Environmental tobacco smoke exposure in children: household and community determinants

Tobacco Smoke Exposure According to Location of Home Smoking in Israel: Findings from the Project Zero Exposure Study

Young children are particularly vulnerable to harms from tobacco smoke exposure (TSE). This study aimed to compare TSE: (1) between children who live in smoking families and those who do not; and (2) among children who live in smoking households with varying smoking locations. The data came from two studies that were conducted concurrently in Israel (2016-2018). Study 1: a randomized controlled trial of smoking families (n = 159); Study 2: a cohort study of TSE among children in non-smoking families (n = 20). Hair samples were collected from one child in each household. Baseline hair nicotine data were analyzed for 141 children in Study 1 and 17 children in Study 2. Using a logistic regression analysis (exposed vs. not exposed as per laboratory determination) and a linear regression (log hair nicotine), we compared TSE between: (1) children in Study 1 vs. Study 2; (2) children in families with different smoking locations in Study 1: balcony; garden, yard, or other place outside of the home; or inside the home (designated smoking areas within the home (DSAs) or anywhere). A higher proportion of children living in smoking households were measurably exposed to tobacco smoke (68.8%) compared to children living in non-smoking households (35.3%, p = 0.006). Among children from smoking families, 75.0% of those whose parents smoked in the house were exposed, while 61.8% of children whose parents restricted smoking to the porch (n = 55) were exposed, and 71.4% of those whose parents smoked outside the home (including gardens and yards) (n = 42) were exposed. In univariable and multivariable models, smoking location was not significantly associated with exposure. The majority of children in smoking families were measurably exposed to TSE, even if smoking was restricted to designated areas in the home, balconies, orgarden/yard/other outdoor areas. Reducing population smoking rates, particularly among parents, restricting smoking to at least 10 meters from homes and children, and denormalizing smoking around others are recommended to reduce population-level child TSE and tobacco-attributable disease and death.

Prevalence and factors associated with exposure to secondhand smoke (SHS) among young people: a cross-sectional study from the Gambia

BACKGROUND

Annually, 600 000 deaths are attributed to exposure of non-smokers to secondhand smoke (SHS). These include 165 000 among children, about 60% of which occur in Africa and Southeast Asia. As of 2017, only seven countries in the African region had comprehensive smoke-free legislation covering all public places. Given the increasing prevalence of smoking in many low-income countries, preventing exposure to SHS is an urgent public health priority, particularly in Sub-Saharan Africa.

OBJECTIVES

The objective of this study is to obtain a reliable and nationally representative estimate of the prevalence of exposure to SHS and to identify the major risk factors among young people in The Gambia.

SETTINGS AND METHODS

We used a two-stage cluster random sampling to select students in secondary schools throughout The Gambia and a self-administered questionnaire to collect data on demographic characteristics and detailed indicators of exposure to SHS.

RESULTS

Of the 10 392 eligible students, 10 289 (99%; 55% girls and 44% boys, age 12-20 years) participated. The proportion of students reporting any exposure to SHS was 97.0% (enclosed public places 59.2%, outdoor public places 61.4%, school 21.3% and home 38.2%), with 96.4% reporting some exposure outside the home. Exposure to SHS in the home was more common in girls and among older students. Parental education, living with parents and being sent to purchase cigarettes were associated with exposure to SHS both within and outside the home. More than 50% of students supported public smoking ban in both enclosed and outdoor public places. About 35% of students were unaware of the harmful effects of exposure to SHS.

CONCLUSIONS

Exposure to SHS is highly prevalent among students in The Gambia and occurs mostly outside of the home. Interventions to reduce SHS exposure in students are urgently needed.

