Biological matrices for the evaluation of exposure to environmental tobacco smoke during prenatal life and childhood

Tobacco Smoke Exposure in Pregnant Dogs: Maternal and Newborn Cotinine Levels: A Pilot Study

Active and passive smoking in pregnant women is associated with perinatal morbidity and mortality risk, including abortion, preterm birth, low birthweight, and malformations. No data are available on intrauterine exposure to smoking during pregnancy in dogs. This study aimed to fill this gap by exploring the detectability and quantity of cotinine, the major metabolite of nicotine, in maternal (serum and hair) and newborn (amniotic fluid and hair) biospecimens collected at birth in dogs. For this purpose, twelve pregnant bitches, six exposed to the owner's smoke and six unexposed, were enrolled. A further six non-pregnant bitches exposed to passive smoke were included to investigate the role of pregnancy status on cotinine uptake. Exposed dogs, dams, and puppies had greater cotinine concentrations than unexposed ones. Although without statistical significance, serum and hair cotinine concentrations were higher in pregnant compared to non-pregnant bitches, suggesting a different sensitivity to tobacco smoke exposure during gestation. The present results provide evidence for cotinine transplacental passage in the dog. It is conceivable that fragile patients such as pregnant, lactating, and neonate dogs may be more susceptible to the harmful effects of second-hand smoke exposure. Owners should be sensitized to the risk of smoke exposure for their pets.

BIOMARKERS OF MATERNAL SMOKING AND THE RISK OF RETINOBLASTOMA IN OFFSPRING

PURPOSE

Previous studies examining the risk of retinoblastoma with maternal smoking were inconclusive, likely due in part to the reliance on self-reported maternal smoking. This study uses biomarkers of tobacco smoking in neonatal dried blood spots to investigate associations between maternal smoking and retinoblastoma in offspring.

METHODS

The authors randomly selected 498 retinoblastoma cases and 895 control subjects born between 1983 and 2011 from a population-based case-control study in California. Maternal pregnancy-related smoking was measured using the following three metrics: provider or self-reported smoking during pregnancy, cotinine, and hydroxycotinine in neonatal blood. The authors used multivariable logistic regression to estimate the effects of maternal tobacco smoking on retinoblastoma.

RESULTS

Using all metrics (biomarkers or self-report), maternal smoking late in pregnancy or early postpartum was related to retinoblastoma (all types; odds ratio = 1.44, 95% confidence interval: 1.00-2.09). Relying on cotinine or hydroxycotinine to ascertain smoking, maternal smoking was related to unilateral retinoblastoma (odds ratio = 1.66, 95% confidence interval: 1.08-2.57).

CONCLUSION

The results indicate that maternal smoking during pregnancy may be a risk factor for retinoblastoma, particularly among unilateral cases.

Passive exposure to electronic cigarette aerosol in pregnancy: A case study of a family

BACKGROUND

Passive exposure to the aerosols of electronic cigarettes (e-cigarettes) has been little studied. We assessed this exposure in late pregnancy in a woman and her 3-year-old child, exposed through e-cigarette use by another household member.

METHODS

This prospective longitudinal case study involved a family unit consisting of an e-cigarette user, a pregnant woman who delivered an infant during the study, and the couple's older 3-year-old son. At 31, 36, and 40 weeks of the pregnancy, we measured biomarkers (nicotine metabolites, tobacco-specific nitrosamines, propanediols, glycerol, and metals) in the urine and hair of all three participants and in the saliva of the adults, in cord blood at delivery, and in the breast milk at the postpartum period.

RESULTS

Samples from the e-cigarette user showed quantifiable concentrations of all analytes assessed (maximum urinary cotinine concentration, 4.9 ng/mL). Among samples taken from the mother, nicotine and its metabolites were found mainly in urine and also in saliva and hair, but not in cord blood. During the postpartum period, we found cotinine concentrations of 2.2 ng/mL in the mother's urine and 0.22 ng/mL in breast milk; 1,2-propanediol was generally detected in urine and saliva, but not in cord blood or breast milk. The maximum urinary cotinine concentration in the 3-year-old child was 2.6 ng/mL and propanediols also were detected in his urine. Nitrosamines were not detected in samples taken from the mother or the 3-year-old. Metals found in the refill liquid were detected at low levels in both the mother and the 3-year-old.

CONCLUSIONS

We detected low but not negligible concentrations of e-cigarette-related analytes (including cord blood and breast milk) in an exposed pregnant non-user and in a 3-year-old child also living in the home. Passive exposure to e-cigarette aerosols cannot be disregarded and should be assessed in larger observational studies.

Pre- and postnatal maternal smoking and offspring smoking trajectories: Evidence from a 20-year birth cohort

Maternal smoking is associated with increased risk of smoking in the offspring. However, it remains unclear whether this association depends on the timing of exposure to maternal smoking. We investigated the association between prenatal and/or postnatal maternal smoking and offspring smoking during adolescence. Participants (N = 1661) were from the Québec Longitudinal Study of Child Development cohort. We identified longitudinal trajectories of maternal smoking from before pregnancy to child age 12 years using group-based trajectory modeling (GBTM). Adolescent (12-19 years) smoking trajectories were also identified using GBTM. Associations between maternal smoking and offspring smoking trajectories were estimated using multinomial logistic regressions. We used propensity score inverse probability weighting (IPW) to account for the differential distribution of maternal and familial characteristics across exposure groups. We identified four distinct groups for maternal smoking: no (66.1%), decreasing (5.6%), increasing (9.5%) and persistent (18.8%) smoking, and three adolescent smoking trajectories: abstinent, early-onset (before age 15) and late-onset (after age 15). In IPW-adjusted models, youth with mothers with decreasing, increasing and persistent smoking had higher risk of being early-onset smokers compared with youth with mothers in the non-smoking group. We also found that only youth whose mothers were persistent smokers had an increased risk of late-onset smoking. Regardless of timing, offspring exposure to maternal smoking is associated with increased risk of smoking during adolescence. More research is needed on how to create effective smoking cessation campaigns that span preconception, prenatal, and postnatal periods to help prevent intergenerational transmission of smoking behaviors.

