Secondhand smoke exposure and serum cotinine levels among current smokers in the USA

The Effect of Adult Smoking Behavior on Children's Exposure to Secondhand Smoke. An Analysis Based on Salivary Cotinine Levels Among Children in Dhaka and Karachi

INTRODUCTION

Exposure to secondhand smoke (SHS) risks children's health. However, biomarkers are rarely used to study SHS exposure among children in low- and middle-income countries.

AIMS AND METHODS

We analyzed cross-sectional data collected between March and November 2022 for a cluster-randomized controlled trial investigating a Smoke-Free Intervention in 2769 children aged 9-15 in 74 schools (34 in Dhaka, Bangladesh, and 40 in Karachi, Pakistan). Children's saliva was tested for the concentration of cotinine-a highly sensitive and specific biomarker for SHS exposure. Based on their reports, children's homes were categorized as Nonsmoking Homes (NSH) when residents were nonsmokers; Smoke-free Homes (SFH) when residents and visitors smoked outdoors only; and Smoke-permitted Homes (SPH) when either residents or visitors smoked indoors. We compared cotinine concentrations across these home types and the two cities using a proportional odds model.

RESULTS

Overall, 95.7% of children (92% in Dhaka; and 99.4% in Karachi) had cotinine levels between 0.1 and 12 ng/mL, indicating SHS exposure. Median cotinine levels were higher in Karachi (0.58 ng/mL, IQR 0.37 to 0.93) than in Dhaka (0.27 ng/mL, IQR 0.16 to 0.49). Median cotinine concentration was also higher among children living in SPH than those in either NSH or SFH; with absolute differences of approximately 0.1-0.3 and 0.05 ng/mL, respectively.

CONCLUSIONS

The level of SHS exposure in Dhaka and Karachi indicates widespread and unrestricted smoking. Smoking restrictions in households and enforcement of smoking bans are urgently needed.

IMPLICATIONS

The high levels of SHS exposure in children living in SFH suggest parental behavior to hide their smoking and/or exposure in private vehicles or public spaces. It is important to advocate for SFH and cars to protect children from SHS exposure. However, these initiatives alone may not be enough. There is a need to enforce smoking bans in enclosed public places and transportation, as well as extend these bans to playgrounds, parks, fairgrounds, and other public spaces that children frequently visit. It is essential to complement smoking restrictions with tobacco cessation advice and support in these settings.

Adapting a Financial Incentives Intervention for Smoking Cessation With Alaska Native Families: Phase 1 Qualitative Research to Inform the Aniqsaaq (To Breathe) Study

INTRODUCTION

Alaska Native and American Indian (ANAI) peoples in Alaska currently experience a disproportionate burden of morbidity and mortality from tobacco cigarette use. Financial incentives for smoking cessation are evidence-based, but a family-level incentive structure has not been evaluated. We used a community-based participatory research and qualitative approach to culturally adapt a smoking cessation intervention with ANAI families.

AIMS AND METHODS

We conducted individual, semistructured telephone interviews with 12 ANAI adults who smoke, 12 adult family members, and 13 Alaska Tribal Health System stakeholders statewide between November 2022 and March 2023. Through content analysis, we explored intervention receptivity, incentive preferences, culturally aligned recruitment and intervention messaging, and future implementation needs.

RESULTS

Participants were receptive to the intervention. Involving a family member was viewed as novel and aligned with ANAI cultural values of commitment to community and familial interdependence. Major themes included choosing a family member who is supportive and understanding, keeping materials positive and encouraging, and offering cash and noncash incentives for family members to choose (eg, fuel, groceries, activities). Participants indicated that messaging should emphasize family collaboration and that cessation resources and support tips should be provided. Stakeholders also reinforced that program materials should encourage the use of other existing evidence-based cessation therapies (eg, nicotine replacement, counseling).

CONCLUSIONS

Adaptations, grounded in ANAI cultural strengths, were made to the intervention and recruitment materials based on participant feedback. Next steps include a beta-test for feasibility and a randomized controlled trial for efficacy.

IMPLICATIONS

This is the first study to design and adapt a financial incentives intervention promoting smoking cessation among ANAI peoples and the first to involve the family system. Feedback from this formative work was used to develop a meaningful family-level incentive structure with ANAI people who smoke and family members and ensure intervention messaging is supportive and culturally aligned. The results provide qualitative knowledge that can inform future family-based interventions with ANAI communities, including our planned randomized controlled trial of the intervention.

