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1.  Factors Associated with Second Hand Smoke Exposure In Young Inner City Children with Asthma 
To examine the association of social and environmental factors with levels of second hand smoke (SHS) exposure, as measured by salivary cotinine, in young inner city children with asthma.
We used data drawn from a home-based behavioral intervention for young high risk children with persistent asthma post emergency department (ED) treatment (N=198). SHS exposure was measured by salivary cotinine and caregiver report. Caregiver demographic and psychological functioning, household smoking behavior and asthma morbidity were compared with child cotinine concentrations. Chi-square and ANOVA tests and multivariate regression models were used to determine the association between cotinine concentrations with household smoking behavior and asthma morbidity.
Over half (53%) of the children had cotinine levels compatible with SHS exposure and mean cotinine concentrations were high at 2.42 ng/ml (SD 3.2). The caregiver was the predominant smoker in the home (57%) and (63%) reported a total home smoking ban. Preschool age children, and those with caregivers reporting depressive symptoms and high stress had higher cotinine concentrations than their counterparts. Among children living in a home with a total home smoking ban, younger children had significantly higher mean cotinine concentration than older children (Cotinine: 3–5 year olds, 2.24 ng/ml (SD 3.5); 6–10 year olds, 0.63 ng/ml (SD 1.0); p <0.05). In multivariate models, the factors most strongly associated with high child cotinine concentrations were increased number of household smokers (β = 0.24) and younger child age (3–5 years) (β = 0.23; P <0.001, R2 = 0.35).
Over half of young inner-city children with asthma were exposed to second hand smoke and caregivers are the predominant household smoker. Younger children and children with depressed and stressed caregivers are at significant risk of smoke exposures, even when a household smoking ban is reported. Further advocacy for these high-risk children is needed to help caregivers quit and to mitigate smoke exposure.
PMCID: PMC3113681  PMID: 21545248
asthma; children; cotinine; second hand smoke
2.  Screening for Environmental Tobacco Smoke Exposure among Inner City Children with Asthma 
Pediatrics  2008;122(6):1277-1283.
Environmental tobacco smoke (ETS) causes increased morbidity among children with asthma, however pediatricians do not consistently screen and counsel families of asthmatic children regarding ETS. An index score based on parent report of exposure could help providers efficiently screen for ETS.
1) To develop an index measure of ETS based on parent self-report of smoking behaviors; 2) To determine whether the index score is associated with children’s present and future cotinine levels.
Data were drawn from a community intervention for inner-city children with persistent asthma (n=226, response rate 72%). Measures of child salivary cotinine and parent self-reported ETS-related behaviors were obtained at baseline and 7–9 months later. To develop the index score, we used a 15-fold cross-validation method on 70% of our data that considered combinations of smoke exposure variables, controlling for demographics. We chose the most parsimonious model that minimized the mean square predictive error. The resulting index score included primary caregiver smoking and home smoking ban status. We validated our model on the remaining 30% of data. ANOVA and multivariate analyses were used to determine the association of the index score with children’s cotinine levels.
54% of asthmatic children lived with ≥1 smoker and 51% of caregivers reported a complete home smoking ban. The children’s mean baseline cotinine was 1.55ng/ml (range 0.0–21.3). Children’s baseline and follow-up cotinine levels increased as scores on the index measure increased. In a linear regression, the index score was significantly and positively associated with children’s cotinine measurements at baseline (p<.001, model R2=.37) and 7–9 months later (p<.001, R2=.38).
An index measure with combined information regarding primary caregiver smoking and household smoking restrictions helps to identify asthmatic children with the greatest exposure to ETS, and can predict children who will have elevated cotinine levels 7–9 months later.
PMCID: PMC2597221  PMID: 19047246
Environmental tobacco smoke; asthma; children; primary care; screening
3.  Environmental Tobacco Smoke and Behaviors of Inner-City Children With Asthma 
To explore the relationship between environmental tobacco smoke (ETS) exposure and behavior among inner-city children with significant asthma.
We analyzed baseline data for 200 children 4 to 10 years old who were enrolled in an asthma program. Environmental tobacco smoke exposure was measured by the child’s salivary cotinine level. Caregivers completed the 28-item Behavior Problem Index (BPI). Positive responses were summed for a total BPI score, and children with scores >14 were considered to have significant behavior problems. We conducted Student t tests and multivariate regression analyses to determine the association of children’s cotinine levels with BPI scores.
Overall, 56% of children were male, 65% were black, and 72% had Medicaid. Mean cotinine level was 1.47 ng/mL. Overall, 30% of children had total BPI scores >14. Children with cotinine values >1.47 ng/mL had significantly higher scores compared with children with lower cotinine values on total BPI (12.5 vs 10.2), as well as externalizing (9.0 vs 7.2), antisocial (2.3 vs 1.7), and immature (2.1 vs 1.6) subscales. In a multivariate model, log cotinine remained independently associated with externalizing (P = .04), headstrong (P = .04), and antisocial behavior (P = .04).
Cotinine levels are independently associated with problem behaviors among this sample of urban children with asthma.
PMCID: PMC2597107  PMID: 18922501
behavior; childhood asthma; environmental smoke exposure; inner-city
4.  Lung function, asthma symptoms, and quality of life for children in public housing in Boston: a case-series analysis 
Environmental Health  2004;3:13.
Children in urban public housing are at high risk for asthma, given elevated environmental and social exposures and suboptimal medical care. For a multifactorial disease like asthma, design of intervention studies can be influenced by the relative prevalence of key risk factors. To better understand risk factors for asthma morbidity in the context of an environmental intervention study, we conducted a detailed baseline evaluation of 78 children (aged 4–17 years) from three public housing developments in Boston.
Asthmatic children and their caregivers were recruited between April 2002 and January 2003. We conducted intake interviews that captured a detailed family and medical history, including questions regarding asthma symptom severity, access to health care, medication usage, and psychological stress. Quality of life was evaluated for both the child and caregiver with an asthma-specific scale. Pulmonary function was measured with a portable spirometer, and allergy testing for common indoor and outdoor allergens was conducted with skin testing using the prick puncture method. Exploratory linear and logistic regression models evaluating predictors of respiratory symptoms, quality of life, and pulmonary function were conducted using SAS.
We found high rates of obesity (56%) and allergies to indoor contaminants such as cockroaches (59%) and dust mites (59%). Only 36% of children with persistent asthma reported being prescribed any daily controller medication, and most did not have an asthma action plan or a peak flow meter. One-time lung function measures were poorly correlated with respiratory symptoms or quality of life, which were significantly correlated with each other. In multivariate regression models, household size, body mass index, and environmental tobacco smoke exposure were positively associated with respiratory symptom severity (p < 0.10). Symptom severity was negatively associated with asthma-related quality of life for the child and the caregiver, with caregiver (but not child) quality of life significantly influenced by caregiver stress and whether the child was in the intensive care unit at birth.