Challenges associated with quantification of selected urinary biomarkers of exposure to tobacco products

Tobacco use, of which cigarette smoking is the most common, is a global health concern and is directly linked to over 7 million premature deaths annually. Measurement of the levels of tobacco-related biomarkers in biological matrices reflects human exposure to the chemicals in tobacco products. Nicotine, nicotine metabolites, anatabine, and anabasine are specific to tobacco and nicotine containing products. However, as nicotine and its metabolites are ubiquitous in the environment, background contamination during sample preparation can occur, making the quantification of target analytes challenging. The main purpose of the present study was to examine quality control measures needed in the determination of urinary nicotine, nicotine metabolites, anatabine, and anabasine. Urine samples (n = 75) and NIST standard reference materials SRM 3671 and SRM 3672 were analysed. A one-step extraction procedure using cold acetone was used in this study, which involved no additional clean up. The blank matrices investigated included synthetic urine prepared with HPLC-grade water, synthetic urine prepared with Milli-Q water, and bovine urine. By adopting strategies for minimizing the background levels, very low detection limits for all the target analytes ranging from 0.025 ng/mL for 3-hydroxycotinine to 0.634 ng/mL for nicotine, were achieved. Recoveries ranged between 67% and 118% with RSD values below 20%. Intra-day and inter-day precisions were in the range of 1.1-11.7% and 4.8-25.2%, respectively. The levels of all target analytes were higher in daily smokers than in non-smokers, with the largest difference observed for 3-hydroxycotinine. No difference was observed in the levels of target analytes between individuals who were former smokers, who never smoked or who were exposed to environmental tobacco smoke (ETS), except for total nicotine equivalents (TNE), which was significantly higher in non-smokers exposed to environmental tobacco smoke compared with study participants who never smoked. The results obtained from SRM 3671 and SRM 3672 could inform a potential certification of additional biomarkers of exposure to tobacco products in those standard reference materials.

Assessment of Tobacco Exposure During Pregnancy by Meconium Analysis and Maternal Interview

Smoking during pregnancy can have serious obstetric and fetal complications. Therefore, it is essential to identify in utero exposure to tobacco, being meconium the matrix of choice for this purpose. Meconium (n = 565) was analyzed for nicotine, cotinine and hydroxycotinine by LC-MS-MS. Then, tobacco meconium results were compared with smoking habits during pregnancy and neonatal outcomes measures (birth weight, length, head circumference, gestational age and Apgar scores). Although meconium analysis increased identification of in-utero exposure to tobacco (17.7% meconium positive specimens vs 13.5% mothers admitting tobacco use during pregnancy), there was a statistically significant relationship between meconium results and interview answers (P < 0.001). Birth weight was significantly lower for newborns with meconium positive results in males (P = 0.023) and females (P = 0.001), while for length significance was only observed in females (P = 0.001); however, when excluding meconium specimens positive for other drugs, a statistically significant difference was only found for female weight (P = 0.045). Meconium analysis proved to be more reliable for tobacco prenatal exposure detection than maternal interview. In addition, positive meconium results increased the probability for low birth weight, especially in females.

In utero and childhood exposure to tobacco smoke and multi-layer molecular signatures in children

BACKGROUND

The adverse health effects of early life exposure to tobacco smoking have been widely reported. In spite of this, the underlying molecular mechanisms of in utero and postnatal exposure to tobacco smoke are only partially understood. Here, we aimed to identify multi-layer molecular signatures associated with exposure to tobacco smoke in these two exposure windows.

METHODS

We investigated the associations of maternal smoking during pregnancy and childhood secondhand smoke (SHS) exposure with molecular features measured in 1203 European children (mean age 8.1 years) from the Human Early Life Exposome (HELIX) project. Molecular features, covering 4 layers, included blood DNA methylation and gene and miRNA transcription, plasma proteins, and sera and urinary metabolites.

RESULTS

Maternal smoking during pregnancy was associated with DNA methylation changes at 18 loci in child blood. DNA methylation at 5 of these loci was related to expression of the nearby genes. However, the expression of these genes themselves was only weakly associated with maternal smoking. Conversely, childhood SHS was not associated with blood DNA methylation or transcription patterns, but with reduced levels of several serum metabolites and with increased plasma PAI1 (plasminogen activator inhibitor-1), a protein that inhibits fibrinolysis. Some of the in utero and childhood smoking-related molecular marks showed dose-response trends, with stronger effects with higher dose or longer duration of the exposure.

CONCLUSION

In this first study covering multi-layer molecular features, pregnancy and childhood exposure to tobacco smoke were associated with distinct molecular phenotypes in children. The persistent and dose-dependent changes in the methylome make CpGs good candidates to develop biomarkers of past exposure. Moreover, compared to methylation, the weak association of maternal smoking in pregnancy with gene expression suggests different reversal rates and a methylation-based memory to past exposures. Finally, certain metabolites and protein markers evidenced potential early biological effects of postnatal SHS, such as fibrinolysis.

Opportunities for evaluating chemical exposures and child health in the United States: the Environmental influences on Child Health Outcomes (ECHO) Program

The Environmental Influences on Child Health Outcomes (ECHO) Program will evaluate environmental factors affecting children's health (perinatal, neurodevelopmental, obesity, respiratory, and positive health outcomes) by pooling cohorts composed of >50,000 children in the largest US study of its kind. Our objective was to identify opportunities for studying chemicals and child health using existing or future ECHO chemical exposure data. We described chemical-related information collected by ECHO cohorts and reviewed ECHO-relevant literature on exposure routes, sources, and environmental and human monitoring. Fifty-six ECHO cohorts have existing or planned chemical biomonitoring data for mothers or children. Environmental phenols/parabens, phthalates, metals/metalloids, and tobacco biomarkers are each being measured by ≥15 cohorts, predominantly during pregnancy and childhood, indicating ample opportunities to study child health outcomes. Cohorts are collecting questionnaire data on multiple exposure sources and conducting environmental monitoring including air, dust, and water sample collection that could be used for exposure assessment studies. To supplement existing chemical data, we recommend biomonitoring of emerging chemicals, nontargeted analysis to identify novel chemicals, and expanded measurement of chemicals in alternative biological matrices and dust samples. ECHO's rich data and samples represent an unprecedented opportunity to accelerate environmental chemical research to improve the health of US children.

