Spanish Birth Cohort Research Articles

Gestational weight gain and exposure of newborns to persistent organic pollutants.

Background: Exposure to persistent organic pollutants (POPs) during fetal development can increase the risk of adverse health effects during childhood. Maternal characteristics and physiological changes during gestation, such as gestational weight gain (GWG), may have an influence in the overall burden of POPs in neonates. However, the associations between GWG and POP concentrations are still not well established.Objective: We examined the association of GWG with cord serum POPs concentrations after adjusting for prepregnancy maternal body mass index (BMI) and other potential determinants of the transfer of POPs into newborns. The GWG values were evaluated after grouping by the reference guidelines of the Institute of Medicine (IOM).Methods: We measured levels of 14 organochlorine pesticides, 7 polychlorobiphenyls (PCBs), and 14 polybrominated diphenyl ethers (PBDEs) in 325 cord serum samples from a Spanish birth cohort. Multivariable models were used to estimate associations of GWG, prepregnancy BMI, and other maternal determinants on cord serum concentrations of POPs.Results: Neonatal concentrations of POPs were inversely associated with GWG after adjustment for age, prepregnancy BMI, educational level, and fish consumption. On average, neonates of women with IOM-recommended GWG have lower POP concentrations than do neonates of mothers with inadequate GWG.Conclusions: The present findings suggest an association between neonatal exposure to POPs and inadequate GWG during pregnancy. Encouraging pregnant women to meet the recommended IOM guidelines for GWG may reduce the accumulation of POPs in newborns.Citation: Vizcaino E, Grimalt JO, Glomstad B, Fernández-Somoano A, Tardón A. 2014. Gestational weight gain and exposure of newborns to persistent organic pollutants. Environ Health Perspect 122:873–879; http://dx.doi.org/10.1289/ehp.1306758

Prenatal Bisphenol A Urine Concentrations and Early Rapid Growth and Overweight Risk in the Offspring

Increasing experimental evidence suggests that prenatal bisphenol A (BPA) exposure induces offspring weight gain, but these effects remain largely unexplored in humans. We examined the effects of prenatal BPA exposure on postnatal growth and obesity. BPA concentrations were measured in two spot-urine samples collected in the 1st and 3rd trimesters of pregnancy from mothers in a Spanish birth cohort study (n = 402). We used the average of the two creatinine-adjusted BPA concentrations as the exposure variable. Rapid child growth was defined as a weight gain Z score >0.67 in the first 6 months of life. Age- and sex-specific Z scores for body mass index (BMI) were calculated at age 14 months and 4 years, based on the World Health Organization referent; overweight was defined as a BMI Z score greater than or equal to the 85th percentile. Age- and sex-specific waist circumference Z scores were calculated at age 14 months and 4 years using the analysis population mean. Twenty-six percent of children were rapid growers; 25% were overweight at 14 months and 21% at 4 years. Geometric mean BPA concentrations were 2.6 μg/g creatinine (standard deviation = 2.3) in 1st trimester and 2.0 (2.3) in 3rd trimester samples (Pearson r = 0.13). At 4 years, BPA exposure was associated with increased waist circumference (β per log10 μg/g = 0.28 [95% confidence interval = 0.01 to 0.57]) and BMI (β = 0.28 [-0.06 to 0.63]). BPA was not associated with obesity-related outcomes at earlier ages. This study provides some evidence for an association between prenatal BPA exposure and obesity-related outcomes in childhood, although not in infancy. The large uncertainties in BPA exposure assessment require that findings be interpreted with caution.

Prenatal exposure to persistent organic pollutants and rapid weight gain and overweight in infancy

To examine the effects of prenatal exposure to persistent organic pollutants (POPs) on rapid growth in the first 6 months of life and overweight at 14 months of age. In a Spanish birth cohort study, the POPs dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB), and polychlorinated biphenyls (PCBs-congeners 153, 138, 180) were measured in maternal serum collected in the first trimester of pregnancy during 2003-2008. Rapid growth was defined as a z-score weight gain >0.67 SD between 6 months of age and birth. Overweight at 14 months was defined as a BMI z-score ≥85th percentile. Generalized linear models examined the association between POPs and rapid growth (N = 1285) and overweight (N = 1198). The analysis population included 24% rapid growers and 30% overweight infants. DDE and HCB were positively associated with rapid growth and with overweight. There was some indication that infant sex and exclusive breastfeeding duration may modify the effects of DDE, and that maternal prepregnancy BMI status may influence the effects of HCB. PCBs were not related to postnatal growth. Prenatal exposure to DDE and HCB may be associated with early postnatal growth. Further research is needed to evaluate the persistence of these associations at older ages.

