Passive smoking during the first year of life

The Effects of Maternal Smoking on Pregnancy and Offspring: Possible Role for EGF?

Cigarette smoke exposure during pregnancy and lactation is associated with adverse pregnancy outcomes. Here, we investigated the effects of maternal smoke exposure on pregnancy and offspring immunity and explored whether, epidermal growth factor (EGF), an important growth-promoting factor in human colostrum and milk, might be a possible missing link in maternal smoke exposure and changes in infants’ immune responses. Pregnant BALB/c mice were exposed to either cigarette smoke or air during gestation and lactation, and effects on pulmonary inflammation in dams and immune responses in offspring were examined. Maternal smoke exposure increased airway hyperresponsiveness and accumulation of inflammatory cells in the lungs of pregnant dams compared to non-pregnant dams. The E-cadherin protein expression was reduced in mammary glands of cigarette smoke-exposed pregnant dams. EGF levels were higher in mammary glands and serum of smoke-exposed pregnant dams compared to air-exposed pregnant dams. Offspring from cigarette smoke-exposed dams exhibited elevated levels of IL-17A, MCP-1, IL-22, and IL-13 in anti-CD3 stimulated spleen cell culture supernatants. EGF levels were also increased in serum of offspring from smoke-exposed dams. A positive correlation was observed between serum EGF levels and neutrophil numbers in bronchoalveolar lavage fluid of the dams. Interestingly, IL-17A, MCP-1, IL-22, IL13, and IFN-γ levels in anti-CD3 stimulated spleen cell culture supernatants of male pups also showed a positive correlation with EGF serum levels. In summary, our results reveal that maternal smoke exposure predisposes dams to exacerbated airway inflammation and offspring to exacerbated immune responses and both phenomena are associated with elevated EGF concentrations.

Long-term cardiovascular reprogramming by short-term perinatal exposure to nicotine's main metabolite cotinine

AIM

Gather 'proof-of-concept' evidence of the adverse developmental potential of cotinine (a seemingly benign biomarker of recent nicotine/tobacco smoke exposure).

METHODS

Pregnant C57 mice drank nicotine- or cotinine-laced water for 6 wks from conception (N_PRE = 2% saccharin + 100 μg nicotine/mL; C_PRE = 2% saccharin + 10 μg cotinine/mL) or 3 wks after birth (C_POST = 2% saccharin + 30 μg cotinine/mL). Controls drank 2% saccharin (CTRL). At 17 ± 1 weeks (male pups; CTRL n = 6; C_POST n = 6; C_PRE n = 8; N_PRE n = 9), we assessed (i) cardiovascular control during sleep; (ii) arterial reactivity ex vivo; and (iii) expression of genes involved in arterial constriction/dilation.

RESULTS

Blood cotinine levels recapitulated those of passive smoker mothers' infants. Pups exposed to cotinine exhibited (i) mild bradycardia - hypotension at rest (p < 0.001); (ii) attenuated (C_PRE , p < 0.0001) or reverse (C_POST ; p < 0.0001) BP stress reactivity; (iii) adrenergic hypocontractility (p < 0.0003), low protein kinase C (p < 0.001) and elevated adrenergic receptor mRNA (p < 0.05; all drug-treated arteries); and (iv) endothelial dysfunction (N_PRE only).

CONCLUSION

Cotinine has subtle, enduring developmental consequences. Some cardiovascular effects of nicotine can plausibly arise via conversion into cotinine. Low-level exposure to this metabolite may pose unrecognised perinatal risks. Adults must avoid inadvertently exposing a foetus or infant to cotinine as well as nicotine.

Physiological effects of infant exposure to environmental tobacco smoke: a passive observation study

This study explored infant physiologic responses of exposure to environmental tobacco smoke (ETS) using a longitudinal passive observation study with a control group. Fifteen smoking and 15 non-smoking mothers were initially contacted in hospital maternity units, with home visits made when their infants were 2, 4, and 6 weeks old. Exposure to ETS was measured using infant urinary nicotine and cotinine levels. The physiologic effects of infant ETS exposure were measured by rectal temperature, pulse rate, respiratory rate, blood pressure, and oxygen saturation. The smoking mothers in this sample were poorer, had less education, and were less likely to be married than the mothers who did not smoke. At birth, the infants of smoking mothers had higher diastolic blood pressure than infants of non-smoking mothers (p < .008). Mothers who smoke cigarettes should be educated that maternal smoking behavior can affect an infant's cardiovascular function. Parents should also be counseled about the risks of smoking in close proximity and/or in an enclosed space with an infant, especially in a motor vehicle.