Exposure to tobacco smoke and validation of smoking status during pregnancy in the MIREC study

Given that prenatal exposure to tobacco smoke can lead to increased risks of adverse health effects, having valid measures of exposure is important. In a Canadian cohort (n = 2000), maternal and infant biospecimens were analysed for cotinine. Sensitivity and specificity of self-reported active smoking status were estimated. Regression modelling was used to identify potential predictors of maternal and infant plasma cotinine in non-smoking women. During the first trimester, 60.6% of the women reported never smoking, 27.3% were former smokers, 6.1% had quit when they found out they were pregnant, 5.8% were smokers and 42% of the non-smokers reported exposure to secondhand smoke (SHS). Low detection of tobacco biomarkers in meconium limited its ability to identify exposure to SHS. The sensitivity and specificity for self-reported smoking during the 1st trimester were 85.37 and 99.45%, respectively. The lowest sensitivity was found in participants with the highest level of education and income, oldest women and those born outside Canada. Non-smoking women living in an apartment had 1.7 times higher odds of detectable plasma cotinine than those living in a single home after adjusting for other variables. Our results suggest that while self-reports are fairly accurate, they may be less so in populations with higher socio-economic status. This investigation underscores the need to consider the participant socio-economic characteristics and dwelling type when using questionnaires to estimate active and passive tobacco exposure.

Maternal hair testing to disclose self-misreporting in drinking and smoking behavior during pregnancy

This study aimed to objectively verify smoking and drinking behavior during pregnancy and to disclose self-misreporting through maternal hair analysis. A total of 153 women attending a university hospital in Barcelona (Spain) were selected and interviewed after delivery, on their smoking and drinking habits during pregnancy. A 9-cm hair strand was collected and analyzed by liquid chromatography tandem mass spectrometry for the presence of nicotine (NIC) and ethyl glucuronide (EtG) as biomarkers of tobacco and alcohol consumption, respectively. Concentrations of EtG <7 pg/mg hair and ≥30 pg/mg hair in the 0-3-cm hair segment have been used to assess, respectively, total abstinence and chronic excessive consumption in the previous 3 months, with repetitive moderate drinking lying in the interval 7-30 pg EtG per mg hair. Hair NIC less than 1 ng/mg hair indicates non-exposure to tobacco smoke while hair NIC indicates daily active smoking. In the interview, 28.1% of women declared to have smoked occasionally during gestation, while only 2.6% stated to have consumed alcohol on more than one occasion during pregnancy. Hair testing of smoking biomarkers disclosed that 7.2% of women remained active smokers during the whole pregnancy (hair NIC: 3.21-56.98 ng/mg hair), 16.3% were passive non-smokers or occasional smokers (hair NIC: 1.04-2.99 ng/mg hair), while 76.5% were not exposed to any cigarette smoke (hair NIC < limit of quantification - 0.91 ng/mg hair). Conversely, alcohol hair biomarkers showed that only 35.3% of women were totally abstinent during gestation (hair EtG: 3.89-6.73 pg/mg hair), while 62.7% drank a non-negligible amount of alcohol during pregnancy (hair EtG: 7.06-26.57 pg/mg hair), and 2% were chronic excessive drinkers (hair EtG: 35.33-47.52 pg/mg hair). Maternal hair analysis has shown to be significantly more sensitive than interviews in revealing an alarming misreported prevalence of alcohol use during pregnancy. These findings stress the need to use objective measures to assess alcohol exposure and to consider the inclusion of targeted actions to reduce alcohol consumption in maternal-child health policies.

Maternal smoking during pregnancy and offspring overweight: is there a dose-response relationship? An individual patient data meta-analysis

BACKGROUND/OBJECTIVES

A number of meta-analyses suggest an association between any maternal smoking in pregnancy and offspring overweight obesity. Whether there is a dose-response relationship across number of cigarettes and whether this differs by sex remains unclear.

SUBJECT/METHODS

Studies reporting number of cigarettes smoked during pregnancy and offspring BMI published up to May 2015 were searched. An individual patient data meta-analysis of association between the number of cigarettes smoked during pregnancy and offspring overweight (defined according to the International Obesity Task Force reference) was computed using a generalized additive mixed model with non-linear effects and adjustment for confounders (maternal weight status, breastfeeding, and maternal education) and stratification for sex.

RESULTS

Of 26 identified studies, 16 authors provided data on a total of 238,340 mother-child-pairs. A linear positive association was observed between the number of cigarettes smoked and offspring overweight for up to 15 cigarettes per day with an OR increase per cigarette of 1.03, 95% CI = [1.02-1.03]. The OR flattened with higher cigarette use. Associations were similar in males and females. Sensitivity analyses supported these results.

CONCLUSIONS

A linear dose-response relationship of maternal smoking was observed in the range of 1-15 cigarettes per day equally in boys and girls with no further risk increase for doses above 15 cigarettes.

