Association between parents' smoking status and tobacco exposure in school-age children: assessment using major urine biomarkers

Children are at risk of exposure to secondhand smoke. We aimed to evaluate the extent of their exposure to it in relation to their parents' smoking status by using biomarkers relevant to smoking. We evaluated 847 school-age children (6-12 years) who lived with their parents, using data from the Korea National Health and Nutrition Examination Survey 2016-2018. Secondhand smoke exposure in children of non-smoking and smoking parents was assessed by measuring urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and cotinine concentrations. Overall, the parents of 482 (55.1%) children smoked and those of 392 (44.9%) children did not smoke. After adjusting for covariates, significantly higher concentrations of NNAL (β = 0.482, standard error [S.E.] = 0.065, P < 0.001) and cotinine (β = 0.472, S.E. = 0.06, P < 0.001) were found in children of smoking parents than in children of non-smoking parents. Children of parents who smoked a higher number of cigarettes showed higher NNAL and cotinine concentrations than children of non-smoking parents. Children with both parents who smoked showed the highest NNAL and cotinine concentrations. Children of smoking parents are at a higher risk of exposure to secondhand smoke. A smoke-free environment must be maintained to protect children from the harmful effects of secondhand smoke. Therefore, comprehensive national anti-smoking policies are required.

Difficult and Severe Asthma in Children

Asthma is the most frequent chronic inflammatory disease of the lower airways affecting children, and it can still be considered a challenge for pediatricians. Although most asthmatic patients are symptom-free with standard treatments, a small percentage of them suffer from uncontrolled persistent asthma. In these children, a multidisciplinary systematic assessment, including comorbidities, treatment-related issues, environmental exposures, and psychosocial factors is needed. The identification of modifiable factors is important to differentiate children with difficult asthma from those with true severe therapy-resistant asthma. Early intervention on modifiable factors for children with difficult asthma allows for better control of asthma without the need for invasive investigation and further escalation of treatment. Otherwise, addressing a correct diagnosis of true severe therapy-resistant asthma avoids diagnostic and therapeutic delays, allowing patients to benefit from using new and advanced biological therapies.

Clinical significance of the bronchodilator response in children with severe asthma

BACKGROUND

Our objective was to determine those characteristics associated with reversibility of airflow obstruction and response to maximal bronchodilation in children with severe asthma through the Severe Asthma Research Program (SARP).

METHODS

We performed a cross-sectional analysis evaluating children ages 6 to 17 years with nonsevere asthma (NSA) and severe asthma (SA). Participants underwent spirometry before and after 180 µg of albuterol to determine reversibility (≥12% increase in FEV₁ ). Participants were then given escalating doses up to 720 µg of albuterol to determine their maximum reversibility.

RESULTS

We evaluated 230 children (n = 129 SA, n = 101 NSA) from five centers across the United States in the SARP I and II cohorts. SA (odds ratio [OR], 2.08, 95% confidence interval [CI], 1.05-4.13), second-hand smoke exposure (OR, 2.81, 95%CI, 1.23-6.43), and fractional exhaled nitric oxide (FeNO; OR, 1.97, 95%CI, 1.35-2.87) were associated with increased odds of airway reversibility after maximal bronchodilation, while higher prebronchodilator (BD) FEV₁ % predicted (OR, 0.91, 95%CI, 0.88-0.94) was associated with decreased odds. In an analysis using the SARP III cohort (n = 186), blood neutrophils, immunoglobulin E (IgE), and FEV₁ % predicted were significantly associated with BD reversibility. In addition, children with BD response have greater healthcare utilization. BD reversibility was associated with reduced lung function at enrollment and 1-year follow-up though less decline in lung function over 1 year compared to those without reversibility.

CONCLUSIONS

Lung function, that is FEV₁ % predicted, is a predictor of BD response in children with asthma. Additionally, smoke exposure, higher FeNO or IgE level, and low peripheral blood neutrophils are associated with a greater likelihood of BD reversibility. BD response can identify a phenotype of pediatric asthma associated with low lung function and poor asthma control.

Provider Counseling About Secondhand Smoke Exposure for Urban Children With Persistent or Poorly Controlled Asthma

Urban children continue to be exposed to secondhand smoke (SHS), and this is particularly concerning for children with asthma. The objective of this study is to describe SHS exposure among urban children with asthma and assess SHS counseling delivered at primary care visits. We interviewed caregivers of 318 children (2-12 years) with persistent asthma at the time of a health care visit and reviewed medical records. We found that one third (32%) of children lived with a caregiver who smoked and that 15% lived with other smokers. Children whose caregivers smoked had the lowest prevalence of home smoking bans compared with homes with other smokers and no smokers (65% vs. 72% vs. 95%, respectively). Overall, 67% of caregivers received some SHS counseling. Providers most often counseled caregiver smokers; counseling occurred less frequently for caregivers in homes with other or no smokers. Further efforts to improve provider SHS counseling for all children with asthma are needed.

Effects of cigarette smoking and nicotine metabolite ratio on leukocyte telomere length

Studies of the effects of smoking on leukocyte telomere length (LTL) using cigarettes smoked per day or pack years smoked (PYS) present limitations. Reported high levels of smoking may not increase toxin exposure levels proportionally. Nicotine metabolism ratio (NMR) predicts total cigarette puff volume and overall exposure based on total N-nitrosamines, is highly reproducible and independent of time since the last cigarette. We hypothesized that smokers with higher NMRs will exhibit increased total puff volume, reflecting efforts to extract more nicotine from their cigarettes and increasing toxin exposure. In addition, higher levels of smoking could cause a gross damage in LTL. The urinary cotinine, 3-OH cotinine and nicotine levels of 147 smokers were analyzed using a LC/MS system Triple-Q6410. LTL and CYP2A6 genotype was determined by PCR in blood samples. We found a significant association between NMR and CYP2A6 genotype. Reduction in LTL was seen in relation to accumulated tobacco consumption and years smoking when we adjusted for age and gender. However, there were no significant differences between NMR values and LTL. In our study the higher exposure was associated with lower number of PYS. Smokers with reduced cigarette consumption may exhibit compensatory smoking behavior that results in no reduced tobacco toxin exposure. Our results suggest that lifetime accumulated smoking exposure could cause a gross damage in LTL rather than NMR or PYS. Nevertheless, a combination of smoking topography (NMR) and consumption (PYS) measures may provide useful information about smoking effects on health outcomes.

