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.     

A passive smoking screening program for children

BACKGROUND: There has been no report to date on mass screening of passive smoking in children using biomarkers. METHOD: To identify children exposed to actual environmental tobacco smoke (ETS), 261 children were divided into the following 3 groups: (A) both parents smoke; (B) one parent smokes; and (C) no parent smokes. Child urinary cotinine measurement and a parent questionnaire were obtained. RESULTS: Urinary cotinine was positive (>10 ng/ml) in 92 (35.2%) of the 261 children. Of the 92 children, 29 were classified into group A, 47 into group B, and 16 into group C. The percentages of children who tested positive for urinary cotinine in groups A, B, and C were 56.9%, 31.1%, and 27.1%, respectively. However, in group B, the percentage of children who tested positive for urinary cotinine was significantly higher if only the mother smoked (47.1%) than if only the father smoked (29.1%) (P<0.05). The mean+SD urinary cotinine level in group A was 12.9+/-6.5 ng/ml, and that in group B was 10.4+/-3.8 ng/ml if the mother smoked and 5.4+/-2.6 ng/ml if the father smoked. CONCLUSIONS: This smoking screening program may be useful in identifying children with actual ETS exposure and motivating their parents to either quit smoking or modify their smoking behavior around children.     

Determinants of passive smoking in children in Edinburgh, Scotland.

OBJECTIVES. Using saliva cotinine as a quantitative marker, we examined the contribution of factors other than parental smoking to children's passive exposure to tobacco smoke. METHODS. Saliva specimens from a random sample of 734 7-year-old schoolchildren in Edinburgh, Scotland, were analyzed for cotinine. Their parents completed a questionnaire covering smoking habits and conditions in the home. RESULTS. A number of independent predictors of cotinine were identified in addition to the main one of smoking by household members. These predictors included home ownership, social class, day of the week, season of the year, number of parents present, crowding in the home, the number of children in the household, and sex. Cotinine was higher in children from less advantaged backgrounds, during winter, on Mondays, in girls, and when fewer other children were present. The effects were similar between children from nonsmoking and smoking homes. CONCLUSIONS. Questionnaire measures of parental smoking are insufficient to fully characterize young children's exposure to passive smoking. Because socioeconomic variables contribute to measured exposure, passive-smoking studies that treat class as a confounder and control for it may be overcontrolling.     

Validation of a five-question survey to assess a child's exposure to environmental tobacco smoke

PURPOSE: To study the potentially adverse health effects of environmental tobacco smoke (ETS) exposure in young children, a short five-question survey was developed to identify routine exposure to ETS in a large epidemiological study. METHODS: The survey is administered to parents of a healthy cohort of children starting at age 3 months. To validate the survey, urinary cotinine levels were measured on 50 children from this cohort who were selected based on ETS exposure as reported in the survey: 24 with no exposure and 26 with exposure. Cotinine was adjusted for creatinine. RESULTS: Overall, children with some form of reported ETS exposure had urinary cotinine levels 7.5 times higher than those who were not exposed. Analysis of variance shows that mean levels of log transformed cotinine in children whose parent(s) smoke in the home, parent(s) who smoke but not in the home, and non-smoking parents are 137.13, 75.60, and 43.28 respectively (p = 0.0009), indicating decreasing levels of cotinine as reported exposure decreases. Using a cut-point of 30 ng/mg of cotinine to differentiate unexposed and exposed to ETS, we found 80% agreement with our survey. A Spearman's ranked correlation coefficient of 0.62 indicates a direct relationship between cotinine and an ETS exposure intensity score (p < 0.0001).CONCLUSIONS: These results suggest that the 5-question survey reflects the child's exposure to passive smoke and that the survey is sensitive to varying levels of 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.     

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.     

Racial differences in exposure to environmental tobacco smoke among children

Exposure to environmental tobacco smoke (ETS) is a major cause of morbidity and mortality among U.S. children. Despite African-American children's having a lower reported exposure to tobacco compared to whites, they suffer disproportionately from tobacco-related illnesses and have higher levels of serum cotinine than white children. The goal of this study was to test whether African-American children have higher levels of serum and hair cotinine, after accounting for ETS exposure and various housing characteristics. We investigated the level of cotinine in both hair and serum in a sample of 222 children with asthma. Using a previously validated survey for adult smokers, we assessed each child's exposure to ETS. We collected detailed information on the primary residence, including home volume, ventilation, and overall home configuration. Despite a lower reported ETS exposure, African-American children had higher mean levels of serum cotinine (1.41 ng/mL vs. 0.97 ng/mL; p = 0.03) and hair cotinine (0.25 ng/mg vs. 0.07 ng/mg; p < 0.001) compared with white children. After adjusting for ETS exposure, housing size, and other demographic characteristics, serum and hair cotinine levels remained significantly higher in African-American children (ss = 0.34, p = 0.03) than in white children (ss = 1.06, p < 0.001). Housing volume was significantly associated with both serum and hair cotinine but did not fully explain the race difference. Our results demonstrate that, despite a lower reported exposure to ETS, African-American children with asthma had significantly higher levels of both serum and hair cotinine than did white children. Identifying causes and consequences of increased cotinine may help explain the striking differences in tobacco-related illnesses.     

