Early childhood growth is associated with lung function at 7†years: a prospective population-based study.

Previous studies have related early postnatal growth with later lung function but their interpretation is limited by the methods used to assess a child's growth. We aimed to assess the association of early childhood growth, measured by body mass index (BMI) trajectories up to 4 years, with lung function at 7 years.We included 1257 children from the Spanish Infancia y Medio Ambiente population-based birth cohort. Early childhood growth was classified into five categories based on BMI trajectories up to 4 years previously identified using latent class growth analysis. These trajectories differed in birth size ("lower", "average", "higher") and in BMI gain velocity ("slower", "accelerated"). We related these trajectories to lung function (forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC and forced expiratory flow at 25%-75% of FVC (FEF25-75%)) at 7 years, using multivariable mixed regression.Compared to children with average birth size and slower BMI gain (reference), children with higher birth size and accelerated BMI gain had a higher FVC % pred (3.3%, 95% CI 1.0%-5.6%) and a lower FEV1/FVC % pred (-1.5%, 95% CI -2.9%--0.1%) at 7 years. Similar associations were observed for children with lower birth size and accelerated BMI gain. Children with lower birth size and slower BMI gain had lower FVC % pred at 7 years. No association was found for FEF25-75%Independently of birth size, children with accelerated BMI gain in early childhood had higher lung function at 7 years but showed airflow limitation. Children with lower birth size and slower BMI gain in early childhood had lower lung function at 7 years.

Prenatal Se concentrations and anthropometry at birth in the INMA study (Spain).

We assessed whether prenatal selenium (Se) exposure is associated with anthropometry at birth, placental weight and gestational age. Study subjects were 1249 mother-child pairs from the Valencia and Gipuzkoa cohorts of the Spanish Childhood and Environment Project (INMA, 2003-2008). Se was determined in serum samples taken at the first trimester of pregnancy. Socio-demographic and dietary characteristics were also collected by questionnaires. Mean (SD) serum Se concentration was 79.57 (9.64) µg/L. Se showed weak associations with both head circumference and gestational age. The association between serum Se concentration and birth weight and length was negative, and direct for placental weight and probability of preterm birth, although the coefficients did not reach statistical significance. Individuals with total mercury (THg) levels >15 µg/L reversed the serum Se concentration effect on head circumference. Significant interactions were found between sex and both gestational age and prematurity. Spontaneous birth gestational ages were estimated to be lower for males and their probability of prematurity was higher. In conclusion, prenatal Se exposure may be associated with lower head circumference and lower gestational ages at spontaneous birth. Interactions with THg exposure and gender should be considered when assessing these relationships.

Comparison of urinary iodine levels in women of childbearing age during and after pregnancy.

PURPOSE: Median urinary iodine concentration (UIC) is used to describe the iodine status of a population. However, the link between UIC and iodine intake may vary during pregnancy. The aim of this study was to compare UIC during and after pregnancy, adjusting for factors that affect iodine intake. METHODS: Two repeated measures of UIC and data on maternal iodine intake estimated through questionnaires were collected during pregnancy and 1-4 years after pregnancy in a subsample of women (n = 598) from a mother and child cohort study in Spain. Random-effects interval regression was used to assess the changes in UIC according to pregnancy status. RESULTS: Median UIC was similar during (133 µg/L) and after pregnancy (139 µg/L). After adjusting for iodised salt, iodine supplement consumption, and socio-demographic related variables, UIC was 24.0% (95% CI 11.3, 38.2) higher after than during pregnancy. This difference was maintained in a subsample of women with exhaustive information on diet (n = 291): 26.2%, 95% CI 10.3, 44.4. CONCLUSIONS: In an iodine sufficient area for the general population, iodine excretion was lower during than after pregnancy when factors affecting iodine intake were controlled for. Current recommendations of median UIC during pregnancy are based on the equivalence between iodine intake and UIC estimated from studies in non-pregnant populations, which might lead to overestimation of iodine deficiency during gestation. Further studies should evaluate the equivalence between iodine intake and its urinary excretion during pregnancy.

