Socioeconomic inequalities in exposure to environmental tobacco smoke in children in Israel

Association between parental smoking and child exposure to environmental tobacco smoke in Israel

BACKGROUND

Environmental tobacco smoke (ETS) exposure in children can cause delayed lung development and lifelong cardiovascular damage. The aim of this study was to measure ETS exposure in children in Israel in 2020-2021 using urinary cotinine (UC) measurements and to assess correlates of ETS exposure, including parental smoking.

METHODS

In the framework of the National Human Biomonitoring Program, spot urine samples and questionnaire data were collected from 166 children aged 4-12 years, during the years 2020-2021. We collected urine samples in 233 adults, 69 of whom were parents of children included in the study. Parents of participating children were asked about parental smoking, child's exposure to ETS and smoking policy at home. Cotinine and creatinine were measured in urine. Creatinine-adjusted and unadjusted urine cotinine (UC) geometric means were calculated. Associations between potential correlates and UC concentrations were analyzed in univariate and multivariate analyses. For 69 child-parent pairs, correlation between child and parental UC was analyzed.

RESULTS

Based on urinary cotinine measurement, 65.2% of children of smokers are exposed to ETS, compared to 20.7% of children in non-smoking families. Greater numbers of smokers living in the home (beta = 1.27, p < 0.01), and low maternal education (beta = - 2.32, p < 0.01) were associated with higher levels of UC in a multivariate analysis. Spearman correlations showed a positive moderate correlation between UC in 69 child-parent pairs (r = 0.52, p < 0.01).

CONCLUSIONS

In order to reduce child exposure to ETS, smoking parents should be urgently targeted for smoking cessation and smoke-free home interventions. Further interventions are needed to protect all children from ETS.

Methods in Public Health Environmental Justice Research: a Scoping Review from 2018 to 2021

PURPOSE OF REVIEW

The volume of public health environmental justice (EJ) research produced by academic institutions increased through 2022. However, the methods used for evaluating EJ in exposure science and epidemiologic studies have not been catalogued. Here, we completed a scoping review of EJ studies published in 19 environmental science and epidemiologic journals from 2018 to 2021 to summarize research types, frameworks, and methods.

RECENT FINDINGS

We identified 402 articles that included populations with health disparities as a part of EJ research question and met other inclusion criteria. Most studies (60%) evaluated EJ questions related to socioeconomic status (SES) or race/ethnicity. EJ studies took place in 69 countries, led by the US (n = 246 [61%]). Only 50% of studies explicitly described a theoretical EJ framework in the background, methods, or discussion and just 10% explicitly stated a framework in all three sections. Among exposure studies, the most common area-level exposure was air pollution (40%), whereas chemicals predominated personal exposure studies (35%). Overall, the most common method used for exposure-only EJ analyses was main effect regression modeling (50%); for epidemiologic studies the most common method was effect modification (58%), where an analysis evaluated a health disparity variable as an effect modifier. Based on the results of this scoping review, current methods in public health EJ studies could be bolstered by integrating expertise from other fields (e.g., sociology), conducting community-based participatory research and intervention studies, and using more rigorous, theory-based, and solution-oriented statistical research methods.

Tobacco smoke incursion into private residences in Israel: a cross-sectional study examining public perceptions of private rights and support for governmental policies

BACKGROUND

Tobacco smoke incursion (TSI) into private residences is a widespread problem in many countries. We sought to assess the prevalence of self-reported TSI and public attitudes about TSI in Israel, a country with a relatively high smoking prevalence and high population density.

METHODS

We conducted a random digit dial survey among residents in Israel (N = 285) in 2017, which examined the frequency, source, correlates of, and attitudes towards TSI and potential regulatory options. The cooperation rate was 63.9%.

