Misclassification of smoking in a follow-up population study in southern Germany

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).

Lifestyle factors and contact to general practice with respiratory alarm symptoms-a population-based study

Background

A prerequisite for early lung cancer diagnosis is that individuals with respiratory alarm symptoms (RAS) contact a general practitioner (GP). This study aims to determine the proportion of individuals in the general population who contact a GP with RAS and to analyse the association between lifestyle factors and contact to GPs with RAS.

Methods

A web-based survey of 100 000 individuals randomly selected from the Danish Civil Registration System. Items regarding experience of RAS (prolonged coughing, shortness of breath, coughing up blood, and prolonged hoarseness), GP contacts, and lifestyle factors (smoking status, alcohol intake, and body mass index) were included.

Results

In total 49 706 (52.5 %) individuals answered the questionnaire. Overall 7870 reported at least one respiratory alarm symptom, and of those 39.6 % (3 080) had contacted a GP. Regarding specific symptoms, the proportion of individuals that had contacted a GP varied from 27.4 % (prolonged hoarseness) to 47.9 % (shortness of breath). Being a woman and increasing age were significantly associated with a higher proportion of GP contacts. For both genders, current smoking and alcohol intake were significantly associated with lower odds of contacting a GP.

Conclusion

Among individuals with RAS, less than one-half contacted a GP. Gender, age, smoking status, and alcohol intake significantly influenced whether individuals with RAS contacted a GP.

Trial registration

The project has been approved by the Danish Data Protection Agency (journal no. 2011-41-6651).

Lifestyle factors and experience of respiratory alarm symptoms in the general population

Background

The first step in the diagnosis of lung cancer is for individuals in the general population to recognise respiratory alarm symptoms (RAS). Knowledge is sparse about RAS and factors associated with experiencing RAS in the general population. This study aimed to estimate the prevalence of RAS in the general population, and to analyse possible associations between lifestyle factors and experiencing RAS.

Methods

A web-based survey comprising 100 000 individuals randomly selected from the Danish Civil Registration System. Items regarding experience of RAS (prolonged coughing, shortness of breath, coughing up blood and prolonged hoarseness) and self-reported lifestyle factors (smoking status, alcohol intake and body mass index) were included in the analysis.

Results

A total of 49 706 individuals completed the questionnaire. 16 per cent reported at least one RAS. Prolonged coughing (8.4%) and shortness of breath (8%) were most prevalent, while coughing up blood was least prevalent (0.1%). More men than women reported RAS (p<0.001). Odds of reporting RAS increased with age (P_trend<0.001). In men and women, former and current smoking was associated with reporting at least one RAS (former smoking: OR_men=1.42, 95% CI 1.39 to 1.56; OR_women=1.25, 95% CI 1.15 to 1.36; current smoking: OR_men=2.58, 95% CI 2.35 to 2.83; OR_women=2.45, 95% CI 2.25 to 2.68). Individuals who were underweight or obese were significantly more likely to report at least one RAS. Odds of reporting at least one RAS increased with increasing alcohol intake for both genders (P_trend<0.001).

Conclusions

RAS are common in the general population. Men experience more symptoms than women, and prevalence increases with age. Being a former or current smoker and being underweight or obese are positively associated with experiencing RAS. The likelihood of experiencing RAS increases with increasing alcohol intake. Future research should investigate healthcare seeking for RAS among individuals with different lifestyles.

An integrated inspection of the somatic mutations in a lung squamous cell carcinoma using next-generation sequencing

Squamous cell carcinoma (SCC) of the lung kills over 350,000 people annually worldwide, and is the main lung cancer histotype with no targeted treatments. High-coverage whole-genome sequencing of the other main subtypes, small-cell and adenocarcinoma, gave insights into carcinogenic mechanisms and disease etiology. The genomic complexity within the lung SCC subtype, as revealed by The Cancer Genome Atlas, means this subtype is likely to benefit from a more integrated approach in which the transcriptional consequences of somatic mutations are simultaneously inspected. Here we present such an approach: the integrated analysis of deep sequencing data from both the whole genome and whole transcriptome (coding and non-coding) of LUDLU-1, a SCC lung cell line. Our results show that LUDLU-1 lacks the mutational signature that has been previously associated with tobacco exposure in other lung cancer subtypes, and suggests that DNA-repair efficiency is adversely affected; LUDLU-1 contains somatic mutations in TP53 and BRCA2, allelic imbalance in the expression of two cancer-associated BRCA1 germline polymorphisms and reduced transcription of a potentially endogenous PARP2 inhibitor. Functional assays were performed and compared with a control lung cancer cell line. LUDLU-1 did not exhibit radiosensitisation or an increase in sensitivity to PARP inhibitors. However, LUDLU-1 did exhibit small but significant differences with respect to cisplatin sensitivity. Our research shows how integrated analyses of high-throughput data can generate hypotheses to be tested in the lab.