“Marriage to a smoker” may not be a valid marker of exposure in studies relating environmental tobacco smoke to risk of lung cancer in Japanese non-smoking women

There is no direct evidence that workplace environmental tobacco smoke (ETS) increases lung cancer risk. Demands for regulation of workplace smoking are based on studies reporting increased risk in non-smoking women whose husbands smoke. Although denying smoking can artificially elevate risk estimates, and although many studies reporting an increase have been conducted in Asia, no previous study of smoking habit misclassification has been conducted there. In this study 400 married Japanese women answered questions on smoking and ETS exposure and supplied urine for cotinine analysis. Of 106 with a cotinine/creatinine ratio (CCR) indicating current smoking ( > 100 ng/mg), 22 reported never smoking. These misclassified smokers had a median CCR (1408 ng/mg) similar to the 78 self-reported current smokers (1483 ng/mg). Of current smokers, 89.7% had a currently smoking husband, while this was true of 51.0% of non-smokers. Among 264 confirmed nonsmokers (with CCR < 100 ng/mg), CCR was non-significantly lower if the husband smoked (11.51 vs 17.98 ng/mg) and was unrelated to various indices of smoking by the husband. Japanese epidemiological studies using marriage to a smoker to index ETS exposure may therefore have compared groups with similar ETS exposure, suggesting that associations reported between lung cancer and this index in some of these studies may result from bias. While other biases, including confounding, may also be important, bias resulting from smoking misclassification combined with husband/wife smoking concordance is shown to be of major concern. The high misclassification rates in Japan, much higher than in Western populations, undermine conclusions from epidemiological studies conducted there.     

Children's exposure to environmental tobacco smoke: using diverse exposure metrics to document ethnic/racial differences

Four metrics were used to assess exposure to environmental tobacco smoke (ETS) for a probability sample (n = 152) of elementary school-age children in two economically disadvantaged neighborhoods: a) caregiver responses to a baseline questionnaire (BQ) about smoking status and behavior; b) 48-hr time-activity (T-A) data on location and time spent by children in the presence of tobacco smoke; c) total urinary cotinine as a marker for nicotine uptake; and d) urinary NNAL [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol] + NNAL-Gluc [4-(methylnitrosamino)-1- (3-pyridyl)-1-(O-beta-D-glucopyranuronosyl)butane] as a marker for uptake of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Consistent differences in ETS exposure by ethnicity and race were observed. Although data were insufficient to determine differences for NNAL + NNAL-Gluc, BQ responses, T-A data, and cotinine levels all indicated that average ETS exposure was highest for African-American children, moderately high for those designated "other" (white, Southeast Asian, Native American), moderately low for Hispanic children, and lowest for Somali immigrant children. For example, in February 2000, mean cotinine levels were 14.1 ng/mL for African Americans, 12.2 ng/mL for other, 4.8 ng/mL for Hispanics, and 4.4 ng/mL for Somalis. The BQ and T-A data together were reasonably good predictors of total cotinine levels (adjusted r2 = 0.69), and based on limited data, measured total cotinine values were a relatively good predictor of NNAL + NNAL-Gluc (adjusted r2 = 0.73). The results suggest that when children are exposed to ETS primarily in their homes, questionnaires and T-A logs might be effective screening tools for identifying those likely to experience higher uptake of nicotine.     

Personal exposure to environmental tobacco smoke: salivary cotinine, airborne nicotine, and nonsmoker misclassification.