Given the elevated prevalence of multiple risk factors, coordinated improvements in the social environment, the built environment, and in medical management would likely yield the greatest health benefits in this high-risk population.
PMCID: PMC544563  PMID: 15585065
5.  Does passive smoking increase the frequency of health service contacts in children with asthma? 
Thorax  2001;56(1):9-12.
BACKGROUND—Passive smoking is a major cause of respiratory morbidity in children. However, few studies give accurate estimates of the health effects of passive smoking in children with asthma using an objective measure of exposure. The effects of passive smoking using salivary cotinine levels to measure exposure were investigated.
METHODS—A sample of 438 children aged 2-12 years with asthma who had a parent who smoked were recruited in Tayside and Fife, Scotland. Health service contacts for asthma, assessed from GP case records, were used as a proxy for morbidity.
RESULTS—A weak U-shaped relationship was found between the salivary cotinine level and health service contacts for asthma: compared with low cotinine levels those with moderate cotinine levels had a reduced contact rate (relative rate (RR) = 0.91, 95% confidence interval (CI) 0.80 to 1.05), whereas high cotinine levels were associated with an increased rate of contact (RR = 1.19, 95% CI 1.05 to 1.37). In contrast, a strong association was seen with the amount the parent reported smoking in front of the child: the higher the level the fewer visits were made for asthma (RR for everyday exposure = 0.66, 95% CI 0.56 to 0.77). This effect was not seen for non-respiratory visits. Demographic factors, age of child, and number of children in the family all had a powerful effect on the number of visits for asthma. The parents' perception of asthma severity was associated with visit frequency independent of actual severity (derived from drug treatment).
CONCLUSION—High levels of parental smoking in the home are associated with a reduction in health care contacts for asthma. This could be due to a lack of awareness of asthma symptoms among heavy smokers or a reluctance to visit the GP. Children with asthma who have parents who smoke heavily may not be receiving adequate management.

PMCID: PMC1745908  PMID: 11120897
6.  Households contaminated by environmental tobacco smoke: sources of infant exposures 
Tobacco Control  2004;13(1):29-37.
Objectives: To examine (1) whether dust and surfaces in households of smokers are contaminated with environmental tobacco smoke (ETS); (2) whether smoking parents can protect their infants by smoking outside and away from the infant; and (3) whether contaminated dust, surfaces, and air contribute to ETS exposure in infants.
Design: Quasi-experiment comparing three types of households with infants: (1) non-smokers who believe they have protected their children from ETS; (2) smokers who believe they have protected their children from ETS; (3) smokers who expose their children to ETS.
Setting: Homes of smokers and non-smokers.
Participants: Smoking and non-smoking mothers and their infants ⩽ 1 year.
Main outcome measures: ETS contamination as measured by nicotine in household dust, indoor air, and household surfaces. ETS exposure as measured by cotinine levels in infant urine.
Results: ETS contamination and ETS exposure were 5–7 times higher in households of smokers trying to protect their infants by smoking outdoors than in households of non-smokers. ETS contamination and exposure were 3–8 times higher in households of smokers who exposed their infants to ETS by smoking indoors than in households of smokers trying to protect their children by smoking outdoors.
Conclusions: Dust and surfaces in homes of smokers are contaminated with ETS. Infants of smokers are at risk of ETS exposure in their homes through dust, surfaces, and air. Smoking outside the home and away from the infant reduces but does not completely protect a smoker's home from ETS contamination and a smoker's infant from ETS exposure.
PMCID: PMC1747815  PMID: 14985592
7.  Asthma and the home environment of low-income urban children: Preliminary findings from the seattle-king county healthy homes project 
Childhood asthma is a growing public health concern in low-income urban communities. Indoor exposure to asthma triggers has emerged as an important cause of asthma exacerbations. We describe indoor environmental conditions related to asthma triggers among a low-income urban population in Seattle/King County, Washington, as well as caregiver knowledge and resources related to control of these triggers.
Data are obtained from in-person, structured, closed-end interviews with the caretakers of children aged 4–12 years with persistent asthma living in households with incomes less than 200% of poverty. Additional information is collected during a home inspection. The children and their caregivers are participants in the ongoing Seattle-King County Healthy Homes Project, a randomized controlled trial of an intervention to empower low-income families to reduce exposure to indoor asthma triggers. We report findings on the conditions of the homes prior to this intervention among the first 112 enrolled households.
A smoker was present in 37.5% of homes. Mold was visible in 26.8% of homes, water damage was present in 18.6% of homes, and damp conditions occurred in 64.8% of households, while 39.6% of caregivers were aware that excessive moisture can increase exposures to allergens. Dust-trapping reservoirs were common; 76.8% of children's bedrooms had carpeting. Cockroach infestation in the past 3 months was reported by 23.4% of caregivers, while 57.1% were unaware of the association of roaches and asthma. Only 19.8% of the children had allergy-control mattress covers.
Many low-income urban children with asthma in King County live in indoor environments that place them at substantial risk of ongoing exposure to asthma triggers. Substandard housing and lack of resources often underlie these exposures. Initiatives involving health educators, outreach workers, medical providers, health care insurers, housing agencies, and elected officials are needed to reduce these exposures.
PMCID: PMC3456608  PMID: 10741842
Asthma; Child; Indoor Air Pollution; Indoor Environment; Knowledge/Behaviors; Low-Income Populations
8.  Relation of passive smoking as assessed by salivary cotinine concentration and questionnaire to spirometric indices in children. 
Thorax  1993;48(1):14-20.
BACKGROUND: Previous studies of the effects of passive exposure to smoke on spirometric indices in children have largely relied on questionnaire measures of exposure. This may have resulted in underestimation of the true effect of passive smoking. Biochemical measures offer the opportunity to estimate recent exposure directly. METHODS: The relation between spirometric indices and passive exposure to tobacco smoke was examined in a large population sample of 5-7 year old children from 10 towns in England and Wales. The effects of passive exposure to smoke on lung function were assessed by means of both salivary cotinine concentration and questionnaire measurements of exposure. Analyses of the relation between spirometric values and cotinine concentrations were based on 2511 children and of the relation between spirometric values and questionnaire measures on 2000 children. RESULTS: Cotinine concentration was negatively associated with all spirometric indices after adjustment for confounding variables, which included age, sex, body size, and social class. The strongest association was with mid expiratory flow rate (FEF50), the fall between the bottom and top fifths of the cotinine distribution being 6%, equivalent to a reduction of 14.3 (95% confidence limits (CL) 8.6, 20.0) ml/s per ng/ml cotinine. Salivary cotinine concentrations were strongly related to exposure to cigarette smoke at home but 88% of children who were from non-smoking households and not looked after by a smoker had detectable cotinine concentrations, 5% being in the top two fifths of the cotinine distribution. A composite questionnaire score based on the number of regular sources of exposure was as strongly related to mid and end expiratory flow rates as the single cotinine measure. The fall in FEF50 per smoker to whom the child was exposed was 51.0 (26.5, 75.5) ml/s. The relationships between the questionnaire score and forced vital capacity (FVC) or forced expiratory volume in one second (FEV1) were not statistically significant. CONCLUSIONS: These effects of passive smoking on respiratory function are consistent with the results of previous studies and, although small in absolute magnitude, may be important if the effects of exposure are cumulative. In children aged 5-7 years the use of a single salivary cotinine concentration as a marker of passive exposure to smoke resulted in clear relationships between exposure and FVC and FEV1, whereas the associations were much weaker and not significant when based on the questionnaire score. The associations between exposure and mid or end expiratory flow rates were of similar magnitude for cotinine concentration and the questionnaire score. The use of salivary cotinine concentration in longitudinal studies may help to determine the extent to which these effects are cumulative or reversible.