Risk assessment of environmental exposure to heavy metals in mothers and their respective infants

Exposure to heavy metals can cause renal injury, which has been well documented in occupational exposure. Studies of low exposure in the general population, however, are still scarce, particularly for vulnerable populations such as mothers and young children. This study evaluated exposure to heavy metals, and biomarkers of renal function and oxidative stress in 944 lactating mothers and their infants and investigated the role of the interaction between heavy metals and oxidative stress in altering renal function. Mother and infant urine samples were analyzed to measure mercury (Hg), cadmium (Cd), and lead (Pb) concentrations for determining body-burden exposure; N-acetyl-β-d-glucosaminidase (NAG), α₁-microglobulin (α₁-MG), albumin (ALB), and creatinine (Cr) concentrations for determining early renal injury; and 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) concentrations for determining oxidative stress. The median concentrclearlyations in mothers presented as μg/g Cr (infants as μg/l) for Hg, Cd, and Pb were 0.695 (0.716), 0.322 (0.343), and 3.97 (5.306) respectively. The mothers and their infants had clearly been exposed to heavy metals and had levels higher than the reference values reported for the general populations of USA, Germany, and Canada. Multiple regression analyses clearly demonstrated associations between urinary heavy metals in quartiles and several renal and oxidative biomarkers in mothers and to a lesser extent their infants. ß coefficients for urinary excretions of MDA, 8-OHdG, ALB, α₁-MG, NAG, and Cr in mothers were high in the highest quartile of Hg (1.183-51.29μg/g Cr or 1.732-106.95μg/l), Cd (0.565-765.776μg/g Cr or 0.785-1347.0μg/l), and Pb (6.606-83.937μg/g Cr or 9.459-80.826μg/l), except Pb was not associated with ALB. Infants in the highest Pb quartile (9.293-263.098μg/l) had the highest ß coefficients of urinary excretion of MDA, 8-OHdG, ALB, NAG, and Cr. Significant increasing trend in biomarkers across the quartiles of the three metals was seen in both mothers and infants (p_trend <0.001). A receiver operating characteristic analysis supported the predictive abilities of the four renal biomarkers in discriminating between low versus high metal quartiles. The interaction between heavy metals and oxidative stress contributed to the high excretions of renal biomarkers, but the mechanism remains unclear. These findings add to the limited evidence that low exposure to heavy metals in the general population is associated with alterations in renal function that could eventually progress to renal damage if exposure continues and that children are more susceptible due to the immaturity of their body organs.

Tobacco, e-cigarettes, and child health

PURPOSE OF THE REVIEW

The availability of the Children's Health Exposure Assessment Resource funded by the National Institute of Environmental Health Sciences provides new opportunities for exploring the role of tobacco smoke exposure in causing harm to children.

RECENT FINDINGS

Children of smokers are exposed to nicotine and other harmful tobacco smoke chemicals in utero as well as in their environment. This passive exposure to tobacco smoke has a variety of negative effects on children. In-utero exposure to tobacco smoke causes poor birth outcomes and influences lung, cardiovascular, and brain development, placing children at increased risk of a number of adverse health outcomes later in life, such as obesity, behavioral problems, and cardiovascular disease. Furthermore, most smokers start in their adolescence, an age of increased nicotine addiction risk. Biomarkers of tobacco exposure helps clarify the role tobacco chemicals play in influencing health both in childhood and beyond. Although electronic cigarettes (e-cigarettes) appear to be a nicotine delivery device of reduced harm, it appears to be a gateway to the use of combustible cigarette smoking in adolescents.

SUMMARY

Pediatric researchers interested in elucidating the role of tobacco smoke exposure in adverse outcomes in children should incorporate biomarkers of tobacco exposure in their studies.

Prenatal exposure to tobacco smoke leads to increased mitochondrial DNA content in umbilical cord serum associated to reduced gestational age

We investigated if prenatal exposures to tobacco smoke lead to changes in mitochondrial DNA content (mtDNA) in cord serum and adversely affect newborns' health. Umbilical cord serum cotinine levels were used to determine in utero exposure to smoking. Cord serum mtDNA was measured by quantitative polymerase chain reaction analysis of the genes coding for cytochrome c oxidase1 (MT-CO1) and cytochrome c oxidase2 (MT-CO2). Log transformed levels of mtDNA coding for MT-CO1 and MT-CO2 were significantly higher among infants of active smokers with higher serum level of cotinine (p < 0.05) and inversely associated with gestational age (p = 0.08; p = 0.02). Structural equation modeling results confirmed a positive association between cotinine and MT-CO1 and2 (p < 0.01) and inverse associations with gestational age (p = 0.02) and IGF-1 (p < 0.01). We identified a dose-dependent increase in the level of MT-CO1 and MT-CO2 associated to increased cord serum cotinine and decreased gestational age.

Breast Milk and Hair Testing to Detect Illegal Drugs, Nicotine, and Caffeine in Donors to a Human Milk Bank

BACKGROUND

The use of illegal drugs and tobacco is an exclusion criteria for accepting a nursing mother as a milk donor. The detection window for human milk testing is typically a few hours. Hair testing has been considered the gold standard to assess chronic exposure to these toxic substances.

OBJECTIVE

The aim of this study was to determine the levels of illegal drugs, nicotine, and caffeine in breast milk and hair samples from donors to assess whether these substances were being used during the donation period and the months leading up to it.

METHODS

Thirty-six samples of hair and breast milk were obtained from 36 donors. The tests performed identified nicotine, caffeine, morphine, cocaine, cannabis, amphetamines, codeine, methadone, and other substances derived therefrom.

RESULTS

No illegal drugs were found in any of the samples analyzed. Nicotine and cotinine were found in 33.3% (12/36) of all hair samples. Among these 12 samples, 10 had cotinine concentrations consistent with cutoff values for unexposed nonsmokers, 1 had concentrations consistent with cutoff values for passive smokers, and 1 had concentrations consistent with cutoff values for active smokers. Caffeine was found in 77.7% of the hair samples and in 50% of the donor milk samples. The correlation for caffeine between donor milk and hair samples was r = 0.288, P = .0881.

CONCLUSION

Donors do not use illegal drugs during either the donation period or the months leading up to it. They are occasionally exposed to tobacco smoke and almost all of them consume caffeine.

Direct screening of tobacco indicators in urine and saliva by Atmospheric Pressure Solid Analysis Probe coupled to quadrupole-time of flight mass spectrometry (ASAP-MS-Q-TOF-)

A new screening method has been explored for direct analysis of tobacco smoke biomarkers in biological matrices (i.e., saliva and urine). Single run analysis using Atmospheric pressure Solid Analysis Probe (ASAP) and high resolution mass spectrometry with quadrupole and time of flight detector has been applied directly to some biological samples (i.e., urine and saliva), providing a fast, efficient and sensitive method of identification. The method has been applied to saliva and urine samples from heavy tobacco smokers for exposure studies. Nicotine itself, nicotine metabolites (i.e., cotinine, trans-3'-hydroxycotinine, nicotine-N-glucuronide) and other related tobacco smoke toxic compounds (i.e., NNK 4-[methyl(nitroso)amino]-1-(3-pyridinyl)-1-butanone, anatabine) were found in the analyzed samples. The identification of compounds was confirmed by ultrahigh performance liquid chromatography with MS-triple quadrupole detector after sample treatment. Different temporal trends and biomarkers behavior have been found in time series related samples. Both methods are compared for screening of these biological matrices.

