Maternal smoking among blacks and whites

Pharmacological interventions for promoting smoking cessation during pregnancy

BACKGROUND

Tobacco smoking in pregnancy causes serious health problems for the developing fetus and mother. When used by non-pregnant smokers, pharmacotherapies (nicotine replacement therapy (NRT), bupropion, and varenicline) are effective for increasing smoking cessation, however their efficacy and safety in pregnancy remains unknown. Electronic cigarettes (ECs) are becoming widely used, but their efficacy and safety when used for smoking cessation in pregnancy are also unknown.

OBJECTIVES

To determine the efficacy and safety of smoking cessation pharmacotherapies and ECs used during pregnancy for smoking cessation in later pregnancy and after childbirth, and to determine adherence to smoking cessation pharmacotherapies and ECs for smoking cessation during pregnancy.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (20 May 2019), trial registers, and grey literature, and checked references of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) conducted in pregnant women, comparing smoking cessation pharmacotherapy or EC use with either placebo or no pharmacotherapy/EC control. We excluded quasi-randomised, cross-over, and within-participant designs, and RCTs with additional intervention components not matched between trial arms.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods. The primary efficacy outcome was smoking cessation in later pregnancy; safety was assessed by 11 outcomes (principally birth outcomes) that indicated neonatal and infant well-being. We also collated data on adherence to trial treatments. We calculated the risk ratio (RR) or mean difference (MD) and the 95% confidence intervals (CI) for each outcome for each study, where possible. We grouped eligible studies according to the type of comparison. We carried out meta-analyses where appropriate.

MAIN RESULTS

We included 11 trials that enrolled a total of 2412 pregnant women who smoked at enrolment, nine trials of NRT and two trials of bupropion as adjuncts to behavioural support, with comparable behavioural support provided in the control arms. No trials investigated varenicline or ECs. We assessed four trials as at low risk of bias overall. The overall certainty of the evidence was low across outcomes and comparisons as assessed using GRADE, with reductions in confidence due to risk of bias, imprecision, and inconsistency. Compared to placebo and non-placebo (behavioural support only) controls, there was low-certainty evidence that NRT increased the likelihood of smoking abstinence in later pregnancy (RR 1.37, 95% CI 1.08 to 1.74; I² = 34%, 9 studies, 2336 women). However, in subgroup analysis by comparator type, there was a subgroup difference between placebo-controlled and non-placebo controlled RCTs (test for subgroup differences P = 0.008). There was unclear evidence of an effect in placebo-controlled RCTs (RR 1.21, 95% CI 0.95 to 1.55; I² = 0%, 6 studies, 2063 women), whereas non-placebo-controlled trials showed clearer evidence of a benefit (RR 8.55, 95% CI 2.05 to 35.71; I² = 0%, 3 studies, 273 women). An additional subgroup analysis in which studies were grouped by the type of NRT used found no difference in the effectiveness of NRT in those using patches or fast-acting NRT (test for subgroup differences P = 0.08). There was no evidence of a difference between NRT and control groups in rates of miscarriage, stillbirth, premature birth, birthweight, low birthweight, admissions to neonatal intensive care, caesarean section, congenital abnormalities, or neonatal death. In one study infants born to women who had been randomised to NRT had higher rates of 'survival without developmental impairment' at two years of age compared to the placebo group. Non-serious adverse effects observed with NRT included headache, nausea, and local reactions (e.g. skin irritation from patches or foul taste from gum), but data could not be pooled. Adherence to NRT treatment regimens was generally low. We identified low-certainty evidence that there was no difference in smoking abstinence rates observed in later pregnancy in women using bupropion when compared to placebo control (RR 0.74, 95% CI 0.21 to 2.64; I² = 0%, 2 studies, 76 women). Evidence investigating the safety outcomes of bupropion use was sparse, but the existing evidence showed no difference between the bupropion and control group.