Urban regeneration as population health intervention: a health impact assessment in the Bay of Pasaia (Spain).

BACKGROUND: An important health issue in urban areas is how changes arising from the regeneration of city-areas affect social determinants of health and equity. This paper examines the impacts attributable to a new fish market and to delays in the regeneration of a port area in a deteriorated region of the Bay of Pasaia (Spain). Potential differential impacts on local residents and socially vulnerable groups were evaluated to determine health inequalities. METHODS: An in-depth, prospective and concurrent Health-Impact-Assessment (HIA) focused on equity was conducted by the regional Public Health Department, following the Merseyside guidelines. Data from different sources was triangulated and impacts were identified using qualitative and quantitative methods. RESULTS: The intervention area is characterised by poor social, environmental, and health indicators. The distinctness of the two projects generates contrasting health and inequality impacts: generally positive for the new fish market and negative for the port area. The former creates recreational spaces and improves urban quality and social cohesion. By contrast, inaction and stagnation of the project in the port area perpetuates deterioration, a lack of safety, and poor health, as well as increased social frustration. CONCLUSIONS: In addition to assessing the health impacts of both projects this HIA promoted intersectoral partnerships, boosted a holistic and positive view of health and incorporated health and equity into the political discourse. Community-level participatory action enabled public health institutions to respond to new urban planning challenges and responsibilities in a more democratic manner.

Exposure to ambient air pollution during pregnancy and preterm birth: A Spanish multicenter birth cohort study.

BACKGROUND AND OBJECTIVE: Preterm birth is a major determinant of infant mortality and morbidity. Air pollution has been suggested as a risk factor for preterm delivery; however, the scientific evidence on this impact remains inconsistent. We assessed the association between residential exposure to air pollution during pregnancy and preterm birth (gestational age at delivery <37 weeks) in Spain. METHODS: This study was based on 2409 pregnant women participating in the INMA birth cohorts in Asturias, Gipuzkoa, Sabadell and Valencia. Ambient levels of nitrogen dioxide (NO2) and benzene were estimated for each woman's residence for each trimester and for the whole pregnancy, using temporally adjusted land-use regression models. The association between air pollution exposure and preterm birth was assessed for each cohort separately by means of logistic regression models controlling for potential confounders, under single- and two-pollutant models, for all the women in the study and for those spending more than 15h/day at home. Combined estimates of the association across cohorts were obtained through meta-analysis. RESULTS: Throughout the whole sample, suggestive but no statistically significant associations were found between exposure and preterm birth. For pregnant women spending more time at home significant associations were found for both pollutants, under single- and two-pollutant models. Under the last ones, NO2 exposure during the second trimester and the whole pregnancy was associated with a higher risk of preterm delivery (OR=1.58, (95%CI: 1.04-2.42) per 10µg/m(3) increase). Benzene exposure during the third trimester was also associated with preterm birth in that subsample (OR=1.45, (95%CI: 1.00-2.09) per 1µg/m(3) increase). CONCLUSION: We found suggestive associations between NO2 and benzene exposure during pregnancy and preterm birth. Estimates of the association were higher among women who spent more time at home, probably reflecting a better exposure assessment in this group.

Prenatal mercury exposure and birth outcomes.