RESULTS

Among respondents, 44.7% reported ever experiencing home TSI, with higher exposure among residents of multi-unit housing (MUH) (MUH versus private homes: aOR (Adjusted Odds Ratio): 3.60, CI (Confidence Interval): [1.96, 6.58], p < .001). Most respondents (69.8%), including nearly half of smokers, prioritized the right of individuals to breath smoke-free air in their apartments over the right of smokers to smoke in their apartments. Women and non-smokers were more likely to support the right to breathe smoke-free air (Women versus men: aOR: 2.77 CI: [1.48, 5.16], p = .001; Nonsmokers versus smokers: aOR: 3.21 CI [1.59, 6.48], p = .001). However, only about a quarter (24.8%) of respondents who ever experienced TSI raised the issue with the neighbor who smoked, the neighbor's landlord, or the building committee. The vast majority (85.2%) of all respondents, including three-quarters of smokers, supported smoke-free legislation for multi-unit housing (MUH), with those ever-exposed to TSI and non-smokers more likely to support legislation (ever-exposed versus never-exposed aOR = 2.99, CI [1.28, 6.97], p = 0.011; nonsmokers versus smokers aOR = 3.00, CI [1.28, 7.01], p = 0.011).

CONCLUSIONS

Among study participants, tobacco smoke incursion was a common, yet unwelcome experience. Most respondents believed that the right to breathe smoke-free air in one's apartment superseded that of neighbors to smoke anywhere in their home, and most supported legislation to prevent TSI. Though further study is needed to understand better TSI and effective methods for its prevention, our findings suggest that policy interventions, including legal action at the level of the Supreme Court and/or the Knesset, are needed. Regulation, policy initiatives and campaigns to denormalize smoking in proximity to other people and private residences globally could reduce the scope of this widespread problem, protect individuals from home TSI, and improve population health.

The association between risk perceptions, anxiety, and self-reported changes in tobacco and nicotine product use due to COVID-19 in May-June 2020 in Israel

BACKGROUND

Early in the COVID-19 pandemic, reports about a possible protective effect of nicotine on COVID-19 conflicted with messaging by public health organizations about increased risks of COVID-19 due to smoking. The ambiguous information the public received, combined with COVID-19-induced anxiety, may have led to changes in tobacco or other nicotine product use. This study examined changes in use of combustible cigarettes (CCs), nargila (hookah/waterpipe), e-cigarettes, and IQOS and home-smoking behaviors. We also assessed COVID-19 related anxiety and perceptions regarding changes in risk of COVID-19 severity due to smoking.

METHODS

We used cross-sectional data from a population telephone survey that was conducted in Israel in the early phase of the COVID-19 pandemic (May-June 2020) and included 420 adult (age 18+) individuals who reported having ever used CCs (n = 391), nargila (n = 193), and/or electronic cigarettes (e-cigarettes)/heated tobacco products (e.g., IQOS) (n = 52). Respondents were asked about the effect that COVID-19 had on their nicotine product use (quit/reduced use, no change, increased use). We assessed changes in product use, risk perceptions, and anxiety using adjusted multinomial logistic regression analyses.

RESULTS

Most respondents did not change their frequency of product use (CCs: 81.0%, nargila: 88.2%, e-cigarettes/IQOS: 96.8%). A small percentage either decreased use (CCs: 7.2%, nargila: 3.2%, e-cigarettes/IQOS:2.4%) or increased use (CCs:11.8%, nargila:8.6%, e-cigarettes/IQOS:+ 0.9%). 55.6% of respondents used a product in the home prior to COVID-19; but during the first lockdown COVID-19 period, a greater percentage increased (12.6%) than decreased (4.0%) their home use. Higher levels of anxiety due to COVID-19 were associated with increased home smoking (aOR = 1.59, 95% CI:1.04-2.42, p = 0.02). Many respondents believed that increased severity of COVID-19 illness was associated with CCs (62.0%) and e-cigarettes/vaping (45.3%), with uncertainty about the association being lower for CCs (20.5%) than for vaping (41.3%).

CONCLUSIONS

While many respondents believed that nicotine product use (particularly CCs and e-cigarettes) was associated with increased risk of COVID-19 disease severity, the majority of users did not change their tobacco/nicotine use. The confusion about the relationship between tobacco use and COVID-19 calls for clear evidence-based messaging from governments. The association between home smoking and increased COVID-19-related stress suggests the need for campaigns and resources to prevent smoking in the home, particularly during times of stress.

