Pre and postnatal exposure to mercury and respiratory health in preschool children from the Spanish INMA Birth Cohort Study.

Effects of mercury on maturing immune system have been reported, however the association with respiratory and allergy problems during infancy remains unclear. The aim of this study is to evaluate the association between pre and postnatal mercury exposure and respiratory and allergy problems among preschool children and to examine the role of potential modifying factors. Study subjects were children participant in Spanish Childhood and Environment Project (INMA, 2003-2008). We measured total mercury levels in cord blood (n = 1868) and hair at 4 years of age (n = 1347). Respiratory outcomes (wheezing, severe wheezing, chestiness, persistent cough, eczema and otitis) were obtained by questionnaires administered to parents. Associations were investigated by logistic regression adjusted for socio-demographic and lifestyle-related variables in each cohort and subsequent meta-analysis. We tested effect modification by factors related to individual susceptibility, diet and co-exposure with other pollutants. The geometric mean of cord blood and hair total mercury was 8.20 µg/L and 0.97 µg/g, respectively. No statistically significant association between pre or postnatal mercury exposure and respiratory and allergy outcomes was found. Notwithstanding, lower maternal intake of fruits and vegetables increased the risk of some respiratory outcomes due to the prenatal exposure to mercury (pint < 0.05). Moreover, an inverse association between prenatal mercury exposure and some respiratory outcomes was observed among children with higher maternal exposure to organocholorine compounds or smoking (pint < 0.05). Also, sex and postnatal smoking exposure modulated mercury postnatal effects on persistent cough (pint < 0.05). In conclusion, no association between pre and postnatal mercury exposure and respiratory and allergy problems among the whole population at study was found. However, diet and other toxicants could modulate this relation, especially during prenatal period. More research on this topic is warranted due to the limited evidence.

Association between estimated whole-brain radiofrequency electromagnetic fields dose and cognitive function in preadolescents and adolescents.

OBJECTIVE: To investigate the association between estimated whole-brain radiofrequency electromagnetic fields (RF-EMF) dose, using an improved integrated RF-EMF exposure model, and cognitive function in preadolescents and adolescents. METHODS: Cross-sectional analysis in preadolescents aged 9-11 years and adolescents aged 17-18 years from the Dutch Amsterdam Born Children and their Development Study (n = 1664 preadolescents) and the Spanish INfancia y Medio Ambiente Project (n = 1288 preadolescents and n = 261 adolescents), two population-based birth cohort studies. Overall whole-brain RF-EMF doses (mJ/kg/day) were estimated for several RF-EMF sources together including mobile and Digital Enhanced Cordless Telecommunications phone calls (named phone calls), other mobile phone uses than calling, tablet use, laptop use (named screen activities), and far-field sources. We also estimated whole-brain RF-EMF doses in these three groups separately (i.e. phone calls, screen activities, and far-field) that lead to different patterns of RF-EMF exposure. We assessed non-verbal intelligence in the Dutch and Spanish preadolescents, information processing speed, attentional function, and cognitive flexibility in the Spanish preadolescents, and working memory and semantic fluency in the Spanish preadolescents and adolescents using validated neurocognitive tests. RESULTS: Estimated overall whole-brain RF-EMF dose was 90.1 mJ/kg/day (interquartile range (IQR) 42.7; 164.0) in the Dutch and Spanish preadolescents and 105.1 mJ/kg/day (IQR 51.0; 295.7) in the Spanish adolescents. Higher overall estimated whole-brain RF-EMF doses from all RF-EMF sources together and from phone calls were associated with lower non-verbal intelligence score in the Dutch and Spanish preadolescents (-0.10 points, 95% CI -0.19; -0.02 per 100 mJ/kg/day increase in each exposure). However, none of the whole-brain RF-EMF doses was related to any other cognitive function outcome in the Spanish preadolescents or adolescents. CONCLUSIONS: Our results suggest that higher brain exposure to RF-EMF is related to lower non-verbal intelligence but not to other cognitive function outcomes. Given the cross-sectional nature of the study, the small effect sizes, and the unknown biological mechanisms, we cannot discard that our resultsare due to chance finding or reverse causality. Longitudinal studies on RF-EMF brain exposure and cognitive function are needed.

Associations of black carbon with lung function and airway inflammation in schoolchildren.

BACKGROUND: Few studies have investigated the 24-hour respiratory health effects of personal black carbon (BC) and ultrafine particles (UFP) exposure in schoolchildren. The objective of this study was to investigate these associations with the lung function in children 10-years old with and without persistent respiratory symptoms. METHODS: We conducted a cross-sectional study in 305 children (147 and 158 with and without persistent respiratory symptoms, respectively) from three European birth-cohorts: PARIS (France) and INMA Sabadell and Valencia (Spain). Personal 24-hour measurements of exposure concentrations to BC and UFP were performed by portable devices, before lung function testing. Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and the fraction of exhaled nitric oxide (FeNO) were determined. RESULTS: There was no association of UFP with lung function parameters or FeNO whereas the increase in 24-hour BC exposure concentrations was related to a statistically significant decrease in lung function parameters only among children with persistent respiratory symptoms [-96.8 mL (95% Confidence Interval CI: -184.4 to -9.1 mL) in FVC, and -107.2 mL (95% CI: -177.5 to -36.9 mL) in FEV1 for an inter-quartile range of 1160 ng/m3 exposure increase]. A significant positive association between BC and FeNO was observed only in children with persistent respiratory symptoms with current wheezing and/or medication to improve breathing [FeNO increases with +6.9 ppb (95% CI: 0.7 to 13.1 ppb) with an inter-quartile range BC exposure increase]. CONCLUSION: Children suffering from persistent respiratory symptoms appear to be more vulnerable to BC exposure.

