Relationship between Exhaled Nitric Oxide and Exposure to Low-Level Environmental Tobacco Smoke in Children with Asthma on Inhaled Corticosteroids

Objectives. The relationship between exhaled nitric oxide (FeNO) and asthma severity or control is inconsistent. Active smoking lowers FeNO, but the relationship between passive smoking and FeNO is less clear. Children may be exposed to low-level environmental tobacco smoke (ETS) or thirdhand smoke, even if parents avoid smoking in the presence of their children. Our hypothesis was that FeNO is lower in children with asthma exposed to low-level ETS when compared with those who are not exposed. Methods. Children with stable asthma, 8–18 years of age, on low- or medium-dose inhaled corticosteroids (ICS) were enrolled. Spirometry, Asthma Control Questionnaire (ACQ), FeNO, exhaled breath condensate pH (EBC pH), and EBC ammonia were compared between children with and without ETS exposure as determined by urinary cotinine. Results. Thirty-three subjects were enrolled, of which 10 (30%) had urinary cotinine levels ≥1 ng/ml. There were no significant differences between the two groups in age, sex, BMI percentile, atopy status, FEV₁, EBC pH, or EBC ammonia. Median ACQ was 0.29 (IQR: 0.22–0.57) for those with cotinine levels <1 ng/ml and 0.64 (IQR: 0.57–1.1) for those with cotinine levels of ≥1 ng/ml, p = .02. Median FeNO (ppb) was 23.9 (IQR: 15.2–34.5) for unexposed subjects and 9.6 (IQR: 5.1–15.8) for exposed subjects, p = .008. Conclusions: Children with asthma on low to medium doses of ICS and recent low-level ETS exposure have lower FeNO levels when compared with non-ETS-exposed subjects. Exposure to low-level ETS or thirdhand smoke may be an important variable to consider when interpreting FeNO as a biomarker for airway inflammation.     

Low-level environmental tobacco smoke exposure and inflammatory biomarkers in children with asthma

Objective: The effects of low-level environmental tobacco smoke (ETS) exposure, on asthma control, lung function and inflammatory biomarkers in children with asthma have not been well studied. The objective of the study was to assess ETS exposure in school-age children with asthma whose parents either deny smoking or only smoke outside the home, and to assess the impact of low-level ETS exposure on asthma control, spirometry and inflammatory biomarkers. Methods: Forty patients age 8–18 years with well-controlled, mild-to-moderate persistent asthma treated with either inhaled corticosteroids (ICS) or montelukast were enrolled. Subjects completed an age-appropriate Asthma Control Test and a smoke exposure questionnaire, and exhaled nitric oxide (FeNO), spirometry, urinary cotinine and leukotriene E₄ (LTE₄) were measured. ETS-exposed and unexposed groups were compared. Results: Only one parent reported smoking in the home, yet 28 (70%) subjects had urinary cotinine levels ≥1?ng/ml, suggesting ETS exposure. Seven subjects (18%) had FeNO levels >25parts per billion, six of whom were in the ETS-exposed group. In the ICS-treated subjects, but not in the montelukast-treated subjects, ETS exposure was associated with higher urinary LTE₄, p?=?0.04, but had no effect on asthma control, forced expiratory volume in 1?s or FeNO. Conclusions: A majority of school-age children with persistent asthma may be exposed to ETS, as measured by urinary cotinine, even if their parents insist they don’t smoke in the home. Urinary LTE₄ was higher in the ETS-exposed children treated with ICS, but not in children treated with montelukast.     

