Lead contents in the surface enamel of primary and permanent teeth, whole blood, serum, and saliva of 6- to 8-year-old children

This study aimed to evaluate associations of Pb-enamel values determined in two successive enamel microbiopsies taken from a primary and a permanent tooth, and to assess how Pb-enamel correlates with Pb-blood and Pb-serum as well as whole (Pb-whole-saliva), submandibular/sublingual (Pb-sub-saliva) and parotid saliva (Pb-parotid-saliva). The study population included 444 children aged 6 to 8 years attending 4 government schools in the district of Campos Eliseos, in Ribeirao Preto, Sao Paulo State, Brazil. Whole blood, serum, parotid, submandibular/sublingual (“sub-saliva”), and whole saliva were collected in trace element-free tubes. Two successive microbiopsies were taken from the surface of a primary and a permanent tooth of each child. Lead concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS). There was a significant correlation between primary and permanent teeth in terms of Pb-enamel, for both the first and the second microbiopsies. When the median Pb-enamel values were compared between the two genders using only the highest 10th percentile Pb-enamel, there was a significant difference between girls and boys for both primary (474.2 vs 910.0 μg/g, respectively; p = 0.02) and permanent teeth (739.5 vs 1325 μg/g, respectively; p = 0.04). There were no significant correlations between Pb-enamel and Pb-blood or between Pb-enamel and lead in the 3 different salivas. However, there was a statistically significant correlation between Pb-enamel and Pb-serum when only the highest 10th percentile Pb-enamel was analyzed (r = 0.57 and p = 0.0002 for primary teeth; r = 0.56 and p < 0.0001, for permanent teeth). In conclusion, our findings have demonstrated a significant correlation between Pb-enamel found in primary and permanent teeth, as well as a significant correlation between Pb-serum and lead in primary and permanent tooth enamel. Boys presented higher Pb-enamel than girls. Our study also suggests that Pb-enamel has no correlation with Pb-blood or with lead in the 3 different salivas.     

Association between blood lead levels (< 5 μg/dL) and inattention-hyperactivity and neurocognitive profiles in school-aged Korean children

Objectives

The association between low blood lead levels (< 5 μg/dL) and the inattention-hyperactivity symptoms and neurocognitive profiles of school-aged Korean children was investigated.

Methods

We measured blood lead levels in 256 Korean children aged 8-10 years. Teachers completed the Attention-Deficit Hyperactivity Disorder Rating Scale (T-ARS)-IV to assess inattentive and hyperactive symptoms. Parents completed the Korean version of the Learning Disability Evaluation Scale (K-LDES). Children performed neurocognitive tests [The Continuous Performance Test (CPT), the Children's Color Trails Test, and the Stroop Color and Word Test (SCWT)].

Results

A linear regression analysis indicated that the blood lead concentrations were associated with the inattention scores [B = 4.8, S.E. = 1.6, 95% confidence interval (CI): 1.5-8.0], the hyperactivity subscores (3.1, 1.4, 0.3-5.9), and the total score (7.9, 2.9, 2.1-13.6) on the T-ARS; the number of omission errors on the CPT (20.6, 7.1, 6.5-34.6); the listening (−1.4, 0.7, −2.8 to −0.1), reading (−2.1, 0.7, −3.4 to −0.7), writing (−2.0, 0.7, −3.4 to −0.6), spelling (−2.2, 0.7, −3.7 to −0.7), and calculating (−1.8, 0.7, −3.1 to −0.4) scores on the K-LDES; and the color-word score on the SCWT (−6.7, 3.4, −13.3 to −0.1). A logistic regression analysis indicated that the probability of inattentive and hyperactive symptoms was increased with higher blood lead levels in boys with an odds ratio of 2.768 [B = 1.018, S.E. = 0.487, p = 0.036, 95% CI: 1.066-7.187].

Conclusion

This study suggests that even low blood lead levels (< 5 μg/dL) are associated with inattentive and hyperactivity symptoms and learning difficulties in school-aged children.     

Blood lead level and its relationship to certain essential elements in the children aged 0 to 14 years from Beijing, China

Objective

To investigate blood lead level and its relationship to copper, zinc, calcium, magnesium and iron in the children aged 0 to 14 years old from Beijing, China.