Blood cadmium levels are associated with a decline in lung function in males

BACKGROUND

Cadmium exposure was found to cause a decline in lung function among the general population, but these findings were limited to smokers and gender differences were not explored.

OBJECTIVES

To examine the relationship between cadmium and chronic obstructive pulmonary disease (COPD) according to gender and smoking status in Korea.

METHODS

Cross-sectional data from the Korean National Health and Nutrition Examination Survey from 2008 to 2011 were analyzed. COPD was defined by a pre-bronchodilator forced expiratory volume in 1s divided by forced vital capacity of <0.70. A logistic regression model was used to elucidate the association between blood cadmium levels and COPD according to gender and smoking status.

RESULTS

Among 3861 eligible participants, 3622 were included in the analysis. The prevalence of COPD demonstrated an increasing trend in males (P for trend<0.001), but not in females (P for trend=0.67). After adjusting for covariates, a higher blood cadmium level, but within the normal range, was associated with COPD in males, including those who had never-smoked (P for trend <0.001 and P for trend=0.008). However, a higher blood cadmium level was not significantly associated with COPD in females, including those who had never smoked (P for trend=0.39 and P for trend=0.43).

CONCLUSIONS

A higher blood cadmium level, within the normal range, was associated with COPD in males, including those who had never smoked. However, there was no significant association between blood cadmium levels and COPD in females.

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 E(4) (LTE(4)) 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 LTE(4), 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 LTE(4) was higher in the ETS-exposed children treated with ICS, but not in children treated with montelukast.

The effects of low-level environmental tobacco smoke exposure on pulmonary function tests in preschool children with asthma

OBJECTIVES

Though parents of children with asthma smoke, they often avoid smoking in their homes or near their children, thus limiting exposure. It is not known if such low-level environmental tobacco smoke (ETS) results in measurable exposure or affects lung function. The objectives of this study were to measure urinary cotinine in preschool children with asthma, and to examine the relationship between low-level ETS exposure and pulmonary function tests (PFTs).

METHODS

Preschool children with asthma were enrolled. Parents completed questionnaires on ETS exposure and asthma control, urinary cotinine concentrations were measured and PFTs were compared between subjects with and without recent ETS exposure.

RESULTS

Forty one subjects were enrolled. All parents denied smoking in their home within the last 2 weeks, but 14 (34%) parents admitted to smoking outside their homes or away from their children. Fifteen (37%; 95%CI: 23-53) of the children had urinary cotinine levels ≥1 ng/ml, of which seven (17%; 95%CI: 8-32) had levels ≥5 ng/ml. FEV1 and FEV0.5 were lower in subjects with a urinary cotinine level ≥5 ng/ml as compared to those with levels <1 ng/ml or between 1 and 5 ng/ml; both at baseline and after inhalation of albuterol. Five of seven subjects with urinary cotinine levels ≥5 ng/ml had FEV0.5 less than 65% of predicted values. There were no significant differences in IOS measures.

CONCLUSIONS

Despite parental denial of smoking near their children, preschool children may be exposed to ETS. Such low-level ETS exposure may affect lung function, possibly in a dose-dependent manner.

Secondhand smoke exposure is associated with proteinuria in children with chronic kidney disease

BACKGROUND

In adults with chronic kidney disease (CKD), cigarette smoking is associated with an increased risk for CKD progression and transplant failure. In children, secondhand smoke (SHS) exposure has been associated with elevated blood pressure. There are no studies on the prevalence and effect of SHS exposure in CKD.

METHODS

Subjects were enrolled in the Chronic Kidney Disease in Children (CKiD) Study, an observational cohort of 366 children aged 1 to 16 years with CKD. Secondhand smoke exposure was obtained via questionnaire. SHS exposure was also determined based on urine cotinine (Ucot) measurements (1 ng/mL ≤ Ucot < 75 ng/mL). The cross-sectional association of SHS exposure with proteinuria was assessed.

RESULTS

Using Ucot, 22 % of subjects were exposed to SHS. SHS exposure was significantly associated with lower maternal education and African American race, and a greater prevalence of nephrotic range proteinuria and left ventricular hypertrophy. In a multivariate model (including sex, age, race, maternal education, income level, private insurance status, abnormal birth history and CKD diagnosis), the prevalence odds of nephrotic range proteinuria was 2.64, (95 % confidence interval 1.08, 6.42) higher in children exposed to SHS compared to those unexposed.

CONCLUSIONS

In our cohort of children with CKD, SHS exposure was common (22 %) and independently associated with nephrotic range proteinuria. Exposure to SHS may be an important factor to consider in CKD progression.

Association of time-location patterns with urinary cotinine among asthmatic children under household environmental tobacco smoke exposure

INTRODUCTION

Environmental tobacco smoke (ETS) is a hazardous component of indoor air, and may increase the risk of respiratory diseases, atherosclerosis and otitis media in children. In this study, we explored the relationship between time inside the house, ETS exposure and urinary cotinine level, and also determined the association of time inside the house on asthma phenotypes when children exposed to ETS.

METHODS

A total of 222 asthmatic children and 205 non-asthmatic controls were recruited in the Genetic and Biomarker study for Childhood Asthma (GBCA). Structured questionnaires and time-location pattern questionnaires were administered by face-to-face interview. Urinary cotinine was measured by liquid chromatography tandem mass spectrometry (LC/MS/MS). The level of household ETS exposure was assessed using the cotinine/creatinine ratio (CCR).

RESULTS

In general, urinary cotinine and CCR were higher in subjects exposed to household ETS than those who never had ETS at home. A significant positive relationship was found between average time inside the house and urinary CCR in asthmatic children with current ETS at home (β=0.278, p=0.02). After adjustment for age and gender, average time inside the house was positively related to severe wheeze in asthmatic children with household ETS within 1 month (OR: 1.26, 95%: 1.02-1.64).