PMCID: PMC464228  PMID: 8434347
9.  What determines levels of passive smoking in children with asthma? 
Thorax  1997;52(9):766-769.
BACKGROUND: Children with parents who smoke are often exposed to high levels of environmental tobacco smoke, and children with asthma are particularly susceptible to the detrimental effects of passive smoking. Data were collected from parents who smoke and from their asthmatic children. The families are currently taking part in a randomised controlled trial to test an intervention designed to reduce passive smoking in children with asthma. This paper reports on the baseline data. Questionnaire data and cotinine levels were compared in an attempt to assess exposure and to identify factors which influence exposure of the children. The aim of the study was to identify the scope for a reduction in passive smoking by these children. METHODS: A sample of 501 families with an asthmatic child aged 2-12 years was obtained. Factors influencing passive smoking were assessed by interviewing parents. Cotinine levels were measured from saliva samples using gas liquid chromatography with nitrogen phosphorous detection. RESULTS: Cotinine levels in children were strongly associated with the age of the child, the number of parents who smoked, contact with other smokers, the frequency of smoking in the same room as the child, and crowding within the home. Parental cotinine levels, the amount smoked in the home, and whether the home had a garden also exerted an independent effect on cotinine levels in the children. CONCLUSIONS: Many children are exposed to high levels of environmental tobacco smoke and their cotinine levels are heavily dependent upon proximity to the parent who smokes. Parents who smoke have a unique opportunity to benefit their child's health by modifying their smoking habits within the home. 

PMCID: PMC1758643  PMID: 9371205
10.  Association of Maternal Smoking With Child Cotinine Levels 
Nicotine & Tobacco Research  2013;15(12):2029-2036.
Our aim was to understand the strength of association between parental smoking and child environmental tobacco smoke (ETS) exposure in order to inform the development of future tobacco control policies. ETS was measured using child cotinine levels below the active smoking threshold.
Participants were drawn from the Avon Longitudinal Study of Parents and Children and included 3,128 participants at age 7 years and 1,868 participants at age 15 years. The primary outcome was cotinine levels of nonsmoking children, to investigate the relationship between maternal smoking and child cotinine levels. The secondary outcome was cotinine levels of all individuals to investigate the relationship between child smoking and child cotinine levels. Maternal and child smoking behavior was assessed by self-report questionnaire. We adjusted for several sociodemographic variables.
We found an association between maternal smoking and child cotinine at age 7 years (mean cotinine = 1.16ng/ml serum, ratio of geometric means = 3.94, 95% CI = 2.86–5.42) and at age 15 years (mean cotinine = 0.94ng/ml serum, ratio of geometric means = 5.26, 95% CI = 3.06–9.03), after adjustment for potential confounders.
The magnitude of this association for children whose mothers were heavy smokers was comparable with the quantity of half the levels of cotinine observed among children who were irregular (i.e., nonweekly) active smokers, and it was greater than five times higher than that seen in nonsmoking children whose mothers didn’t smoke. This provides further evidence for the importance of public health interventions to reduce smoking exposure in the home.
PMCID: PMC3819976  PMID: 23880896
11.  Effects of BMI, Fat Mass, and Lean Mass on Asthma in Childhood: A Mendelian Randomization Study 
PLoS Medicine  2014;11(7):e1001669.
In this study, Granell and colleagues used Mendelian randomization to investigate causal effects of BMI, fat mass, and lean mass on current asthma at age 7½ years in the Avon Longitudinal Study of Parents and Children (ALSPAC) and found that higher BMI increases the risk of asthma in mid-childhood.
Please see later in the article for the Editors' Summary
Observational studies have reported associations between body mass index (BMI) and asthma, but confounding and reverse causality remain plausible explanations. We aim to investigate evidence for a causal effect of BMI on asthma using a Mendelian randomization approach.
Methods and Findings
We used Mendelian randomization to investigate causal effects of BMI, fat mass, and lean mass on current asthma at age 7½ y in the Avon Longitudinal Study of Parents and Children (ALSPAC). A weighted allele score based on 32 independent BMI-related single nucleotide polymorphisms (SNPs) was derived from external data, and associations with BMI, fat mass, lean mass, and asthma were estimated. We derived instrumental variable (IV) estimates of causal risk ratios (RRs). 4,835 children had available data on BMI-associated SNPs, asthma, and BMI. The weighted allele score was strongly associated with BMI, fat mass, and lean mass (all p-values<0.001) and with childhood asthma (RR 2.56, 95% CI 1.38–4.76 per unit score, p = 0.003). The estimated causal RR for the effect of BMI on asthma was 1.55 (95% CI 1.16–2.07) per kg/m2, p = 0.003. This effect appeared stronger for non-atopic (1.90, 95% CI 1.19–3.03) than for atopic asthma (1.37, 95% CI 0.89–2.11) though there was little evidence of heterogeneity (p = 0.31). The estimated causal RRs for the effects of fat mass and lean mass on asthma were 1.41 (95% CI 1.11–1.79) per 0.5 kg and 2.25 (95% CI 1.23–4.11) per kg, respectively. The possibility of genetic pleiotropy could not be discounted completely; however, additional IV analyses using FTO variant rs1558902 and the other BMI-related SNPs separately provided similar causal effects with wider confidence intervals. Loss of follow-up was unlikely to bias the estimated effects.
Higher BMI increases the risk of asthma in mid-childhood. Higher BMI may have contributed to the increase in asthma risk toward the end of the 20th century.