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

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

Association between Environmental Tobacco Smoke Exposure and Adaptive Behavior in Individuals with Autism Spectrum Disorder

The study focuses on current issues of adaptive behavior in individuals with autism spectrum disorder (ASD) and on the possible risk factor of environmental tobacco smoke (ETS). Children examined at the Academic Research Center for Autism (ARCA) in Bratislava were involved in the study. The study sample included 84 children (71 boys) with ASD (average age 5.35 years) and a non-ASD group of 24 children (20 boys; average age 8.10 years). The “ETS Questionnaire” focused on the detection of parental smoking habits and other ETS exposures. The concentrations of cotinine in urine were measured by ELISA kit. A significant delay in adaptive behavior of children with ASD in comparison with the non-ASD group was identified. The significant differences were in adaptive behavior, communication, and everyday skills. Children with ASD were more likely to be exposed to ETS, especially in the household. Good agreement was found between objective and subjective ETS exposure indicators (kappa = 0.613). Self-reported exposure to ETS corresponded significantly with the median levels of urinary cotinine. In addition to evaluation and assessment of the quality of adaptive behavior, an important goal of further research should be to identify, investigate, and eliminate environmental factors that interfere with adaptive behavior.

Protecting Children From Tobacco Smoke Exposure: A Randomized Controlled Trial of Project Zero Exposure

INTRODUCTION

Young children are vulnerable to harm from tobacco smoke exposure (TSE). This study assessed the effect of Project Zero Exposure-an intervention program designed to help parents protect children from TSE-on children's exposure.

METHODS

Randomized controlled trial of a home-based, theory-driven intervention. Parents of young children (<8 y) in families with a smoking parent were eligible. The intervention included feedback on child TSE (hair nicotine), and home air quality (PM2.5), with motivational interviewing. Families were randomized to: intervention group (IG, N = 69), regular control group (RCG, N = 70), or to a secondary enhanced control group, (ECG, N = 20). Child hair samples were taken at baseline and follow-up. We report on child TSE in the IG versus RCG at six months.

RESULTS

Most enrolled families completed the trial (IG: 98.6%[68/69], RCG: 97.1%[68/70]). Log hair nicotine (LHN [ng/mg]) decreased in both the IG (Baseline: -1.78 ± 1.91, Follow-up: -2.82 ± 1.87, p = .003) and RCG (Baseline: -1.79 ± 1.54, Follow-up: -2.85 ± 1.73, p = .002), but did not differ between groups at study end (p = .635). Three of five parentally-reported outcomes showed improvement over time in the IG, and one in the RCG. Among IG participants, 90% found hair nicotine feedback useful.

CONCLUSIONS

No difference between the intervention and control groups was found on the objective biomarker, LHN. Child TSE decreased during the trial in intervention and control groups. Trial participation, which included hair nicotine monitoring, may have contributed to decreasing exposure in both groups. Concurrent control group improvements may partially explain lack of proven intervention benefit. Biomarker monitoring warrants further investigation for reduction of child TSE.

IMPLICATIONS

Project Zero Exposure is an intervention program designed to help parents protect their children from TSE. Results from the randomized controlled trial of the program showed no difference between groups at study end, but a clear and substantial reduction in child exposure to tobacco smoke from beginning to end of the trial, in both intervention and control groups. Biomarker monitoring, a key element of the trial, was used with all participants. Biomarker monitoring of child exposure to tobacco smoke may help parents become aware of their child's exposure and better protect them, and should be explored as a means to reduce child TSE. Clinical Trial Registration: NCT02867241.

Exposure to Secondhand Smoke: Inconsistency between Self-Response and Urine Cotinine Biomarker Based on Korean National Data during 2009-2018