CONCLUSIONS

Our study suggests that the major source of ETS exposure for children is due to longer period of exposures among children living with adult smokers at home. Home-smoking restrictions that effectively prevent children from being exposed to ETS would be worthwhile.

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.

Household smoking behavior: effects on indoor air quality and health of urban children with asthma

The goal of the study was to examine the association between biomarkers and environmental measures of second hand smoke (SHS) with caregiver, i.e. parent or legal guardian, report of household smoking behavior and morbidity measures among children with asthma. Baseline data were drawn from a longitudinal intervention for 126 inner city children with asthma, residing with a smoker. Most children met criteria for moderate to severe persistent asthma (63%) versus mild intermittent (20%) or mild persistent (17%). Household smoking behavior and asthma morbidity were compared with child urine cotinine and indoor measures of air quality including fine particulate matter (PM(2.5)) and air nicotine (AN). Kruskal-Wallis, Wilcoxon rank-sum and Spearman rho correlation tests were used to determine the level of association between biomarkers of SHS exposure and household smoking behavior and asthma morbidity. Most children had uncontrolled asthma (62%). The primary household smoker was the child's caregiver (86/126, 68%) of which 66 (77%) were the child's mother. Significantly higher mean PM(2.5), AN and cotinine concentrations were detected in households where the caregiver was the smoker (caregiver smoker: PM(2.5) μg/m(3): 44.16, AN: 1.79 μg/m(3), cotinine: 27.39 ng/ml; caregiver non-smoker: PM(2.5): 28.88 μg/m(3), AN: 0.71 μg/m(3), cotinine:10.78 ng/ml, all P ≤ 0.01). Urine cotinine concentrations trended higher in children who reported 5 or more symptom days within the past 2 weeks (>5 days/past 2 weeks, cotinine: 28.1 ng/ml vs. <5 days/past 2 weeks, cotinine: 16.2 ng/ml; P = 0.08). However, environmental measures of SHS exposures were not associated with asthma symptoms. Urban children with persistent asthma, residing with a smoker are exposed to high levels of SHS predominantly from their primary caregiver. Because cotinine was more strongly associated with asthma symptoms than environmental measures of SHS exposure and is independent of the site of exposure, it remains the gold standard for SHS exposure assessment in children with asthma.

Factors associated with second-hand smoke exposure in young inner-city children with asthma

OBJECTIVES

To examine the association of social and environmental factors with levels of second-hand smoke (SHS) exposure, as measured by salivary cotinine, in young inner-city children with asthma.

METHODS

We used data drawn from a home-based behavioral intervention for young high-risk children with persistent asthma post-emergency department (ED) treatment (N = 198). SHS exposure was measured by salivary cotinine and caregiver reports. Caregiver demographic and psychological functioning, household smoking behavior, and asthma morbidity were compared with child cotinine concentrations. Chi-square and ANOVA tests and multivariate regression models were used to determine the association of cotinine concentrations with household smoking behavior and asthma morbidity.

RESULTS

Over half (53%) of the children had cotinine levels compatible with SHS exposure and mean cotinine concentrations were high at 2.42 ng/ml (SD 3.2). The caregiver was the predominant smoker in the home (57%) and 63% reported a total home smoking ban. Preschool aged children and those with caregivers reporting depressive symptoms and high stress had higher cotinine concentrations than their counterparts. Among children living in a home with a total home smoking ban, younger children had significantly higher mean cotinine concentrations than older children (cotinine: 3-5 year olds, 2.24 ng/ml (SD 3.5); 6-10 year olds, 0.63 ng/ml (SD 1.0); p < .05). In multivariate models, the factors most strongly associated with high child cotinine concentrations were increased number of household smokers (β = 0.24) and younger child age (3-5 years) (β = 0.23; p < .001, R(2) = 0.35).

CONCLUSION

Over half of the young inner-city children with asthma were exposed to SHS, and caregivers are the predominant household smokers. Younger children and children with depressed and stressed caregivers are at significant risk of smoke exposures, even when a household smoking ban is reported. Further advocacy for these high-risk children is needed to help caregivers quit and to mitigate smoke exposure.

Adolescents validly report their exposure to secondhand smoke

OBJECTIVE

This study examined the validity of child-reported exposure to secondhand smoke (SHS) and investigated factors, such as child's age, which might affect accuracy of recall.

STUDY DESIGN AND SETTING

Participants were drawn from a nonprobability sample of 380 families who completed baseline assessment as part of a randomized trial of an SHS reduction intervention conducted in an urban setting in Southern California. Parents and children (aged 8-13 years) retrospectively reported child's exposure to SHS using timeline followback methodology; reports were compared with child's urine cotinine.

RESULTS

Validity coefficients for parents and children were comparable (r=0.58 vs. r=0.53), but parents recalled three times more exposure than children (2.2 vs. 0.8 cigarettes per day; P<0.001). Regression models predicting cotinine indicated that including child in addition to parent reports resulted in better prediction than either alone.

CONCLUSION

When there is a choice, parent reports are preferable over child reports because of decreased underreporting. However, child-reported SHS exposure had adequate validity (r>0.50) and might be appropriate in some situations. Researchers might consider collecting both parent and child reports because each made a unique contribution to the prediction of cotinine.

Motivation to quit smoking among parents of urban children with asthma

OBJECTIVE

To identify factors associated with motivation to quit smoking among parents of urban children with asthma.

METHODS

We analyzed data from parents who smoke and had a child enrolled in the School-Based Asthma Therapy (SBAT) trial. We assessed asthma symptoms, children's cotinine, and parent smoking behaviors. Motivation to quit smoking was assessed by a 10-point continuous measure (1, not at all motivated; 10, very motivated).

RESULTS

209 parents smoked (39% of sample), and children's mean cotinine was 2.48 ng/ml. Motivation to quit was on average 6.9, and 47% of parents scored >or=8 on the scale. Parents who believed their child's asthma was not under good control, and parents who strongly agreed their child's asthma symptoms would decrease if they stop smoking had higher motivation to quit compared to their counterparts (p<.05). In a multivariate analysis, parents who believed their child's asthma was not under control had more than twice the odds of reporting high motivation to quit.

CONCLUSION

Parents' perception of the risks of smoking to their child with asthma is associated with motivation to quit.

