of Health Check-Up Data from a Single Private Hospital

Association between job satisfaction and current smoking and change in smoking behavior: a 16-year longitudinal study in South Korea

BACKGROUND AND AIMS

Previous studies have found that job satisfaction is closely associated with various health outcomes of workers. Our study measured the association between job satisfaction and current smoking and change in smoking behavior.

DESIGN

Data from the longitudinal Korea Labor and Income Panel Study (KLIPS) that consist of nationally representative samples were used. The repeated measures analysis was conducted.

SETTING

South Korea, 2005-2021.

PARTICIPANTS

In total, 21 154 workers in Korea followed from 2005 to 2021 (145 120 observations) were included as study participants.

MEASUREMENTS

The main predictor variable, job satisfaction, was assessed using a five-item general job satisfaction questionnaire. Job satisfaction was classified into 'dissatisfied', 'neutral' and 'satisfied', according to the tertiles of the sum of scores. The outcomes of interest were current smoking and initiation and cessation of smoking in the subsequent year.

FINDINGS

Compared with those with a neutral level of job satisfaction, those who reported dissatisfaction with their job had an increased risk of smoking initiation [odds ratio (OR) = 1.11, 95% confidence interval (CI) = 1.01-1.22)]. Workers satisfied with their jobs were associated with a decreased likelihood of current smoking (OR = 0.96, 95% CI = 0.94-0.98) and smoking initiation (OR = 0.90, 95% CI = 0.81-0.99). There was a positive relationship between cumulative years of job dissatisfaction and smoking risk: > 4 years of experiencing job dissatisfaction was positively related to current smoking (OR = 1.14, 95% CI = 1.06-1.24) and smoking initiation (OR = 1.22, 95% CI = 1.00-1.49) and negatively related to smoking cessation (OR = 0.84, 95% CI = 0.72-0.99).

CONCLUSIONS

In Korea, job dissatisfaction appears to be associated with an increased risk of smoking initiation.

Evaluating the impact of varying expired carbon monoxide thresholds on smoking relapse identification: insights from the E3 trial on e-cigarette efficacy for smoking cessation

OBJECTIVES

Expired carbon monoxide (ECO) is often used in smoking cessation trials to biochemically validate self-reported smoking status. The optimal ECO threshold to distinguish individuals who smoke from those who do not is debated.

DESIGN

The data from the 'Evaluating the Efficacy of E-Cigarette use for Smoking Cessation (E3) Trial' were used; the E3 trial was a randomised controlled trial that examined e-cigarettes efficacy for smoking cessation.

SETTINGS

Participants were recruited from 17 Canadian sites across 4 provinces.

PARTICIPANTS

This substudy included data from participants who returned for at least one of the clinical visits at week 4 (291), 12 (257) or 24 (218) and provided both self-reported smoking status and ECO measures. Analyses were based on 766 paired measures (ie, self-reported smoking status with corresponding ECO).

RESULTS

The ability of ECO measurements to discriminate between adults who reported smoking and those who reported abstinence varied with the threshold used. ECO thresholds of 6, 7, 8 and 9 parts per million (ppm) yielded the greatest area under the receiver operating characteristic curve (0.84). These thresholds produced sensitivities of 84%, 82%, 78% and 76% and specificities of 84%, 87%, 90% and 91%, respectively. However, at a threshold of 6 ppm, intersecting sensitivity (84%) and specificity (84%) were maximised with respect to each other. Biochemical validation had the highest agreement with self-report at an ECO threshold of 6 ppm (κ=0.57; 95% CI, 0.51 to 0.64).

CONCLUSION

The classification of participants' smoking status depends on the ECO threshold used for biochemical validation. We recommend that future smoking cessation trial investigators analyse and report the impact that varying ECO thresholds has on trial results.

TRIAL REGISTRATION NUMBER

NCT02417467.

Effect of lifestyle modification on hepatocellular carcinoma incidence and mortality among patients with chronic hepatitis B

BACKGROUND

Research exploring the influence of healthier lifestyle modification (LSM) on the risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB) is limited.

AIM

To emulate a target trial to determine the effect of LSM on HCC incidence and mortality among patients with CHB by large-scale population-based observational data.

METHODS

Among the patients with CHB enrolled in the Korean National Health Insurance Service between January 1, 2009, and December 31, 2017, those aged ≥ 20 years who drank alcohol, smoked cigarettes, and were sedentary were analyzed. Exposure included at least one LSM, including alcohol abstinence, smoking cessation, and regular exercise. The primary outcome was HCC development, and the secondary outcome was liver-related mortality. We used 2:1 propensity score matching to account for covariates.