The association of active smoking with multiple cancers: national census-cancer registry cohorts with quantitative bias analysis

PURPOSES

(1) Determine the association of multiple cancers with smoking, focusing on cancers with an uncertain association; and (2) illustrate quantitative bias analysis as applied to registry data, to adjust for misclassification of smoking and residual confounding by alcohol and obesity.

METHODS

New Zealand 1981 and 1996 censuses, including smoking questions, were linked to cancer registry data giving 14.8 million person-years of follow-up. Rate ratios (RR) for current versus never smokers, adjusting for age, sex, ethnicity and socioeconomic factors were calculated and then subjected to quantitative bias analysis.

RESULTS

RR estimates for lung, larynx (including ear and nasosinus), and bladder cancers adjusted for measured confounders and exposure misclassification were 9.28 (95 % uncertainty interval 8.31-10.4), 6.14 (4.55-8.30), and 2.22 (1.94-2.55), respectively. Moderate associations were found for cervical (1.82; 1.51-2.20), kidney (1.29; 1.07-1.56), liver cancer (1.75; 1.37-2.24; European only), esophageal (2.14; 1.73-2.65), oropharyngeal (2.30; 1.94-2.72), pancreatic (1.68; 1.44-1.96), and stomach cancers (1.42; 1.22-1.66). Protective associations were found for endometrial (0.67; 0.56-0.79) and melanoma (0.72; 0.65-0.81), and borderline association for thyroid (0.76; 0.58-1.00), colon (0.89; 0.81-0.98), and CML (0.66; 0.44-0.99). Remaining cancers had near null associations. Adjustment for residual confounding suggested little impact, except the RRs for endometrial, kidney, and esophageal cancers were slightly increased, and the oropharyngeal and liver (European/other) RRs were decreased.

CONCLUSIONS

Our large study confirms the strong association of smoking with many cancers and strengthens the evidence for protective associations with thyroid cancer and melanoma. With large data sets, considering and adjusting for residual systematic error is as important as quantifying random error.

Missing, unreplaced teeth and risk of all-cause and cardiovascular mortality

BACKGROUND

A dentition of at least 20 teeth is associated with sufficient masticatory efficiency and is a stated health goal of the World Health Organisation. We examined whether subjects with missing, unreplaced teeth had an increased mortality risk.

METHODS

We used data prospectively collected from those participants in the population-based Study of Health in Pomerania who had fewer than 20 remaining teeth, resulting in a sample of 1803 participants with a median age of 64 years. Of those, 188 subjects had 9 or more unreplaced teeth. During a median follow-up period of 9.9 years, 362 subjects died, 128 of whom of cardiovascular causes.

RESULTS

We found that having 9 or more unreplaced teeth was related to all-cause mortality (rate ratio 1.53, 95% CI: 1.11-2.10; adjusted for variables according to causal diagrams: remaining teeth, age, sex, education, income, marital status, partnership, and oral health behaviour) and cardiovascular mortality (rate ratio 1.94, 95% CI: 1.15-3.25). When adjusting not only for the variables according to causal diagrams but also for smoking, alcohol consumption, physical activity, obesity, hypertension, diabetes, and dyslipidemia, the rate ratio was 1.43 (95% CI: 1.05-1.96) for all-cause mortality and 1.88 (95% CI: 1.10-3.21) for cardiovascular mortality.

CONCLUSIONS

A reduced, unrestored dentition is associated with increased mortality risk. Thus, clinicians and dietitians have a responsibility to consider individual chewing ability in nutritional recommendations.

Maternal smoking during pregnancy and risk for childhood leukemia: a nationwide case-control study in Greece and meta-analysis

BACKGROUND

Maternal smoking during pregnancy has been often implicated in the development of childhood leukemia with ambiguous results. Hence, we conducted a meta-analysis aiming to summarize current evidence and quantify any tentative impact.

PROCEDURE

We retrieved one cohort (553 leukemias compared to 1,440,542 children), 20 case-control studies and also analyzed the updated Greek case-control dataset with unpublished data, yielding in total 11,092 cases and 25,221 controls.

RESULTS

Odds ratios reported in the studies included ranged from 0.70 to 2.20 for acute lymphocytic (ALL) and from 0.60 to 2.17 for acute myelocytic leukemia (AML). The combined effect regarding the association of maternal smoking (any vs. no) and leukemia risk was 1.03 for ALL (95% CI = 0.95-1.12, random effects model) and 0.99 for AML (95% CI = 0.90-1.09, fixed effects model). The results remained unchanged when sensitivity analyses were undertaken of studies reporting same maternal smoking periods, those focusing only on childhood leukemia deaths or investigations which did not clearly define AML subtype.

CONCLUSIONS

The findings of the meta-analysis challenge the limits of traditional epidemiology to provide sound inferences when point estimates of constituent studies range around the null. In particular, this study provides no support to a hypothesis linking maternal smoking during pregnancy with subsequent development of main childhood leukemia subtypes. Further investigations employing molecular and genetic epidemiology, however, might be needed in the hope to reveal even minimal risks pertaining individuals with specific susceptibility to tobacco compounds who sustain high environmental exposures prenatally or postnatally.

