Measuring the exposure of infants to tobacco smoke. Nicotine and cotinine in urine and saliva

Development of a simple and rapid elisa of urinary cotinine for epidemiological application

Highly stereospecific polyclonal antibodies (anti-CN) to cotinine (CN), a major metabolite of nicotine, were prepared from rabbit antisera to CN-linked keyhole limpet hemocyanin (KLH) by removing the antibodies to KLH and to its binding regions of CN. This was achieved by using immunoadsorbents consisting of insolubilized KLH onto CNBr-activated-Sepharose 4B. A new simple and rapid enzyme-linked immunosorbent assay (ELISA) of urinary CN was developed using the anti-CN. A brief outline of the method is as follows: CN-bovine thyroglobulin complex is coated onto wells of microtiter plates (1 ng/well), and then aliquots of urine samples or standard CN solutions were added followed by appropriate dilution of the anti-CN. The bound anti-CN antibodies are quantified spectrophotometrically with horseradish peroxidase-labelled anti-rabbit IgG and 2,2'-azino-di (3-ethylbenz- thiazoline)-6-sulfonic acid. Measurement of CN concentration in urine samples can be read off on a calibration curve drawn by using standard CN solutions. The standard curve ranged from 1 ng to 4 μ g /ml with an estimated lower limit of sensitivity of 7-8 ng/ml, resulting in within/between-assay CV (coefficient of variation) of lower than 10%. The method allowed one to assay more than 40 samples in duplicate by using just one plate, and is thus easily applicable to epidemiological investigations into exposure status to tobacco smoke.

The burden of environmental tobacco smoke exposure on the respiratory health of children 2 months through 5 years of age in the United States: Third National Health and Nutrition Examination Survey, 1988 to 1994

OBJECTIVE

To measure the effect of environmental tobacco smoke (ETS) on respiratory health in a national sample of young children.

METHODS

The study evaluated children 2 months through 5 years of age participating in the Third National Health and Nutrition Examination Survey, 1988 to 1994. The group was a representative sample of the US population (N = 7680). A parental report of household smoking or maternal smoking during pregnancy ascertained ETS exposure. Respiratory outcomes were based on parental report of wheezing, cough, upper respiratory infection, or pneumonia in the last 12 months and chronic bronchitis or physician-diagnosed asthma at any time. Logistic regression was used to adjust for age, sex, race/ethnicity, birth weight, day care, family history of allergy, breastfeeding, education level of head of household, and household size.

RESULTS

Approximately 38% of children were presently exposed to ETS in the home, whereas 23.8% were exposed by maternal smoking during pregnancy. ETS exposure increased chronic bronchitis and three or more episodes of wheezing among children 2 months to 2 years old and asthma among children 2 months to 5 years old. For household exposure, a consistent effect was seen only at >/=20 cigarettes smoked per day. Adjusted odds ratios for increased risk (95% confidence interval) for household exposures (>/=20 cigarettes smoked per day vs none smoked) and maternal prenatal exposure (prenatal smoking vs no smoking), respectively, for children 2 months to 2 years old were chronic bronchitis, 2.5 (1.6, 4.1); 2.2, (1.6, 3); three or more episodes of wheezing, 2.7 (1.7, 4.2), 2.1 (1. 5, 2.9); and for children 2 months to 5 years old were asthma, 2.1 (1.4, 3.2); 1.8 (1.3, 2.6). Reported use within the past month of prescription medications for asthma (beta-agonists or inhaled steroids) was not different between those with asthma reporting ETS exposure and those reporting no exposure; percent of patients with asthma reporting use of medication by household exposure was 0, 25. 7%; 1 to 19 cigarettes smoked per day, 32.9%; and >/=20 cigarettes smoked per day, 23.1%; percent of patients with asthma reporting use of medication by maternal smoking during pregnancy was no, 28.9%; yes, 22.7%. Among children 2 months to 2 years of age exposed to ETS, 40% to 60% of the cases of asthma, chronic bronchitis, and three or more episodes of wheezing were attributable to ETS exposure. For diagnosed asthma among children 2 months through 5 years old, there were 133 800 to 161 600 excess cases. Among exposed children 2 months through 2 years of age, there were 61 000 to 79 200 excess cases of chronic bronchitis and 126 700 to 172 000 excess cases of three or more episodes of wheezing.

CONCLUSIONS

ETS exposure is common among children in the United States. The reported prevalence of asthma, wheezing, and chronic bronchitis was increased with ETS exposures. No statistically significant increase in the prevalence of upper respiratory infection, pneumonia, or cough was associated with ETS exposure. ETS exposure has little effect on the respiratory health of children between 3 and 5 years of age, with the exception of asthma. ETS appears to increase the prevalence of asthma rather than the severity as measured by medication use. These findings reinforce the need to reduce the exposure of young children to ETS.

Tobacco smoke habits in a group of adolescents: responsibility of the cohabitants in the active and passive exposure

Several studies in adults demonstrated a positive relationship between the number of cigarettes smoked and the urinary cotinine. The aim of this work was to analyze the passive and active smoking exposure of 333 sixteen-year-old students, demonstrated by their urinary cotinine, in comparison with the smoking habits of all the cohabitants. This last information was obtained from a questionnaire and urinary cotinine in mothers. The second purpose of this work was to observe whether the smoking habits of parents can promote the voluntary active exposure to tobacco smoke in children. The considered students represent a particular group of people (16 years old) having a life-style still strictly bound to the smoking habit of parents. In fact, the nonactive smokers show urinary cotinine levels described by the following means: 28.81, 39.35, 39.62, and 57.67 ng/mL. This finding demonstrates a trend of exposure from no exposure to a maximum level of passive exposure. Similar results can be observed by considering the urinary cotinine of mothers. Finally, the active smoking habit potentially acquired by the adolescents seems to be induced also by emulation of the smoking habits of fathers. This possibility is demonstrated by a light positive and statistically significative correlation with the number of cigarettes actively smoked and, consequently, with urinary cotinine.