PRACTICE IMPLICATIONS

Raising awareness about the effect of smoking and quitting on children's asthma might increase motivation to quit among parents.

Simultaneous and sensitive measurement of nicotine, cotinine, trans-3'-hydroxycotinine and norcotinine in human plasma by liquid chromatography-tandem mass spectrometry

An LC-MS/MS method for the simultaneous quantification of nicotine, cotinine, trans-3'-hydroxycotinine and norcotinine in human plasma was developed and fully validated. Potential endogenous and exogenous interferences were extensively evaluated and limits of quantification were determined by decreasing analyte concentration. Analytical ranges were 1-500 ng/mL for nicotine and cotinine, 5-500 ng/mL for trans-3'-hydroxycotinine and norcotinine. Mean intra- and inter-assay analytical recoveries were between 101.9 and 116.8%, and intra- and inter-assay imprecision were less than 11% RSD for all analytes: parameters were evaluated at three different concentrations across the linear range of the assay. Extraction efficiency was > or = 70% for all analytes. This validated method is useful for the determination of nicotine and metabolites in human plasma to support research on the role of nicotine biomarkers on neuronal systems mediating cognitive and affective processes and to differentiate active, passive and environmental exposure.

Exhaled carbon monoxide screening for environmental tobacco smoke exposure in preanesthetic children

OBJECTIVE

Exposure to environmental tobacco smoke (ETS) is associated with an increased risk of perioperative adverse events in children. The purpose of this study was to evaluate exhaled carbon monoxide (CO) as a preoperative ETS screening tool in children.

METHODS

Five hundred and one children aged 6-15 years were enrolled. The child's guardian completed a questionnaire that surveyed environmental exposures to CO and ETS. A preoperative urine sample was obtained from children who assented and were able to void, and urine cotinine values were measured. Exhaled CO was measured using the EC50-Micro Smokerlyzer (Bedfont Scientific Ltd, UK).

RESULTS

Four hundred and fifty-one subjects completed the study, and urine samples were obtained from 83. 25% of subjects were classified as exposed to ETS based on questionnaire results. Exhaled CO values did not correlate with either the qualitative (questionnaire) or quantitative (urine cotinine) measurements of ETS exposure. Exhaled CO predicted a urine cotinine/creatinine ratio >10 with a sensitivity of 10% and a specificity of 85%.

CONCLUSION

Exhaled CO measured by this device is not a useful preoperative screening tool for ETS exposure in children. Because exhaled CO has been used successfully to monitor ETS exposure in adolescents, we believe that its failure in our population is as a result of the limited ability of small children to perform vital capacity maneuvers in order to provide an adequate endtidal sample.

Screening for environmental tobacco smoke exposure among inner-city children with asthma

OBJECTIVES

The goals were (1) to develop an index measure of environmental tobacco smoke based on parent self-report of smoking behaviors and (2) to determine whether the index score was associated with children's present and future cotinine levels.

METHODS

Data were drawn from a community intervention for inner-city children with persistent asthma (N=226; response rate: 72%). Measures of child salivary cotinine levels and parent self-reported environmental tobacco smoke-related behaviors were obtained at baseline and 7 to 9 months later. To develop the index score, we used a 15-fold cross-validation method, with 70% of our data, that considered combinations of smoke exposure variables and controlled for demographic features. We chose the most parsimonious model that minimized the mean square predictive error. The resulting index score included primary caregiver smoking and home smoking ban status. We validated our model with the remaining 30% of the data. Analysis of variance and multivariate analyses were used to determine the association of the index score with children's cotinine levels.

RESULTS

Fifty-four percent of children with asthma lived with >or=1 smoker, and 51% of caregivers reported a complete home smoking ban. The children's mean baseline cotinine level was 1.55 ng/mL (range: 0.0-21.3 ng/mL). Children's baseline and follow-up cotinine levels increased as scores on the index measure increased. In a linear regression, the index score was significantly positively associated with children's cotinine measurements at baseline and 7 to 9 months later.

CONCLUSION

An index measure with combined information regarding primary caregiver smoking and household smoking restrictions helped to identify children with asthma with the greatest exposure to environmental tobacco smoke and could predict which children would have elevated cotinine levels 7 to 9 months later.

Passive smoking and inflammatory bowel disease: a meta-analysis

OBJECTIVES

Active smoking has a well-documented role in the etiology of inflammatory bowel disease (IBD), but the role of passive smoking has been unclear. This meta-analysis examined the relationship between prenatal smoke exposure and childhood passive smoke exposure and the development of IBD.

METHODS

We searched the MEDLINE and EMBASE databases to identify observational studies regarding the relationship between prenatal and/or childhood passive smoke exposure and the development of Crohn's disease (CD) and/or ulcerative colitis (UC). Pooled odds ratios (OR) were calculated for each relationship.

RESULTS

A total of 534 and 699 potential studies were identified from the MEDLINE and EMBASE databases, respectively, of which 13 met all of our inclusion criteria. Overall, we did not observe a positive relationship between childhood passive smoke exposure and CD (OR 1.10, 95% confidence interval [CI] 0.92-1.30) or UC (OR 1.01, 95% CI 0.85-1.20). Likewise, we did not observe an association between prenatal smoke exposure and CD (OR 1.10, 95% CI 0.67-1.80), or prenatal smoke exposure and UC (OR 1.11, 95% CI 0.63-1.97).

CONCLUSIONS

Our meta-analysis suggests that there is not a strong association between childhood passive smoke exposure and the development of CD. We found no evidence that childhood passive smoke exposure exerts a protective effect against UC, as is the case in active smoke exposure. The heterogeneity among the small number of studies limited the ability to draw conclusions about prenatal smoke exposure.

Associations of glutathione S-transferase P1, M1, and environmental tobacco smoke with wheezing illness in school children

BACKGROUND

Polymorphisms at the glutathione S-transferase (GST) were associated with asthma-related phenotypes. We hypothesized that the GSTP1 and GSTM1 genotypes could modify the effects of household environmental tobacco smoke (ETS) on childhood wheezing illness.

METHODS

We conducted a case-control study comprised of 216 lifetime wheezing children and 185 nonwheezing controls, all of whom were selected from 2524 fourth- to ninth-grade school children in southern Taiwan.

