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

Solid fuel combustion and adverse pregnancy outcomes: A nationwide study on stillbirth in India

OBJECTIVES

Stillbirth is a significant public health challenge in India, accounting for a substantial portion of the global burden. Exposure to household air pollution from solid fuel combustion during pregnancy has been associated with adverse pregnancy outcomes, including stillbirth. This study aimed to investigate the association between solid fuel use and stillbirth risk in India, utilizing data from the National Family Health Survey 5 (NFHS-5).

STUDY DESIGN

Nationwide cross-sectional study.

METHODS

The study employed data from the NFHS-5, a nationally representative cross-sectional survey conducted in India from 2019 to 2021. The study sample consisted of 204,723 women aged 15-49 years who had a pregnancy in the past 5 years preceding the survey. Stillbirth was calculated using calendar data, providing robust estimates. Logistic regression analysis was performed to assess the relationship between solid fuel use and stillbirth, adjusting for various sociodemographic and maternal factors.

RESULTS

The use of unclean cooking fuels was significantly associated with an increased risk of stillbirth (OR = 1.34, 95 % CI: 1.13-1.58, p < 0.001) compared to clean fuels. Other factors associated with higher stillbirth risk included rural residence, lower maternal education, belongingness to certain social categories, delivering at private healthcare facilities, limited antenatal visits, and undergoing caesarean delivery.

CONCLUSIONS

The findings highlight the detrimental impact of solid fuel use on stillbirth rates in India, underscoring the need for targeted interventions to promote cleaner cooking technologies and address socioeconomic disparities. Efforts to transition households towards cleaner energy sources and improve access to quality maternal healthcare services are crucial for reducing the burden of stillbirth in India.

Multicomponent Behavioural Intervention during Pregnancy to Reduce Home Exposure to Second-Hand Smoke: A Pilot Randomised Controlled Trial in Bangladesh and India

BACKGROUND

Pregnant women exposed to second-hand smoke (SHS) are at increased risk of poor birth outcomes. We piloted multicomponent behavioural intervention and trial methods in Bangalore, India, and Comilla, Bangladesh.

METHODS

A pilot individual randomised controlled trial with economic and process evaluation components was conducted. Non-tobacco-using pregnant women exposed to SHS were recruited from clinics and randomly allocated to intervention or control (educational leaflet) arms. The process evaluation captured feedback on the trial methods and intervention components. The economic component piloted a service use questionnaire. The primary outcome was saliva cotinine 3 months post-intervention.

RESULTS

Most pregnant women and many husbands engaged with the intervention and rated the components highly, although the cotinine report elicited some anxiety. Forty-eight (Comilla) and fifty-four (Bangalore) women were recruited. The retention at 3 months was 100% (Comilla) and 78% (Bangalore). Primary outcome data were available for 98% (Comilla) and 77% (Bangalore).

CONCLUSIONS

The multicomponent behavioural intervention was feasible to deliver and was acceptable to the interventionists, pregnant women, and husbands. With the intervention, it was possible to recruit, randomise, and retain pregnant women in Bangladesh and India. The cotinine data will inform sample size calculations for a future definitive trial.

Women's occupational status during pregnancy and preventive behaviour and health outcomes between 1998 and 2016 in France

BACKGROUND

Despite an improvement in preventive care and perinatal health in previous decades, social inequalities persist, particularly to the disadvantage of isolated or unemployed women. The objective was to analyse the evolution between 1998 and 2016 of the association between women's occupational status and perinatal outcomes.

METHODS

Data came from four national surveys performed in 1998, 2003, 2010 and 2016. Occupational status was defined by maternal employment status and type of occupation during pregnancy. Preventive behaviours (initiation of antenatal care, antenatal classes, breast feeding) and health outcomes (hospitalization, preterm birth, birth weight below the 10th percentile) were analysed by occupational status adjusted for other maternal characteristics, for each study year.

RESULTS

The studied sample included 12,497 women in 1998, 13,290 in 2003, 13,209 in 2010 and 11,179 in 2016. The proportion of employed women increased from 66% to 75% between 1998 and 2016, and that of housewives decreased from 22% to 12%. The proportion of preterm births globally increased between 1998 and 2016, especially for housewives. The proportion of low birthweight for gestational age (LBWGA) remained similar over the years. From 1998 to 2016, the differences between occupational groups persisted for preterm births and LBWGA.

CONCLUSIONS

Occupational groups exhibited strong social differences in preventive care over the entire study period and persisted in the recent data. As a major social indicator, women's occupational status during pregnancy has to be considered as a risk factor of poor preventive behaviour and unfavourable perinatal outcomes.

Association between secondhand smoke exposure in pregnant women and their socioeconomic status and its interaction with age: a cross-sectional study

Background

Existing evidence highlights that exposure to secondhand smoke (SHS) is a risk factor for pregnant women’s health and is possibly affected by individual characteristics. This study aimed to explore the effect of individual socioeconomic status (SES) on SHS exposure among pregnant women in the third trimester and the interaction effect of age.

Methods

A total of 678 nonsmoking pregnant women with a median age of 29.0 years from 14 communities in a medium-sized city were recruited for this survey. Exposure to SHS was defined as the self-reported smoking habit of a spouse/partner. Individual SES characteristics consisted of marital status, educational attainment, employment and per capita monthly income.

Results

There were 238 (35.1%) participants who suffered from SHS exposure. Compared to the pregnant women who were employed, those who were unemployed were more likely to suffer from SHS exposure (OR = 1.572, 95% CI: 1.013–2.441). Participants who had a high school or technical secondary school education were more likely to be exposed to SHS than those with a college education or above (OR = 1.601, 95% CI: 1.029–2.449). Advanced age was a protective factor for participants with a college education or above (OR = 0.939, 95% CI: 0.884–0.997), but age increased the risk of SHS exposure among women who had unstable marriages (OR = 1.256, 95% CI: 1.019–1.549).

Conclusion

Exposure to SHS was very common among pregnant women in the third trimester. Pregnant women with a low SES and an older age should be considered a key population for the implementation of public health interventions.

The impact of secondhand smoke exposure on the pregnancy outcome: a prospective cohort study among Egyptian community

Background

Secondhand smoke (SHS) exposure gained lesser interest than active smoking. There is evidence from previous studies that SHS exposure had negative effects on fetal growth. This study aimed to examine the effect of smoke exposure on pregnancy outcome and to evaluate the level of nicotine urinary end-product cotinine in pregnant women in the late trimester. We included 36 women with a history of SHS exposure and 48 women without a history of exposure; all were in last trimester of pregnancy. We measured cotinine level in urine and followed the two groups until delivery and recorded fetal outcomes. Fetal biophysical parameters and blood flow waveforms were measured using B-mode and Doppler ultrasonography, respectively.

Results

The total range of the urinary cotinine creatinine ratio (CCR) concentration in the SHS exposed pregnant women was 0.01–0.2, IQR = 0.18 ng/mg.cr, versus 0.01–0.1, and IQR = 0.03 ng/mg.cr in the non-exposed group. The mean value as well as the mean rank of CCR was significantly higher (0.1 ± 0.08 ng/mg.cr., 40.3 respectively) in the exposed pregnant women as compared to the non-exposed pregnant women ((0.04 ± 0.02), 29.3 respectively, p value < 0.05). Newborn of the exposed women had significantly low birth weight which negatively correlated with cotinine level and had a dose-response relationship.

Conclusions

SHS exposure had negative effects on fetal outcomes. Efforts should be utilized to increase awareness of the consequences of secondhand smoke on the fetus and strict follow-up of exposed women for early detection.

The effect of active and passive maternal smoking before and during pregnancy on neonatal weight at birth

INTRODUCTION

Smoking during pregnancy is a risk factor for adverse pregnancy outcomes. Data on the correlation between passive maternal smoking and pregnancy outcomes remain limited. We investigated the effect of active smoking and environmental tobacco smoke (ETS) during pregnancy on neonatal birthweight, including the risk for low birthweight (LBW).

MATERIAL AND METHODS

The study was conducted between 2010 and 2012. A group of 8625 women were surveyed during postpartum hospitalization. Outcome measures included mean birthweight of newborns. Additionally, odds ratios with confidence intervals were calculated to investigate the risk for LBW in active and passive smoking groups of mothers.

RESULTS

Lower birthweight (46 g - 307 g; p < 0.05) and a higher risk for LBW (OR = 1.35, 95% CI: 1.05-1.75; p < 0.05) were observed in all infants born to smoking mothers. A negative effect of ETS in pregnancy on the reduction of mean birthweight was also found. Additionally, we analyzed the cumulative effect of active and passive smoking on neonatal birthweight. A statistically significant reduction in neonatal weight at birth was found in a group of women who smoked actively and passively during pregnancy (130 g; p < 0.05).

CONCLUSIONS

Smoking is associated with decreased birthweight and in a group of active smoking mothers increased risk for LBW. This effect is dose-dependent and is also present in a group of women who smoked before pregnancy. There is also a cumulative effect of active smoking and ETS causing decreased neonatal birthweight and increased risk for low birthweight.

The association between maternal exposure to secondhand smoke during pregnancy and their children's cerebral palsy, Shandong, China

INTRODUCTION

Tobacco use poses a threat to the health of pregnant women and their children. Our study assessed the association between maternal exposure to secondhand smoke (SHS) during pregnancy and children's cerebral palsy (CP) in Shandong, China.