BACKGROUND: Results regarding the association between mercury exposure and anthropometry at birth, gestational length and placental weight are inconsistent, as is the role of seafood intake in these associations. OBJECTIVE: We assessed whether prenatal mercury exposure is associated with anthropometry at birth, placental weight and gestational length in a population with a relatively high exposure to mercury from seafood consumption. METHODS: Total mercury (T-Hg) was determined in cord blood from 1869 newborns with birth outcome measures, within the Spanish multicenter INMA cohort from 2004 to 2008. We adjusted cohort specific linear and Cox regression models to evaluate the association between T-Hg and birth anthropometry (weight, length, and head circumference), placental weight and gestational length. Non-spontaneous labor was taken to be censoring in the survival analysis. Final estimates were obtained using meta-analysis. RESULTS: Geometric mean T-Hg was 8.2µg/L. A doubling of T-Hg was associated with a 7.7g decrease in placental weight (95% CI: -13.6, -1.8) and marginally with head circumference (beta: -0.052cm, 95% CI: -0.109, 0.005). T-Hg was also inversely related to weight and length, although with weaker estimates. Mercury exposure was not associated with the length of gestation. The inverse relation between T-Hg and growth was enhanced when the intake of different seafood groups was adjusted for in the models. CONCLUSIONS: Prenatal mercury exposure may be associated with reduced placental and fetal growth. Confounding by fish intake should be considered when assessing these relationships.

Intrauterine and early postnatal exposure to outdoor air pollution and lung function at preschool age.

BACKGROUND: Effects of prenatal and postnatal exposure to air pollution on lung function at preschool age remain unexplored. We examined the association of exposure to air pollution during specific trimesters of pregnancy and postnatal life with lung function in preschoolers. METHODS: Lung function was assessed with spirometry in preschoolers aged 4.5 years (n=620) participating in the INfancia y Medio Ambiente (INMA) cohort. Temporally adjusted land use regression (LUR) models were applied to estimate individual residential exposures to benzene and nitrogen dioxide (NO2) during specific trimesters of pregnancy and early postnatal life (the first year of life). Recent and current (1 year and 1 week before lung function testing, respectively) exposures to NO2 and nitrogen oxides (NOx) were also assessed. RESULTS: Exposure to higher levels of benzene and NO2 during pregnancy was associated with reduced lung function. FEV1 estimates for an IQR increase in exposures during the second trimester of pregnancy were -18.4 mL, 95% CI -34.8 to -2.1 for benzene and -28.0 mL, 95% CI -52.9 to -3.2 for NO2. Relative risk (RR) of low lung function (<80% of predicted FEV1) for an IQR increase in benzene and NO2 during the second trimester of pregnancy were 1.22, 95% CI 1.02 to 1.46 and 1.30, 95% CI 0.97 to 1.76, respectively. Associations for early postnatal, recent and current exposures were not statistically significant. Stronger associations appeared among allergic children and those of lower social class. CONCLUSIONS: Prenatal exposure to residential traffic-related air pollution may result in long-term lung function deficits at preschool age.

Maternal thyroid dysfunction during gestation, preterm delivery, and birthweight. The Infancia y Medio Ambiente Cohort, Spain.

BACKGROUND: Maternal clinical thyroid disorders can cause reproductive complications. However, the effects of mild thyroid dysfunctions are not yet well established. The aim was to evaluate the association of maternal thyroid function during the first half of pregnancy with birthweight and preterm delivery. METHODS: We analysed data on 2170 pregnant women and their children from a prospective population-based cohort study in four Spanish areas. Mid-gestation maternal serum and urine samples were gathered to determine thyroid-stimulating hormone (TSH), free thyroxine (fT4 ), and urinary iodine concentration (UIC). Thyroid status was defined according to percentile distribution as: euthyroid (TSH and fT4 >5th and <95th percentiles); hypothyroxinaemia (fT4 < 5 th percentile and TSH normal), hypothyroidism (TSH > 95th percentile and fT4 normal or <5th percentile), hyperthyroxinaemia (fT4 > 95 th percentile and TSH normal), and hyperthyroidism (TSH < 5 th percentile and fT4 normal or >95th percentile). Response variables were birthweight, small and large for gestational age (SGA/LGA), and preterm delivery. RESULTS: An inverse association of fT4 and TSH with birthweight was found, the former remaining when restricted to euthyroid women. High fT4 levels were also associated with an increased risk of SGA [odds ratio, 95% confidence interval (CI) 1.28 (95% CI 1.08, 1.51)]. Mean birthweight was higher in the hypothyroxinaemic group (ß = 109, P < 0.01). Iodine intake and UIC were not associated with birth outcomes. CONCLUSIONS: High maternal fT4 levels during the first half of pregnancy were related to lower birthweight and increased risk of SGA newborns, suggesting that maternal thyroid function may affect fetal growth, even within the normal range.

