Sungroul Kim

Assessing secondhand smoke using biological markers

Secondhand smoke exposure (SHSe) is a known cause of many adverse health effects in adults and children. Increasingly, SHSe assessment is an element of tobacco control research and implementation worldwide. In spite of decades of development of approaches to assess SHSe, there are still unresolved methodological issues; therefore, a multidisciplinary expert meeting was held to catalogue the approaches to assess SHSe and with the goal of providing a set of uniform methods for future use by investigators and thereby facilitate comparisons of findings across studies. The meeting, held at Johns Hopkins, in Baltimore, Maryland, USA, was supported by the Flight Attendant Medical Research Institute (FAMRI). A series of articles were developed to summarise what is known about self-reported, environmental and biological SHSe measurements. Non-smokers inhale toxicants in SHS, which are mainly products of combustion of organic materials and are not specific to tobacco smoke exposure. Biomarkers specific to SHSe are nicotine and its metabolites (eg, cotinine), and metabolites of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Cotinine is the preferred blood, saliva and urine biomarker for SHSe. Cotinine and nicotine can also be measured in hair and toenails. NNAL (4-[methylnitrosamino]-1-[3-pyridyl]-1-butanol), a metabolite of NNK, can be determined in the urine of SHS-exposed non-smokers. The selection of a particular biomarker of SHSe and the analytic biological medium depends on the scientific or public health question of interest, study design and setting, subjects, and funding. This manuscript summarises the scientific evidence on the use of biomarkers to measure SHSe, analytical methods, biological matrices and their interpretation.

Overview of Cotinine Cutoff Values for Smoking Status Classification

While cotinine is commonly used as a biomarker to validate self-reported smoking status, the selection of an optimal cotinine cutoff value for distinguishing true smokers from true nonsmokers shows a lack of standardization among studies. This review describes how the cutoff values have been derived, and explains the issues involved in the generalization of a cutoff value. In this study, we conducted an English-language literature search in PubMed using the keywords “cotinine” and “cutoff” or “self-reported” and “smoking status” and “validation” for the years 1985–2014. We obtained 104 articles, 32 of which provided (1) sensitivity and specificity of a cutoff value and (2) determination methods for the given cutoff value. We found that the saliva cotinine cutoff value range of 10–25 ng/mL, serum and urine cotinine cutoff of 10–20 ng/mL and 50–200 ng/mL, respectively, have been commonly used to validate self-reported smoking status using a 2 × 2 table or a receiver operating characteristics (ROC) curve. We also found that recent large population-based studies in the U.S. and UK reported lower cutoff values for cotinine in serum (3 ng/mL) and saliva (12 ng/mL), compared to the traditionally accepted ones (15 and 14 ng/mg, respectively).

Optimum Cutoff Value of Urinary Cotinine Distinguishing South Korean Adult Smokers From Nonsmokers Using Data From the KNHANES (2008–2010)

INTRODUCTION Cutoff values for distinguishing smokers from nonsmokers have generally been derived from studies in White populations. Even though recent population-based studies have demonstrated that cutoff values can differ by race and ethnicity, few studies have explored cutoff values among Asian populations. We established the cutoff values for urinary cotinine and cotinine:creatinine ratio (CCR) using a nationally representative South Korean adult population sample. METHODS Data were obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2010 with pooled sampling weights. Adult participants (n = 11,629) aged ≥19 were included. Optimal cutoff values were determined by performing receiver operating characteristic curve analysis. RESULTS The optimum cutoff values for urinary cotinine and CCR for Korean adults were found to be 164ng/mL and 1122ng/mg, respectively. The application of these urinary cotinine and CCR cutoff values for the female subpopulations aged 19-34, 35-54, and ≥55 years provided sensitivities ranging from 87.1% to 93.8% and from 82.9% to 94.9%, respectively, while maintaining specificity of ≥92%. For the 3 male age-based subpopulations, we obtained sensitivities and specificities for cotinine ranging from 93.1% to 94.5% and from 92.8% to 97.0%, respectively, and for CCR ranging from 90.0% to 96.9% and from 92.2% to 96.8%, respectively. CONCLUSIONS Our cutoff values should allow researchers conducting environmental epidemiological or clinical studies in South Korea to distinguish adult smokers from nonsmokers effectively. However, different values may be applicable for subpopulations with different smoking prevalence rates or higher exposure levels to secondhand smoke.