Please see later in the article for the Editors' Summary
Editors' Summary
The global burden of asthma, a chronic (long-term) condition caused by inflammation of the airways (the tubes that carry air in and out of the lungs), has been rising steadily over the past few decades. It is estimated that, nowadays, 200–300 million adults and children worldwide are affected by asthma. Although asthma can develop at any age, it is often diagnosed in childhood—asthma is the most common chronic disease in children. In people with asthma, the airways can react very strongly to allergens such as animal fur or to irritants such as cigarette smoke, becoming narrower so that less air can enter the lungs. Exercise, cold air, and infections can also trigger asthma attacks, which can be fatal. The symptoms of asthma include wheezing, coughing, chest tightness, and shortness of breath. Asthma cannot be cured, but drugs can relieve its symptoms and prevent acute asthma attacks.
Why Was This Study Done?
We cannot halt the ongoing rise in global asthma rates without understanding the causes of asthma. Some experts think obesity may be one cause of asthma. Obesity, like asthma, is increasingly common, and observational studies (investigations that ask whether individuals exposed to a suspected risk factor for a condition develop that condition more often than unexposed individuals) in children have reported that body mass index (BMI, an indicator of body fat calculated by dividing a person's weight in kilograms by their height in meters squared) is positively associated with asthma. Observational studies cannot prove that obesity causes asthma because of “confounding.” Overweight children with asthma may share another unknown characteristic (confounder) that actually causes both obesity and asthma. Moreover, children with asthma may be less active than unaffected children, so they become overweight (reverse causality). Here, the researchers use “Mendelian randomization” to assess whether BMI has a causal effect on asthma. In Mendelian randomization, causality is inferred from associations between genetic variants that mimic the effect of a modifiable risk factor and the outcome of interest. Because gene variants are inherited randomly, they are not prone to confounding and are free from reverse causation. So, if a higher BMI leads to asthma, genetic variants associated with increased BMI should be associated with an increased risk of asthma.
What Did the Researchers Do and Find?
The researchers investigated causal effects of BMI, fat mass, and lean mass on current asthma at age 7½ years in 4,835 children enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC, a long-term health project that started in 1991). They calculated an allele score for each child based on 32 BMI-related genetic variants, and estimated associations between this score and BMI, fat mass and lean mass (both measured using a special type of X-ray scanner; in children BMI is not a good indicator of “fatness”), and asthma. They report that the allele score was strongly associated with BMI, fat mass, and lean mass, and with childhood asthma. The estimated causal relative risk (risk ratio) for the effect of BMI on asthma was 1.55 per kg/m2. That is, the relative risk of asthma increased by 55% for every extra unit of BMI. The estimated causal relative risks for the effects of fat mass and lean mass on asthma were 1.41 per 0.5 kg and 2.25 per kg, respectively.
What Do These Findings Mean?
These findings suggest that a higher BMI increases the risk of asthma in mid-childhood and that global increases in BMI toward the end of the 20th century may have contributed to the global increase in asthma that occurred at the same time. It is possible that the observed association between BMI and asthma reported in this study is underpinned by “genetic pleiotropy” (a potential limitation of all Mendelian randomization analyses). That is, some of the genetic variants included in the BMI allele score could conceivably also increase the risk of asthma. Nevertheless, these findings suggest that public health interventions designed to reduce obesity may also help to limit the global rise in asthma.
Additional Information
Please access these websites via the online version of this summary at
The US Centers for Disease Control and Prevention provides information on asthma and on all aspects of overweight and obesity (in English and Spanish)
The World Health Organization provides information on asthma and on obesity (in several languages)
The UK National Health Service Choices website provides information about asthma, about asthma in children, and about obesity (including real stories)
The Global Asthma Report 2011 is available
The Global Initiative for Asthma released its updated Global Strategy for Asthma Management and Prevention on World Asthma Day 2014
Information about the Avon Longitudinal Study of Parents and Children is available
MedlinePlus provides links to further information on obesity in children, on asthma, and on asthma in children (in English and Spanish
Wikipedia has a page on Mendelian randomization (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
PMCID: PMC4077660  PMID: 24983943
12.  A Longitudinal Study of Indoor Nitrogen Dioxide Levels and Respiratory Symptoms in Inner-City Children with Asthma 
Environmental Health Perspectives  2008;116(10):1428-1432.
The effect of indoor nitrogen dioxide concentrations on asthma morbidity among inner-city preschool children is uncertain.
Our goal was to estimate the effect of indoor NO2 concentrations on asthma morbidity in an inner-city population while adjusting for other indoor pollutants.
We recruited 150 children (2–6 years of age) with physician-diagnosed asthma from inner-city Baltimore, Maryland. Indoor air was monitored over a 72-hr period in the children’s bedrooms at baseline and 3 and 6 months. At each visit, the child’s caregiver completed a questionnaire assessing asthma symptoms over the previous 2 weeks and recent health care utilization.
Children were 58% male, 91% African American, and 42% from households with annual income < $25,000; 63% had persistent asthma symptoms. The mean (± SD) in-home NO2 concentration was 30.0 ± 33.7 (range, 2.9–394.0) ppb. The presence of a gas stove and the use of a space heater or oven/stove for heat were independently associated with higher NO2 concentrations. Each 20-ppb increase in NO2 exposure was associated significantly with an increase in the number of days with limited speech [incidence rate ratio (IRR) = 1.15; 95% confidence interval (CI), 1.05–1.25], cough (IRR = 1.10; 95% CI, 1.02–1.18), and nocturnal symptoms (IRR = 1.09; 95% CI, 1.02–1.16), after adjustment for potential confounders. NO2 concentrations were not associated with increased health care utilization.
Higher indoor NO2 concentrations were associated with increased asthma symptoms in preschool inner-city children. Interventions aimed at lowering NO2 concentrations in inner-city homes may reduce asthma morbidity in this vulnerable population.
PMCID: PMC2569107  PMID: 18941590
asthma; indoor pollutants; inner city; nitrogen dioxide; preschool
13.  Racial Differences in Exposure to Environmental Tobacco Smoke among Children 
Environmental Health Perspectives  2004;113(3):362-367.
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 (β = 0.34, p = 0.03) than in white children (β = 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.
PMCID: PMC1253766  PMID: 15743729
African American; asthma; cotinine; ETS; housing
14.  Asthma and allergies in Jamaican children aged 2–17 years: a cross-sectional prevalence survey 
BMJ Open  2012;2(4):e001132.
To determine the prevalence and severity of asthma and allergies as well as risk factors for asthma among Jamaican children aged 2–17 years.
A cross-sectional, community-based prevalence survey using the International Study of Asthma and Allergies in Childhood questionnaire. The authors selected a representative sample of 2017 children using stratified, multistage cluster sampling design using enumeration districts as primary sampling units.
Jamaica, a Caribbean island with a total population of approximately 2.6 million, geographically divided into 14 parishes.
Children aged 2–17 years, who were resident in private households. Institutionalised children such as those in boarding schools and hospitals were excluded from the survey.