The association between prenatal exposure to cigarettes and cortisol reactivity and regulation in 7-month-old infants

We examined the association between prenatal exposure to cigarettes and adrenocortical responses to stress in 7-month-old infants. Cortisol levels were assessed twice prior to and twice following affect-eliciting procedures in 111 (59 exposed and 52 nonexposed) infants. Cortisol reactivity was defined as the difference between the peak poststressor cortisol level and the pretask cortisol level. Higher values indicated higher cortisol reactivity. Exposed infants had higher peak cortisol reactivity than nonexposed infants. There were no differences in pretask cortisol levels. Maternal hostility mediated the association between cigarette exposure and peak cortisol reactivity. Furthermore, infant gender moderated this association such that exposed boys had significantly higher peak cortisol reactivity than nonexposed infants or exposed girls. These findings provide additional evidence that prenatal cigarette exposure is associated with dysregulation during infancy and that early adverse, nonsocial experiences may have relatively long-lasting effects on cortisol reactivity in infants.

Exposure to environmental tobacco smoke among infants in southern Thailand: a study of urinary cotinine

We performed a survey to assess the exposure to environmental tobacco smoke (ETS) in 1-year-old infants in Thailand. Of the 725 infants, it was reported that 73.3% had household smoking and 40.7% had detectable urinary cotinine. Twenty-five infants (3.4%) had urinary cotinine in the range of adult heavy smokers. The prevalence of ETS exposure was significantly higher in infants with a father whose education was < or = grade 6 than in those with father's education >6 years (44.0% vs. 36.0%, p = 0.039). Data on the exposure to ETS among infants will provide prevalence information and identify population subgroups at increased risk for exposure.

The association between prenatal exposure to cigarettes and infant and maternal negative affect

This study examined the association between prenatal exposure to cigarettes and infant and maternal negative affect. Participants were 115 mother-infant dyads (69 prenatally exposed to cigarettes and 46 nonexposed). Infant and maternal negative affect were both assessed during the neonatal period (2-4 weeks of age) and again at 7 months of infant age. Results indicated that only prenatal exposure to cigarettes predicted infant negative affect. Infants who were prenatally exposed to more cigarettes had higher levels of negative affect at both time points. Furthermore, regression analyses indicated that both infant and maternal negative affect during the neonatal period predicted maternal negative affect at 7 months of age. These results highlight the importance of considering the reciprocal relationship between infant and maternal behavior when examining developmental outcomes among infants prenatally exposed to cigarettes.

Smoking hygiene: reducing infant exposure to tobacco

The American Academy of Pediatrics recently removed nicotine from the list of drugs contraindicated during breastfeeding. The objective of this study was to evaluate the feasibility of determining the effect of a smoking hygiene intervention on infants of breastfeeding mothers who smoke cigarettes. An experimental design with repeated measures was used. A convenience sample of 35 mother-infant dyads from seven sites was recruited and randomly assigned to the intervention or control group. Of the 27 dyads completing the study, 16 were in the experimental group and 11 were in the control group. Smoking hygiene was introduced when infants were 2 weeks old and reinforced when they were 3 and 5 weeks old. At these three data points, infant health and urinary nicotine and cotinine levels were measured, as well as the mothers' breast-milk nicotine and cotinine levels and smoking hygiene behaviors. Recruiting and retaining a sample of breastfeeding mothers who smoke proved difficult. Only 27% of women in the intervention group implemented all aspects of the smoking hygiene intervention behaviors. Repeated-measures ANOVA revealed no difference in a) infant urinary nicotine and cotinine levels or b) breast-milk nicotine and cotinine levels between the two groups. The McNemar test for related samples revealed no difference between frequency of respiratory symptoms in either the control or intervention groups when Week 2 levels were compared with levels at Weeks 3 and 5. Mothers were not successful in adhering to the smoking hygiene intervention. To adequately test interventions, strategies must be developed to help women incorporate health-promoting behaviors into their lives.

