Bianca Cox

Effect of smoke-free legislation on perinatal and child health: a systematic review and meta-analysis

BACKGROUND Smoke-free legislation has the potential to reduce the substantive disease burden associated with second-hand smoke exposure, particularly in children. We investigated the effect of smoke-free legislation on perinatal and child health. METHODS We searched 14 online databases from January, 1975 to May, 2013, with no language restrictions, for published studies, and the WHO International Clinical Trials Registry Platform for unpublished studies. Citations and reference lists of articles of interest were screened and an international expert panel was contacted to identify additional studies. We included studies undertaken with designs approved by the Cochrane Effective Practice and Organisation of Care that reported associations between smoking bans in workplaces, public places, or both, and one or more predefined early-life health indicator. The primary outcomes were preterm birth, low birthweight, and hospital attendances for asthma. Effect estimates were pooled with random-effects meta-analysis. This study is registered with PROSPERO, number CRD42013003522. FINDINGS We identified 11 eligible studies (published 2008-13), involving more than 2·5 million births and 247,168 asthma exacerbations. All studies used interrupted time-series designs. Five North American studies described local bans and six European studies described national bans. Risk of bias was high for one study, moderate for six studies, and low for four studies. Smoke-free legislation was associated with reductions in preterm birth (four studies, 1,366,862 individuals; -10·4% [95% CI -18·8 to -2·0]; p=0·016) and hospital attendances for asthma (three studies, 225,753 events: -10·1% [95% CI -15·2 to -5·0]; p=0·0001). No significant effect on low birthweight was identified (six studies, >1·9 million individuals: -1·7% [95% CI -5·1 to 1·6]; p=0·31). INTERPRETATION Smoke-free legislation is associated with substantial reductions in preterm births and hospital attendance for asthma. Together with the health benefits in adults, this study provides strong support for WHO recommendations to create smoke-free environments. FUNDING Thrasher Fund, Lung Foundation Netherlands, International Paediatric Research Foundation, Maastricht University, Commonwealth Fund.

Effect of smoke-free legislation on perinatal and child

BACKGROUND Smoke-free legislation has the potential to reduce the substantive disease burden associated with second-hand smoke exposure, particularly in children. We investigated the effect of smoke-free legislation on perinatal and child health. METHODS We searched 14 online databases from January, 1975 to May, 2013, with no language restrictions, for published studies, and the WHO International Clinical Trials Registry Platform for unpublished studies. Citations and reference lists of articles of interest were screened and an international expert panel was contacted to identify additional studies. We included studies undertaken with designs approved by the Cochrane Effective Practice and Organisation of Care that reported associations between smoking bans in workplaces, public places, or both, and one or more predefined early-life health indicator. The primary outcomes were preterm birth, low birthweight, and hospital attendances for asthma. Effect estimates were pooled with random-effects meta-analysis. This study is registered with PROSPERO, number CRD42013003522. FINDINGS We identified 11 eligible studies (published 2008-13), involving more than 2·5 million births and 247,168 asthma exacerbations. All studies used interrupted time-series designs. Five North American studies described local bans and six European studies described national bans. Risk of bias was high for one study, moderate for six studies, and low for four studies. Smoke-free legislation was associated with reductions in preterm birth (four studies, 1,366,862 individuals; -10·4% [95% CI -18·8 to -2·0]; p=0·016) and hospital attendances for asthma (three studies, 225,753 events: -10·1% [95% CI -15·2 to -5·0]; p=0·0001). No significant effect on low birthweight was identified (six studies, >1·9 million individuals: -1·7% [95% CI -5·1 to 1·6]; p=0·31). INTERPRETATION Smoke-free legislation is associated with substantial reductions in preterm births and hospital attendance for asthma. Together with the health benefits in adults, this study provides strong support for WHO recommendations to create smoke-free environments. FUNDING Thrasher Fund, Lung Foundation Netherlands, International Paediatric Research Foundation, Maastricht University, Commonwealth Fund.