This study aimed to estimate the secondhand smoke (SHS) exposure using urinary cotinine (UCo) to prove that the SHS exposure could not be properly assessed by self-reporting (SR). In total, 28,574 nonsmokers aged >19 years were selected from the Korean National Health and Nutrition Examination Survey data (2009-2018). First, changes in the annual concentration of UCo were analyzed, and the annual SHS exposure rates were measured based on SR and UCo from 2009 to 2018. Then, the average UCo concentration and UCo-measured SHS exposure rate were confirmed according to the subjects' characteristics. Finally, factors associated with the UCo-measured SHS exposure rate were identified based on multiple regression analysis. The findings showed that the annual UCo concentrations and self-reported SHS exposure rates dropped significantly over the past decade. In contrast, the UCo-measured SHS exposure rate indicated that >80% of nonsmokers are still exposed to SHS. Moreover, we found vulnerable groups using UCo-measured SHS exposure rate. In particular, the self-reported SHS exposure at home and in workplaces and house type was highly associated with SHS exposure. Thus, these findings indicate that the actual SHS exposure could not be properly assessed by SR and should be verified using a biomarker, such as UCo. Considering that even a short-term exposure can be harmful to health, the goal of the policy should be to keep cotinine concentration as low as possible.

Association between Parental Cotinine-verified Smoking Status and Childhood Asthma: a Population-based Nationally Representative Analysis

BACKGROUND

Environmental tobacco smoke exposure due to parents is a modifiable risk factor for childhood asthma, but many studies have evaluated parental smoking using self-reported data. Therefore, we aimed to analyze the relationship between parental cotinine-verified smoking status and asthma in their children.

METHODS

This population-based cross-sectional study used data from the Korean National Health and Nutrition Examination Survey from 2014 to 2017. Participants aged 0 to 18 years with complete self-reported physician-diagnosed childhood asthma and measurement of their parental urinary cotinine levels were included. Parental urinary cotinine-verified smoking status was defined using both urinary cotinine levels and self-report, as active, passive, and non-smoker. Sample weights were applied to all statistical analyses because of a complex, multistage and clustered survey design. Logistic regression model was used to analyze the relationship between childhood asthma and parental smoking.

RESULTS

A total of 5,264 subjects aged < 19 years were included. The prevalence of asthma was 3.4%. The proportions of paternal and maternal urinary cotinine-verified active smokers during the study period were 50.4% and 16.9%, respectively. When parental urinary cotinine level increased, the proportion of parental low household income was increased (P < 0.001). There was no significant association between the parental urinary cotinine-verified smoking group and childhood asthma group. However, the adjusted odds ratios of childhood asthma in the middle and highest tertile of paternal urinary cotinine levels compared with those in lowest tertile were 1.95 (95% confidence interval [CI], 0.98-3.89) and 2.34 (95% CI, 1.21-4.54), respectively.

CONCLUSION

There seems to be a dose-related association between paternal urinary cotinine levels and the risk of childhood asthma. Because of the high rate of paternal smoking, further studies are needed to develop a targeted strategy to reduce parental smoking for childhood asthma.

Environmental Tobacco Smoke Exposure Among Children by Urinary Biomarkers and Parent Report

OBJECTIVE

The goal of this study was to describe environmental tobacco smoke (ETS) exposure using urinary biomarkers and its correlation with parent report, among children presenting to emergency room.

METHODS

This is a case control study among children aged 3 to 12 years at a tertiary pediatric emergency department in Israel. Children with respiratory (case) or gastrointestinal (control) symptoms were recruited and their accompanying parent completed a short survey. Urine samples were obtained and analyzed for nicotine, cotinine trans-3'-hydroxycotine. Clinical data were extracted from medical records. We compared tobacco exposure using urinary biomarkers, parent report, and Pearson's product-moment correlation, including 95% confidence intervals, between cases and controls.

RESULTS

Forty-nine cases with respiratory symptoms and 96 controls with gastrointestinal symptoms were enrolled in the study. Parent-reported ETS exposure in the previous month was higher in the cases compared to control (71.4% vs 57.3%), although the difference was not statistically significant. The mean values of detectable biomarkers did not differ by between cases and controls. However, there was a correlation between urinary biomarkers and reported ETS exposure (0.278-0.460 for various biomarkers) only among cases.

CONCLUSIONS

The majority of children in this study had detectable nicotine urinary biomarkers, regardless of their symptoms. However, correlation between parental report and urinary biomarkers was only found among children with symptoms potentially related to ETS. These findings imply that parents of children without respiratory symptoms may underestimate exposure. Efforts to educate parents and caregivers on the risks associated with exposure to ETS should be intensified, regardless of illness.