Transfer of perfluoroalkyl substances from mother to fetus in a Spanish birth cohort.

INTRODUCTION: Prenatal exposure to perfluoroalkyl substances (PFAS) might affect child health; thus estimating PFAS fetal burden is relevant. PFAS fetal burden is best estimated in cord samples; previous studies have used either maternal plasma or serum during pregnancy as proxy, but their validity is not clear. We aimed to evaluate PFAS transfer between mother and fetus and determine its predictors in a Spanish birth cohort. METHODS: We measured perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorononanoate (PFNA) in maternal blood and cord serum from 66 mother-child pairs. We used Spearman's rank coefficients to correlate PFAS concentrations in first trimester maternal plasma and serum, with cord serum samples. We assessed PFAS placental transfer by calculating maternal to cord ratios and examined their association with maternal socio-demographic characteristics and child sex using linear regression models. RESULTS: Median concentrations of PFAS (ng/mL) of PFHxS, PFOS, PFOA, and PFNA in maternal plasma (0.79, 6.18, 2.85 and 0.84, respectively) and serum (0.84, 6.99, 2.97 and 0.85) were higher than in cord serum (0.40, 1.86, 1.90 and 0.32). PFBS was not detected. Positive Spearman's correlations (p-values<0.001) were found between maternal plasma and serum (⍴≥0.80), maternal plasma and cord (⍴≥0.66), and maternal serum and cord samples (⍴≥0.67). Maternal plasma to cord ratios were above 1 (PFHxS: 2.35 [95%CI: 2.05, 2.70], PFOS: 3.33 [3.05, 3.62], PFOA: 1.37 [1.27, 1.48], PFNA: 2.39 [2.18, 2.63]); maternal serum to cord ratios were similar. Maternal to cord ratios decreased with maternal age, but not with other socio-demographic factors. CONCLUSIONS: Our results suggest that PFAS fetal body burden can be assessed using as proxy maternal plasma or serum collected early in pregnancy. Maternal age might influence PFAS placental transfer.

[Shigella sonnei outbreak in a school in Northern Spain]. / Brote de Shigella sonnei en un centro escolar de Gipuzkoa.

In October 2012, an outbreak of acute gastroenteritis caused by Shigella sonnei was detected in a nursery and primary school in the north of Spain affecting 112 people: 63.7% were pupils and teachers and 35.7% their co-habitants. The source was a sick child who had travelled to an endemic country, and the key trigger factor was inadequate hygiene in one of the toilets of the school. The enforcement of strict hygiene measures was essential for controlling the outbreak.

Preterm birth, infant weight gain, and childhood asthma risk: a meta-analysis of 147,000 European children.

