Evidence for an association between environmental tobacco smoke exposure and birthweight: a meta-analysis and new data

Because of the strong association of active smoking with fetal growth retardation, increasing interest has focused on whether there is also an association with exposure to environmental tobacco smoke (ETS). We examined this issue in a retrospective study and by conducting a review of the literature and data pooling. In our study, nonsmoking women with singleton livebirths born in 1986–87 ( n  = 992) provided information on exposure to ETS for 1 h or more per day and paternal smoking. The risk of low birthweight (LBW, < 2500 g) was not increased in infants of ETS-exposed women, but there was a somewhat increased risk for LBW at term (adjusted odds ratio [OR] 1.8, 95% confidence interval [CI] 0.6, 4.8) and small-for-gestational-age (< 10th percentile of weight; OR = 1.4, 95% CI = 0.8, 2.5). These results were in the range of 16 other studies in the literature that had odds ratios from 1.0 to 2.2. A weighted average of the results of all studies on LBW at term or small-for-gestational-age yielded a pooled estimate of 1.2 [95% CI = 1.1, 1.3] in nonsmoking women. The pooled estimate of mean birthweight indicated a decrement of 28 g with ETS exposure of nonsmoking women [95% CI = −41, −16], with a greater decrement (about 40 g) seen among more homogeneous studies.     

Prenatal and childhood environmental tobacco smoke exposure and age at menarche

Ferris JS, Flom JD, Tehranifar P, Mayne ST, Terry MB. Prenatal and childhood environmental tobacco smoke exposure and age at menarche. Paediatric and Perinatal Epidemiology 2010; 24: 515–523. Previous studies have reported mixed results regarding the association between age at menarche and environmental tobacco smoke exposure, both prenatally and during early childhood; however, few studies have had data available during both time periods. The present study examined whether exposure to prenatal tobacco smoke (PTS) via maternal smoking during pregnancy or childhood environmental tobacco smoke (ETS) was associated with age at menarche in a multi‐ethnic birth cohort. With the uniquely available prospectively collected data on body size and growth at birth and in early life, we further examined whether the association between PTS and ETS exposure and age at menarche was mediated by these variables. From 2001 to 2006, we recruited 262 women born between 1959 and 1963 who were enrolled previously in a New York City site of the National Collaborative Perinatal Project. Mothers who smoked during pregnancy vs. those who did not were more likely to be White, younger, have more education and have lower birthweight babies. Daughters with heavy PTS exposure (≥20 cigarettes per day) had a later age at menarche (>12 years vs. ≤12 years), odds ratio (OR) = 2.1 [95% confidence interval (CI) 0.9, 5.0] compared with daughters with no PTS. Daughters exposed to only childhood ETS had a later age at menarche, OR = 2.1 [95% CI 1.0, 4.3], and those exposed to PTS and ETS combined had a statistically significant later age at menarche, OR = 2.2 [95% CI 1.1, 4.6] compared with daughters with no PTS and no ETS. These results did not change after further adjustment for birthweight and postnatal growth suggesting that exposure to PTS and ETS is associated with later age at menarche even after considering possible relationships with growth.     

Effects on birthweight of alcohol and caffeine consumption in smoking women.

STUDY OBJECTIVE--Previous work found no effect on birthweight of alcohol and caffeine consumption in non-smokers but such an effect was found in smokers. This report investigates further the effects on birthweight of alcohol and caffeine at three stages of pregnancy in smoking women. DESIGN--This was a prospective population study. SETTING--District general hospital in inner London. PARTICIPANTS--Out of 1309 women who completed all pregnancy interviews, 895 were excluded because they did not smoke, leaving a sample of 414 smokers. MEASUREMENTS AND MAIN RESULTS--Number and brand of cigarettes smoked, and quantity of alcohol and caffeine consumed were obtained by interview at booking, 28, and 36 weeks gestation. Birthweight was corrected for gestation and adjusted for maternal height, sex of infant and parity. The effect on birthweight of alcohol consumption was not explained by the amount smoked in terms of quantity and yield. Similarly the effect of caffeine was independent of smoking. When alcohol, caffeine, and smoking were analysed together, alcohol and caffeine were both associated with reductions in birthweight. Alcohol was associated with a reduction of up to 8% after adjusting for tobacco and caffeine intake, and caffeine was associated with a reduction of up to 6.5% after adjusting for tobacco and alcohol intake. Women who at booking were heavy smokers (greater than or equal to 13 cigarettes/day or greater than or equal to 15 mg carbon monoxide/cigarette), heavy drinkers (greater than or equal to 100 g/week alcohol), and had high caffeine intake (greater than or equal to 2801 mg/week) had a predicted reduction in mean birthweight of 18% (95% CI 11% to 24%). CONCLUSIONS--It is well known that women who smoke in pregnancy have smaller babies than non-smokers. Our study suggests that if these women also drink alcohol and high quantities of caffeine then the risk of poor fetal growth is increased even further.     