Screening for secondhand smoke in schoolchildren in Japan

BACKGROUND

There is no systematic screening for secondhand smoke exposure in children.

METHODS

In 2002, we began a secondhand smoke screening (SSS) program for grade 4 elementary schoolchildren with the cooperation of public administration. The SSS program consisted of urinary cotinine measurement in children and a questionnaire survey of their parents.

RESULTS

More than 1200 schoolchildren were enrolled in this program annually. The level of urinary cotinine in 30% of the children was >5 ng/mL, whereas in half of them it was undetectable. The major risk factor affecting cotinine level was mother's smoking. Average cotinine was significantly high in children who had a history of "short stature", "decayed tooth and/or periodontal disease," and "frequent stridor". In addition, the highest level of cotinine was detected in children whose father and/or mother smoked in the living room and the lowest level of cotinine was detected in children whose father and/or mother smoked on the veranda or outside the door. These levels, however, were two-fivefold higher than in children whose parents did not smoke. On follow-up questionnaire survey 4 years after initial SSS, significant elevated motivation for smoking cessation was noted.

CONCLUSIONS

The SSS program is a very simple mass screen that can be done using only a urine test and is very effective for motivating parents to stop smoking with regard to cost benefit.

Assessments of endothelial function and arterial stiffness are reproducible in patients with COPD

Background

Elevated cardiovascular disease risk is observed in patients with COPD. Non-invasive assessments of endothelial dysfunction and arterial stiffness have recently emerged to provide mechanistic insight into cardiovascular disease risk in COPD; however, the reproducibility of endothelial function and arterial stiffness has yet to be investigated in this patient population.

Objectives

This study sought to examine the within-day and between-day reproducibility of endothelial function and arterial stiffness in patients with COPD.

Methods

Baseline diameter, peak diameter, flow-mediated dilation, augmentation index, augmentation index at 75 beats per minute, and pulse wave velocity were assessed three times in 17 patients with COPD (six males, eleven females, age range 47–75 years old; forced expiratory volume in 1 second =51.5% predicted). Session A and B were separated by 3 hours (within-day), whereas session C was conducted at least 7 days following session B (between-day). Reproducibility was assessed by: 1) paired t-tests, 2) coefficients of variation, 3) coefficients of variation prime, 4) intra-class correlation coefficient, 5) Pearson’s correlations (r), and 6) Bland–Altman plots. Five acceptable assessments were required to confirm reproducibility.

Results

Six out of six within-day criteria were met for endothelial function and arterial stiffness outcomes. Six out of six between-day criteria were met for baseline and peak diameter, augmentation index and pulse wave velocity, whereas five out of six criteria were met for flow-mediated dilation.

Conclusion

The present study provides evidence for within-day and between-day reproducibility of endothelial function and arterial stiffness in patients with COPD.

Recent advances in MS methods for nicotine and metabolite analysis in human matrices: clinical perspectives

Tobacco smoking is a major global health issue and represents the leading cause of preventable death in the developed countries. Nicotine is a major alkaloid found in tobacco products and its detection with its metabolites in human matrices is generally used for assessing tobacco consumption and second hand exposure. Several analytical techniques have been developed for the detection of nicotine and its metabolites, and MS coupled with chromatography is considered the standard reference method because of its superior sensitivity and specificity. In this work, we reviewed nicotine metabolism, clinical MS and the latest (2009-2014) development of MS-based techniques for measurement of nicotine and metabolites in human matrices. Appropriate biomarker and matrix selection are also critically discussed.

Maternal and neonatal hair and breast milk in the assessment of perinatal exposure to drugs of abuse

Perinatal exposure to one or more drugs of abuse can affect the neonate temporarily or permanently. In addition to meconium, the evaluation of perinatal exposure to drugs of abuse has been achieved by testing biological matrices coming from the newborn (neonatal hair) and from the pregnant or nursing mother (maternal hair and breast milk). These matrices have the advantage of noninvasive collection and account for a sizable time window of active and passive exposure. Sensitive and specific analytical methods are required to determine minute amounts of drugs of abuse and metabolites in these matrices. The present manuscript reviews the newest analytical methods developed to detect drugs of abuse as well as ethanol biomarkers in maternal and neonatal hair and breast milk.

Effect of a family-centered, secondhand smoke intervention to reduce respiratory illness in indigenous infants in Australia and New Zealand: a randomized controlled trial

INTRODUCTION

Secondhand smoke (SHS) is a significant cause of acute respiratory illness (ARI) and 5 times more common in indigenous children. A single-blind randomized trial was undertaken to determine the efficacy of a family centered SHS intervention to reduce ARI in indigenous infants in Australia and New Zealand.

METHODS

Indigenous mothers/infants from homes with ≥ 1 smoker were randomized to a SHS intervention involving 3 home visits in the first 3 months of the infants' lives (plus usual care) or usual care. The primary outcome was number of ARI-related visits to a health provider in the first year of life. Secondary outcomes, assessed at 4 and 12 months of age, included ARI hospitalization rates and mothers' report of infants' SHS exposure (validated by urinary cotinine/creatinine ratios [CCRs]), smoking restrictions, and smoking cessation.

RESULTS

Two hundred and ninety-three mother/infant dyads were randomized and followed up. Three quarters of mothers smoked during pregnancy and two thirds were smoking at baseline (as were their partners), with no change for more than 12 months. Reported infant exposure to SHS was low (≥ 95% had smoke-free homes/cars). Infant CCRs were higher if one or both parents were smokers and if mothers breast fed their infants. There was no effect of the intervention on ARI events [471 intervention vs. 438 usual care (reference); incidence rate ratio = 1.10, 95% confidence intervals (CI) = 0.88-1.37, p = .40].