Maternal smoking during pregnancy and childhood lymphoma: a meta-analysis

Results from epidemiological studies exploring the association between childhood lymphoma and maternal smoking during pregnancy have been contradictory. This meta-analysis included all published cohort (n = 2) and case-control (n = 10) articles; among the latter, the data of the Greek Nationwide Registry for Childhood Hematological Malignancies study were updated to include all recently available cases (-2008). Odds ratios (ORs), relative risks and hazard ratios were appropriately pooled in three separate analyses concerning non-Hodgkin lymphoma (NHL, n = 1,072 cases), Hodgkin lymphoma (HL, n = 538 cases) and any lymphoma (n = 1,591 cases), according to data availability in the included studies. An additional metaregression analysis was conducted to explore dose-response relationships. A statistically significant association between maternal smoking (any vs. no) during pregnancy and risk for childhood NHL was observed (OR = 1.22, 95% confidence interval, CI: 1.03-1.45, fixed effects model), whereas the risk for childhood HL was not statistically significant (OR = 0.90, 95% CI: 0.66-1.21, fixed effects model). The analysis on any lymphoma did not reach statistical significance (OR = 1.10, 95% CI = 0.96-1.27, fixed effects model), possibly because of the case-mix of NHL to HL. No dose-response association was revealed in the metaregression analysis. In conclusion, this meta-analysis points to a modest increase in the risk for childhood NHL, but not HL, among children born by mothers smoking during pregnancy. Further investigation of dose-response phenomena in the NHL association, however, warrants accumulation of additional data.

Smoking and atherosclerotic cardiovascular disease: part II: role of cigarette smoking in cardiovascular disease development

Potential mechanisms and biomarkers of atherosclerosis related to cigarette smoking - a modifiable risk factor for that disease - are discussed in this article. These include smoking-associated inflammatory markers, such as leukocytes, high-sensitivity C-reactive protein, serum amyloid A, ICAM-1 and IL-6. Other reviewed markers are indicative for smoking-related impairment of arterial endothelial function (transcapillary leakage of albumin, inhibition of endogenous nitric oxide synthase activity and reduced endothelium-dependent vasodilation) or point to oxidative stress caused by various chemicals (cholesterol oxidation, autoantibodies to oxidized low-density lipoprotein, plasma levels of malondialdehyde and F(2)-isoprostanes and reduced antioxidant capacity). Smoking enhances platelet aggregability, increases blood viscosity and shifts the pro- and antithrombotic balance towards increased coagulability (e.g., fibrinogen, von Willebrand factor, ICAM-1 and P-selectin). Insulin resistance is higher in smokers compared with nonsmokers, and hemoglobin A1c is dose-dependently elevated, as is homocysteine. Smoke exposure may influence the kinetics of markers with different response to transient or chronic changes in cigarette smoking behavior.

Variation in tobacco use profiles obtained from periodontal maintenance patients

OBJECTIVES

To compare methods of tobacco use profiling in patients undergoing maintenance treatment for periodontitis.

METHODS

The smoking status of 108 subjects attending a university-based specialist periodontics clinic was assessed by examination of referring records, patient-completed questionnaires, clinician-administered interviews and by salivary cotinine and expired-air carbon monoxide (ECO) measurement.

RESULTS

Ten percent of the detected smokers (salivary cotinine>14.2ngml(-1)) reported to be non-smokers in the clinician-administered interview. 4.2% of the smokers detected by ECO analysis (ECO>8ppm) reported to be non-smokers in the clinician-administered interview. Systematic under reporting of tobacco use was also apparent in patient-completed questionnaires from the periodontics clinic and, to a larger degree, in the referring clinic records when compared to the clinician-administered interview.

CONCLUSIONS

By biochemically analyzing recent cigarette smoke exposure, our data show that clinician assessment is the most accurate means by which to obtain anamnestic data concerning tobacco use. ECO analysis using portable CO monitors is inexpensive and simple with no requirement for laboratory support. The combination of ECO measurement and clinician-administered tobacco use interview represents a clinically applicable method to improve the detection of an important, periodontally susceptible population-regular smokers who deny smoking.