Preterm delivery and exposure to active and passive smoking during pregnancy: a case-control study from Italy

The aim of this study was to assess the relationship between preterm/early preterm delivery and active smoking as well as environmental tobacco smoke (ETS) exposure in a sample of pregnant Italian women. A case-control study was conducted in nine cities in Italy between October 1999 and September 2000. Cases of preterm birth were singleton babies born before the 37th gestational week; babies born before the 35th gestational week were considered early preterm births. Controls were babies with gestational ages >or= 37th week. A total of 299 preterm cases (including 105 early preterm) and 855 controls were analysed. A self-administered questionnaire was used to assess active smoking and ETS exposure, as well as potential confounders. Multivariable logistic regression analysis showed a relationship between active smoking during pregnancy and preterm/early preterm delivery [adjusted ORs: 1.53; 95% CI 1.05, 2.21 and 2.00; 95% CI 1.16, 3.45, respectively]. A dose-response relationship was found for the number of cigarettes smoked daily. The adjusted ORs were 1.54 and 1.69 for preterm babies and 1.90 and 2.46 for early preterm babies for 1-10 and >10 cigarettes/day respectively. ETS exposure was associated with early preterm delivery [adjusted OR 1.56; 95% CI 0.99, 2.46] with a dose-response relationship with the number of smokers in the home. Smoking during pregnancy was strongly associated with preterm delivery with a dose-response effect. ETS exposure in non-smoking women was associated only with early preterm delivery.     

The effect of maternal smoking during pregnancy on intellectual disabilities among 8-year-old children

Prenatal tobacco smoke exposure has been implicated as a risk factor for cognitive deficits in children. The purpose of this study is to examine the association between prenatal tobacco smoke exposure and diagnosis of intellectual disabilities (ID) among 8-year-old children living in Arkansas, Georgia, North Carolina and Utah. In 2002 and 2004, 965 ID case children were identified through a surveillance network and compared with the population of children born in the surveillance region during the same period ( n  = 104 607). Prenatal tobacco smoke exposure was determined from birth certificates. We estimated the effect of prenatal tobacco smoke exposure (none, <10, 10–19 and ≥20 cigarettes per day) on ID using logistic regression.
Generally, the risk of ID was mildly elevated among children whose mothers smoked ≥20 cigarettes per day during pregnancy [RR 1.34; 95% (confidence interval) CI 0.96, 1.87] after adjustment for maternal education, maternal race, maternal age, marital status, child sex, birth year and study site. However, the effect of exposure to ≥20 cigarettes per day significantly differed for males [RR 1.77, 95% CI 1.20, 2.62] compared with females [RR 0.81, 95% CI 0.44, 1.50]. Supplemental analyses reveal substantial confounding of this relationship by socio-economic indicators. A differential effect of tobacco smoke exposure on the risk of ID is suggested for males and females and deserves further investigation; however, the interpretation is tempered by the potential for residual confounding.     

Importance of exposure to gaseous and particulate phase components of tobacco smoke in active and passive smokers

Summary The uptake of tobacco smoke constituents from gaseous and particulate phases of mainstream smoke (MS), inhaled by smokers, and of environmental tobacco smoke (ETS), breathed in by non-smokers, was investigated in two experimental studies. Tobacco smoke uptake was quantified by measuring carboxyhemoglobin (COHb), nicotine and cotinine in plasma and urine and the data obtained were correlated with urinary excretion of thioethers and of mutagenic activity. An increase in all biochemical parameters was observed in smokers inhaling the complete MS of 24 cigarettes during 8 h, whereas only an increase in COHb and, to a minor degree, in urinary thioethers was found after smoking the gas phase of MS under similar conditions. Exposure of non-smokers to the gaseous phase of ETS or to whole ETS at similar high concentrations for 8 h led to identical increases in COM, plasma nicotine and cotinine as well as urinary excretion of nicotine and thioethers which were much lower than in smokers. Urinary mutagenicity was not found to be elevated under either ETS exposure condition. As shown by our results, the biomarkers most frequently used for uptake of tobacco smoke (nicotine and cotinine) indicate on the one hand the exposure to particulate phase constituents in smoking but on the other hand the exposure to gaseous phase constituents in passive smoking. Particle exposure during passive smoking seems to be low and a biomarker which indicates ETS particle exposure is as yet not available. These findings emphasize that risk extrapolations from active smoking to passive smoking which are based on cigarette equivalents or the use of one biomarker (e.g. cotinine) might be misleading.     