METHODS

In our observational study, 5067 mother-child pairs were included from Shandong Province, China. Mothers filled in questionnaires about exposure to SHS during pregnancy. Statistical analysis and logistic regression models were built in R program to estimate the association in adjusted odds ratio (AOR) between SHS exposure during pregnancy and risk of children's CP, after adjustment for potential confounders including delivery mode and baby's birthweight.

RESULTS

Exposure to SHS was noted among 3663 (72.3%) of the 5067 non-smoking mothers during their pregnancy. Of the 239 CP children within the study, 192 (80.3%) were exposed to SHS during pregnancy. Children born to mothers exposed to SHS during pregnancy had a higher risk of CP (AOR=1.44; 95% CI: 1.02-2.04) than those born to non-exposed mothers, the risk increased by exposure time in the logistic regression model. The association between SHS exposure during pregnancy and CP children remained significant when adjusting for delivery mode and infant's birthweight due to their significant association with CP, with an AOR of 1.46 (95% CI: 1.13-1.91) for 1-4 days/week and 1.63 (95% CI: 1.22-2.01) for 5-7 days/week exposure to SHS.

CONCLUSIONS

Our study suggests that maternal exposure to secondhand smoke during pregnancy is associated with children's CP. Future preventive interventions of CP should include strategies that target the antenatal women who are exposed to SHS.

Low birthweight of children is positively associated with mother's prenatal tobacco smoke exposure in Shanghai: a cross-sectional study

INTRODUCTION

Low birthweight (LBW) is a significant public health issue, and maternal smoking is the most prevalent preventable cause of LBW. But there is limited evidence on association of LBW among children and cigarette smoke exposure in mothers in China. In this cross-sectional study, we try to explore if the LBW in children is positively associated with mothers' prenatal cigarette smoke exposure.

METHODS

We selected 8, 586 mothers and their singleton children in 2018 in Songjiang district, Shanghai. Birthweight of children and gestational weeks of mother was identified by birth records in the hospital, we classified mothers' prenatal cigarette smoke status into the first-hand smoke (FHS) exposure and the second-hand smoke (SHS) exposure. We use SAS 9.1.3 software to calculate the prevalence of children's LBW and the prevalence of mothers' prenatal cigarette smoke exposure including FHS and SHS. Chi-square test and logistic regression were used to analyze the difference.

RESULTS

In 8, 586 women, The prenatal FHS and SHS exposure prevalence was 0.9 and 20.8%, respectively. The mean birthweight of children was 3315.5 g with a standard deviation of 497.2 g, the mean birthweight was 167.7 g and 66.1 g lower in children born to mothers with prenatally FHS and SHS exposure compared with those children whose mother were not exposed, respectively. The children's LBW prevalence was 4.7% in this study. By comparing with children whose mother were not exposed, the LBW prevalence was higher among children whose mother were prenatally exposed to FHS [OR (Odds Ratios) = 2.91, 95% confidence interval (CI) (1.49, 5.68)], and SHS [OR = 2.35, 95% CI (1.90, 2.89)].

CONCLUSIONS

Children's LBW is positively associated with mothers' prenatal tobacco smoke exposure both for FHS and SHS. So implementing tobacco control measures is crucial to lower smoking prevalence among women, and decrease smoking prevalence of their family members as well as work fellows.

Mothers' prenatal tobacco smoke exposure is positively associated with the occurrence of developmental coordination disorder among children aged 3-6 years: A cross-sectional study in a rural area of Shanghai, China

INTRODUCTION

Prenatal tobacco smoke exposure is a potential risk factor for developmental coordination disorder (DCD) in children, but evidence on the relationship between DCD in children and tobacco smoke exposure in women is limited in China. We conducted a cross-sectional study to understand the prevalence of prenatal tobacco smoke exposure among mothers and the prevalence of DCD among children and to explore if mothers’ prenatal tobacco smoke exposure is positively associated with the occurrence of DCD among children.

METHODS

During 2018, we sampled 8586 children aged 3–6 years and their mothers in Songjiang district, Shanghai. DCD in children was identified by MABC-2 screening combined with pediatrician confirmation. Prenatal tobacco smoke exposure among mothers was classified into firsthand smoke (FHS) and secondhand smoke (SHS) exposure. SAS 9.2 software was applied to calculate the prevalence of DCD in children, the prevalence of prenatal FHS and SHS exposure in mothers and to analyze the differences by chi-squared test and logistic regression.

RESULTS

Among the 8586 women, the prevalence of prenatal FHS and SHS exposure was 0.94% and 20.79%, respectively. The prevalence of DCD in children was 6.65%, which was significantly higher in boys (7.64%) than in girls (5.51%), and children aged 3 years (9.77%) had a higher prevalence of DCD than children aged 4, 5 or 6 years (7.44%, 5.27% and 4.28%, respectively). In comparison with children whose mother was not exposed to prenatal FHS or SHS, the odds of having DCD was higher in children whose mother was exposed to prenatal FHS (OR=4.42; 95% CI: 2.62–7.44) and SHS (OR=1.77; 95% CI: 1.47–2.14), even after adjustment for potential confounders.

CONCLUSIONS

The occurrence of DCD among children is positively associated with prenatal tobacco smoke exposure among the mothers. It is crucial to implement tobacco control measures to decrease the prevalence of smoking among pregnant women and SHS exposure at home as well as in the work environment.

ABBREVIATIONS

DCD: developmental coordination disorder, ADHD: attention deficit hyperactivity disorder, FHS: firsthand smoke, SHS: secondhand smoke, MABC-2: movement assessment battery for children-2nd edition, GATS: global adult tobacco survey, SD: standard deviation, OR: odds ratio, CI: confidence interval, DAGs: directed acyclic graphs.

Effect of Prenatal Smoke Exposure on Birth Weight: The Moderating Role of Maternal Depressive Symptoms

INTRODUCTION

Both prenatal smoke exposure and depression have been linked to lower birth weight, a risk factor for morbidity and mortality. Few studies have looked at the interaction between these risk factors and none have used a biomarker to objectively measure prenatal smoke exposure. The current study sought to examine independent and interactive effects of cotinine and depression on birth weight. The effect of race was also explored.

METHOD

Data were drawn from a prospective study of pregnant women (N = 568) in the southeastern United States. Maternal demographic, health information, depressive symptoms, and birth data were collected via self-report and medical record abstraction. Prenatal blood samples were assayed for cotinine.

RESULTS

Controlling for covariates, multiple regression analyses indicated that both cotinine and depressive symptoms independently predicted lower birth weight and a significant interaction was also observed. Upon probing the interaction, a negative association between cotinine levels and birth weight was found in the context of higher depression but not lower depression scores. Similarly, logistic regression analyses revealed a significant interaction between cotinine and depression, such that cotinine predicted having a baby less than 2500 g among women who fell above the indicated cutoff score. African American women had the highest levels of cotinine and lowest weight babies; however, race was not a significant moderator.

CONCLUSIONS

Results suggest prenatal smoke exposure has a greater negative effect on birth weight for women endorsing co-occurring depressive symptoms. Findings can inform targeted interventions and assist medical providers with identifying women at increased risk for poor perinatal outcomes.

IMPLICATIONS

Despite the common occurrence of smoking during pregnancy and prenatal depression, the interaction between these risk factors on birth weight has rarely been examined. Further, the extant results have been mixed, likely due in part to difficulties in measurement. The current study was the first to use prenatal cotinine to assess bias-free, continuous levels of prenatal smoke exposure. Results indicate that prenatal cotinine was a significant predictor of birth weight only in the context of maternal depressive symptoms. These findings have important implications for mitigating negative perinatal outcomes for pregnant women and their children.

Burden of disease attributable to second-hand smoke exposure: A systematic review

Our aim was to provide a systematic review of studies on the burden of disease due to second-hand smoke (SHS) exposure, reviewing methods, exposure assessment, diseases causally linked to SHS, health outcomes, and estimates available to date. A literature review of studies on the burden of disease from SHS exposure, available in PubMed and SCOPUS, published 2007-2018 in English language, was carried out following the PRISMA recommendations. Overall, 588 studies were first identified, and 94 were eligible. Seventy-two studies were included in the systematic review. Most of them were based on the comparative risk assessment approach, assessing SHS exposure using mainly surveys on exposure at home/workplaces. Diseases more frequently studied were: lung cancer, ischemic heart disease, stroke, chronic obstructive pulmonary disease, asthma and breast cancer in adults; lower respiratory tract infection, otitis media, asthma, sudden infant death syndrome and low birth weight in children. The SHS exposure assessment and the reported population attributable fractions (PAF) were largely heterogeneous. As an example, the PAF from lung cancer varied between 0.6% and 20.5%. Moreover, PAF were estimated applying relative risks and SHS exposures with no consistent definitions or with different age classes. The research gap on the SHS exposure burden is shrinking. However, estimates are not yet available for a number of countries, particularly the Middle Eastern and African countries, and not all diseases with the strongest evidence of causation, such as sudden infant death syndrome, have been explored. Moreover, in some cases the applied methodology revealed relatively low quality of data.

Antenatal exposure to second hand smoke of non-smoking mothers and growth rate of their infants

Objectives

There is limited evidence on the effect of exposure to second hand smoke (SHS) in non-smoking pregnant mothers and infant health. We assessed the effects of maternal antenatal exposure to SHS on infant growth rate, and secondarily, on birth weight, birth length and head circumference at birth.