Methods

We classified 3181 children into one of the four groups: Group A (n = 783, < 1 year old); Group B (n = 1538, 1-3 years old); Group C (n = 443, 3-7 years old); and, Group D (n = 417, 7-14 years old). All these metal elements were determined by atomic absorption spectrometry.

Results

The blood lead level was 0.207 ± 0.105 μmol/L. There was a significant gender difference for zinc (P < 0.05) in Group C, and there was also a significant gender difference for copper (P < 0.05) and lead (P < 0.05) in Group D. Controlling for gender and age, we observed that there was a negative correlation of lead with zinc (r = − 0.052, P < 0.01), magnesium (r = − 0.042, P < 0.05) and iron (r = − 0.031, P < 0.05), respectively. Furthermore, in the children aged 1-7 years old, we also found there was a negative linear correlation of lead with zinc, magnesium and iron, respectively (P < 0.01).

Conclusion

Blood lead level in children from Beijing was markedly decreased. And deficiency of zinc, magnesium and iron is related to the elevated blood lead level in the children aged 1-7 years.     

Changing blood lead levels and DNA damage (comet assay) among immigrant women in Taiwan

Background

International marriage has had a rapid growth in recent years in Taiwan. However, little is known about the blood lead levels and DNA damage levels among immigrant women from resource-limited countries.

Objective

This study (a) explored differences between immigrant women and native women in demographic characteristics, blood lead levels, and DNA damage levels, and (b) identified risk factors that are associated with blood lead concentrations and DNA damage levels after immigration.

Methods

We used a structured questionnaire to collect data on socio-demographic status from (a) 71 immigrant women who had resettled in 2006 in Taichung, Taiwan and (b) 83 native women who live in the same area. Each study participant provided blood samples for lead and metal measurements, complete blood count examination, and the comet assay to measure degree of DNA damage.

Results

Immigrant women had higher mean blood lead concentration (2.23 ± 1.63 vs. 1.63 ± 1.00 μg/dl; p = 0.04) and lower mean blood zinc level (6.22 ± 2.22 vs. 6.89 ± 2.44 mg/l; p = 0.07) than native women. Resettlement time was a determinant to decrease blood lead and DNA damage levels among immigrants in Taiwan. Multiple linear regression analysis confirmed a statistically significant association between blood lead level and DNA damage, while zinc had a protective effect.

Conclusions

Public health agencies should focus on primary prevention and providing screening programs for this vulnerable population. An immigrant women's cohort should been established to follow-up and improve for elevated lead exposure families.     

Heavy metal exposure in patients suffering from electromagnetic hypersensitivity

Background

Risks from electromagnetic devices are of considerable concern. Electrohypersensitive (EHS) persons attribute a variety of rather unspecific symptoms to the exposure to electromagnetic fields. The pathophysiology of EHS is unknown and therapy remains a challenge.

Objectives

Heavy metal load has been discussed as a potential factor in the symptomatology of EHS patients. The main objective of the study was to test the hypothesis of a link between EHS and heavy metal exposure.

Methods

We measured lead, mercury and cadmium concentrations in the blood of 132 patients (n = 42 males and n = 90 females) and 101 controls (n = 34 males and n = 67 females).

Results

Our results show that heavy metal load is of no concern in most cases of EHS but might play a role in exceptional cases.

Conclusions

The data do not support the general advice to heavy metal detoxification in EHS.     

Urinary 1-hydroxypyrene and PAH exposure in 4-year-old Spanish children

Aims:

Exposure to polycyclic aromatic hydrocarbons (PAH), among the main compounds present in polluted urban air, is of concern for children's health. Childhood exposure to PAH was assessed by urinary monitoring of 1-hydroxypyrene (1-OHP), a pyrene metabolite, investigating its association with exposure to air pollution and other factors related to PAH in air.

Methods:

A group of 174 4-year-old children were recruited and a questionnaire on their indoor and outdoor residential environment was completed by parents. At the same time, environmental measurements of traffic-related air pollution (NO₂) were carried out. A urine sample was collected from each child in order to analyze 1-OHP using HPLC with fluorescence detection, correcting for creatinine concentrations. Non-parametric tests and regression analyses were used to identify environmental factors that influence 1-OHP excretion.