Increased levels of the nicotine metabolite cotinine in schizophrenic smokers compared to other smokers

The purpose of this study was to determine if schizophrenic patients self-administer more nicotine during cigarette smoking than nonschizophrenic subjects. Urinary cotinine, a nicotine metabolite, was measured in 20 schizophrenic patients and 20 nonschizophrenic subjects with similar smoking history. Schizophrenic patients had significantly higher urinary cotinine levels, suggesting that schizophrenics consume higher doses of nicotine, probably by deeper inhalation of cigarettes. Schizophrenic patients' higher dose of nicotine may target different receptors than those activated by the lower doses self-administered by most nonschizophrenic smokers. In particular, high doses may activate low-affinity alpha-7 nicotinic receptors, associated with deficits in sensory inhibition in schizophrenia.

The internal dose of passive smoking at home depends on the size of the dwelling

As part of a longitudinal study two urine samples (survey 1 in 1991 and survey 2 in 1992) were collected from 602 elementary school children to investigate the relationship between urinary cotinine excretion (UCE) and the daily consumption of cigarettes at home (exposure). Size of the dwelling, educational level, and maternal smoking were taken into consideration as additional predictors. The history regarding parental smoking habits and confounding variables was ascertained by standardized questionnaires completed by the parents. Cotinine was measured using gas chromatography selected ion monitoring. UCE was expressed as cotinine/creatinine (ng/mg). In children with detectable UCE in survey 1 (35%) and in survey 2 (44%) the excretion ranged between 1.5 and 24.7 ng/mg (5-95%) and between 1.2 and 25.2 ng/mg, respectively. UCE measurements in both surveys were highly correlated (r = 0.65, P = 0.0001), and 59.6% of the UCE in survey 2 can be explained in linear regression by the UCE in survey 1. Using multiple linear regression, the categorized number of cigarettes reported to be consumed at home (20 cigarettes and more: 1991, P = 0.0001; 1992, P = 0.0003) and low educational level of the parents (P = 0.011 in 1991, P = 0.04 in 1992) were positively associated with UCE, whereas the size of the dwelling turned out to be negatively associated with UCE (P = 0.12 in 1991, P = 0.001 in 1992). In small dwellings (< or = 80 m2) the effect of exposure on UCE was much more pronounced. In conclusion, a single UCE measurement provides information which is widely stable within a yearly interval and is related to passive smoke history as well as to socio-economic status and the size of the dwelling. The latter variable should be considered as an effect modifier of exposure on internal dose and should be taken into account in future studies on passive smoke exposure.

Exposure of Puerto Rican children to environmental tobacco smoke

BACKGROUND

Many studies of environmental tobacco smoke (ETS) have been conducted in northern, industrialized countries. As yet, however, no studies have been carried out on ETS exposure with nonsmokers living in tropical environments.

METHODS

Urine specimens were collected from 175 healthy Puerto Rican children (2-11 years) living in an industrial area and were analyzed for cotinine, a quantitative biomarker for exposure to ETS. Their parents completed a questionnaire covering smoking habits.

RESULTS

Seventy percent of children were exposed to ETS. Quantitatively, exposure to smoke in households consuming more than 1 pack per day (ppd) caused a doubling of cotinine excretion compared with households consuming less than 1 ppd. Smoke from mothers made the greatest contribution to cotinine, followed by smoke from fathers, with smoke from other persons having no effect. Degree of exposure was inversely related to age of the child.

CONCLUSIONS

Young children (2-4 years) were detected to have significantly greater exposure to ETS than older children (5-11 years) and in the younger group the effect seemed to be from the mother's smoking much more than the father's, with other persons contributing negligible amounts. This suggests an obvious strategy for prevention of exposure to ETS in young children.

Biological monitoring of exposure to cadmium, a human carcinogen, as a result of active and passive smoking

Cadmium (Cd), a known human carcinogen, is one of the components of tobacco and also has many industrial uses. Smoking Cd-contaminated cigarettes at work may cause an increase in blood levels and toxicity of Cd. For a population of nonexposed workers, we compared blood Cd and urine cotinine (Cot) levels as biological markers of exposure to cigarette smoke of active smokers (AS) and passive smokers (PS) with those of unexposed nonsmokers (UNS) in 158 workers. The mean Cd in AS (0.097 microgram%; ie, 0.097 microgram/100 mL whole blood) was significantly higher than in UNS (0.085 microgram%), and was very close to the mean Cd levels in PS (0.093 microgram%). Mean Cd levels in exposed past smokers (0.105 microgram% was higher than in nonexposed past smokers (P < 0.05) and in AS. The mean Cot level was significantly higher in AS than in PS or in UNS. Increased smoking was associated directly with increased blood Cd and urine Cot. Our results supported and proved quantitatively that exposure to cigarette smoke is harmful to both AS and PS, as we show that in both cases there is an increase in blood Cd. According to our results, exposure to cigarette smoke via active and passive smoking increases blood Cd by an average of 0.01 micrograms% over the background (UNS). We conclude that exposure to cigarette smoke is a confounder to be taken into account when carrying out epidemiological studies and surveillance programs on workers exposed to Cd at work.

Features of infant exposure to tobacco smoke in a cohort study in Tasmania

STUDY OBJECTIVES

To document changes in smoking style around infants over time and to identify factors associated with the smoking hygiene of mothers and others.

DESIGN

A population based cohort study.

SETTING

Population based, involving 22% of live births in Tasmania, Australia.

PARTICIPANTS

From 1 May 1988 to 30 April, 1993, 6109 infants and their mothers (89% of eligible infants) participated in the hospital and home interview of the cohort study. Infants eligible for cohort entry were those assessed at birth to be at a higher risk of SIDS.

MAIN RESULTS

The overall proportion of mothers who smoked during pregnancy and postnatally did not decline. Increasing trends were found for mothers and others not smoking in the same room as baby or while holding or feeding the baby, significant over the five year period. Good smoking hygiene (mother not smoking in the same room as baby) was positively associated with--first birth (OR = 1.74 (1.30, 2.33)), low birth weight (1.69 (1.27, 2.23)), being born after 1 May 1991 (1.67 (1.33, 2.11)), and private health insurance status (1.39 (1.02, 1.90)). Good smoking hygiene was negatively associated with maternal smoking during pregnancy (0.50 (0.31, 0.80)), intention to bottle feed (0.62 (0.49, 0.78)), the level of maternal postnatal smoking, increasing numbers of smokers in the household, and parents cohabiting but unmarried. A similar analysis was conducted for other household residents who smoked.