Exposure to BPA during pregnancy and fetal growth in a Spanish birth cohort

Background: Exposure to bisphenol A (BPA) during pregnancy may affect fetal growth and this effect may be sex-specific. Findings are inconsistent and based on only a handful of studies. Only two studies were able to examine BPA effects in specific fetal growth windows during pregnancy. Aims: To examine the association between prenatal BPA exposure and fetal growth during pregnancy windows based on ultrasound measurements in a prospective Spanish birth cohort study. Methods: BPA concentrations were measured in two spot urine samples collected in the 1st and 3rd trimesters of pregnancy (n=463). The average of the two creatinine-adjusted BPA concentrations was used as exposure variable. Ultrasound examinations at each pregnancy trimester were used to fit mixed-effects models and estimate longitudinal growth curves for femur length (FL), head circumference (HC), abdominal circumference (AC), biparietal diameter (BPD), and estimated fetal weight (EFW). These models were applied to calculate conditional standard deviation (SD) scores over pregnancy weeks 12-20 and 20-32. Multivariate linear regression models were adjusted for maternal characteristics (age, parity, education, social class, smoking status) and time of day of urine collection. Results:BPA concentrations (GM±GSD) were 2.5 ± 2.3 ?g/g in 1stand 2.0 ± 2.3 ?g/g in 3rd trimestersamples (correlation=0.15, p=0.001).Exposure to BPA during pregnancy was negatively associated with FL and EFW during weeks 12-20 in boys (FL: ? SD-score for 10-fold increase in µg/g BPA =-0.51, 95%CI=-0.92,-0.10; EFW: ?=-0.59, 95%CI=-1.04, -0.14). None of the other fetal parameters was associated with urinary BPA concentrations, and there were no associations in the 20-32 week period or in girls. Conclusions: Maternal BPA exposure during pregnancy may reduce certain growth parameters in the male fetus. Uncertainties in BPA exposure assessment require that findings be interpreted with caution.

Maternal Smoking During Pregnancy and Fetal Biometry

In utero tobacco exposure has been associated with fetal growth restriction, but uncertainty remains about critical windows of exposure and specific effects on body segments. In the present study, we aimed to examine the association of maternal smoking with fetal biometry in different stages of pregnancy. The study population comprised 2,478 fetuses from a Spanish birth cohort study that was established between 2003 and 2008. Biparietal diameter, femur length, abdominal circumference, and estimated fetal weight were evaluated at 12, 20, and 34 weeks of gestation. Fetal size and growth were assessed by standard deviation scores adjusted by maternal and fetal characteristics. Maternal smoking was assessed using questionnaire and a sample of urinary cotinine at week 32 of gestation. Associations were estimated using multiple regression analysis. Smokers at week 12 of gestation showed decreased fetal growth as reflected by all growth parameters at 20-34 weeks, leading to a reduced fetal size at week 34. The reduction was greatest in femur length, at -9.4% (95% confidence interval -13.4, -5.4) and least in abdominal circumference, at -4.4% (95% CI: -8.7, -0.1). Fetuses of smokers who quit smoking before week 12 showed reduced growth only in femur length (-5.5; 95% CI: -10.1, -0.9). Dose-response curves for smoking versus fetal growth parameters (abscissa: log2 cotinine) were linear for biparietal diameter and femur length.