Methods

In this prospective cohort, 305 mother-infant pairs were studied. Mothers filled out questionnaires about exposure to SHS in pregnancy at the 3^rd trimester of pregnancy. Infant anthropometry was performed at birth, day 7, and months 1, 2, 4, and 6, postnatally. Linear mixed modeling and linear regression were used to calculate growth rates over the first 6 months. The association between SHS-exposure with growth rate and birth sizes was assessed using multivariate linear regression adjusted for confounders, with SHS as both number of cigarettes and as groups (no exposure, SHS < 23 cigarettes, SHS ≥ 23 cigarettes).

Results

Seventy-three mothers were not exposed and 232 were exposed. SHS exposure (per cigarette) was not related to gain in weight, length, head circumference, and weight for length. However, infants born to mothers exposed to ≥ 23 cigarettes/d had lower head circumference gain (-0.32 mm/m, 95% CI -0.60, -0.03) than those born to non-exposed mothers. SHS exposure (per cigarette) was not related to birth weight, length, and head circumference, but exposure to ≥ 23 cigarettes was related to lower head circumference at birth (-11.09 mm, -20.03, -2.16).

Conclusions

Heavy antenatal exposure to SHS in non-smoking mothers results in reduced neonatal head circumference at birth and head circumference gain over the first 6 months of life. Our findings show no clear relations between exposure to SHS during pregnancy and other markers of neonatal growth and birth size.

Comparison of Knowledge about Smoking and Passive Smoking and Urinary Cotinine Levels in Pregnant Women and their Partners in Mongolia: A Cross-sectional Study

This study aimed to compare knowledge about smoking, including passive smoking, and urinary cotinine (UC) levels in pregnant women and their partners in Mongolia. The study was conducted between November 2015 and January 2016 in Darkhan-Uul Province, Mongolia. Pregnant women with less than 20 weeks' gestation were recruited, and their partners were also invited to participate. Self-administered questionnaires and urine samples were used to collect data. Knowledge about smoking including passive smoking was measured using 14 questions. Data were analyzed using a Student's t-test, a chi-squared test, a one-way analysis of variance, and the Tukey-Kramer method for post-hoc analysis. Correlations were measured by computing Pearson's r or Spearman's ρ. A total of 508 pregnant women and 227 partners participated in this study; of these, 221 couples' data were analyzed. Pregnant women's scores on knowledge about smoking and passive smoking were significantly higher than those of their partners (9.4 ± 2.9 and 8.7 ± 3.1, respectively; p = 0.017). Pregnant women's and their partners' scores were slightly correlated (r = 0.163, p = 0.015). Pregnant women's and their partners' UC levels were significantly correlated (ρ = 0.250, p < 0.001). This study is the first to examine knowledge about smoking and passive smoking and UC levels among pregnant women and their partners in Mongolia. Because pregnant women's and their partners' scores and UC levels were positively correlated, health education on the harm caused by smoking and passive smoking should be provided to both pregnant women and their partners.

Effects of national smoke-free legislation on the rates of preterm births and low birthweights in Taiwan

This study evaluated the effects of partial and complete island-wide smoking bans on perinatal outcomes in Taiwan. Trends were determined in the yearly prevalence rates for preterm births and low birth weight (LBW) for a 1978 to 1997 pre-ban period, a 1998 to 2008 Phase 1 partial ban period, and a 2009 to 2016 Phase 2 complete ban period. Poisson regression with a yearly time-series model was employed to determine alterations in trends in prevalence rates for preterm births and LBW. Compared with pre-ban period, the rate ratio (RR) for Phase 1 preterm births was 0.969 (95% confidence interval [CI] = 0.968-0.971) and Phase 2 0.995 (95% CI = 0.992-0.998). The Phase 1 RR LBW fell 0.4% (95% CI = 0.2%-0.5%), but Phase 2 RR rose 1.7% (95% CI = 1.4%-2.1%). Data indicated that the risk of preterm births and LBW in Taiwan was reduced significantly after implementation of the smoking ban. These findings are in agreement with growing evidence suggesting that smoke-free legislation exerted a beneficial health effect on pregnant women and their newborn infants.

Fetal exposure to maternal active and secondhand smoking with offspring early-life growth in the Healthy Start study

BACKGROUND

Previous studies have modeled the association between fetal exposure to tobacco smoke and body mass index (BMI) growth trajectories, but not the timing of catch-up growth. Research on fetal exposure to maternal secondhand smoking is limited.

OBJECTIVES

To explore the associations between fetal exposure to maternal active and secondhand smoking with body composition at birth and BMI growth trajectories through age 3 years.

METHODS

We followed 630 mother-child pairs enrolled in the Healthy Start cohort through age 3 years. Maternal urinary cotinine was measured at ~ 27 weeks gestation. Neonatal body composition was measured using air displacement plethysmography. Child weight and length/height were abstracted from medical records. Linear regression models examined the association between cotinine categories (no exposure, secondhand smoke, active smoking) with weight, fat mass, fat-free mass, and percent fat mass at birth. A mixed-effects regression model estimated the association between cotinine categories and BMI.

RESULTS

Compared to unexposed offspring, birth weight was significantly lower among offspring born to active smokers (-343-g; 95% CI: -473, -213), but not among offspring of women exposed to secondhand smoke (-47-g; 95% CI: -130, 36). There was no significant difference in the rate of BMI growth over time between offspring of active and secondhand smokers (p = 0.58). Therefore, our final model included a single growth rate parameter for the combined exposure groups of active and secondhand smokers. The rate of BMI growth for the combined exposed group was significantly more rapid (0.27 kg/m² per year; 95% CI: 0.05, 0.69; p < 0.01) than the unexposed.

CONCLUSIONS

Offspring prenatally exposed to maternal active or secondhand smoking experience rapid and similar BMI growth in the first three years of life. Given the long-term consequences of rapid weight gain in early childhood, it is important to encourage pregnant women to quit smoking and limit their exposure to secondhand smoke.

Environmental tobacco smoke exposure during pregnancy has limited effect on infant birthweight and umbilical vein endothelial nitric oxide synthase

INTRODUCTION

Women who smoke, deliver significantly smaller infants. These infants have reduced levels of the vasodilator endothelial nitric oxide synthase (eNOS) levels in the umbilical vessels, which may reduce fetal growth. Serum cotinine, the degradation product of nicotine, can be used to determine the level of tobacco exposure. Newborns of environmental smokers are suggested to be smaller and shorter in weight, length, and head circumference. eNOS levels have not yet been studied in these infants. We investigated the existence of a relation between maternal environmental tobacco smoke exposure, eNOS activity, concentration, and birthweight.

MATERIAL AND METHODS

We included 263 healthy singleton pregnancies categorized into three groups according to measured cotinine levels: 175 nonsmokers, 38 smokers, and 50 environmental smokers. Cotinine was quantified by mass spectrometry with a detection limit of .2 ng/mL; eNOS activity and concentration were measured in endothelial cells (ECs) of the umbilical vein.

RESULTS

Infants born to environmental smokers had similar weights to infants born to nonsmokers (47 g heavier, P = .48). Cotinine concentrations were .06/.09/.12 ng/mL (quartiles) in infants born to nonsmokers, .27/.37/.81 ng/mL in infants born to women exposed to environmental tobacco smoke, and 43.0/63.8/108.1 ng/mL in infants born to smokers. The eNOS concentration was 1.65 ± .92 ng/10⁶ ECs (mean ± SD) in nonsmokers and 1.71 ± 1.00 ng/10⁶ ECs in environmental smokers. The eNOS activity was 52.0 ± 20.6 pmol l-citrulline/min/10⁶ ECs in nonsmokers and 48.7 ± 19.8 pmol l-citrulline/min/10⁶ ECs in environmental smokers.

CONCLUSIONS

Infants born to environmental smokers, as judged by umbilical serum cotinine levels close to .2 ng/mL, are not associated with lower birthweight or reduced eNOS activity, or concentration in the fetal vascular bed.

Impact of Smoking Ban on Passive Smoke Exposure in Pregnant Non-Smokers in the Southeastern United States

Prenatal passive smoke exposure raises risk for negative birth outcomes. Legislation regulating public smoking has been shown to impact exposure levels, though fewer studies involving pregnant women have been conducted within the U.S. where bans are inconsistent across regions. This study examined the effect of a ban enacted in the southeastern U.S. on pregnant women's cotinine levels. Additional analyses compared self-reported exposure to cotinine and identified characteristics associated with passive exposure. Pregnant women (N = 851) were recruited prospectively between 2005 and 2011 in North Carolina. Sociodemographic and health data were collected via surveys; maternal blood samples were assayed for cotinine. Among non-active smokers who provided self-report data regarding passive exposure (N = 503), 20% were inconsistent with corresponding cotinine. Among all non-smokers (N = 668), being unmarried, African American, and less educated were each associated with greater passive exposure. Controlling for covariates, mean cotinine was higher prior to the ban compared to after, F(1, 640) = 24.65, p < 0.001. Results suggest that banning smoking in public spaces may reduce passive smoke exposure for non-smoking pregnant women. These data are some of the first to examine the impact of legislation on passive smoke exposure in pregnant women within the U.S. using a biomarker and can inform policy in regions lacking comprehensive smoke-free legislation.