RESULTS

Homozygous GSTP1 Ile-105 was significantly associated with current wheezing (OR = 1.78, 95% CI 1.04-3.12), but insignificantly associated with ever wheezing (OR = 1.26, 95% CI 0.82-1.94). The risks of ever or current wheezing on GSTM1 null genotype were positive but not statistically significant. Although household ETS exposure was not associated with wheezing illness, after excluding subjects having in utero ETS or active smoking habits, the adverse effects of household ETS exposure differed significantly by GSTP1-105 genotypes. In children without any ETS exposure at home, GSTP1 Ile-105 homozygosity was significantly related to increased risks for both ever wheezing (OR = 2.29, 95% CI 1.17-4.49) and current wheezing (OR = 4.86, 95% CI 1.86-12.70). In children with household ETS exposure, the risks of wheezing illness did not increase for those carrying two GSTP1 Ile-105 alleles. Children carrying any GSTP1 Val-105 allele were at a significantly greater risk of both ever and current wheezing when exposed to ETS, with a clear dose-response relationship to the number of smokers at home.

CONCLUSION

Household ETS exposure is a modifiable cause of wheezing illness in a genetically susceptible subpopulation.

Barriers to reducing ETS in the homes of inner-city children with asthma

This study assessed knowledge regarding the harm of environmental tobacco smoke (ETS) exposure and barriers to reducing ETS from the point-of-view of urban parents of asthmatic children. We conducted in-depth interviews with 15 mothers of children with asthma. All parents had good knowledge regarding the harmful effects of ETS. While all children of smoking parents were exposed to ETS, parents described using various strategies to keep ETS away from children. Many parents experienced significant stress in their lives and used smoking to relieve their stress. Barriers to a smoke-free home included stress, addiction, and the use of ineffective strategies to reduce ETS exposure.

Fécondation in vitro et tabac: intérêt de la cotininurie et de l'analyseur de monoxyde de carbone expiré

OBJECTIVE

To study the correlation between expired air carbon (EACO) and urinary cotinine, and to determine the impact of tobacco smoking on in vitro fertilization (IVF) results.

PATIENTS AND METHODS

We studied prospectively 221 patients in our ART center from October 2002 to October 2004: 51 active smokers, 85 passive smokers, and 85 non-smokers. Patients were classified into active, passive smokers, or non-smokers, based on a questionnaire. We measured urinary cotinine and EACO on the embryo transfer day and we recorded the IVF parameters.

RESULTS

Two hundred and twenty-one patients were included. We observed a 17.2% reduction of estradiolemy (P=0.05), a 1.5% reduction of pregnancies (NS), a 7.8% reduction of infants born alive (NS), a 28.5% reduction of twin pregnancies (P=0.06), as well as a 10% increase of miscarriages (NS) in the active smokers in comparison with non-smokers (the same trends were observed between active and passive smokers). EACO and urinary cotinine were well correlated. There was a negative correlation between estradiolemy and urinary cotinine (R=-0.15, P=0.02).

DISCUSSION AND CONCLUSION

Tobacco smoking intensity may be dilatory on IVF results. There is a high correlation between EACO and urinary cotinine. Other larger studies would probably obtain results more statistically significant.

Comparative analysis of the effects of hubble-bubble (Sheesha) and cigarette smoking on respiratory and metabolic parameters in hubble-bubble and cigarette smokers

OBJECTIVES AND BACKGROUND

Hazard of smoking tobacco is believed to be minimized by smoking hubble-bubble (HB) instead of cigarettes. Our aims were to (i) develop an assay for estimating nicotine and cotinine; and (ii) evaluate the effect of smoking on respiratory and metabolic parameters in cigarette and HB smokers.

METHODS

Urine samples were collected from 152 volunteer smokers (75 cigarette and 77 HB) as well as from 16 healthy controls. We optimized an HPLC method for the determination of nicotine and cotinine. Subjects were asked to complete a chronic respiratory symptoms questionnaire and to undergo spirometry. Fasting blood samples were collected for the determination of their lipid profile.

RESULTS

The intra-assay coefficients of variation for nicotine and cotinine were 16.6% and 6.6%, respectively. The mean of cotinine in cigarette smokers (1321.4 ng/mL) was significantly (P = 0.008) higher than the mean cotinine (677.6 ng/mL) in HB smokers. The mean nicotine level in cigarette smokers (1487.3 ng/mL) was significantly (P < 0.0001) higher than the mean nicotine (440.5 ng/mL) in HB smoker. The urinary cotinine and nicotine levels of the control subjects were lower than the detection levels of the assay. The mean high-density lipoprotein cholesterol was lower in cigarette smokers (0.99 mmol/L) compared with HB smoker smokers (1.02 mmol/L) but this was not significant (P = 0.28). Spirometric values were comparable among the three groups but the chronic respiratory symptoms in the smoking groups appeared at an earlier age in the HB smokers compared with the cigarettes smokers (P < 0.05).

CONCLUSION

Smoking HB does not reduce the risk of tobacco exposure and it's potentially harmful metabolites on health.

The effects of exposure to environmental tobacco smoke on pulmonary function in children undergoing anesthesia for minor surgery

BACKGROUND

The objectives of this study were to assess whether children exposed to environmental tobacco smoke (ETS) present for surgery with poorer pulmonary function, and experience a more pronounced deterioration in pulmonary function following anesthesia and surgery, than non-ETS-exposed children.

METHODS

Fifty-four children aged 5-15 years with a history of ETS exposure from one or both parents and 54 children with no such ETS history were included in the study. All participants were presenting for ambulatory surgery and were judged to conform to American Society of Anesthesiology class I or II. Spirometry was performed preoperatively, postoperatively in the recovery ward when the child met criteria for discharge (Aldrete score 8), and before discharge from the day ward.