BACKGROUND: Preterm birth, low birth weight, and infant catch-up growth seem associated with an increased risk of respiratory diseases in later life, but individual studies showed conflicting results. OBJECTIVES: We performed an individual participant data meta-analysis for 147,252 children of 31 birth cohort studies to determine the associations of birth and infant growth characteristics with the risks of preschool wheezing (1-4 years) and school-age asthma (5-10 years). METHODS: First, we performed an adjusted 1-stage random-effect meta-analysis to assess the combined associations of gestational age, birth weight, and infant weight gain with childhood asthma. Second, we performed an adjusted 2-stage random-effect meta-analysis to assess the associations of preterm birth (gestational age <37 weeks) and low birth weight (<2500 g) with childhood asthma outcomes. RESULTS: Younger gestational age at birth and higher infant weight gain were independently associated with higher risks of preschool wheezing and school-age asthma (P < .05). The inverse associations of birth weight with childhood asthma were explained by gestational age at birth. Compared with term-born children with normal infant weight gain, we observed the highest risks of school-age asthma in children born preterm with high infant weight gain (odds ratio [OR], 4.47; 95% CI, 2.58-7.76). Preterm birth was positively associated with an increased risk of preschool wheezing (pooled odds ratio [pOR], 1.34; 95% CI, 1.25-1.43) and school-age asthma (pOR, 1.40; 95% CI, 1.18-1.67) independent of birth weight. Weaker effect estimates were observed for the associations of low birth weight adjusted for gestational age at birth with preschool wheezing (pOR, 1.10; 95% CI, 1.00-1.21) and school-age asthma (pOR, 1.13; 95% CI, 1.01-1.27). CONCLUSION: Younger gestational age at birth and higher infant weight gain were associated with childhood asthma outcomes. The associations of lower birth weight with childhood asthma were largely explained by gestational age at birth.

Prenatal exposure to DDE and PCB 153 and respiratory health in early childhood: a meta-analysis.

BACKGROUND: Persistent organic pollutants may affect the immune and respiratory systems, but available evidence is based on small study populations. We studied the association between prenatal exposure to dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyl 153 (PCB 153) and children's respiratory health in European birth cohorts. METHODS: We included 4608 mothers and children enrolled in 10 birth cohort studies from 7 European countries. Outcomes were parent-reported bronchitis and wheeze in the first 4 years of life. For each cohort, we performed Poisson regression analyses, modeling occurrences of the outcomes on the estimates of cord-serum concentrations of PCB 153 and DDE as continuous variables (per doubling exposure) and as cohort-specific tertiles. Summary estimates were obtained through random-effects meta-analyses. RESULTS: The risk of bronchitis or wheeze (combined variable) assessed before 18 months of age increased with increasing DDE exposure (relative risk [RR] per doubling exposure = 1.03 [95% confidence interval = 1.00-1.07]). When these outcomes were analyzed separately, associations appeared stronger for bronchitis. We also found an association between increasing PCB 153 exposure and bronchitis in this period (RR per doubling exposure = 1.06 [1.01-1.12]) but not between PCB 153 and wheeze. No associations were found between either DDE or PCB 153 and ever-wheeze assessed after 18 months. Inclusion of both compounds in the models attenuated risk estimates for PCB 153 tertiles of exposure, whereas DDE associations were more robust. CONCLUSION: This large meta-analysis suggests that prenatal DDE exposure may be associated with respiratory health symptoms in young children (below 18 months), whereas prenatal PCB 153 levels were not associated with such symptoms.

Mediterranean diet adherence during pregnancy and risk of wheeze and eczema in the first year of life: INMA (Spain) and RHEA (Greece) mother-child cohort studies.

Maternal diet during pregnancy might influence the development of childhood allergic disorders. The aim of the present study was to evaluate the impact of Mediterranean diet (MD) adherence during pregnancy on wheeze and eczema in the first year of life in two population-based mother-child cohorts in Spain and Greece. We studied 1771 mother-newborn pairs from the Spanish multi-centre 'INMA' (INfancia y Medio Ambiente) study (Gipuzkoa, Sabadell and Valencia) and 745 pairs from the 'RHEA' study in Crete, Greece. The symptoms of wheeze and eczema were based on the criteria of the International Study of Asthma and Allergies in Childhood. Maternal diet during pregnancy was assessed by FFQ and MD adherence was evaluated through an a priori score. Multivariate log-binomial regression models were used to adjust for several confounders in each cohort and summary estimates were obtained by a meta-analysis. MD adherence was not associated with the risk of wheeze and eczema in any cohort, and similar results were identified in the meta-analysis approach. High meat intake (relative risk (RR) 1·22, 95 % CI 1·00, 1·49) and 'processed' meat intake (RR 1·18, 95 % CI 1·02, 1·37) during pregnancy were associated with an increased risk of wheeze in the first year of life, while a high intake of dairy products was significantly associated with a decreased risk of infantile wheeze (RR 0·83, 95 % CI 0·72, 0·96). The results of the present study show that high meat intake during pregnancy may increase the risk of wheeze in the first year of life, while a high intake of dairy products may decrease it.

