Use of urinary cotinine and questionnaires in the evaluation of infant exposure to tobacco smoke in epidemiologic studies

Clinical characteristics and factors associated with severe acute respiratory infection and influenza among children in Jingzhou, China

BACKGROUND

Influenza is an important cause of respiratory illness in children, but data are limited on hospitalized children with laboratory-confirmed influenza in China.

METHODS

We conducted active surveillance for severe acute respiratory infection (SARI; fever and at least one sign or symptom of acute respiratory illness) among hospitalized pediatric patients in Jingzhou, Hubei Province, from April 2010 to April 2012. Data were collected from enrolled SARI patients on demographics, underlying health conditions, clinical course of illness, and outcomes. Nasal swabs were collected and tested for influenza viruses by reverse transcription polymerase chain reaction. We described the clinical and epidemiological characteristics of children with influenza and analyzed the association between potential risk factors and SARI patients with influenza.

RESULTS

During the study period, 15 354 children aged <15 years with signs and symptoms of SARI were enrolled at hospital admission. severe acute respiratory infection patients aged 5-15 years with confirmed influenza (H3N2) infection were more likely than children without influenza to have radiographic diagnosis of pneumonia (11/31, 36% vs 15/105, 14%. P<.05). Only 16% (1116/7145) of enrolled patients had received seasonal trivalent influenza vaccination within 12 months of hospital admission. Non-vaccinated influenza cases were more likely than vaccinated influenza cases to have pneumonia (31/133, 23% vs 37/256, 15%, P<.05). severe acute respiratory infection cases aged 5-15 years diagnosed with influenza were also more likely to have a household member who smoked cigarettes compared with SARI cases without a smoking household member (54/208, 26% vs 158/960, 16%, P<.05).

CONCLUSIONS

Influenza A (H3N2) virus infection was an important contributor to pneumonia requiring hospitalization. Our results highlight the importance of surveillance in identifying factors for influenza hospitalization, monitoring adherence to influenza prevention and treatment strategies, and evaluating the disease burden among hospitalized pediatric SARI patients. Influenza vaccination promotion should target children.

Adverse circulatory effects of passive smoking during infancy: surprisingly strong, manifest early, easily avoided

AIM

To compare blood pressure reactions (BPR) of infants to mild stress for evidence of adverse cardiovascular effects of passive exposure to tobacco smoke during pregnancy and early infancy.

METHODS

An observational field study conducted in Crete. We compared 4- to 6-month olds of lifelong nonsmokers minimally (controls, n = 9) or frequently exposed to tobacco smoke (passive smokers; n = 10) with those born to habitual smokers (n = 6). Smoke exposure was verified biochemically (urine cotinine each trimester and at study). We recorded beat-to-beat blood pressure (BP) during brief repositioning manoeuvres performed during a daytime nap and analysed BPR (% change in BP during head-up tilt) for associations with maternal and infant cotinine.

RESULTS

We observed a 20-fold difference between BPR of infants of controls versus passive smokers - exceptional given number of infants (α error/confidence level <10% i.e. power >90%). The BPR declined linearly as the infant's (but not mother's) cotinine level rose (p = 0.04), indicating abnormal BPR was caused mainly by postnatal smoke exposure. Infants of active smokers differed from those of passive smokers.

CONCLUSION

Cardiovascular effects of passive smoking by a newborn infant manifest early on and are exceptionally strong. They can be largely avoided by keeping the home smoke rigorously free.

Maternal smoking during pregnancy, polymorphic CYP1A1 and GSTM1, and lung-function measures in urban family children

PURPOSE

Understanding the interplay between genes and in-utero tobacco exposure in affecting child lung development is of great significance. In this study, we tested the hypothesis that tobacco-related lung-function reduction in children differs by maternal polymorphic genes Cytochrome P450 1A1 (CYP1A1) and Glutathione S-transferase Mu 1 (GSTM1).

MATERIALS AND METHODS

Data were collected among 370 children (6-10 years old, 81.6% African-Americans) and their biological mothers visiting a large children's hospital. Study hypotheses were tested using multiple regression method.