CONCLUSIONS

Changes in maternal smoking prevalence have been small. The exposure of infants to tobacco smoke postnatally has decreased significantly, although a large proportion of infants are still exposed to tobacco smoke. The identification of the above parental and infant factors associated with good smoking hygiene should be useful for health education planning.

Evaluation of micronuclei in exfoliated urothelial cells and urinary thioether excretion of smokers

Mutagens are present in large quantities in the urine of cigarette smokers, thus, their urothelial cells may represent a possible target for absorbed and excreted mutagens. Our aim is to validate the micronucleus (MN) test in exfoliated urothelial cells obtained from urine samples of cigarette smokers. The urinary thioether (UT) test is also carried out on the same individuals in order to find out whether there is any correlation between these two end-points. The mean (+/- SE) MN frequency and UT determination is 1.93 (+/- 0.11)% and 9.71 (+/- 1.61) mmol SH/mol creatinine for 23 smokers, and 0.66 (+/- 0.05)% and 4.20 (+/- 0.56) mmol SH/mol creatinine for 20 nonsmokers. Our results show a higher frequency of micronucleated cells (p < 0.001) and higher excretion of UTs (p < 0.05) in smokers as compared to nonsmokers. Concentrations of UTs and MN frequencies increased with tobacco consumption. The MN frequencies showed only a marginal increase, not significant (p > 0.05), after passive smoking compared to nonsmoking values. There was no significant correlation between MN frequencies and UTs, either in smokers (r = 0.164, p > 0.05) or in nonsmokers (r = -0.018, p > 0.05). Our data demonstrate tobacco-induced chromosome damage in bladder tissue consistent with increased risk of cancer at this site among smokers.

Urinary cotinine in children and adults during and after semiexperimental exposure to environmental tobacco smoke

Urinary cotinine (U-cotinine) as a biomarker of environmental tobacco smoke exposure was evaluated in 14 children (age 4-11 y) and in 7 adults who were exposed to environmental tobacco smoke at an air nicotine level of 110 mg/m3 for 2 h in a bus. Nicotine in air and U-cotinine were measured by gas chromatography/mass spectrometry before, during, and after the experiment. U-cotinine rose rapidly to a maximum after a median of 6 h following the end of exposure; remained at an apparent plateau for half a day; and then decreased exponentially, with a mean half-time of 19 h (95% confidence interval 18-20 h; no significant difference between children and adults). The maximum U-cotinine was higher in the children (mean = 22 mg/l) than in the adults (13 mg/l; p = .005); decreased with age among the children (r = -.74; p = .002); and increased as the estimated inhaled nicotine dose increased. Therefore, the findings of the present study showed that young children had higher U-cotinine than adults at the same experimental environmental tobacco smoke exposure, probably because they had a higher relative nicotine dose because of a higher relative ventilation rate, and possibly also because of metabolic differences; the elimination rate did not differ. The long half-time makes U-cotinine a good biomarker of environmental tobacco smoke exposure; the time of sampling is not very critical. Dilution-adjusted concentrations should be employed, and in children, preferably by density correction. A certain urinary cotinine level indicates a lower environmental tobacco smoke exposure in a small child than in an adult.

Uptake of nicotine in hair during controlled environmental air exposure to nicotine vapour: evidence for a major contribution of environmental nicotine to the overall nicotine found in hair from smokers and non-smokers

Hair from smokers and non-smokers has been exposed in a dynamic exposure chamber to air nicotine concentrations ranging from 1.5 to 45 and from 20 to 2000 micrograms/m3 for 8 weeks and 72 hr, respectively. Accumulated hair nicotine was quantified by GC/MS. Hair was also collected for direct measurements of nicotine in 0-2, 2-4 and 4-6 cm segments from the scalp. Human hair showed a high affinity for air nicotine and the chamber experiments revealed a linear relationship between the initial hair uptake rates of nicotine and the duration of exposure at all air nicotine concentrations applied. Hair nicotine uptake rate decreased with time after 4 to 6 weeks exposure to 15 and 45 micrograms/m3 air concentrations of nicotine, but not to the 1.5 micrograms/m2 nicotine concentration. Ratio between the hair uptake rate of nicotine and the applied air concentration of nicotine decreased with increasing air concentrations of nicotine. Segment analysis of hair revealed an outward increasing gradient of nicotine in hair. Hair uptake pattern of air nicotine suggests the uptake to be governed by an equilibrium between nicotine in air and nicotine on the hair surface, possibly combined with a slower diffusion process of nicotine from the hair surface into the hair core. The hair segment analysis of nicotine indicates that environmental nicotine is the dominating contributor to the overall nicotine found in hair both from smokers and non-smokers.

Exposure to passive smoking during pregnancy and childhood, and cancer risk: the epidemiological evidence

There are relatively few studies on the association between environmental tobacco smoke (ETS) during pregnancy and childhood, and cancer in childhood, adolescence or adulthood. The associations between maternal smoking during pregnancy and childhood cancer have been studied intensively, but there is no clear association overall, or for specific sites. The association between childhood cancer and smoking by the father in the preconceptional period, and by either parent during the child's lifetime, has been little studied. Again, no clear associations have been identified. However, evidence from studies of exposure to known carcinogens from ETS, and of genotoxic effects indicates that any effect, if present, is expected to be weak, and therefore could not have been detected by most of the studies which have been performed, due to the small number of cases included. There is some consistency of association between ETS exposure in childhood and the risk of lung cancers in adulthood. There is therefore a need for further epidemiological studies on ETS exposure during pregnancy and childhood and the occurrence of cancers.