AUTHORS' CONCLUSIONS

NRT used for smoking cessation in pregnancy may increase smoking cessation rates in late pregnancy. However, this evidence is of low certainty, as the effect was not evident when potentially biased, non-placebo-controlled RCTs were excluded from the analysis. Future studies may therefore change this conclusion. We found no evidence that NRT has either positive or negative impacts on birth outcomes; however, the evidence for some of these outcomes was also judged to be of low certainty due to imprecision and inconsistency. We found no evidence that bupropion may be an effective aid for smoking cessation during pregnancy, and there was little evidence evaluating its safety in this population. Further research evidence on the efficacy and safety of pharmacotherapy and EC use for smoking cessation in pregnancy is needed, ideally from placebo-controlled RCTs that achieve higher adherence rates and that monitor infants' outcomes into childhood. Future RCTs of NRT should investigate higher doses than those tested in the studies included in this review.

Pharmacological interventions for promoting smoking cessation during pregnancy

BACKGROUND

Smoking in pregnancy is a public health problem. When used by non-pregnant smokers, pharmacotherapies (nicotine replacement therapy (NRT), bupropion and varenicline) are effective for smoking cessation, however, their efficacy and safety in pregnancy remains unknown. Electronic Nicotine Delivery Systems (ENDS), or e-cigarettes, are becoming widely used but their efficacy and safety when used for smoking cessation in pregnancy are also unknown.

OBJECTIVES

To determine the efficacy and safety of smoking cessation pharmacotherapies (including NRT, varenicline and bupropion), other medications, or ENDS when used for smoking cessation in pregnancy.

SEARCH METHODS

We searched the Pregnancy and Childbirth Group's Trials Register (11 July 2015), checked references of retrieved studies, and contacted authors.

SELECTION CRITERIA

Randomised controlled trials (RCTs) conducted in pregnant women with designs that permit the independent effects of any type of pharmacotherapy or ENDS on smoking cessation to be ascertained were eligible for inclusion.The following RCT designs are included.Placebo-RCTs: any form of NRT, other pharmacotherapy, or ENDS, with or without behavioural support/cognitive behaviour therapy (CBT), or brief advice, compared with an identical placebo and behavioural support of similar intensity.RCTs providing a comparison between i) any form of NRT, other pharmacotherapy, or ENDS added to behavioural support/CBT, or brief advice and ii) behavioural support of similar (ideally identical) intensity.Parallel- or cluster-randomised trials were eligible for inclusion. Quasi-randomised, cross-over and within-participant designs were not, due to the potential biases associated with these designs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias and also independently extracted data and cross checked individual outcomes of this process to ensure accuracy. The primary efficacy outcome was smoking cessation in later pregnancy (in all but one trial, at or around delivery); safety was assessed by 11 outcomes (principally birth outcomes) that indicated neonatal and infant well-being; and we also collated data on adherence with trial treatments.

MAIN RESULTS

This review includes a total of nine trials which enrolled 2210 pregnant smokers: eight trials of NRT and one trial of bupropion as adjuncts to behavioural support/CBT. The risk of bias was generally low across trials with virtually all domains of the 'Risk of bias' assessment tool being satisfied for the majority of studies. We found no trials investigating varenicline or ENDS. Compared to placebo and non-placebo controls, there was a difference in smoking rates observed in later pregnancy favouring use of NRT (risk ratio (RR) 1.41, 95% confidence interval (CI) 1.03 to 1.93, eight studies, 2199 women).  However, subgroup analysis of placebo-RCTs provided a lower RR in favour of NRT (RR 1.28, 95% CI 0.99 to 1.66, five studies, 1926 women), whereas within the two non-placebo RCTs there was a strong positive effect of NRT, (RR 8.51, 95% CI 2.05 to 35.28, three studies, 273 women; P value for random-effects subgroup interaction test = 0.01). There were no differences between NRT and control groups in rates of miscarriage, stillbirth, premature birth, birthweight, low birthweight, admissions to neonatal intensive care, caesarean section, congenital abnormalities or neonatal death. Compared to placebo group infants, at two years of age, infants born to women who had been randomised to NRT had higher rates of 'survival without developmental impairment' (one trial). Generally, adherence with trial NRT regimens was low. Non-serious side effects observed with NRT included headache, nausea and local reactions (e.g. skin irritation from patches or foul taste from gum), but these data could not be pooled.