A large study was conducted to assess exposure to environmental tobacco smoke (ETS) in a geographically dispersed study population using personal breathing zone air sampling and salivary cotinine levels. Approximately 100 self-reported nonsmoking subjects in each of 16 metropolitan areas were recruited for this investigation. Cumulative distributions of salivary cotinine levels for subjects in smoking and nonsmoking homes and workplaces exhibited a general trend of decreasing salivary cotinine levels with decreasing time spent in smoking environments. Median salivary cotinine levels for the four experimental cells in the study (product of smoking and nonsmoking home and workplaces) were comparable to those reported for a large national study of serum levels of cotinine (Third National Health and Nutrition Examination Survey, NHANES III), when the latter was corrected for expected differences between serum and saliva concentrations. However, the most highly exposed group in this study had a median salivary cotinine concentration approximately a factor of 2 greater than that of the comparable group in the NHANES III study. Misclassification rates, both simple (for self-reported nonsmokers) and complex (self-reported lifetime never smokers), were near the median of those reported for other studies. Estimated misclassification rates for self-reported lifetime never-smoking females are sufficiently high (2.95% using a discrimination level of 106 ng/ml) that, if used in the Environmental Protection Agency (EPA) risk assessment related to ETS and lung cancer, would place the lower 90% confidence interval (CI) for relative risk at nearly 1.00, i.e., no statistically significant increased risk. For the 263 most highly exposed subjects in the study whose self-reported nonsmoking status was accurate, the correlation between airborne exposure to nicotine and average salivary cotinine is so small, on an individual basis, that it makes the relationship useless for estimating exposure on a quantitative basis. When subjects are grouped according to likely categories of nicotine exposure, correlation between group median airborne nicotine exposure and salivary cotinine level increases dramatically. The comparison improves for the most highly exposed subjects, suggesting that such quantitative comparisons are useful for only those subjects who are exposed to the higher levels of ETS. However, airborne nicotine exposure for most of the subjects does not account for estimated systemic levels of nicotine, based on salivary cotinine levels.     

Effect of feedback regarding urinary cotinine and brief tailored advice on home smoking restrictions among low-income parents of children with asthma: a controlled trial.

BACKGROUND: Since most smoker parents of children with asthma are unable to quit, an alternative measure that would reduce their children's exposure to environmental tobacco smoke (ETS) is to ban smoking in the home. METHODS: Compared with 136 usual-care controls, 128 intervention-group parents recruited from South Australian pediatric hospital outpatient waiting rooms were given written and verbal feedback about their 1- to 11-year-old child's urinary cotinine-to-creatinine level, information booklets, and two telephone calls encouraging a ban on smoking at home. RESULTS: At 6 months, 49.2% of the intervention group reported having banned smoking in the home compared with 41.9% of controls, but the differential rate of change from baseline was not significant (P = 0.40). At follow-up, there were no significant differences between groups in the percentage reporting bans on smoking in the car, the mean reduction from baseline in total daily consumption or consumption in front of the child, children's urinary cotinine level, or parental smoking cessation. CONCLUSIONS: The intervention did not change parents' propensity to create or maintain bans on smoking in their homes or otherwise change smoking habits to reduce their children's exposure to ETS. More intensive interventions may be required to achieve change among low-income smoker parents of children with asthma.     

Smoking in the home: changing attitudes and current practices.

OBJECTIVES: Trends in attitudes and current practices concerning smoking in the home were examined. METHODS: Data from population-based surveys of adults in Ontario, Canada, were analyzed. RESULTS: Between 1992 and 1996, the percentage of respondents who agreed that parents spending time at home with small children should not smoke increased from 51% to 70%. In 1996, 34% of the homes surveyed were smoke-free. Smoke-free homes were associated with nonsmoking respondents and with the presence of children and no daily smokers in the home. Only 20% of homes with children and any daily smokers were smoke-free. CONCLUSIONS: Efforts are needed to assist parents in reducing children's exposure to environmental tobacco smoke in the home.     

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.     

Comparison of parental reports of smoking and residential air nicotine concentrations in children

Background

Using questionnaires to assess children''s residential exposure to environmental tobacco smoke (ETS) may result in misclassification from recall and response bias. Questionnaire data have frequently been validated against urinary cotinine measurements, but rarely against actual measurements of residential air nicotine.

Objective

To compare questionnaire reported smoking with air nicotine concentrations in a large population of children and with urinary cotinine levels in a subpopulation; and to assess the potential impact of the symptom status of the children on the agreement between different measures of exposure.

Methods

The authors assessed residential exposure to ETS in 347 German, 335 Dutch, and 354 Swedish preschool and schoolchildren by questionnaire and air nicotine measurements, and in a subset of 307 German children by urinary cotinine measurements. They then compared the different measures of ETS exposure.

Results

In all countries, air nicotine concentrations increased with increasing questionnaire reported smoking in a dose‐response fashion. Specificity and negative predictive values of questionnaire reports for nicotine concentrations were excellent. Sensitivity and positive predictive values were moderate to good. Excluding occasional smokers, the overall percentage of homes misclassified was 6.9%, 6.7%, and 5.1% in Germany, the Netherlands, and Sweden, respectively. Similar results were found for the agreement of urinary cotinine concentrations with questionnaire reports and air nicotine levels. There was no indication of underreporting by parents of symptomatic children.

Conclusion

Despite some misclassification, questionnaire reports are an inexpensive and valid estimate of residential ETS exposure among preschool and school children.     