Urinary cotinine as a measure of passive smoke exposure in asthmatic children

This study sought to determine (1) the association between passive smoke exposure and acute symptoms in asthmatic children and (2) the association between parental report and objective measures of passive smoke exposure. Asthmatic children ages 3 to 11 were eligible for the study, which involved measurement of smoke exposure by questionnaire and by urine sample at a time of an acute asthma attack and then later when the child was symptom-free. High levels of passive smoke exposure were detected at both times in most children. Parental report of passive smoke exposure correlated with urinary measure of exposure.

Reducing tobacco smoke in the environment of the child with asthma: a cotinine-assisted, minimal-contact intervention

Children with asthma who are exposed to environmental tobacco smoke are at increased risk for adverse health consequences. An experimental design was used to evaluate a minimal-contact intervention aimed at modifying parents' smoking behavior in their homes. All subjects received counseling on the health effects of passive smoking and advice to quit smoking inside the home. Treatment subjects were also mailed the results of a urine cotinine test on their child and a self-help manual. More treatment (35%) than control (17%) subjects reported smoking outside their homes at posttest (and their children's cotinine levels were lower), but this difference was not statistically significant.

Bed sharing, smoking, and alcohol in the sudden infant death syndrome. New Zealand Cot Death Study Group

OBJECTIVES

To investigate why sharing the bed with an infant is a not consistent risk factor for the sudden infant death syndrome in ethnic subgroups in New Zealand and to see if the risk of sudden infant death associated with this practice is related to other factors, particularly maternal smoking and alcohol consumption.

DESIGN

Nationwide case-control study.

SETTING

Region of New Zealand with 78% of all births during 1987-90.

SUBJECTS

Home interviews were completed with parents of 393 (81.0% of total) infants who died from the sudden infant death syndrome in the postneonatal age group, and 1592 (88.4% of total) controls who were a representative sample of all hospital births in the study region.

RESULTS

Maternal smoking interacted with infant bed sharing on the risk of sudden infant death. Compared with infants not exposed to either risk factor, the relative risk for infants of mothers who smoked was 3.94 (95% confidence interval 2.47 to 6.27) for bed sharing in the last two weeks and 4.55 (2.63 to 7.88) for bed sharing in the last sleep, after other confounders were controlled for. The results for infants of non-smoking mothers were inconsistent with the relative risk being significantly increased for usual bed sharing in the last two weeks (1.73; 1.11 to 2.70) but not for bed sharing in the last sleep (0.98; 0.44 to 2.18). Neither maternal alcohol consumption nor the thermal resistance of the infant's clothing and bedding interacted with bed sharing to increase the risk of sudden infant death, and alcohol was not a risk factor by itself.

CONCLUSION

Infant bed sharing is associated with a significantly raised risk of the sudden infant death syndrome, particularly among infants of mothers who smoke. The interaction between maternal smoking and bed sharing suggests that a mechanism involving passive smoking, rather than the previously proposed mechanisms of overlaying and hyperthermia, increases the risk of sudden infant death from bed sharing.

Questionnaire data as predictors of urinary cotinine levels among nonsmoking adolescents

The strength of association between urinary cotinine and questionnaire data on passive smoking among 542 adolescents was evaluated. There were 103 individuals with urinary cotinine higher than 30 ng/ml; they were compared with all other subjects. The single variable that best predicted the urinary cotinine level was maternal smoking. A strong effect was made by house size and, consequently, house crowding. Maternal smoking and house crowding had a synergic effect. The subject's perception of passive smoking at home also was an independent indication of a high cotinine level. The final model had a fairly good sensitivity, whereas the specificity was somewhat lower. The results suggest that maternal smoking, house crowding, and subject's perception of a smoky environment could be surrogate indices of high passive smoking exposure in this age group and could be useful for epidemiologic studies.

Physiologic effects of maternal smoking on breast-feeding infants

Women who smoke and breast-feed pose an unknown threat to their infants' health. In this pilot study, relationships between ingestion of nicotine in breast milk and physiologic effects in the infant were investigated. Infant physiologic effects measured were temperature, pulse, respiration, systolic blood pressure, and oxygen saturation. Five smoking and five nonsmoking mother-infant pairs were studied. Breast milk was analyzed for nicotine using gas chromatography. Breast milk from smoking mothers contained a mean of 33.1 ng/mL of nicotine while the breast milk from nonsmoking mothers contained a mean of less than 6.45 ng/mL of nicotine. Infant physiologic measures were taken before and 20 min after breast-feeding. After breast-feeding, infants of smoking mothers had a significant change in respirations and oxygen saturation while infants of nonsmoking mothers had a significant change in pulse only. Results provide a scientific basis for counseling smoking, breast-feeding mothers.

Increased cerebral blood flow velocities in newborn infants of smoking mothers

Cerebral blood flow velocities (CBFV) were measured by the pulsed Doppler method in 41 infants of smoking mothers and in 59 apparently healthy control infants. Although gestational age, birth weight, and systolic blood pressure were lower in infants exposed to tobacco smoke prenatally, systolic (65 +/- 11 vs. 47 +/- 12 cm/s, mean +/- SD; P < 0.001), mean (36 +/- 6 vs. 25 +/- 6 cm/s; P < 0.001), and diastolic (17 +/- 4 vs 13 +/- 4 cm/s; P < 0.001) CBFVs in the anterior cerebral artery were significantly higher when compared to control infants. Similar differences were seen in the internal carotid and in the basilar arteries. Multiple regression analysis did not reveal differences other than maternal smoking to explain these observations. We conclude that prenatal tobacco smoke exposure is related to increased CBFVs in newborn infants. Further studies should determine whether this relation is not only statistical but causal and whether increased CBFVs are an indicator of prolonged effects of prenatal tobacco smoke exposure.