RESULTS

With 48766 patients in the LSM group and 103560 in the control group, the adjusted hazard ratio (HR) for incident HCC and liver-related mortality was 0.92 [95% confidence interval (CI): 0.87-0.96] and 0.92 (95%CI: 0.86-0.99) in the LSM group, respectively, compared with the control group. Among the LSM group, the adjusted HR (95%CI) for incident HCC was 0.84 (0.76-0.94), 0.87 (0.81-0.94), and 1.08 (1.00-1.16) for alcohol abstinence, smoking cessation, and regular exercise, respectively. The adjusted HR (95%CI) for liver-related mortality was 0.92 (0.80-1.06), 0.81 (0.72-0.91), and 1.15 (1.04-1.27) for alcohol abstinence, smoking cessation, and regular exercise, respectively.

CONCLUSION

LSM lowered the risk of HCC and mortality in patients with CHB. Thus, active LSM, particularly alcohol abstinence and smoking cessation, should be encouraged in patients with CHB.

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.

Secondhand tobacco smoke exposure among children under 5 years old: questionnaires versus cotinine biomarkers: a cohort study

OBJECTIVES

Cotinine is the gold standard to estimate prevalence of secondhand tobacco smoke (SHS) exposure, and assay limit of detection (LOD) cut-points are typically used regardless of age. Our aim was to compare the concordance between mother-reported SHS exposure and serum cotinine categorising children as exposed with the assay LOD or age-specific cut-points.

DESIGN

Data from the Health Outcomes and Measures of the Environment (HOME) Study, a prospective pregnancy and birth cohort.

SETTING

Hospital or participants' homes.

PARTICIPANTS

389 pregnant women aged 18 years and older, between 13 and 19 weeks of gestation, living in a five-county region of the Cincinnati, Ohio metropolitan area, and with follow-up on their children at birth and ages 12, 24, 36 and 48 months.

PRIMARY AND SECONDARY OUTCOME MEASURES

Children's serum cotinine, mother-reported active smoking and SHS exposure were available at birth and during follow-up visits. We used Cohen's kappa index to assess concordance between maternal self-report and child's serum cotinine concentrations. We estimated optimal age-specific cut-points, their sensitivity-specificity and positive-negative predictive values with receiver operating characteristic curves.

RESULTS

Self-reported exposure and cotinine data were available for 280 women who gave birth to singleton child. When applying the assay LOD (0.015 ng/mL), concordance between maternal report and serum cotinine, without accounting for age, was below 0.23 at all times. When using age-specific cut-points (12 months: 0.11 ng/mL; 24 months: 0.08 ng/mL; 36 months: 0.05 ng/mL and 48 months: 0.04 ng/mL), concordance improved, being low at 12 months (0.39), moderate at 24 and 36 months (0.47 and 0.43) and high at 48 months (0.62).

CONCLUSIONS

Concordance between mother-reported SHS exposure among children under 5 years and serum cotinine improved considerably after applying the cohort-specific and age-specific cut-points. Future studies are necessary to verify these results.

Validity assessment of self-reported smoking status in firefighters using the urine cotinine test

BACKGROUND

In firefighters, smoking management is important because they are exposed to various harmful substances in their occupational environment. Accurate surveys of smoking status are essential to control tobacco use. The main disadvantage of self-report questionnaires, which are commonly used for investigating smoking status, is the possibility that the subjects' response are invalid. If the validity of firefighters' answers on smoking questionnaires is not adequate, different methods will be needed for investigating smoking status in firefighters.

METHODS

This study was conducted on 445 male firefighters from 9 fire stations in Daegu (the city in South Korea) who visited a medical institution for medical checkup in 2016. The urine cotinine test strip (DCT-102; CLIAwaived Inc., cut-off value = 200 ng/mL) was used to classify the actual smoking status and to assess the validity of self-reported smoking status on questionnaires. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the smoking questionnaires were analyzed. Subjects testing positive in the urine cotinine test (assumed the actual current smokers) were selected. The frequency at which actual current smokers were misclassified as current non-smokers by the questionnaire was calculated. Subjects' characteristics were analyzed for possible association with any discrepancy between self-reported smoking status and urine cotinine test results.

RESULTS

The smoking rates among firefighters surveyed using the smoking questionnaire and the urine cotinine test were 22.47% and 51.24%, respectively. Of the all subjects, 29.66% (n = 132) were misclassified. The sensitivity of the smoking questionnaire was 42.98%, the specificity was 99.08%, the PPV was 98.00%, and the NPV was 62.32%. In the 228 subjects classified as current actual smokers by the urine cotinine test, 57.02% (n = 130) were misclassified on the questionnaire. The misclassification rate increased with age. The degree of misclassification also increased when subjects had a history of disease.

CONCLUSIONS

In present study, the validity of the smoking questionnaire for firefighters was not suitable for investigating smoking status due to low sensitivity. To increase the validity of smoking status monitoring in firefighters, consideration of the various factors like survey environment, subjects' characteristics, and occupational factors is needed.