AUTHORS' CONCLUSIONS

NRT used in pregnancy for smoking cessation increases smoking cessation rates measured in late pregnancy by approximately 40%. There is evidence, suggesting that when potentially-biased, non-placebo RCTs are excluded from analyses, NRT is no more effective than placebo. There is no evidence that NRT used for smoking cessation in pregnancy has either positive or negative impacts on birth outcomes. However, evidence from the only trial to have followed up infants after birth, suggests use of NRT promotes healthy developmental outcomes in infants. Further research evidence on NRT efficacy and safety is needed, ideally from placebo-controlled RCTs which achieve higher adherence rates and which monitor infants' outcomes into childhood. Accruing data suggests that it would be ethical for future RCTs to investigate higher doses of NRT than those tested in the included studies.

Pharmacological interventions for promoting smoking cessation during pregnancy

BACKGROUND

Smoking in pregnancy is a substantial public health problem. When used by non-pregnant smokers, pharmacotherapies [nicotine replacement therapy (NRT), bupropion and varenicline] are effective treatments for smoking cessation, however, their efficacy and safety in pregnancy remains unknown.

OBJECTIVES

To determine the efficacy and safety of smoking cessation pharmacotherapies, including NRT, varenicline and bupropion (or any other medications) when used to support smoking cessation in pregnancy.

SEARCH METHODS

We searched the Pregnancy and Childbirth Group's Trials Register (5 March 2012), checked references of retrieved studies and contacted authors in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) with designs that permit the independent effects of any type of NRT (e.g. patch, gum etc.) or any other pharmacotherapy on smoking cessation to be ascertained were eligible for inclusion. Trials must provide very similar (ideally identical) levels of behavioural support or cognitive behaviour therapy (CBT) to participants in active drug and comparator trial arms.The following RCT designs are considered acceptable.Placebo RCTs: any form of NRT or other pharmacotherapy, with or without behavioural support/CBT, or brief advice compared with placebo NRT and additional support of similar intensity.RCTs providing a comparison between i) behavioural support/CBT or brief advice and ii) any form of NRT or other pharmacotherapy added to behavioural support of similar (ideally identical) intensity.Parallel- or cluster-randomised design trials are eligible for inclusion. However, quasi-randomised, cross-over and within-participant designs are not eligible for inclusion due to the potential biases associated with these designs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias and extracted data. Two assessors independently extracted data and cross checked individual outcomes of this process to ensure accuracy. The primary efficacy outcome was smoking cessation in later pregnancy (in all but one trial, at or around delivery); safety was assessed by seven birth outcomes that indicated neonatal well being and we also collated data on adherence.

MAIN RESULTS

Six trials of NRT enrolling 1745 pregnant smokers were included; we found no trials of varenicline or bupropion. No statistically significant difference was seen for smoking cessation in later pregnancy after using NRT as compared to control (risk ratio (RR) 1.33, 95% confidence interval (CI) 0.93 to 1.91, six studies, 1745 women). Subgroup analysis comparing placebo-RCTs with those which did not use placebos found that efficacy estimates for cessation varied with trial design (placebo RCTs, RR 1.20, 95% CI 0.93 to 1.56, four studies, 1524 women; non-placebo RCTs, RR 7.81, 95% CI 1.51 to 40.35, two studies, 221 women; P value for random-effects subgroup interaction test = 0.03). There were no statistically significant differences in rates of miscarriage, stillbirth, premature birth, birthweight, low birthweight, admissions to neonatal intensive care or neonatal death between NRT or control groups.

AUTHORS' CONCLUSIONS

Nicotine replacement therapy is the only pharmacotherapy for smoking cessation that has been tested in RCTs conducted in pregnancy. There is insufficient evidence to determine whether or not NRT is effective or safe when used to promote smoking cessation in pregnancy or to determine whether or not using NRT has positive or negative impacts on birth outcomes. Further research evidence of efficacy and safety is needed, ideally from placebo-controlled RCTs that investigate higher doses of NRT than were tested in the included studies.

Smoking in pregnancy in West Virginia: does cessation/reduction improve perinatal outcomes?