Gas chromatographic analysis of nicotine and cotinine in hair

Non-invasive validation of cigarette- or cigar-smoking behaviour is necessary for large population studies. Urine or saliva samples can be used for confirmation of recent nicotine intake by analysis of cotinine, the major metabolite of nicotine. However, this test is not suitable for validation of survey data, since the quantification of cotinine in saliva only reflects nicotine exposure during the preceding week. To validate information on tobacco use, we investigated hair samples for quantifying nicotine and cotinine by gas chromatography-mass spectrometry. Hair (about 50-100 mg) was incubated in 1 M sodium hydroxide at 100 degrees C for 10 min. After cooling, samples were extracted by diethyl ether, using ketamine as an internal standard. Drugs were separated on a 12-m BP-5 capillary column, and detected using selected-ion monitoring (m/z 84, 98 and 180 for nicotine, cotinine and ketamine, respectively). Hair from non-smokers and smokers contained nicotine and cotinine. Although it is difficult to determine an absolute cut-off concentration, more than 2 ng of nicotine per milligram of hair can be used to differentiate smokers from non-smokers. Some applications of this technique are developed to determine the status of passive smokers, the gestational exposure in babies and the pattern of an individual's nicotine use by cutting strands of hair into sections of one-month intervals.

Determinants of passive smoking in children in Edinburgh, Scotland

OBJECTIVES

Using saliva cotinine as a quantitative marker, we examined the contribution of factors other than parental smoking to children's passive exposure to tobacco smoke.

METHODS

Saliva specimens from a random sample of 734 7-year-old schoolchildren in Edinburgh, Scotland, were analyzed for cotinine. Their parents completed a questionnaire covering smoking habits and conditions in the home.

RESULTS

A number of independent predictors of cotinine were identified in addition to the main one of smoking by household members. These predictors included home ownership, social class, day of the week, season of the year, number of parents present, crowding in the home, the number of children in the household, and sex. Cotinine was higher in children from less advantaged backgrounds, during winter, on Mondays, in girls, and when fewer other children were present. The effects were similar between children from nonsmoking and smoking homes.

CONCLUSIONS

Questionnaire measures of parental smoking are insufficient to fully characterize young children's exposure to passive smoking. Because socioeconomic variables contribute to measured exposure, passive-smoking studies that treat class as a confounder and control for it may be overcontrolling.

Poluição do ar e doenças respiratórias: uma revisão

Embora saiba-se de longa data que o fumo é o principal poluente de ar lesivo às vias respiratórias, ainda não se estabeleceu o mesmo consenso a respeito dos efeitos dos demais poluentes atmosféricos sobre a saúde. Nesta revisão, buscou-se organizar as referências recentes a respeito de ação de diversos agentes poluidores sobre a saúde respiratória, tais como as partículas em suspensão, os óxidos de nitrogênio, os sulfatos e o ozônio, entre outros. A maioria dos estudos baseou-se em dados de mortalidade, sobretudo de adultos, apesar de já existirem trabalhos que investigam também os efeitos na morbidade, tanto de adultos quanto de crianças. Os primeiros estudos foram feitos em Londres e, posteriormente, em Nova York, mas atualmente inúmeros outros grupos canadenses, norte-americanos e europeus têm se debruçado sobre a questão. Tentou-se ainda rever os vários estudos nacionais a respeito do tema, de modo a fornecer um panorama geral dos conhecimentos disponíveis até o momento.

Exposure to environmental tobacco smoke in the household and urinary cotinine excretion, heavy metals retention, and lung function

The relationship between urinary levels of cotinine (U-cotinine) and arsenic (U-As), blood levels of cadmium (B-Cd), blood levels of lead (B-Pb), lung function, and questionnaire data on smoking habits were studied in 107 parents and their 46 children (7-10 y of age). There was a statistically significant relationship between the reported amount of tobacco smoked and U-cotinine levels. Nonsmokers who were married to persons who smoked had three times higher U-cotinine levels than nonsmokers whose spouses did not smoke. There was a significant association between the number of parents who smoked in the family and the U-cotinine levels of children. If only one parent smoked, maternal smoking was of greater importance than paternal smoking. There was also an association between U-cotinine and B-Cd. A study of lung function in the children revealed that vital capacity and functional residual capacity (corrected for sex, age, and height) increased as the number of parents who smoked increased. Therefore, the present study showed that (1) U-cotinine was a useful index of active smoking and environmental tobacco smoke exposure in adults and children, (2) U-cotinine was associated with the blood concentration of cadmium, and (3) environmental tobacco smoke exposure was associated with changes in lung function of children.

Relationship between urinary cotinine level and diagnosis in children admitted to hospital

The reported association between passive smoking and respiratory illness in children has been based on the parents' assessment of their own level of smoking. To more critically evaluate a causal relationship between passive smoking and childhood ill health, we used urinary cotinine, which is the major metabolite of nicotine and has a long half-life, to objectively quantitate the level of passive smoking in children. Urine was collected from 609 children (median age 3.8 yr, range 1 month to 17 yr) on admission to hospital; cotinine levels were obtained in 491 of these samples, and a comprehensive respiratory questionnaire was completed for 468 children. Statistical analysis was carried out on transformed data using both parametric and nonparametric statistics. Cotinine levels in the children correlated with the parents' current smoking (p less than 0.001). Elevated levels were found in the 41 children admitted with bronchiolitis compared with a group of a similarly aged children with nonrespiratory illnesses (p less than 0.02). Elevated levels were not found for any other diagnosis. We conclude that the urinary cotinine approach has provided objective evidence linking passive smoking to hospital admission for bronchiolitis in infants.

A time series investigation of three nicotine regulation models

Time series data were collected twice daily for 62 days from 10 individuals on three variables related to smoking habit strength: number of cigarettes smoked, salivary cotinine, and carbon monoxide. The two purposes of this study were: (a) to evaluate which time series model(s) best fits each of the measures; and (b) to determine which model of nicotine regulation is consistent with the data. Three models of nicotine regulation were considered: (a) nicotine fixed effect; (b) nicotine regulation; and (c) multiple regulation. These models provide different predictions about the size and direction of the lag-one autocorrelation. Each measure was described in terms of one of a family of time series models represented mathematically as ARIMA (p, d, q). Models varied by individual, but a single model described the majority of subjects for all three variables. The clearest model identification was for the number of cigarettes smoked where an ARIMA (1, 0, 0) model with a moderate to strong negative dependency fit the majority of the subjects. This provided strong support for the multiple regulation model. An appendix provides a brief review of time series methodology.