Maternal prepregnancy obesity is an independent risk factor for frequent wheezing in infants by age 14 months.

BACKGROUND: Maternal prepregnancy obesity has been linked to the offspring's risk for subsequent asthma. We determined whether maternal obesity is associated with increased risk of wheezing phenotypes early in life. METHODS: We used data on 1107 mother-child pairs from two birth cohorts from the INMA-INfancia y Medio Ambiente project. Maternal height was measured and prepregnancy weight self-reported at enrolment (on average at 13.7 ± 2 weeks of gestation). Maternal prepregnancy body mass index was categorised as underweight, normal, overweight and obese according to WHO recommendations. Information on child's wheezing was obtained through questionnaires up to the age of 14 (± 1) months. Wheezing was classified as infrequent (<4 reported wheezing episodes) or frequent (≥ 4 episodes). Weight and length of infants were measured by trained study staff at 14.6 (± 1) months of age and weight-for-length z-scores computed. RESULTS: Although maternal obesity did not increase the risk of the child to have any or infrequent wheezing, children of obese mothers were more likely to have frequent wheezing than children of normal-weight mothers (11.8% vs. 3.8%; P = 0.002). In fully adjusted multinomial logistic regression models, including infants' weight-for-length z-scores and other covariates, maternal prepregnancy obesity was associated with increased risk of frequent [adjusted relative risk (RR) 4.18, 95% confidence interval (CI) 1.55, 11.3] but not infrequent (RR 1.05 [95% CI 0.55, 2.01]) wheezing in their children. CONCLUSIONS: Maternal prepregnancy obesity is independently associated with an increased risk of frequent wheezing in the infant by the age of 14 months. These findings add evidence on the potential effects of in utero exposures on asthma-related phenotypes.

Prenatal exposure to cooking gas and respiratory health in infants is modified by tobacco smoke exposure and diet in the INMA birth cohort study.

BACKGROUND: Studies that have evaluated the association between exposure to gas appliances emissions at home with respiratory health in children obtained heterogeneous and limited results. The aim of this study is to analyze the association between the use of gas cooking at home during pregnancy and respiratory problems in children during their first year of life. METHODS: In the years 2003 through 2008 pregnant women were enrolled in 4 Spanish areas and visited in different age-points following a common protocol. Outcomes studied (from a questionnaire) were any episode of lower respiratory tract infection (LRTI), wheezing, persistent cough, chestiness and otitis. The association between exposure to gas cooking at home and respiratory outcomes was assessed using logistic regression and adjusting by confounding variables. Some potential effect modifiers (i.e. smoking, fruit and vegetables consumption) were examined. RESULTS: Among the 2003 children included in the study, a total of 731 (36.6%) had a LRTI episode, 693 (34.6%) experienced wheezing, 302 (15.5%) a persistent cough, 939 (47.4%) chestiness and 620 (31.2%) had an episode of otitis during their first year of life. Gas cookers were present in 45.5% of homes. Exposure to gas cooking in homes was not associated with respiratory outcomes Odds Ratios (OR) were close to 1 and not statistically significant. However, a positive association was found for otitis among infants whose mothers reported low intakes of fruit and vegetables during pregnancy [OR (95% CI) = 1.38 (1.01-1.9)] and also wheezing and chestiness were associated with gas cookers among those children whose mothers smoked during pregnancy. CONCLUSIONS: In susceptible subjects (those whose mothers smoke and consumed below average fruit and vegetables) we found an association between exposure to gas cooking during pregnancy and risk of wheezing, chestiness and otitis during the first year of life. But more research is needed regarding not only gas cooking and respiratory health but also the possible effect modifier role of diet and tobacco.

