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 and hair measurement of exposure to tobacco smoke

To assess the relation between nicotine and cotinine levels in hair and reported exposure to environmental tobacco smoke (ETS), hair samples from 112 children (aged 3 months to 10 years) and 76 of their mothers were analyzed and information on the smoking habits of household adults in the preceding 6 months recorded. It was found that the levels of nicotine in children's hair were related to the number of smokers in the house, and increased with the total number of cigarettes smoked by all household adults (P<0.0001). In a multiple regression analysis, mother's smoking was much more a contributor to children's nicotine levels than smoking by the father or other household adults. Cotinine levels were less strongly associated with reported ETS exposure than nicotine. There was a strong correlation between nicotine hair levels in children and mothers (r(s)=0.7, P<0.0001). However, nicotine levels in the hair of active smokers were not correlated with the reported number of cigarettes they smoked per day. In this population, there was a consistent relation between exposure to ETS (assessed by questionnaire) and dose (as measured by nicotine in hair). We conclude that hair nicotine levels rather than hair cotinine levels provide an informative and objective measure of ETS exposure. The number of cigarettes smoked by active smokers may not be an accurate measure of the total nicotine levels in their bodies.     

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.     

Questionnaire assessment of lifetime and recent exposure to environmental tobacco smoke

In a sample of 149 adult nonsmokers recruited in New Mexico in 1986, the authors assessed the reliability of questionnaire responses on lifetime exposure to tobacco smoke in the home. They also compared urinary cotinine levels with questionnaire reports of environmental tobacco smoke exposure during the previous 24 hours. The agreement of responses obtained on two occasions within six months was high for parental smoking during childhood: 94% for the mother and 93% for the father. For the amounts smoked by the mother and the father during the subject's childhood, the agreement between the two interviews was moderate: 52% and 39%, respectively. For the number of hours per day that each parent smoked in the home during the subject's childhood, the Spearman correlation coefficients also indicated only moderate reliability (r = 0.18 for maternal smoking and r = 0.54 for paternal smoking). For each set of interviews, responses concerning recent tobacco smoke exposure and urinary cotinine levels were correlated to only a modest degree. The authors conclude that adults can reliably report whether household members smoked during their childhood, but information on quantitative aspects of smoking is reported less reliably.     

Tobacco use behaviors and household smoking bans among Chinese Americans

PURPOSE: To assess the relationship between household smoking restrictions and smoking patterns among Chinese American adults. DESIGN: This is a cross-sectional analysis based on a National Institutes of Health-funded population-based household and telephone survey of 2537 Chinese American adults. SETTING: Two communities in New York City. SUBJECTS: The analyses focused on male current smokers (N = 600). MEASURES: Demographic characteristics, smoking status, household smoking restrictions, cigarettes smoked per day, and past quit attempts were based on self-reported data. RESULTS: Among current smokers, 37% reported living in a home with a complete smoking ban. Smokers with a full household smoking ban smoked fewer cigarettes on weekdays and weekends than smokers with no household smoking ban (p < or = .05) and were 3.4 times (p < .01) more likely to report having at least one quit attempt in the past 12 months. Smokers with knowledge of the dangers of environmental tobacco smoke (ETS) exposure were 2.8 times (p < or = .01) more likely to have at least one quit attempt in the last 12 months compared with those who were unaware of the danger of ETS and more likely to live in a smoke-free household. CONCLUSIONS: Smoke-free home policies and interventions to raise awareness among smokers of the dangers of ETS have the potential to significantly reduce tobacco use and exposure to household ETS among this immigrant population.     

Household smoking behaviours and exposure to environmental tobacco smoke among infants: are current strategies effectively protecting our young?

Objective: To determine the prevalence of infant exposure to environmental tobacco smoke (ETS) among infants attending child health clinics in regional NSW; the association between such exposure and household smoking behaviours; and the factors associated with smoking restrictions in households with infants. Methods: Parents completed a computer‐based questionnaire and infant urine samples were collected. Information was obtained regarding the smoking behaviours of household members and samples were analysed for cotinine. Results: Twenty seven per cent of infants had detectable levels of cotinine. Infant ETS exposure was significantly associated with the smoking status of household members, absence of complete smoking bans in smoking households and having more than one smoker in the home. Smoking households were significantly less likely to have a complete smoking ban in place. Conclusions: This study suggests that a significant proportion of the population group most vulnerable to ETS were exposed. Implications: Future efforts to reduce children's exposure to ETS need to target cessation by smoking parents, and smoking bans in households of infants where parents are smokers if desired reductions in childhood ETS‐related illness are to be realised.     