Factors associated with secondhand smoke exposure prevalence and secondhand smoke level of children living with parental smokers: a cross sectional study

Factors that might account for the probability of children being exposed to secondhand smoke compared to those who are unexposed and characteristics associated with the urinary cotinine level (UCL) of those who are exposed were investigated. All households in a German region with a child aged 3 years or younger (n = 3,570) were invited to participate in a study that tested the efficacy of an intervention for reducing secondhand smoke exposure. In 1,282 households, at least one parent reported daily smoking. Among these, 915 (71.3%) participated in the study. For data analyses, we used a two-part model. Characteristics of the households associated with SHSE of the youngest child were analyzed, as well as characteristics associated with UCL among those exposed. Exposure to secondhand smoke was defined using a UCL ≥ 10 ng/ml. Secondhand smoke exposure was detected in 57.1% of the samples. Nursery attendance was associated with secondhand smoke exposure, in addition to the number of smokers living in the household, extent of home smoking ban and parental education. Among children exposed, nursery attendance, season of urine collection and age of the child were associated with UCL. Consideration of seasonal smoking behavior and a child's age at the time of intervention may increase attention to the adverse health effects of secondhand smoke exposure.

Effect of Submaximal Warm-up Exercise on Exercise-induced Asthma in African School Children

BACKGROUND

Regular physical activity has long been regarded as an important component of a healthy lifestyle. Exercise-induced asthma (EIA) is one of the major problems interfering with the performance of exercise. A warm-up exercise programme has been cited as a non-pharmacologic means of reducing EIA, but its effect has not been fully elucidated.

OBJECTIVE

The aims of this study were to determine the prevalence of unrecognized EIA in Pretoria primary school children, determine the effect of a warm-up exercise programme on EIA and to establish the relationship between history of allergy, family history of asthma and EIA.

METHODS

A random sample of 640 school children was selected. The study was divided into three phases. In phase one, a descriptive cross-sectional study was done using the standardized European Community Respiratory Health Survey (ECRHS) questionnaire. In phase two, non-asthmatic participants that returned a completed questionnaire were included in the field study. Pre-test and post-test experimental designs were used, where peak expiratory flow rate (PEFR) was measured at baseline and within ten minutes after exercise. A total of 340 subjects completed the Free Running Asthma Screening Test (FRAST); EIA was defined as a decrease in baseline PEFR ≥ 10% after exercise and 75 children (22%) had EIA. In phase three, 29 of the 75 subjects participated in the warm-up programme which was performed in the laboratory and subjects acted as their own controls. Predefined protocols for the study were followed.

RESULTS

Seventy-five (22%) of the 340 participants had EIA. The mean age, height and weight were 10.51 years, 139.26 cm and 33.45 kg, respectively. Exercise-induced asthma symptoms were cough (25%), chest pain (16%), wheeze (12%) and chest tightness (12%). The history of allergy was 75%, family history of allergy 40% and positive history of allergy when near animals, feathers or in dusty areas 38%. Wheezing during or after exercise, wheezing when near animals, feathers or in dusty areas and chest pain was significant (p < 0.05). The mean PEFR after exercise without warm-up was 4.43 L/min. The mean PEFR after exercise (warm-up) was 4.98. The mean percentage change in PEFR between exercise without warm-up and exercise with warm-up was 14.83%. The paired t-test showed a significant difference between PEFR with warm-up and PEFR without warm-up (p < 0.05).

CONCLUSION

There was a high prevalence of EIA among study participants. Exercise-induced asthma symptoms were significant for wheezing and chest pain. Exercise after warm-up was significant in reducing EIA. This study reports the effect of warm-up exercise on EIA and highlights the need to screen school children for EIA.

Determinants of exposure to second-hand tobacco smoke (SHS) among current non-smoking in-school adolescents (aged 11-18 years) in South Africa: results from the 2008 GYTS study

The aim of this study was to estimate the prevalence and identify correlates of second-hand tobacco smoke (SHS) among 6,412 current non-smoking school-going adolescents (aged 11 to 18 years) in South Africa. A cross-sectional study was carried out in 2008 in South Africa within the framework of the Global Youth Tobacco Survey. Overall, 25.7% of students were exposed to SHS at home, 34.2% outside of the home and 18.3% were exposed to SHS at home and outside of the home. Parental and close friends smoking status, allowing someone to smoke around you and perception that passive smoking was harmful were significant determinants of adolescent’s exposure to both SHS at home and outside of the home. Identified factors can inform the implementation of public health interventions in order to reduce passive smoking among adolescents.