Relationship between Exhaled Nitric Oxide and Exposure to Low-Level Environmental Tobacco Smoke in Children with Asthma on Inhaled Corticosteroids

Objectives. The relationship between exhaled nitric oxide (FeNO) and asthma severity or control is inconsistent. Active smoking lowers FeNO, but the relationship between passive smoking and FeNO is less clear. Children may be exposed to low-level environmental tobacco smoke (ETS) or thirdhand smoke, even if parents avoid smoking in the presence of their children. Our hypothesis was that FeNO is lower in children with asthma exposed to low-level ETS when compared with those who are not exposed. Methods. Children with stable asthma, 8-18 years of age, on low- or medium-dose inhaled corticosteroids (ICS) were enrolled. Spirometry, Asthma Control Questionnaire (ACQ), FeNO, exhaled breath condensate pH (EBC pH), and EBC ammonia were compared between children with and without ETS exposure as determined by urinary cotinine. Results. Thirty-three subjects were enrolled, of which 10 (30%) had urinary cotinine levels ≥1 ng/ml. There were no significant differences between the two groups in age, sex, BMI percentile, atopy status, FEV(1), EBC pH, or EBC ammonia. Median ACQ was 0.29 (IQR: 0.22-0.57) for those with cotinine levels <1 ng/ml and 0.64 (IQR: 0.57-1.1) for those with cotinine levels of ≥1 ng/ml, p = .02. Median FeNO (ppb) was 23.9 (IQR: 15.2-34.5) for unexposed subjects and 9.6 (IQR: 5.1-15.8) for exposed subjects, p = .008. Conclusions: Children with asthma on low to medium doses of ICS and recent low-level ETS exposure have lower FeNO levels when compared with non-ETS-exposed subjects. Exposure to low-level ETS or thirdhand smoke may be an important variable to consider when interpreting FeNO as a biomarker for airway inflammation.     

Passive smoking in asthmatic children: effect of a "smoke-free house" measured by urinary cotinine levels.

Environmental tobacco smoke (ETS) decreases pulmonary function and increases both airway reactivity and frequency of child asthma exacerbations. True exposure is related not only to parents smoking and to the number of cigarettes that they smoke, but also to involuntary smoking in public places. The aim of this study was to evaluate, by measuring urinary cotinine levels, the exposure to ETS in asthmatic children and the contribution of unapparent smoke exposure. Twenty asthmatic children (aged 7-12 years) were evaluated on the 1st day (TO) and after a week (T1) in a "smoke-free house." The mean level of urinary cotinine in children was 15.8 +/- 2.7 ng/mg of creatinine at TO and 4.2 +/- 0.6 ng/mg of creatinine at T1 (p < 0.0001). The urinary cotinine concentrations were higher in children living with smoking parents (21.8 +/- 3.4 ng/mg creatinine) compared with children not exposed to parental smoke (6.8 +/- 3.0 ng/mg creatinine; p = 0.017). The number of cigarettes smoked by parents correlates with the urinary cotinine levels (p = 0.005; r = 0.64). Urinary cotinine levels significantly decreased after the avoidance of ETS in children exposed to parental smoke (21.8 +/- 3.4 ng/mg at TO; 5.0 +/- 0.8 ng/mg at T1; p < 0.001) and also in children whose parents declared to be nonsmokers (6.8 +/- 1.2 ng/mg at TO; 3.0 +/- 0.8 ng/mg at T1; p = 0.006). Our data confirm the widespread indirect and undetected tobacco smoke exposure in children with chronic asthma and the relevance of an evaluation with an objective method of the exposure to second-hand smoke.     

Household Smoking and Bronchial Hyperresponsiveness in Children with Asthma

This study investigated whether household environmental tobacco smoke (ETS) exposure is associated with increased bronchial hyperresponsiveness (BHR) in children with asthma. Two hundred forty-nine children, ages 7–11 years, sampled from a larger group with reported asthma or multiple asthma symptoms identified in a community survey in Cape Town, underwent histamine challenge testing and had urinary cotinine measured. Parents were interviewed for information on smoking habits and a variety of covariates. Children with asthma whose mothers smoked had a lower frequency of BHR than asthmatic children of nonsmoking mothers, particularly if the mother smoked ≥15 cigarettes daily. BHR was also less common among children sharing a house with four or more smokers vs. fewer or none. BHR was unrelated to paternal smoking. In contrast, FEV₁ was lower among children whose mothers currently smoked. The findings do not support a mechanism whereby ETS exposure aggravates existing childhood asthma by increasing BHR. This association may be masked, however, by the degree to which mothers of asthmatic children adjust their smoking. The results are consistent with an adverse effect of maternal smoking on lung function in asthmatic children.     