To determine if pregnant women decreasing/quitting tobacco use will have improved fetal outcomes. Retrospective analysis of pregnant smokers from 6/1/2006-12/31/2007 who received prenatal care and delivered at a tertiary medical care center in West Virginia. Variables analyzed included birth certificate data linked to intervention program survey data. Patients were divided into four study groups: <8 cigarettes/day-no reduction, <8 cigarettes/day-reduction, ≥8 cigarettes/day-no reduction, and ≥8 cigarettes/day-reduction. Analysis performed using ANOVA one-way test for continuous variables and Chi-square for categorical variables. Inclusion criteria met by 250 patients. Twelve women (4.8%) quit smoking; 150 (60%) reduced; 27 (10.8%) increased; and 61 (24.4%) had no change. Comparing the four study groups for pre-term births (<37 weeks), 25% percent occurred in ≥8 no reduction group while 10% occurred in ≥8 with reduction group (P = 0.026). The high rate of preterm birth (25%) in the non-reducing group depended on 2 factors: (1) ≥8 cigarettes/day at beginning and (2) no reduction by the end of prenatal care. Finally, there was a statistically significant difference in birth weights between the two groups: ≥8 cigarettes/day with no reduction (2,872.6 g) versus <8 cigarettes/day with reduction (3,212.4 g) (P = 0.028). Smoking reduction/cessation lowered risk of pre-term delivery (<37 weeks) twofold. Encouraging patients who smoke ≥8 cigarettes/day during pregnancy to decrease/quit prior to delivery provides significant clinical benefit by decreasing the likelihood of preterm birth. These findings support tobacco cessation efforts as a means to improve birth outcome.

[Why do mothers smoke? Analyzing the influence of living circumstances and psychological factors on tobacco consumption among mothers with minor children]

Using a cross-sectional population sample of 3,129 women with minor children, this paper analyzes the impact of social and psychological factors on maternal smoking. Pearson's χ(2) was used for testing significance of differences between smoking prevalence and social as well as psychological factors. Adjusted effects of these factors were calculated by means of multiple logistic regression analysis. About 30% of mothers smoked daily and about 11% were heavy smokers ( ≥ 20 cigarettes/day). Lower educational degree was the most important predictor for daily tobacco consumption. But also fulltime employment, low income, distress due to conflicts with (former) partner, job-related burdens, and single motherhood enhanced the risk of maternal smoking, while household-related stress and having a young child was associated with less tobacco use. With respect to personal factors, dysfunctional coping patterns and depression showed a significant impact on tobacco use. Against expectations, active coping styles were not associated with lower but with increased smoking rates. In conclusion, it can be stated that maternal smoking has multiple causes, and that intervention programs should target both current living circumstances and psychological factors.

Interventions for promoting smoking cessation during pregnancy

BACKGROUND

Tobacco smoking in pregnancy remains one of the few preventable factors associated with complications in pregnancy, low birthweight, preterm birth and has serious long-term health implications for women and babies. Smoking in pregnancy is decreasing in high-income countries and increasing in low- to middle-income countries and is strongly associated with poverty, low educational attainment, poor social support and psychological illness.

OBJECTIVES

To assess the effects of smoking cessation interventions during pregnancy on smoking behaviour and perinatal health outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2008), the Cochrane Tobacco Addiction Group's Trials Register (June 2008), EMBASE, PsycLIT, and CINAHL (all from January 2003 to June 2008). We contacted trial authors to locate additional unpublished data.

SELECTION CRITERIA

Randomised controlled trials where smoking cessation during pregnancy was a primary aim of the intervention.

DATA COLLECTION AND ANALYSIS

Trials were identified and data extracted by one person and checked by a second. Subgroup analysis was conducted to assess the effect of risk of trial bias, intensity of the intervention and main intervention strategy used.

MAIN RESULTS

Seventy-two trials are included. Fifty-six randomised controlled trials (over 20,000 pregnant women) and nine cluster-randomised trials (over 5000 pregnant women) provided data on smoking cessation outcomes.There was a significant reduction in smoking in late pregnancy following interventions (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.93 to 0.96), an absolute difference of six in 100 women who stopped smoking during pregnancy. However, there is significant heterogeneity in the combined data (I(2) > 60%). In the trials with the lowest risk of bias, the interventions had less effect (RR 0.97, 95% CI 0.94 to 0.99), and lower heterogeneity (I(2) = 36%). Eight trials of smoking relapse prevention (over 1000 women) showed no statistically significant reduction in relapse.Smoking cessation interventions reduced low birthweight (RR 0.83, 95% CI 0.73 to 0.95) and preterm birth (RR 0.86, 95% CI 0.74 to 0.98), and there was a 53.91g (95% CI 10.44 g to 95.38 g) increase in mean birthweight. There were no statistically significant differences in neonatal intensive care unit admissions, very low birthweight, stillbirths, perinatal or neonatal mortality but these analyses had very limited power.