Swimming pool attendance, respiratory symptoms and infections in the first year of life.

UNLABELLED: We evaluated the relationship between indoor and outdoor swimming pool attendance and respiratory symptoms and infections during the first year of life. A population-based mother-child cohort study was conducted in four Spanish areas (INMA project). Study subjects were recruited at pregnancy, followed to delivery and 14 months after birth. Information on swimming pool attendance and health manifestations during the first year of life was collected at 14 months: low respiratory tract infection (LRTI), persistent cough, wheezing, atopic eczema and otitis. Odds ratios and 95 % confidence interval (OR 95 %CI) were calculated by logistic regression adjusting for confounders. Among the 2,205 babies included, 37 % reported having LRTI, 37 % wheezing, 16 % persistent cough, 22 % atopic eczema, 33 % otitis and 50 % attended swimming pools during the first year of life. Around 40 % went to outdoor pools in summer with a median cumulative duration of 7.5 h/year, and 20 % attended indoor pools with a median cumulative duration of 18 h/year. Pool attendance differed by area, season of birth and sociodemographic characteristics, and was not associated with LRTI, wheezing, persistent cough, atopic eczema or otitis. Adjusted OR of wheezing and LRTI were, respectively, 1.06 (95 %CI, 0.88-1.28) and 1.09 (0.90-1.31) for babies attending vs. babies not attending pools. Stratification by type of swimming pool, cumulative duration or parental atopy did not modify the results. CONCLUSION: No association was detected between pool attendance and LRTI, wheezing, persistent cough, atopic eczema or otitis during the first year of life in Spain.

Pre-natal exposure to dichlorodiphenyldichloroethylene and infant lower respiratory tract infections and wheeze.

The aim of our study was to examine whether pre-natal exposure to dichlorodiphenyldichloroethylene (DDE) increases the risk of lower respiratory tract infections (LRTIs) and wheeze in infants. The study is based on a birth cohort of 1,455 mother-child pairs. Maternal serum concentrations of DDE, polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) were measured during pregnancy. Parental reports on LRTI and wheeze were obtained when children were 12-14 months old. 35.4% of children developed at least one LRTI episode and 33.6% at least one wheezing episode during their first 12-14 months of life. Median DDE, PCBs and HCB concentrations were 116.3, 113.7 and 46.4 ng · g(-1) lipid, respectively. DDE concentrations were associated with LRTI risk (relative risk (RR) per 10% increase 1.11, 95% CI 1.00-1.22), also after adjustment for PCBs and HCB. In all quartiles of DDE exposure, the risk of LRTI was increased compared with the lowest quartile, but the increase was statistically significant only in the third quartile (RR 1.33, 95% CI 1.08-1.62). No association was observed for PCBs and HCB. Results were similar for wheeze. This study suggests that pre-natal DDE exposure is associated with a higher risk of LRTI and wheeze in infants independently of exposure to other organochlorine compounds.

Maternal vitamin D status in pregnancy and risk of lower respiratory tract infections, wheezing, and asthma in offspring.