Correlation between tobacco control policies and preterm births and low birth weight in Europe

OBJECTIVE

To assess the correlation between tobacco control policies- particularly smoking bans in work and public places-and the prevalence of preterm births and low birth weight in the European countries.

METHODS

This is an ecological study and the unit of analysis set at the country level. Tobacco control data in Europe were obtained for the years 2010 and 2013 as measured by the Tobacco Control Scale (TCS), which reflects the level of implementation of tobacco control policies. Prevalence data for preterm births and low birth weight were obtained from two sources: the European Perinatal Health Report (EPHR), which provides data for 2010, and the Eurostat data, which includes the years 2013 and 2014. We analyzed the correlation between the TCS score and the prevalence of preterm birth and low birth weight in the European countries by means of Spearman (rsp) rank-correlation coefficients and their 95% confidence intervals (95%CI).

RESULTS

The 2010 TCS was negatively correlated with the prevalence of preterm births before week 37 (rsp = -0.51; 95% CI: -0.77, -0.15; p = 0.006) and week 32 (rsp = -0.42; 95%CI: -0.73, -0.01; p = 0.030) and with the prevalence of the low birth weight (< 2500g, (rsp = -0.42; 95% CI: -0.66, -0.09; p = 0.028) in European countries in 2010. We found a statistically significant inverse correlation between the level of restrictions on smoking in public places and the prevalence of low birth weight (< 2500g rsp: -0.54; 95%CI: -0.72, -0.10; p = 0.017).

CONCLUSION

The level of smoke-free legislation in European countries correlates with lower preterm birth prevalence rates at the ecological level. Given the important negative effects of premature births for the public health system, these data support greater implementation of smoke-free policies and tend to support the implementation of tobacco control policies, but more research is needed.

Prevalence and risk factors of secondhand smoke (SHS) exposure among pregnant women in Mongolia

This cross-sectional study investigated the prevalence of smoking and secondhand smoking (SHS) among pregnant women in Darkhan-Uul Province, Mongolia, using urinary cotinine (UC) levels, and clarified the factors related to SHS exposure. It targeted pregnant women who underwent antenatal health check-ups from November 2015 to January 2016. Self-administered questionnaires and urine samples were used to collect data. Using UC levels as the criterion, it was found that the prevalence of smokers (>100 ng/ml) among 493 pregnant women was 11.8%, while SHS exposure (≥5 ng/ml) among nonsmokers was 44.8%. Older and highly educated women had lower odds of SHS exposure (p = 0.006 and 0.002, respectively). Furthermore, nonsmoking pregnant women from homes where smoking was permitted had higher odds of SHS exposure compared to women from homes where smoking was not permitted. These results suggest that community guidance programs, such as home smoking cessation that include families, are necessary.

Awareness of health effects of exposure to secondhand smoke from cigarettes: A cross-sectional study of never-smoked adult primary care patients in Eastern Nigeria

Background:

Cigarette smoking whether actively or passively is a growing public health problem. Despite the wealth of information on the hazards of active cigarette smoking, awareness of the health effects of passive smoking on human population is often neglected in Nigeria.

Aim:

The study was aimed at describing the awareness of health effects of exposure to secondhand smoke from cigarettes among never-smoked adult primary care patients in Eastern Nigeria.

Materials and Methods:

A hospital-based study carried out on a cross-section of 500 adult patients in a primary care clinic in Nigeria. Data were collected using pretested, structured, and interviewer-administered questionnaire. Exposure to secondhand smoke was defined as exposure to cigarette smoke in a never-smoked adult patient in the previous 1 year. Data were analyzed using Statistical Package for Social Sciences version 21 for the calculation of percentages for categorical variables. Bivariate analysis involving Chi-square test was used to test for significance of association between categorical variables at P < 0.05.

Results:

The age of the respondents ranged from 18 to 74 years, with a mean age of 36 ± 12.4 years. There were 180 (36.0%) males with 320 (64%) females, with a sex ratio of 1.8. Awareness of general health effects of secondhand smoke on adults, children, and pregnant women was 95.6%, 92.8%, and 65.2%, respectively. The most common specific health effects the respondents were aware for adults, children, and obstetric population were lung cancer (95.6%), precipitation of asthmatic condition (92.8%), and delivery of small babies (65.2%), respectively. The predominant source of awareness of information was radio (93.6%). Awareness of general health effects of exposure to secondhand smoke on adults (P = 0.041), children (P = 0.031), and obstetrics population (P = 0.02) was significantly associated with exposure status.

Conclusion:

The most common health effects of secondhand smoke the respondents had highest awareness were lung cancer, precipitation of asthmatic attacks, and delivery of small babies in adults, children, and obstetric population, respectively. Awareness of general health effects on adults, children, and obstetrics population was significantly associated with exposure status. The current level of awareness should be improved while effort should be intensified to address identified areas of low level of awareness.

The Impacts of Cord Blood Cotinine and Glutathione-S-Transferase Gene Polymorphisms on Birth Outcome

BACKGROUND

This study aimed to investigate the association between cord blood cotinine levels and birth outcome, and to determine whether fetal metabolic gene polymorphisms of glutathione-S-transferase (GST) modulate the effect of environmental tobacco smoke exposure during pregnancy.

METHODS

This study included 328 maternal and neonatal pairs. Maternal and cord blood cotinine levels were measured using high performance liquid chromatography. The GST T1 (GSTT1) and GST M1 (GSTM1) polymorphisms were examined using the polymerase chain reaction method. The birth outcomes included birth weight, length, and head circumference, and the risks of having low birth weight and being small for gestational age (SGA).

RESULTS

Cord cotinine level had a dose-dependent impact on the reduction of birth weight, length, and head circumference in newborns. Elevation of cord blood cotinine concentration increased the rate of SGA and low birth weight. The neonates who had GSTT1 or GSTM1 polymorphism were associated with an increased risk of being SGA. A combination of the GSTT1 and GSTM1 null genotype exacerbated the effect of maternal environmental tobacco smoke exposure on SGA more than the presence of either genotype alone (odds ratio=8.90, 95% confidence interval=1.00-79.5).

CONCLUSION

Cord blood cotinine adversely affects birth outcomes. GSTT1 and GSTM1 null genotype may modify the effect of cord blood cotinine on birth outcomes.

Modeling lifetime costs and health outcomes attributable to secondhand smoke exposure at home among Korean adult women

PURPOSE

The aim of this research is to estimate lifetime costs and health consequences for Korean adult women who were exposed to secondhand smoke (SHS) at home.

METHODS

A Markov model was developed to project the lifetime healthcare costs and health outcomes of a hypothetical cohort of Korean women who are 40 years old and were married to current smokers. The Korean epidemiological data were used to reflect the natural history of SHS-exposed and non-exposed women. The direct healthcare costs (in 2014 US dollars) and quality-adjusted life years (QALYs) were annually discounted at 5% to reflect time preference. The time horizon of the analysis was lifetime and the cycle length was 1 year. Deterministic and probabilistic sensitivity analyses were conducted.

RESULTS

In the absence of SHS exposure, Korean women will live 41.32 years or 34.56 QALYs before discount, which corresponded to 17.29 years or 15.35 QALYs after discount. The SHS-exposed women were predicted to live 37.91 years and 31.08 QALYs before discount and 16.76 years and 14.62 QALYs after discount. The estimated lifetime healthcare cost per woman in the SHS non-exposed group was US$11 214 before the discount and US$2465 after discount. The negative impact of SHS exposure on health outcomes and healthcare costs escalated as the time horizon increased, suggesting that the adverse impact of SHS exposure may have higher impact on the later part of the lifetime. The result was consistent across a wide range of assumptions.

CONCLUSION

Life expectancy might underestimate the impact of SHS exposure on health outcomes, especially if the time horizon of the analysis is not long enough. Early intervention on smoking behaviour could substantially reduce direct healthcare costs and improve quality of life attributable to SHS exposure.

Pregnancy outcome and cord blood cotinine level: A cross-sectional comparative study between secondhand smokers and non-secondhand smokers

OBJECTIVE

To compare the pregnancy outcome and cord blood cotinine levels between secondhand smokers and non-secondhand smokers.

STUDY DESIGN

This was a cross-sectional comparative study in a Malaysian tertiary obstetric hospital involving 200 non-smoking pregnant women at term, of whom 100 were secondhand smokers and 100 were non-secondhand smokers. Those with multiple pregnancies, with a body mass index (BMI) of more than 30kg/m² or who delivered by Caesarean section were excluded. The participants' basic demographic details, delivery details, neonatal outcome and placental weight were recorded. Umbilical cord blood samples were obtained, and cord blood cotinine levels were measured with a Cotinine ELISA kit. The primary outcomes were baby's birth weight, length, and head circumference, Apgar score at 5min and placental weight. The secondary outcome was difference in cord blood cotinine levels between the two groups and the correlation of these differences with the neonatal outcome.

RESULTS

The secondhand smoker group had significantly lower baby weight (2.94±0.31kg vs 3.05±0.40kg), head circumference (30.87±2.35cm vs 37.13±2.36cm), length (46.58±1.95cm vs 51.53±2.05cm) and placental weight (520±73.5g vs 596±61.3g) and significantly higher cord blood cotinine levels (16.35±12.84ng/mL vs 0.56±0.22ng/mL). Cord blood cotinine levels had significant negative correlations with placental weight (r=-0.461), baby's weight (r=-0.297), baby's head circumference (r=-0.501) and baby's length (r=-0.374).