Dietary and sociodemographic determinants of bisphenol A urine concentrations in pregnant women and children

Bisphenol A (BPA) exposure during early life may have endocrine-disrupting effects, but the dietary and sociodemographic predictors of BPA exposure during pregnancy and childhood remain unclear. Our aim was to evaluate the correlations between, and sociodemographic and dietary predictors of, serial urinary BPA concentrations measured during pregnancy and childhood in a Spanish birth cohort study. BPA was measured in two spot urine samples collected from 479 women during the first and third trimester of pregnancy and in one urine sample from their 4-year old children (n=130). Average dietary intakes were reported in food frequency questionnaires during the first and third pregnancy trimester and at age 4years. Multivariate mixed models and linear regression models were used to estimate associations between sociodemographic and dietary factors and BPA concentrations. A small, but statistically significant correlation was found between serial maternal BPA concentrations measured during pregnancy (r=0.17). Pregnant women who were younger, less-educated, smoked, and who were exposed to second-hand tobacco smoke (SHS) had higher BPA concentrations than others. BPA concentrations were also higher in children exposed to SHS. High consumption of canned fish during pregnancy was associated with 21% [GM ratio=1.21; 95%CI 1.02, 1.44] and 25% [GM ratio=1.25; 95%CI 1.05, 1.49] higher urinary BPA concentrations in the first and third pregnancy trimester, respectively, compared to the lowest consumption group. This study suggests that canned fish may be a major source of BPA during pregnancy in Spain, a country of high canned fish consumption. Further evaluation of specific BPA exposure sources in the sociodemographic group of younger women who smoke, are exposed to SHS, and have a low educational level is needed. Studies identifying sources of exposure would benefit from repeat BPA measurements and questionnaires specifically focused on dietary and packaging sources.

Meconium microbiota types dominated by lactic acid or enteric bacteria are differentially associated with maternal eczema and respiratory problems in infants

Culture-dependent methods have shown that meconium, the newborn's first intestinal discharge, is not sterile, but the diversity of bacteria present in this material needs to be further characterized by means of more sensitive molecular techniques. Our aims were to characterize molecularly the meconium microbiota in term infants, to assess whether it contributes to the future microbiota of the infants' gastrointestinal tract, and to evaluate how it relates to lifestyle variables and atopy-related conditions. We applied high-throughput pyrosequencing of the 16S rRNA gene to study the meconium microbiota in twenty term newborns from a Spanish birth cohort. For comparison, we characterized the microbiota in fecal samples from seven pregnant women days before delivery and in two series of infant samples spanning the first seven months of life. We also compared our data with vaginal and skin microbiota characterized in independent studies. Different types of meconium microbiota were defined based on taxonomic composition and abundance and their associations with different factors were statistically evaluated. The meconium microbiota differs from those in adult feces, vagina and skin, but resembles that of fecal samples from young infants. Meconium samples clustered into two types with different bacterial diversity, richness and composition. One of the types was less diverse, dominated by enteric bacteria and associated with a history of atopic eczema in the mother (P=0.038), whereas the second type was dominated by lactic acid bacteria and associated with respiratory problems in the infant (P=0.040). Our findings suggest that the meconium microbiota has an intrauterine origin and participates in gut colonization. Although based on a small population sample, our association analyses also suggest that the type of bacteria detected in meconium is influenced by maternal factors and may have consequences for childhood health.

Early-Life Exposure to Outdoor Air Pollution and Respiratory Health, Ear Infections, and Eczema in Infants from the INMA Study

Background: Prenatal and early-life periods may be critical windows for harmful effects of air pollution on infant health.Objectives: We studied the association of air pollution exposure during pregnancy and the first year of life with respiratory illnesses, ear infections, and eczema during the first 12–18 months of age in a Spanish birth cohort of 2,199 infants.Methods: We obtained parentally reported information on doctor-diagnosed lower respiratory tract infections (LRTI) and parental reports of wheezing, eczema, and ear infections. We estimated individual exposures to nitrogen dioxide (NO2) and benzene with temporally adjusted land use regression models. We used log-binomial regression models and a combined random-effects meta-analysis to estimate the effects of air pollution exposure on health outcomes across the four study locations.Results: A 10-µg/m3 increase in average NO2 during pregnancy was associated with LRTI [relative risk (RR) = 1.05; 95% CI: 0.98, 1.12] and ear infections (RR = 1.18; 95% CI: 0.98, 1.41). The RRs for an interquartile range (IQR) increase in NO2 were 1.08 (95% CI: 0.97, 1.21) for LRTI and 1.31 (95% CI: 0.97, 1.76) for ear infections. Compared with NO2, the association for an IQR increase in average benzene exposure was similar for LRTI (RR = 1.06; 95% CI: 0.94, 1.19) and slightly lower for ear infections (RR = 1.17; 95% CI: 0.93, 1.46). Associations were slightly stronger among infants whose mothers spent more time at home during pregnancy. Air pollution exposure during the first year was highly correlated with prenatal exposure, so we were unable to discern the relative importance of each exposure period.Conclusions: Our findings support the hypothesis that early-life exposure to ambient air pollution may increase the risk of upper and lower respiratory tract infections in infants.