AUTHORS' CONCLUSIONS

Smoking cessation interventions in pregnancy reduce the proportion of women who continue to smoke in late pregnancy, and reduce low birthweight and preterm birth. Smoking cessation interventions in pregnancy need to be implemented in all maternity care settings. Given the difficulty many pregnant women addicted to tobacco have quitting during pregnancy, population-based measures to reduce smoking and social inequalities should be supported.

'Imagine all that smoke in their lungs': parents' perceptions of young children's tolerance of tobacco smoke

Despite knowing the risks to their children's health, parents continue to expose their children to tobacco smoke prior to and after their birth. This study explores the factors influencing parent's behaviour in preventing the exposure of their (unborn) children to environmental tobacco smoke (ETS) and any changes to their smoking behaviour in the home during the first years of their children's lives. Whether or not they stopped smoking during pregnancy, the women did not protect themselves from breathing in other people's smoke. Yet once the baby was born, parents actively protected the baby from environmental tobacco, believing that the lungs of newborn babies were too immature to tolerate smoke. This protection lasted only for a matter of weeks for some babies, or stopped when they were 6-12 months old, linked to their parent's belief that older babies could tolerate or avoid smoke. These findings suggest that changes made to smoking during the first weeks of a baby's life are unlikely to be sustained, and key messages about the risks if ETS exposure need to be delivered repeatedly over the first 2 years of life and re-enforced as the child gets older.

Widening ethnic disparities in infant mortality in southern Brazil: comparison of 3 birth cohorts

OBJECTIVES

We analyzed trends in mortality among infants born to White and to Black or mixed-race women in 3 population-based cohorts representing all births in 1982, 1993, and 2004 in Pelotas, southern Brazil.

METHODS

Births were assessed during daily visits to all maternity hospitals. Maternal skin color was classified by the interviewers as White or Black or multi-racial. We used logistic regression to adjust for socioeconomic, demographic, and health services variables.

RESULTS

The mortality rate among infants born to White mothers declined from 30.4 per 1000 live births in 1982 to 13.9 per 1000 in 2004, compared with 53.8 per 1000 to 30.4 per 1000 among those born to Black and mixed-race mothers. Differences for neonatal mortality were even more marked, with reductions of 47% and 11% for infants born to White and Black or mixed-race women, respectively. Adjusted analyses showed that ethnic group differences in neonatal and infant mortality were partly explained by differences in poverty and prenatal care.

CONCLUSIONS

Over a 22-year period, improvements in health indicators were greater for infants born to White women than for other infants. The widening racial gap requires special attention from policymakers.

The effect of single motherhood on smoking by socioeconomic status and race/ethnicity

We examined the association between parenting young children and smoking among US single women compared with married women, and whether this effect is moderated by socioeconomic status and race/ethnicity. Our main finding is that having children reduces smoking except among single white women, and women with low income. We used the Tobacco Use Supplement of the Current Population Survey, a nationally representative dataset (1995-96, n=70,019). Log-binomial regression analysis was used to estimate the association between parenting responsibility (i.e., presence of children aged 0-4 and 5-17) and daily smoking status, after taking into consideration marital status, income, and race/ethnicity. Single women faced a higher risk of smoking than married women. Parenting was protective against smoking among married women but not among single women. Additionally, among single women, the associations between parenting and smoking varied by income and race/ethnicity. Parenting increased the risk of smoking among single women in the lowest income quartile. Single black and Hispanic women with children had a risk of smoking similar to that of their childless counterparts. However, single white women with children were more likely to smoke than their childless counterparts. Smoking cessation interventions and programs to reduce environmental tobacco smoke should recognize that the co-occurrence of single motherhood, parenting responsibility and low-income may increase the risk of smoking. This is particularly significant given the rapid growth of the single women population, and their concentration in poverty in the USA. The finding that parenting is protective against smoking among single minority women, who presumably experience significant stressors, calls for a more thorough investigation of smoking behavior among minority women, and suggests the importance of stress buffers such as social support.