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.     

Environmental tobacco smoke and canine urinary cotinine level

Epidemiologic studies of companion animals such as dogs have been established as models for the relationship between exposure to environmental tobacco smoke (ETS) and cancer risk in humans. While results from these studies are provocative, pet owner report of a dog's ETS exposure has not yet been validated. We have evaluated the relationship between dog owner's report of household smoking by questionnaire and dog's urinary cotinine level. Between January and October 2005, dog owners presenting their pet for non-emergency veterinary care at the Foster Hospital for Small Animals at Cummings School of Veterinary Medicine, Tufts University, were asked to complete a 10-page questionnaire measuring exposure to household ETS in the previous 24 h and other factors. A free-catch urine sample was also collected from dogs. Urinary cotinine level was assayed for 63 dogs, including 30 whose owners reported household smoking and 33 unexposed dogs matched on age and month of enrollment. Urinary cotinine level was significantly higher in dogs exposed to household smoking in the 24 h before urine collection compared to unexposed dogs (14.6 ng/ml vs. 7.4 ng/ml; P=0.02). After adjustment for other factors, cotinine level increased linearly with number of cigarettes smoked by all household members (P=0.004). Other canine characteristics including age, body composition and nose length were also associated with cotinine level. Findings from our study suggest that household smoking levels as assessed by questionnaire are significantly associated with canine cotinine levels.     

Measures of maternal tobacco exposure and infant birth weight at term

This study was undertaken to determine the relation between self-reported number of cigarettes smoked per day and urine cotinine concentration during pregnancy and to examine the relations between these two measures of tobacco exposure and birth weight. Data were obtained from the Smoking Cessation in Pregnancy project, conducted between 1987 and 1991. Cigarette smoking information and urine cotinine concentration were collected for 3,395 self-reported smokers who were receiving prenatal care at public clinics in three US states (Colorado, Maryland, and Missouri) and who delivered term infants. General linear models were used to quantify urine cotinine variability explained by the number of cigarettes smoked per day and to generate mean adjusted birth weights for women with different levels of tobacco exposure. Self-reported number of cigarettes smoked per day explained only 13.9% of the variability in urine cotinine concentration. Birth weight declined as tobacco exposure increased; however, the relation was not linear. The sharpest declines in birth weight occurred at low levels of exposure. Furthermore, urine cotinine concentration did not explain more variability in birth weight than did number of cigarettes smoked. These findings should be considered by researchers studying the effects of smoking reduction on birth outcomes.     

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.     

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.     

How home-smoking habits affect children: a cross-sectional study using urinary cotinine measurement in Italy

Objectives

To assess the impact of different home-smoking rules and smoking habits of cohabitant on environmental tobacco smoke (ETS) exposure of children.

Methods

Information about 396 Italian children (5–11?years old) and cohabitants’ smoking habits was collected by a questionnaire. Exposure assessment was performed by determination of urinary cotinine (u-cotinine).

Results

Median u-cotinine concentrations in children significantly increased in a similar fashion as theoretical ETS exposure increase: cohabitants do not smoke (1.79?μg/g creatinine), cohabitant(s) smoker(s) never smoke at home (2.84), smoke at home only when children are out (3.90), and smoke at home even if children are in (6.02). Median u-cotinine levels of exposed children were associated to the strength of cohabitant’s smoking behaviours when smoker(s) consume daily a high number of cigarettes (≥?20) respect to light consumption (1–9) (4.52 and 3.24?μg/g creatinine).

Conclusions

The magnitude of ETS exposure in children is correlated with smoking habits and home-smoking precautions adopted by their cohabitants. Educational interventions on parents are essential to increase their awareness about ETS exposure and to teach correct behaviours to protect health of kids, especially in household environment.     

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.     