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.

Environmental tobacco smoke exposure and respiratory morbidity in children

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

Correlates of home smoking bans among Mexican-Americans

PURPOSE

This study examines the individual and environmental correlates of home smoking bans among a population-based sample of Mexican-Americans. Design. A telephone survey on tobacco use and home policies was conducted using stratified, random sampling of listed phone numbers.

SETTING

Surveys were completed by telephone in San Diego, California.

SUBJECTS

The sample consisted of San Diego adult residents of Mexican descent (N=1103).

MEASURES

The interview included questions on home rules regarding smoking in the household and a number of potential correlates, based on the Behavioral Ecological Model (BEM). This model emphasizes the influence of family, social, and cultural factors on health behaviors.

RESULTS

Overall, 90.6% of all respondents reported a ban on smoking in the home. Multivariate analyses indicated that home bans on smoking are more likely among individuals that do not smoke, live with children, are more acculturated to U.S. society, report greater aversion to ETS, and/or report more social pressure against indoor smoking. In contrast, smoking bans are less likely among Mexican Americans who live with smokers.

CONCLUSIONS

Individual and environmental factors play a protective role by increasing the likelihood of smoking bans in the home of Mexican-descent individuals. These factors should be considered for the design of interventions to sustain and promote the adoption of smoking bans in the home among this and other populations.

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

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

PRACTICAL IMPLICATIONS

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

Prevalência de sintomas de asma e tratamento de crianças e adolescentes de 2 a 14 anos no Campus Aproximado da PUCRS

INTRODUÇÃO: Nas últimas décadas tem havido aumento da prevalência da asma. OBJETIVO: Determinar a prevalência de sintomas de asma em crianças e adolescentes de 2 a 14 anos em Porto Alegre (RS), relacionando-a com o perfil socioeconômico, tratamento e hábito de fumar intradomiciliar. MÉTODO: Estudo transversal em que foram entrevistadas todas as famílias atendidas em junho de 2000. RESULTADOS: A prevalência de sintomas de asma foi de 49,5%. Em 66,8% das famílias a renda era inferior a quatro salários mínimos e em mais de 50% a escolaridade materna e paterna era menor que cinco anos. Em 98,5% não havia utilização de tratamento preventivo para asma. Nas 174 famílias estudadas 38,7% das mães, 43,7% dos pais e 32,7% de ambos eram fumantes. Houve associação entre as seguintes variáveis: exposição ao fumo intradomiciliar e número de crises de asma no último ano (p = 0,02; RR = 2,9; IC: 1,1 - 4,5); escolaridade materna e número de crises no último ano (p = 0,03; RR = 2,03; IC: 1,01 - 4,19); aglomeração e número de crises no último ano entre as crianças expostas ao fumo (p = 0,04; RR = 2,7; IC: 1,4 - 5,1); hospitalização e número de crises no último ano (p = 0,004; RR = 1,46; IC: 1,15 -1,86); hospitalização e aglomeração (p = 0,03; RR = 1,47; IC: 1,15 -1,86). Nos menores de cinco anos, houve associação entre fumo materno e número de crises no último ano (p = 0,03; RR = 1,79; IC: 1,04 - 3,08). CONCLUSÃO: A prevalência de sintomas de asma foi alta. A comunidade estudada é limitada do ponto de vista socioeconômico e não trata adequadamente a enfermidade, o que demonstra necessidade de atendimento priorizado, normatizado e com insumos e processos avaliativos para controle da doença.