The association between maternal smoking and secondhand exposure and autonomic functioning at 2-4 weeks of age

This study examined the association between maternal smoking and exposure to environmental tobacco smoke (ETS) during pregnancy and infant heart rate. Participants were 62 mother-infant dyads where mother smoked during pregnancy, 47 dyads where mother did not smoke during pregnancy but was exposed to ETS and 47 dyads where mother did not smoke and was not exposed to ETS. Average heart rate (HR) and respiratory sinus arrhythmia (RSA) were assessed at 2-4 weeks of age during sleep. Infants in both exposure groups had higher HR and lower RSA than nonexposed infants. Furthermore, boys in both exposure groups had higher HR and lower RSA than girls. These results highlight the importance of considering prenatal ETS exposure and infant gender when assessing infant outcomes.

Addressing tobacco smoke exposure: passive and active

Many smoking parents are receptive to receiving smoking counseling messages and pediatric health care providers need to increase their efforts to address ETS exposure. Efforts to prevent smoking acquisition should continue by parents, doctors, schools, and the community. Start early in childhood to promote positive family communication and role modeling. Screen for tobacco use or intention and provide counseling to teen without the parent in room. Brief tobacco-dependence interventions are effective. Every patient/parent that uses tobacco should be identified, urged to quit, and offered treatment. Those willing to quit should be provided effective treatments using the "5 A's". Those unwilling to quit should be motivated using "5 R's". Quitting smoking is a major challenge but it is one that many people successfully achieve every day. Even a small increase in smoking cessation can be significant impact from a public health perspective and pediatric providers can play a significant role.

Estimation of the impact on children's health of environmental tobacco smoke in England and Wales

In this paper, the population attributable risk (PAR), a measure of the excess risk of disease associated with a risk factor, is calculated for some of the common adverse health effects that have been associated with exposure of children to environmental tobacco smoke (ETS): childhood lower respiratory illness, chronic middle ear disease, asthma and sudden infant death syndrome (SIDS). Published data on both risk estimates and the percentage of children exposed to ETS in the home (prevalence of ETS) have been utilised. The percentage of childhood lower respiratory illness and middle ear disease typically attributable to ETS from either parent smoking ranged from 9% for asthma prevalence and for referral for glue ear, to 25% for hospital admission for lower respiratory illness. Where data were available to calculate PARs separately for mother only smoking and father only smoking, the PARs were generally larger for mothers only smoking, due mainly to higher odds ratios for mothers only smoking. The PAR for SIDS attributable to ETS from mother only smoking was 11%. Although based on a small number of studies, the PAR for SIDS attributable to smoking of fathers only was similar to that attributable to the smoking of mothers only, largely due to the higher prevalence of households where only the father smokes. This study has shown that the impact of ETS on childhood illness can be considerable, emphasising the importance of the need to develop effective strategies for reducing the risk of ETS exposure in the home and elsewhere.

A smoking cessation intervention for parents of children who are hospitalized for respiratory illness: the stop tobacco outreach program

OBJECTIVE

Parental smoking is associated with increased rates and severity of childhood respiratory illness. No previous studies have examined child hospitalization as an opportunity for parental smoking cessation. We evaluated the feasibility of implementing a smoking cessation intervention for parents at the time of child hospitalization for respiratory illness.

METHODS

We performed a prospective cohort study of smoking parents who had a child who was admitted to an academic children's hospital for a respiratory illness between January and April 2000. All enrollees were offered the Stop Tobacco Outreach Program, which includes an initial motivational interview, written materials, nicotine replacement therapy (NRT), telephone counseling, and fax referral to parents' primary clinician. The primary outcome was completion of all 3 counseling sessions. Two-month follow-up outcomes were quit attempts, cessation, NRT use, primary care visits, household smoking prohibition, and satisfaction.