Evaluation of hair cotinine and toxic metal levels in children who were exposed to tobacco smoke

Tobacco or tobacco products (TTP) are harmful because they contain nicotine and some heavy metals. In this study, it was aimed to evaluate whether the responses of parents to questionnaires were compatible with the hair cotinine levels of their children, and to investigate whether exposure to environmental tobacco smoke (ETS) and living conditions increased the levels of cotinine, lead (Pb), arsenic (As), and cadmium (Cd) in the hair samples of the children. Questionnaires were administered to the parents questioning household consumption of TTP and living conditions. Children were grouped as “exposed to ETS” (E‐ETS) and “not exposed to ETS” (NE‐ETS). This grouping was performed through a questionnaire‐based evaluation, and a hair cotinine cut‐off value‐based evaluation. According to the questionnaire‐based evaluation, there were no significant differences in hair Pb, As, and Cd levels between the groups (P‐values: .337, .994, and .825, respectively). The hair cotinine of the E‐ETS group was higher (0.24 ± 0.21 vs 0.22 ± 0.15 ng/mg), but the difference was not statistically significant (P = .317). According to the cotinine evaluation, cotinine, Pb, and As levels were statistically higher in the E‐ETS group (P < .001, <.001, and .036, respectively), but there was no statistical difference between the groups in terms of Cd levels (P = .238). Our results showed that exposure to ETS increased the levels of cotinine, Pb, and As in the hair samples of children, and the questionnaire responses of the parents about their smoking habits might not be compatible with the hair cotinine levels of the children.     

Early smoke exposure is associated with asthma and lung function deficits in adolescents

Objective: Early life tobacco smoke exposure may influence asthma, lung function and lung function growth into adolescence. We aimed to determine the associations between perinatal smoke exposure and asthma and lung function up to 18 years of age. Methods: We prospectively recorded perinatal parental smoking and measured respiratory outcomes at 12 and 18 years in the Melbourne Atopy Cohort Study (MACS), a longitudinal birth cohort. Multiple logistic regression was used to analyse the associations between perinatal smoke exposure and asthma at 12 (n = 370) and 18 years (n = 411). Multiple linear regression was used to investigate the relationship between perinatal smoking and: lung function (12 and 18 years) and lung function growth (between 12 and 18 years). Results: At 18 years, girls exposed to parental smoking during the perinatal period had increased odds of asthma (OR: 3.45, 95%CI: 1.36, 8.77), reduced pre-bronchodilator Forced expiratory volume in one-second (FEV₁) (?272 ml/s; ?438, ?107); FEV₁/ forced vital capacity (FVC) (?0.038; ?0.065, ?0.010); mid expiratory flow (MEF_25-75) (?430 ml/s; ?798, ?61), and reduced post-bronchodilator FEV₁/FVC (?0.028, ?0.053, ?0.004). No associations were found for boys (pre-bronchodilator FEV₁ 26ml/s; ?202, 255; FEV₁/FVC 0.018; ?0.013, 0.049). Conclusions: Perinatal smoke may affect risk of asthma, reduce lung function and lung function growth in adolescence. Girls appear to be more susceptible than boys.     

Pharmacokinetic Predisposition to Nicotine from Environmental Tobacco Smoke: A Risk Factor for Pediatric Asthma