Desigualdades raciais, sociodemográficas e na assistência ao pré-natal e ao parto, 1999-2001

OBJETIVO: Analisar as desigualdades sociais e no acesso e utilização dos serviços de saúde em relação à cor da pele em amostra representativa de puérperas que demandaram atenção hospitalar ao parto. MÉTODOS: Trata-se de estudo transversal, realizado no Município do Rio de Janeiro, no qual foram amostradas 9.633 puérperas, sendo 5.002 brancas (51,9%), 2.796 pardas (29,0%) e 1.835 negras (19,0%), oriundas de maternidades públicas, conveniadas com o Sistema Único de Saúde e particulares no período de 1999 a 2001. Os dados foram coletados de prontuários médicos e por entrevistas com as mães no pós-parto imediato, aplicando questionários padronizados. Foram utilizados os testes de chi² para analisar a homogeneidade das proporções e t de Student para comparação de médias. A análise foi estratificada segundo o grau de instrução materna. RESULTADOS: Observou-se persistente situação desfavorável das mulheres de pele preta e parda em relação às brancas. Nas mulheres pretas e pardas são maiores as proporções de puérperas adolescentes, com baixa escolaridade, sem trabalho remunerado e vivendo sem companheiro. Sofrer agressão física, fumar, tentar interromper a gravidez e peregrinar em busca de atenção médica foram mais freqüentes nas negras seguidas das pardas e das brancas com baixa escolaridade. O grupo de elevado nível de escolaridade tem melhores indicadores, mas repete o mesmo padrão. Esse gradiente se mantém, em sentido inverso, quanto à satisfação com a assistência prestada no pré-natal e no parto. Constata-se a existência de duas formas de discriminação, por nível educacional e cor da pele. CONCLUSÕES: Verificaram-se dois níveis de discriminação, a educacional e a racial, que perpassam a esfera da atenção oferecida pelos serviços de saúde à população de puérperas do Município do Rio de Janeiro.

Interventions for promoting smoking cessation during pregnancy

BACKGROUND

Smoking remains one of the few potentially preventable factors associated with low birthweight, preterm birth and perinatal death.

OBJECTIVES

To assess the effects of smoking cessation programs implemented during pregnancy on the health of the fetus, infant, mother, and family.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Tobacco Addiction Group trials register (July 2003), MEDLINE (January 2002 to July 2003), EMBASE (January 2002 to July 2003), PsychLIT (January 2002 to July 2003), CINAHL (January 2002 to July 2003), and AUSTHEALTH (January 2002 to 2003). We contacted trial authors to locate additional unpublished data. We handsearched references of identified trials and recent obstetric journals.

SELECTION CRITERIA

Randomised and quasi-randomised trials of smoking cessation programs implemented during pregnancy.

DATA COLLECTION AND ANALYSIS

Four reviewers assessed trial quality and extracted data independently.

MAIN RESULTS

This review included 64 trials. Fifty-one randomised controlled trials (20,931 women) and six cluster-randomised trials (over 7500 women) provided data on smoking cessation and/or perinatal outcomes. Despite substantial variation in the intensity of the intervention and the extent of reminders and reinforcement through pregnancy, there was an increase in the median intensity of both 'usual care' and interventions over time. There was a significant reduction in smoking in the intervention groups of the 48 trials included: (relative risk (RR) 0.94, 95% confidence interval (CI) 0.93 to 0.95), an absolute difference of six in 100 women continuing to smoke. The 36 trials with validated smoking cessation had a similar reduction (RR 0.94, 95% CI 0.92 to 0.95). Smoking cessation interventions reduced low birthweight (RR 0.81, 95% CI 0.70 to 0.94) and preterm birth (RR 0.84, 95% CI 0.72 to 0.98), and there was a 33 g (95% CI 11 g to 55 g) increase in mean birthweight. There were no statistically significant differences in very low birthweight, stillbirths, perinatal or neonatal mortality but these analyses had very limited power. One intervention strategy, rewards plus social support (two trials), resulted in a significantly greater smoking reduction than other strategies (RR 0.77, 95% CI 0.72 to 0.82). Five trials of smoking relapse prevention (over 800 women) showed no statistically significant reduction in relapse.