The influence of maternal cigarette smoking, snuff use and passive smoking on pregnancy outcomes: the Birth To Ten Study

This article describes the patterns and effects of maternal snuff use, cigarette smoking and exposure to environmental tobacco smoke during pregnancy on birthweight and gestational age, in women living in Johannesburg and Soweto in 1990. A cohort of 1593 women with singleton live births provided information about their own and household members' usage of tobacco products during pregnancy. The women completed a questionnaire while attending antenatal services. Data on gestational age and birthweight were obtained from birth records. Women who smoked cigarettes or used snuff during pregnancy accounted for 6.1% and 7.5% of the study population respectively. The mean birthweight of non-tobacco users was 3148 g [95% CI 3123, 3173] and that of the smokers 2982 g [95% CI 2875, 3090], resulting in a significantly lower mean birthweight of 165 g for babies of smoking mothers (P = 0.005). In contrast, women using snuff gave birth to infants with a mean birthweight of 3118 g [95% CI 3043, 3192], which is a non-significant (P = 0.52) decrease (29.4 g) in their infants' birthweights compared with those not using tobacco. A linear regression analysis identified short gestational age, female infant, a mother without hypertension during pregnancy, coloured (mixed racial ancestry), and Asian infants compared with black infants, lower parity, less than 12 years of education and smoking cigarettes as significant predictors of low birthweight, while the use of snuff during pregnancy was not associated with low birthweight. The snuff users, however, had a significant shorter gestational age than the other two groups of women. The birthweight reduction adjusted for possible confounders was 137 g [95% CI 26.6, 247.3 (P = 0.015)] for cigarette smokers and 17.1 g [95% CI -69.5, -102.7, P = 0.69] for snuff users respectively, compared with the birthweight of non-tobacco users. Among women who did not smoke cigarettes or use snuff, exposure to environmental tobacco smoke did not result in significant effects on the birthweight of their infants. In conclusion, infants of cigarette smokers had significantly lower birthweights than those of non-tobacco users or snuff users who are exposed to nicotine during pregnancy. Passive smoking did not affect birthweight significantly in this population.     

Environmental tobacco smoke and the risk of pancreatic cancer: findings from a Canadian population-based case-control study

BACKGROUND: Despite the fact that tobacco is a well-recognized risk factor for pancreatic cancer, no study has yet reported on the association between environmental tobacco smoke (ETS) and this malignancy. We investigated the relationship between pancreatic cancer and childhood and adult exposure to ETS using a case-control study design. METHODS: Our study population consisted of 583 pancreatic cancer cases and 4,813 population-based controls that were identified within 8 Canadian provinces between 1994 and 1997. Mail-out questionnaires were used to collect risk factor information and a lifetime residential and occupational history of exposure to ETS. RESULTS: Among never smokers, those who were exposed to ETS both as a child and as an adult had an odds ratio of 1.21 (95% CI=0.60-2.44) relative to those with no exposure. For active smoking, when the referent group consisted of never smokers who had not been regularly exposed to ETS, the risk increases were more pronounced with an increased number of years of smoking, cigarette pack-years, years since quit smoking, and average number of cigarettes smoked daily. CONCLUSIONS: Overall, our results are suggestive of a weak association between pancreatic cancer and ETS. Perhaps more importantly, they suggest that ETS smoking exposures may confound the risk of pancreatic cancer associated with active smoking measures commonly used in epidemiologic studies.     