An epidemiological appraisal of the association between heart rate variability and particulate air pollution: a meta-analysis

Objective Studies on the association between short-term exposure to ambient air pollution and heart rate variability (HRV) suggest that particulate matter (PM) exposure is associated with reductions in measures of HRV, but there is heterogeneity in the nature and magnitude of this association between studies. The authors performed a meta-analysis to determine how consistent this association is. Data source The authors searched the Pubmed citation database and Web of Knowledge to identify studies on HRV and PM. Study selection Of the epidemiologic studies reviewed, 29 provided sufficient details to be considered. The meta-analysis included 18667 subjects recruited from the population in surveys, studies from patient groups, and from occupationally exposed groups. Data extraction Two investigators read all papers and computerised all relevant information. Results The authors computed pooled estimates from a random-effects model. In the combined studies, an increase of 10 μg/m3 in PM2.5 was associated with significant reductions in the time-domain measurements, including low frequency (−1.66%, 95% CI −2.58% to −0.74%) and high frequency (−2.44%, 95% CI −3.76% to −1.12%) and in frequency-domain measurements, for SDNN (−0.12%, 95% CI −0.22% to −0.03%) and for rMSSD (−2.18%, 95% CI −3.33% to −1.03%). Funnel plots suggested that no publication bias was present and a sensitivity analysis confirmed the robustness of our combined estimates. Conclusion The meta-analysis supports an inverse relationship between HRV, a marker for a worse cardiovascular prognosis, and particulate air pollution.

Placental Mitochondrial DNA Content and Particulate Air Pollution during in Utero Life

Background: Studies emphasize the importance of particulate matter (PM) in the formation of reactive oxygen species and inflammation. We hypothesized that these processes can influence mitochondrial function of the placenta and fetus. Objective: We investigated the influence of PM10 exposure during pregnancy on the mitochondrial DNA content (mtDNA content) of the placenta and umbilical cord blood. Methods: DNA was extracted from placental tissue (n = 174) and umbilical cord leukocytes (n = 176). Relative mtDNA copy numbers (i.e., mtDNA content) were determined by real-time polymerase chain reaction. Multiple regression models were used to link mtDNA content and in utero exposure to PM10 over various time windows during pregnancy. Results: In multivariate-adjusted analysis, a 10-µg/m³ increase in PM10 exposure during the last month of pregnancy was associated with a 16.1% decrease [95% confidence interval (CI): –25.2, –6.0%, p = 0.003] in placental mtDNA content. The corresponding effect size for average PM10 exposure during the third trimester was 17.4% (95% CI: –31.8, –0.1%, p = 0.05). Furthermore, we found that each doubling in residential distance to major roads was associated with an increase in placental mtDNA content of 4.0% (95% CI: 0.4, 7.8%, p = 0.03). No association was found between cord blood mtDNA content and PM10 exposure. Conclusions: Prenatal PM10 exposure was associated with placental mitochondrial alterations, which may both reflect and intensify oxidative stress production. The potential health consequences of decreased placental mtDNA content in early life must be further elucidated.

Impact of a stepwise introduction of smoke-free legislation on the rate of preterm births: analysis of routinely collected birth data

Objective To investigate the incidence of preterm delivery in the Belgian population after implementation of smoke-free legislation in three phases (in public places and most workplaces January 2006, in restaurants January 2007, and in bars serving food January 2010). Design Logistic regression analyses on routinely collected birth data from January 2002 to December 2011. Setting Flanders, Belgium. Population All live born singleton births delivered at 24–44 weeks of gestation (n=606 877, with n=448 520 spontaneous deliveries). Main outcome measures Preterm birth (gestational age <37 weeks). Results We found reductions in the risk of preterm birth after the introduction of each phase of the smoking ban. No decreasing trend was evident in the years or months before the bans. We observed a step change in the risk of spontaneous preterm delivery of −3.13% (95% CI −4.37% to −1.87%; P<0.01) on 1 January 2007 (ban on smoking in restaurants), and an annual slope change of −2.65% (−5.11% to −0.13%; P=0.04) after 1 January 2010 (ban on smoking in bars serving food). The analysis for all births gave similar results: a step change of −3.18% (−5.38% to −0.94%; P<0.01) on 1 January 2007, and an annual slope change of −3.50% (−6.35% to −0.57%; P=0.02) after 1 January 2010. These changes could not be explained by personal factors (infant sex, maternal age, parity, socioeconomic status, national origin, level of urbanisation); time related factors (underlying trends, month of the year, day of the week); or population related factors (public holidays, influenza epidemics, and short term changes in apparent temperature and particulate air pollution). Conclusion Our study shows a consistent pattern of reduction in the risk of preterm delivery with successive population interventions to restrict smoking. This finding is not definitive but it supports the notion that smoking bans have public health benefits from early life.