Environmental tobacco smoke. Medical and legal issues

Adequate information is available linking ETS to several medical problems, including respiratory illnesses in children and lung cancer in adults; nonetheless, continuing investigation is necessary to clarify several issues. Reliable information needs to be gathered on the quantity and fate of ETS chemicals in ordinary indoor environments; improved surveys quantifying passive smoke exposure should be tested along with the use of biologic markers to quantify exposure-dose relationships in nonsmokers. To date, legislation and private initiatives have been the most promising of the various measures to protect nonsmokers from ETS. While nonsmokers' judicial action has had variable success, it places the burden of challenging smoking on the nonsmoker, and it entails piecemeal, case-by-case resolution. On the other hand, legislation and private policies relieve the nonsmokers' burden to initiate the challenge, and they protect greater numbers of nonsmokers. Furthermore, legislation and policies may have a great number of direct and indirect effects. In the short term, legislation and policies that are adequately implemented and enforced alter the behavior of smokers in areas where smoking is prohibited and should result in a reduced concentration of tobacco smoke in those areas. In the long term, policies and legislation that restrict smoking in public places and the workplace help to reinforce nonsmoking as the normative behavior in society. Smoking restrictions increase public awareness and acceptance of health risks of tobacco smoke. The combination of altered social norms and reduced opportunities to smoke may encourage smokers to quit and nonsmokers, especially adolescents, not to start.

Association of poor clinical status and heavy exposure to tobacco smoke in patients with cystic fibrosis who are homozygous for the F508 deletion

We examined the association between clinical status and exposure to tobacco smoke in 44 patients homozygous for the F508 cystic fibrosis mutation. Heavy exposure to tobacco smoke was significantly associated with lower Shwachman scores, poorer results of pulmonary function tests, and a fivefold increase in the number of pulmonary-related hospitalizations during the previous year.

Passive smoking among children with chronic respiratory disease

The purpose of this study was to determine the prevalence and source of passive smoke exposure among children with chronic respiratory diseases and compare these to both a well child and nonrespiratory chronic illness child population. Rates and source of passive smoke exposure were compared among four child groups: asthma, cystic fibrosis, rheumatoid arthritis, and well children using a questionnaire mailed to the parents of the selected children. Twenty percent of respondents reported current smoking with a significantly higher rate among the cystic fibrosis and rheumatoid arthritis groups. One-third of all children surveyed were exposed to passive smoke at home and/or day care on a daily basis. Over 80% of the asthma and cystic fibrosis respondents reported a change in smoking behavior (i.e., smoking outside the home or smoking fewer cigarettes) after the diagnosis of their child's illness as compared with only 40% of the nonrespiratory groups. Health care providers need to inquire about potential sources of passive smoke exposure in their patients, particularly children with chronic respiratory disease.

Stability of salivary cotinine sent through the U.S. mail for verification of smoking status

Until now mass media smoking cessation studies have relied almost exclusively on self-reports of smoking cessation because biochemical confirmation has not seemed practical. This study investigated the reliability of mailed salivary cotinine specimens for the determination of smoking status. Two simultaneous saliva specimens were obtained from 10 smokers and 10 nonsmokers. One of each pair was frozen immediately. The other was sent through the local U.S. mail and then subjected to additional physical agitation and heat before being frozen. All specimens were subsequently analyzed for cotinine. No cotinine was detectable in any of the nonsmokers' specimens. There was excellent correlation between the paired smokers' specimens. These results show that the mailing of saliva specimens for cotinine analysis is practical and provides accurate data on smoking status. It is an approach which could easily be used in mass media smoking cessation studies to biochemically confirm smoking behavior.

Passive smoking and childhood asthma. Urinary cotinine levels in children with asthma and in referents

Passive exposure to tobacco smoke was assessed in children with asthma (age 3-15) and in referents. There was statistically significantly (P less than 0.0005) higher excretion of the nicotine metabolite, cotinine, in the urine of 49 children with asthma (geometric mean 10 ng/ml) compared with 77 referents (4.8 ng/ml). Maternal smoking was statistically significantly more prevalent among the asthmatics than among the referents (relative risk = RR = 2.6, 95% C1 = 1.2-5.3). In conclusion, the exposure to environmental tobacco smoke in asthmatic children was higher than among healthy children, indicating that passive smoking may be a predisposing and/or aggravating factor for childhood asthma.

Upper respiratory tract environmental tobacco smoke sensitivity

Some patients report rhinitis symptoms after exposure to environmental tobacco smoke (ETS), but objective assessments of this response have been lacking. Furthermore, the mechanism of this response is unknown. We assessed the frequency of ETS-related symptoms by administering a questionnaire to 77 healthy nonsmoking young adults who were participating in an unrelated study. Of the subjects 34% (26 of 77) reported one or more rhinitis symptoms (congestion, rhinorrhea, or sneezing) following ETS exposure. We then exposed 10 historically ETS-sensitive (ETS-S) and 11 historically ETS-nonsensitive (ETS-NS) subjects to 15 min of clean air followed by 15 min of sidestream tobacco smoke (CO concentration of 45 parts per million). At selected time points during these procedures we recorded symptoms, posterior nasal resistance, and spirometry and performed nasal lavages. ETS-S but not ETS-NS subjects reported significant (p less than 0.01) increases in nasal congestion, headache, chest discomfort or tightness, and cough following exposure to sidestream tobacco smoke. Rhinorrhea symptoms were greater and more prolonged in ETS-S subjects compared to ETS-NS subjects. Significant (p less than 0.01) increases in perception of odor and in eye, nose, and throat irritation occurred in both study groups, but ETS-S subjects reported significantly more nose and throat irritation. No significant changes in posterior nasal resistance occurred in the ETS-NS group but a significant increase occurred in the ETS-S subjects, with the resistance rising from 3.8 +/- 0.5 cm H2O/L/s (mean +/- SE) preexposure to a peak of 8.0 +/- 2.7 cm H2O/L/s 20 min after completion of the smoke exposure (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Highly sensitive immuno-assays for the determination of cotinine in serum and saliva. Comparison between RIA and an avidin-biotin ELISA