Cord serum cotinine as a biomarker of fetal exposure to cigarette smoke at the end of pregnancy

This study investigated the association between biomarkers of fetal exposure to cigarette smoke at the end of pregnancy, cotinine in cord serum and in maternal and newborn urine samples, and quantitative measurement of smoking intake and exposure evaluated by maternal self-reported questionnaire. Study subjects were 429 mothers and their newborns from a hospital in Barcelona, Spain. A questionnaire including smoking habits was completed in the third trimester of pregnancy and on the day of delivery. Cotinine concentration in cord serum was associated with daily exposure to nicotine in nonsmokers and with daily nicotine intake in smokers. The geometric mean of cotinine concentration in cord serum statistically discriminated between newborns from nonexposed and exposed nonsmoking mothers, and between these two classes and smokers, and furthermore was able to differentiate levels of exposure to tobacco smoke and levels of intake stratified in tertiles. Urinary cotinine levels in newborns from nonsmoking mothers exposed to more than 4 mg nicotine daily were statistically different from levels in two other categories of exposure. Cotinine concentration in urine from newborns and from mothers did not differentiate between exposure and nonexposure to environmental tobacco smoke (ETS) in nonsmoking mothers. Cord serum cotinine appeared to be the most adequate biomarker of fetal exposure to smoking at the end of pregnancy, distinguishing not only active smoking from passive smoking, but also exposure to ETS from nonexposure.     

Nasopharyngeal carcinoma in Malaysian Chinese: occupational exposures to particles, formaldehyde and heat

BACKGROUND: During 1990-1992, 282 Chinese residents of Selangor and the Federal Territory, Malaysia with histologically confirmed nasopharyngeal carcinoma (NPC) were interviewed about occupational history, diet, alcohol consumption, and tobacco use, as were an equal number of Malaysian Chinese population controls, pair-matched to cases by age and sex. METHODS: Exposures to 20 kinds of workplace substances, solar and industrial heat, and cigarette smoke, were analysed by univariate and multivariate methods. RESULTS: Nasopharyngeal carcinoma was associated with occupational exposures to construction, metal and wood dusts; motor fuel and oil; paints and varnishes; certain other chemicals; industrial heat; solar heat from outdoor occupations; certain smokes; cigarette smoking; and childhood exposure to parental smoking. After adjustment for risk from diet and cigarette smoke, only wood dust (OR = 2.36; 95% CI : 1.33- 4.19), and industrial heat (OR = 2.21; 95% CI : 1.12-4.33) remained clearly associated. Wood dust remained statistically significant after further adjustment for social class. No significant crude or adjusted association was found between NPC and formaldehyde (adjusted OR = 0.71; 95% CI : 0.34-1.43). CONCLUSIONS: This study supports previous findings that some occupational inhalants are risk factors for NPC. The statistical effect of wood dust remained substantial after adjustment for diet, cigarette smoke, and social class. Intense industrial heat emerged as a previously unreported risk factor, statistically significant even after adjustment for diet and cigarette smoke. No association was found between NPC and formaldehyde.     

Low Birth Weight and Prenatal Exposure to Indoor Pollution from Tobacco Smoke and Wood Fuel Smoke: A Matched Case–Control Study in Gaza Strip

Maternal exposure to environmental tobacco smoke (ETS) is a major health hazard as it contains lower doses of the toxins that smokers?? inhale. Prenatal exposure to wood fuel smoke has been linked to delivering low birth weight (LBW) infants. The study aims to assess the association between prenatal exposure to ETS and wood fuel smoke and LBW. A case?Ccontrol study in ratio 1:1 was conducted in two hospitals with obstetric services in Gaza Strip. Subjects were selected during May?CJune and July?CAugust 2007 from attenders of Mbarak Hospital and Shifa Medical Centre, respectively. 184 (41.2%), and 79 (17.7%) out of 446 participants were exposed to environmental tobacco smoke and wood fuel smoke, respectively. Adjusted maternal exposure to ETS (especially the number of cigarettes smoked, water pipe and wood fuel smoke) was associated with LBW infants. Cigarette smoke exhibits an independent dose?Cresponse risk of LBW after adjusting for confounders. Prenatal exposure to cigarette smoke indoors is related to a reduction in birth weight of infants of ?237?g (95% CI: ?415, ?58) for pregnant women exposed to 1?C20 cigarettes per day and ?391?g (95% CI: ?642, ?140) for exposure to more than 20 cigarettes per day. Exposure to wood fuel smoke exhibits a reduction of infants?? adjusted mean birth weight by ?186?g (95% CI: ?354, ?19). Prenatal exposure to passive smoking and wood fuel smoke are independently associated with LBW. Both these factors are modifiable exposures that could possibly lead to a reduction of delivering LBW infants.     