During the last decade several studies have shown that children whose parents smoke have higher rates of asthma. Recently, hair concentrations of cotinine have been shown to reflect systemic exposure to this constituent of smoke in both children and adults. At the present time it is not known, however, why some children exposed to passive smoking have asthma while others, similarly exposed, do not. The present study aimed at verifying whether asthmatic children are different from nonasthmatic children exposed to similar degrees of passive smoking in the way their bodies handle nicotine, a constituent of cigarette smoke. Seventy-eight asthmatic children were compared to 86 control children, all attending a consulting pediatric clinic in Toronto. A questionnaire completed by the parents and children detailed the daily number of cigarettes the child was exposed to and the identity of the smokers. Clinical data were extracted from the patients' charts. Urinary (corrected for creatinine) and hair concentrations of cotinine were measured by radioimmunoassays. The asthmatic and control children were of similar age, gender, and ethnic distribution, parental education, and socioeconomic status. Parents of asthmatic children tended to report a lower daily number of cigarettes (7.4 ± 1.3/day vs. 11.2 ± 2.3/day, p = 0.14), and this report agreed with the trend of urinary cotinine (47.1 ± 9.1 ng/mg vs. 62.6 ±11.5 ng/mg, respectively). Conversely, children with asthma had on average twofold higher concentrations of cotinine in their hair (0.696 ± 0.742 ng/mg) than control children (0.386 ± 0.383) (p = 0.0001). In a similar manner, the hair.urine concentration ratio was significantly higher in children with asthma (0.028 ± 0.002) than in their controls (0.18 ± 0.003) (p = 0.0001). These results suggest that under exposure to similar amounts of nicotine, children with asthma have on average twofold higher systemic exposure to this constituent of cigarette smoke. These data suggest that out of all children passively exposed to environmental tobacco smoke, those who exhibit asthma have a higher systemic exposure to nicotine, possibly due to lower clearance rate. This is the first evidence of pharmacokinetic predisposition to environmental tobacco smoke as an etiological factor in pediatric asthma.     

A controlled trial of an environmental tobacco smoke reduction intervention in low-income children with asthma.

STUDY OBJECTIVES: To determine the effectiveness of a cotinine-feedback, behaviorally based education intervention in reducing environmental tobacco smoke (ETS) exposure and health-care utilization of children with asthma. DESIGN: Randomized controlled trial of educational intervention vs usual care. SETTING: The pediatric pulmonary service of a regional pediatric hospital. PARTICIPANTS: ETS-exposed, Medicaid/Medi-Cal-eligible, predominantly minority children who were 3 to 12 years old and who were seen for asthma in the hospital's emergency, inpatient, and outpatient services departments (n = 87). INTERVENTION: Three nurse-led sessions employing behavior-changing strategies and basic asthma education and that incorporated repeated feedback on the child's urinary cotinine level. MEASUREMENTS: The primary measurements were the urinary cotinine/creatinine ratio (CCR) and the number of acute asthma medical visits. The secondary measurements were number of hospitalizations, smoking restrictions in home, amount smoked, reported exposures of children, and asthma control. RESULTS: The intervention was associated with a significantly lower odds ratio (OR) for more than one acute asthma medical visit in the follow-up year, after adjusting for baseline visits (total visits, 87; OR, 0.32; p = 0.03), and a comparably sized but nonsignificant OR for one or more hospitalization (OR, 0.34; p = 0.14). The follow-up CCR measurement and the determination of whether smoking was prohibited inside the home strongly favored the intervention group (n = 51) (mean difference in CCR adjusted for baseline, -0.38; p = 0.26; n = 51) (60; OR [for proportion of subjects prohibiting smoking], 0.24; p = 0.11; n = 60). CONCLUSIONS: This intervention significantly reduced asthma health-care utilization in ETS-exposed, low-income, minority children. Effects sizes for urine cotinine and proportion prohibiting smoking were moderate to large but not statistically significant, possibly the result of reduced precision due to the loss of patients to active follow-up. Improving ETS reduction interventions and understanding their mechanism of action on asthma outcomes requires further controlled trials that measure ETS exposure and behavioral and disease outcomes concurrently.     

Overcoming Heterogeneity in Pediatric Asthma: Tobacco Smoke and Asthma Characteristics Within Phenotypic Clusters in an African American Cohort