The use of household cleaning products during pregnancy and lower respiratory tract infections and wheezing during early life

To evaluate the effects of household use of cleaning products during pregnancy on infant wheezing and lower respiratory tract infections (LRTI). In four prospective Spanish birth cohorts (n=2,292), pregnant women reported the use of household cleaning products. When infants were 12-18months old, current cleaning product use and infant's wheezing and LRTI were reported. Cohort-specific associations between the use of specific products and respiratory outcomes were evaluated using multivariable regression analyses and estimates were combined using random-effects meta-analyses. The period prevalence of LRTI was higher when sprays (combined odds ratio (OR)=1.29; 95% confidence interval (CI) 1.04-1.59) or air fresheners (OR=1.29; CI 1.03-1.63) were used during pregnancy. The odds of wheezing increased with spray (OR=1.37; CI 1.10-1.69) and solvent (OR=1.30; CI 1.03-1.62) use. The associations between spray and air freshener use during pregnancy and both outcomes remained apparent when these products were not used after pregnancy. Nevertheless, the estimates were higher when post-natal exposure was included. The use of cleaning sprays, air fresheners and solvents during pregnancy may increase the risk of wheezing and infections in the offspring.

Polybrominated Diphenyl Ethers (PBDEs) in Breast Milk and Neuropsychological Development in Infants

Background: There is increasing interest in the potential effects of polybrominated diphenyl ethers (PBDEs) on children’s neuropsychological development, but only a few small studies have evaluated such effects.Objectives: Our goal was to examine the association between PBDE concentrations in colostrum and infant neuropsychological development and to assess the influence of other persistent organic pollutants (POPs) on such association.Methods: We measured concentrations of PBDEs and other POPs in colostrum samples of 290 women recruited in a Spanish birth cohort. We tested children for mental and psychomotor development with the Bayley Scales of Infant Development at 12–18 months of age. We analyzed the sum of the seven most common PBDE congeners (BDEs 47, 99, 100, 153, 154, 183, 209) and each congener separately.Results: Increasing Σ7PBDEs concentrations showed an association of borderline statistical significance with decreasing mental development scores (β per log ng/g lipid = –2.25; 95% CI: –4.75, 0.26). BDE-209, the congener present in highest concentrations, appeared to be the main congener responsible for this association (β = –2.40, 95% CI: –4.79, –0.01). There was little evidence for an association with psychomotor development. After adjustment for other POPs, the BDE-209 association with mental development score became slightly weaker (β = –2.10, 95% CI: –4.66, 0.46).Conclusions: Our findings suggest an association between increasing PBDE concentrations in colostrum and a worse infant mental development, particularly for BDE-209, but require confirmation in larger studies. The association, if causal, may be due to unmeasured BDE-209 metabolites, including OH-PBDEs (hydroxylated PBDEs), which are more toxic, more stable, and more likely to cross the placenta and to easily reach the brain than BDE-209.

Surrounding Greenness and Pregnancy Outcomes in Four Spanish Birth Cohorts

Background: Green spaces have been associated with improved physical and mental health; however, the available evidence on the impact of green spaces on pregnancy is scarce.Objectives: We investigated the association between surrounding greenness and birth weight, head circumference, and gestational age at delivery.Methods: This study was based on 2,393 singleton live births from four Spanish birth cohorts (Asturias, Gipuzkoa, Sabadell, and Valencia) located in two regions of the Iberian Peninsula with distinct climates and vegetation patterns (2003–2008). We defined surrounding greenness as average of satellite-based Normalized Difference Vegetation Index (NDVI) (Landsat 4–5 TM data at 30 m × 30 m resolution) during 2007 in buffers of 100 m, 250 m, and 500 m around each maternal place of residence. Separate linear mixed models with adjustment for potential confounders and a random cohort effect were used to estimate the change in birth weight, head circumference, and gestational age for 1-interquartile range increase in surrounding greenness.Results: Higher surrounding greenness was associated with increases in birth weight and head circumference [adjusted regression coefficients (95% confidence interval) of 44.2 g (20.2 g, 68.2 g) and 1.7 mm (0.5 mm, 2.9 mm) for an interquartile range increase in average NDVI within a 500-m buffer] but not gestational age. These findings were robust against the choice of the buffer size and the season of data acquisition for surrounding greenness, and when the analysis was limited to term births. Stratified analyses indicated stronger associations among children of mothers with lower education, suggesting greater benefits from surrounding greenness.Conclusions: Our findings suggest a beneficial impact of surrounding greenness on measures of fetal growth but not pregnancy length.