RESULTS

Among the study sample, 143 mothers smoked throughout pregnancy and 72 smoked on a daily basis. Spirometric measures (mean±SD) included were: forced vital capacity (FVC)=1635±431 mL, forced expiratory volume in the first 1s (FEV1)=1440 ±360 mL, percent FEV1/FVC ratio=89±12, and forced expiratory flow between the 25% and 75% of FVC (FEF25-75)=1745±603 mL. In addition to a tobacco effect on FVC (-131 mL, 95% CI: -245, -17) and FEV1/FVC ratio (42, 95% CI: 1, 83), regression analysis controlling for covariates indicated that for the subsample of children whose mothers were CYP1A1⁎2A homozygous, maternal daily smoking was associated with -734 mL (95% CI: -1206, -262) reductions in FEV1 and -825 mL (95% CI: -909, -795) reductions in FVC; reduced smoking was still associated with -590 mL (95% CI: -629, -551) reductions in FVC. For children of mothers with GSTM1 deletion, persistent daily smoking was associated with -176 mL (95% CI: -305, -47) reductions in FVC.

DISCUSSION AND CONCLUSIONS

Maternal smoking during pregnancy was significantly associated with lung-function reduction in children, particularly for those whose mothers possessed the polymorphic CYP1A1*2A and GSTM1 deletion.

Exposure assessment in cohort studies of childhood asthma

BACKGROUND

The environment is suspected to play an important role in the development of childhood asthma. Cohort studies are a powerful observational design for studying exposure-response relationships, but their power depends in part upon the accuracy of the exposure assessment.

OBJECTIVE

The purpose of this paper is to summarize and discuss issues that make accurate exposure assessment a challenge and to suggest strategies for improving exposure assessment in longitudinal cohort studies of childhood asthma and allergies.

DATA SYNTHESIS

Exposures of interest need to be prioritized, because a single study cannot measure all potentially relevant exposures. Hypotheses need to be based on proposed mechanisms, critical time windows for effects, prior knowledge of physical, physiologic, and immunologic development, as well as genetic pathways potentially influenced by the exposures. Modifiable exposures are most important from the public health perspective. Given the interest in evaluating gene-environment interactions, large cohort sizes are required, and planning for data pooling across independent studies is critical. Collection of additional samples, possibly through subject participation, will permit secondary analyses. Models combining air quality, environmental, and dose data provide exposure estimates across large cohorts but can still be improved.

CONCLUSIONS

Exposure is best characterized through a combination of information sources. Improving exposure assessment is critical for reducing measurement error and increasing power, which increase confidence in characterization of children at risk, leading to improved health outcomes.

Determinants of serum cotinine and hair cotinine as biomarkers of childhood secondhand smoke exposure

Understanding the determinants of childhood secondhand smoke (SHS) exposure is important in measuring and preventing exposure to this widespread environmental contaminant. We evaluated the ability of a broad set of factors to explain variability in serum cotinine, reflecting recent exposure, and hair cotinine, reflecting longer-term exposure. We included repeated measures from 223 elementary-school-age asthmatic children residing with a smoker. We used a manual model-building approach and likelihood ratio tests to select a model predicting each biomarker, and also compared the predictive ability of determinants using Akaike Information Criteria. Potential determinants included a comprehensive parent questionnaire, household nicotine, home ventilation characteristics, exposure in vehicles and others' homes, child demographics, and family social class. Variables in each of these categories remained in the final model for both serum (R(2) of 0.61) and hair cotinine (R(2) of 0.45). A comprehensive set of factors was required to best predict cotinine. Studies should use biomarkers for the best quantitative assessment of SHS exposure. Hair cotinine may be a problematic measure because it was highly influenced by racial differences that were unexplained by SHS exposure. When biospecimen collection is not possible, a household nicotine measurement is warranted. If only questionnaires are available, multiple questions are required to best characterize exposure, such as number of cigarettes, hours spent in a room with concurrent smoking, maternal smoking, and approximate home size.

A descriptive analysis of relations between parents' self-reported smoking behavior and infants' daily exposure to environmental tobacco smoke

BACKGROUND

The aims of the present study were to examine relations between parents' self-reported smoking behavior and infants' daily exposure to environmental tobacco smoke, as assessed by urinary cotinine-to-creatinine ratio (CCR), and to describe the CCR over seven days among infants at home.