REVIEWERS' CONCLUSIONS

Smoking cessation programs in pregnancy reduce the proportion of women who continue to smoke, and reduce low birthweight and preterm birth. The pooled trials have inadequate power to detect reductions in perinatal mortality or very low birthweight.

An ecological approach to understanding youth smoking trajectories: problems and prospects

Non-random patterns of aggregate youth smoking rates and trajectories across communities suggest that individual-level characteristics cannot account fully for the behavior in question. Instead, at least part of the explanation must lie somewhere within the community context. Such community-level contextual effects can impact directly both group and individual-level behavior (e.g. main effects), and they can also condition the effects of individual-level factors on individual behaviors (e.g. moderating effects). This paper reviews previous research examining community-level contextual effects regarding smoking and substance use more generally and identifies important limitations of this extant work, thus defining an agenda for future empirical studies. Next, the (in)compatibility of previous empirical findings with current theoretical models is discussed. In offering an alternative to these existing models, the paper concludes with presentation and discussion of a multi-level, integrated model of adolescent smoking trajectories. In this model, community/institutional forces are presumed to impact smoking above and beyond individual-level main effects. These posited community-level forces are broad and varied, representing school characteristics, neighborhood demographic characteristics, religious culture, media influence, economic context, health services and so on. In addition to exhibiting contextual main effects, the effects of community in the proposed multilevel model can be mediated by community-level processes, including the processes of control and socialization discussed herein. Also, community-level characteristics may interact in producing certain tobacco-use outcomes and, perhaps most importantly, they may moderate or condition the effects of interindividual differences on smoking.

Children's residential exposure to environmental tobacco smoke varies greatly between the Nordic countries

OBJECTIVE

To assess similarities and differences in the Nordic countries regarding ETS (environmental tobacco smoke) exposure in young children.

DESIGN

A population-based cross-sectional study comprising a randomly selected sample of 5,500 households which included a child born in 1992. Data were collected using a mailed anonymous questionnaire.

RESULTS

While the prevalence of household smoking was similar in all countries, there was a great difference between the countries with regard to child ETS exposure. Finnish parents were more likely than all other Nordic parents to protect their children from ETS and the situation was worst in Denmark and Iceland, where almost half of all households, and nine out of ten households containing daily smokers, exposed their children. Approximately eight out of ten current and former smokers in all countries stated that they had made efforts to change their smoking habits because of their children.

To what extent do parents strive to protect their children from environmental tobacco smoke in the Nordic countries? A population-based study

OBJECTIVE

To assess to what extent Nordic parents strive to protect their children from environmental tobacco smoke (ETS) at home.

DESIGN

A cross-sectional study using an anonymous questionnaire.

SUBJECTS AND SETTING

A stratified, random sample of 5500 households containing a child born during 1992, including 1500 households in Denmark and 1000 households in each of the countries of Finland, Iceland, Norway, and Sweden.

MAIN OUTCOME MEASURES

Smoking status of parents, prevalence and magnitude of weekly ETS exposure, rules regarding smoking in the home.

RESULTS

82% of current smokers reported having tried to change their smoking behaviour for the sake of their children. Of all parents who answered the questionnaire, 75% reported having introduced some rules to limit ETS in their home. In households where at least one parent smoked, 57% reported that children were exposed to ETS at home. Child exposure to ETS was most prevalent in single-parent households and in households in which parents had lower levels of education. However, these parents were not less likely than other smoking parents to report having tried to change their smoking behaviour for the sake of their children.

CONCLUSION

Environmental tobacco smoke at home is still a problem for many children in the Nordic countries. However, most smoking parents reported having made efforts to change their smoking behaviour for the sake of their children; and in approximately half of all households containing at least one daily smoker, parents reported protecting their children from ETS exposure in the home. Although actual exposure may be higher owing to possible under-reporting of ETS, our results indicate a general awareness in the Nordic countries of the potential negative effects of ETS on children.