Surrounding Greenness and Pregnancy Outcomes in Four Spanish Birth Cohorts

Surrounding Greenness and Pregnancy Outcomes in Four Spanish Birth Cohorts

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.Objectives: We explored whether prenatal organochlorine compound (OC) concentrations [polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyltrichloroethane (DDT)] were associated with overweight at 6.5 years of age and whether child sex or fat intakes modified these associations.Methods: We studied 344 children from a Spanish birth cohort established in 1997–1998. Overweight at 6.5 years was defined as a body mass index (BMI) z-score ≥ 85th percentile of the World Health Organization reference. Cord blood OC concentrations were measured and treated as categorical variables (tertiles). Children’s diet was assessed by food frequency questionnaire. Relative risks (RRs) were estimated using generalized linear models.Results: After multivariable adjustment, we found an increased RR of overweight in the third tertile of PCB exposure [RR = 1.70; 95% confidence interval (CI): 1.09, 2.64] and the second tertile of DDE exposure (RR = 1.67; 95% CI: 1.10, 2.55), but no association with DDT exposure in the population overall. Associations between overweight and PCB and DDE concentrations were strongest in girls (p-interaction between 0.01 and 0.28); DDT was associated with overweight only in boys. For DDT we observed stronger associations in children with fat intakes at or above compared with below the median, but this interaction was not significant (p-interaction > 0.05).Conclusions: This study suggests that prenatal OC exposures may be associated with overweight in children and that sex and high-fat intake may influence susceptibility.

URINARY CONCENTRATIONS OF PHTHALATES AND PHENOLS IN A POPULATION OF SPANISH PREGNANT WOMEN AND CHILDREN

Background and aims: phthalates and phenols exposure is prevalent among the general population and of potential concern for pregnant women and children because of their suspected susceptibility to endocrine effects. In the present study, we aimed to evaluate the extent of exposure to several phthalates and phenols in a sample of Spanish pregnant women—according to their individual characteristics (age, social class, education, body mass index)—and children who participated in the INMA – Infancia y Medio Ambiente (Environment and Childhood) project. Methods: one spot urine sample was taken during the third trimester of pregnancy from 120 pregnant women and from 30 4-year old children belonging to 5 Spanish birth cohorts, and analysed for 11 phthalate metabolites and 9 phenols. Results: Three metabolites of di(2-ethylhexyl) phthalate, mono-2-ethyl-5-carboxypentyl phthalate, mono-2-ethyl-5-hydroxyhexyl phthalate, and mono-2-ethyl-5-oxohexyl phthalate; two metabolites of dibutyl phthalates, mono-isobutyl phthalate and mono-nbutyl phthalate; monoethyl phthalate (MEP), the main metabolite of diethyl phthalate; and two phenols, methyl paraben (M-PB) and 2,5-dichlorophenol were detected in the urine samples of all women. The highest urinary concentrations were for MEP and M-PB. Urinary concentrations of all phthalate metabolites and of 2,4-dichlorophenol, 2,5-DCP, and bisphenol A were lower in the pregnant women than in the children. Among women, a positive relationship with social class and education was shown for most of the phthalate metabolites and phenols. Almost all phthalate metabolites varied by region even after adjusting for social class and education. Conclusions: Phthalate and phenol exposures are prevalent in a group of pregnant women and young children, two susceptible populations, and these exposures might be positively related to social class.

PERSISTENT ORGANIC POLLUTANTS AND OVERWEIGHT AT AGE 6.5 YEARS; DO SEX OR HIGH-FAT INTAKES OF THE CHILD MATTER?