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

BACKGROUND: 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. METHODS: Personal environmental RF-EMF exposure (µW/m2, 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). RESULTS: Median total personal RF-EMF exposure was 75.5 µW/m2. Downlink was the largest contributor to total exposure (median: 27.2 µW/m2) followed by broadcast (9.9 µW/m2). Exposure from uplink (4.7 µW/m2) was lower. WiFi and DECT contributed very little to exposure levels. Exposure was higher during day (94.2 µW/m2) than night (23.0 µW/m2), and slightly higher during weekends than weekdays, although varying across regions. Median exposures were highest while children were outside (157.0 µW/m2) or traveling (171.3 µW/m2), and much lower at home (33.0 µW/m2) or in school (35.1 µW/m2). 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. CONCLUSION: 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.

[Exposure to nitrogen dioxide and respiratory health at 2 years in the INMA-Valencia cohort]. / Exposición ambiental a dióxido de nitrógeno y salud respiratoria a los 2 años en la Cohorte INMA-Valencia.

OBJECTIVE: To analyze the association between exposure to nitrogen dioxide (NO2) during pregnancy and the postnatal period up to the age of 2 years old and the incidence of respiratory problems in children from the INMA-Valencia cohort. METHODS: The study population included 624 children from the INMA-Valencia cohort. Individual exposure to NO2 was estimated in different environments outside the home during pregnancy and up to the age of 2 using empirical measurement and data from geo-statistical methods. Respiratory symptoms were obtained from a questionnaire applied at the age of two. The association between NO2 exposure and respiratory symptoms was performed using multivariate logistic regression. RESULTS: The cumulative incidence was 16.3% for persistent cough, 34.9% for wheezing and 27.6% for lower respiratory tract infections. No association was found between respiratory symptoms and exposure to NO2 in any of the children. However an association between NO2 exposure and persistent cough was found at two years of life in the children with a parental history of allergy. CONCLUSION: NO2 exposure would lead to persistent cough in children with a parental history of allergies.

Variations in the prevalence of childhood asthma and wheeze in MeDALL cohorts in Europe.

While there is evidence for variations in prevalence rates of childhood wheeze and asthma between countries, longitudinal, individual-level data are needed to understand these differences. The aim of this study was to examine variations in prevalence rates of childhood asthma, wheeze and wheeze with asthma in Europe. We analysed datasets from 10 MeDALL (Mechanisms of the Development of ALLergy) cohorts in eight countries, representing 26 663 children, to calculate prevalence rates of wheeze and asthma by child age and wheeze with asthma at age 4 years. Harmonised variables included outcomes parent-reported wheeze and parent-reported doctor-diagnosed asthma, and covariates maternal education, parental smoking, pets, parental asthma, doctor-diagnosed allergic rhinitis, doctor-diagnosed eczema and wheeze severity. At age 4 years, asthma prevalence varied from 1.72% in Germany to 13.48% in England and the prevalence of wheeze varied from 9.82% in Greece to 55.37% in Spain. Adjusted estimates of the proportion of 4-year-old children with wheeze diagnosed with asthma remained highest in England (38.14%, 95% CI 31.38-44.90%) and lowest in Spain (15.94%, 95% CI 6.16-25.71%). The large differences in prevalence rates of asthma, wheeze and wheeze with asthma at age 4 years between European cohorts may indicate that childhood asthma is more readily diagnosed in some countries while going unrecognised elsewhere.

Infants' indoor and outdoor residential exposure to benzene and respiratory health in a Spanish cohort.

Benzene exposure represents a potential risk for children's health. Apart from being a known carcinogen for humans (group 1 according to IARC), there is scientific evidence suggesting a relationship between benzene exposure and respiratory problems in children. But results are still inconclusive and inconsistent. This study aims to assess the determinants of exposure to indoor and outdoor residential benzene levels and its relationship with respiratory health in infants. Participants were 1-year-old infants (N = 352) from the INMA cohort from Valencia (Spain). Residential benzene exposure levels were measured inside and outside dwellings by means of passive samplers in a 15-day campaign. Persistent cough, low respiratory tract infections and wheezing during the first year of life, and covariates (dwelling traits, lifestyle factors and sociodemographic data) were obtained from parental questionnaires. Multiple Tobit regression and logistic regression models were performed to assess factors associated to residential exposure levels and health associations, respectively. Indoor levels were higher than outdoor ones (1.46 and 0.77 µg/m3, respectively; p < 0.01). A considerable percentage of dwellings, 42% and 21% indoors and outdoors respectively, surpassed the WHO guideline of 1.7 µg/m3 derived from a lifetime risk of leukemia above 1/100 000. Monitoring season, maternal country of birth and parental tobacco consumption were associated with residential benzene exposure (indoor and outdoors). Additionally, indoor levels were associated with mother's age and type of heating, and outdoor levels were linked with zone of residence and distance from industrial areas. After adjustment for confounding factors, no significant associations were found between residential benzene exposure levels and respiratory health in infants. Hence, our study did not support the hypothesis for the benzene exposure effect on respiratory health in children. Even so, it highlights a public health concern related to the personal exposure levels, since a considerable number of children surpassed the abovementioned WHO guideline for benzene exposure.