Primary and secondary outcome measures
The prevalence and severity of asthma and allergy symptoms, doctor-diagnosed asthma and risk factors for asthma.
Almost a fifth (19.6%) of Jamaican children aged 2–17 years had current wheeze, while 16.7% had self-reported doctor-diagnosed asthma. Both were more common among males than among females. The prevalence of rhinitis, hay fever and eczema among children was 24.5%, 25% and 17.3%, respectively. Current wheeze was more common among children with rhinitis in the last 12 months (44.3% vs 12.6%, p<0.001), hay fever (36.8% vs 13.8%, p<0.001) and eczema (34.1% vs 16.4%, p<0.001). Independent risk factors for current wheeze (ORs, 95% CI) were chest infections in the first year of life 4.83 (3.00 to 7.77), parental asthma 4.19 (2.8 to 6.08), rhinitis in the last 12 months 6.92 (5.16 to 9.29), hay fever 4.82 (3.62 to 6.41), moulds in the home 2.25 (1.16 to 4.45), cat in the home 2.44 (1.66 to 3.58) and dog in the home 1.81 (1.18 to 2.78).
The prevalence of asthma and allergies in Jamaican children is high. Significant risk factors for asthma include chest infections in the first year of life, a history of asthma in the family, allergies, moulds and pets in the home.
Article summary
Article focus
The prevalence of asthma and allergies in both developed and developing countries is continuing to rise.
In some Caribbean countries, asthma is a public health problem associated with high economic costs.
This study determined the prevalence of asthma, allergy symptoms and associated risk factors.
Key messages
We demonstrated that the prevalence of asthma and allergy symptoms among Jamaican children aged 2–17 years is high.
Both the prevalence and severity of asthma symptoms are comparable to that reported among children in high-income countries.
Current wheeze and doctor-diagnosed asthma were more common in males and in children with allergies.
A history of asthma in the family, chest infections in the first year of life, allergies, exposure to moulds and pets in the home were associated with significant risk for asthma.
Identifying children at high risk for asthma and controlling modifiable risk factors is important in reducing the prevalence and morbidity related to asthma.
Strengths and limitations of this study
This is the first national study on asthma and allergies in Jamaica using a nationally representative sample of children with a response rate of 80%.
We used a modified ISAAC protocol in which sampling was done by household rather than by school. Using a population-based sampling strategy; we sampled one child and one adult per household. This approach enabled us to obtain national prevalence estimates for both adults and children in one survey at a reduced cost.
Limitations of this study include the fact that the prevalence of asthma and allergies was based solely on self-reports, no objective measures were done. Also in younger children, caregivers responded to questionnaires.
PMCID: PMC3400072  PMID: 22798254
15.  Association of Adenotonsillectomy with Asthma Outcomes in Children: A Longitudinal Database Analysis 
PLoS Medicine  2014;11(11):e1001753.
Rakesh Bhattacharjee and colleagues use data from a US private health insurance database to compare asthma severity measures in children one year before and one year after they underwent adenotonsillectomy with asthma measures in those who did not undergo adenotonsillectomy.
Please see later in the article for the Editors' Summary
Childhood asthma and obstructive sleep apnea (OSA), both disorders of airway inflammation, were associated in recent observational studies. Although childhood OSA is effectively treated by adenotonsillectomy (AT), it remains unclear whether AT also improves childhood asthma. We hypothesized that AT, the first line of therapy for childhood OSA, would be associated with improved asthma outcomes and would reduce the usage of asthma therapies in children.
Methods and Findings
Using the 2003–2010 MarketScan database, we identified 13,506 children with asthma in the United States who underwent AT. Asthma outcomes during 1 y preceding AT were compared to those during 1 y following AT. In addition, 27,012 age-, sex-, and geographically matched children with asthma without AT were included to examine asthma outcomes among children without known adenotonsillar tissue morbidity. Primary outcomes included the occurrence of a diagnostic code for acute asthma exacerbation (AAE) or acute status asthmaticus (ASA). Secondary outcomes included temporal changes in asthma medication prescriptions, the frequency of asthma-related emergency room visits (ARERs), and asthma-related hospitalizations (ARHs). Comparing the year following AT to the year prior, AT was associated with significant reductions in AAE (30.2%; 95% CI: 25.6%–34.3%; p<0.0001), ASA (37.9%; 95% CI: 29.2%–45.6%; p<0.0001), ARERs (25.6%; 95% CI: 16.9%–33.3%; p<0.0001), and ARHs (35.8%; 95% CI: 19.6%–48.7%; p = 0.02). Moreover, AT was associated with significant reductions in most asthma prescription refills, including bronchodilators (16.7%; 95% CI: 16.1%–17.3%; p<0.001), inhaled corticosteroids (21.5%; 95% CI: 20.7%–22.3%; p<0.001), leukotriene receptor antagonists (13.4%; 95% CI: 12.9%–14.0%; p<0.001), and systemic corticosteroids (23.7%; 95% CI: 20.9%–26.5%; p<0.001). In contrast, there were no significant reductions in these outcomes in children with asthma who did not undergo AT over an overlapping follow-up period. Limitations of the MarketScan database include lack of information on race and obesity status. Also, the MarketScan database does not include information on children with public health insurance (i.e., Medicaid) or uninsured children.
In a very large sample of privately insured children, AT was associated with significant improvements in several asthma outcomes. Contingent on validation through prospectively designed clinical trials, this study supports the premise that detection and treatment of adenotonsillar tissue morbidity may serve as an important strategy for improving asthma control.
Please see later in the article for the Editors' Summary
Editors' Summary
The global burden of asthma has been rising steadily over the past few decades. Nowadays, about 200–300 million adults and children worldwide are affected by asthma, a chronic condition caused by inflammation of the airways (the tubes that carry air in and out of the lungs). Although asthma can develop at any age, it is often diagnosed in childhood—asthma is one of the commonest chronic diseases in children. In the US, for example, asthma affects around 7.1 million children under the age of 18 years and is the third leading cause of hospitalization of children under the age of 15 years. In people with asthma, the airways can react very strongly to allergens such as animal fur or to irritants such as cigarette smoke. Exercise, cold air, and infections can trigger asthma attacks, which can be fatal. The symptoms of asthma include wheezing, coughing, chest tightness, and shortness of breath. Asthma cannot be cured, but drugs can relieve its symptoms and prevent acute asthma attacks.
Why Was This Study Done?