Background and Aims: Recent experimental evidence suggests prenatal exposure to endocrine-disrupting chemicals may increase postnatal obesity risk, and that these effects may vary by sex or be enhanced when animals are postnatally placed on a high-fat diet. Little is known about these associations in humans. We explored whether prenatal exposure to organochlorine compounds (OC) (PCBs, DDE, DDT) is associated with overweight at age 6.5 years and whether children’s sex or fat intakes modify these associations. Methods: We studied 344 children from a Spanish birth cohort established in 1997/98. OC concentrations were measured in cord blood. Overweight at 6.5 years was defined as a BMI z-score • the 85th percentile of the WHO reference. Using a food frequency questionnaire of children’s diet in the past year, a high-fat intake was defined as above median fat intakes as a percentage of energy. Weestimated relative risks using generalized linear models. Results: Third tertile PCBs exposure was found to be associated with overweight in girls (RRª=2.13, 95%CI=0.99, 2.57), but not clearly in boys (RRª=1.43, 95%CI=0.82, 2.38; p-interaction=0.04). Children with higher-fat intakes had an increased risk of overweight related to third tertile PCBs exposure (RRª=1.95, 95%CI=1.00, 3.82), but the interaction was not statistically significant (p-interaction=0.63). Second tertile DDE exposure was associated with overweight (RRª=1.67, 95%CI=1.10, 2.55), with a somewhat stronger association in girls than boys (p-interaction=0.20). No effect modification by fat intake was observed for DDE (p-interaction=0.93).Second tertile DDT exposure was associated with overweight only in boys (RRª=1.96, 95%CI=1.06, 3.62; p-interaction=0.25) and among children with higher-fat intakes (RR=2.31, 95%CI=1.16, 4.58; p-interaction=0.20). For none of the OC, linear dose-response relationships were observed. Conclusions: Though no clear evidence was found for a dose-response relationship, prenatal PCBs, DDE and DDT concentrations might increase the risk of overweight at 6.5 years in a sex-specific and diet-dependent way.

Urinary concentrations of phthalates and phenols in a population of Spanish pregnant women and children

BackgroundPhthalate and phenol exposure is prevalent among the general population and of potential concern for pregnant women and children because of their suspected susceptibility to endocrine effects. ObjectivesTo evaluate the extent of exposure to several phthalates and phenols in a sample of Spanish pregnant women – according to their individual characteristics (age, social class, education, and body mass index) – and children who participated in the INMA — Infancia y Medio Ambiente (Environment and Childhood) project. MethodsOne spot urine sample was taken during the third trimester of pregnancy from 120 pregnant women and from 30 4-year old children belonging to 5 Spanish birth cohorts, and analyzed for 11 phthalate metabolites and 9 phenols. ResultsThree metabolites of di(2-ethylhexyl) phthalate, mono-2-ethyl-5-carboxypentyl phthalate, mono-2-ethyl-5-hydroxyhexyl phthalate, and mono-2-ethyl-5-oxohexyl phthalate; two metabolites of dibutyl phthalates, mono-isobutyl phthalate and mono-n-butyl phthalate; monoethyl phthalate (MEP), the main metabolite of diethyl phthalate; and two phenols, methyl paraben (M-PB) and 2,5-dichlorophenol were detected in the urine samples of all women. The highest urinary concentrations were for MEP and M-PB. Urinary concentrations of all phthalate metabolites and of 2,4-dichlorophenol, 2,5-dichlorophenol, and bisphenol A were lower in the pregnant women than in the children. Among women, a positive relationship with social class and education was shown for most of the phthalate metabolites and phenols. Almost all phthalate metabolites varied by region even after adjusting for social class and education. ConclusionsPhthalate and phenol exposures are prevalent in a group of pregnant women and young children, two susceptible populations, and these exposures might be positively related to social class.