Assessment of smoking behaviors in the home and their influence on children's passive smoking: development of a questionnaire

PURPOSE: To construct and validate a questionnaire aiming to measure children's exposure to environmental tobacco smoke (ETS) in the home. METHODS: The development of the instrument included epidemiological studies, qualitative interviews, pilot studies, and validation with biomarkers and is described in seven consecutive steps. Parents of preschool children, from different population-based samples in south-east Sweden, have participated in the studies. RESULTS: Content and face validity was tested by an expert panel and core elements for the purpose of the instrument identified. Reliability was shown with test-retest of the first version. The validation with biomarkers indicated that the sensitivity of the instrument was high enough to discriminate between children's ETS exposure levels. Cotinine/creatinine levels were related to parents' described smoking behaviors. Differences were shown between children from non-smoking homes, and all groups with smoking parents, independent of their smoking behavior (p < 0.01), as well as between parents smoking strictly outdoors and parents reporting indoor smoking (p < 0.001). CONCLUSION: The results indicate that the presented instrument can be used to discriminate between different levels of ETS exposure and when children's level of tobacco smoke exposure is to be assessed.     

Environmental tobacco smoke exposure in children in two districts of the Czech Republic

In the course of epidemiologic studies on the health of preschool children in the Teplice and Prachatice districts of the Czech Republic, we have recorded the frequency of smokers in the families of the children under study and the exposure of the children to environmental tobacco smoke (ETS) by assaying urinary cotinine levels. Questionnaires were administered at the age of 3 years (children born 1994-1996) or 4.5 years (children born 1997-1998). Out of 1128 respondents, 35.6% of the mothers and 48.9% of their husbands/partners were smokers. Taking into account other adult smokers, 41.6% of children lived in households without smokers and 30.1% in households with one smoker. There were more smokers among both mothers and fathers in Teplice than in the Prachatice district (mothers: 41.1% vs. 28.5%, P=0.017; fathers: 50.8% vs. 46.5%, NS). Cotinine concentration in the urine was determined using a radioimmunoassay in 523 pairs of mothers and children at the age of 4.5 years. A level higher than 500 ng cotinine per mg creatinine (our cut-off for active smoking) was detected in 199 out of 523 mothers (38%). Using 20 ng/mg as the cut-off, 48.2% of 523 children were exposed to ETS. There were more ETS-exposed children in Teplice than in the Prachatice district (59.2% vs. 34.7%, P<0.001). When cotinine levels were measured in 479 of these children at the age of 6-7 years, the percentage of children exposed to ETS decreased to 36.5%. However, the difference between Teplice and Prachatice children persisted (44.6% vs. 27.8%). Our results suggest that in the Czech Republic, children under 5 years of age are significantly exposed to tobacco smoke and that more effective regulatory measures are needed to decrease the prevalence of smoking.     

Passive smoking in Germany and Poland: comparison of exposure levels, sources of exposure, validity, and perception.

Nonsmoking females age 35-65 years from Bremen, Germany (91 women), and Opole, Poland (98 women), were interviewed about their recent passive smoking exposure. We obtained urine samples at the time of interview and determined the concentration of cotinine as an indicator of tobacco smoke exposure. In Poland and in Germany, the vast majority of nonsmoking women are involuntarily exposed to environmental tobacco smoke (ETS). Polish women had slightly higher exposure levels than German women, with overall means of 9.93 and 8.65 ng cotinine/mg creatinine, respectively. Smoking by the husband was the major source of exposure in both study groups. In the Polish group, the work place was also an important source of ETS exposure. The validity of self-reported passive smoking exposure was found to be generally good; it was somewhat better in the German study group. A negative attitude toward tobacco smoke was slightly stronger among the German women. The percentage of women misreporting their active smoking status was low.     

Cord serum cotinine as a biomarker of fetal exposure to cigarette smoke at the end of pregnancy

This study investigated the association between biomarkers of fetal exposure to cigarette smoke at the end of pregnancy, cotinine in cord serum and in maternal and newborn urine samples, and quantitative measurement of smoking intake and exposure evaluated by maternal self-reported questionnaire. Study subjects were 429 mothers and their newborns from a hospital in Barcelona, Spain. A questionnaire including smoking habits was completed in the third trimester of pregnancy and on the day of delivery. Cotinine concentration in cord serum was associated with daily exposure to nicotine in nonsmokers and with daily nicotine intake in smokers. The geometric mean of cotinine concentration in cord serum statistically discriminated between newborns from nonexposed and exposed nonsmoking mothers, and between these two classes and smokers, and furthermore was able to differentiate levels of exposure to tobacco smoke and levels of intake stratified in tertiles. Urinary cotinine levels in newborns from nonsmoking mothers exposed to more than 4 mg nicotine daily were statistically different from levels in two other categories of exposure. Cotinine concentration in urine from newborns and from mothers did not differentiate between exposure and nonexposure to environmental tobacco smoke (ETS) in nonsmoking mothers. Cord serum cotinine appeared to be the most adequate biomarker of fetal exposure to smoking at the end of pregnancy, distinguishing not only active smoking from passive smoking, but also exposure to ETS from nonexposure.