Socioeconomic inequalities in lung cancer mortality in 16 European populations

OBJECTIVES This paper aims to describe socioeconomic inequalities in lung cancer mortality in Europe and to get further insight into socioeconomic inequalities in lung cancer mortality in different European populations by relating these to socioeconomic inequalities in overall mortality and smoking within the same or reference populations. Particular attention is paid to inequalities in Eastern European and Baltic countries. METHODS Data were obtained from mortality registers, population censuses and health interview surveys in 16 European populations. Educational inequalities in lung cancer and total mortality were assessed by direct standardization and calculation of two indices of inequality: the Relative Index of Inequality (RII) and the Slope Index of Inequality (SII). SIIs were used to calculate the contribution of inequalities in lung cancer mortality to inequalities in total mortality. Indices of inequality in lung cancer mortality in the age group 40-59 years were compared with indices of inequalities in smoking taking into account a time lag of 20 years. RESULTS The pattern of inequalities in Eastern European and Baltic countries is more or less similar as the one observed in the Northern countries. Among men educational inequalities are largest in the Eastern European and Baltic countries. Among women they are largest in Northern European countries. Whereas among Southern European women lung cancer mortality rates are still higher among the high educated, we observe a negative association between smoking and education among young female adults. The contribution of lung cancer mortality inequalities to total mortality inequalities is in most male populations more than 10%. Important smoking inequalities are observed among young adults in all populations. In Sweden, Hungary and the Czech Republic smoking inequalities among young adult women are larger than lung cancer mortality inequalities among women aged 20 years older. CONCLUSIONS Important socioeconomic inequalities exist in lung cancer mortality in Europe. They are consistent with the geographical spread of the smoking epidemic. In the next decades socioeconomic inequalities in lung cancer mortality are likely to persist and even increase among women. In Southern European countries we may expect a reversal from a positive to a negative association between socioeconomic status and lung cancer mortality. Continuous efforts are necessary to tackle socioeconomic inequalities in lung cancer mortality in all European countries.

The reliability of the Minimum European Health Module.

Objectives:The Minimum European Health Module (MEHM) consists of 3 global questions concerning 3 health domains: self-perceived health, chronic conditions and long-term activity limitation. The objective of this paper is to evaluate the reliability of the MEHM.Methods:Participants of the Belgian Food Consumption Survey were interviewed twice: 170 individuals were selected for the MEHM reliability evaluation. For each of the 3 questions Pearson and Kappa coefficients were estimated. Analyses were stratified by gender, age, education, language and time between the interviews.Results:The Pearson correlations are between 0.73 and 0.81. The Kappa estimates are good or excellent: 0.74 (self-perceived health), 0.77 (chronic conditions) and 0.68 (activity limitation). Also stratified analyses indicated in general an acceptable reliability.Conclusion:The MEHM has an acceptable reliability.

Validity of parent-reported weight and height of preschool children measured at home or estimated without home measurement: a validation study

BackgroundParental reports are often used in large-scale surveys to assess childrens body mass index (BMI). Therefore, it is important to know to what extent these parental reports are valid and whether it makes a difference if the parents measured their childrens weight and height at home or whether they simply estimated these values. The aim of this study is to compare the validity of parent-reported height, weight and BMI values of preschool children (3-7 y-old), when measured at home or estimated by parents without actual measurement.MethodsThe subjects were 297 Belgian preschool children (52.9% male). Participation rate was 73%. A questionnaire including questions about height and weight of the children was completed by the parents. Nurses measured height and weight following standardised procedures. International age- and sex-specific BMI cut-off values were employed to determine categories of weight status and obesity.ResultsOn the group level, no important differences in accuracy of reported height, weight and BMI were identified between parent-measured or estimated values. However, for all 3 parameters, the correlations between parental reports and nurse measurements were higher in the group of children whose body dimensions were measured by the parents. Sensitivity for underweight and overweight/obesity were respectively 73% and 47% when parents measured their childs height and weight, and 55% and 47% when parents estimated values without measurement. Specificity for underweight and overweight/obesity were respectively 82% and 97% when parents measured the children, and 75% and 93% with parent estimations.ConclusionsDiagnostic measures were more accurate when parents measured their childs weight and height at home than when those dimensions were based on parental judgements. When parent-reported data on an individual level is used, the accuracy could be improved by encouraging the parents to measure weight and height of their children at home.