Association between tobacco smoke exposure and serum parathyroid hormone levels among US adults (NHANES 2003-2006)

Tobacco smoke exposure has been demonstrated to impede bone remodeling and diminish bone density, yet research regarding its correlation with parathyroid hormone (PTH) remains limited. This study aims to investigate the relationship between tobacco smoke exposure and serum PTH levels in adults aged 20 years and older. This study included 7,641 participants from two cycles of the National Health and Nutrition Examination Survey (NHANES, United States, 2003- 2006). Reflect tobacco smoke exposure through serum cotinine levels, and use an adjusted weighted multivariate linear regression model to test the independent linear relationship between serum cotinine and PTH. Stratified analysis was conducted to validate the sensitivity of the conclusions. Smooth curve fitting and threshold effect analysis were performed to assess the non-linear relationship. After comprehensive adjustment using weighted multivariate regression analysis, a negative correlation was found between serum cotinine and PTH levels. The interaction p-values in subgroup analyses were all greater than 0.05. Moreover, smooth curve fitting indicated a non-linear relationship between serum cotinine and PTH, with a turning point observed. Our research indicates that tobacco smoke exposure is negatively correlated and independent of serum parathyroid hormone levels, indicating that long-term tobacco smoke exposure may lead to parathyroid dysfunction in adults.

Covariation between serum cotinine and blood lead levels among US pediatric populations: Trends from 1999 to 2018

BACKGROUND

Tobacco smoke, including both active and passive smoke, can be an important source of lead exposure. However, the relationship between passive tobacco smoke exposure (PTSE) and blood lead levels (BLL), especially in vulnerable populations, needs to be further explored. The present study was to assess the covariation between serum cotinine, a measure of PTSE, and BLL in a pediatric population during 1999-2018.

METHODS

Data on 21,817 children, aged 3-19 years, was extracted from the biennial nationally representative surveys. The trends of the prevalence of lead exposure (BLL ≥ 3.5 µg/dL) and PTSE (cotinine ≥ 1 ng/mL but < 10 ng/mL) were determined, and the covariation between BLL and cotinine was assessed. The population attributable fraction (PAF) of PTSE to the BLL was proxied using the partial R2 of the hierarchical linear regression. The association between PTSE and lead exposure was estimated using multivariate logistic regression.

RESULTS

A parallel decreasing trend in the prevalence of lead exposure and PTSE was observed. Similarly, the means of both BLL and cotinine declined simultaneously. Overall, the PAF from PTSE towards blood lead was 7 %, doubling the PAF from race/ethnicity and family income combined. Stratified by race/ethnicity, PAF from PTSE was 8 % in Blacks and Whites and 4 % for Hispanics. The odds ratio of PTSE with lead exposure was 2.45 (95 % CI, 1.75, 3.44), 2.00 (1.21, 3.33), and 1.16 (0.64, 2.13) for Black, White, and Hispanic children, respectively. Cotinine mean remained two times higher in Blacks than non-Black children at the end of the study period.

CONCLUSION

Serum cotinine and BLL may have a significant association in children that persists even as both have been steadily declining in recent years. The contribution from PTSE to blood lead variations could be greater than that from socioeconomic factors. Further reducing lead exposure might be achieved by eliminating PTSE, particularly for the Black pediatric population.

Aniqsaaq (To Breathe): Study protocol to develop and evaluate an Alaska Native family-based financial incentive intervention for smoking cessation

Background

Alaska Native and American Indian (ANAI) communities in Alaska are disproportionately affected by commercial tobacco use. Financial incentive interventions promote cigarette smoking cessation, but family-level incentives have not been evaluated. We describe the study protocol to adapt and evaluate the effectiveness and implementation of a remotely delivered, family-based financial incentive intervention for cigarette smoking among Alaskan ANAI people.

Methods

The study has 3 phases: 1) qualitative interviews with ANAI adults who smoke, family members, and stakeholders to inform the intervention, 2) beta-test of the intervention, and 3) randomized controlled trial (RCT) evaluating intervention reach and effectiveness on verified, prolonged smoking abstinence at 6- and 12-months post-treatment. In the RCT, adult dyads (ANAI person who smokes [index participant] and family member) recruited throughout Alaska will be randomized to a no-incentives control condition (n = 328 dyads) or a 6-month incentive intervention (n = 328 dyads). All dyads will receive cessation support and family wellness materials. Smoking status will be assessed weekly for four weeks and at three and six months. Intervention index participants will receive escalating incentives for verified smoking abstinence at each time point (maximum $750 total); the family member will receive rewards of equal value.