BACKGROUND: Adequate vitamin D status in mothers during pregnancy may influence the health status of the child later in life. We assessed whether maternal circulating 25-hydroxyvitamin D (25[OH]D) concentrations in pregnancy are associated with risk of lower respiratory tract infections, wheezing, and asthma in the offspring. METHODS: Data were obtained from 1724 children of the INfancia y Medio Ambiente (INMA) Project, a population-based birth cohort study. Maternal circulating 25(OH)D concentrations were measured in pregnancy (mean gestational age = 12.6 [SD = 2.5] weeks). When the child was age 1 year, parents were asked if their child had a physician-confirmed history of lower respiratory tract infections or a history of wheezing. The questions about wheezing were repeated annually thereafter. Asthma was defined as parental report of doctor diagnosis of asthma or receiving treatment at the age of 4-6 years or wheezing since the age of 4 years. RESULTS: The median maternal circulating 25(OH)D concentration in pregnancy was 29.5 ng/mL (interquartile range, 22.5-37.1 ng/mL). After multivariable adjustment, there was a trend for an independent association between higher levels of maternal circulating 25(OH)D levels in pregnancy and decreased odds of lower respiratory tract infections in offspring (for cohort- and season-specific quartile Q4 vs. Q1, odds ratio = 0.67 [95% confidence interval = 0.50-0.90]; test for trend, P = 0.016). We found no association between 25(OH)D levels in pregnancy and risk of wheezing at age 1 year or 4 years, or asthma at age 4-6 years. CONCLUSIONS: Higher maternal circulating 25(OH)D concentrations in pregnancy were independently associated with lower risk of lower respiratory tract infections in offspring in the first year of life but not with wheezing or asthma in childhood.

Maternal sleep duration and neonate birth weight: A population-based cohort study.

OBJECTIVE: To investigate the association between maternal sleep duration (an important health indicator) and neonate birth weight. METHODS: The study included 2536 mother-neonate pairs of a Spanish birth cohort (2004-2006, INMA project). The exposures were questionnaire-based measures of sleep duration before and during pregnancy. The primary outcome was neonate birth weight score (g) standardized to 40 weeks of gestation. RESULTS: In women sleeping for <7 h/day before pregnancy, each additional hour of sleep increased birth weight score by 44.7 g (P = 0.049) in the minimally adjusted model, although findings were not statistically significant after considering other potential confounders (P > 0.05). However, increasing sleep duration for the group of mothers who slept for more than 9 h/day decreased birth weight score by 39.2 g per additional hour (P = 0.001). Findings were similar after adjusting for several sociodemographic confounders and maternal depression-anxiety clinical history as an intermediate factor. Similar but attenuated associations were observed with sleep duration in the second trimester of pregnancy. CONCLUSION: The relationship between maternal sleep duration before and during pregnancy and neonate birth weight is an inverse U-shaped curve. Excessive sleep duration may adversely affect neonate health through its impact on birth weight.

DDE in mothers' blood during pregnancy and lower respiratory tract infections in their infants.

BACKGROUND: Dichlorodiphenyldichloroethylene (DDE) and other organochlorines suppress immunity biomarkers in animals and humans. Our aim was to study the association between prenatal levels of DDE and lower respiratory tract infection in infants independently from polychlorinated biphenyls (PCBs) and other organochlorines. METHODS: Maternal levels of p'p'-DDE, dichlorodiphenyltrichloroethane (p'p-DDT), PCB congeners 28, 118, 138, 153, and 180, hexachlorobenzene, and beta-hexachlorocyclohexane were measured in first trimester serum of 584 pregnant women from a general population-based cohort in Sabadell (Catalonia, Spain). Mothers reported lower respiratory tract infection in interviewer-led questionnaires administered at infant age 6 and 14 months. RESULTS: Thirteen percent of babies had recurrent lower respiratory tract infection during the first 14 months of life. Among the organochlorines, DDE showed the highest levels (median = 112 ng/g lipid); dichlorodiphenyltrichloroethane was not detectable. The median total PCB level was 85 ng/g. DDE was the only organochlorine that showed an association with recurrent lower respiratory tract infection (at levels >83 ng/g, the first tertile, relative risk = 2.40 [95% confidence interval = 1.19-4.83]), lower respiratory tract infection at 6 months (1.68 [1.06-2.66]), and lower respiratory tract infection at 14 months (1.52 [1.05-2.21]). Adjusting for PCBs, hexachlorobenzene or beta-hexachlorocyclohexane did not confound the association. CONCLUSIONS: Immunologic suppression by DDE as observed in experimental studies could explain the relation between DDE and lower respiratory tract infection, independently of PCBs. Exposure to DDE during prenatal life could be critical for the development of the immune and respiratory systems.