In Utero Fine Particle Air Pollution and Placental Expression of Genes in the Brain-Derived Neurotrophic Factor Signaling Pathway: An ENVIRONAGE Birth Cohort Study.

Background Developmental processes in the placenta and the fetal brain are shaped by the same biological signals. Recent evidence suggests that adaptive responses of the placenta to the maternal environment may influence central nervous system development. Objectives We studied the association between in utero exposure to fine particle air pollution with a diameter ≤ 2.5 μm (PM2.5) and placental expression of genes implicated in neural development. Methods Expression of 10 target genes in the brain-derived neurotrophic factor (BDNF) signaling pathway were quantified in placental tissue of 90 mother–infant pairs from the ENVIRONAGE birth cohort using quantitative real-time polymerase chain reaction. Trimester-specific PM2.5 exposure levels were estimated for each mother’s home address using a spatiotemporal model. Mixed-effects models were used to evaluate the association between the target genes and PM2.5 exposure measured in different time windows of pregnancy. Results A 5-μg/m3 increase in residential PM2.5 exposure during the first trimester of pregnancy was associated with a 15.9% decrease [95% confidence interval (CI): –28.7, –3.2%, p = 0.015] in expression of placental BDNF at birth. The corresponding estimate for synapsin 1 (SYN1) was a 24.3% decrease (95% CI: –42.8, –5.8%, p = 0.011). Conclusions Placental expression of BDNF and SYN1, two genes implicated in normal neurodevelopmental trajectories, decreased with increasing in utero exposure to PM2.5. Future studies are needed to confirm our findings and evaluate the potential relevance of associations between PM2.5 and placental expression of BDNF and SYN1 on neurodevelopment. We provide the first molecular epidemiological evidence concerning associations between in utero fine particle air pollution exposure and the expression of genes that may influence neurodevelopmental processes. Citation Saenen ND, Plusquin M, Bijnens E, Janssen BG, Gyselaers W, Cox B, Fierens F, Molenberghs G, Penders J, Vrijens K, De Boever P, Nawrot TS. 2015. In utero fine particle air pollution and placental expression of genes in the brain-derived neurotrophic factor signaling pathway: an ENVIRONAGE Birth Cohort Study. Environ Health Perspect 123:834–840; http://dx.doi.org/10.1289/ehp.1408549

Human exposure to endocrine, disrupting chemicals and fertility: a case-control study in male subfertility patients

BACKGROUND Dioxins, PCBs, chlorinated pesticides, brominated flame retardants, bisphenol A, triclosan, perfluorinated compounds and phthalates are known as endocrine disrupting chemicals (EDCs). OBJECTIVES The aim of our study was to investigate whether higher exposure to EDCs is associated with increased subfertility in men. METHODS We measured biomarkers of exposure in 163 men, recruited through four fertility clinics. According to WHO guidelines, we used a total motility count (TMC) of 20 million as cut-off value. We assigned patients to the case group when two semen samples - collected at least one week apart - had a TMC<20 and to the control group when both samples had a TMC≥20. To estimate the risk of subfertility and alteration in sex hormone concentrations we used multivariable-adjusted analysis, using logistic and linear regressions, respectively. RESULTS For an IQR increase in serum oxychlordane, the odds ratio for subfertility was 1.98 (95% CI: 1.07; 3.69). Furthermore, men with serum levels of BDE209 above the quantification limit had an odds of 7.22 (1.03; 50.6) for subfertility compared with those having values below the LOQ. Urinary levels of phthalates and triclosan were negatively associated with inhibin B and positively with LH. Urinary bisphenol A correlated negatively with testosterone levels. CONCLUSIONS Our study in men showed that internal body concentrations of endocrine disrupting chemicals are associated with an increased risk of subfertility together with alterations in hormone levels. The results emphasize the importance to reduce chemicals in the environment in order to safeguard male fertility.