CONCLUSIONS

Despite reporting smoke-free homes/cars, mothers and their partners continue to smoke in the first year of infants' lives, exposing them to SHS. Emphasis needs to be placed on supporting parents to stop smoking preconception, during pregnancy, and postnatal.

Use of meconium in perinatal epidemiology: potential benefits and pitfalls

PURPOSE

Meconium is a biomarker matrix that can be used to assess cumulative exposures in epidemiologic studies of prenatal risk factors. Depending on when meconium is collected, different exposure windows during pregnancy can be measured. However, little guidance exists regarding the extent to which timing of meconium collection will influence resulting effect estimates.

METHODS

We performed a simulation study of prenatal tobacco smoke exposure (assessed from meconium nicotine) and birth weight. We discuss four typical meconium collection methods capturing different exposure windows and assess the biases induced by these methods.

RESULTS

In simulations assuming that exposure to tobacco smoke only during late gestation was of etiologic relevance to birth weight, use of a meconium collection method that captured exposure windows other than late gestation resulted in biased estimates of the true nicotine-birth weight association.

CONCLUSIONS

Using meconium collection methods that do not reflect an exposure window of etiologic relevance can lead to biased results and erroneous conclusions regarding the nature of prenatal exposure-outcome associations. Understanding how prenatal exposure patterns vary across the pregnancy and exposure windows of etiologic relevance is essential in determining when and how to collect meconium for use in biomarker studies of prenatal exposure.

Transgenerational exposure to environmental tobacco smoke

Traditionally, nicotine from second hand smoke (SHS), active or passive, has been considered the most prevalent substance of abuse used during pregnancy in industrialized countries. Exposure to environmental tobacco smoke (ETS) is associated with a variety of health effects, including lung cancer and cardiovascular diseases. Tobacco is also a major burden to people who do not smoke. As developing individuals, newborns and children are particularly vulnerable to the negative effects of SHS. In particular, prenatal ETS has adverse consequences during the entire childhood causing an increased risk of abortion, low birth weight, prematurity and/or nicotine withdrawal syndrome. Over the last years, a decreasing trend in smoking habits during pregnancy has occurred, along with the implementation of laws requiring smoke free public and working places. The decrease in the incidence of prenatal tobacco exposure has usually been assessed using maternal questionnaires. In order to diminish bias in self-reporting, objective biomarkers have been developed to evaluate this exposure. The measurement of nicotine and its main metabolite, cotinine, in non-conventional matrices such as cord blood, breast milk, hair or meconium can be used as a non-invasive measurement of prenatal SMS in newborns. The aim of this review is to highlight the prevalence of ETS (prenatal and postnatal) using biomarkers in non-conventional matrices before and after the implementation of smoke free policies and health effects related to this exposure during foetal and/or postnatal life.

Prenatal tobacco exposure and cotinine in newborn dried blood spots

BACKGROUND

Tobacco smoking by pregnant women is a major public health hazard with both short- and long-term effects on offspring. This study describes the presence and level of the nicotine metabolite cotinine in newborn dried blood spots (DBS) and compares it with the reported maternal smoking recorded on state birth registries. We hypothesize that cotinine in DBS may be a useful measure of newborn in utero tobacco exposure.

METHODS

An observational, cross-sectional study of 1414 DBS obtained from California, Michigan, New York, and Washington newborn screening programs was carried out. Cotinine levels in DBS were quantified by liquid chromatography tandem mass spectrometry analysis and compared with maternal smoking as reported in vital statistics data.

RESULTS

Cotinine ≥0.3 ng/g was detected in 35% of newborn DBS, including DBS of 29% of newborns whose mothers reportedly did not smoke cigarettes during pregnancy, some of whom were presumably exposed to environmental tobacco smoke. Twelve percent of the newborn DBS had cotinine levels that were ≥9.0 ng/g (equivalent to 6 ng/mL plasma, a level that indicates active smoking of the mother), although 41% of the mothers of these infants reportedly did not smoke.

CONCLUSIONS

These data confirm that reported smoking during pregnancy is an imperfect measure of prenatal tobacco smoke exposure. Cotinine assessment in newborns may improve surveillance of tobacco use during pregnancy.

Assessment of unsuspected exposure to drugs of abuse in children from a Mediterranean city by hair testing

Hair testing was used to investigate the prevalence of unsuspected exposure to drugs of abuse in a group of children presenting to an urban paediatric emergency department without suggestive signs or symptoms. Hair samples were obtained from 114 children between 24 months and 10 years of age attending the emergency room of Hospital del Mar in Barcelona, Spain. Hair samples from the accompanying parent were also collected. The samples were analyzed for the presence of opiates, cocaine, amphetamines, and cannabinoids by ultra-performance liquid chromatography-tandem mass spectrometry. Parental sociodemographics and possible drug of abuse history were recorded. Hair samples from twenty-three children (20.1%) were positive for cocaine (concentration range 0.15–3.81 ng/mg hair), those of thirteen children (11.4%) to cannabinoids (Δ9-THC concentration range 0.05–0.54 ng/mg hair), with four samples positive to codeine (0.1–0.25 ng/mg hair), one positive for 2.09 ng methadone per mg hair and one to 6-MAM (0.42 ng/mg hair) and morphine (0. 15 ng/mg hair) . In 69.5 and 69.2% of the positive cocaine and cannabinoids cases respectively, drugs was also found in the hair of accompanying parent. Parental sociodemographics were not associated with children exposure to drugs of abuse. However, the behavioural patterns with potential harmful effects for the child’s health (e.g., tobacco smoking, cannabis, benzodiazepines and/or antidepressants use) were significantly higher in the parents of exposed children. In the light of the obtained results (28% overall children exposure to drugs of abuse) and in agreement with 2009 unsuspected 23% cocaine exposure in pre-school children from the same hospital, we support general hair screening to disclose exposure to drugs of abuse in children from risky environments to provide the basis for specific social and health interventions.