Objective. Asthma in children and adolescents is a heterogeneous syndrome comprised of multiple subgroups with variable disease expression and response to environmental exposures. The goal of this study was to define homogeneous phenotypic clusters within a cohort of children and adolescents with asthma and to determine overall and within-cluster associations between environmental tobacco smoke (ETS) exposure and asthma characteristics. Methods. A combined hierarchical/k-means cluster analysis of principal component variables was used to define phenotypic clusters within a cohort of 6- to 20-year-old urban and largely minority subjects. Results. Among the 154 subjects, phenotypic cluster analysis defined three independent clusters (Cluster 1 [n = 57]; Cluster 2 [n = 33]; Cluster 3 [n = 58]). A small fourth cluster (n = 6) was excluded. Patients in Cluster 1 were predominantly males, with a relative abundance of neutrophils in their nasal washes. Patients in Cluster 2 were predominantly females with high body mass index percentiles and later-onset asthma. Patients in Cluster 3 had higher eosinophil counts in their nasal washes and lower Asthma Control Test? (ACT) scores. Within-cluster regression analysis revealed several significant associations between ETS exposure and phenotypic characteristics that were not present in the overall cohort. ETS exposure was associated with a significant increase in nasal wash neutrophils (beta coefficient = 0.73 [95% confidence interval, CI: 0.11 to 1.35]; p = .023) and a significant decrease in ACT score (?5.17 [?8.42 to ?1.93]; p = .003) within Cluster 1 and a significant reduction in the bronchodilator-induced % change in forced expiratory volume in one second (FEV₁) (?36.32 [?62.18 to ?10.46]; p = .009) within Cluster 3. Conclusions. Clustering techniques defined more homogeneous subgroups, allowing for the detection of otherwise undetectable associations between environmental tobacco smoke exposure and asthma characteristics.     

Pharmacokinetic Predisposition to Nicotine from Environmental Tobacco Smoke: A Risk Factor for Pediatric Asthma

During the last decade several studies have shown that children whose parents smoke have higher rates of asthma. Recently, hair concentrations of cotinine have been shown to reflect systemic exposure to this constituent of smoke in both children and adults. At the present time it is not known, however, why some children exposed to passive smoking have asthma while others, similarly exposed, do not. The present study aimed at verifying whether asthmatic children are different from nonasthmatic children exposed to similar degrees of passive smoking in the way their bodies handle nicotine, a constituent of cigarette smoke. Seventy-eight asthmatic children were compared to 86 control children, all attending a consulting pediatric clinic in Toronto. A questionnaire completed by the parents and children detailed the daily number of cigarettes the child was exposed to and the identity of the smokers. Clinical data were extracted from the patients' charts. Urinary (corrected for creatinine) and hair concentrations of cotinine were measured by radioimmunoassays. The asthmatic and control children were of similar age, gender, and ethnic distribution, parental education, and socioeconomic status. Parents of asthmatic children tended to report a lower daily number of cigarettes (7.4 ± 1.3/day vs. 11.2 ± 2.3/day, p = 0.14), and this report agreed with the trend of urinary cotinine (47.1 ± 9.1 ng/mg vs. 62.6 ±11.5 ng/mg, respectively). Conversely, children with asthma had on average twofold higher concentrations of cotinine in their hair (0.696 ± 0.742 ng/mg) than control children (0.386 ± 0.383) (p = 0.0001). In a similar manner, the hair.urine concentration ratio was significantly higher in children with asthma (0.028 ± 0.002) than in their controls (0.18 ± 0.003) (p = 0.0001). These results suggest that under exposure to similar amounts of nicotine, children with asthma have on average twofold higher systemic exposure to this constituent of cigarette smoke. These data suggest that out of all children passively exposed to environmental tobacco smoke, those who exhibit asthma have a higher systemic exposure to nicotine, possibly due to lower clearance rate. This is the first evidence of pharmacokinetic predisposition to environmental tobacco smoke as an etiological factor in pediatric asthma.     

The role of air nicotine in explaining racial differences in cotinine among tobacco-exposed children

OBJECTIVE: African-American children have higher rates of tobacco-associated morbidity. Few studies have objectively measured racial differences in the exposure of children to tobacco smoke. The objective of this study was to test whether African-American children have higher levels of cotinine compared to white children while accounting for ambient measures of tobacco smoke. SETTING: Community-based sample of asthmatic children (n = 220) enrolled in an environmental tobacco smoke (ETS) reduction trial. PARTICIPANTS: A biracial sample (55% African American) of children with asthma aged 5 to 12 years who were routinely exposed to ETS. MEASUREMENTS: We measured cotinine levels in serum and hair samples at baseline, 6 months, and 12 months. We measured the level of ETS exposure over a 6-month period by placing air nicotine dosimeters in the homes of the children at baseline and at 6-month study visits. RESULTS: African-American children had significantly higher levels of cotinine at all time points in the study. At the 12-month visit, African-American children had higher levels of serum cotinine (1.39 mug/dL vs 0.80 mug/dL, p = 0.001) and hair cotinine (0.28 ng/mg vs 0.08 ng/mg, p < 0.0001) when compared with white children. In a repeated-measures analysis, African-American children had significantly higher levels of serum cotinine (beta = 0.28, p = 0.04) and hair cotinine (beta = 1.40, p < 0.0001) compared with white children. Air nicotine levels and housing volume were independently associated with higher levels of cotinine. CONCLUSIONS: Among children with asthma, African-American children have higher levels of serum and hair cotinine compared with white children.     