Recent studies have found an association between severe childhood asthma and obstructive sleep apnea (OSA). In OSA, airway inflammation promotes hypertrophy (excess growth) of the adenoids and the tonsils, immune system tissues in the upper airway. During sleep, the presence of hypertrophic adenotonsillar tissues predisposes the walls of the throat to collapse, which results in apnea—a brief interruption in breathing. People with OSA often snore loudly and frequently wake from deep sleep as they struggle to breathe. Childhood OSA, which affects 2%–3% of children, can be effectively treated by removal of the adenoids and tonsils (adenotonsillectomy). Given the association between childhood OSA and severe asthma and given the involvement of airway inflammation in both conditions, might adenotonsillectomy also improve childhood asthma? Here, the researchers analyze data from the MarketScan database, a large database of US patients with private health insurance, to investigate whether adenotonsillectomy is associated with improvements in asthma outcomes and with reductions in the use of asthma therapies in children.
What Did the Researchers Do and Find?
The researchers used the database to identify 13,506 children with asthma who had undergone adenotonsillectomy and to obtain information about asthma outcomes among these children for the year before and the year after the operation. Because asthma severity tends to decrease with age, the researchers also used the database to identify 27,012 age-, sex-, and geographically matched children with asthma who did not have the operation so that they could examine asthma outcomes over an equivalent two-year period in the absence of complications related to adenotonsillar hypertrophy. Comparing the year after adenotonsillectomy with the year before the operation, adenotonsillectomy was associated with a 30% reduction in acute asthma exacerbations, a 37.9% reduction in acute status asthmaticus (an asthma attack that is unresponsive to the drugs usually used to treat attacks), a 25.6% reduction in asthma-related emergency room visits, and a 35.8% reduction in asthma-related hospitalizations. By contrast, among the control children, there was only a 2% reduction in acute asthma exacerbations and only a 7% reduction in acute status asthmaticus over an equivalent two-year period. Adenotonsillectomy was also associated with significant reductions (changes unlikely to have occurred by chance) in prescription refills for most types of drugs used to treat asthma, whereas there were no significant reductions in prescription refills among children with asthma who had not undergone adenotonsillectomy. The study was limited by the lack of measures of race and obesity, which are both associated with severity of asthma.
What Do These Findings Mean?
These findings show that in a large sample of privately insured children in the US, adenotonsillectomy was associated with significant improvements in several asthma outcomes. These results do not show, however, that adenotonsillectomy caused a reduction in the severity of childhood asthma. It could be that the children who underwent adenotonsillectomy (but not those who did not have the operation) shared another unknown factor that led to improvements in their asthma over time. To prove a causal link, it will be necessary to undertake a randomized controlled trial in which the outcomes of groups of children with asthma who are chosen at random to undergo or not undergo adenotonsillectomy are compared. However, with the proviso that there are some risks associated with adenotonsillectomy, these findings suggest that the detection and treatment of adenotonsillar hypertrophy may help to improve asthma control in children.
Additional Information
Please access these websites via the online version of this summary at
The US Centers for Disease Control and Prevention provides information on asthma, including videos, games, and links to other resources for children with asthma
The American Lung Association provides detailed information about asthma and a fact sheet on asthma in children; it also has information about obstructive sleep apnea
The National Sleep Foundation provides information on snoring and obstructive sleep apnea in children
The UK National Health Service Choices website provides information (including some personal stories) about asthma, about asthma in children, and about obstructive sleep apnea
The “Global Asthma Report 2014” will be available in October 2014
MedlinePlus provides links to further information on asthma, on asthma in children, on sleep apnea, and on tonsils and adenoids (in English and Spanish)
PMCID: PMC4219664  PMID: 25369282
16.  The Response of Children with Asthma to Ambient Particulate Is Modified by Tobacco Smoke Exposure 
Rationale: Ambient particulate matter concentrations have been positively associated with urinary leukotriene E4 (LTE4) levels and albuterol usage in children with asthma but interactions with environmental tobacco smoke (ETS) exposure have not been demonstrated despite obvious exposure to both pollutants in an urban setting.
Objectives: To assess the health effects of concurrent ETS and ambient particulate matter exposure in children with asthma.
Methods: Albuterol usage and LTE4 levels were monitored in 82 urban schoolchildren with asthma over three consecutive fall to spring school periods. Concentrations of morning maximum ambient particulate matter <2.5 μm in aerodynamic diameter (mmPM2.5) and urine cotinine levels were also measured daily.
Measurements and Main Results: Albuterol usage and LTE4 were related to mmPM2.5 concentrations on days when urine cotinine levels were low (<10 ng/ml/mg creatinine); on these days, mean albuterol usage and LTE4 increased up to 5 or 6% per 10 μg/m3 increase in mmPM2.5. In contrast, no significant relationship was observed when cotinine was high, although mean albuterol usage and LTE4 levels were greater in this case. Model fits for LTE4 levels as a function of mmPM2.5 concentrations were improved when mmPM2.5 concentrations were logged, suggesting a nonlinear dose–response relationship between particulate matter exposure concentrations and airway mediators of asthma, for which the relationship tends to flatten at higher concentrations.
Conclusions: This study suggests that ETS modifies the acute effects of low-level ambient PM2.5 exposure on childhood asthma. This negative interaction, the smaller effect of particulate matter exposure in children exposed to higher ETS, may be related to a nonlinear dose–response relationship between asthma mediators and particulate exposures.
PMCID: PMC3262032  PMID: 21868505
air pollution; leukotriene E4; asthma; interaction; environmental tobacco smoke
17.  Salivary cotinine concentration versus self-reported cigarette smoking: Three patterns of inconsistency in adolescence 
The present study examined the extent and sources of discrepancies between self-reported cigarette smoking and salivary cotinine concentration among adolescents. The data are from household interviews with a cohort of 1,024 adolescents from an urban school system. Histories of tobacco use in the last 7 days and saliva samples were obtained. Logistic regressions identified correlates of three inconsistent patterns: (a) Pattern 1—self-reported nonsmoking among adolescents with cotinine concentration above the 11.4 ng/mg cutpoint (n=176), (b) Pattern 2—low cotinine concentration (below cutpoint) among adolescents reporting having smoked within the last 3 days (n=155), and (c) Pattern 3—high cotinine concentration (above cutpoint) among adolescents reporting not having smoked within the last 3 days (n=869). Rates of inconsistency were high among smokers defined by cotinine levels or self-reports (Pattern 1=49.1%; Pattern 2=42.0%). Controlling for other covariates, we found that reports of nonsmoking among those with high cotinine (Pattern 1) were associated with younger age, having few friends smoking, little recent exposure to smokers, and being interviewed by the same interviewer as the parent and on the same day. Low cotinine concentration among self-reported smokers (Pattern 2) was negatively associated with older age, being African American, number of cigarettes smoked, depth of inhalation, and exposure to passive smoke but positively associated with less recent smoking and depressive symptoms. High cotinine concentrations among self-reported nonsmokers was positively associated with exposure to passive smoke (Pattern 3). The data are consonant with laboratory findings regarding ethnic differences in nicotine metabolism rate. The inverse relationship of cotinine concentration with depressive symptoms has not previously been reported. Depressed adolescent smokers may take in smaller doses of nicotine than nondepressed smokers; alternatively, depressed adolescents may metabolize nicotine more rapidly.