Environmental tobacco smoke exposure and respiratory morbidity in children

Environmental tobacco smoke (ETS) contains carcinogenic and toxic agents. Smoking might have a more serious effect on children than adults. We aimed to examine the effects of passive smoking on pulmonary function and respiratory health in children and to assess the concordance between parental self-reported smoking habits and urinary cotinine levels in their children. This cross-sectional study was conducted in the winter with the participation of 131 children (9-12 yr old). The procedure for each subject consisted of administration of a questionnaire to the parents, and collection of a urine sample and measurement of lung function in each child. Cotinine level excreted into urine was analyzed with respect to parental self-reported smoking behavior. Working mothers and mothers with higher level of education tended to smoke more at home (p values, respectively, .002 and .005). There was a statistical difference between the urinary cotinine levels of children when divided into two groups according to their fathers' smoking behavior at home (p = .0001). No statistically significant difference was determined in the mean episodes of respiratory infections treated during the last 12 mo among the groups formed according to daily number of cigarettes smoked by the parents at home (1: not exposed; 2: < 5 cigarettes; 3: 5-10 cigarettes; 4: > 10 cigarettes), or among the groups formed according to urinary cotinine levels (1: < 10 ng/ml; 2: > or =10 ng/ml). No significant difference was demonstrated in any of the respiratory function parameters investigated between the groups considered. The reliability of the declarations of the parents in the estimation of ETS exposure of children was low. Children are unable to remove themselves from ETS exposure. It is better to reduce the percentage of parents who smoke rather than to isolate smokers or increase ventilation.

Lung cancer and occupation in nonsmokers: a multicenter case-control study in Europe

BACKGROUND

Tobacco smoking is the main cause for lung cancer worldwide, making it difficult to examine the carcinogenic role of other risk factors because of possible confounding by smoking. Therefore, the present study aimed to investigate the association between lung cancer and occupation independent of smoking.

METHODS

A case-control study of lung cancer was carried out between March 1998 and January 2002 in 16 centers from 7 European countries, including 223 never-smoking cases and 1039 controls. Information on lifestyle and occupation was obtained through detailed questionnaires. Job and industries were classified as entailing exposure to known or suspected carcinogens; in addition, expert assessment provided exposure estimates to specific agents.

RESULTS

The odds ratio of lung cancer among women employed for more than 12 years in suspected high-risk occupations was 1.75 (95% confidence interval = 0.63-4.85). A comparable increase in risk was not detected for employment in established high-risk occupations or among men. Increased risk of lung cancer was suggested among individuals exposed to nonferrous metal dust and fumes, crystalline silica, and organic solvents.

CONCLUSION

Occupations were found to play a limited role in lung cancer risk among never-smokers. Jobs entailing exposure to suspected lung carcinogens should receive priority in future studies among women. Nonferrous metal dust and fumes and silica may exert a carcinogenic effect independently from smoking.

Self-Reported and Serum Cotinine-Validated Smoking in Pregnant Women in Estonia

OBJECTIVES

Although widely used in epidemiological studies, self-report has been shown to underestimate the prevalence of smoking among pregnant women. Objectives of this study were to examine the discrepancy between self-reported and cotinine-validated smoking status, and the sociodemographic characteristics associated with the misclassification of real smoking status among pregnant women in Tallinn, the capital of Estonia.

METHODS

Serum cotinine assays were performed on a subsample (n = 1360) of the pregnant women, who had participated in a recent study of human papillomavirus type 16 (HPV-16) seroprevalence in Estonia. In the present study, serum concentrations > or = 15 ng/ml were used to distinguish current smokers from nonsmokers. The serum-validated smoking level was compared with the self-reported level in the records of the Estonian Medical Birth Registry. For the group of self-reported non-smokers, the differences between the cotinine-validated smokers and the cotinine-validated nonsmokers, with respect to their sociodemographic characteristics (age, ethnicity, educational level, employment status, marital status, parity), were estimated by logistic regression.

RESULTS

Of 1239 women who reported being nonsmokers, 259 (20.9%) had serum cotinine levels > or = 15 ng/ml, and can be regarded as current smokers. Among self-reported nonsmokers, nondisclosure of current smoking was significantly more frequent in non-Estonian, less educated, socially inactive, cohabiting and multiparous women.

CONCLUSIONS

Self-reported data on smoking in pregnant women underestimates the real smoking prevalence in Estonia. Maternal unwillingness to declare smoking during pregnancy needs to be taken into account in the practice of maternal and child health to better target prenatal smoking cessation interventions.

Biomarkers of exposure to passive smoking of school children: frequency and determinants

This study aims to assess the extent of children' exposure to ETS and quantify potential determinants. A total of 2767 children aged 5-14 years participated in an environmental survey in East Germany in 1998-1999 (participation rate 75.9%). A subgroup of 979 children between the ages of 11 and 14 years with complete data on nicotine and cotinine in urine were selected for this analysis. This study population consisted of 73 self-reported smokers (7.5%), 793 non-smokers (81%) and 113 children with missing data on smoking status (11.5%). Nicotine and cotinine concentrations in spontaneous urine sample were determined by high-performance liquid chromatography methods with ultraviolet-detection and corrected for creatinine. Approximately 40% of self-reported non-smokers were exposed to environmental tobacco smoke (ETS) at home. Non-smoking children exposed to parental tobacco smoke at home compared with not exposed showed in average higher nicotine and cotinine concentration (geometric mean 4.7 microg/l vs. 1.4 microg/l and 8.1 microg/l vs. 2.7 microg/l) and the adjusted odds ratio (OR) for detectable biomarkers ranged between 17 and 22. There were increased rates of detectable biomarkers in urine with increasing numbers of smoked cigarettes in the household (adjusted OR increased from 8 to 54). Maternal smoking showed a stronger effect than paternal smoking. Furthermore, low parental education, cold season, height of dwelling (<or=2.40), urine collected on Monday were statistically significant associated with high nicotine and cotinine excretion levels. Children exposed to parental smoke showed much higher biomarker levels than the non-smoking spouse of an adult smoker. Therefore, children need specifically protection from ETS at home.