Effects of tobacco smoke exposure on asthma prevalence and medical care use in North Carolina middle school children

OBJECTIVES: We sought to determine the effects of exposure to environmental tobacco smoke (ETS) and childhood cigarette smoking on asthma symptoms among middle school children in North Carolina. METHODS: During 1999-2000, information was collected from a survey completed by the children. Outcomes of asthma symptom reporting were regressed on tobacco smoke exposures. RESULTS: Children who currently smoked or reported any exposure to ETS were at increased risk of reporting active asthma symptoms. Exposure to ETS and childhood cigarette smoking was responsible for 15% of the asthma cases observed in the study population and $1.34 million in excess medical expenditures. CONCLUSIONS: Even at low levels of exposure, childhood cigarette smoking and ETS are independently associated with asthmatic symptoms.     

The relationship between home smoking bans and exposure to state tobacco control efforts and smoking behaviors

PURPOSE: To examine the relationship between home smoking bans and adult smokers' exposure to the statewide California Tobacco Control Program (TCP) and their cigarette smoking behavior. DESIGN: Cross-sectional survey that was part of the statewide Independent Evaluation of the California Tobacco Control, Prevention and Education Program. SETTING: Random telephone interviews within 18 California counties. SUBJECTS: A representative sample of 1315 adult smokers, aged 25 years and older. MEASURES: The telephone survey included questions about smoking behavior, quitting smoking, exposure to tobacco control program components, home smoking rules, and attitudes related to tobacco use and environmental tobacco smoke (ETS). RESULTS: Smokers with a home smoking ban were twice as likely (OR = 2.29; 95% CI 1.22, 4.29) to have heard of TCP community programs and three times more likely (OR = 3.18; 95% CI 1.34, 7.57) to have seen and talked about the ETS media spot than smokers with no home smoking policy. Multivariate regression models indicated that having a home smoking ban was related to smoking fewer cigarettes per day and greater interest in quitting smoking compared with smokers with no smoking rules in the home (p < .05). CONCLUSIONS: These findings suggest that smokers reporting exposure to the California TCP were more likely to have restrictive home smoking policies and that more restrictive home smoking policies were associated with reduced smoking behavior.     

Lifetime exposure to environmental tobacco smoke and cervical intraepithelial neoplasms among nonsmoking Taiwanese women

Cigarette smoke is one of the most important environmental risk factors for the development of cervical intraepithelial neoplasms (CINs). Given that the prevalence of cigarette smoking in Taiwanese women is very low, compared with Caucasian women (3-4% vs. approximately 28%, respectively), direct smoking is likely a minimal risk factor in the Taiwanese group. However, the evaluation of the association between indirect tobacco exposure, or exposure to environmental tobacco smoke (ETS), and CIN risk in Taiwanese women may be enlightening. The authors designed a community-based nested case-control study to examine the association between ETS exposure and CIN risk among Taiwanese women who were nonsmokers. The study was conducted in Chia-Yi, a city in southwestern Taiwan. The test population comprised adult females (n = 32,466) who had undergone Pap smear screening during the 14-mo period that preceded this study. Potential cases were chosen from individuals who demonstrated positive Pap smear results, which were indicative of at least a level II cervical intraepithelial neoplasm (i.e., > or = CIN2), as confirmed by cervical biopsy (n = 116). The authors chose 2 matched controls for each case; criteria used were (a) the 2 controls for each case had to be approximately the same age (+/- 2 yr) as the case; (b) each case and respective control lived in the same residential area; and (c) each control had a negative Pap smear, determined during the same time frame (+/- 6 mo) that the matched study subject was tested. A total of 100 study subjects and 197 control females (3 cases had only 1 control) underwent interviews by public health nurses, who obtained information about the participants' active and passive smoking histories and other potential risk factors. The incidence of cigarette smoking was low (5.0% [n = 5]) in study subjects and lower in controls (3.1% [n = 6]). The authors' final analysis was restricted to 89 nonsmoking pairs (89 subjects and 175 controls). Of the affected subjects, 85.4% reported exposure to passive smoke at home during their adulthood, vs. 61.1% of controls. The authors found that, after adjusting for other covariates, there was a 2.73-fold increased risk of contracting CIN (95% confidence interval [CI] = 1.31, 5.67) among ETS-exposed individuals. The authors assessed cumulative dose in terms of pack-years (i.e., average daily exposure [number of packs smoked] multiplied by the number of years the same exposure continued). Compared with nonsmokers, women exposed to 1-20 pack-yr and more than 20 pack-yr had 1.90-fold (95% CI = 0.72, 5.03) and 2.99-fold (95% CI = 1.10, 8.09) increased risks, respectively, of developing CIN. The authors concluded that lifetime ETS exposure is a major determinant for contracting cervical neoplasms among nonsmoking women in Taiwan.     