Results:

Mean urinary 1-OHP concentration was 0.061 μmol/mol creatinine, ranging from 0.004 to 0.314 μmol/mol. Non-parametric tests and regression analysis showed positive and significant associations (P ≤ 0.05) between 1-OHP and predicted residential exposure to NO₂ (which was based on outdoor environmental measurements and geo-statistical analysis), self-reported residential vehicle traffic, passive smoking and cooking appliance. 1-OHP levels tended to be higher among children living in urban areas (0.062 μmol/mol vs. 0.058 μmol/mol for children living in rural areas) but differences were not significant (P = 0.20).

Conclusion:

In Southern Spain, concentrations of urinary 1-OHP were in the lower range of those generally reported for children living in non-polluted areas in Western Europe and the USA. Traffic-related air pollution, passive smoking and cooking appliance influenced urinary 1-OHP level in the children, which should be prevented due to the health consequences of the inadvertent exposure to PAH during development.     

Community response to environmental noise and the impact on cardiovascular risk score

Objective

The objective of our study was to investigate and evaluate the relationship between road traffic noise and cardiovascular risk.

Methods

The study sample (n = 659; 36.9% male, 63.1% female university students, mean age 22.83 ± 1.58 years) included a group exposed to road traffic noise (n = 280, L_eq,24 h = 67 ± 2 dB(A)) and a control group (n = 379, L_eq,24 h = 58.7 ± 6 dB(A)). Subjective response was determined by a validated noise annoyance questionnaire. The ten year risk of developing a coronary heart disease event was quantified as an evaluation of cardiovascular risk (SCORE60, Framingham 10-year risk estimation and projection to the age of 60, relative risk SCORE chart).

Results

Cardiovascular risk scores were significantly higher in the exposed group based on the Framingham scores projected to the age of 60, SCORE60 (AOR = 2.72 (95% CI = 1.21-6.15)) and the relative risk SCORE chart (AOR = 2.81 (1.46-5.41)).

Conclusions

These findings highlight the association between road traffic noise and cardiovascular risk.     

Blood pressure of 8-14 year old children in relation to traffic noise at home — Results of the German Environmental Survey for Children (GerES IV)

Objectives

The German Environment Agency carried out its fourth German Environmental Survey (GerES IV) from 2003 to 2006, which was especially for children. 1048 children, 8-14 years of age, were randomly selected from all over Germany. The sample is representative of children in this age group living in Germany with respect to gender, community size, and region.

Methods

Blood pressure was measured under standardized conditions at clinical study centers. During home visits the children and their parents were asked about leisure activities, housing conditions and environmental factors, including traffic exposure of their homes. Orientating short-term noise measurements were carried out in front of the children's (bed-) room to validate the subjective ratings of the traffic volume (categories: no street, low, moderately, high/extremely high).

Results

With respect to the subjective rating of “type of street” (traffic volume) the lowest blood pressure readings were found in children whose room was facing a street with ‘low traffic’. The highest readings were found in the group where the children's rooms were facing a street with a ‘high or extremely high traffic’ volume. The difference between the two groups was 1.8 mm Hg (95% CI: 0.1 to 3.5, p = 0.036) for systolic and 1.0 mm Hg (95% CI: − 0.4 to 2.4, p = 0.148) for diastolic blood pressure. With respect to the short-term noise measurements, significant blood pressure increases of 1.0 mm Hg (95% CI: 0.3 to 1.6, p = 0.004) and 0.6 mm Hg (95% CI: 0.1 to 1.2, p = 0.025), respectively, were found per 10 dB(A) increment of the noise level.

Conclusions

The results show that road traffic noise at home is a stressor that could affect children's blood pressure.     

Blood total mercury and fish consumption in the Korean general population in KNHANES III, 2005

Objectives

The obejective of this study was to assess the association between the blood total mercury concentration and fish consumption in the Korean general adult population using a representative sample.

Methods

We studied the blood mercury concentration in a representative sample of 1,749 Koreans who were included in the Third Korean National Health and Nutritional Examination Survey (KNHANES III) performed in 2005, and compared it with the frequency of fish consumption collected during the nutrition survey of KNHANES III.