CONCLUSION

Secondhand smoke increases the incidence of adverse pregnancy outcomes (newborns'anthropometric measurements and placental weight) and causes higher cord blood cotinine levels.

Prenatal exposure to fine particles and polycyclic aromatic hydrocarbons and birth outcomes: a two-pollutant approach

BACKGROUND

Previous epidemiologic studies have considered the effects of individual air pollutants on birth outcomes, whereas a multiple-pollutant approach is more relevant to public health policy.

OBJECTIVES

The present study compared the observed effect sizes of prenatal fine particulate matter (PM_2.5) and polycyclic aromatic hydrocarbons (PAH) (a component of PM_2.5) exposures on birth outcome deficits, assessed by the single vs. two-pollutant approaches.

METHODS

The study sample included 455 term infants born in Krakow to non-smoking mothers, among whom personal exposures to PM_2.5 and PAH were monitored in the second trimester of pregnancy. The exposure effect estimates (unstandardized and standardized regression coefficients) on birth outcomes were determined using multivariable linear regression models, accounting for relevant covariates.

RESULTS

In the single-pollutant approach, each pollutant was inversely associated with all birth outcomes. The effect size of prenatal PAH exposure on birth weight and length was twice that of PM_2.5, in terms of standardized coefficients. In the two-pollutant approach, the negative effect of PM_2.5 on birth weight and length, adjusted for PAH exposure, lost its significance. The standardized effect of PAH on birth weight was 10-fold stronger (β = -0.20, p = 0.004) than that estimated for PM_2.5 (β = -0.02, p = 0.757).

CONCLUSION

The results provide evidence that PAH had a greater impact on several measures of fetal development, especially birth weight, than PM_2.5. Though in the single-pollutant models PM_2.5 had a significant impact on birth outcomes, this effect appears to be mediated by PAH.

Air pollution in perspective: Health risks of air pollution expressed in equivalent numbers of passively smoked cigarettes

BACKGROUND

Although the health effects of long term exposure to air pollution are well established, it is difficult to effectively communicate the health risks of this (largely invisible) risk factor to the public and policy makers. The purpose of this study is to develop a method that expresses the health effects of air pollution in an equivalent number of daily passively smoked cigarettes.

METHODS

Defined changes in PM2.5, nitrogen dioxide (NO2) and Black Carbon (BC) concentration were expressed into number of passively smoked cigarettes, based on equivalent health risks for four outcome measures: Low Birth Weight (<2500g at term), decreased lung function (FEV1), cardiovascular mortality and lung cancer. To describe the strength of the relationship with ETS and air pollutants, we summarized the epidemiological literature using published or new meta-analyses.

RESULTS

Realistic increments of 10µg/m(3) in PM2.5 and NO2 concentration and a 1µg/m(3) increment in BC concentration correspond to on average (standard error in parentheses) 5.5 (1.6), 2.5 (0.6) and 4.0 (1.2) passively smoked cigarettes per day across the four health endpoints, respectively. The uncertainty reflects differences in equivalence between the health endpoints and uncertainty in the concentration response functions. The health risk of living along a major freeway in Amsterdam is, compared to a counterfactual situation with 'clean' air, equivalent to 10 daily passively smoked cigarettes..

CONCLUSIONS

We developed a method that expresses the health risks of air pollution and the health benefits of better air quality in a simple, appealing manner. The method can be used both at the national/regional and the local level. Evaluation of the usefulness of the method as a communication tool is needed.

Pregnant women's secondhand smoke exposure and receipt of screening and brief advice by prenatal care providers in Argentina and Uruguay

Secondhand smoke (SHS) exposure has negative effects on maternal and infant health. SHS exposure among pregnant women in Argentina and Uruguay has not been previously described, nor has the proportion of those who have received screening and advice to avoid SHS during prenatal care. Women who attended one of 21 clusters of publicly-funded prenatal care clinics were interviewed regarding SHS exposure during pregnancy at their delivery hospitalization during 2011-2012. Analyses were conducted using SURVEYFREQ procedure in SAS version 9.3 to account for prenatal clinic clusters. Of 3,427 pregnant women, 43.4 % had a partner who smoked, 52.3 % lived with household members who smoked cigarettes, and 34.4 % had no or partial smoke-free home rule. Of 528 pregnant women who worked outside of the home, 21.6 % reported past month SHS exposure at work and 38.1 % reported no or partial smoke-free work policy. Overall, 35.9 % of women were exposed to SHS at home or work. In at least one prenatal care visit, 67.2 % of women were screened for SHS exposure, and 56.6 % received advice to avoid SHS. Also, 52.6 % of women always avoided SHS for their unborn baby's health. In summary, a third of pregnant women attending publicly-funded prenatal clinics were exposed to SHS, and only half of pregnant women always avoided SHS for their unborn baby's health. Provider screening and advice rates can be improved in these prenatal care settings, as all pregnant women should be screened and advised of the harms of SHS and how to avoid it.

The challenge of mothers learning about secondhand smoke (MLASS): a quasi-experimental, mixed methods feasibility study

BACKGROUND

Exposure to secondhand smoke (SHS) in the antenatal and postnatal period is associated with a detrimental health impact to the foetus and newborn baby and is recognised as a preventable public health challenge. The aim of the mother's learning about secondhand smoke (MLASS) study was to test the feasibility of delivering and evaluating the effectiveness of a smoke-free homes (SFH) health education intervention in the antenatal and postnatal period to reduce foetal and newborn exposure to SHS.

METHODS

Pregnant women aged 17-40 years old who attended their first community-based antenatal appointment in Leeds, UK, were eligible to participate if they currently smoked, or if they were non-smokers but lived in a household where someone else smoked, or had regular visitors to the home who smoked. A SFH health education intervention was delivered at four time points by community midwives and health visitors. Outcome measures included self-reported level of household smoking restrictions and SHS exposure in pregnant women who did not smoke during pregnancy and in the newborn baby, measured by salivary and urine cotinine levels, respectively. We planned to conduct focus group discussions with participants and health professionals. A post hoc survey of pregnant women was conducted at the recruitment site.

RESULTS

Eight pregnant women were recruited over a 6-month recruitment period. Of the 65 eligible pregnant women approached, 57 (88 %) declined to participate in the study. The majority declined to participate due to lack of interest in the study. In the post hoc survey, the majority of pregnant women reported that they were already implementing household smoking restrictions to reduce SHS; only a small number had no household smoking restrictions.

CONCLUSIONS

The post hoc survey identified women who could benefit from a SFH intervention; therefore, future studies should consider what SFH means to pregnant women and may wish to target those not currently implementing household smoking restrictions. Future recruitment strategies in studies of an SFH intervention in the context of maternity service pressures needs careful consideration; this includes the capacity to undertake the research, the recruitment setting, the criteria for individuals requiring the intervention, and individuals' willingness to engage with such research.

Developing a smoke free homes initiative in Kerala, India

BACKGROUND

Results of the Global Adult Tobacco Survey in Kerala, India found that 42 % of adults were exposed to second hand smoke (SHS) inside the home. Formative research carried out in rural Kerala suggests that exposure may be much higher. Numerous studies have called for research and intervention on SHS exposure among women and children as an important component of maternal and child health activities.

METHODS

Community-based participatory research was carried out in Kerala. First, a survey was conducted to assess prevalence of SHS exposure in households. Next, a proof of concept study was conducted to develop and test the feasibility of a community-wide smoke free homes initiative. Educational materials were developed and pretested in focus groups. After feasibility was established, pilot studies were implemented in two other communities. Post intervention, surveys were conducted as a means of assessing changes in community support.

RESULTS

At baseline, between 70 and 80 % of male smokers regularly smoked inside the home. Over 80 % of women had asked their husband not to do so. Most women felt powerless to change their husband's behavior. When women were asked about supporting a smoke free homes intervention, 88 % expressed support for the idea, but many expressed doubt that their husbands would comply. Educational meetings were held to discuss the harms of second hand smoke. Community leaders signed a declaration that their community was part of the smoke free homes initiative. Six months post intervention a survey was conducted in these communities; between 34 and 59 % of men who smoked no longer smoked in their home.

CONCLUSIONS

The smoke free homes initiative is based on the principle of collective efficacy. Recognizing the difficulty for individual women to effect change in their household, the movement establishes a smoke free community mandate. Based on evaluation data from two pilot studies, we can project that between a 30 and 60 % reduction of smoking in the home may be achieved, the effect size determined by how well the smoke free home steps are implemented, the characteristics of the community, and the motivation of community level facilitators.

Nuclear and mitochondrial DNA alterations in newborns with prenatal exposure to cigarette smoke

Newborns exposed to maternal cigarette smoke (CS) in utero have an increased risk of developing chronic diseases, cancer, and acquiring decreased cognitive function in adulthood. Although the literature reports many deleterious effects associated with maternal cigarette smoking on the fetus, the molecular alterations and mechanisms of action are not yet clear. Smoking may act directly on nuclear DNA by inducing mutations or epigenetic modifications. Recent studies also indicate that smoking may act on mitochondrial DNA by inducing a change in the number of copies to make up for the damage caused by smoking on the respiratory chain and lack of energy. In addition, individual genetic susceptibility plays a significant role in determining the effects of smoking during development. Furthermore, prior exposure of paternal and maternal gametes to cigarette smoke may affect the health of the developing individual, not only the in utero exposure. This review examines the genetic and epigenetic alterations in nuclear and mitochondrial DNA associated with smoke exposure during the most sensitive periods of development (prior to conception, prenatal and early postnatal) and assesses how such changes may have consequences for both fetal growth and development.