RESULTS

The ETS-exposed group had a significantly lower mean preoperative peak expiratory flow rate (PEFR) (9.5 points lower percent predicted, 95% confidence interval -18.1 to -1.0, P = 0.03). Although not statistically significant, they also had lower percent predicted baseline mean values of the other spirometric variables that were measured (forced expiratory volume in 1 s -4.5%, P = 0.07; forced vital capacity -4.1%, P = 0.10; forced expiratory flow between 25% and 75%-3.6%, P = 0.44). Pulmonary function tests (PFTs) performed in recovery were between 8% and 14% worse than preoperative values, but the results were similar in the two groups of children. PFTs performed before hospital discharge demonstrated an near-complete recovery to baseline values. Again the pattern was similar in exposed and nonexposed children.

CONCLUSIONS

Environmental tobacco smoke exposure is associated with lower preoperative PEFR values, but does not impact on recovery from anesthesia for healthy children undergoing ambulatory anesthesia.

Do parents of urban children with persistent asthma ban smoking in their homes and cars?

OBJECTIVE

Environmental tobacco smoke (ETS) increases morbidity for children with asthma. One method to reduce children's ETS exposure is to completely ban smoking in the home and car. We sought to evaluate the degree to which urban children with persistent asthma are protected by household and car smoking bans, and to determine whether health care professionals are counseling parents to implement smoking bans.

METHODS

We asked parents of children with asthma to complete an in-person interview including questions about asthma symptoms, smokers in the home, smoking bans (home and car), and the receipt of ETS counseling by health care professionals.

RESULTS

We included 231 children with persistent asthma symptoms (response rate 94%). Nearly half of the children lived with a smoker. Overall, only 64% of households had complete restrictions on smoking in the home and car. Even among the children with severe persistent symptoms, less than two-thirds were protected by a complete smoking ban. Among households with smokers, only 51% had a ban on smoking in the home and 49% in the car. The majority of caregivers had been questioned by health care professionals about home smoke exposure; less were asked about exposure in the car (40%) or given suggestions to decrease the child's exposure (58%).

CONCLUSIONS

To our knowledge this is the first study to establish the prevalence of smoking bans among children with persistent asthma. Many children with asthma, even those with the most severe symptoms, remain exposed to ETS in the home and in cars. Identifying and reducing smoke exposure among these children should be a health care priority.

Uptake of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone by Moldovan children

The evidence of an association between childhood exposure to environmental tobacco smoke (ETS) and an increased risk of lung cancer is inconsistent. However, taking into account the existing association between lung cancer and adulthood ETS exposure, it is plausible that children exposed to ETS also would be at risk of developing lung cancer later in life. In this study, we investigated the uptake by Moldovan children of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) by measuring total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), the sum of the NNK metabolites, NNAL, and its O-glucuronide and N-glucuronide (NNAL-Glucs) in urine. We also measured urinary cotinine and its glucuronide (total cotinine). Total NNAL was detected in 69 of 80 samples, including those that were low in cotinine (<5 ng/mL). The mean+/- SD level of total NNAL (0.09+/- 0.077 pmol/mL) was comparable with those observed in previous studies of children and adults exposed to ETS. Total NNAL correlated with total cotinine (r=0.8, P<0.0001). The mean+/- SD levels of total NNAL and total cotinine were higher in children who were exposed to ETS (0.1+/- 0.08 and 109+/- 126 pmol/mL, respectively) than in those who were classified as unexposed to ETS based on questionnaire data (0.049+/- 0.016 pmol/mL and 0.043+/- 0.040 nmol/mL). The results of this study for the first time show widespread and considerable uptake of nicotine and the tobacco-specific lung carcinogen NNK in Moldovan children. These results should be useful in heightening the awareness of the dangers of smoking and ETS exposure in this eastern European country.

Accuracy of parental and youth reporting of secondhand smoke exposure: the Florida youth cohort study

The accuracy of adolescent and parental reports of youth secondhand smoke exposure has received limited attention in the research literature. Florida Youth Cohort Study participants provided saliva samples during the fifth round of interviews for determination of cotinine levels. After exclusion of admitted or likely youth smokers with cotinine levels>14.7 ng/ml, there were 341 youth ages 13-17 who completed a telephone interview; 304 parents of these participants completed a similar secondhand smoke exposure interview. Adolescents with cotinine levels above the threshold of detection (> 0.10 ng/ml) were considered exposed. Specificity ranged from 87.1-97.8. Positive predictive value, negative predictive value, sensitivity, and kappa values varied considerably by the reporting source (e.g., youth, parent, or a combination of responses), and the age and gender of the youth respondent. Agreement between youth and parent that at least one parent smoked inside the home yielded the best combination of sensitivity (85.0) and specificity (89.8) and was least affected by the age and gender of the youth respondent.

Environmental tobacco smoke exposure in children: parental perception of smokiness at home and other factors associated with urinary cotinine in preschool children

Parental smoking behavior at home and sociodemographic variables may influence exposure to environmental tobacco smoke (ETS) in children. A sample of 115 preschool children aged 3-6 years was enrolled in this study. ETS exposure was evaluated through a questionnaire about parents' smoking behavior and determinations of urinary cotinine -- a biomarker of exposure -- in children. Bivariate and multiple regression analyses were used to evaluate the association between the smoking behavior of each parent at home, sociodemographic factors and cotinine levels in children. The parental perception of smokiness in the home was significantly associated with urinary cotinine in children (r-partial coefficient=0.324; P<0.002). The father's education, mother's smoking status, and day of the week when urine was sampled (Tuesday) were also independently associated with levels of cotinine. These four variables explained 26.4% of the variance in the cotinine levels of children. In designing educational programs to reduce passive smoking among children, it is necessary to take into account those factors related with cotinine levels in children. Our results support the influence of the mothers' smoking status, the fathers' educational level, and the day of the week of sampling on cotinine in children. The perception of parents (smokers and nonsmokers) about the smokiness in the home could also be a useful indicator of the cotinine in children exposed to environmental tobacco smoke in the household.

Do children with asthma and their parents agree on household ETS exposure? Implications for asthma management

The adverse consequences of passive smoking have spurred efforts to reduce environmental tobacco smoke (ETS) exposure among children, particularly in the home. For children with asthma, teaching them to avoid tobacco smoke at home is an important element of patient self-management. This strategy assumes that children can accurately assess household smoking behaviors and the level of their own exposure in the home. This study compared child and parental assessments of household smoking behaviors in an urban, low-income and largely ethnic minority sample of asthmatic children and their parents. While there was general parent-child agreement on the smoking status of household members, there was less agreement on duration of household smoking and the child's exposure to ETS. Objective validation measures (cotinine, nicotine) suggest that parents were better able than their children to assess hours of indoor smoking. Children's assessment of the extent of exposure to ETS may be problematic, with important implications for asthma patient self-management efforts.