南方女性复发性流产环境因素分析

目的:探讨南方女性不明原因复发性流产(undentifiedrecurrentspontaneousabortion,URSA)流行病学因素。方法:对326例URSA及400例正常对照育龄妇女进行健康问卷调查,用Logistic回归模型,纳入体重指数(BMI)、自然流产家族史、吸烟史、被动吸烟史、饮酒史、饮咖啡史,找出有独立意义的环境危险因素,并对自然流产次数3次及≥4次者进行分层分析。结果:吸烟史、饮酒史和饮咖啡史不是URSA的危险因素,短时间被动吸烟(1h/天)及长时间被动吸烟(≥1h/天)是URSA的危险因素,OR及95%CI分别是2.30,1.50～3.52及4.76,3.24～6.99。家族史及BMI≥24.0kg/m2是URSA危险因素,OR及95%CI分别是2.12,1.28～3.49及1.55,1.12～2.14。结论:被动吸烟史、BMI≥24.0kg/m2、自然流产家族史是中国南方女性URSA独立危险因素。     

Assessment of chronic exposure to cigarette smoke and its change during pregnancy by segmental analysis of maternal hair nicotine

This study aimed to investigate the association between biomarkers of fetal exposure to smoking during the whole pregnancy, nicotine in maternal and newborns hair samples, and quantitative measurement of smoking intake and exposure evaluated by maternal self-reported questionnaire. Study subjects were 150 mothers and their newborns from a hospital in Barcelona. A questionnaire including smoking habits was completed in the third trimester of pregnancy and on the day of delivery. Nicotine content was measured in two subsequent segments of maternal hair accounting for the first and last months of pregnancy, and in fetal hair. The geometric mean of nicotine concentration in maternal hair discriminated between nonexposition (3.84 and 2.80 ng/mg in distal and proximal hair segment, respectively) and exposition to cigarette smoke during pregnancy (6.06 and 4.30 ng/mg in distal and proximal hair segment, respectively) (P<0.05), and between these two classes and active smoking (14.40 and 11.08 ng/mg in distal and proximal hair segment, respectively). Maternal hair nicotine was able to differentiate levels of exposure to tobacco smoke and levels of intake. Nicotine concentration in hair from newborns did not differentiate between exposure and nonexposure to environmental tobacco smoke (ETS) in nonsmoking mothers. Finally, chronic exposure to cigarette smoke during pregnancy, assessed by maternal hair nicotine, correlated negatively with anthropometric parameters of newborns.     

Environmental Tobacco Smoke and Lung Cancer Among Chinese Nonsmoking Males: Might Adenocarcinoma Be the Culprit?

No studies have specifically reported the association of lungadenocarcinoma with environmental tobacco smoke (ETS) exposureamong nonsmoking males. The objective of this study was to examinethe exposure-response relation between ETS exposure and lungcancer among nonsmoking males. In particular, the associationwith adenocarcinoma of the lung was studied. This is a population-based,case-referent study in Hong Kong during 2004–2006. A totalof 132 Chinese male nonsmokers with newly diagnosed primarylung cancer and 536 nonsmoking community referents were interviewedabout ETS exposures from the household and/or workplace, includingever ETS exposure, sources of exposure, number of smoking cohabitants/coworkers,and smoker-years. Univariate logistic regression analyses showeda weak association between all lung cancers and ever ETS exposurefrom the household and/or workplace (odds ratio (OR) = 1.11,95% confidence interval (CI): 0.74, 1.67), but an increasedrisk was restricted to adenocarcinoma (OR = 1.68, 95% CI: 1.00,2.38). After adjustment for family cancer history and otherconfounders, excess risk (OR = 1.62, 95% CI: 0.91, 2.88) stillpersisted for adenocarcinoma, although it was no longer statisticallysignificant. Exposure-response relations for adenocarcinomawere found with increasing levels of all ETS indices when exposuresfrom the household and workplaces were combined. The consistentexposure-response relations between ETS exposures and adenocarcinomasuggested a probable causal link, which would have to be confirmedby future larger studies. adenocarcinoma; lung neoplasms; tobacco smoke pollution     