Results

A community advisory committee contributed input on the study design and methods for relevance to ANAI people, particularly emphasizing the involvement of families.

Conclusion

Our study aligns with the strength and value AIAN people place on family. Findings, processes, and resources will inform how Indigenous family members can support smoking cessation within incentive interventions.

Clinical Trials Registry

NCT05209451.

Altered platelet reactivity, coagulation, endothelial and inflammatory markers early after smoking cessation verified with cotinine plasma concentration

BACKGROUND/INTRODUCTION

Cigarette smoking is a potent modifiable risk factor for coronary artery disease (CAD). However, little is known about alterations to prothrombotic state and platelet reactivity early after smoking cessation following percutaneous coronary interventions (PCI).

PURPOSE

We investigated alterations to platelet reactivity, coagulation and markers of platelet, endothelial, inflammatory and coagulation activation in clopidogrel-treated patients with CAD after PCI before and after smoking cessation.

METHODS

Smoking patients aged 18 years or older at least 30 days after PCI were recruited and encouraged to quit the habit. At baseline and at 30 days, we measured platelet reactivity with VerifyNow system, thrombomodulin, P-selectin, platelet factor 4 (CXCL4/PF4), citrullinated histone H3 (H3cit) and cotinine level.

RESULTS

Among 117 patients, 84 patients (72%) at a median age of 60.5 years (40 [interquartile range 30-47] pack-years) completed a 30-day follow-up. At day 30, 30 (35.7%) patients stopped smoking with cotinine level < 50 ng/ml. Baseline characteristics were similar in both groups. In smoking quitters a change in platelet reactivity was larger (Δ platelet reactivity units (PRU) 19 [2, 43] vs. -6 [-32, 37], p = 0.018), along with a change in P-selectin concentration (-11.82 [-23.62, 1.34] vs. 7.19 [-14.24, 17.19] ng/ml, p = 0.005). Positive correlations was noticed between cotinine and both P-selectin ( r = 0.23, p = 0.045) and CXCL4 (r = 0.27, p = 0.02).

CONCLUSION

After smoking cessation in CAD patients following PCI an increase in platelet reactivity and a decrease in P-selectin levels were observed. The risk of thrombotic complications post PCI might be paradoxically enhanced among patients who stopped smoking.

Cotinine as a Sentinel of Canine Exposure to Tobacco Smoke

The adverse health effects of both active and passive tobacco smoke have been well-known in humans for a long time. It is presumable that even pets, which intimately share the owner's lifestyle, may be exposed to the same risks. This study aimed to detect and quantify cotinine (a metabolite of nicotine) in the serum and hair of dogs using a specific commercial ELISA immunoassay kit. A total of 32 dogs, 16 exposed and 16 unexposed to the owner's smoke, were enrolled. The cotinine concentration was higher in the exposed than the unexposed group in both matrices (p < 0.001), with greater values in serum than in hair (p < 0.001). Exposed bitches had higher hair cotinine than male dogs (p < 0.001). Conversely, serum and fur cotinine concentrations were lower in female than male dogs of the unexposed group (p < 0.01). The exposure intensity, age, and weight of the dogs did not affect cotinine concentrations. A cut-off value of 2.78 ng/mL and 1.13 ng/mL cotinine concentration in serum and fur, respectively, was estimated to distinguish between the exposed and unexposed dogs. Cotinine was confirmed as a valuable marker of passive smoking also in dogs. Although owners do not perceive secondhand smoke as a risk for their dogs, greater awareness should be advisable, especially in pregnant animals.

Associations of biomarkers for exposure to tobacco smoke with lung cancer risk in Korea

BACKGROUND

Nicotine metabolite ratio (NMR) can be used to predict total nicotine clearance. However, it is unknown whether NMR could be used as a marker of lung cancer risk.

OBJECTIVE

To evaluate the blood metabolites of nicotine relating to the risk of developing lung cancer and investigate the combined effects of NMR and cigarette per day on the risk of lung cancer.