PRACTICAL IMPLICATIONS

As children showed a higher internal exposure compared with adults the health hazards association with passive smoking might have a more serious effect in children. Children are unable to complain and unable to remove themselves from tobacco smoke exposure. Thus, parents should make sure that their children live in a smoke free environment. Each country should take all necessary legislative and regulatory measures which forbids smoking in public places and the home environment even if it requires sacrifices by the parents.

Prevalence of maxillary sinus disease and abnormalities in patients scheduled for sinus lift procedures

BACKGROUND

The purpose of the present study was to determine the prevalence of sinus disease and abnormalities among patients scheduled to undergo direct sinus augmentation.

METHODS

Forty-five patients attending a private periodontal practice and consecutively treatment planned for sinus augmentation were referred for otorhinolaryngologic evaluation, which included a medical history and radiographic (computed tomography), clinical, and endoscopic examinations. Pathological findings were recorded and otorhinolaryngologic treatment was provided. Six months later the sinus augmentation procedure was performed and followed by postoperative evaluations for 4 to 6 months.

RESULTS

Of the 45 subjects, 98% (44) were diagnosed with chronic periodontitis, 51% were smokers, and 27% reported a history of symptoms indicative of sinus disease. Eighteen subjects were diagnosed with sinus disease and/or abnormalities. The diagnosed conditions included chronic sinusitis, sinus cysts, nasal septum deviation, and ostium stenosis. No significant differences in age, gender, or smoking status between patients with and without sinus conditions were found (P >0.05). There was a significant association between history of symptoms and diagnosis of sinus conditions (P <0.0001). Three subjects (one treated for preoperative sinus conditions) experienced notable intra- or postoperative complications related to the sinus augmentation procedure.

CONCLUSIONS

The results indicate that, in a population of patients with chronic periodontitis, presence of sinus conditions is strongly associated with a history of indicative symptoms and is independent of age, gender, and smoking status. The results reinforce the importance of careful detailed history taking and thorough clinical and radiographic evaluation prior to performing sinus augmentation.

Periodontal Conditions in an Elderly Japanese Population Influenced by Smoking Status and Serum Immunoglobulin G2 Levels

BACKGROUND

A Japanese population residing in the same area may be suitable for evaluation of the association among IgG subclass levels, smoking status, and periodontal disease due to similar racial and environmental factors, as these factors can interact to influence serum IgG subclass levels. The present cross-sectional investigation attempted to examine the influence of serum IgG subclass levels and smoking status on periodontal condition in a population of elderly Japanese subjects.

METHODS

Elderly individuals (N = 451, age, 71 years) residing in Niigata City, Japan participated in the present study. Clinical evaluations, which consisted of probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), and calculus, and serological determinations including serum IgG subclass levels and anti-Porphyromonas gingivalis fimbriae IgG subclass titers were conducted. All participants were asked to complete questionnaires regarding smoking status and were then divided into one of three groups: never smoker, former smoker, or current smoker.

RESULTS

Distributions of the number of teeth did not differ significantly across the groups. The proportion of sites with CAL > or =4 mm (%CAL4) in current smokers was significantly higher in comparison with never smokers. Multiple linear regression analysis revealed that %CAL4 was influenced by number of teeth, serum IgG2 levels, gender, and smoking status (R(2) = 0.253, P < 0.001). The effect of IgG2 was greater than that of smoking status. Distribution of IgG2 was not significantly different across the three groups.

CONCLUSION

These data indicate that serum IgG2 levels influences periodontal conditions in an elderly Japanese population independent of smoking status.