Trends in and predictors of second‐hand smoke exposure indexed by cotinine in children in England from 1996 to 2006

Aims To explore trends in and predictors of second‐hand smoke (SHS) exposure in children. To identify whether inequalities in SHS exposure are changing over time. Design Repeated cross‐sectional study with data from eight annual surveys conducted over an 11‐year period from 1996 to 2006. Setting England. Participants Nationally representative samples of children aged 4–15 years living in private households. Measurements Saliva cotinine (4–15‐year‐olds), current smoking status (8–15‐year‐olds), smoking status of parents and carers, smoking in the home, socio‐demographic variables. Findings The most important predictors of SHS exposure were modifiable factors—whether people smoke in the house on most days, whether the parents smoke and whether the children are looked after by carers who smoke. Children from more deprived households were more exposed and this remained the case even after parental smoking status has been controlled for. Exposure over time has fallen markedly among children (59% decline over 11 years in geometric mean cotinine), with the most marked decline observed in the period immediately preceding smoke‐free legislation. Declines in exposure have generally been greater in children most exposed at the outset. For example, in children whose parents both smoke, median cotinine declined annually by 0.115 ng/ml compared with 0.019 ng/ml where neither parent smokes (P < 0.05). Conclusions In the 11 years leading up to smoke‐free legislation in England, the overall level of SHS exposure in children as well as absolute inequalities in exposure have been declining. Further efforts to encourage parents and carers to quit and to avoid smoking in the home would benefit child health.     

Parental smoking and lung function: misclassification due to background exposure to passive smoking

We evaluated the role played by background exposure (i.e. exposure to Environmental Tobacco Smoke, ETS, from sources other than parental smoking) when evaluating the effect of parental smoking on lung function of adolescents. We performed a cross-sectional survey (937 adolescents) in the Lazio Region. Data were collected by a questionnaire, lung function tests and urinary cotinine to creatinine ratios (CCR) were measured. We found that 62.1% of subjects were exposed to current parental smoke. Among the 355 adolescents not exposed to parental smoke, a total of 92 (25.9%) had CCR levels greater than the median value of the distribution (17.3 ng/mg). Subjects with smoking parents had higher FVC and significant lower FEV(1)/FVC ratios than subjects without smoking parents. When "Background" ETS exposure was removed from the unexposed group by separately studying those without parental exposure but with CCR>17.3, results showed a reduction in lung function due to parental smoking which is greater compared to the previous model. Our study adds further evidence regarding the detrimental effect of ETS on lung function of adolescents. Negative results on the effect of parental smoking on lung function should be revisited if background exposure has not been considered in the analysis.     

Household Smoking and Bronchial Hyperresponsiveness in Children with Asthma

This study investigated whether household environmental tobacco smoke (ETS) exposure is associated with increased bronchial hyperresponsiveness (BHR) in children with asthma. Two hundred forty-nine children, ages 7-11 years, sampled from a larger group with reported asthma or multiple asthma symptoms identified in a community survey in Cape Town, underwent histamine challenge testing and had urinary cotinine measured. Parents were interviewed for information on smoking habits and a variety of covariates. Children with asthma whose mothers smoked had a lower frequency of BHR than asthmatic children of nonsmoking mothers, particularly if the mother smoked ≥15 cigarettes daily. BHR was also less common among children sharing a house with four or more smokers vs. fewer or none. BHR was unrelated to paternal smoking. In contrast, FEV₁ was lower among children whose mothers currently smoked. The findings do not support a mechanism whereby ETS exposure aggravates existing childhood asthma by increasing BHR. This association may be masked, however, by the degree to which mothers of asthmatic children adjust their smoking. The results are consistent with an adverse effect of maternal smoking on lung function in asthmatic children.     