Exposure to Environmental Tobacco Smoke among Infants in Southern Thailand: A Study of Urinary Cotinine

We performed a survey to assess the exposure to environmental tobacco smoke (ETS) in 1-year-old infants in Thailand. Of the 725 infants, it was reported that 73.3% had household smoking and 40.7% had detectable urinary cotinine. Twenty-five infants (3.4%) had urinary cotinine in the range of adult heavy smokers. The prevalence of ETS exposure was significantly higher in infants with a father whose education was ≤ grade 6 than in those with father’s education >6 years (44.0% vs. 36.0%, p = 0.039). Data on the exposure to ETS among infants will provide prevalence information and identify population subgroups at increased risk for exposure.     

Heterogeneity in Smokers' Responses to Tobacco Control Policies

This paper uses unconditional quantile regression to estimate whether smokers' responses to tobacco control policies change across the distribution of smoking levels. I measure smoking behavior with the number of cigarettes smoked per day and also with serum cotinine levels, a continuous biomarker of nicotine exposure, using individual‐level repeated cross‐section data from the National Health and Nutrition Examination Surveys. I find that the cigarette taxes lead to reductions in both the number of cigarettes smoked per day and in smokers' cotinine levels. These reductions are most pronounced in the middle quantiles of both distributions in terms of marginal effects, but most pronounced in the lower quantiles in terms of tax elasticities. I do not find that higher cigarette taxes lead to statistically significant changes in the amount of nicotine smokers ingest from each cigarette. Copyright © 2015 John Wiley & Sons, Ltd.     

Spontaneous cigarette brand switching: consequences for nicotine and carbon monoxide exposure.

A group of smokers who had participated in smoking-related studies three to six years earlier were re-studied to assess changes in their smoking practices. Individuals who smoked the same brands of cigarettes showed no change in plasma cotinine (reflecting exposure to nicotine) or expired carbon monoxide (CO) concentration. Those who switched to cigarettes of lower nicotine yield (average decrease 38 per cent) showed reduced plasma cotinine concentrations, due primarily to smoking fewer cigarettes per day. The intake of nicotine per cigarette was not different. Subjects who smoked cigarettes of higher yield (102 per cent increase) had higher cotinine and CO levels, due to greater intake per cigarette.     

Active and passive exposure status to tobacco smoke of department store employees measured by cotinine ELISA

Quantitation of urinary cotinine, a major metabolite of nicotine, by an enzyme-linked immunosorbent assay (ELISA), was performed in parallel with questionnaires containing items on smoking status, such as active and/or passive smokers, the number of cigarettes smoked, and the presence or absence of active smokers in the surroundings in a department store (517 employees). The cotinine values corrected by creatinine (cotinine-creatinine ratios, CCRs) approximately conformed to the extent of self-recognition of their exposure status to tobacco-smoke, and were low in the order of active smokers, passive smokers and non-smokers who felt they were not exposed to tobacco-smoke. Occupational differences of the CCRs were not found in the employees. In the active smokers, the CCRs were increasing according to the number of cigarettes per day they smoked, and the values were nearly proportional to nicotine contents of cigarette in the moderate smokers who smoked 11-20 cigarettes per day. The CCRs of males were higher than those of females in the active smokers, which also agreed well with the numbers of cigarettes they smoked per day. In the passive smokers, the CCRs were remarkably and significantly higher in subjects who felt they were exposed to tobacco-smoke both in their workplaces and homes. Urinary CCRs measured by ELISA are thus found to be a reliable and excellent objective indicator of both active and passive exposure-status to tobacco-smoke.     

The exposure of nonsmoking and smoking mothers to environmental tobacco smoke during different gestational phases and fetal growth