Exposure to environmental tobacco smoke and cognitive abilities among U.S. children and adolescents

We used the Third National Health and Nutrition Examination Survey (NHANES III), conducted from 1988 to 1994, to investigate the relationship between environmental tobacco smoke (ETS) exposure and cognitive abilities among U.S. children and adolescents 6-16 years of age. Serum cotinine was used as a biomarker of ETS exposure. Children were included in the sample if their serum cotinine levels were less than or equal to 15 ng/mL, a level consistent with ETS exposure, and if they denied using any tobacco products in the previous 5 days. Cognitive and academic abilities were assessed using the reading and math subtests of the Wide Range Achievement Test-Revised and the block design and digit span subtests of the Wechsler Intelligence Scale for Children-III. Analyses were conducted using SUDAAN software. Of the 5,365 6- to 16-year-olds included in NHANES III, 4,399 (82%) were included in this analysis. The geometric mean serum cotinine level was 0.23 ng/mL (range, 0.035-15 ng/mL); 80% of subjects had levels < 1 ng/mL. After adjustment for sex, race, region, poverty, parent education and marital status, ferritin, and blood lead concentration, there was a significant inverse relationship between serum cotinine and scores on reading (beta = -2.69, p = 0.001), math (beta = -1.93, p = 0.01), and block design (beta = -0.55, p < 0.001) but not digit span (beta = -0.08, p = 0.52). The estimated ETS-associated decrement in cognitive test scores was greater at lower cotinine levels. A log-linear analysis was selected as the best fit to characterize the increased slope in cognitive deficits at lower levels of exposure. These data, which indicate an inverse association between ETS exposure and cognitive deficits among children even at extremely low levels of exposure, support policy to further restrict children's exposure.

The relationship between housing and health: children at risk

In November 2002, the National Center for Healthy Housing convened a 2-day workshop to review the state of knowledge in the field of healthy housing. The workshop, supported with funds from the U.S. Centers for Disease Control and Prevention's National Center for Injury Prevention and Control and National Center for Environmental Health, was unique in that it focused solely on the effect of housing on children's health and the translation of research findings into practical activities in home construction, rehabilitation, and maintenance. Participants included experts and practitioners representing the health, housing, and environmental arenas. Presentations by subject-matter experts covered four key areas: asthma, neurotoxicants, injury, and translational research. Panel discussions followed the presentations, which generated robust dialogue on potential future research opportunities and overall policy gaps. Lack of consensus on standard measurements, incomplete understanding about the interaction of home hazards, inadequate research on the effectiveness of interventions, and insufficient political support limit current efforts to achieve healthy housing. However, change is forthcoming and achievable. Key words: asthma, childhood exposure, environmental toxicants, healthy housing, lead poisoning.

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.

Determinants of children's exposure to environmental tobacco smoke (ETS): a study in Southern Germany

Maternal smoking has been repeatedly found to be the most important determinant of children's exposure to environmental tobacco smoke (ETS). Here, we further investigated predictors for the urinary cotinine/creatinine ratio (CCR, ng/mg) in 1220 preschool children for the year 1996. Children from smoking homes (35.1%) had significantly higher CCR than children from nonsmoking homes (mean: 55.5 vs. 14.9 ng/mg). The level of education of the parents was a strong predictor for CCRs even after adjusting for number of cigarettes smoked, maternal smoking and dwelling space. Additionally, dwelling space was inversely related to children's urinary cotinine level. The CCR- levels in children investigated in 1996 and 1998 were significantly correlated (Pearson's r=0.67). The parents of 806 children agreed for a visit to their homes. In 79 of the 536 (14.7%) of the self-reported, nonsmoking households, smoking was admitted during the visit. The mean urinary CCR of these children was 25.2 ng/mg. We conclude that in addition to parental smoking behaviour, other variables such as dwelling space and social and educational status predict the children's exposure to ETS. Our data also revealed that a considerable percentage of parents denied the ETS exposure of their children at home.