Designs of two randomized, community-based trials to assess the impact of alternative cookstove installation on respiratory illness among young children and reproductive outcomes in rural Nepal

Background

Acute lower respiratory infections (ALRI) are a leading cause of death among children. Low birthweight is prevalent in South Asia and associated with increased risks of mortality, and morbidity, high levels of indoor household air pollution caused by open burning of biomass fuels are common and associated with high rates of ALRI and low birthweight. Alternative stove designs that burn biomass fuel more efficiently have been proposed as one method for reducing these high exposures and lowering rates of these disorders. We designed two randomized trials to test this hypothesis.

Methods/design

We conducted a pair of community-based, randomized trials of alternative cookstove installation in a rural district in southern Nepal. Phase one was a cluster randomized, modified step-wedge design using an alternative biomass stove with a chimney. A pre-installation period of morbidity assessment and household environmental assessment was conducted for six months in all households. This was followed by a one year step-wedge phase with 12 monthly steps for clusters of households to receive the alternative stove. The timing of alternative stove introduction was randomized. This step-wedge phase was followed in all households by another six month follow-up phase. Eligibility criteria for phase one included household informed consent, the presence of a married woman of reproductive age (15–30 yrs) or a child < 36 months. Children were followed until 36 months of age or the end of the trial. Pregnancies were identified and followed until completion or end of the trial. Phase two was an individually randomized trial of the same alternative biomass stove versus liquid propane gas stove in a subset of households that participated in phase one. Follow-up for phase two was 12 months following stove installation. Eligibility criteria included the same components as phase one except children were only enrolled for morbidity follow-up if they were less than 24 months.

The primary outcomes included: incidence of ALRI in children and birthweight.

Discussion

We presented the design and methods of two randomized trials of alternative cookstoves on rates of ALRI and birthweight.

Trial registration

Clinicaltrials.gov (NCT00786877, Nov. 5, 2008).

Transgenerational exposure to environmental tobacco smoke

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

The influence of maternal smoking and exposure to residential ETS on pregnancy outcomes: a retrospective national study

In a nationwide study of Serbian births, in 2008, we estimated the influence of maternal prenatal smoking and environmental tobacco smoke (ETS) exposure on birth outcomes. Using stratified two-stage random cluster sampling, 2,721 women were interviewed in-person (response rates 98.1 %), and 2,613 singleton live births were included. Date of birth, gender, birthweight, birth height and head circumference were copied from the official hospital Birth Certificate. Six exposure categories were defined according to mother's smoking history and exposure to ETS. We calculated adjusted mean values and group differences by analysis of covariance, and adjusted odds ratios for the low birthweight (LBW < 2,500 g). Compared to the reference category (non-smoking, non-exposed to ETS) we observed birthweight reductions in infants whose mothers smoked continuously during the pregnancy and were exposed to ETS (-162.6 g) and whose mothers were not exposed to ETS (-173 g) (p = 0.000, and p = 0.003, respectively), as well as reduction in birth length (-1.01 and -1.06 cm; p = 0.003 and p = 0.000, respectively). Reduction in birthweight and birth length related to exposure categories was not linear. Adjusted OR for LBW was almost tripled for mothers who smoked over the entire pregnancy and were non-exposed to ETS (aOR 2.85; 95 % CI 1.46-5.08), and who were exposed to ETS (aOR 2.68; 95 % CI 1.15-6.25). Our results showed strong effects of smoking throughout the pregnancy on reduced birthweight, birth length and head circumference, and increased risk for LBW. We were not able to detect an effect for ETS exposure alone.

Clinical interventions to reduce secondhand smoke exposure among pregnant women: a systematic review

OBJECTIVE

To conduct a systematic review of clinical interventions to reduce secondhand smoke (SHS) exposure among non-smoking pregnant women.

DATA SOURCES

We searched 16 databases for publications from 1990 to January 2013, with no language restrictions.

STUDY SELECTION

Papers were included if they met the following criteria: (1) the study population included non-smoking pregnant women exposed to SHS, (2) the clinical interventions were intended to reduce SHS exposure at home, (3) the study included a control group and (4) outcomes included either reduced SHS exposure of non-smoking pregnant women at home or quit rates among smoking partners during the pregnancy of the woman.

DATA EXTRACTION

Two coders independently reviewed each abstract or full text to identify eligible papers. Two abstractors independently coded papers based on US Preventive Services Task Force criteria for study quality (good, fair, poor), and studies without biochemically-verified outcome measures were considered poor quality.

DATA SYNTHESIS

From 4670 papers, we identified five studies that met our inclusion criteria: four focused on reducing SHS exposure among non-smoking pregnant women, and one focused on providing cessation support for smoking partners of pregnant women. All were randomised controlled trials, and all reported positive findings. Three studies were judged poor quality because outcome measures were not biochemically-verified, and two were considered fair quality.

CONCLUSIONS

Clinical interventions delivered in prenatal care settings appear to reduce SHS exposure, but study weaknesses limit our ability to draw firm conclusions. More rigorous studies, using biochemical validation, are needed to identify strategies for reducing SHS exposure in pregnant women.

Parental smoking during pregnancy and its association with low birth weight, small for gestational age, and preterm birth offspring: a birth cohort study

BACKGROUND

Intrauterine exposure to tobacco smoke has been discerned as an important risk factor for low birth weight (LBW), small for gestational age (SGA), and preterm birth infants. In this cohort study, we investigated the association of the amount of parental smoking during the different pregnancy stages with birth weight and the incidence of preterm delivery.

METHODS

Our study population was acquired from the Taiwan Birth Cohort Study. Between June 2005 and July 2006, 21,248 postpartum women were interviewed 6 months after their deliveries by a structured questionnaire. The parents were divided into four groups according to the amount of smoking during preconception, the first trimester, and the second and third trimesters. The relationships of parental smoking with gestational age and birth weight during the different pregnancy stages were assessed using multivariate linear regression. Multiple logistic regression analyses were performed to estimate the odds ratios and 95% confidence intervals of preterm delivery, LBW, and SGA infants during the different parental smoking status and the different pregnancy stages.

RESULTS

After adjusting for the physical and socioeconomic status of the parents and for paternal smoking during the same period, we found that maternal smoking decreased birth weight. Compared with the nonsmoking groups, all the maternal smoking groups had higher incidences of LBW, SGA, and preterm birth infants, especially when the mothers smoked >20 cigarettes/day. The association of paternal smoking with LBW, SGA, and preterm birth infants was insignificant.

CONCLUSION

Maternal smoking is responsible for increased incidences of LBW and preterm delivery of babies, and therefore, smoking cessation/reduction should be advised to pregnant women to reduce morbidities in their neonates. Further studies are needed to clarify the correlation of fetal health with passive smoking, including exposure to environmental tobacco smoke and to other smokers in the family.

Total prohibition of smoking but not partial restriction effectively reduced exposure to tobacco smoke among restaurant workers in Finland

OBJECTIVES

To assess work-related exposure to tobacco smoke in Finnish restaurants, a series of nationwide questionnaire surveys were conducted among restaurant workers and the levels of indoor air nicotine concentrations were measured in restaurants. The survey aimed to evaluate the impact of the smoke-free legislation in general and in particular after the total smoking ban launched in 2007.

MATERIALS AND METHODS

In 2003-2010, four national questionnaire surveys were conducted among restaurant workers and the concentration of nicotine in indoor air was measured in different types of restaurants, bars and nightclubs.

RESULTS

Between 2003 and 2010, the proportion of restaurant workers reporting occupational exposure to tobacco smoke dropped from 59% to 11%. Among pub workers, the decrease was from 97% to 18% and in workers of dining restaurants from 49% to 10%, respectively. The median concentration of nicotine in indoor air of all restaurants decreased from 11.7 μg/m(3) to 0.1 μg/m(3). The most significant decrease was detected in pubs where the decrease was from 16.1 μg/m(3) to 0.1 μg/m(3). Among all restaurant workers, in 2003-2010 the prevalence of daily smokers was reduced from 39% to 31% in men and from 35% to 25% in women.

CONCLUSION

Total prohibition of smoking but not partial restriction in restaurants was effective in reducing work-related exposure to tobacco smoke. Strict tobacco legislation may partly be associated with the significant decrease of daily smoking prevalence among restaurant workers.

Towards estimating the burden of disease attributable to second-hand smoke exposure in Polish children

OBJECTIVES

To estimate the burden of disease attributable to second-hand smoke (SHS) exposure in Polish children in terms of the number of deaths and disability adjusted life years (DALYs) due to lower respiratory infections (LRI), otitis media (OM), asthma, low birth weight (LBW) and sudden infant death syndrome (SIDS).