Relationship between environmental tobacco smoke and urinary cotinine levels in passive smokers at their residence

Studies of the health effects of environmental tobacco smoke (ETS) using measured air concentrations are subject to bias. Cotinine, a nicotine metabolite detected in urine, has been recommended as a quantitative measure of nicotine intake and thus as a marker for ETS exposure in humans. The aim of this study was to correlate home indoor ETS levels with passive smokers' urinary cotinine levels. The urinary cotinine concentrations of 57 non-smoking women who spend >19 h a day at home and the nicotine levels in their living room air were measured over a period of 24 h. Nicotine and urinary cotinine levels were analyzed using GC/MS and HPLC/UV, respectively. In addition, information was collected regarding the smoking habits of the subjects' families. A significant correlation was found between the nicotine levels in indoor air and the urinary cotinine to creatinine ratio of the passive smokers. The smoking habits of the subjects' family members were also correlated to the urinary cotinine levels of the passive smokers.

Repeated validation of parental self-reported smoking during pregnancy and infancy: a prospective cohort study of infants at high risk for allergy development

Exposure to environmental tobacco smoke (ETS) during fetal life and infancy is closely related to the smoking habits of the parents. Estimates of exposure to ETS require valid and detailed information on changes in cigarette smoking over time. The objective was to test the validity of self-reported smoking among parents during pregnancy and early childhood in a cohort of children at high risk for allergy development by measurement of exhaled carbon monoxide (CO). The cohort comprised 117 families enrolled from the general population of pregnant women at admission to antenatal care. Data on parental tobacco smoking were obtained by interview and exhaled CO was measured (Micro-Smokerlyzer(R)) in parents twice during pregnancy and when the child was 6 and 18 months old. The median (range) exhaled CO levels were 3 (0-10) parts per million (ppm) for non-smokers and 15 (1-39) ppm for smokers (P < 0.0005). A receiver operating characteristic (ROC) analysis was performed at each examination. The areas under the ROC curve were high for both mothers (between 0.88 and 0.99) and fathers (between 0.87 and 0.89), indicating exhaled CO as a good diagnostic tool for determining smoking status. Comparing the ROC areas obtained for mothers from late pregnancy and during infancy with the area from early pregnancy showed no statistical differences (P = 0.21, 0.43 and 0.44 respectively) and the same was true for fathers during infancy (P = 0.81). The level of 8 ppm was used as the cut-off between smokers and non-smokers, based on data from a pilot study. Using CO as a diagnostic tool for smoker status showed very high specificity (between 97 and 100%), indicating that very few persons claiming to be non-smokers had CO levels higher than 8 ppm. In conclusion, the validity of interview-obtained self-reported smoking among parents during pregnancy and early childhood was high. Repeated interviews and CO measurements in a prospective study design did not change the validity, indicating a low risk of information bias. A structured interview combined with measurement of exhaled CO is a valid and reliable method for estimating ETS exposure to the fetus and young infant.

Increased respiratory symptoms following surgery in children exposed to environmental tobacco smoke

OBJECTIVE

The aim of this study was to determine if children exposed to environmental tobacco smoke (ETS) via parental smoking (ETS+) developed more respiratory symptoms resulting in longer recovery times following surgical outpatient procedures compared with children of nonsmoking parents (ETS-).

METHODS

One hundred and forty six children (4.9 +/- 3 years) undergoing inguinal hernia repair were prospectively studied. Parental smoking behaviour was determined by survey and urine analysis. Seven respiratory symptoms were evaluated during induction and emergence from anaesthesia and during the recovery room (RR) stay.

RESULTS

Fifty-seven (39%) families admitted a smoking history while 89 (61%) denied it. This strongly correlated with the cotinine/creatinine ratio (Pearson correlation coefficient = 0.76; P = 0.01). ETS exposure was associated with an increased frequency of RR symptoms (ETS+: 56%; ETS-: 31%; P = 0.007).

CONCLUSIONS

In children undergoing general anaesthesia for inguinal hernia repair, ETS exposure was associated with an increased frequency of respiratory symptoms during emergence from anaesthesia and during postoperative recovery.

Questionnaire or objective assessment for studying exposure to tobacco smoke among asthmatic and healthy children: The French VESTA Study

BACKGROUND

The underreporting of environmental tobacco smoke (ETS) exposure by parents of study children may depend on the instrument used and population studied, underlining the need for questionnaire validation in specific study settings. This study explores the validity of parent-reported ETS exposure in a French multicenter study on asthma.

METHODS

The study population was composed of 313 children ages 4 to 14 years. Exposure to ETS was evaluated both by questionnaires on recent ETS exposure and by assessment of urinary cotinine by an enzyme immunoassay.

RESULTS

According to parents' reports, about one-third of children were exposed to ETS within the past 2 days before cotinine measurement, and on average 14.9 +/- 15.4 cigarette-equivalent were smoked in their homes. The mean urinary cotinine was 435 +/- 530 nmol/mol creatinine and increased with the reported number of cigarette-equivalents smoked at home but it did not differ between children registered as being exposed to 1-10 cigarettes and children registered as unexposed. Agreement between questionnaire and urinary cotinine was moderate to poor according to our correlation coefficient (0.22) and kappa coefficient (0.09).

CONCLUSION

These results show that our questionnaire is not discriminating enough to distinguish between nonexposure and mild exposure, but reveals gradients of higher exposure.

Household smoking behavior and ETS exposure among children with asthma in low-income, minority households

Environmental tobacco smoke (ETS) exposure was measured among 242 children with asthma who live in homes where at least one person smokes. Subjects were identified through clinics, schools, community agencies, and hospitals serving low-income, medically underserved communities in Los Angeles. Parents were surveyed about smoking behaviors in the household, children's ETS exposure, and attitudes towards smoking and smoking behavior change. Validation measures included urine cotinine for the child with asthma and passive air nicotine monitors placed in the subjects' homes. Overall reported levels of household smoking and ETS exposure were low, with a significant amount of household smoking taking place outside rather than inside the home. Over 47% of the respondents reported absolute restrictions against smoking in the home, and these restrictions were associated with lower reported levels of smoking, ETS exposure, and air nicotine and urine cotinine concentrations.