Intérêt des différents marqueurs biologiques dans l'évaluation du tabagisme

Tobacco exposure can be assessed by the measurement of several markers in biological fluids. These markers are more or less specific for tobacco and the different methods to measure them out differ in terms of sensibility, specificity, ease of use and cost. The clinician prescribing a dosage for a patient has to take all these parameters into account to make an accurate choice. In this article, we have analysed the usefulness of the main biological tobacco markers in the follow-up of smokers and compared their methods of dosage. We propose several indications and point out the interest of relevant markers to realize objective measurements of smoking habits.

Evidence for gene-environment interactions in a linkage study of asthma and smoking exposure

BACKGROUND

Asthma, a common and chronic disease of the airways, has a multifactorial cause involving both genetic and environmental factors. As a result, mapping genes that influence asthma susceptibility has been challenging.

OBJECTIVE

This study tests the hypothesis that inclusion of exposure to environmental tobacco smoke (ETS), a potential risk factor for asthma, would improve the ability to map genes for asthma.

METHODS

By using 144 white families from the Collaborative Study for the Genetics of Asthma, environmental information about exposure to ETS during infancy was incorporated into a genome-wide multipoint linkage analysis. Statistical significance of observed gene-environment interactions was assessed by means of simulation.

RESULTS

Three regions with nominal evidence for linkage when stratified on the basis of ETS exposure were identified (P <.01) and showed a significant increase from the baseline lod score (1p at 97 cM, D1S1669-D1S1665; 5q at 135 cM, D5S1505-D5S816; and 9q at 106 cM, D9S910; all P <.05). In addition, 2 other regions, although not meeting nominal significance after stratification on the basis of ETS exposure, showed a significant increase from baseline lod score when ETS was taken into account (1q at 240 cM, D1S549; 17p at 3 cM, D17S1308; all P <.01).

CONCLUSION

These results illustrate how evidence for linkage of asthma can depend on exposure to an environmental factor, such as ETS. Future linkage analyses should include information on suspected environmental factors for asthma to help target new candidate susceptibility genes for asthma.

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.

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.

Pre- and postnatal parental smoking and wheeze in infancy: cross cultural differences. Avon Study of Parents and Children (ALSPAC) Study Team, European Longitudinal Study of Pregnancy and Childhood (ELSPAC) Co-ordinating Centre

In longitudinal cohort studies, the relationships between prenatal and postnatal tobacco smoke exposure and infant wheezing illnesses were compared in two geographically defined populations in Avon, UK and Brno and Znojmo in the South Moravian Region of the Czech Republic. Pregnant females living in defined regions and with expected dates of delivery between defined dates were recruited. Females completed self-report questionnaires during pregnancy and when their infant was 6 months old. For this analysis, responses to questions about smoking during pregnancy, environmental tobacco smoke (ETS) exposure and reported wheezing illnesses of infants at 6 months after birth were used. Odds ratios for wheeze in relation to the smoking variables were calculated with adjustment for potential confounding effects. The prevalence of smoking during pregnancy was higher in Avon (17.5%) than the Czech Republic (7.1%). Exposure of infants to ETS during the first 6 months after birth was also reported to be higher in Avon (35.5%) than the Czech Republic (9.7%). The prevalence of reported wheezing by 6 months of age was 21.4% in Avon and 10.3% in Brno and Znojmo. In Avon, there was a significant relationship between infant wheeze and maternal smoking during pregnancy (odds ratio (95% confidence interval) 1.30 (1.09-1.56), p=0.004) but not with environmental exposure after birth (1.11 (0.98-1.25)). In contrast, in Brno and Znojmo in the Czech Republic, there was a significant relationship between infant wheeze and ETS exposure (1.66 (1.17-2.36), p=0.04) but not with maternal smoking during pregnancy (0.99 (0.64-1.55)). This study demonstrated an apparent difference in the associations between prenatal and postnatal tobacco smoke exposure and infant wheezing illnesses in two populations with different smoking prevalence. The relationships were independent of a number of potential confounding variables that have been associated with infant wheezing. Possible explanations of these observations include dose-related effects of prenatal and postnatal tobacco smoke exposure of infants.