Nicotine and cotinine in adults' urine: The German Environmental Survey 1998

In 1998, the German Environmental Survey (GerES III) recruited approximately 5000 adults between the ages of 18 and 69 years. The study population for these analyses consisted of 1580 smokers (34% of the total population) and 3126 nonsmokers. Nicotine and cotinine concentrations in urine were determined by HPLC methods with UV-detection and corrected for creatinine. Nicotine and cotinine concentrations differed between smokers and nonsmokers by factors of 10-100. The multiple linear regression models used for the analyses of nicotine detection in the urine of smokers explained 43.2% and 42.3% of the total volume-specific and creatinine-specific variances, respectively. Cigarette smoking was the major factor responsible for 41% of the total variance. The explained variances of the cotinine results were larger, 51.0% and 49.3% of the total variance were volume-specific and creatinine-specific, respectively. More than 20% of nonsmokers in GerES III were exposed to environmental tobacco smoke at home, at work or in other places. The logistic regression analysis approach used for the group of nonsmokers showed the greatest effects for those exposed to tobacco smoke at home (adjusted OR varied between 4 and 6). These results were seen for nicotine as well as for cotinine excretion. Exposure to tobacco smoke in the workplace doubled the risk for the detection of nicotine and cotinine in urine. When other risk factors such as age, sex, social status, community size, season of urine collection, and the consumption of food containing nicotine such as potatoes, cabbage, tea were included, the effect estimates for tobacco smoke exposure remained unchanged. A new federal bill to diminish environmental tobacco smoke (ETS) exposure in the workplace was recently passed in Germany, but protection of nonsmokers from smoking family members at home needs more attention.

Gender differences in the relationship between periodontal disease, tooth loss, and atherosclerosis

BACKGROUND AND PURPOSE

Males carry a disproportionate burden of cardiovascular disease. Because males also bear a higher burden of periodontal disease, we investigated the existence of gender differences in the postulated relationship between periodontal infections, tooth loss, and subclinical atherosclerosis.

METHODS

A total of 1710 randomly enrolled participants between the ages of 45 and 75 with no history of myocardial infarction or stroke received a clinical periodontal examination, carotid scan using high-resolution B-mode ultrasound, and extensive measurements for conventional cardiovascular risk factors (age, education, smoking, alcohol, body mass index, diabetes, systolic blood pressure, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and triglycerides) as well as markers of healthy lifestyle and social network.

RESULTS

In both genders, measures of current and long-term periodontitis worsened as tooth loss increased. In males but not females, an approximately 10% difference in carotid artery plaque prevalence was observed between the lowest and highest tertiles of tooth loss (P<0.05) and long-term periodontitis (P=0.05) after multivariate adjustment. Similar patterns were observed for intima-media thickness. The influence of gender on carotid artery plaque prevalence was most evident among the younger age group (<59 years). Between genders, carotid plaque prevalence differed by 10%, 15%, and 25% across increasing levels of tooth loss, and by 5%, 15%, and 25% across increasing levels of long-term periodontitis.

CONCLUSIONS

Our data suggest that tooth loss and long-term periodontitis are related to subclinical atherosclerosis in men but not women. Gender variations in cardiovascular morbidity or mortality may be explained partly by the differential contributions of novel risk factors across genders.

Vitamin C supplementation decreases oxidative stress biomarker f2-isoprostanes in plasma of nonsmokers exposed to environmental tobacco smoke

Exposure to environmental tobacco smoke (ETS) has been linked to increased risk of lung cancer and cardiovascular diseases in nonsmokers. Current research suggests that some of these diseases are associated with elevated oxidative stress. We investigated the effect of antioxidant (AO) intervention on the lipid peroxidation biomarker F2-isoprostanes (F2-IsoPs), an index of oxidative stress, in plasma of nonsmokers exposed to ETS (passive smokers). We measured free F2-IsoP concentrations in plasma of 67 passive smokers at baseline and after 2 mo of daily intervention with AOs or placebo. The study subjects (47 females, 20 males; mean age 46 +/-15) were randomized into one of three treatment groups: vitamin C, "mixture" (vitamin C, vitamin E, and a-lipoic-acid), and placebo. Investigated confounders included plasma baseline AO levels, lipid and total cholesterol profiles, transferrin saturation, and C-reactive protein. Plasma F2IsoP concentrations of subjects in the vitamin C and mixture groups decreased significantly by 17.2 pmol/l (P = 0.0105) and 19.2 pmol/l (P = 0.0083) when compared with the placebo group (11.4% and 12.7%, respectively). Daily AO supplementation (especially with vitamin C) decreases this oxidative stress biomarker in passive smokers. This finding might be of importance for the prevention of ETS-associated adverse health effects in nonsmokers.

Parental smoking and childhood cancer: results from the United Kingdom Childhood Cancer Study

There are strong a priori reasons for considering parental smoking behaviour as a risk factor for childhood cancer but case - control studies have found relative risks of mostly only just above one. To investigate this further, self-reported smoking habits in parents of 3838 children with cancer and 7629 control children included in the United Kingdom Childhood Cancer Study (UKCCS) were analysed. Separate analyses were performed for four major groups (leukaemia, lymphoma, central nervous system tumours and other solid tumours) and more detailed diagnostic subgroups by logistic regression. In the four major groups, after adjustment for parental age and deprivation there were nonsignificant trends of increasing risk with number of cigarettes smoked for paternal preconception smoking and nonsignificant trends of decreasing risk for maternal preconception smoking (all P-values for trend >0.05). Among the diagnostic subgroups, a statistically significant increased risk of developing hepatoblastoma was found in children whose mothers smoked preconceptionally (OR=2.68, P=0.02) and strongest (relative to neither parent smoking) for both parents smoking (OR=4.74, P=0.003). This could be a chance result arising from multiple subgroup analysis. Statistically significant negative trends were found for maternal smoking during pregnancy for all diagnoses together (P<0.001) and for most individual groups, but there was evidence of under-reporting of smoking by case mothers. In conclusion, the UKCCS does not provide significant evidence that parental smoking is a risk factor for any of the major groups of childhood cancers.