Prenatal Exposure to Mercury, Fish Consumption During Pregnancy and Associated Factors in Four Spanish Birth Cohorts (INMA Project)

ISEE-0561 Background and Objective: High prenatal exposure to mercury (Hg) has been related with neurodevelopmental deficits in children. Fish consumption is the main source of Hg exposure. Our objective is to assess total Hg (T-Hg) exposure in newborn and associated factors in 4 cohorts of the Spanish Environment and Childhood (INMA) Project. Methods: Study population included 1,888 mother and child pairs from 4 areas of Spain, i.e. Asturias (340), Gipuzkoa (533), Sabadell (461), and Valencia (554). T-Hg concentration in cord blood was determined by atomic absorption spectrometry. Information on socio-demographic characteristics, occupational history, and life-style was obtained through 3 questionnaires completed in the 1st and 3rd trimester of pregnancy. Fish intake was assessed by a food frequency questionnaire at 3rd trimester that included eleven items for fish intake. ANCOVA was used for multivariate analysis. Results: T-Hg levels were below LOD in 89 samples (4.7%). Geometric mean (interquartile range) for each cohort was 10.8 μg/L (6.6–18.8), 7.5 (5.1–12.0), 6.3 (4.1–10.0), and 9.5 (5.3–18.0), respectively. Sixty-eight percent of samples showed T-Hg levels above the EPA reference dose equivalent (5.8 μg/L). The mean daily fish intake was 73 g/day; white fish, canned tuna, and big oily fish provided the main contribution to fish intake. Statistically significant increases of 12.5, 7.6, 6.7 and 3.4% in T-Hg levels were observed for 100 g/week increase in the intake of big oily fish, white fish, canned tuna and the remaining fish, respectively. Conclusion: We found elevated T-Hg levels in cord blood in Spain similar to other high consumption populations. It is necessary to develop actions to prevent high prenatal exposure to mercury including guidance to pregnant women in making prudent dietary choices as well as public health control of Hg concentration in marketed fish. Funding: ISCIII (INMAG03/176, FIS: 03/1615, 04/1112, 04/1509, 06/1213) and Conselleria Sanitat-GV, Spain.

Concentrations and determinants of outdoor, indoor and personal nitrogen dioxide in pregnant women from two Spanish birth cohorts

Determinants of outdoor, indoor and personal concentrations of nitrogen dioxide (NO 2) were assessed in a subset of pregnant women of the Spanish INMA (Environment and Childhood) Study. Home indoor and outdoor NO 2 concentrations were measured during 48 h with passive samplers for 50 and 58 women from the INMA cohorts of Valencia and Sabadell, respectively. Women from Sabadell also carried personal NO 2 samplers during the same period. Data on time–activity patterns, socio-economic characteristics, and environmental exposures were obtained through questionnaires. Multiple linear regression models were developed to predict NO 2 levels. In Valencia, median outdoor NO 2 levels (42 µg/m 3) were higher than median indoor levels (36 µg/m 3). In Sabadell, personal NO 2 showed the highest median levels (40 µg/m 3), followed by indoor (32 µg/m 3) and outdoor (29 µg/m 3) levels. Personal exposure to NO 2 correlated best with the indoor NO 2 levels. Temporal and traffic-related variables were significant predictors for outdoor NO 2 levels. Thirty-two percent of the indoor NO 2 variability in the two cohorts was explained by outdoor NO 2 levels and the use of the gas appliances. The model for personal exposure accounted for 59% of the variance in NO 2 levels in Sabadell with four predictor variables (outdoor and indoor NO 2 levels, time spent in outdoor environments and time exposed to a gas cooker). No significant association was found between personal or indoor NO 2 levels and exposure to environmental tobacco smoke (ETS) at home. Personal NO 2 levels were found to be strongly influenced by indoor NO 2 concentrations. The study supports the use of time–activity patterns along with indoor measurements to predict personal exposure to traffic-related air pollution.

The Impact of Women's Educational and Economic Resources on Fertility. Spanish Birth Cohorts 1901-1950

In this chapter we portray the effects of female education and professional achievement on fertility decline in Spain over the period 1920-1980 (birth cohorts of 1900-1950). A longitudinal econometric approach is used to test the hypothesis that the effects of women's education in the revaluing of their time had a very significant influence on fertility decline. Although in the historical context presented here improvements in schooling were on a modest scale, they were continuous (with the interruption of the Civil War) and had a significant impact in shaping a model of low fertility in Spain. We also stress the relevance of this result in a context such as the Spanish for which liberal values were absent, fertility control practices were forbidden, and labour force participation of women was politically and socially constrained.