The influence of organochlorine compound exposure on the physiological development of children

The present study summarizes the advances on the knowledge of the health disturbances associated to fetal exposure to organochlorine compounds in a cohort of children from Menorca. Higher incidence of diverse deleterious health effects at 4 years of age have been observed, e.g. hexachlorobenzene (HCB) and poor social behavior and attention-deficit hyperactivity disorder, 4,4’-DDE and asthma, wheeze, lower respiratory tract infections and alteration of urinary coproporphyrins, HCB, ß-hexachlorocyclohexane and 4,4’-DDE and alteration of thyroid hormones, HCB, 4,4’-DDE and polychlorobiphenyls (PCBs) and overweight, 4,4’-DDT and PCBs and lower neurodevelopment. A protective effect of breastfeeding against decreases of cognitive skills in children due to 4,4’-DDT exposure has also been documented. This protective effect shows that other factors besides pollutant exposure and genetic variability influence on the health effects of environmental pollutants into human populations. These results are important for the understanding of the health implications of exposome studies.Aquest estudi resumeix els avenços en el coneixement dels trastorns de salut associats a l’exposició fetal a compostos organoclorats en una cohort de nens de Menorca. S’ha observat una incidència major de diversos efectes perjudicials per la salut als 4 anys d’edat, per exemple, hexaclorobenzè (HCB) i comportament social pobre i trastorn per dèficit d’atenció amb hiperactivitat, 4,4’- DDE i asma, xiulets pulmonars, infeccions de les vies respiratòries baixes i alteració de coproporfirines urinàries, HCB, ß-hexaclorociclohexà i 4,4’-DDE i alteració de les hormones tiroïdals, HCB, 4,4’-DDE i policlorobifenils (PCBs) i sobrepès, 4,4’-DDT i PCBs i menor desenvolupament neurològic. També s’ha documentat un efecte protector de la lactància materna contra la disminució de les habilitats cognitives dels nens a causa de l’exposició a 4,4’-DDT. Aquest efecte protector mostra que altres factors, a més de l’exposició a contaminants i genètica personal, influeixen en els efectes de salut dels contaminants ambientals en les poblacions humanes. Aquests resultats són importants per comprendre les implicacions per la salut dels estudis d’exposomes

Effectiveness of a complex intervention in reducing the prevalence of smoking among adolescents: study design of a cluster-randomized controlled trial

BACKGROUND: The likelihood of an adolescent taking up smoking may be influenced by his or her society, school and family. Thus, changes in the immediate environment may alter a young person’s perception of smoking. METHODS/DESIGN: The proposed multi-center, cluster-randomized controlled trial will be stratified by the baseline prevalence of smoking in schools. Municipalities with fewer than 100,000 inhabitants will be randomly assigned to a control or intervention group. One secondary school will be randomly selected from each municipality. These schools will be randomized to two groups: the students of one will receive any existing educational course regarding smoking, while those of the other school will receive a four-year, class-based curriculum intervention (22 classroom lessons) aimed at reinforcing a smoke-free school policy and encouraging smoking cessation in parents, pupils, and teachers. The intervention will also include annual meetings with parents and efforts to empower adolescents to change the smoking-related attitudes and behaviors in their homes, classrooms and communities. We will enroll children aged 12-13 years as they enter secondary school during two consecutive school years (to obtain sufficient enrolled subjects). We will follow them for five years, until two years after they leave secondary school. All external evaluators and analysts will be blinded to school allocation. The aim of this study is to analyze the effectiveness of a complex intervention in reducing the prevalence of smoking in the third year of compulsory secondary education (ESO) and two years after secondary school, when the participants are 14-15 and 17-18 years old, respectively. DISCUSSION: Most interventions aimed at preventing smoking among adolescents yield little to no positive long-term effects. This clinical trial will analyze the effectiveness of a complex intervention aimed at reducing the incidence and prevalence of smoking in this vulnerable age group. TRIAL REGISTRATION: Current Controlled Trials: NCT01602796

Temporal trends in concentrations and total serum burdens of organochlorine compounds from birth until adolescence and the role of breastfeeding