METHODS

Among the 1,054 eligible subjects from the Korean Cancer Prevention Study-II biobank cohort, those with cotinine values below 0 ng/ml were excluded. Slow and fast metabolizer groups were defined using the median value of the NMR, calculated with the control group data, as the cut-point.

RESULTS

The multivariable Cox proportional hazard models demonstrated that, the fast metabolizer group had a significantly higher risk of lung cancer than the slow metabolizer group (Adjusted HR: 2.02, 95% CI: 1.32-3.10). Fast metabolizers who smoked more than 15 cigarettes per day had an even higher risk of lung cancer (Adjusted HR: 3.51, 95% CI: 1.96-6.29) than the slow metabolizers who smoked less than 15 cigarettes per day.

CONCLUSIONS

In summary, the NMR may be an effective marker for estimating tobacco-related disease risks such as lung cancer.

The Association Between Smoking and Renal Function in People Over 20 Years Old

Background

Many conclusions have been reached in renal function studies in direct smokers.

Aim

This study aimed to determine the relationship between smoking and decreased renal function to ensure that reduced chronic kidney disease incidence can be achieved by limiting smoking, we assessed the relationship between cigarette smoking and renal function.

Methods

We recruited 10,267 people from the National Health and Nutrition Program Testing Survey (NHANES) aged over 20 years from 2013 to 2018 to assess smoking exposure by serum cotinine. We estimated the glomerular filtration rate (eGFR) and used multivariate linear regression models and smooth curve fittings to assess the relationship between smoking and renal function.

Results

We found an inverse relationship between serum cotinine and the eGFR. In a subgroup analysis, we found a non-linear relationship between serum cotinine and the eGFR in different ethnic groups or in different sexes. In a subgroup analysis of sex, we found inflection points between men and women for the relationship between serum cotinine and the eGFR (men 183 ng/ml and 465 ng/ml; women 227 ng/ml and 412 ng/ml). However, in a subgroup analysis by age, we found that serum cotinine showed a clear negative correlation with the eGFR in people aged 20–39 years, but in people older than 40 years, a weak correlation was shown. In stratified analysis by ethnicity, we found significant negative associations in Mexican American and Other Hispanic individuals and weaker associations in Non-Hispanic White and Non-Hispanic Black individuals.

Conclusion

Through the negative correlation between serum cotinine and the eGFR, we can conclude that as the smoking quantity increases, smoking leads to a decrease in renal function. The results of the subgroup analysis indicate that in young people, by advocating smoking cessation early, we can very effectively prevent kidney disease in this population and thus reduce the incidence of chronic kidney disease. Smoking should be included as an independent risk factor for chronic kidney disease.

Exposure to Secondhand Smoke: Inconsistency between Self-Response and Urine Cotinine Biomarker Based on Korean National Data during 2009-2018

This study aimed to estimate the secondhand smoke (SHS) exposure using urinary cotinine (UCo) to prove that the SHS exposure could not be properly assessed by self-reporting (SR). In total, 28,574 nonsmokers aged >19 years were selected from the Korean National Health and Nutrition Examination Survey data (2009-2018). First, changes in the annual concentration of UCo were analyzed, and the annual SHS exposure rates were measured based on SR and UCo from 2009 to 2018. Then, the average UCo concentration and UCo-measured SHS exposure rate were confirmed according to the subjects' characteristics. Finally, factors associated with the UCo-measured SHS exposure rate were identified based on multiple regression analysis. The findings showed that the annual UCo concentrations and self-reported SHS exposure rates dropped significantly over the past decade. In contrast, the UCo-measured SHS exposure rate indicated that >80% of nonsmokers are still exposed to SHS. Moreover, we found vulnerable groups using UCo-measured SHS exposure rate. In particular, the self-reported SHS exposure at home and in workplaces and house type was highly associated with SHS exposure. Thus, these findings indicate that the actual SHS exposure could not be properly assessed by SR and should be verified using a biomarker, such as UCo. Considering that even a short-term exposure can be harmful to health, the goal of the policy should be to keep cotinine concentration as low as possible.

Identifying the Best Questions for Rapid Screening of Secondhand Smoke Exposure Among Children

INTRODUCTION

Many children suffer from secondhand smoke exposure (SHSe), which leads to a variety of negative health consequences. However, there is no consensus on how clinicians can best query parents for possible SHSe among children. We employed a data-driven approach to create an efficient screening tool for clinicians to quickly and correctly identify children at risk for SHSe.