RESULTS

A total of 126 smoking parents met eligibility criteria, and 71 (56%) enrolled in the study. Of the 71, 80% completed all counseling sessions and 56% accepted free NRT at the time of enrollment. At the 2-month follow-up, of the 71 initial enrollees, 49% reported having made a quit attempt that lasted at least 24 hours, 21% reported not smoking a cigarette in the last 7 days, 27% reported having used NRT, and 38% had had a visit with their own primary clinician. The proportion of parents who reported rules prohibiting smoking in the house increased (29% vs 71%). Parental rating of the overall usefulness of the program was 4.3 +/- 0.9 (1 standard deviation) on the 5-point scale 1 = not at all and 5 = a great extent.

CONCLUSIONS

This study demonstrates the feasibility of engaging parents in smoking cessation interventions at the time of child hospitalization for respiratory illness. Previous work done in a similar sample of parental smokers has shown extremely low ever-use rates of cessation programs. High rates of acceptance of in-hospital and telephone counseling in this study support the notion of child hospitalization as a teachable moment to address parental smoking.

Environmental tobacco smoke exposure and nocturnal symptoms among inner-city children with asthma

BACKGROUND

Environmental tobacco smoke (ETS) is a frequent exposure and is linked to asthma among inner-city children.

OBJECTIVE

We sought to examine the relationship among ETS exposure, select asthma symptoms, and consequences among inner-city children with asthma.

METHODS

Data from interviews with primary caregivers of inner-city elementary school children with asthma were evaluated (n = 590). Caregiver reports of child asthma symptoms, exercise limitations, asthma management, health care use, and ETS exposure were examined.

RESULTS

Smoking in the home was reported by 29.4% of primary caregivers. ETS exposure (yes/no) was not related to frequency of child nocturnal symptoms or other select asthma morbidity markers. However, among children exposed to ETS, the frequency and severity of child nocturnal symptoms were highest among children exposed to moderate-to-heavy levels of ETS. After controlling for child age, anti-inflammatory medication use, asthma primary care, and caregiver's education, exposure to higher levels of ETS was associated with nearly a 3-fold increase in nocturnal symptoms in children (odds ratio, 2.83; 95% CI, 1.22-6.55).

CONCLUSION

Among elementary school inner-city children with asthma, exposure to higher levels of ETS was associated with increased frequency of nocturnal symptoms. Reducing the exposure of children with asthma to ETS should be a clear priority in developing effective asthma management plans for inner-city families.

A randomized trial to reduce passive smoke exposure in low-income households with young children

OBJECTIVE

Passive smoke exposure among children is widespread in the United States; estimates suggest that almost 40% of children who are younger than 5 years live with a smoker. Few randomized studies of passive smoke exposure reduction among children have been conducted, and the impact of interventions that have been evaluated has been limited. The objective of this study was to determine whether a motivational intervention for smoking parents of young children will lead to reduced household passive smoke exposure.

METHODS

Project KISS (Keeping Infants Safe From Smoke), a theory-driven exposure reduction intervention targeting low-income families with young children, was a randomized controlled study in which participants-smoking parents/caregivers (N = 291) who had children who were younger than 3 years and who were recruited through primary care settings-were randomly assigned to either the motivational intervention (MI) or a self-help (SH) comparison condition was used. Follow-up assessments were conducted at 3 and 6 months. The MI condition consisted of a 30- to 45-minute motivational interviewing session at the participant's home with a trained health educator and 4 follow-up telephone counseling calls. Feedback from baseline household air nicotine assessments and assessment of the participant's carbon monoxide level was provided as part of the intervention. Participants in the SH group received a copy of the smoking cessation manual, the passive smoke reduction tip sheet, and the resource guide in the mail. Household nicotine levels were measured by a passive diffusion monitor.

RESULTS

The 6-month nicotine levels were significantly lower in MI households. Repeated measures analysis of variance across baseline, 3-month, and 6-month time points showed a significant time-by-treatment interaction, whereby nicotine levels for the MI group decreased significantly and nicotine levels for the SH group increased but were not significantly different from baseline.