Exposure to Particulate Matters (PM2.5) and Airborne Nicotine in Computer Game Rooms After Implementation of Smoke-Free Legislation in South Korea

INTRODUCTION In South Korea, computer game rooms are subject to regulations mandating a designated nonsmoking area pursuant to Article 7 of the Enforcement Rules of the National Health Promotion Act; nonsmoking areas must be enclosed on all sides by solid and impermeable partitions. METHODS Using PM(2.5) monitors (SidePak AM510) and airborne nicotine monitors, we measured concentrations in smoking and nonsmoking areas to examine whether separation of the nonsmoking areas as currently practiced is a viable way to protect the nonsmoking area from secondhand smoke exposure. Convenient samplings were conducted at 28 computer game rooms randomly selected from 14 districts in Seoul, South Korea between August and September 2009. RESULTS The medians (interquartile range) of PM(2.5) concentrations in smoking and nonsmoking areas were 69.3 μg/m(3) (34.5-116.5 μg/m(3)) and 34 μg/m(3) (15.0-57.0 μg/m(3)), while those of airborne nicotine were 0.41 μg/m(3) (0.25-0.69 μg/m(3)) and 0.12 μg/m(3) (0.06-0.16 μg/m(3)), respectively. Concentrations of airborne nicotine and PM(2.5) in nonsmoking areas were substantially positively associated with those in smoking areas. The Spearman correlation coefficients for them were 0.68 (p = .02) and 0.1 (p = 0.7), respectively. According to our modeling result, unit increase of airborne nicotine concentration in a smoking area contributed to 7 (95% CI = 2.5-19.8) times increase of the concentration in the adjacent nonsmoking area after controlling for the degree of partition left closed and the indoor space volume. CONCLUSIONS Our study thus provides evidence for the introduction of more rigorous policy initiatives aimed at encouraging a complete smoking ban in such venues.

smoking prevalence and the Association Between smoking and sociodemographic Factors Using the Korea national Health and nutrition examination survey Data, 2008 to 2010

Using data from the Korea National Health and Nutrition Examination Survey collected from 2008 to 2010, smoking prevalence for Korean adults (n = 11,681) by gender and age group and the association between smoking and sociodemographic factors were evaluated. Smoking prevalence was 42.3% for men and 5.6% for women. Young adult (YA) males, ie, 19 to 24 and 25 to 34 years old, were 2.45 (95% CI: 1.60, 3.73) and 5.05 (95% CI: 3.83, 6.66) times more likely to smoke compared to male adults aged 65 and above (31.6%) after controlling for sociodemographic factors. The association between smoking and marital status was different by gender. In South Korea, the high smoking prevalence among young adults is a troubling pattern. The high smoking prevalence among widowed or divorced women is also concern.

Effect of desflurane at less than 1 MAC on QT interval prolongation induced by tracheal intubation

BACKGROUND Desflurane at more than 1 minimum alveolar concentration (MAC) has been shown to prolong the QT interval, but it is unclear whether this is the case at lower concentrations. The aim of this study was to determine whether desflurane concentrations of <1 MAC affect tracheal intubation-induced prolongation of the QT interval. METHODS Forty-four subjects received either inspired desflurane at 1 MAC in oxygen 100% at a fresh gas flow rate of 6 litre min(-1) (desflurane group) or only oxygen 100% (control group) beginning at anaesthesia induction with propofol, before tracheal intubation. The QT intervals were corrected by Bazetts (QTcB) and Fridericias (QTcF) formulae. The primary outcome was the QTcB immediately after tracheal intubation. Secondary outcomes were the interval from the peak to the end of the T wave (Tp-e), mean arterial pressure (MAP), heart rate (HR), and bispectral index (BIS) score. RESULTS The QTc interval immediately after tracheal intubation did not differ between the control and the desflurane groups [QTcB, 451 (sd 23) vs 456 (27) ms, P=0.56; QTcF, 422 (24) vs 429 (22) ms, P=0.31, control vs desflurane group, respectively]. There was no difference in Tp-e or HR between the two groups in this study. However, MAP and the BIS score were significantly lower in the desflurane group until 1 min after tracheal intubation. CONCLUSIONS The administration of desflurane at an inspiratory concentration of 1 MAC during manually controlled ventilation after anaesthesia induction with propofol did not affect tracheal intubation-induced QTc prolongation.

Winter Season Temperature Drops and Sulfur Dioxide Levels Affect on Exacerbation of Refractory Asthma in South Korea: A Time-Trend Controlled Case-Crossover Study Using Soonchunhyang Asthma Cohort Data

Objective. According to the American Thoracic Society, approximately 5% of all asthmatics have refractory asthma (RA); these patients fail to recover lost lung function even after long-term treatment with high doses of medications. Methods. Using a time-trend controlled case-crossover study design, we calculated odds ratios to evaluate whether exposure to ambient air pollutants and certain meteorological conditions on the day of admission (Lag 0) and up to 3 days before admission (Lag1 through Lag 3) were associated with acute RA exacerbation. Results were obtained after controlling for the effects of seasonality, smoking, and allergen sensitivity; we stratified our data into four seasons with respect to the median temperature of each month and further stratified them according to self-reported smoking status and skin-prick test results. Results. In our study, RA patients (n = 82), living in metropolitan city of Seoul and Kyunggi Province, accounted for 3.7% of all asthmatics (n = 2298) registered in our asthma cohort between 2005 and 2009. In winter, a 1°C decrease in ambient temperature and a 1 ppb increase in sulfur dioxide concentration on the day of Lag 1 were associated with 14.8% (95% confidence interval [CI]: 0.9–26.7) and 19.7% (95% CI: 3.3–38.7) increases in the risk of RA exacerbation among nonsmokers, respectively. Similar associations were obtained on the day of Lag 2. The association remained unchanged after excluding patients sensitive to Dermatophagoides farinae and Dermatophagoides pteronyssinus. Conclusions. Exposure to temperature drops and increased sulfur dioxide concentrations are positively associated with the occurrence of acute RA exacerbation during winter with 1 or 2 day lags.