METHODS

Survey data from mothers and biospecimens from children were ascertained from the Neurodevelopment and Improving Children's Health following Environmental Tobacco Smoke Exposure (NICHES) study. Included were mothers and their children whose saliva were assayed for cotinine (n = 351 pairs, mean child age = 5.6 years). Elastic net regression predicting SHSe, as indicated from cotinine concentration, was conducted on available smoking-related questions and cross-validated with 2015-2016 National Health and Nutrition Examination Survey (NHANES) data to select the most predictive items of SHSe among children (n = 1670, mean child age = 8.4 years).

RESULTS

Answering positively to at least one of the two final items ("During the past 30 days, did you smoke cigarettes at all?" and "Has anyone, including yourself, smoked tobacco in your home in the past 7 days?") showed area under the curve = .82, and good specificity (.88) and sensitivity (.74). These results were validated with similar items in the nationally representative NHANES sample, area under the curve = .82, specificity = .78, and sensitivity = .77.

CONCLUSIONS

Our data-driven approach identified and validated two items that may be useful as a screening tool for a speedy and accurate assessment of SHSe among children.

IMPLICATIONS

The current study used a rigorous data-driven approach to identify questions that could reliably predict SHSe among children. Using saliva cotinine concentration levels as a gold standard for determining SHSe, our analysis employing elastic net regression identified two questions that served as good classifier for distinguishing children who might be at risk for SHSe. The two items that we validated in the current study can be readily used by clinicians, such as pediatricians, as part of screening procedures to quickly identify whether children might be at risk for SHSe.

Copper associates with differential methylation in placentae from two US birth cohorts

Copper is an essential trace nutrient and an enzymatic cofactor necessary for diverse physiological and biological processes. Copper metabolism is uniquely controlled in the placenta and changes to copper metabolism have been linked with adverse birth outcomes. We investigated associations between patterns of DNA methylation (DNAm; measured at >485 k CpG sites) and copper concentration measured from placentae in two independent mother-infant cohorts: the New Hampshire Birth Cohort Study (NHBCS, n = 306) and the Rhode Island Child Health Study (RICHS, n = 141). We identified nine copper-associated differentially methylated regions (DMRs; adjusted P < 0.05) and 15 suggestive CpGs (raw P < 1e-5). One of the most robust variably methylated CpGs associated with the expression of the antioxidant, GSTP1. Our most robust DMR negatively associates with the expression of the zinc-finger gene, ZNF197 (FDR = 4.5e-11). Genes co-expressed with ZNF197, a transcription factor, are enriched for genes that associate with birth weight in RICHS (OR = 2.9, P = 2.6e-6, N = 194), genes that are near a ZNF197 consensus binding motif (OR = 1.34, P = 0.01, N = 194), and for those classified in GO biological processes growth hormone secretion (P = 3.4e-4), multicellular organism growth (P = 3.8e-4), and molecular functions related to lipid biosynthesis (P = 1.9e-4). Further, putative transcriptional targets for ZNF197 include genes involved in copper metabolism and placentation. Our results suggest that copper metabolism is tied to DNAm in the placenta and that copper-associated patterns in DNAm may mediate normal placentation and foetal development.

Haem iron intake and risk of lung cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort

BACKGROUND

Epidemiological studies suggest that haem iron, which is found predominantly in red meat and increases endogenous formation of carcinogenic N-nitroso compounds, may be positively associated with lung cancer. The objective was to examine the relationship between haem iron intake and lung cancer risk using detailed smoking history data and serum cotinine to control for potential confounding.

METHODS

In the European Prospective Investigation into Cancer and Nutrition (EPIC), 416,746 individuals from 10 countries completed demographic and dietary questionnaires at recruitment. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for incident lung cancer (n = 3731) risk relative to haem iron, non-haem iron, and total dietary iron intake. A corresponding analysis was conducted among a nested subset of 800 lung cancer cases and 1489 matched controls for whom serum cotinine was available.