CONCLUSIONS

This study targeted a large sample of racially and ethnically diverse low-income families, in whom both exposure and disease burden is likely to be significant. This is the first study to our knowledge that has been effective in reducing objective measures of passive smoke exposure in households with healthy children. These findings have important implications for pediatric health care providers, who play an important role in working with parents to protect children's health. Providers can help parents work toward reducing household passive smoke exposure using motivational strategies and providing a menu of approaches regardless of whether the parents are ready to quit.

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

IMPLICATIONS

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

Intervention and policy issues related to children's exposure to environmental tobacco smoke

BACKGROUND

Children's exposure to environmental tobacco smoke (ETS) is unacceptably high; almost 40% of children in the United States are regularly exposed to ETS.

METHODS

This paper presents a review of the literature that evaluates interventions designed to reduce ETS exposure among young children. In addition, it presents the study design for Project KISS (Keeping Infants Safe from Smoke), an intervention designed to utilize exposure-related feedback to increase parents' motivation for ETS reduction and to reduce household ETS levels. Baseline data are presented to illustrate factors that should be addressed in ETS interventions.

RESULTS

The literature review demonstrates the dearth of studies in the literature targeting ETS reduction among children. Participants in Project KISS believed that smoking had affected their children's health and were in later stages of motivational readiness to quit smoking than is typically observed. However, they face a number of challenges to smoking, such as high prevalence of nicotine dependence, high prevalence of living with other smokers, and socioeconomic and stress-related barriers.

CONCLUSIONS

The policy implications of this research are discussed, and recommendations are made for future research.

Measuring secondhand smoke exposure in babies: the reliability and validity of mother reports in a sample of low-income families

The reliability and validity of mother's reports of their infants' exposure to secondhand smoke (SHS) were examined in an ethnically diverse sample of low-income, low-education families (N = 141 mothers). At baseline and posttest, smoking mothers reported about their infants' SHS exposure at different locations and by different sources during the previous week. Findings show that mothers can give reliable accounts of the degree to which they contribute to their babies' SHS exposure. Mothers are able to differentiate between their own smoking behavior and the extent to which they expose their infants. Consistent with the overall exposure pattern, exposure caused by the mother and exposure occurring at home showed the strongest associations with biological and environmental measures. These findings suggest that smoking mothers can provide reliable and valid reports of the degree to which their infants are exposed to SHS.

Environmental tobacco smoke exposure in children: household and community determinants

To determine the most important sources of environmental tobacco smoke exposure to young children, the authors studied the associations among urinary cotinine, reported household smoking habits, and socioeconomic variables in 575 schoolchildren aged 6-11 y. The school children were among a population of prodigious smokers in Cape Town, South Africa. Eighty percent of the children were exposed to environmental tobacco smoke. Maternal smoking, which was adjusted for creatinine, accounted for 21.8% of the variation in urinary cotinine--more than all other sources combined. The male parent and other household smokers accounted for 12.7% of the variation, and socioeconomic indicators explained an additional 4.8%. By defining the ecological variable of smoking prevalence per school, the authors estimated a "community" contribution of 3.3%. The relative importance of different sources of smoke should be taken into account in the prevention of environmental tobacco smoke exposure in young children. Most importantly, of all the sources of environmental tobacco smoke, mothers' smoking habits had the greatest impact on exposure to children.

Measuring infant exposure to environmental tobacco smoke

Methods to measure infant exposure to environmental tobacco smoke (ETS) are needed to identify infants at highest risk for ETS-related health problems. The purpose of this study was to validate measures sensitive to changes in levels of infant exposure to ETS and to develop a predictive model of infant exposure to ETS. Fifteen infants of smoking mothers were followed from birth to 6 weeks of age. Exposure to ETS was measured by using a smoking habits questionnaire, cigarette "butt" collection, infant urine nicotine and cotinine levels, and ambient nicotine (personal air monitors). The 24-hour cigarette butt collection was the best predictor of acute (adjusted r2 = .83) and chronic exposure (adjusted r2 = .47) measured by infant urinary nicotine and cotinine levels when the infants were 2 weeks of age. Including scores on the smoking habits questionnaire and ambient nicotine levels increased the adjusted r2 to .88 and .61, respectively.