Two immuno-assay methods (RIA and ELISA) have been developed for the accurate and sensitive measurement of cotinine in human body fluids (serum, saliva). RIA uses [3H]cotinine as antigen and charcoal/dextran for separating cotinine-bound antibodies from the free derivative. Another technique (ELISA) was developed to avoid the use of radio-labelled compounds and to determine cotinine in large populations, including passive or non-smokers who usually present very low concentrations. The two techniques were analytically validated. The detection limit was similar (0.1 micrograms/l) and the precision was better than 10% for both techniques. Non-smoker values ranged from 0.1 to 17 micrograms/l by ELISA and 0.1 to 27.5 micrograms/l by RIA, whereas smoker values ranged from 50 to 1000 micrograms/l (ELISA) and from 70 to 800 micrograms/l (RIA). The comparative analysis of cotinine in 96 human sera revealed a good correlation between the two methods (r = 0.97) and a reliable discrimination between the populations of non-smokers and smokers. As usual, the ELISA is more rapid (4 h 30 min) than the RIA (longer than 48 h). ELISA is proposed for use in the epidemiological investigation of the human tobacco risk.

Smoking characteristics and inhalation biochemistry in the Scottish population

Data from a cross-sectional random population sample of 10,359 middle-aged Scottish men and women are used to investigate the relationships between self-reported tobacco consumption and three biochemical markers of tobacco inhalation: expired air carbon monoxide (CO), serum thiocyanate and serum cotinine. These data represent one of the largest samples of these biochemical markers yet analysed. The results show that, for each sex, the biochemical markers are highly correlated for smokers and for the entire sample of mixed smokers and non-smokers. CO is the preferred biochemical marker, in such groups, because it is the cheapest, is non-invasive and gives virtually instantaneous results. Self-reported daily cigarette consumption also correlates well with each of these biochemical markers, and so it appears that people are, in the context of population studies, mainly truthful about their smoking. The relationships with self-reported cigarette consumption are curvilinear with apparent levelling out of the gradient at around 25 cigarettes/day for cotinine and thiocyanate and at greater than 40 cigarettes/day for CO. Sex differences are small, although thiocyanate is generally higher and cotinine generally lower in women with the same self-reported cigarette consumption as men. Amongst non-smokers, only cotinine is able to discriminate between self-reported levels of exposure to passive smoking. CO and thiocyanate are not suitable for measuring low levels of smoke inhalation, such as found in passive smokers.

Acute effect of passive smoking on lung function and airway responsiveness in asthmatic children

The effect of a 1-hour exposure at rest during passive cigarette smoking (20 ppm CO) or Sham was investigated in 11 children with bronchial asthma (age range, 8-13 yr; ten boys, one girl). Nine of the subjects were on regular therapy with inhaled beta 2-agonists and disodium cromoglycate. Both drugs were withheld at least 6 hours prior to each study session. Exposure was performed in an environmental chamber. Before and immediately after exposure, lung function and symptom scores were determined. After exposure, a histamine inhalation challenge was performed to determine the concentrations that caused a 100% increase in SRaw (PC100SRaw) and a 20% fall in FEV1, (PC20FEV1). Mean (SD) SRaw before and after Sham was 8.7 (3.6) and 9.0 (3.2) cmH2O.s, and mean FEV1 (SD) was 1.97 (0.32) and 1.98 (0.40) L, respectively. Before and after cigarette smoking, mean SRaw (SD) was 10.4 (5.3) and 9.4 (3.3) cmH2O.s, and mean FEV1 (SD) was 1.95 (0.37) and 1.94 (0.35 L, respectively. Geometric mean (SD) PC100 SRaw and PC20FEV1 after Sham was 1.39 (3.0) and 0.70 (2.7) mg/mL, and after passive smoking 1.65 (2.5) and 0.96 (2.3) mg/mL, respectively. There were no statistical differences in lung function and PC values between Sham and passive cigarette smoking. The main symptoms during passive smoking were irritation of the eye and the nasopharynx. Our observations suggest that in children with mild bronchial asthma 1 hour of passive cigarette smoking does not cause consistent changes of lung function and bronchial responsiveness.

Environmental tobacco smoke exposure during infancy

We collected information about household smoking habits from 518 mothers when they made their first well child visit with a 6 to 8-week old infant. A urine sample was also collected from the infant, the cotinine concentration measured, and the measurement correlated with data provided by the mother. Eight percent of the infant urine cotinine values fell at or above 10 micrograms/L in the 305 households where no smoking was reported. Corresponding rates were 44 percent in the 96 households where a member other than the mother smoked, 91 percent in the 43 households where only the mother smoked, and 96 percent in the 74 households where both the mother and another household member smoked. In households where the mother smoked, infant urine cotinine levels were lower in the summer, and higher when the infant was breast-fed. A screening question about family smoking habits in conjunction with well child care could effectively define a group of infants exposed to environmental tobacco smoke and thus be at greater risk for respiratory diseases.

Exposure of children with cystic fibrosis to environmental tobacco smoke

BACKGROUND

In children, passive exposure to environmental tobacco smoke has been associated with growth suppression and an increased frequency of respiratory tract infections. On the assumption that this association would be more pronounced in children with chronic pulmonary disease, we examined the growth, nutritional status, lung function, and clinical condition of children with cystic fibrosis in relation to their exposure to environmental tobacco smoke.

METHODS

We studied 43 children (age, 6 to 11 years) on entry to a summer camp and then again after two weeks in this smoke-free environment. Twenty-four of the children (56 percent) came from homes with smokers.