Instruments to assess secondhand smoke exposure in large cohorts of never smokers: the smoke scales

The objectives of this study were to: (i) to develop questionnaires that can identify never-smoking children and adults experiencing increased exposure to secondhand smoke (SHS+), (ii) to determine their validity against hair nicotine, and (iii) assess their reliability. A sample of 191 children (85 males; 106 females; 7–18 years) and 95 adult (23 males; 72 females; 18–62 years) never-smokers consented to hair nicotine analysis and answered a large number of questions assessing all sources of SHS. A randomly-selected 30% answered the questions again after 20–30 days. Prevalence of SHS+ in children and adults was 0.52±0.07 and 0.67±0.10, respectively (p<0.05). The Smoke Scale for Children (SS-C) and the Smoke Scale for Adults (SS-A) were developed via factor analysis and included nine questions each. Positivity criteria for SS-C and SS-A via receiver operating characteristics curve analysis were identified at >16.5 and >16, respectively. Significant Kappa agreement (p<0.05) was confirmed when comparing the SS-C and SS-A to hair nicotine concentration. Reliability analyses demonstrated that the SS-C and SS-A scores obtained on two different days are highly correlated (p<0.001) and not significantly different (p>0.05). Area under the curve and McNemar's Chi-square showed no pair-wise differences in sensitivity and specificity at the cutoff point between the two different days for SS-C and SS-A (p>0.05). We conclude that the SS-C and the SS-A represent valid, reliable, practical, and inexpensive instruments to identify children and adult never-smokers exposed to increased SHS. Future research should aim to further increase the validity of the two questionnaires.

High cotinine levels are persistent during the first days of life in newborn second hand smokers

BACKGROUND

Despite the adverse effects of maternal smoking during pregnancy on the newborn's health are well-known, in the pediatric population, a high prevalence exists that is very much affected by second hand smoke (SHS). This study aims to investigate the impact of maternal smoking habits during pregnancy on cotinine levels in newborns during the first days of life. The high association between cotinine concentration in maternal and umbilical cord blood (UCB) has been previously reported, but the levels of blood cotinine that remain in infants born to smokers is unknown.

METHODS

Cotinine concentration was measured in UCB, in maternal and newborn peripheral blood. Data from UCB sample dyads of ninety mothers and from seventy-one newborns were analyzed.

RESULTS

Cotinine levels were significantly different among non-smokers (9.9 ± 5.9 ng/ml), moderate (67.3 ± 7.4 ng/ml), and heavy smokers (137.7 ± 19.5 ng/ml) (p<0.0001). Significant correlations were found between maternal and UCB cotinine (r=0.748; p<0.001), and between UCB and newborn plasma cotinine at 48 h after birth (r=0.541; p<0.001). The smokers exposed their infants to cotinine with a median of 31.7 ± 8.6 ng/ml (moderate) or 59.1 ± 13.3 ng/ml (heavy smokers) until at least, 48 h after birth. Reduced birth weight and length were significantly related with UCB cotinine levels.

CONCLUSIONS

A positive association between UCB and plasmatic cotinine in newborns was found. The high cotinine levels detected in newborns from smoker mothers indicates that their infants are subjected to elevated SHS from birth. These results can help to reinforce the awareness of the adverse effects of smoking during pregnancy.

Prenatal nicotine exposure and child behavioural problems

In utero exposure to tobacco smoke has been related to numerous adverse health effects in new-borns, infants, children, adolescents and adults. The aim of this review was to summarise findings on prenatal nicotine exposure and its relationship with behavioural problems in the offspring. The majority of studies, and especially several recent epidemiological studies, observed a higher likelihood for attention-deficit/hyperactivity disorder (ADHD) or ADHD symptoms in exposed subjects. However, both human and animal studies have failed to provide clear evidence on causality. Existing literature on studies investigating the association between prenatal nicotine exposure and conduct or externalising problems in the offspring suggests a causal effect. The establishment of a final conclusion concerning the relationship between prenatal nicotine exposure and internalising problems in the offspring is complicated by insufficient data and mixed results in epidemiological studies. Prenatal nicotine exposure has been associated with altered brain structure and function in human offspring, and a proposed biological mechanism is related to nicotine's adverse influence on neurotransmitter systems during brain development. In conclusion, establishing a statement on the causality of the relationship between prenatal nicotine exposure and behavioural problems in children remains a challenging task. Nevertheless, considering the results of an increasing number of studies which link prenatal exposure to nicotine to externalising problems applying different methodologies to account for confounding and in view of other adverse health effects known to be caused by this exposure, parents should consider smoking cessation.

Prenatal exposure to substance of abuse: a worldwide problem

Substance abuse during pregnancy is an important public health issue affecting the mother and the growing infant. Preterm labor, miscarriage, abruption and postpartum hemorrhage are obstetric complications which have been associated with women who are dependent on abused substances. Moreover, women are also at an increased risk of medical problems such as poor nutrition, anemia, urinary tract infections as well as sexually transmitted infections, hepatitis, HIV and problems related to infection. Intrauterine growth restriction, prematurity, stillbirth, neonatal abstinence syndrome, and Sudden Infant Death Syndrome represent only some of fetal effects. Later on, during childhood, it has been shown that in utero exposure to substances of abuse is associated with increased rates of respiratory infections, asthma, ear and sinus infections. Moreover, these children are more irritable, have difficulty focusing their attention, and have more behavioral problems. Therefore, the assessment of in utero exposure to abused substance is extremely necessary and is relevant for the care of the mother and the offspring. In this sense, several approaches are possible; however, recently the evaluation of in utero exposure to abused drugs has been achieved by testing biological specimens coming from fetus or newborn, pregnant or nursing mother, or from both the fetus and the mother. Maternal and neonatal biological materials reflect exposure in a specific time period and each of them has different advantages and disadvantages in terms of accuracy, time window of exposure and cost/benefit ratio. The methodology for identification and determination of abused substances in biological materials are of great importance. Consequently, sensitive and specific bioanalytical methods are necessary to accurately measure biomarkers. Different immunoassays methods are used as screening methods for drug testing in the above reported specimens, however, the results from immunoassays should be carefully interpreted and confirmed by a more specific and sensitive chromatographic methods such as GC-MS or LC-MS. The interest in the development and optimization of analytical techniques to detect abused substances in different specimens is explained by the several possibilities and information that they can provide.