RESULTS

Haem iron was associated with lung cancer risk, including after adjustment for details of smoking history (time since quitting, number of cigarettes per day): as a continuous variable (HR per 0.3 mg/1000 kcal 1.03, 95% CI 1.00-1.07), and in the highest versus lowest quintile (HR 1.16, 95% CI 1.02-1.32; trend across quintiles: P = 0.035). In contrast, non-haem iron intake was related inversely with lung cancer risk; however, this association attenuated after adjustment for smoking history. Additional adjustment for serum cotinine did not considerably alter the associations detected in the nested case-control subset.

CONCLUSIONS

Greater haem iron intake may be modestly associated with lung cancer risk.

Discrepancies in the Validity of Self-Reported Cigarette Smoking in Adults With and Without ADHD

Objective: Attention-deficit/hyperactivity disorder (ADHD) is associated with an increased smoking prevalence and impairments in executive function, which may negatively affect the validity of self-reported smoking rates. This study compares the utility of self-reported smoking with salivary cotinine in adult smokers and nonsmokers with and without ADHD. Methods: Participants (N = 82) were adult smokers and nonsmokers with and without ADHD (n = 35 ADHD and n = 47 controls) from an observational study. Odds ratios (ORs) for accuracy of self-reported smoking compared to salivary cotinine were calculated using diagnosis (ADHD vs. control), gender, age, education, employment, and number of cigarettes per day as predictors. Post-hoc analysis stratified sensitivity, specificity, and accuracy of self-reported smoking in individuals with ADHD and without ADHD. Results: The initial analysis identified education as a significant independent predictor of odds of accuracy, OR = 6.22, p = .013, after adjusting for diagnosis, gender, age, employment, and cigarettes per day. Post-hoc analysis revealed that sensitivity, specificity, and accuracy of self-reported smoking was 100% for individuals with ADHD who had more than high school education compared to those with high school or less, which was 83.3%, 45.5%, and 65.2%, respectively. Self-reported smoking of control participants with greater than a high school education had a sensitivity of 85.7%, a specificity of 91.7%, and an accuracy of 88.5%. Control participants with a high school or lower education had a sensitivity of 54.6%, a specificity of 90%, and an accuracy of 71.4% for their self-reported smoking. Conclusions: Individuals with ADHD and high school or lower education showed the lowest specificity and accuracy in their self-reported smoking, which may affect documented smoking prevalence rates. This is a secondary analysis of data collected as part of a clinical trial registered as NCT00915798 at www.clinicaltrials.gov .

Acute pulmonary effects of aerosolized nicotine

Nicotine is a highly addictive principal component of both tobacco and electronic cigarette that is readily absorbed in blood. Nicotine-containing electronic cigarettes are promoted as a safe alternative to cigarette smoking. However, the isolated effects of inhaled nicotine are largely unknown. Here we report a novel rat model of aerosolized nicotine with a particle size (~1 μm) in the respirable diameter range. Acute nicotine inhalation caused increased pulmonary edema and lung injury as measured by enhanced bronchoalveolar lavage fluid protein, IgM, lung wet-to-dry weight ratio, and high-mobility group box 1 (HMGB1) protein and decreased lung E-cadherin protein. Immunohistochemical analysis revealed congested blood vessels and increased neutrophil infiltration. Lung myeloperoxidase mRNA and protein increased in the nicotine-exposed rats. Complete blood counts also showed an increase in neutrophils, white blood cells, eosinophils, and basophils. Arterial blood gas measurements showed an increase in lactate. Lungs of nicotine-inhaling animals revealed increased mRNA levels of IL-1A and CXCL1. There was also an increase in IL-1α protein. In in vitro air-liquid interface cultures of airway epithelial cells, there was a dose dependent increase in HMGB1 release with nicotine treatment. Air-liquid cultures exposed to nicotine also resulted in a dose-dependent loss of barrier as measured by transepithelial electrical resistance and a decrease in E-cadherin expression. Nicotine also caused a dose-dependent increase in epithelial cell death and an increase in caspase-3/7 activities. These results show that the nicotine content of electronic cigarettes may have adverse pulmonary and systemic effects.