Changes in environmental tobacco smoke (ETS) exposure over a 20-year period: cross-sectional and longitudinal analyses

Aims   To examine long-term changes in environmental tobacco smoke (ETS) exposure in British men between 1978 and 2000, using serum cotinine.
Design   Prospective cohort: British Regional Heart Study.
Setting   General practices in 24 towns in England, Wales and Scotland.
Participants   Non-smoking men: 2125 studied at baseline [questionnaire (Q1): 1978–80, aged 40–59 years], 3046 studied 20 years later (Q20: 1998–2000, aged 60–79 years) and 1208 studied at both times. Non-smokers were men reporting no current smoking with cotinine < 15 ng/ml at Q1 and/or Q20.
Measurements   Serum cotinine to assess ETS exposure.
Findings   In cross-sectional analysis, geometric mean cotinine level declined from 1.36 ng/ml [95% confidence interval (CI): 1.31, 1.42] at Q1 to 0.19 ng/ml (95% CI: 0.18, 0.19) at Q20. The prevalence of cotinine levels ≤ 0.7 ng/ml [associated with low coronary heart disease (CHD) risk] rose from 27.1% at Q1 to 83.3% at Q20. Manual social class and northern region of residence were associated with higher mean cotinine levels both at Q1 and Q20; older age was associated with lower cotinine level at Q20 only. Among 1208 persistent non-smokers, cotinine fell by 1.47 ng/ml (95% CI: 1.37, 1.57), 86% decline. Absolute falls in cotinine were greater in manual occupational groups, in the Midlands and Scotland compared to southern England, although percentage decline was very similar across groups.
Conclusions   A marked decline in ETS exposure occurred in Britain between 1978 and 2000, which is likely to have reduced ETS-related disease risks appreciably before the introduction of legislation banning smoking in public places.     

Determination of environmental tobacco smoke in primary school children with urine cotinine measurements

Environmental tobacco smoke (ETS) has been regarded as one of the most important public health issues. It has been estimated that approximately 75% of Turkish children are exposed to ETS. In this study the parental smoking habits were determined. Then, the relationship between parent-reported estimates of children's exposure to ETS in the home and children's urinary cotinine levels was examined. According to the reports of parents, 57.8% of the fathers and 23.3% of the mothers were current smokers, 69.8% of the children came from homes with smokers, and 53.4% had daily exposure to ETS. Urinary cotinine levels were significantly higher in the exposed group than the nonexposed group. This data showed that ETS exposure was prevalent and a combination of a parent-report and a biological measures is suggested as the most informative estimate of ETS exposure in children.     

Association between Prenatal and Postnatal Tobacco Smoke Exposure and Allergies in Young Children

Background. Many studies have shown a positive association between environmental tobacco smoke (ETS) exposure and allergic disorders, whereas epidemiological evidence of the effect of maternal smoking during pregnancy on allergic diseases is inconsistent. We investigated the independent and joint effects of in utero exposure to maternal smoking and postnatal ETS exposure at home on allergic disorders among Japanese children. Methods. Study subjects were 1951 children aged 3 years. Data on maternal smoking during pregnancy and postnatal exposure to ETS at home, allergic symptoms, and potential confounders were collected through the use of a questionnaire. Outcomes were defined according to the criteria of the International Study of Asthma and Allergies in Childhood (ISAAC). Results. The prevalence values of symptoms of wheeze, asthma, and eczema in the previous 12 months were 22.0%, 8.8%, and 17.2%, respectively. We found that postnatal ETS exposure at home in the absence of in utero exposure to maternal smoking was associated with a higher prevalence of wheeze (adjusted odds ratio (OR) = 1.30, 95% confidence interval (CI): 1.01–1.67). In contrast, in utero exposure without subsequent postnatal ETS exposure at home or exposure to postnatal ETS at home in addition to in utero exposure to maternal smoking was not associated with the prevalence of wheeze. No measurable associations were observed between fetal, postnatal, or joint exposure and the prevalence of asthma or eczema. Conclusions. Data from this study indicate that ETS at home may be associated with a higher prevalence of wheeze among young Japanese children.     