Respiratory Symptoms and Urinary Cotinine Levels in Pre-school Children Exposed to Environmental Tobacco Smoke

Objective: Preschool children exposed to environmental tobacco smoke (ETS) are at risk of developing adverse respiratory health effects. The present study aimed to investigate the relationship between the effects of cigarette-smoking caregivers on respiratory symptoms and urinary cotinine (UC) levels in children. Methods: A cross-sectional study consisting of 543 children (aged between 5 and 6 years) from 5 kindergartens in central China was conducted using a structured questionnaire. We also analyzed UC levels to investigate the relationship between respiratory symptoms and ETS exposure. We further performed logistic regression analyses to establish the relationship between respiratory symptoms (coughing, rhinorrhea, and sneezing) and UC levels. Results: A total of 71 (13.08%) children had a history of hospital admission with respiratory illnesses including bronchitis and pneumonia over the last 6 months. In addition, 102 (18.78%) children presented coughing symptoms, 114 (20.99%) experienced rhinorrhea and 79 (14.55%) presented sneezing symptoms over the last 6 months. After adjusting the confounders, odds ratio (OR) indicated that the number of cigarettes smoked by a caregiver was associated with coughing (OR = 11.02; 95% CI, 3.72-33.66), rhinorrhea (OR = 41.83; 95% CI, 5.58-313.05) and sneezing (OR = 4.71; 95% CI, 1.33-16.48). Furthermore, UC levels in children with coughing, rhinorrhea and sneezing were significantly higher than in children without respiratory symptoms (P = 0.002, P < 0.001, P < 0.001, respectively). Conclusions: This study reveals that children exposed to ETS have higher levels of UC. Compared with caregiver who non-smoked live with children, smoked cigarettes were highly risk of developing respiratory illnesses in children. Notably, the higher the UC levels the greater the respiratory risk. Our results also signify that UC can be used as an indicator of ETS exposure to inform caregivers of the associated risks, and inform efforts to reduce related effects.

"I can't stand it…but I do it sometimes" parental smoking around children: practices, beliefs, and conflicts - a qualitative study

BACKGROUND

Many parents continue to smoke around their children despite the widely known risks of children's exposure to tobacco smoke. We sought to learn about parental smoking behavior around children from parents' perspective.

METHODS

Semi-structured interviews were conducted with 65 smoking parents or partners of smoking parents of children up to age 7, to learn about home smoking rules, behaviours performed to try to protect children, and smoking-related conflicts, from parents' perspective. Interviews were recorded and transcribed and thematic analysis performed. Recruitment was challenging due to the sensitive nature of the topic.

RESULTS

Many parents described smoking around their children in certain areas of the home, outdoors, and in what they consider to be open or ventilated areas. Participants emphasized efforts to protect their children and described various mitigating practices but held mixed views as to their effectiveness. Parents had different conceptions of which areas or distances were considered 'safe'. Many smoking parents described conflicts both internal and with other family members regarding the protection of children. Some parents who continue to smoke around their children despite understanding the health risks felt powerless to effect change, as well as being uncertain as to the effectiveness of their protective strategies; others were aware but reluctant to change.

CONCLUSION

Findings shed light on some of the difficulties faced by smoking parents and obstacles to maintaining a smoke-free environment for their children, providing insight for the type of information and support required to help parents better protect their children from exposure to tobacco smoke. Awareness of health risks associated with secondhand smoke was demonstrated, yet parents in smoking families were confused regarding which rules and behaviours best protect children from exposure to tobacco smoke. Parents were sometimes aware that their smoking 'rules' and mitigating practices were limited in their effectiveness. Guidelines should be provided explaining how and when exposure occurs and how to keep children safe.

Exposure to household secondhand smoke among adolescents in Kuwait: Results from two school-based cross-sectional studies

INTRODUCTION

Detrimental effects of secondhand smoke (SHS) exposure are well established; however, data on SHS exposure among adolescents in Kuwait are lacking. Hence, this study sought to estimate the prevalence of household SHS exposure among two samples of adolescents in Kuwait and assess its variation by socioeconomic status and parental education level.