Tobacco smoke and pregnancy: segmental analysis of nicotine in maternal hair

The investigation assessed nicotine metabolism prior to and during pregnancy in relation to different maternal smoking habits. It included segmental hair analysis in 3 groups of postpartum women: 32 active smokers, 35 passive smokers, and 19 unexposed nonsmokers. Maternal hair at least 12 cm long was collected after delivery and was divided into four 3-cm-long segments representing each trimester of pregnancy and the 3 months prior to pregnancy. Hair nicotine concentration was determined by gas chromatography-mass spectrometry. Nicotine levels were the highest in the 3-month period before pregnancy and it gradually decreased with advancing gestation in all study groups. These results suggest that when assessing tobacco exposure as measured by nicotine in hair, metabolic changes of nicotine during pregnancy should be taken into consideration.

Assessment of prenatal exposure to tobacco smoke by cotinine in cord blood for the evaluation of smoking control policies in Spain

Background

Over the last few years a decreasing trend in smoking has occurred not only in the general population but also during pregnancy. Several countries have implemented laws requiring all enclosed workplace and public places to be free of second hand smoke (SHS). In Spain, legislation to reduce SHS was implemented in 2005. The present study examines the possible effect of this legislation on prenatal SHS exposure.

Methods

Mothers and newborns were recruited from 3 independent studies performed in Hospital del Mar (Barcelona) and approved by the local Ethics Committee: 415 participated in a study in 1996-1998, 283 in 2002-2004 and 207 in 2008. A standard questionnaire, including neonatal and sociodemographic variables,tobacco use and exposure during pregnancy, was completed at delivery for all the participants in the three study groups. Fetal exposure to tobacco was studied by measuring cotinine in cord blood by radioimmunoassay (RIA).

Results

32.8% of the pregnant women reported to smoke during pregnancy in 1996-1998, 25.9% in 2002-2004 and 34.1% in 2008. In the most recent group, the percentage of no prenatal SHS exposure (cord blood cotinine 0.2-1 ng/mL) showed an increase compared to the previous groups while the percentages of both: low (1.1-14 ng/mL) and very high (> 100 ng/mL) prenatal SHS exposure showed a decrease.

Discussion

The results of the three study periods (1996-2008) demonstrated a significant increase in the percentage of newborns free from SHS exposure and a decrease in the percentage of newborns exposed to SHS during pregnancy, especially at the very high levels of exposure. A significant maternal smoking habit was noted in this geographical area with particular emphasis on immigrant pregnant smoking women.

Conclusions

Our study indicates that there is a significant maternal smoking habit in this geographical area. Our recommendation is that campaigns against smoking should be directed more specifically towards pregnant women with particular emphasis on non-native pregnant smokers due to the highest prevalence of tobacco consumption in the immigrant women.

Nicotine and metabolites in paired umbilical cord tissue and meconium specimens

Umbilical cord tissue was studied as a means of detecting prenatal exposure to nicotine. This was accomplished by comparing the presence and concentration of nicotine as well as nicotine metabolites in both umbilical cord tissue and paired meconium samples with maternal smoking histories obtained by self-report. Nicotine and metabolites (cotinine, 3-hydroxycotinine, nornicotine, and anabasine) were detected and quantitated using liquid chromatography-tandem mass spectroscopy. Between June and September 2009, 19 women with a tobacco exposure history (either first- or second-hand tobacco smoke exposure during pregnancy) were consented for the study. A questionnaire was completed to document nicotine exposure during each trimester of pregnancy. All infants were delivered at term (38 weeks or greater) and paired umbilical cord tissue (10-cm segment or greater) and meconium were obtained. Nicotine and 3-hydroxycotinine were most prominent in meconium, whereas cotinine and 3-hydroxycotinine were most prominent in the umbilical cord. Concentrations of all three analytes were generally higher in meconium. Nornicotine was detected only in meconium, at very low concentrations, and anabasine was not detected in either specimen. All analyte concentrations were lowest when the mother stated she quit smoking early in pregnancy or had only second-hand exposure, and detection was poor if exposure was limited to the first or second trimesters. Although different nicotine and metabolite patterns exist in meconium versus umbilical cord tissue, this work indicates that either specimen can be used to detect third-trimester fetal nicotine exposure.

Measurement of nicotine, cotinine and trans-3'-hydroxycotinine in meconium by liquid chromatography-tandem mass spectrometry

Nicotine (NIC), cotinine (COT) and trans-3'-hydroxycotinine (OHCOT) are the most prevalent and abundant tobacco biomarkers in meconium. We have developed and validated an accurate and precise method for the measurement of these analytes in meconium in which potassium hydroxide is used to digest the meconium sample, followed by solid phase extraction from the liquified sample. The precision of OHCOT, COT and NIC measurements (intra-day and inter-day) were 4.8-10.6%, 3.4-11.6% and 9.3-15.8%, respectively. Evaluation of accuracy indicated bias of -4.0, 2.0 and 0.8% for OHCOT at concentrations of 0.5, 2.5 and 7.5 ng/g. The accuracy estimates for COT at concentrations of 0.5, 2.5 and 7.5 ng/g are 4.0, 4.0 and 5.7%, respectively. For NIC at 2, 10 and 30 ng/g the accuracy was calculated to be 3.0, 5.0 and 5.1%, respectively. The linear range of standard solutions was 0.125-37.5 ng/mL for OHCOT and COT, and 0.75-150 ng/mL for NIC. This method was applied to the analysis of 374 meconium samples from infants of both smoking and nonsmoking mothers. Positive correlations with r(2)≥0.63 were observed between NIC and COT, COT and OHCOT, NIC and OHCOT, and NIC and (OHCOT+COT) in these samples.