Genetic variation in CYP2A6-mediated nicotine metabolism alters smoking behavior

Approximately 50% of the initiation of tobacco dependence is genetically influenced, whereas maintenance of dependent smoking behavior and amount smoked have approximately 70% genetic contribution (1-5). Determining the variation in nicotine's inactivation is important because of nicotine's role in producing tobacco dependence and regulating smoking patterns (6-11). The genetically polymorphic CYP2A6 enzyme is responsible for the majority of the metabolic inactivation of nicotine to cotinine (12-14). Both in vitro and in vivo studies have demonstrated considerable interindividual variation in CYP2A6 activity (15-17). CYP2A6 is genetically polymorphic, individuals carrying inactive CYP2A6 alleles have decreased nicotine metabolism, are less likely to become smokers and if they do, they smoke fewer cigarettes per day (13,18,19). The decrease in smoking behavior was confirmed by measuring carbon monoxide (CO, a measure of smoke inhalation) levels, plasma and urine nicotine and cotinine levels, and cigarette counts (13,18,19). A duplication variant in the CYP2A6 gene locus has been identified which increases nicotine inactivation and increases smoking (19). CYP2A6 can also activate tobacco smoke procarcinogens (e.g. NNK, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone); current studies are investigating the role of CYP2A6 in risk for lung cancer. Based on these epidemiologic data it was postulated that inhibition of CYP2A6 activity might be useful in a therapeutic context. Kinetic studies in humans indicated that selective CYP2A6 inhibitors decrease the metabolic removal of nicotine. It was also shown that inhibiting CYP2A6 in vivo (phenocopying, or mimicking the genetic defect) in smokers results in decreased smoking, making nicotine orally bioavailable, and the rerouting of procarcinogens to detoxifying pathways (20-22).

Is the hair nicotine level a more accurate biomarker of environmental tobacco smoke exposure than urine cotinine?

STUDY OBJECTIVE

The aim of this study was to compare the two biomarkers of exposure to environmental tobacco smoke (ETS); urine cotinine and hair nicotine, using questionnaires as the standard.

DESIGN

A cross sectional study of children consecutively admitted to hospital for lower respiratory illnesses during the period of the study.

SETTINGS

Three regional hospitals in the larger Wellington area, New Zealand.

PARTICIPANTS

Children aged 3-27 months and admitted to the above hospitals during August 1997 to October 1998. A total of 322 children provided 297 hair samples and 158 urine samples.

MAIN RESULTS

Hair nicotine levels were better able to discriminate the groups of children according to their household's smoking habits at home (no smokers, smoke only outside the home, smoke inside the house) than urine cotinine (Kruskall-Wallis; chi(2)=142.14, and chi(2)=49.5, respectively (p<0.0001)). Furthermore, hair nicotine levels were more strongly correlated with number of smokers in the house, and the number of cigarettes smoked by parents and other members of the child's households. Hair nicotine was better related to the questionnaire variables of smoking in a multivariate regression model (r(2)=0.55) than urine cotinine (r(2)=0.31).

CONCLUSIONS

In this group of young children, hair nicotine was a more precise biomarker of exposure to ETS than urine cotinine levels, using questionnaire reports as the reference. Both biomarkers indicate that smoking outside the house limits ETS exposure of children but does not eliminate it.

Validation of smoking status in clinical research into inflammatory periodontal disease

BACKGROUND

Tobacco smoking is an accepted risk factor for periodontal disease. Most studies in the periodontal literature rely on reported smoking habits which can be unreliable. This review specifically addresses this problem.

METHODS

Methods of assessing tobacco smoke exposure, variation in individual smoking habits, classification of former/ex-smokers, and validation of abstinence in smoking cessation studies receive attention.

DISCUSSION

Additionally, clinical studies that have examined periodontal health in subjects with validated smoking status are discussed.