Introduction: The aims of the present study are to assess the temporal trends of organochlorine compounds (OCs) concentrations and total serum burdens from birth until adolescence and the influence of breastfeeding in these temporal trends. Methods: In 1997 two birth cohort studies were set up in Ribera d'Ebre (N=102) and the island of Menorca (N=482), Spain. Concentrations (ng/mL) of OCs [pentachlorobenzene (PeCB), four isomers of hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (4,4'-DDT), dichlorodiphenyldichloroethylene (4,4'-DDE) and seven polychlorobiphenyl congeners (σ7PCBs)] were measured in cord blood and at the age of 4 and 14years. The total serum burdens (ng) of these compounds were estimated based on the total blood volume (mL) of children at the different ages. We compared median concentrations and total serum burdens of these OCs at the different time-points of follow-up between children of Ribera d'Ebre and Menorca and between breastfed and non-breastfed children. Results: From birth until adolescence concentrations of all OCs drastically reduced. These reductions were mainly derived from the dilution of OCs, associated to an increase in total blood volume of children at the age of 4 and 14years. Despite the reduction in OCs concentrations, the total serum burdens of 4,4'-DDE and σ7PCBs, were higher in adolescents than at birth. Increases in OCs total serum burden occurred both in breastfed and non-breastfed children, but were significantly higher in the first. Conclusions: Even after decades of banning OCs production and use, current young generations in westernized countries are still bioaccumulating these compounds. Given the potential health effects of OCs, especial attention should be paid in the control of secondary emissions in the environment and in the control of food production and contamination. In countries with endemic malaria it is important to work towards effective alternatives to the use of DDT. © 2014 Elsevier Ltd.This study was supported by grants from the Spanish Ministry of Health (FIS-97/1102, FIS 97/0588, 00/0021-2, PI061756, PS0901958 and FIS PS09/00362), the Instituto de Salud Carlos III (Red INMA G03/176 and CB06/02/0041), Fundació La Caixa (97/009-00 and 00/077-00), and the Generalitat de Catalunya-CIRIT 1999SGR 00241. Finally, the authors would like to be grateful to the families in Flix and Menorca participating in the study, to the high school management team of Flix for their interest and collaboration, and to Rosa Maria Sabaté, the nurse of the health center of Flix, for her support and commitment.Peer reviewe

Exposure to Hexachlorobenzene during Pregnancy and Children’s Social Behavior at 4 Years of Age

BACKGROUND: Hexachlorobenzene (HCB) is an organochlorine chemical that has been used in agriculture and industrial processes. Behavioral impairment after HCB exposure has been described in animal models, but little information is available in humans. OBJECTIVES: Our goal was to study the association of prenatal exposure to HCB with the social behavior of preschool children. METHODS: Two birth cohorts in Ribera d’Ebre and Menorca (Spain) were set up between 1997 and 1999 (n = 475). The California Preschool Social Competence Scale and the Attention-Deficit Hyperactivity Disorder (ADHD) were scored by each 4-year-old child’s teacher. Organochlorine compounds were measured in cord serum. Children’s diet and parental sociodemographic information were obtained through questionnaire. RESULTS: Children with concentrations of HCB > 1.5 ng/mL at birth had a statistically significant increased risk of having poor Social Competence [relative risk (RR) = 4.04; 95% confidence interval (CI), 1.76–9.58] and ADHD (RR = 2.71; 95% CI, 1.05–6.96) scores. No association was found between HCB and the cognitive and psychomotor performance of these children. CONCLUSIONS: Prenatal exposure to current concentrations of HCB in Spain is associated with a decrease in the behavioral competence at preschool ages. These results should be considered when evaluating the potential neurotoxicologic effects of HCB

Prenatal Concentrations of Polychlorinated Biphenyls, DDE, and DDT and Overweight in Children: A Prospective Birth Cohort Study

Background: Recent experimental evidence suggests that prenatal exposure to endocrine-disrupting chemicals (EDCs) may increase postnatal obesity risk and that these effects may be sex or diet dependent

Prenatal Dichlorodiphenyldichloroethylene (DDE) and Asthma in Children

Prevalence of asthma increases with increasing dichlorodiphenyldichloroethylene (DDE) levels. However, the effect of early-life exposure, the fundamental window of exposure, is unknown. We assessed the association between prenatal DDE and other organochlorine compounds, and atopy and asthma during infancy. All women presenting for antenatal care in Menorca (Spain) over 12 months starting in mid-1997 were invited to take part in a longitudinal study; 482 children were subsequently enrolled, and 468 (97.1%) provided complete outcome data up to the fourth year of study. Prenatal exposure of organochlorine compounds was measured in cord serum in 405 (83%) children. Asthma was defined on the basis of wheezing at 4 years of age, persistent wheezing, or doctor-diagnosed asthma. We measured specific immunoglobulin-E (IgE) against house dust mite, cat, and grass in sera extracted at 4 years of age. DDE (median = 1.03 ng/mL) was detected in all children, as well as hexachlorobenzene (0.68 ng/mL) and polychlorobiphenyls (0.69 ng/mL). Wheezing at 4 years of age increased with DDE concentration, particularly at the highest quartile [9% in the lowest quartile (< 0.57 ng/mL) vs. 19% in the highest quartile (1.90 ng/mL); relative risk = 2.63 (95% confidence interval 1.19–4.69), adjusting for maternal asthma, breast-feeding, education, social class, or other organochlorines]. The association was not modified by IgE sensitization and occurred with the same strength among nonatopic subjects and among those with persistent wheezing or diagnosed asthma. DDE was not associated with atopy alone. Prenatal exposure to DDE residues may contribute to development of asthma

Decay resistance variability of European wood species thermally modified by industrial process