METHODS

A convenience sample of 27 households was drawn. Each household had to have at least one daily tobacco smoker and one child up to three years of age. Over a seven-day period, urine samples were obtained from the child daily. To examine relations between parents' self-reported smoking and infants' daily CCR, generalized estimating equation (GEE) analysis was used.

RESULTS

The data revealed that infants from households with indoor smoking had higher CCRs than infants in households with outdoor smoking. CCRs were higher in girls than in boys. Older infants had lower CCRs than younger infants. Smoking outside the home versus inside the home, infant's gender, and infants' age accounted for 68% of the variance in CCR in a GEE data analysis model. No increase or decrease of CCR over time was found.

CONCLUSION

The findings suggest that parents' self-reported smoking indoors at home versus outdoors is predictive of CCR among infants three and younger. Higher CCR concentrations in girls' urine need further examination. Furthermore, significant fluctuations in daily CCR were not apparent in infants over a seven-day time period.

Measurement of tobacco smoke exposure: comparison of toenail nicotine biomarkers and self-reports

BACKGROUND

Accurate measurement tools of exposure for use in large epidemiologic studies are lacking. Biomarkers of tobacco exposure provide additional advantages to self-reports and there is a need to further develop and validate them. The objective is to compare toenail nicotine levels, a novel biomarker of tobacco exposure, with self-reports of tobacco exposure from a large cohort study.

METHODS

In this cross-sectional analysis, toenail samples were collected from 2,485 women participating in the Nurses' Health Study in 1982. Detailed self-reports of smoking habits and reported exposure to secondhand smoke (SHS) were collected from these women near the time of toenail collection. The toenail samples were analyzed by a high-performance liquid chromatography method for measuring nicotine.

RESULTS

The 5 to 95 percentile range of toenail nicotine was from 0.06 to 4.06 ng/mg toenail and the median level was 0.21 ng/mg. There was a significant difference in toenail nicotine levels according to reported smoking status (the median level for nonsmokers with no SHS was 0.10 ng/mg, the median level for nonsmokers with SHS was 0.14 ng/mg, and the median level for active smokers was 1.77 ng/mg). However there was considerable overlap in nicotine levels according to reported smoking status. Toenail nicotine level was strongly associated with reported smoking level (Spearman r = 0.63), but there was no complete concordance, suggesting that the two methods are measuring different aspects of the same exposure.

CONCLUSION

Our findings show that toenail nicotine levels capture the overall burden of tobacco smoke exposure and provide additional information on exposure not captured by reported history.

Fetal exposure to secondhand tobacco smoke assessed by maternal self-reports and cord blood cotinine: prospective cohort study in Krakow

OBJECTIVES

While the validity of self-reported smoking habits is generally judged as satisfactory, objective markers of secondhand smoke (SHS) exposure may be more useful in validating the causal links between prenatal SHS and health effects. The cohort study in Krakow provided an opportunity for comparative assessment of fetal exposure to SHS based upon questionnaires and cord blood cotinine measurements.

METHODS

The study sample included 467 newborns born to women recruited in the first and second trimester of pregnancy. To compare the validity of self-reported SHS and cord blood cotinine levels in assessing the association between fetal passive smoking and health effects of newborns, we separately examined the regression coefficients of birthweight on self-reported number of cigarettes smoked by other household members during the entire pregnancy and cord blood cotinine levels.

RESULTS

In the non-exposed newborns the geometric mean of cord blood cotinine was 0.077 ng/ml and was significantly lower than in newborns with a maternal report of SHS. Cord cotinine levels were more highly correlated with a self-reported number of cigarettes smoked daily at home in the third trimester of pregnancy. The two measures of SHS (number of cigarettes and number of hours of daily exposure) were equally well correlated with cord blood cotinine levels. Using cotinine as the exposure variable, overall the association was not significant; but among the subgroup with cord cotinine levels above the median (> or =0.083 ng/ml), the association with birthweight was significant (beta coefficient = -113.65, P = 0.041).

CONCLUSION

The study provides evidence that the assessment of fetal SHS exposure based on cord blood cotinine produced better estimates of the association between exposure and birth outcomes.

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 < or = 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.