Seasonal assessment of environmental tobacco smoke and respirable suspended particle exposures for nonsmokers in Bremen using personal monitoring

The study was designed to determine seasonal differences in personal exposures to respirable suspended particles (RSP) and environmental tobacco smoke (ETS) for nonsmokers in Bremen, Germany. The subjects were office workers, either living and working in smoking locations or living and working in nonsmoking locations. One hundred and twenty four randomly selected nonsmoking subjects collected air samples close to their breathing zone by wearing personal monitors for 24 h or, in some cases, for 7-day periods during the winter of 1999. The investigation was repeated in the summer with 126 subjects, comprised of as many of the studied winter population (89 subjects) as possible. Saliva cotinine analyses were undertaken to verify the nonsmoking status of the subjects. Subjects wore one personal monitor while at work and one while away from the workplace on weekdays, and a third monitor at the weekend. Collected air samples were analysed for RSP, nicotine, 3-ethenylpyridine (3-EP) and ETS particles. The latter were estimated using ultraviolet absorbance (UVPM), fluorescence (FPM) and solanesol (SolPM) measurements. ETS exposure was consistently higher in the winter than in the summer, this pattern being particularly evident for subjects both living and working with smokers. The highest median 24-h time weighted average (TWA) concentrations of ETS particles (SolPM, 25 microg m(-3)) and nicotine (1.3 microg m(-3)) were recorded for subjects performing weekday monitoring during the winter. These were significantly higher than equivalent levels of ETS particles (SolPM, 2.4 microg m(-3)) and nicotine (0.26 microg m(-3)) determined during the summer. There were no appreciable differences between winter and summer percent workplace contributions to median TWA ETS particle and nicotine weekday concentrations, the workplace in Bremen, in general, contributing between 35% and 61% of reported median concentrations. Workers, on average, spent one-third of their time at work during a weekday, indicating that concentrations were either comparable or higher in the workplace than in the home and other locations outside the workplace. Median 24-h weekend ETS particle and nicotine concentrations for smoking locations were not significantly different from equivalent weekday levels during the winter, but were significantly lower during the summer. Based upon median 24-h TWA SolPM and nicotine concentrations for the winter, extrapolated to 1 year's ETS exposure, those subjects both living and working in smoking locations (the most highly exposed group) would potentially inhale 13 cigarette equivalents/year (CEs/y). However, based on a similar extrapolation of summer measurements, the same group of subjects would potentially inhale between 1.3 and 1.9 CEs/y. The most highly exposed subjects in this study, based upon 90th percentile concentrations for those both living and working in smoking locations during the winter, would potentially inhale up to 67 CEs/y in the winter and up to 22 CEs/y in the summer. This clearly demonstrates that seasonal effects should be taken into account in the design and interpretation of ETS exposure studies. Air sampling over a 7-day period was shown to be technically feasible, and subsequent RSP, ETS particle and nicotine levels determined by 7-day monitoring were not found to be significantly different from equivalent levels determined by 24-h monitoring. However, the longer sampling period resulted in the collection of an increased quantity of analytes, which improved the limits of quantitation (LOQ) and allowed a more accurate determination of low level ETS exposure. This was reflected by a reduced percentage of data falling below the LOQ for 7-day monitoring compared with 24-h monitoring. The use of a liquid chromatographic method with tandem mass spectrometric detection for saliva cotinine measurement afforded a greatly improved LOQ and greater accuracy at low concentrations compared with the radioimmunoassay (RIA) method used in previous studies by these authors. In this study, 17 subjects out of 180 tested (9.4%) were found to have saliva cotinine levels exceeding the selected threshold of 25 ng ml(-1) used to discriminate between smokers and nonsmokers.

Selected secondhand smoke research: summary and comment

Secondhand smoke is one of the more controversial public health issues. It is controversial because laws regulating secondhand smoke create conflict between the rights of smokers and non-smokers. The results of secondhand smoke research frequently focus on risk factors in four areas: heart disease, cancer, respiratory disorders, and middle ear discase. While many studies have found hazards in each of these four areas, there is some disagreement regarding the degree and extent of the threat posed by these hazards. Future research should discover more risks associated with secondhand smoke and suggest appropriate educational, medical, legal, and environmental remedies for this problem. Then society can establish prevention programs and enact laws which protect non-smokers, but at the same time infringe as little as possible on the rights of others.

Are patients truthful about their smoking habits? A validation of self-report about smoking cessation with biochemical markers of smoking activity amongst patients with ischaemic heart disease

AIMS

To validate self-report about smoking cessation with biochemical markers of smoking activity amongst patients with ischaemic heart disease.

PATIENTS AND METHODS

Outpatients at the Division of Cardiology, 75 years of age or younger, who had been Hospitalized at Sahlgrenska University Hospital in Göteborg due to an ischaemic event and who consecutively participated in a nurse-monitored routine care programme for secondary prevention, from 6 February 1997 to 5 February 1998. Data concerning smoking habits were collected through interviews. Two chemical markers, cotinine in plasma and carbon monoxide (CO) in expired air, validated self-reports concerning smoking cessation.

RESULTS

260 former smokers were validated. In the vast majority of the study population, the anamnestic information concurred with the chemical marker. However, 17 patients had chemical markers that contradicted their self-report with raised CO (n = 6) and/or raised cotinine levels (n = 13) without alternative nicotine delivery.

CONCLUSION

Most patients with coronary artery disease relating information concerning cessation of smoking are truthful. A few patients, however, seem to conceal their smoking. Testing by chemical markers may be questionable for ordinary care but should, however, be included in studies concerning the association between smoking and health.