Misclassification of self-reported smoking in adult survivors of childhood cancer

We investigated misclassification rates, sensitivity, and specificity of self-reported cigarette smoking through serum cotinine concentration (liquid chromatography tandem mass spectrometry) among 287 adult survivors of childhood cancer. Overall, 2.5-6.7% and 19.7-36.9% of the self-reported never and past smokers had cotinine levels indicative of active smoking. Sensitivity and specificity of self-reported smoking were 57.5-67.1% and 96.6-99.2%. Misclassification was associated with younger age (OR = 3.2; 95% CI = 1.4-7.4), male (OR = 2.1; 95% CI = 1.1-4.0), and past (OR = 2.7; 95% CI = 1.3-5.8) or current (OR = 2.6; 95% CI = 1.0-6.6) marijuana use. After adjusting for tobacco-related variables, current marijuana use remained a significant risk for misclassification. Clinicians/researchers should consider bio-verification to measure smoking status among survivors.

Tobacco Use and Prevalence of Human Papillomavirus in Self-Collected Cervicovaginal Swabs Between 2009 and 2014

OBJECTIVE

To evaluate relationships between an objective biomarker of current tobacco exposure and high-risk genital human papillomavirus (HPV) prevalence among adult women in the United States.

METHODS

We performed a retrospective analysis of adult women (aged 18-59 years) using three consecutive 2-year cycles (2009-2014) from the cross-sectional National Health and Nutrition Examination Surveys. Women who provided self-collected cervicovaginal swabs and serum were included. Human papillomavirus genotyping was conducted on cervicovaginal samples with a Linear Array HPV assay. Cotinine, a major metabolite of nicotine, was assayed from serum to provide a biomarker of recent tobacco exposure. Participants were stratified into three levels of tobacco exposure (nonsmokers, secondhand smoke exposure, and smokers) based on serum cotinine concentration levels using previously published ethnic-specific cut points. Weighted percentages are provided to account for unequal selection probabilities among participants and adjustments for nonresponse.

RESULTS

Among the 5,158 women analyzed, 2,778 were classified as nonsmokers (57.1%, 95% CI 54.5-59.6%), 1,109 classified as having secondhand smoke exposure (18.4%, 95% CI 16.5-20.3%), and 1,271 classified as smokers (24.6%, 95% CI 22.8-26.5%) using serum cotinine concentration levels. Prevalence of HPV infection differed between nicotine exposure groups (P<.001): 441 smokers (32.1%, 95% CI 29.6-34.7%), 322 women with secondhand smoke exposure (26.1%, 95% CI 22.7-29.7%), and 451 nonsmokers (15.1%, 95% CI 13.3-17.1%) had a high-risk genital HPV infection. Controlling for demographics and number of lifetime sexual partners, the risks compared with nonsmokers for infection with a high-risk HPV genotype for smokers (adjusted odds ratio [OR] 1.7, 95% CI 1.4-22) and secondhand smokers (adjusted OR 1.4, 95% CI 1.1-1.8) are similarly increased (P<.001).

CONCLUSION

In this large cross-sectional, population-based study, we show a relationship between an objective biomarker of current tobacco use and genital HPV infection. Cigarette smoking and exposure to secondhand smoke are associated with increased odds of infection with high-risk genital HPV independent of lifetime number of sexual partners.

Environmental Tobacco Exposure and Urinary Cotinine Levels in Smoking and Nonsmoking Adolescents

Objective

We aimed to evaluate the association between environmental tobacco smoke (ETS) exposure and urinary cotinine levels in current adolescent smokers and nonsmokers. The secondary objective was to explore the association between ETS exposure and nicotine dependence in adolescent smokers.

Methods

Using the results from a validation study for the 2012 Global Youth Tobacco Survey in Mexico, we quantified urinary cotinine levels in adolescent smokers and nonsmokers. We fitted a multivariate regression model to assess the association between household exposure to ETS and cotinine levels in adolescent smokers and nonsmokers. In addition, using the questionnaire's answers for morning cravings, we fitted a multivariate Poisson regression model to explore the association between household ETS exposure and nicotine dependence in adolescent smokers.

Results

For each day of household ETS exposure, cotinine levels increase by 5% in adolescent smokers compared to a 2% increase in nonsmokers, adjusting for the number of cigarettes smoked per week, age and sex (exp(β) 1.05; 95% confidence interval [CI] [1.00, 1.10]; p = .041). Morning cravings increase 11% for each day of household ETS exposure adjusting for the number of cigarettes smoked per week, age and sex (prevalence ratio [PR] 1.11; 95% CI [0.99, 1.25]; p = .064).

Conclusions

There is an association between ETS exposure and cotinine levels, and ETS may contribute to nicotine dependence in adolescent smokers. If confirmed, avoiding ETS exposure could prove helpful for addiction control and quitting in adolescents.