Exposure to fine and ultrafine particles from secondhand smoke in public places before and after the smoking ban, Italy 2005

BACKGROUND

A smoking ban in all indoor public places was enforced in Italy on 10 January 2005.

METHODS

We compared indoor air quality before and after the smoking ban by monitoring the indoor concentrations of fine (<2.5 microm diameter, PM2.5) and ultrafine particulate matter (<0.1 microm diameter, UFP). PM2.5 and ultrafine particles were measured in 40 public places (14 bars, six fast food restaurants, eight restaurants, six game rooms, six pubs) in Rome, before and after the introduction of the law banning smoking (after 3 and 12 months). Measurements were taken using real time particle monitors (DustTRAK Mod. 8520 TSI; Ultra-fine Particles Counter-TRAK Model 8525 TSI). The PM2.5 data were scaled using a correction equation derived from a comparison with the reference method (gravimetric measurement). The study was completed by measuring urinary cotinine, and pre-law and post-law enforcement among non-smoking employees at these establishments

RESULTS

In the post-law period, PM2.5 decreased significantly from a mean concentration of 119.3 microg/m3 to 38.2 microg/m3 after 3 months (p<0.005), and then to 43.3 microg/m3 a year later (p<0.01). The UFP concentrations also decreased significantly from 76,956 particles/cm3 to 38,079 particles/cm3 (p<0.0001) and then to 51,692 particles/cm3 (p<0.01). Similarly, the concentration of urinary cotinine among non-smoking workers decreased from 17.8 ng/ml to 5.5 ng/ml (p<0.0001) and then to 3.7 ng/ml (p<0.0001).

CONCLUSION

The application of the smoking ban led to a considerable reduction in the exposure to indoor fine and ultrafine particles in hospitality venues, confirmed by a contemporaneous reduction of urinary cotinine.

4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides in the urine of infants exposed to environmental tobacco smoke

Biomarkers of carcinogen uptake could provide important information pertinent to the question of exposure to environmental tobacco smoke (ETS) in childhood and cancer development later in life. Previous studies have focused on exposures before birth and during childhood, but carcinogen uptake from ETS in infants has not been reported. Exposures in infants could be higher than in children or adults because of their proximity to parents who smoke. Therefore, we quantified 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL) in the urine of 144 infants, ages 3 to 12 months, who lived in homes with parents who smoked. Total NNAL is an accepted biomarker of uptake of the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. Cotinine and its glucuronide (total cotinine) and nicotine and its glucuronide (total nicotine) were also quantified. Total NNAL was detectable in 67 of 144 infants (46.5%). Mean levels of total NNAL in the 144 infants were 0.083 +/- 0.200 pmol/mL, whereas those of total cotinine and total nicotine were 0.133 +/- 0.190 and 0.069 +/- 0.102 nmol/mL, respectively. The number of cigarettes smoked per week in the home or car by any family member when the infant was present was significantly higher (P < 0.0001) when NNAL was detected than when it was not (76.0 +/- 88.1 versus 27.1 +/- 38.2). The mean level of NNAL detected in the urine of these infants was higher than in most other field studies of ETS exposure. The results of this study show substantial uptake of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in infants exposed to ETS and support the concept that persistent ETS exposure in childhood could be related to cancer later in life.

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.

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.

Household characteristics, smoking bans, and passive smoke exposure in young children

INTRODUCTION

Young children are vulnerable to the health effects of environmental tobacco smoke (ETS) exposure in their own homes. Characteristics of households and the use of smoking bans (i.e., no smoking allowed) as an indicator of smoke exposure need to be understood before interventions can be developed to eliminate ETS exposure in homes where young children live.

METHODS

This cross-sectional, descriptive study investigated demographic characteristics, knowledge, attitudes/beliefs, health of children, smoking practices, and the presence of smoking bans in households. A survey questionnaire was administered to a convenience sample of 226 English- and Spanish-speaking subjects, 18 to 50 years of age, including both smokers and nonsmokers. Cotinine levels of urine samples from children measured actual smoke exposure to confirm reports of home smoking policies.

RESULTS

Ethnicity of households (P < .001) and negative attitudes toward smoke exposure (P < .001) predicted the presence of smoking bans. The number of households with no or partial smoking bans correlated significantly with urine cotinine levels (r = .486); the presence of no or partial smoking bans predicted smoke exposure in households.