Passive smoking exposure of sick children in Hong Kong

1. This study aims to investigate the extent of passive smoking exposure of sick children in Hong Kong; their father's smoking behaviors and their mother's action to protect the child from environmental tobacco smoke (ETS). 2. This cross-sectional survey was the first phase of a randomized controlled trial on a health education intervention provided by nurses in the general paediatric wards of four major hospitals in Hong Kong. The subjects are non-smoking mothers of sick children admitted to hospital and with a smoking husband living together in the same household with the child. Eligible subjects completed a self-administered baseline questionnaire before entering into the trial. 3. All the 848 children whose mothers completed the questionnaire during December 1997 to April 1998 had a smoking father. They constituted about 24% (95% CI: 22.6-24.9%) of all the sick children during the same period. More than half of the children's fathers (55%; 51.6-58.3%) smoked 1-14 cigarettes per day and about 68% (64.7-71.0%) of them were daily smokers for over 10 years. Over half (53%; 49.4-56.2%) of the fathers smoked 1-14 cigarettes at home every day. About 21% of the fathers smoked near the child occasionally and 31% (27.4-33.6%) smoked 1-14 cigarettes near the child per day. About 16% of the children lived with more than one smoker (2-3). About 86% (83.3-88.0%) of the children had 1-3 smokers who smoked at home and 61% (58.1 - 64.7%) of them had 1-3 smokers who smoked near them every day. However, 70% of the children were reported by their mothers as exposed to ETS at home. This percentage (70%) was less than the percentage (86%) of smokers who smoked at home daily. About 31.1% of the mothers reported symptoms of coughing and running nose (20.6%) in their children when they were exposed to ETS. To protect the child from ETS exposure, 43% of the mothers requested the father not to smoke near the child, 33.1% requested the father to smoke less cigarettes and 31.5% advised the father to quit smoking. 4. In conclusion, sick children in Hong Kong are at risk of exposure to ETS, but not all mothers are aware of the health risks and their actions were inadequate. There is a critical need to promote awareness of ETS exposure and the health risks in the family in Hong Kong so as to reduce illness and hospital admission in children.

From in utero and childhood exposure to parental smoking to childhood cancer: a possible link and the need for action

The objective of the present work is to critically summarize published studies and reassess the state of knowledge on a highly controversial topic: the potential association between prenatal exposure to passive smoking as well as maternal active smoking and postnatal exposure to environmental tobacco smoke (ETS) and enhanced incidence of childhood cancer. Elements to be considered include the substantial proportion of pregnant women who remain smokers, the widespread nature of exposure to ETS during pregnancy as well as during childhood, the known toxicology of tobacco smoke, and in particular sidestream smoke, characterized by a rich carcinogen content, the specific metabolism of foetuses and new-borns and finally the amount of epidemiologic data already available. We conducted a thorough review of the literature to identify studies either exclusively dealing with the effects of passive smoking on the occurrence of childhood cancers or more generally etiologic studies of cancer, be it overall or site-specific. We identified close to 50 publications presenting pertinent results from epidemiological investigations and about 50 more on mechanisms and metabolism, smoking in pregnancy and exposure to ETS as well as selected reviews and commentaries. Collaborative epidemiological studies were conducted in the United Kingdom (UK), USA, Sweden, Netherlands and internationally (France, Italy). In addition, other studies were also available from the USA, UK, Canada, Australia, Sweden, Italy, Denmark and People's Republic of China. The vast majority were case-control studies dealing with all cancers, leukaemia and lymphomas, central nervous system (CNS) tumours, Wilms' tumour, retinoblastoma, neuroblastoma, hepatoblastoma, rhabdomyosarcoma, bone and soft tissues tumours, germ cell tumours, as well as specific histological types of leukaemias, lymphomas or CNS tumours. No strong association between maternal smoking in pregnancy and/or exposure to ETS and childhood cancer is found. Yet, several studies found slightly increased relative risks, generally smaller than 1.5, i.e. the order of magnitude associated with some recognized hazards of exposure to ETS (1.2 to 1.3 for adult lung cancer and cardiovascular diseases). Tumours most often found associated with maternal smoking in pregnancy or ETS exposure are childhood brain tumours and leukaemia-lymphoma, with risks up to two or greater in selected studies. In a few studies, risks associated with paternal smoking are higher than the maternal ones. This evidence from human studies coupled with demonstration of genotoxic effects on the foetus of exposure to metabolites of tobacco smoke, and demonstrable presence of adducts should lead to strong recommendations aiming at fully protecting foetuses, new-borns and infants from tobacco smoke.