Maternal prenatal cigarette, alcohol and illicit drug use and risk of infant leukaemia: a report from the Children's Oncology Group

Several case-control studies have evaluated associations between maternal smoking, alcohol consumption and illicit drug use during pregnancy and risk of childhood leukaemia. Few studies have specifically focused on infants (<1 year) with leukaemia, a group that is biologically and clinically distinct from older children. We present data from a Children's Oncology Group case-control study of 443 infants diagnosed with acute leukaemia [including acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML)] between 1996 and 2006 and 324 population controls. Mothers were queried about their cigarette, alcohol and illicit drug use 1 year before and throughout pregnancy. Odds ratios (ORs) and 95% confidence intervals [CI] were calculated using adjusted unconditional logistic regression models. Maternal smoking (>1 cigarette/day) and illicit drug use (any amount) before and/or during pregnancy were not significantly associated with infant leukaemia. Alcohol use (>1 drink/week) during pregnancy was inversely associated with infant leukaemia overall [OR = 0.64; 95% CI 0.43, 0.94], AML [OR = 0.49; 95% CI 0.28, 0.87], and leukaemia with mixed lineage leukaemia gene rearrangements ('MLL+') [OR = 0.59; 95% CI 0.36, 0.97]. While our results agree with the fairly consistent evidence that maternal cigarette smoking is not associated with childhood leukaemia, the data regarding alcohol and illicit drug use are not consistent with prior reports and are difficult to interpret. It is possible that unhealthy maternal behaviours during pregnancy, some of which carry potential legal consequences, may not be adequately measured using only self-report. Future case-control studies of childhood leukaemia that pursue these exposures may benefit from incorporation of validated instruments and/or biomarkers when feasible.     

Decrease in the prevalence of environmental tobacco smoke exposure in the home during the 1990s in families with children

OBJECTIVES: This study explored correlates with and changes in the prevalence of environmental tobacco smoke (ETS) exposure of children in the home. METHODS: We used multiple logistic regression to explore ETS exposures as reported in the 1992 and 2000 National Health Interview Survey. RESULTS: ETS exposure in homes with children declined from 35.6% to 25.1% (P <.001) between 1992 and 2000, whereas smoking prevalence declined 26.5% to 23.3%. Home ETS exposures were more prevalent among non-Hispanic Whites than among African Americans (adjusted odds ratio [AOR] = 0.702; 95% confidence interval [CI] = 0.614, 0.802), Asian Americans (AOR = 0.534; 95% CI = 0.378, 0.754), and Hispanics (AOR = 0.388; 95% CI = 0.294, 0.389). Exposures declined across all groups, with greater gains in higher education and income groups. CONCLUSIONS: Home ETS exposure declined sharply between 1992 and 2000, more than would be predicted by the decline in adult smoking prevalence.     

Cigarette smoking and exposure to environmental tobacco smoke in China: the international collaborative study of cardiovascular disease in Asia

OBJECTIVES: We estimated the prevalence of cigarette smoking and the extent of environmental tobacco smoke exposure (ETS) in the general population in China. METHODS: A cross-sectional survey was conducted on a nationally representative sample of 15540 Chinese adults aged 35-74 years in 2000-2001. Information on cigarette smoking was obtained by trained interviewers using a standard questionnaire. RESULTS: The prevalence of current cigarette smoking was much higher among men (60.2%) than among women (6.9%). Among nonsmokers, 12.1% of men and 51.3% of women reported exposure to ETS at home, and 26.7% of men and 26.2% of women reported exposure to ETS in their workplaces. On the basis of our findings, 147358000 Chinese men and 15895000 Chinese women aged 35-74 years were current cigarette smokers, 8658000 men and 108402000 women were exposed to ETS at home, and 19072000 men and 55372000 women were exposed to ETS in their workplaces. CONCLUSIONS: The high prevalence of cigarette smoking and environmental tobacco smoke exposure in the Chinese population indicates an urgent need for smoking prevention and cessation efforts.