DISCUSSION

Because the use of smoking bans in predicting household smoke exposure has not been previously demonstrated, further study is needed to determine how smoking bans can be utilized to eliminate or reduce smoke exposure in homes where children live.

Parent reported home smoking bans and toddler (18-30 month) smoke exposure: a cross-sectional survey

AIMS

To study the relation between the use of parent reported home smoking bans and smoke exposure among children aged 18-30 months.

METHODS

A total of 309 smoking households with children aged 18-30 months, who were part of the Coventry Cohort study, consented to participate in this cross-sectional survey.

RESULTS

Although parents in almost 88% of smoking households reported using harm reduction strategies to protect their toddlers from smoke exposure, only 13.9% reported smoking bans in the house. Mean log urinary cotinine:creatinine ratio was significantly lower for those children whose parents reported no smoking in the house (1.11, 95% CI 0.64 to 1.49) compared with none/less strict strategies (1.87, 95% CI 1.64 to 2.10). In linear regression models fitted on log cotinine:creatinine ratio, no smoking in the house was independently associated with a significant reduction in cotinine:creatinine ratio (B = -0.55, 95% CI -0.89 to -0.20) after adjusting for mother's and partner's average daily cigarette consumption, housing tenure, and overcrowding. The final model accounted for 44.3% of the variance.

CONCLUSIONS

Not smoking in the house was associated with a reduction in mean urinary cotinine:creatinine ratio in children aged 18-30 months; the relation persisted after adjustment for levels of mother's and partner's daily cigarette consumption and sociodemographic factors. Results suggest that home smoking bans in this age group have a small but significant effect on smoke exposure independent of levels of parental tobacco consumption.

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.

Questionnaires for the Measurement of Infant Environmental Tobacco Smoke Exposure: A Systematic Review

A necessary prerequisite for reducing infant morbidity associated with passive smoking is effective measurement of this health risk factor. The purpose of this review was to evaluate questionnaires currently used in research to measure infant environmental tobacco smoke (ETS) exposure. Systematic searches were conducted using MEDLINE and CINAHL databases to identify current studies of infant ETS exposure. Sixty research reports published between 1996 and 2002 met the selection criteria. All of these investigations used brief investigator-developed, parental self-reports; no two studies used the same questionnaire. Reliability testing for questionnaires was lacking. Preliminary support for concurrent and construct validity is presented. Nursing studies are needed that lead to the development of ETS exposure questionnaires with established reliability and validity that measure both risk and protective mechanisms that occur in the infant environment.

Effect of strategies to reduce exposure of infants to environmental tobacco smoke in the home: cross sectional survey

OBJECTIVE

To examine parents' reported knowledge and use of harm reduction strategies to protect their infants from exposure to tobacco smoke in the home, and the relation between reported use of strategies and urinary cotinine to creatinine ratios in the infants.

DESIGN

Cross sectional survey.

SETTINGS

Coventry and Birmingham.

MAIN OUTCOME MEASURES

Parents' reported knowledge and use of harm reduction strategies and urinary cotinine to creatinine ratios in their infants.

PARTICIPANTS

314 smoking households with infants.

RESULTS

86% of parents (264/307) believed that environmental tobacco smoke is harmful, 90% (281/314) believed that infants can be protected from it in the home, and 10% (32/314) were either unaware of measures or reported using none. 65% of parents (205/314) reported using two or more measures, but only 18% (58/314) reported not allowing smoking in the home. No difference was found in mean log e transformed urinary cotinine to creatinine ratio in infants from households that used no measures compared with households that used less strict measures. Mean log cotinine to creatinine ratios were significantly different in households banning smoking in the home compared with those using less strict or no measures. Banning smoking in the home was independently associated with a significant reduction in urinary cotinine to creatinine ratio by a factor of 2.6 (1.6 to 4.2) after adjustment for average household cigarette consumption, tenure, and overcrowding.

CONCLUSIONS

Less than a fifth of parents in smoking households ban smoking in the home. Banning smoking was associated with a small but significant reduction in urinary cotinine to creatinine ratio in infants, whereas less strict measures compared with no measures had no effect on the infants' exposure to environmental tobacco smoke.

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.