MATERIALS AND METHODS

Estimates of SHS exposure in children and in pregnant women as well as information concerning maternal smoking were derived from a national survey, the Global Youth Tobacco Survey, and the Global Adult Tobacco Survey in Poland. Mortality data (LRI, OM, asthma, and SIDS), the number of cases (LBW), and population data were obtained from national statistics (year 2010), and DALYs came from the WHO (year 2004). The burden of disease due to SHS was calculated by multiplying the total burden of a specific health outcome (deaths or DALYs) by a population attributable fraction.

RESULTS

Using two estimates of SHS exposure in children: 48% and 60%, at least 12 and 14 deaths from LRI in children aged up to 2 years were attributed to SHS, for the two exposure scenarios, respectively. The highest burden of DALYs was for asthma in children aged up to 15 years: 2412, and 2970 DALYs, for the two exposure scenarios, respectively. For LRI, 419 and 500 DALYs, and for OM, 61 and 77 DALYs were attributed to SHS, for the two exposure scenarios, respectively. Between 13% and 27% of SIDS cases and between 3% and 16% of the cases of LBW at term were attributed to SHS exposure.

CONCLUSIONS

This study provides a conservative estimate of the public health impact of SHS exposure on Polish children. Lack of comprehensive, up to date health data concerning children, as well as lack of measures that would best reflect actual SHS exposure are major limitations of the study, likely to underestimate the burden of disease.

Impact of biomass fuels on pregnancy outcomes in central East India

BACKGROUND

Smoke from biomass burning has been linked to reduced birth weight; association with other birth outcomes is poorly understood. Our objective was to evaluate effects of exposure to biomass smoke on birth weight, preterm birth and stillbirth.

METHODS

Information on household cooking fuel was available for secondary analysis from two cohorts of pregnant women enrolled at delivery in India (n = 1744). Birth weight was measured and the modified Ballard performed to assess gestational age. Linear and logistic regression models were used to explore associations between fuel and birth outcomes. Effect sizes were adjusted in multivariate models for socio-demographic characteristics using propensity score techniques and for medical/obstetric covariates.

RESULTS

Compared to women who use gas (n = 265), women cooking with wood (n = 1306) delivered infants that were on average 112 grams lighter (95% CI -170.1, -54.6) and more likely to be preterm (OR 3.11, 95% CI 2.12, 4.59). Stillbirths were also more common in the wood group (4% versus 0%, p < 0.001). In adjusted models, the association between wood use and birth weight was no longer significant (14 g reduction; 95% CI -93, 66); however, the increased odds for preterm birth persisted (aOR 2.29; 95% CI 1.24, 4.21). Wood fuel use did not increase the risk of delivering either a low birth weight or small for gestational age infant.

CONCLUSIONS

The association between wood fuel use and reduced birth weight was insignificant in multivariate models using propensity score techniques to account for socio-demographic differences. In contrast, we demonstrated a persistent adverse impact of wood fuel use on preterm delivery. If prematurity is confirmed as a consequence of antenatal exposure to household air pollution, perinatal morbidity and mortality from household air pollution may be higher than previously appreciated.

If mothers had their say: research-informed intervention design for empowering mothers to establish smoke-free homes

The Empowering Mothers to Establish Smoke-free Homes (EMESH) project developed in response to an interdisciplinary health team seeking effective interventions for reducing/eliminating the environmental tobacco smoke exposure of infants with compromised respiratory status. Two study phases that informed the EMESH intervention design are described. Phase I involved semi-structured interviews with 20 caretakers of infants diagnosed with Bronchopulmonary Dysplasia (BPD). In Phase II, 75 randomly selected medical records of infants with BPD were reviewed to explore the family demographics and staff behavior regarding environmental tobacco smoke (ETS) interventions. Interview results suggest that families are open to partnering with social workers and interdisciplinary team members in addressing infants' ETS exposure, families' unique circumstances indicate a need for tailored interventions, and the use of self-efficacy and decisional balance tools are feasible options. Results from the medical records review indicate that many families are economically vulnerable and reside in regions where smoking is common. There is a paucity of staff documentation regarding ETS conversations and interventions, indicating that these conversations may not take place. Together these results suggest a two-pronged approach in the next phases of EMESH: staff training in hosting and documenting ETS conversations and a tailored, parent-driven set of intervention options.

Fetal abnormal growth associated with substance abuse

Substance abuse remains a major concern in pregnancy. The current review summarizes the best available literature on the subject. The findings of most studies are confounded by multiple drug use and environmental and social factors that by themselves are known to adversely affect the pregnancy outcomes of interest. Overall, however, substance abuse during pregnancy was associated with negative effects on birth weight and head circumference.

Pre-pregnancy Dietary Vitamin A Intake May Alleviate the Adverse Birth Outcomes Associated with Prenatal Pollutant Exposure: Epidemiologic Cohort Study in Poland

A cohort study assessed the relationship between dietary intake of vitamin A in 493 healthy mothers before and around conception and adverse birth outcomes associated with environmental toxicant exposures. The cohort, non-smoking women with singleton pregnancies, aged 18-35 years, gave birth at 34-43 weeks of gestation. The women were asked about their diets over one year preceding pregnancy. Measurements of PM2.5 were carried out during the second trimester. Birth outcomes were adjusted for potential confounding factors, including gestational age. Standardized beta regression coefficients confirmed an inverse association between PM2.5 and birth weight (beta = -172.4, p = 0.02), but the effect of vitamin A on birth weight was positive (beta = 176.05, p = 0.05), when the two were adjusted for each other. The negative effect of higher prenatal PM2.5 exposures (above third tertile) on birth weight was significant in women below the third tertile of vitamin A intakes (beta = -185.1, p = 0.00), but not in women with higher intakes (beta = 38.6, p = 0.61). The negative effect of higher PM2.5 exposure on length at birth was significant with lower vitamin A intakes (beta = -1.1, p = 0.00) but not with higher intakes (beta = -0.3, p = 0.56). Prepregnancy nutrition of mothers may modulate the harmful effects of prenatal exposures to pollutants on birth outcomes.

Effects of secondhand smoke on the birth weight of term infants and the demographic profile of Saudi exposed women

BACKGROUND

Maternal exposure to tobacco smoke during pregnancy is associated with detrimental effects on the mother and the fetus including; impaired fetal growth, low birth weight and preterm delivery. In utero exposure to tobacco is implicated in the etiology of many adults' diseases including obesity, diabetes and hypertension.The objectives of this study were to evaluate the effects of Secondhand Tobacco Smoke (SHS) exposure on newborns' anthropometric measurements and to compare the demographic profile of the women exposed to SHS to those who were not.

METHOD

This is a retrospective cohort study investigating the effects of SHS during pregnancy on newborns' anthropometry. Women who self-reported SHS exposure were compared with those not exposed. The primary outcomes were birth weight, newborn length and head circumference. Univariate analysis and multivariate regression analysis were performed. Adjusted differences with 95% confidence intervals were calculated.

RESULTS

Mothers exposed to SHS constituted 31% of the cohort. The mean birth weight of infants of exposed mothers was significantly lower by 35 g, 95% CI: 2-68 g, (P = 0.037) and the mean length was shorter by 0.261 cm, 95% CI 0.058-0.464 cm, (P = 0.012) compared to the infants of unexposed mothers. Women exposed to SHS, were younger, of lower parity and more likely to be illiterate than those who were not exposed in addition, exposed women were less likely to be primiparous.

CONCLUSION

The prevalence of exposure of Saudi pregnant women to SHS is high at 31% and it is associated with reduced birth weight, and shorter length of the newborn.

Effects of residential indoor air quality and household ventilation on preterm birth and term low birth weight in Los Angeles County, California

OBJECTIVES

The purpose of our study was to examine the effects of indoor residential air quality on preterm birth and term low birth weight (LBW).

METHODS

We evaluated 1761 nonsmoking women from a case-control survey of mothers who delivered a baby in 2003 in Los Angeles County, California. In multinomial logistic regression models adjusted for maternal age, education, race/ethnicity, parity and birthplace, we evaluated the effects of living with smokers or using personal or household products that may contain volatile organic compounds and examined the influence of household ventilation.

RESULTS

Compared with unexposed mothers, women exposed to secondhand smoke (SHS) at home had increased odds of term LBW (adjusted odds ratio [OR] = 1.36; 95% confidence interval [CI] =  0.85, 2.18) and preterm birth (adjusted OR = 1.27; 95% CI = 0.95, 1.70), although 95% CIs included the null. No increase in risk was observed for SHS-exposed mothers reporting moderate or high window ventilation. Associations were also observed for product usage, but only for women reporting low or no window ventilation.

CONCLUSIONS

Residential window ventilation may mitigate the effects of indoor air pollution among pregnant women in Los Angeles County, California.

Household air pollution and stillbirths in India: analysis of the DLHS-II National Survey

BACKGROUND

Several studies have linked biomass cooking fuel with adverse pregnancy outcomes such as preterm births, low birth weight and post-neonatal infant mortality, but very few have studied the associations with cooking fuel independent of other factors associated with stillbirths.

METHOD

We analyzed the data from 188,917 ever-married women aged 15-49 included in India's 2003-2004 District Level Household Survey-II to investigate the association between household use of cooking fuels (liquid petroleum gas/electricity, kerosene, biomass) and risk of stillbirth. Prevalence ratios (PRs) were obtained using Poisson regression with robust standard errors after controlling for several potentially confounding factors (socio-demographic and maternal health characteristics).