PMCID: PMC2538943  PMID: 16920650
18.  Particle Concentrations and Effectiveness of Free-Standing Air Filters in Bedrooms of Children with Asthma in Detroit, Michigan 
Building and environment  2011;46(11):2303-2313.
Asthma can be exacerbated by environmental factors including airborne particulate matter (PM) and environmental tobacco smoke (ETS). We report on a study designed to characterize PM levels and the effectiveness of filters on pollutant exposures of children with asthma. 126 households with an asthmatic child in Detroit, Michigan, were recruited and randomized into control or treatment groups. Both groups received asthma education; the latter also received a free-standing high efficiency air filter placed in the child’s bedroom. Information regarding the home, emission sources, and occupant activities was obtained using surveys administered to the child's caregiver and a household inspection. Over a one-week period, we measured PM, carbon dioxide (CO2), environmental tobacco smoke (ETS) tracers, and air exchange rates (AERs). Filters were installed at midweek. Before filter installation, PM concentrations averaged 28 µg m−3, number concentrations averaged 70,777 and 1,471 L−1 in 0.3–1.0 and 1–5 µm size ranges, respectively, and the median CO2 concentration was 1,018 ppm. ETS tracers were detected in 23 of 38 homes where smoking was unrestricted and occupants included smokers and, when detected, PM concentrations were elevated by an average of 15 µg m−3. Filter use reduced PM concentrations by an average of 69 to 80%. Simulation models representing location conditions show that filter air flow, room volume and AERs are the key parameters affecting PM removal, however, filters can achieve substantial removal in even "worst" case applications. While PM levels in homes with asthmatic children can be high, levels can be dramatically reduced using filters.
PMCID: PMC3161201  PMID: 21874085
indoor environment; free-standing HEPA air filters; asthmatic children; particulate matter; exposures
19.  Reduction in Asthma Morbidity in Children as a Result of Home Remediation Aimed at Moisture Sources 
Environmental Health Perspectives  2006;114(10):1574-1580.
Home dampness and the presence of mold and allergens have been associated with asthma morbidity. We examined changes in asthma morbidity in children as a result of home remediation aimed at moisture sources.
In this prospective, randomized controlled trial, symptomatic, asthmatic children (n = 62), 2–17 years of age, living in a home with indoor mold, received an asthma intervention including an action plan, education, and individualized problem solving. The remediation group also received household repairs, including reduction of water infiltration, removal of water-damaged building materials, and heating/ventilation/air-conditioning alterations. The control group received only home cleaning information. We measured children’s total and allergen-specific serum immuno-globulin E, peripheral blood eosinophil counts, and urinary cotinine. Environmental dust samples were analyzed for dust mite, cockroach, rodent urinary protein, endotoxin, and fungi. The follow-up period was 1 year.
Children in both groups showed improvement in asthma symptomatic days during the preremediation portion of the study. The remediation group had a significant decrease in symptom days (p = 0.003, as randomized; p = 0.004, intent to treat) after remodeling, whereas these parameters in the control group did not significantly change. In the postremediation period, the remediation group had a lower rate of exacerbations compared with control asthmatics (as treated: 1 of 29 vs. 11 of 33, respectively, p = 0. 003; intent to treat: 28.1% and 10.0%, respectively, p = 0.11).
Construction remediation aimed at the root cause of moisture sources and combined with a medical/behavioral intervention significantly reduces symptom days and health care use for asthmatic children who live in homes with a documented mold problem.
PMCID: PMC1626393  PMID: 17035145
asthma; children; damp housing; home remediation; indoor mold
20.  Characteristics of nonsmoking women exposed to spouses who smoke: epidemiologic study on environment and health in women from four Italian areas. 
Environmental Health Perspectives  2000;108(12):1171-1177.
The aim of this study was to evaluate whether risk factors associated with cardiovascular or respiratory diseases and lung cancer occur differently among nonsmoking women in Italy with and without exposure to environmental tobacco smoke (ETS) from husbands that smoke. We performed a cross-sectional study of 1,938 nonsmoking women in four areas of Italy. Data on respiratory and cardiovascular risk factors and on diet were collected using self-administered questionnaires. Medical examinations and blood tests were administered; urine cotinine levels were measured. Nonsmoking women ever exposed to husbands' smoking were compared with unexposed women for several factors: education, husband's education, household crowding, number of children, current or past occupation, exposure to toxic substances at work, parental diseases, self-perceived health status, physician-diagnosed hypertension, hypercholesterol, diabetes, osteoporosis, chronic respiratory diseases, blood pressure medications, lifestyle and preventive behaviors, dietary variables, systolic and diastolic blood pressure, body mass index, waist-hip ratio, triceps skin folds, plasma antioxidant (pro-) vitamins (- and ss-carotene, retinol, l-ascorbic acid, -tocopherol, lycopene), serum total and HDL cholesterol, and triglycerides. Women married to smokers were more likely to be less educated, to be married to a less educated husband, and to live in more crowded dwellings than women married to nonsmokers. Women married to smokers were significantly less likely to eat cooked [odds ratio (OR) = 0.72; 95% confidence interval (CI), 0.55-0.93] or fresh vegetables (OR = 0.63; CI, 0.49-0.82) more than once a day than women not exposed to ETS. Exposed women had significantly higher urinary cotinine than unexposed subjects (difference: 2.94 ng/mg creatinine). All the other variables were not more prevalent among exposed compared to unexposed subjects. The results regarding demographic factors are easily explained by the social class distribution of smoking in Italy. A lower intake of vegetables among exposed women in our study is consistent with the available literature. Overall, our results do not support previous claims of more frequent risk factors for cardiovascular and pulmonary diseases among ETS-exposed subjects. In Italy, as elsewhere in Europe and North America, women who have never smoked but are married to smokers are likely to be of lower social class than those married to never-smokers. However, once socioeconomic differences are considered, the possibility of confounding in studies on the health effects of ETS is minimal.
PMCID: PMC1240199  PMID: 11133398
21.  A survey of schoolchildren's exposure to secondhand smoke in Malaysia 
BMC Public Health  2011;11:634.
There is a lack of data describing the exposure of Malaysian schoolchildren to Secondhand Smoke (SHS). The aim of this study is to identify factors influencing schoolchildren's exposures to SHS in Malaysia.
This cross-sectional study was carried out to measure salivary cotinine concentrations among 1064 schoolchildren (10-11 years) attending 24 schools in Malaysia following recent partial smoke-free restrictions. Parents completed questionnaires and schoolchildren provided saliva samples for cotinine assay.