Hair as a biomarker for exposure to tobacco smoke

This article provides an overview of the hair nicotine biomarker for assessment of exposure to tobacco smoke, with emphasis on environmental tobacco smoke (ETS). Measurement of nicotine in hair can be an informative tool for research looking at ETS and related illnesses. There are still unresolved issues in relation to this biomarker such as influence of hair treatment, hair colour, and growth rate on nicotine levels in hair, which need to be addressed in order to further refine this biomarker for exposure assessment. Nevertheless, hair nicotine promises to be a valid and reliable measure of longer term exposure that can be readily applied in epidemiological studies of exposure to tobacco smoke, and more specifically ETS, and its risk to health.

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.

Is the hair nicotine level a more accurate biomarker of environmental tobacco smoke exposure than urine cotinine?

STUDY OBJECTIVE

The aim of this study was to compare the two biomarkers of exposure to environmental tobacco smoke (ETS); urine cotinine and hair nicotine, using questionnaires as the standard.

DESIGN

A cross sectional study of children consecutively admitted to hospital for lower respiratory illnesses during the period of the study.

SETTINGS

Three regional hospitals in the larger Wellington area, New Zealand.

PARTICIPANTS

Children aged 3-27 months and admitted to the above hospitals during August 1997 to October 1998. A total of 322 children provided 297 hair samples and 158 urine samples.

MAIN RESULTS

Hair nicotine levels were better able to discriminate the groups of children according to their household's smoking habits at home (no smokers, smoke only outside the home, smoke inside the house) than urine cotinine (Kruskall-Wallis; chi(2)=142.14, and chi(2)=49.5, respectively (p<0.0001)). Furthermore, hair nicotine levels were more strongly correlated with number of smokers in the house, and the number of cigarettes smoked by parents and other members of the child's households. Hair nicotine was better related to the questionnaire variables of smoking in a multivariate regression model (r(2)=0.55) than urine cotinine (r(2)=0.31).

CONCLUSIONS

In this group of young children, hair nicotine was a more precise biomarker of exposure to ETS than urine cotinine levels, using questionnaire reports as the reference. Both biomarkers indicate that smoking outside the house limits ETS exposure of children but does not eliminate it.

Emprego da determinação de monóxido de carbono no ar exalado para a detecção do consumo de tabaco

Introdução: O tabagismo é o principal fator de risco prevenível de morbidade e mortalidade em países desenvolvidos e está em ascensão nos países em desenvolvimento. Apesar deste fato, e do maior conhecimento sobre seus efeitos, a prevalência de tabagistas continua elevada. Com o objetivo de comparar o valor de monóxido de carbono no ar exalado (COex) entre indivíduos fumantes e não fumantes, avaliar fatores que influenciam estes valores entre os que fumam e também avaliar a possível influência do tabagismo passivo, foram medidos níveis de COex em funcionários e pacientes do Instituto do Coração HC-FMUSP. Materiais e métodos: Este estudo transversal incluiu 256 voluntários que responderam a um questionário e foram submetidos à mensuração de COex em aparelho micromedidor de CO. Resultados: Dos entrevistados, 106 eram do sexo masculino e 150 do feminino e a idade média foi de 43,4 anos (Vmin-max: 15-83). 107 informaram ser tabagistas, 118 não fumantes e 31 fumantes passivos. A média de COex dos fumantes foi de 14,01ppm (Vmin-max: 1-44), dos fumantes passivos 2,03ppm (Vmin-max: 0-5) e, dos não fumantes, 2,50ppm (Vmin-max: 0-9). Houve diferença estatisticamente significante ente o grupo de fumantes e os demais (p < 0,001), mas não entre os fumantes passivos e os não fumantes. Foi encontrada correlação positiva entre número de cigarros fumados por dia e valores de COex e negativa entre o intervalo após ter fumado o último cigarro e o valor de COex. Para um valor de corte de COex igual a 6ppm, foram encontradas sensibilidade de 77% e especificidade de 96%. Conclusão: A mensuração de COex constitui-se um indicador de fácil emprego, baixo custo, não invasivo e que permite a obtenção de resultado imediato, com o valor de corte de COex de 6ppm apresentando boa especificidade para aferir o hábito tabágico.