Implications

Evidence suggests that ETS increases cotinine levels in nonsmokers and adult smokers. However, no study has explored the association between ETS exposure and cotinine levels and addiction in adolescent smokers. This paper provides evidence of an association between ETS exposure and cotinine levels in adolescent smokers: each day of environmental tobacco smoke exposure at home increased cotinine levels by 5% among smokers. In addition, morning cravings in adolescent smokers increased 11% for every day of ETS exposure. ETS exposure is a significant source of nicotine for adolescent smokers and could play an important role in addiction.

Cadmium and lead exposure and risk of cataract surgery in U.S. adults

Cataract is a major cause of visual dysfunction and the leading cause of blindness. Elevated levels of cadmium and lead have been found in the lenses of cataract patients, suggesting these metals may play a role in cataract risk. This study aimed to examine the associations of blood lead, blood cadmium and urinary cadmium with cataract risk. We identified 9763 individuals aged 50 years and older with blood lead and cadmium levels, and a randomly selected subgroup of 3175 individuals with available urinary cadmium levels, from the National Health and Nutrition Examination Surveys (NHANES) from 1999 to 2008 (mean age=63years). Participants were considered to have cataract if they self-reported prior cataract surgery in NHANES's vision examination. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed using survey logistic regression models. We identified 1737 cataract surgery cases (the weighted prevalence=14.1%). With adjustment for age, race/ethnicity, gender, education, diabetes mellitus, body mass index, cigarette smoking (serum cotinine and pack-years) and urine hydration, every 2-fold increase in urinary cadmium was associated with a 23% higher risk of cataract surgery (OR=1.23, 95% CI: 1.04, 1.46, p=0.021). We found no associations of cataract surgery with blood cadmium (OR=0.97, 95% CI: 0.89, 1.07) and blood lead (OR=0.97, 95% CI: 0.88, 1.06). Mediation analysis showed that for the smoking-cadmium-cataract pathway, the ratio of smoking's indirect effect to the total effect through cadmium was more than 50%. These results suggest that cumulative cadmium exposure may be an important under-recognized risk factor for cataract. However, these findings should be interpreted with a caution because of inconsistent results between urinary cadmium and blood cadmium.

Combination Extended Smoking Cessation Treatment Plus Home Visits for Smokers With Schizophrenia: A Randomized Controlled Trial

INTRODUCTION

The majority of people with schizophrenia have a diagnosis of tobacco dependence during their lifetime. A major obstacle to reducing the burden of cigarette smoking in this population is that these smokers have lower quit rates when undergoing standard treatment compared to smokers with no mental illness. We sought to determine if combination extended treatment (COMB-EXT) and home visits (HV) would lead to improved outcomes in smokers with schizophrenia.

METHODS

Thirty-four cigarette smokers with schizophrenia completed either COMB-EXT with HV, COMB-EXT without HV, or treatment as usual (TAU) (random assignment). COMB-EXT consisted of group cognitive-behavioral therapy (CBT), bupropion, nicotine patch, and nicotine lozenge, which were initiated within 2 weeks and continued for 26 weekly visits. HV consisted of biweekly visits to the home with assessment of secondhand smoke (SHS) exposure and brief behavioral therapy with participants and others in the home environment. TAU consisted of group CBT plus serial single or combination medication trials as per standard care.

RESULTS

Smokers with schizophrenia who received COMB-EXT (with or without HV) had greater reductions in cigarettes per day than those treated with TAU (both ps < .01). In addition, 7-day point prevalence abstinence rates for the three groups were 45%, 20%, and 8%, respectively, which was significantly higher for COMB-EXT plus HV than TAU (χ²(1) = 4.8, p = .03). Groups did not differ significantly in the number of adverse events, and HV were easily scheduled.

CONCLUSION

COMB-EXT improves outcomes for smokers with schizophrenia. HV appeared to provide additional benefit for smoking cessation in this treatment-resistant population.

IMPLICATIONS

The clear benefit found here of rapidly initiated, combination, extended treatment over TAU suggests that aggressive and extended treatment should be considered in clinical practice for smokers with schizophrenia. Furthermore, HV to address SHS exposure showed initial promise for assisting smokers with schizophrenia in maintaining abstinence, indicating that this intervention may be worthy of future research.