Does passive smoke exposure trigger acute asthma attack in children?

The relationship between asthma and passive smoking has been well established. However, it is still not clear whether an acute asthma attack can be induced by acute smoke exposure. The specific aims of this study were: 1- To assess the degree of smoke exposure through urinary cotinine levels in asthmatic children during and 4 weeks after asthma attacks and, 2- To evaluate the reliability of parental questionnaires in asthmatic children by comparing the data obtained from cotinine measurements and parental reports. Thirty-two consecutive asthmatic children who were admitted to the emergency clinic were included in the study. Parents were asked to complete a questionnaire about their smoking habits and housing conditions. Urinary cotinine and creatinine levels were measured in children during and 4 weeks after the acute asthma attack. The mean age of the patients was 5.7 +/- 3.2 years. The mean attack rate was 3.5 +/- 3.8 per year. Thirty-eight percent of the patients were taking no preventive treatment. In 80 % of patients, urinary cotinine and creatinine ratios (CCR) were significantly above the non-exposed, non-smoker levels. However, CCR levels during acute asthma attacks were not higher than those measured 4 weeks after the acute attack (314.6 +/- 299.1 vs. 203.8 +/- 165.2 ng/mg respectively, p > 0.05). Although parental reports of passive smoke exposure was 71 %, CCR levels revealed that 81 % and 97 % of children were exposed to passive smoke during acute attacks and asymptomatic periods, respectively. In conclusion, although the proportion of children with acute asthma attacks who were exposed to passive smoking was high, the degree of passive smoke exposure was not higher during acute attacks. Parental questionnaires were found to be unreliable in reporting passive smoke exposure in asthmatic children during acute attacks.     

Environmental tobacco smoke may induce early lung damage in healthy male adolescents

STUDY OBJECTIVE: Childhood exposure to environmental tobacco smoke (ETS) adversely affects dynamic spirometric indexes as a result of combined early life (including in utero) and current exposure to parental smoking. The aim of our study was to investigate the effect of ETS on lung function and to identify the most sensitive functional parameter for evaluating lung damage. DESIGN: Cross-sectional survey. SETTING: Health survey on secondary school children. SUBJECTS: Eighty adolescents boys (mean age +/- SD, 16 +/- 1 years) classified in three groups: 21 smokers, 30 nonsmokers, and 29 passive smokers. MEASUREMENTS: Standardized questionnaire on the smoking habits of the subjects and their parents; assay of urinary cotinine level and measurement of the cotinine/creatine ratio (CCR); and lung function tests, including measurements of lung volumes, spirometric dynamic parameters, and the single-breath diffusing capacity of the lung for carbon monoxide (DLCO). RESULTS: Passive smokers presented a higher residual volume than nonsmokers, and a lower maximal expiratory flow at 25% of FVC (MEF(25)) and DLCO. Passive smokers whose mothers had smoked during pregnancy had significantly lower MEF(25) percentage, DLCO, carbon monoxide transfer coefficient, and diffusion capacity of the alveolar-capillary membrane (DM) values than did passive smokers whose mothers had given up smoking during pregnancy. Nevertheless, the MEF(25) and DM values of subjects with mothers who had given up smoking during pregnancy were lower than those observed in nonsmokers (p < 0.05), suggesting a negative effect of passive smoking independent of the mother's smoking habit during pregnancy. A statistically significant, negative correlation was found between CCR and DLCO in smokers (r = - 0.63, p < 0.01) and in passive smokers (r = - 0.91, p < 0.001), but not in nonsmokers (r = 0.26, p = not significant), suggesting a dose-effect relationship. CONCLUSIONS: Current exposure to ETS in healthy male adolescents is associated with lung function impairment independently of the effects of maternal smoking during pregnancy. More information may be obtained from determining static lung volumes and DLCO.