We studied the impact of maternal exposure to environmental tobacco smoke (ETS) on birth weight (BW), low birth weight (LBW), and intrauterine growth retardation (IUGR) according to self-reported maternal smoking habits in a sample of 6,866 singleton births. We obtained data about parental characteristics and maternal active smoking (AS) and passive smoking at delivery via maternal questionnaires and medical records. We used three categories of smoking habits (nonsmokers and those who smoked 1-10 or >10 cigarettes per day) and defined ETS exposure as greater than or equal to 5 cigarettes per day smoked by others in the mother's presence. We used multiple regression and logistic regression procedures with adjustment for many associated covariates. We observed a significant reduction of the mean BW in infants of AS mothers. This reduction was only marginal for mothers who stopped smoking after recognizing their pregnancy. ETS exposure in 1,797 of 5,507 nonsmoking mothers reduced the mean BW of their infants by 53 g [95% confidence interval (CI), 24-82 g]. ETS exposure also significantly reduced BW in babies of AS mothers by 92 g (CI, 21-113 g) compared with BW of ETS-nonexposed AS mothers. The adjusted odds ratio (AOR) of LBW for ETS-exposed AS mothers was two times the LBW risk of ETS-nonexposed AS mothers(2.02; CI, 1.11-3.67); the AOR of ETS-exposed nonsmoking mothers was 1.51 (CI, 1.02-2.26). The AOR of IUGR for this group did not differ from unity (1.08; CI, 0.82-1.43). However, ETS exposure increased the AOR of IUGR for AS mothers from 1.64 (CI, 1.06-2.53) to 2.13 (CI, 1.70-2.67). ETS exposure reduced the BW of infants of nonsmoking mothers and contributed to additional BW reduction in infants of AS mothers. ETS exposure increased the risk of LBW but not that of IUGR in babies of nonsmoking mothers.     

Self-reported smoking, cotinine levels, and patterns of smoking in pregnancy

Non-pregnant adult smokers generally exhibit fairly stable smoking behaviour over time. In studies of this population, cotinine assays are considered a 'gold standard' measure of exposure to cigarette smoke; current smoking status can be validated with high sensitivity and specificity. In contrast, there is substantial within-person fluctuation in pregnancy smoking, as women try repeatedly to quit or cut down. As a result, cotinine measures may be of limited use for validation of amount smoked, as they are informative only about recent exposure, vary with individual smoking topography and are dependent on time lapsed since the last cigarette smoked. Thus, in reproductive epidemiology, where timing, intensity and duration of exposure are critical, self-reported history of cigarette consumption may be a more relevant fetal exposure than current smoking status. If there were substantial within-person variation over the course of pregnancy, numerous measures of cotinine would be needed to characterise patterns of fetal exposure and would not be feasible in many studies. We examined self-reported smoking patterns and compared them to patterns of urinary cotinine levels in a prospective study of 998 pregnant women, recruited 1988-92. Fluctuations in smoking were considerable and, while cotinine measures and self-reported number of cigarettes were highly correlated at any given time point across women (r=0.70), the within-person correlation between the patterns of self-reported number of cigarettes and cotinine levels was weaker (r=0.33). For researchers interested in fetal outcomes in which intensity and timing of exposure are critical, we conclude that self-reported variations in smoking during pregnancy may be a valid way to characterise detailed patterns of fetal exposure in epidemiological studies.     

Measuring exposure to environmental tobacco smoke (ETS): a developing country's perspective

AIMS: To assess exposure to ETS among nonsmokers in the community and examine the relation between various subjective and objective measures of exposure to ETS in a developing country's setting. METHODS: An interviewer-administered population-based survey of adults 18-65 years residing in Aleppo, Syria. From a total number of 2038 participants, a sub-sample of 419 nonsmokers (27.2% men, 72.8% women, mean age 34 years) underwent subjective and objective assessment of exposure to ETS (saliva cotinine, breath CO, self-reported measures of exposure combined into ETS exposure scale). RESULTS: Overall, 97.6% of adults nonsmokers assessed in this study, 72.9% of whom were women, have detectable saliva cotinine levels (mean +/- SD 1.7 +/- 1.5 ng/ml). Correlation between self-reported exposure measures and saliva cotinine was moderate with the strongest observed for number of cigarette smokers in the house, average number of cigarettes smoked daily in the house, house policy regarding smoking, and total ETS score (r 0.3-0.4). These same variables were among the best predictors of saliva cotinine according to stepwise linear regression analysis, but their individual relevance differed between men and women reflecting underlying differences in gender-based behavior-mobility patterns. Generally, subjective measures could explain 22% of the variability in cotinine levels in men and 19% in women. CONCLUSIONS: Exposure to ETS is universal among adult nonsmokers in Syria. Saliva cotinine correlated moderately with self-reported measures, whereby selected subjective measures can be as informative as composite scores incorporating multiple measures. Even in this environment of omnipresence of smoking, household restrictions seem to offer protection against ETS exposure.