Impact of nicotine replacement therapy as an adjunct to anti-tuberculosis treatment and behaviour change counselling in newly diagnosed pulmonary tuberculosis patients: an open-label, randomised controlled trial

We evaluated the impact of intensive smoking cessation activities as an adjunct to anti-tuberculosis treatment on patient-related treatment outcomes. In this open-label, randomised controlled trial, self-reporting smokers with pulmonary tuberculosis who initiated standard anti-tuberculosis treatment were randomised to either nicotine replacement therapy and behaviour change counselling (n = 400) or counselling alone (n = 400) provided at baseline and two follow-up visits. The primary outcomes were change in TBscore at 24-weeks and culture conversion at 8-weeks. Biochemical smoking quit rates defined as serum cotinine levels <10 ng/mL and/or exhaled carbon monoxide levels <6 ppm (47·8% vs 32·4%, p-value =< 0·001) and self-reported quit rates (69.3% vs 38·7%, p-value =< 0·001) were significantly higher in the intervention arm at 24-weeks. Though the TBscores at 24 weeks (95% CI) were lower in the intervention arm [2·07 (1·98, 2·17) versus 2.12 (2·02, 2·21)], the difference was not clinically meaningful. Patients in the control arm required treatment extension more often than intervention arm (6·4% vs 2·6%, p-value = 0·02). Combining nicotine replacement therapy with behaviour change counselling resulted in significantly higher quit rates and lower cotinine levels, however, impact on patient-related (TBscore) or microbiological outcomes (culture conversion) were not seen.

Relation between secondhand smoke exposure and cardiovascular risk factors in never smokers

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Objective:

Secondhand smoke exposure (SHSE) in nonsmokers has been associated with premature cardiovascular mortality and ischemic heart disease. We conducted a cross-sectional, population-based study evaluating the relationship between SHSE, measured by subjective and objective methods, and conventional cardiovascular risks such as blood pressure, lipid profiles, and fasting glucose.

Methods:

We extracted information on 7376 healthy adults who had never smoked, for whom there were available urine cotinine levels, from the Korea National Health and Nutrition Examination Survey 2008–2011. SHSE was defined using self-report questionnaires and urine cotinine levels. The main outcomes included SBP and DBP, serum lipid profiles, and fasting glucose.

Results:

The mean age of the study population was 45.4 ± 0.4 years and 75.2% were women. Self-reported SHSE had no significant association with study outcomes except for DBP, which had marginally positive relationships (P = 0.060). Unadjusted analysis showed higher cotinine levels were associated with lower SBP, total cholesterol, LDL cholesterol, and triglyceride. All associations lost statistical significance after multivariable adjustment. Fasting glucose had a positive relationship with urine cotinine in quartiles but not with logarithm-transformed cotinine.

Conclusion:

Although SHSE is associated with increased risk of cardiovascular mortality and morbidity, we did not find any consistent relationship among SHSE and blood pressure, lipid, or fasting glucose levels in this cross-sectional study. Using objective measurements of urine cotinine did not alter this relationship. Further long-term prospective studies are needed to evaluate the effect of SHSE as a cardiovascular risk factor.

Suboptimal vitamin D status in Korean adolescents: a nationwide study on its prevalence, risk factors including cotinine-verified smoking status and association with atopic dermatitis and asthma

OBJECTIVE

To determine the prevalence and risk factors for suboptimal vitamin D status in Korean adolescents and to assess its relationship with atopic dermatitis (AD) and asthma at a national level.

DESIGN

This is a cross-sectional study with data from the Korean National Health and Nutrition Examination Survey. Information regarding socioeconomic characteristics, clinical data and environmental factors was collected. Blood and urine samples were taken for vitamin D and cotinine, respectively. Descriptive and multivariable logistic regression was performed on the data.

SETTING

South Korea (nationwide).

PARTICIPANTS

2515 individuals aged 10-18 years who participated in the Korean National Health and Nutrition Examination Survey from 2008 to 2011.

MAIN OUTCOME MEASURES

Vitamin D status was determined through measurement of serum 25-hydroxyvitamin D (25OHD). Smoking status was classified based on the urine cotinine level. Physician diagnosed with AD and asthma were assessed using a questionnaire.

RESULTS

Overall, 73.3% of the subjects were vitamin D deficient (25OHD <20 ng/mL) and 24.4% of the subjects were vitamin D insufficient (25OHD, 20-29.9 ng/mL). Older age (p<0.001), female gender (p<0.001), urban residence (p=0.019), higher body mass index (p=0.003) and sampling in winter months (November-March) (p<0.001) were independently associated with low serum 25OHD levels. With cotinine verification, 18.2% of the participants were classified as active smokers, and 43.4% were classified as passive smokers. After adjusting for potential confounders, serum 25OHD status showed no association with AD or asthma.

CONCLUSION

Vitamin D deficiency is highly prevalent in Korean adolescents. Cotinine-verified prevalence of smoking was also high, but its relationship with vitamin D deficiency was not confirmed in our study. Above all, our results provide epidemiological evidence against the association of vitamin D status with AD and asthma at the national level among Korean adolescents.