Health status and risk factors of seminomadic pastoralists in Mongolia: a geographical approach

The particular lifestyle of nomadic or seminomadic people has much to do with their health status. This discussion of the conceptual basis and some preliminary results of the 1992-94 health status and risk factor survey in Mongolia serves to highlight some of the relationships existing between the general health status and potential risk factors observed among pastoral nomads. In addition to graphic description of the data, a statistical analysis suggests significant associations between certain health status indicators and gender, location, lifestyle factors (e.g. smoking) socio-economic status, preventive health care and the physical environment. With regard to locational factors, there are strong regional differences in a wide-ranging number of health status indicators. The results of this study, obtained as they were at the threshold of Mongolia's economic and political transformation, will serve as a baseline against which to evaluate future changes in the health of Mongolians.

Urinary cotinine and parent history (questionnaire) as indicators of passive smoking and predictors of lower respiratory illness in infants

Studies of the effects of passive smoking on lower respiratory illness (LRI) have relied on questionnaires to measure exposure. We studied the association between two measures of passive smoking and the incidence of acute LRI in infants. We analyzed data from a community-based cohort study of respiratory illness during the first year of life in North Carolina. The incidence of LRI was determined by telephone calls at 2-week intervals. Environmental, demographic, and psychosocial risk factors for LRI were measured during home interviews. Tobacco smoke exposure was measured as the mean number of cigarettes smoked per day in the infant's presence. Smoke absorption by the infants was measured by the urinary cotinine/ creatinine ratio. Of the 485 infants in the study, 325 (67%) had telephone follow-up and at least two home interviews. In bivariate analyses, reported tobacco smoke exposure and urinary cotinine were associated with LRI. Only the association between reported exposure and LRI remained significant after adjusting for confounders, [adjusted incidence of LRI (episodes/child-year) non-exposed: 0.6; < or = 10 cigarettes/day: 0.9 (RR 1.5, 95% CI: 1.1, 2.0); > 10 cigarettes/day: 1.3 (RR 2.2, 95% CI: 1.3, 3.8)]. We conclude that infants reportedly exposed to tobacco smoke have an increased incidence of LRI. There are differences between questionnaire and biochemical measures of passive smoking. Urinary cotinine will not necessarily improve the validity of studies of the relationship of passive smoking to LRI in infants.

Telephone-guided placement and removal of nicotine monitors for the assessment of passive exposure to environmental tobacco smoke

The aim of this study was to determine the feasibility of telephone-guided placement of nicotine air sampling monitors in homes of women with infants. A monitor was mailed to homes in which the mother, her partner, or both were smokers, and a research assistant telephoned the woman and guided her through proper placement of the monitor according to a standard protocol. To assess the success of the guided placement, research assistants visited the homes of 50 women at the end of the two-week air-sampling period. The placement was determined to be correct if the monitor was positioned at least 1 ft from windows, more than 1 ft from the nearest corner of the room, and more than 2 ft from ashtrays. We had a 94% success rate for monitor placement in our study population, and our cost assessment showed that guided placement and removal cost approximately one-tenth the amount of methods requiring research assistants to conduct placements onsite. These results suggest that telephone-guided placement of monitors is an acceptable, inexpensive alternative to onsite placement by research assistants.

Evaluation of a home-based intervention program to reduce infant passive smoking and lower respiratory illness

We conducted a randomized controlled trial to determine whether a home-based intervention program could reduce infant passive smoking and lower respiratory illness. The intervention consisted of four nurse home visits during the first 6 months of life, designed to assist families to reduce the infant's exposure to tobacco smoke. Among the 121 infants of smoking mothers who completed the study, there was a significant difference in trend over the year between the intervention and the control groups in the amount of exposure to tobacco smoke; infants in the intervention group were exposed to 5.9 fewer cigarettes per day at 12 months. There was no group difference in infant urine cotinine excretion. The prevalence of persistent lower respiratory symptoms was lower among intervention-group infants of smoking mothers whose head of household had no education beyond high school: intervention group, 14.6%; and controls, 34.0%.