Utility and Cutoff Value of Hair Nicotine as a Biomarker of Long-Term Tobacco Smoke Exposure, Compared to Salivary Cotinine

While hair samples are easier to collect and less expensive to store and transport than biological fluids, and hair nicotine characterizes tobacco exposure over a longer time period than blood or urine cotinine, information on its utility, compared with salivary cotinine, is still limited. We conducted a cross-sectional study with 289 participants (107 active smokers, 105 passive smokers with self-reported secondhand smoke (SHS) exposure, and 77 non-smokers with no SHS exposure) in Baltimore (Maryland, USA). A subset of the study participants (n = 52) were followed longitudinally over a two-month interval. Median baseline hair nicotine concentrations for active, passive and non-smokers were 16.2, 0.36, and 0.23 ng/mg, respectively, while those for salivary cotinine were 181.0, 0.27, and 0.27 ng/mL, respectively. Hair nicotine concentrations for 10% of passive or non-smokers were higher than the 25th percentile value for active smokers while all corresponding salivary cotinine concentrations for them were lower than the value for active smokers. This study showed that hair nicotine concentration values could be used to distinguish active or heavy passive adult smokers from non-SHS exposed non-smokers. Our results indicate that hair nicotine is a useful biomarker for the assessment of long-term exposure to tobacco smoke.

Racial Differences in Hair Nicotine Concentrations Among Smokers

INTRODUCTION In the United States, race/ethnicity is a strong determinant of tobacco use patterns, biomarkers of tobacco smoke components and metabolites, and likelihood of successful cessation. Although Black smokers tend to smoke fewer cigarettes than White smokers, they have higher cotinine levels and disease risk and lower cessation success. We examined racial differences in hair nicotine concentrations among daily tobacco smokers (n = 103) in Baltimore, Maryland. METHODS Participants completed a survey, and hair samples were collected and analyzed for nicotine concentration using gas chromatography coupled with mass spectrometry. RESULTS After adjustment, hair nicotine concentrations among Black smokers were more than 5 times higher than among White smokers (95% CI 3.0, 10.5). Smokers reporting hair treatments other than coloring (bleaching, permanent, or straightening) in the past 12 months had 66% lower (95% CI 32%, 83%) hair nicotine concentrations. Smokers reporting smoking their first cigarette within 30 min of waking had twice the hair nicotine concentrations of those whose time to first cigarette was greater than 30 min after waking (95% CI 1.1, 4.2). For every additional cigarette smoked per day up to 20, mean hair nicotine concentration among all smokers increased by 4% (95% CI -1%, 9%). CONCLUSIONS This study demonstrates that Black smokers have substantially higher hair nicotine levels than White smokers, after controlling for cigarettes smoked per day and other exposure sources. Time to first cigarette, cigarettes smoked per day, and use of hair treatments other than coloring were also associated with hair nicotine concentrations among smokers.

Variations in label information and nicotine levels in electronic cigarette refill liquids in South Korea: regulation challenges

Background: In South Korea, the consumption of liquid nicotine used in electronic cigarettes has dramatically increased from 4310 L in 2012 to 7220 L in 2013. This study aimed to examine the level of heterogeneity of contents of the labels and discrepancy of the nicotine content between that indicated on the label and the actual values for electronic cigarette liquid refill products in South Korea. Methods: We purchased 32 electronic cigarette liquid refill products (17 Korean domestic, 15 imported ones) and one pure nicotine product at six different electronic cigarette retail stores in Seoul between May and June 2014. The actual nicotine concentrations of each product were measured by a blinded analyst at Roswell Park Cancer Institute, Buffalo, NY, USA. Results: Three out of 15 imported liquid refill products provided manufacturing dates, while expiration dates were available on eight products. The range of nicotine concentration was from “not detected” to 17.5 mg/mL. Labeling discrepancies of the concentrations ranged from −32.2% to 3.3% among electronic cigarette liquid refill products. The highest concentration (150.3 ± 7.9 mg/mL) was found in a sample labeled as “pure nicotine”. Conclusions: There is no standardization of labelling among electronic cigarette liquids sampled from retail stores and the labels did not accurately reflect the content. One product labeled “pure nicotine” raises concerns, since it may be poisonous to consumers, especially to children. This study revealed the urgent need for the development of product regulations in South Korea.