Thermal modification is now considered as a new ecofriendly industrial wood modification process improving mainly the material decay resistance and its dimensional stability. Most industrial thermal treatment processes use convection heat transfer which induces sometimes heterogeneous treatment temperature propagation within the oven and lead to the heterogeneity in treatment efficiency. Thus, it is common that treatment is not completely effective on several stack boards, in a same batch. The aim of this paper was to study the decay resistance variability of various European wood species thermally modified. Thermal modifications were performed around 240°C during 4h, on about 10 m3 of 27 x 152 x 2000 mm3 wood planks placed in an industrial oven having a volume of 20 m3, on the following wood species: spruce, ash, beech and poplar. All of the tests concerning the decay resistance were carried out in the laboratory using untreated beech and pine woods as reference materials. An agar block test was used to determine the resistance of thermally modified woods, leached beforehand according to EN 84 standard or not, to brown-rot and white-rot fungi, according to XP CEN/TS 15083-1. A large selection of treated wood samples was tested in order to estimate the variability of treatment efficiency. Thermal treatment increased the biological durability of all leached and un-leached modified wood samples, compared with native wood species. The treatment temperature of 240°C used in this study is sufficient to reach durability classes ''durable'' or ''very durable'' for the four wood species. However, the dispersion of weight loss values, due to the fungal attacks was very important and showed a large variability of the durability of wood which has been treated in a single batch. These results showed that there is a substantial need to develop process control and² indicator in order to insure that the quality of treated timber is properly evaluated with a view to putting this modified timber on the market under a chain of custody. (Résumé d'auteur

A pandemic treaty for equitable global access to medical countermeasures:seven recommendations for sharing intellectual property, know-how and technology Comment

The COVID-19 pandemic highlighted how current international laws and practices fail to ensure medical countermeasures (ie, vaccines, therapeutics, diagnostics and personal protective equipment) are equitably distributed in a global health crisis. In 2021, the 194 Member States of the World Health Organization agreed to begin negotiations towards an international instrument that would better position the world to prevent, respond and prepare for future pandemics (often called a ‘pandemic treaty’.) A pandemic treaty presents an opportunity to address these challenges in international law, and craft a better system, based on solidarity, for the global development and distribution of medical countermeasures. We recommend that a pandemic treaty ensures sufficient financing for biomedical research and development (R&D), creates conditions for licensing government-funded R&D, mandates technology transfer, shares intellectual property, data and knowledge needed for the production and supply of products, and streamlines regulatory standards and procedures to market medical countermeasures. We also recommend that a pandemic treaty ensures greater transparency and inclusive governance of these systems. The aim of these components in a pandemic treaty should be to craft a better collective response to global health threats, consistent with existing international law, political commitments and sound public health practice

Spatial and temporal variability of personal environmental exposure to radio frequency electromagnetic fields in children in Europe

Exposure to radiofrequency electromagnetic fields (RF-EMF) has rapidly increased and little is known about exposure levels in children. This study describes personal RF-EMF environmental exposure levels from handheld devices and fixed site transmitters in European children, the determinants of this, and the day-to-day and year-to-year repeatability of these exposure levels.; Personal environmental RF-EMF exposure (μW/m; 2; , power flux density) was measured in 529 children (ages 8-18 years) in Denmark, the Netherlands, Slovenia, Switzerland, and Spain using personal portable exposure meters for a period of up to three days between 2014 and 2016, and repeated in a subsample of 28 children one year later. The meters captured 16 frequency bands every 4 s and incorporated a GPS. Activity diaries and questionnaires were used to collect children's location, use of handheld devices, and presence of indoor RF-EMF sources. Six general frequency bands were defined: total, digital enhanced cordless telecommunications (DECT), television and radio antennas (broadcast), mobile phones (uplink), mobile phone base stations (downlink), and Wireless Fidelity (WiFi). We used adjusted mixed effects models with region random effects to estimate associations of handheld device use habits and indoor RF-EMF sources with personal RF-EMF exposure. Day-to-day and year-to-year repeatability of personal RF-EMF exposure were calculated through intraclass correlations (ICC).; Median total personal RF-EMF exposure was 75.5 μW/m; 2; . Downlink was the largest contributor to total exposure (median: 27.2 μW/m; 2; ) followed by broadcast (9.9 μW/m; 2; ). Exposure from uplink (4.7 μW/m; 2; ) was lower. WiFi and DECT contributed very little to exposure levels. Exposure was higher during day (94.2 μW/m; 2; ) than night (23.0 μW/m; 2; ), and slightly higher during weekends than weekdays, although varying across regions. Median exposures were highest while children were outside (157.0 μW/m; 2; ) or traveling (171.3 μW/m; 2; ), and much lower at home (33.0 μW/m; 2; ) or in school (35.1 μW/m; 2; ). Children living in urban environments had higher exposure than children in rural environments. Older children and users of mobile phones had higher uplink exposure but not total exposure, compared to younger children and those that did not use mobile phones. Day-to-day repeatability was moderate to high for most of the general frequency bands (ICCs between 0.43 and 0.85), as well as for total, broadcast, and downlink for the year-to-year repeatability (ICCs between 0.49 and 0.80) in a small subsample.; The largest contributors to total personal environmental RF-EMF exposure were downlink and broadcast, and these exposures showed high repeatability. Urbanicity was the most important determinant of total exposure and mobile phone use was the most important determinant of uplink exposure. It is important to continue evaluating RF-EMF exposure in children as device use habits, exposure levels, and main contributing sources may change