Central auditory processing in school-age children prenatally exposed to cigarette smoke

One hundred and ten, 6- to 11-year-old children from a low-risk, predominantly middle class sample who are participants in an ongoing longitudinal drug study were assessed using a central auditory processing task (SCAN) that made perceptual rather than linguistic demands. Maternal smoking during pregnancy was linearly associated with poorer performance on the overall SCAN and, particularly, the Competing Words subtest which may be an indication of the child's auditory maturation. The significant associations remained after adjusting for other drug use, demographic variables, and passive smoke exposure both during pregnancy and postnatally. The child's recent second-hand smoke exposure was evaluated by a parental questionnaire and by urine cotinine assay. Neither prenatal nor postnatal passive smoke exposure was statistically significantly associated with the SCAN results. However, among the children of nonsmokers, passive smoke exposure resulted in average scores similar to those of the prenatal light smoking group. The findings are discussed in relation to earlier observations that have reported an association between smoking during pregnancy and altered auditory functioning in the offspring.

Application of sample survey methods for modelling ratios to incidence densities

We describe ratio estimation methods for multivariately analysing incidence densities from prospective epidemiologic studies. Commonly used in survey data analysis, these ratio methods require minimal distributional assumptions and take into account the random variability in the at-risk periods. We illustrate their application with data from a study of lower respiratory illness (LRI) in children during the first year of life. One question of interest is whether children with passive exposure to tobacco smoke have a higher rate of LRI, on average, than those with no exposure and in a setting where age of child and season are taken into account. A second question is whether the relationship persists after adjusting for background variables such as family's socioeconomic status, crowding in the home, race, and type of feeding. The basic strategy consists of a two-step process in which we first estimate subgroup-specific incidence densities and their covariance matrix via a first-order Taylor series approximation. These estimates are used to test for differences in marginal rates of LRI between children exposed to tobacco smoke and those not exposed. We then fit a log-linear model to the estimated ratios in order to test for significant covariate effects. The ability to produce direct estimates of adjusted incidence density ratios for risk factors of interest is an important advantage of this approach. For comparison purposes and to address the limitations of the ratio method with respect to the number of covariates that can be controlled simultaneously, we consider survey logistic regression methods for the example data as well as logistic and Poisson regression models fitted via generalized estimating equation methods. Although the analysis strategy is illustrated with illness data from an epidemiologic study, the context of application is broader and includes, for example, data on adverse events from a clinical trial.

Smoking in child family day care homes: policies and practice in New South Wales

OBJECTIVES

To provide estimates of the numbers of New South Wales children in Family Day Care who may be exposed to environmental tobacco smoke while attending day care; to describe existing smoking policies; and to analyse these policies with the aim of providing guidelines for smoking policy in Family Day Care.

SETTING

All 109 Family Day Care schemes in NSW.

METHOD

Scheme coordinators were sent a questionnaire regarding the proportion of carers who smoked while caring for children; the nature, enforcement and experience of smoking policies; and barriers to implementation of a no-smoking policy.

RESULTS

A mean of 10% of Family Day Care caregivers were reported to smoke while caring for children (range, 0-60%). An estimated 2045 children were potentially exposed to environmental tobacco smoke in the 86 schemes which provided this information. Thirty-five per cent of schemes had formal no-smoking policies. A range of advantages, disadvantages and perceived practical and legal barriers to implementation of a no-smoking policy in Family Day Care were described. Forty-four per cent of schemes with no-smoking policies reported no implementation problems.

CONCLUSIONS

There is considerable potential for exposure of children to environmental tobacco smoke in Family Day Care homes. There is legal support for Family Day Care caregivers not to expose children under their care to environmental tobacco smoke. A formal (and enforced) no-smoking policy should exist in every Family Day Care scheme, and a "top-down" directive is most likely to be successful. The issue of other smokers in the caregiver's household needs to be specifically addressed in any such directive.

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.