RESULTS

There appeared to be a dose-dependent relation between the estimate of smoke exposure (cigarettes smoked per day in the home) and overall severity of disease, as assessed by the age-adjusted rate of hospital admissions (r = 0.58), peak expiratory flow rate (r = -0.39), and measures of growth and nutrition, including weight percentile (r = -0.37), height percentile (r = -0.44), midarm circumference (r = -0.42), and triceps skin-fold thickness (r = -0.31). These effects were most evident in the girls. When only the 24 children from homes with smokers were analyzed, however, the dose-dependent relation was present only for the number of hospital admissions and for height. Among the children with good lung function (n = 21) or with normal weight for height (n = 27) at the start of camp, those who had been exposed to tobacco smoke gained significantly more weight during the two weeks of camp than did the children from smoke-free homes.

CONCLUSIONS

These data suggest that passive exposure to tobacco smoke adversely affects the growth and health of children with cystic fibrosis, although the possibility cannot be ruled out that social, economic, or other factors determined both the smoking status of the household and the nutritional status of the children.

Cotinine concentrations in amniotic fluid and urine of smoking, passive smoking and non-smoking pregnant women at term and in the urine of their neonates on 1st day of life

Cotinine was measured in the amniotic fluid and urine of 31 pregnant women and in the urine of their offspring. Amniotic fluid cotinine was 8 times higher in active and 2.5 times higher in passive smokers than in non-smokers. In general, amniotic fluid cotinine was considerably higher than urinary cotinine both in active and in passive smokers. Estimation of cotinine both in amniotic fluid immediately before delivery and in urine of the newborn on the 1st day of life aids in assessing the degree of prenatal exposure to tobacco smoke.

A review of the use of saliva cotinine as a marker of tobacco smoke exposure

Cotinine, the major metabolite of nicotine, is a useful marker of exposure to tobacco smoke. It can be measured in plasma, urine, or saliva. However, distinguishing between active and passive smoking on the basis of a cotinine measurement may be difficult. In order to evaluate the relationship between saliva cotinine concentration and self-reported tobacco smoke exposure in both active and passive smokers, an English-language literature search using MEDLINE was conducted (1973-1989), and the bibliographies of identified articles were reviewed. Of 43 originally identified articles, only 22 met the criteria for inclusion. Specific information regarding population studied, reported tobacco smoke exposure, method of measurement, and cotinine concentrations was assessed. Passive smokers usually have cotinine concentrations in saliva below 5 ng/ml, but heavy passive exposure can result in levels greater than or equal to 10 ng/ml. Levels between 10 and 100 ng/ml may result from infrequent active smoking or regular active smoking with low nicotine intake. Levels greater than 100 ng/ml are probably the result of regular active smoking. Four categorizations of tobacco smoke exposure are suggested on the basis of saliva cotinine concentrations.

Lipoprotein and oxygen transport alterations in passive smoking preadolescent children. The MCV Twin Study

We investigated the cardiovascular effects of lifelong passive cigarette smoke exposure in preadolescent children and examined the following questions: 1) Is systemic oxygen transport altered? 2) Are coronary heart disease risk factors adversely affected? We recruited 216 families from the MCV Twin Study; 105 had at least one smoking parent. Serum thiocyanate and cotinine levels were used as measures of smoke exposure in the children and thiocyanate was proportional to the number of parental cigarettes smoked each day (p = 0.0001). Paternal smoking had no effect on these measures. Whole blood 2,3-diphosphoglycerate was higher in smoke-exposed than unexposed children (p less than 0.01) and was related to the thiocyanate level (p less than 0.02). High density lipoprotein (HDL) cholesterol was lower in passive smoking children (p less than 0.05); the HDL2 subfraction was reduced in passive smoking boys, while the HDL3 subfraction was reduced in passive smoking girls. Significant adverse alterations in systemic oxygen transport and lipoprotein profiles are already present in preadolescent children exposed to long-term passive cigarette smoke, primarily from maternal smoke. Children with long-term exposure to passive smoke may be at elevated risk for the development of premature coronary heart disease.

Smoking history, instructions and the effects of nicotine: two pilot studies

In Study 1, ten never-smokers, ten ex-smokers and nine current smokers received nicotine (2 mg) and placebo gum hourly for 4 hours on 2 consecutive days in a randomized, double-blind, cross-over protocol. Dysphoria from nicotine was greatest in never-smokers, intermediate in ex-smokers, and least in current smokers (p less than 0.05). On the third day, subjects were given concurrent access to the same gums and told to chew ad lib. Across all subjects, nicotine was an aversive stimulus (i.e., self-administered less than placebo). Nicotine was avoided most in never-smokers, intermediate in ex-smokers and least in current smokers (p less than 0.05). Study 2 used a similar protocol and compared the nine current smokers in Study 1 who were not told they would receive nicotine with eight informed smokers, i.e., smokers told they would receive nicotine. Although nicotine appeared to be a reinforcer more often in the informed smokers than in the uniformed smokers (63% vs. 22%), this result was not statistically significant. Our results suggest 1) past drug history can influence the stimulus effects of nicotine and 2) the effects of instructions on the response to nicotine may be less in experimental settings than in therapeutic settings.

Home air nicotine levels and urinary cotinine excretion in preschool children

We examined the extent of correlation between home air nicotine levels and urine cotinine/creatinine ratios (CCR) in 27 children who attended a research day care program where they were not exposed to environmental tobacco smoke (ETS) during the daytime hours. Average concentrations of nicotine in home air were determined by active air sampling during the evening and night hours on 2 consecutive days. Urine samples for cotinine and creatinine determinations were collected before, during, and after the two sampling periods. In addition, four sequential weekly urine samples for CCR were obtained from study children to determine the extent to which single determinations of CCR were representative for individual children. Fifteen children resided in homes with smokers, and 12 did not. Urine CCR consistently distinguished most exposed and unexposed children. However, three exposed children had urine CCRs that clustered routinely around the criterion CCR (30 ng/mg cotinine-creatinine) that best distinguished exposed and unexposed children. In children exposed to ETS in the home, there was a significant correlation between average home air nicotine levels and the average logarithm of urine CCR the two mornings after the home air monitoring periods (r = 0.68; p = 0.006). In study children, urine CCRs were remarkably stable over the 1-month observation period. Rank correlation coefficients for sequential weekly determinations of CCR were consistently greater than r = 0.88; p less than 0.0001.