RESULTS

Risk factors significantly associated with occurrence of stillbirth in the Poisson regression with robust standard errors model were: literacy status of the mother and father, lighting fuel and cooking fuel used, gravida status, history of previous abortion, whether the woman had an antenatal check up, age at last pregnancy >35 years, labor complications, bleeding complications, fetal and other complications, prematurity and home delivery. After controlling the effect of these factors, women who cook with firewood (PR 1.24; 95% CI: 1.08-1.41, p=0.003) or kerosene (PR 1.36; 95% CI: 1.10-1.67, p=0.004) were more likely to have experienced a stillbirth than those who cook with LPG/electricity. Kerosene lamp use was also associated with stillbirths compared to electric lighting (PR 1.15; 95% CI: 1.06-1.25, p=0.001). The population attributable risk of firewood as cooking fuel for stillbirths in India was 11% and 1% for kerosene cooking.

CONCLUSION

Biomass and kerosene cooking fuels are associated with stillbirth occurrence in this population sample. Assuming these associations are causal, about 12% of stillbirths in India could be prevented by providing access to cleaner cooking fuel.

Pregnancy, smoking and birth outcomes

This review summarizes the epidemiology and consequences of maternal smoking in pregnancy, with emphasis on the adverse effects on birth outcomes. In developed countries, approximately 15%, and in developing countries, approximately 8% of women smoke cigarettes, and adolescents and women from lower socioeconomic groups are more likely than other women to smoke while pregnant. Maternal smoking during pregnancy is the largest modifiable risk factor for intrauterine growth restriction. A meta-analysis of recent studies showed that the pooled estimate for reduction of mean birthweight was 174 g (95% confidence limits 132-220 g). Other studies confirm a weaker association between maternal smoking and preterm birth. The population attributable risk of low birthweight due to maternal smoking in the UK is estimated to be 29-39%. Tobacco smoke toxins damage the placenta and may lead to placental abruption, abortion or placenta praevia. Infants of mothers who smoke in pregnancy are at an increased risk of respiratory complications including asthma, obesity and, possibly, behavioral disorders. These effects may be dose-related, as there is good evidence that mean birthweight decrements are greater with increased numbers of cigarettes smoked during pregnancy. Cotinine is a useful indicator of tobacco smoke exposure in pregnant women and higher levels in body fluids have been related to lower birthweights. Maternal genetic polymorphisms of the cytochrome P (CYP)450 and glutathione-S-transferase (GST) subfamilies of metabolic genes influence the magnitude of the effect of nicotine exposure on birth outcomes through their influence on nicotine metabolism. Greatly increased risk of cigarette smoke-induced diseases, including low birthweight, has been found in individuals with susceptible genotypes. Interventions to control maternal smoking are also considered.

Prenatal secondhand smoke exposure and infant birth weight in China

Epidemiologic evidence provides some support for a causal association between maternal secondhand smoke (SHS) exposure during pregnancy and reduction in infant birth weight. The purpose of this cross-sectional study is to examine the magnitude of this association in China, where both prevalence and dose of SHS exposure are thought to be higher than in U.S. populations. Women who gave birth in Beijing and Changchun September 2000–November 2001 were interviewed to quantify self-reported prenatal SHS exposure. Their medical records were reviewed for data on pregnancy complications and birth outcomes. Non-smoking women who delivered term babies (≥37 weeks gestation) were included in the study (N = 2,770). Nearly a quarter of the women (24%) reported daily SHS exposure, 47% reported no prenatal exposure, and 75% denied any SHS exposure from the husband smoking at home. Overall, no deficit in mean birth weight was observed with exposure from all sources of SHS combined (+11 grams, 95% CI: +2, +21). Infants had higher mean birth weights among the exposed than the unexposed for all measures of SHS exposure. Future studies on SHS exposure and infant birth weight in China should emphasize more objective measures of exposure to quantify and account for any exposure misclassification.

Exploring the reach and program use of Hello World, an email-based health promotion program for pregnant women in the Netherlands

Background

In 2006, the Dutch government initiated Hello World, an email-based program promoting healthy lifestyles among pregnant women through quizzes with pregnancy-related questions. In 2008, an updated version was released.

The present study aimed to (1) examine the reach of Hello World and the representativeness of its users for all pregnant women in the Netherlands, (2) explore the relationship between program engagement and lifestyle characteristics, and (3) explore the relationship between the program content participants accessed (content on smoking, physical activity, and nutrition) and their lifestyle characteristics.

Methods

Data from 4,363 pregnant women were included. After registration, women received an online questionnaire with demographic and lifestyle questions. To evaluate their representativeness, their demographic characteristics were compared with existing data for Dutch (pregnant) women. Women were classified on the following lifestyle characteristics: smoking, nutrition, physical activity, and pre-pregnancy weight status. Program use was tracked and the relationships between lifestyle characteristics, program engagement, and the percentage of smoking, physical activity, and nutrition questions accessed after opening a quiz were explored using Mann–Whitney U tests and Kruskal-Wallis tests.

Results

Hello World reached ±4% of its target population. Ten percent of participants were low educated and 22% immigrants. On average, women received 6.1 (SD:2.8) quiz emails and opened 32% of the associated quizzes (2.0, SD:2.1). A significant positive association was found between the number of quizzes opened and the number of healthy lifestyle characteristics. After opening a quiz, women accessed most smoking, nutrition, and physical activity questions. Significant relationships were found between several lifestyle characteristics and the percentage of smoking, physical activity, and nutrition questions accessed. However, between-group differences were small, quiz topics were largely unrelated to their lifestyle characteristics, and inconsistencies were found regarding the directions of these associations.

Conclusions

Hello World reached ±4% of its target population, which is lower than the reach of its previous version (±8%). Relatively few low educated and immigrant women registered for the program. Active participation in the program was positively associated with the number of healthy behaviours participants engaged in. The program content participants chose to access was largely unrelated to their lifestyle characteristics.

Particulate matter exposure during pregnancy is associated with birth weight, but not gestational age, 1962-1992: a cohort study

BACKGROUND

Exposure to air pollutants is suggested to adversely affect fetal growth, but the evidence remains inconsistent in relation to specific outcomes and exposure windows.

METHODS

Using birth records from the two major maternity hospitals in Newcastle upon Tyne in northern England between 1961 and 1992, we constructed a database of all births to mothers resident within the city. Weekly black smoke exposure levels from routine data recorded at 20 air pollution monitoring stations were obtained and individual exposures were estimated via a two-stage modeling strategy, incorporating temporally and spatially varying covariates. Regression analyses, including 88,679 births, assessed potential associations between exposure to black smoke and birth weight, gestational age and birth weight standardized for gestational age and sex.

RESULTS

Significant associations were seen between black smoke and both standardized and unstandardized birth weight, but not for gestational age when adjusted for potential confounders. Not all associations were linear. For an increase in whole pregnancy black smoke exposure, from the 1(st) (7.4 μg/m(3)) to the 25(th) (17.2 μg/m(3)), 50(th) (33.8 μg/m(3)), 75(th) (108.3 μg/m(3)), and 90(th) (180.8 μg/m(3)) percentiles, the adjusted estimated decreases in birth weight were 33 g (SE 1.05), 62 g (1.63), 98 g (2.26) and 109 g (2.44) respectively. A significant interaction was observed between socio-economic deprivation and black smoke on both standardized and unstandardized birth weight with increasing effects of black smoke in reducing birth weight seen with increasing socio-economic disadvantage.

CONCLUSIONS

The findings of this study progress the hypothesis that the association between black smoke and birth weight may be mediated through intrauterine growth restriction. The associations between black smoke and birth weight were of the same order of magnitude as those reported for passive smoking. These findings add to the growing evidence of the harmful effects of air pollution on birth outcomes.

Maternal exposure to air pollution before and during pregnancy related to changes in newborn's cord blood lymphocyte subpopulations. The EDEN study cohort

Background

Toxicants can cross the placenta and expose the developing fetus to chemical contamination leading to possible adverse health effects, by potentially inducing alterations in immune competence. Our aim was to investigate the impacts of maternal exposure to air pollution before and during pregnancy on newborn's immune system.

Methods

Exposure to background particulate matter less than 10 μm in diameter (PM₁₀) and nitrogen dioxide (NO₂) was assessed in 370 women three months before and during pregnancy using monitoring stations. Personal exposure to four volatile organic compounds (VOCs) was measured in a subsample of 56 non-smoking women with a diffusive air sampler during the second trimester of pregnancy. Cord blood was analyzed at birth by multi-parameter flow cytometry to determine lymphocyte subsets.

Results

Among other immunophenotypic changes in cord blood, decreases in the CD4+CD25+ T-cell percentage of 0.82% (p = 0.01), 0.71% (p = 0.04), 0.88% (p = 0.02), and 0.59% (p = 0.04) for a 10 μg/m³ increase in PM₁₀ levels three months before and during the first, second and third trimester of pregnancy, respectively, were observed after adjusting for confounders. A similar decrease in CD4+CD25+ T-cell percentage was observed in association with personal exposure to benzene. A similar trend was observed between NO₂ exposure and CD4+CD25+ T-cell percentage; however the association was stronger between NO₂ exposure and an increased percentage of CD8+ T-cells.

Conclusions

These data suggest that maternal exposure to air pollution before and during pregnancy may alter the immune competence in offspring thus increasing the child's risk of developing health conditions later in life, including asthma and allergies.