METHODS

Data from two large school-based cross-sectional studies were analyzed. Adolescents attending public middle (n=3864; aged 11–14 years) and high (n=1959; aged 14–19 years) schools throughout Kuwait were enrolled in 2016-2017, and parental self-reported household SHS exposure was ascertained. Associations were assessed using Poisson regression with robust variance estimation, and adjusted prevalence ratios (APRs) and 95% confidence intervals (CIs) were estimated.

RESULTS

Overall, 45.8% (1755/3836; 95% CI: 44.2–47.3%) of the enrolled middle school students and 51.6% (998/1936; 95% CI: 49.3–53.8%) of the enrolled high school students were exposed to household SHS. Among middle and high school students, the prevalence of household SHS exposure increased as maternal/paternal education level and family income decreased. Among middle school students, paternal educational attainment of middle school or less compared to bachelor’s degree or higher was associated with 1.60 times (95% CI: 1.44–1.79) higher household SHS exposure. Similarly, in the sample of middle school students, the prevalence of household SHS exposure significantly increased from 35.8% among children from families reporting the highest household income to 50.5% among children from families with the lowest reported household income (p-trend<0.001).

CONCLUSIONS

Household SHS exposure is substantially high among adolescents in Kuwait. Enrolled adolescents from families with low socioeconomic status or with low parental education level have the highest household SHS exposure. These findings highlight the need for national comprehensive tobacco control policies and increasing parental awareness of the impact of SHS exposure on children.

Further Insights on Predictors of Environmental Tobacco Smoke Exposure during the Pediatric Age

Background: The smoking ban in public places has reduced Environmental Tobacco Smoke (ETS) exposure for non-smokers, but despite this, domestic environments still remain places at high risk of exposure, and, today, about 40% of children worldwide are exposed to ETS at home. The aims of the study are to investigate the contribution of several factors on ETS exposure among a group of Italian children and to evaluate the changes in smoking precautions adopted at home when the smoker is the mother, the father, or both parents, respectively. Methods: A cross-sectional study was performed on a sample of 519 Italian schoolchildren. Information was collected via a questionnaire. Results: 41.4% of the participants lived with at least one smoker. Almost half of the children exposed to ETS lived with one or more smokers who do not observe any home smoking ban. Lower maternal or paternal educational levels significantly increase the risk of ETS exposure at home and the "worst case" is represented by both parents who smoke. Conclusions: More effective preventive interventions are needed to protect children from ETS exposure. Some interventions should be specifically dedicated to smokers with a low educational level and to mothers that smoke.

Newborn infant urinary cotinine and birth outcomes in the Jerusalem Environment Mother and Child Cohort Study

BACKGROUND

Environmental tobacco smoke (ETS) exposure during pregnancy can cause preterm delivery and childhood cancer. The aim of this study was to measure ETS exposure in pregnant women and in newborn infants in Israel using urinary cotinine measurements, to assess predictors of ETS exposure in these vulnerable groups, and to assess associations with birth effects (birth weight, birth length, head circumference) in newborn infants.

METHODS

We analyzed urinary cotinine and creatinine in 265 non-smoking pregnant women and 97 newborns, and analyzed associations with self-reported exposure to ETS, paternal smoking, sociodemographic variables and with birth outcomes (birth weight, birth length, head circumference).

RESULTS

37.7% of pregnant women and 29.0% of infants had urinary cotinine concentrations above the level of quantification (LOQ) of 1 μg/L, whereas 63.8% and 50.5%, respectively, had urinary cotinine concentrations above the level of detection (LOD) of 0.5 μg/L. Median unadjusted and creatinine adjusted urinary concentrations of cotinine in pregnant women were 0.7 μg/L, and 0.9 μg/g creatinine, respectively, and in newborn infants were 0.5 μg/L, and 1.3 μg/g creatinine, respectively. We did not find an association between maternal and infant urinary cotinine level. Maternal (but not infant) urinary cotinine was significantly associated with paternal smoking (p < 0.05). Infant (but not maternal) cotinine above the LOQ was negatively associated with birth weight (p < 0.05).

CONCLUSIONS

In this high socioeconomic cohort, almost a third of newborn infants born to non-smoking mothers had quantifiable levels of urinary cotinine. This is the first study showing that newborns with quantifiable urinary cotinine levels have lower birth weight.