Infant exposure to environmental tobacco smoke: a prevalence study in Australia

OBJECTIVE

To determine: the prevalence of exposure to environmental tobacco smoke among infants aged 0-12 months in two child health care settings; the accuracy of parent report indicators of exposure; and the factors associated with exposure to environmental tobacco smoke.

METHOD

Samples of consecutive parents of infants 12 months of age or younger who attended Hunter Region public child health and immunisation clinics were approached to complete a questionnaire and to allow a urine sample to be obtained from their infant during December and January 1998/99. Infant urine samples were analysed for cotinine and information obtained regarding the smoking status of household members, infant exposure to environmental tobacco smoke during the previous three days, and parent and infant characteristics and demographics.

RESULTS

85 (47%) [95% CI 40-54] infants in the combined sample had detectable levels of cotinine. Sensitivity of reported infant exposure of 86% was achieved through the combined measure of parent report of exposure and smoking status of households. The odds of exposure for infants of smoking parents were 14 times that of infants of nonsmokers [CI 5.26-50.0].

CONCLUSIONS

Almost half of the infants in this study had detectable levels of cotinine in their urine. Future interventions targeting infant exposure to environmental tobacco smoke should incorporate quit smoking strategies for both parents and other household members, as well as strategies for changing the pattern of smoking behaviour around infants.

IMPLICATIONS

These findings suggest that existing community education strategies and passive smoking public policies are failing to protect this vulnerable population group.

Passive smoking in children: effect of avoidance strategies, at home as measured by hair nicotine levels

Hair nicotine levels were studied among children, relative to their caregivers' reported exposure to environmental tobacco smoke. A total of 117 children, aged 3 months to 10 years, were recruited consecutively from hospital inpatients, and their respective parents or caregivers were interviewed. Degree of exposure to environmental tobacco smoke was assessed via questionnaire. Scalp hair samples were collected from children and were assayed for nicotine. Levels of nicotine in hair among children reportedly exposed to smokers were higher than levels among unexposed children (chi2 = 26.46, p < .0001). In addition, hair nicotine levels were higher among children with mothers who smoked, compared with those whose mothers did not smoke. Whether household members smoked outside or inside the house had no significant effect on hair nicotine levels of children. Hair nicotine levels differed between children who were reportedly unexposed to environmental tobacco smoke at home and those who were exposed. Smoking outside the home, as reported by parents, did not cause a reduction in nicotine levels in the hair of children.

Epidemiology of otitis media onset by six months of age

OBJECTIVE

Although early otitis media (OM) onset predicts later recurrent and chronic OM, little research has been directed at illuminating the role of prenatal exposures in early OM. This prospective study examined prenatal, innate, and early environmental exposures associated with acute otitis media (AOM) onset and recurrent OM (ROM) by age 6 months.

DESIGN AND METHODS

Prospective study of 596 infants from a health maintenance organization followed from birth to 6 months. Mothers completed monthly forms on prenatal exposures (diet, medications, and illnesses) and infant risk factors (eg, smoke exposure and child care) during pregnancy and until infants were 6 months old. Urine samples were collected when infants were 2 months of age and analyzed for cotinine and creatinine. Physicians and nurse practitioners examined infants at each clinic visit and completed standard ear examination forms.

RESULTS

Thirty-nine percent had an episode of AOM and 20% had ROM by age 6 months. Using Cox's regression models to control for confounding, respiratory tract infection (relative risk [RR] 7.5), day care (RR 1. 7), >1 sibling (RR 1.4), maternal, paternal, and sibling OM history (RR 1.6, 1.5, and 1.7, respectively) were significantly related to early OM onset. ROM was related to respiratory tract infection (RR 9. 5), day care (RR 1.9), conjunctivitis (RR 2.0), maternal OM history (RR 1.9), and birth in the fall (RR 2.6). Among prenatal exposures, only high prenatal dietary vitamin C intake was significantly inversely related to early AOM with univariate but not multivariate analysis.

CONCLUSION

Prenatal factors were not linked to early AOM onset with multivariate analysis, but environmental and innate factors play an important role in early AOM onset. Strategies to reduce exposure to environmental variables could reduce rates of early AOM, which could potentially result in declining rates of ROM and chronic OME.