The geometric mean (GM) salivary cotinine concentrations for 947 non-smoking schoolchildren stratified by household residents' smoking behaviour were: for children living with non-smoking parents 0.32 ng/ml (95% CI 0.28-0.37) (n = 446); for children living with a smoker father 0.65 ng/ml (95% CI 0.57-0.72) (n = 432); for children living with two smoking parents 1.12 ng/ml (95% CI 0.29-4.40) (n = 3); for children who live with an extended family member who smokes 0.62 ng/ml (95% CI 0.42-0.89) (n = 33) and for children living with two smokers (father and extended family member) 0.71 ng/ml (95% CI 0.40-0.97) (n = 44). Parental-reported SHS exposures showed poor agreement with children's self-reported SHS exposures. Multiple linear regression demonstrated that cotinine levels were positively associated with living with one or more smokers, urban residence, occupation of father (Armed forces), parental-reported exposure to SHS and education of the father (Diploma/Technical certificate).
This is the first study to characterise exposures to SHS using salivary cotinine concentrations among schoolchildren in Malaysia and also the first study documenting SHS exposure using salivary cotinine as a biomarker in a South-East Asian population of schoolchildren. Compared to other populations of similarly aged schoolchildren, Malaysian children have higher salivary cotinine concentrations. The partial nature of smoke-free restrictions in Malaysia is likely to contribute to these findings. Enforcement of existing legislation to reduce exposure in public place settings and interventions to reduce exposure at home, especially to implement effective home smoking restriction practices are required.
PMCID: PMC3162528  PMID: 21824403
Secondhand smoke; salivary cotinine; schoolchildren; self-reported smoke exposure; smoke-free legislation; enzyme-immunoassay method
22.  Reducing Environmental Tobacco Smoke Exposure of Preschool Children: A Randomized Controlled Trial of Class-Based Health Education and Smoking Cessation Counseling for Caregivers 
Objectives: To assess counseling to caregivers and classroom health education interventions to reduce environmental tobacco smoke exposure of children aged 5–6 years in China. Methods: In a randomized controlled trial in two preschools in Changsha, China, 65 children aged 5–6 years old and their smoker caregivers (65) were randomly assigned to intervention (n = 33) and control (no intervention) groups (n = 32). In the intervention group, caregivers received self-help materials and smoking cessation counseling from a trained counselor, while their children were given classroom-based participatory health education. Children’s urinary cotinine level and the point prevalence of caregiver quitting were measured at baseline and after 6 months. Results: At the 6-month follow-up, children’s urinary cotinine was significantly lower (Z = –3.136; p = 0.002) and caregivers’ 7-day quit rate was significantly higher (34.4% versus 0%) (p < 0.001; adjusted OR = 1.13; 95% CI: 1.02–1.26) in the intervention than control group. Conclusions: Helping caregivers quitting smoke combined with classroom-based health education was effective in reducing children’s environmental tobacco smoke exposure. Larger-scale trials are warranted.
PMCID: PMC4306887  PMID: 25590146
environmental tobacco smoke (ETS); young children; intervention; urinary cotinine
23.  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; χ2=142.14, and χ2=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 (r2=0.55) than urine cotinine (r2=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.
PMCID: PMC1732006  PMID: 11801622
24.  Relationship between Caregivers’ Smoking at Home and Urinary Levels of Cotinine in Children 
Objective: To assess the impact of different smoking behaviors of caregivers on environmental tobacco smoke (ETS) exposure in children aged 5–6 years in Changsha, China. Methods: We conducted a cross-sectional, random digit-dial telephone survey of caregivers (n = 543) between August and October 2013. Caregivers’ smoking behaviors were collected by a questionnaire. Exposure assessment was based upon determination of urinary cotinine levels in children employing gas chromatography–triple quadrupole mass spectrometry (GC-MS/MS). Results: In children not living with a smoker, children living with one smoker, and children living with more than one smoker at home, median urinary cotinine concentrations (ng/mL) were 0.72, 2.97, and 4.46, respectively. For children living with one smoker, median urinary cotinine levels of children exposed to ETS were associated with caregiver smoking behaviors, i.e., if a caregiver consumed more cigarettes (>20 compared with ≤10; 7.73 versus 2.29 ng/mL, respectively). Conclusions: The magnitude of ETS exposure in children is correlated with the smoking behaviors of the caregiver. Counseling for smoking cessation and educational interventions are needed urgently for smoking caregivers to increase their awareness about ETS exposure and to encourage smoking cessation at home or to take precautions to protect children’s health.
PMCID: PMC4276627  PMID: 25469922
smoking; caregiver; environmental tobacco smoke (ETS); children; gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS); cotinine
25.  The association between endotoxin and lung function among children and adolescents living in a rural area 
Increased levels of endotoxin found in rural and agricultural areas are an environmental exposure believed to cause a paradoxical proinflammatory effect on respiratory health that can exacerbate asthma. Previous studies involving adults have demonstrated an association between high endotoxin levels and lower lung function. Apart from occupational settings, however, few studies have investigated the relationship between lung function and endotoxin exposure, such as environmental tobacco smoke, especially in children. This study examined the modifying effects of sex, pre-existing asthma and other environmental exposures, including tobacco smoke, in children living in rural communities in Saskatchewan.
Knowledge of the effects of domestic endotoxin on children’s lung function is limited. The association between domestic endotoxin and asthma or wheeze and lung function among school-age children (six to 18 years of age) was examined. The interaction between endotoxin and other personal and environmental characteristics and lung function was also assessed.
A case-control study was conducted in and around the rural community of Humboldt, Saskatchewan, between 2005 and 2007. Parents of cases reported either doctor-diagnosed asthma or wheeze in the previous year. Controls were randomly selected from those not reporting these conditions. Data were collected by questionnaire to ascertain symptoms and conditions, while spirometry was used to measure lung function including forced vital capacity and forced expiratory volume in 1 s. Dust collected from the child’s play area floor and the child’s mattress was used to quantify endotoxin, and saliva was collected to quantify cotinine levels and assess tobacco smoke exposure.
There were 102 cases and 207 controls included in the present study. Lower forced expiratory volume in 1 s was associated with higher mattress endotoxin load among female cases (beta=−0.25, SE=0.07 [P<0.01]). There was a trend toward lower forced vital capacity, which was associated with higher play area endotoxin load among cases with high tobacco smoke exposure (beta=−0.17, SE=0.09 [P<0.10]).
Findings indicated that high endotoxin levels present in common household areas of rural children with asthma or wheeze may also affect their lung function. These associations may be potentiated by tobacco smoke exposure and female sex.
PMCID: PMC3267627  PMID: 22187693
Asthma; Endotoxin; Lung function; Rural; Tobacco smoke; Wheeze

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