Children's exposure to environmental tobacco smoke in the home: comparison of urine cotinine and parental reports

The authors examined the relationship between parent-reported estimates of children's exposure to environmental tobacco smoke (ETS) in the home and children's urinary cotinine levels. Data were collected from a largely ethnic minority, low-income, urban sample of households in which a child had asthma and at least 1 household member smoked. Information about level of household smoking restriction, parental smoking status, and number of cigarettes smoked per day accounted for approximately 45% of the variance in cotinine concentration. Detailed information about the duration of household smoking or children's ETS exposure added no additional significant information. Questionnaires eliciting detailed information about smoking habits and children's ETS exposure may be no better at predicting children's urinary cotinine levels than simpler surveys that inquire about smoking restrictions in the home, parental smoking status, and number of cigarettes smoked at home per day.

Involuntary smoking and asthma severity in children: data from the Third National Health and Nutrition Examination Survey

STUDY OBJECTIVES

We sought to determine the indicators of asthma severity among children in the United States with high and low levels of tobacco smoke exposure.

DESIGN

Cross-sectional study.

SETTING

Nationally representative survey of participants in the Third National Health and Nutrition Examination Survey (from 1988 to 1994).

PARTICIPANTS

Five hundred twenty-three children with physician-diagnosed asthma.

MEASUREMENTS AND RESULTS

We stratified the study participants into tertiles on the basis of serum levels of cotinine (a metabolite of nicotine that indicates tobacco smoke exposure). We used logistic and linear regression modeling, adjusting for known covariates, to determine the effect of high environmental tobacco smoke exposure on the following outcomes: asthma severity (determined using reported symptom and respiratory illness frequency); lung function; physician visits; and school absence. Among our study sample, 78.6% of children had mild asthma, 6.8% of children had moderate asthma, and 14.6% of children had severe asthma. Asthmatic children with high levels of smoke exposure, compared with those with low levels of exposure, were more likely to have moderate or severe asthma (odds ratio, 2.7 95% confidence interval [CI], 1.1 to 6.8) and decreased lung function, with a mean FEV(1) decrement of 213 mL or 8.1% (95% CI, -14.7 to -3.5).

CONCLUSIONS

Involuntary smoke exposure is associated with increased asthma severity and worsened lung function in a nationally representative group of US children with asthma.

HPTLC screening assay for urinary cotinine as biomarker of environmental tobacco smoke exposure among male adolescents

For selective screening determination of urinary cotinine, i.e. (S)-1-methyl-5-(3-pyridyl)-2-pyrrolidinone, the major metabolite of nicotine, the high-performance thin-layer chromatographic (HPTLC) method have been proposed. Prior the final HPTLC analysis the procedure required a solid-phase extraction (SPE) of cotinine from collected urine samples with 1-methyl-2-pyrrolidinone as an internal standard. Densitometrical quantitation of cotinine on the chromatograms have been performed with a 16-grayscale scanner using the specialized software implemented on a desktop microcomputer. The lower detection limit of cotinine was 6 microg/l allowing the method to be applied for the measurement a concentration of this compound in urine samples collected from 35 elementary schoolboys exposed on both moderate and/or significant ETS. The mean recovery of cotinine from urine samples was 93%. The mean intra-day accuracy for the analysis of cotinine in range 6-750 microg/l. including four paralell measurements, was 2.9 %. The results of cotinine measurements by proposed SPE-HPTLC procedure were used in the pilot studies for assessment of hazard from home ETS on the health status of elementary schoolboys, especially an increased risk for infectious respiratory track diseases.

Restrictions on smoking at home and urinary cotinine levels among children with asthma

OBJECTIVES

The purpose of this study was to determine the extent to which various levels of restrictions on smoking in the home may be associated with children's exposure to environmental tobacco smoke (ETS).

METHODS

The methodology consisted of a cross-sectional survey involving 249 children with asthma aged 1 to 11 attending hospital outpatient clinics, with at least one parent who smoked, linked to the child's urinary cotinine to creatinine ratios (CCR).

RESULTS

After adjustment for child's age, mother's smoking status, and total parental daily cigarette consumption, a total ban was associated with significantly lower urinary CCR levels (7.6 nmol/mmol) than bans with exceptions or limited smoking in the home. Where exceptions to bans were made (14.9 nmol/mmol), children's urinary CCR levels were no different from homes in which smoking was allowed in rooms the child rarely frequented (14.1 nmol/mmol). These two intermediate levels of restriction were in turn associated with significantly lower CCR levels than unrestricted smoking in the home (26.0 nmol/mmol).

CONCLUSIONS

Making exceptions to bans on smoking at home measurably undermines the protective effect of a ban. However, making some exceptions to a ban and limiting smoking to rooms where the child rarely goes may result in reduced exposure to ETS, compared with unrestricted smoking.

Involuntary smoking and asthma

Involuntary smoking is the third leading preventable cause of death, and among children it causes lower respiratory infections, middle ear disease, sudden infant death syndrome, and asthma. Half the world's children may be exposed to environmental tobacco smoke (ETS), exacerbating symptoms in 20% of children with asthma. Recent studies have reinforced previous conclusions that ETS exposure causes onset of childhood asthma and exacerbation of symptoms throughout life. The exact mechanisms by which this is accomplished are still unclear, as are the relative contributions of prenatal versus postnatal exposure. However, favorable health outcomes can be attained with reduced exposure. Among the few studies of ETS exposure reduction interventions, low-intensity advice methods appeared ineffective, and counseling parent smokers appeared successful. Direct counseling of school-aged children to avoid ETS has yet to be tested. Community norms may need to shift further in favor of protecting children and others from ETS before minimal interventions can be successful. This will require combined and ongoing efforts of the medical and public health establishments, in concert with legislation mandating tobacco-free public places and with ETS-related media campaigns.