Results

The geometric means of the blood mercury levels in female subjects (n = 890), male subjects (n = 859), and all participants (n = 1,749) representing adult Koreans aged ≥ 20 years were 3.70 μg/L [95% confidence interval (CI), 3.46-3.94 μg/L], 4.70 μg/L (95% CI, 4.38-5.02 μg/L), and 4.15 μg/L (95% CI, 3.93-4.38 μg/L), respectively. The geometric mean of the blood mercury level was significantly higher in the high-fish-consumption group (4.38 μg/L; more than once a week) than in the low-consumption group (3.71 μg/L: less than once a week), but the intergroup difference of 18% was less than that in Western countries. Among the nine listed individual types of fish and shellfish, there was a general trend for the blood mercury level to increase with the consumption frequency of squid, clam, salted seafood, and mackerel. The proportion of Korean women aged 20-49 years having blood mercury levels of at least 5.8 μg/L was 27.7% (150/542) in our study.

Conclusions

The blood mercury level in a representative sample of the Korean adult population was found to be associated with fish consumption in both men and women. However, a high consumption of fish increased the blood mercury level by only 18%.     

Lead exposure is associated with a delay in the onset of puberty in South African adolescent females: Findings from the Birth to Twenty cohort

Introduction

One of the suggested, yet under-researched, causes of pubertal delay is lead exposure. In South Africa blood lead levels are generally higher than in resource-rich countries. Thus the effects of lead exposure on pubertal development may be significant.

Objective

The objective of this study is to determine the association between lead exposure and pubertal development in adolescent females in the Birth to Twenty cohort (Bt20).

Methods

Bt20 is a Johannesburg based birth cohort study that commenced in 1990 and includes 1682 girls. At 13 years of age venous blood samples were collected from 725 adolescent female participants for lead content analyses; of these, 712 had menarche data. Pubertal measurement was based on age of menarche and self-reported Tanner staging for pubic hair (n = 684) and breast development (n = 682).

Results

The mean blood lead level for the sample was 4.9 μg/dl. Fifty percent had blood lead levels < 5.0 μg/dl, 49% were ≥ 5.0 μg/dl and 1% was > 10.0 μg/dl. The average age of menarche was 12.7 years. At 13 years, 4% and 7% had reached Tanner stage 5 for pubic hair and breast development, respectively. Analyses showed that higher blood lead levels were associated with significant delays in the onset of puberty (p < 0.001).

Conclusion

The study found that higher blood lead levels were associated with a delay in the onset of puberty, after adjustment for confounders. Lead exposure in resource-poor countries is generally higher compared to resource-rich countries and thus the effects of high blood levels have personal and public health significance.     

Health impacts associated with the implementation of a national petrol-lead phase-out program (PLPOP): evidence from Taiwan between 1981 and 2007

Background and objective

In 1981, a petrol-lead phase-out program (PLPOP) was launched in Taiwan for the abatement of environmental lead emissions. The present study was set out to examine whether the reduction of environmental lead emissions would result in the decrease in mortality rates of various diseases based on national data between 1981 and 2007.

Method

The national mortality data were obtained from the Office of Statistics of the Taiwan Department of Health (Taiwan DOH). Standardized mortality ratios (SMRs) were calculated based on 2000 WHO world standard population. Gasoline consumptions were obtained from the Bureau of Energy.

Results

The mean blood lead levels (BLLs) had decreased dramatically from approximately 20.14 μg/dl in the leaded petrol phase to 3 μg/dl or lower in the unleaded petrol phase. From 1981 to 2007, the mortality (per 100,000 people) was decreased from 146.2 to 43.8 for cerebrovascular disease, from 85.3 to 44.4 for heart disease, from 35.4 to 6.6 for hypertensive disease, from 21.3 to 17.3 for nephrosis, and from 810.2 to 491.6 for all causes. By taking the confounders (including economic growth rate, per capita income, tobacco consumption, and medical resources) into account, the decreases in SMRs for all causes, cerebrovascular disease, and nephrosis were found to be highly correlated with the decrease in petrol lead emissions (p-values = 0.001, < 0.001, 0.020, respectively).

Conclusion

Our results clearly show that the implementation of the PLPOP was associated with a decline in mortality rates in several diseases that have been associated with lead exposure, even after adjustment for a number of relevant confounders.     

Prenatal exposure to organochlorine pesticides and TSH status in newborns from Southern Spain

Objective

To investigate the association between prenatal exposure to organochlorine pesticides (OCPs) and thyroid-stimulating hormone (TSH) levels in male newborns.

Methods

Exposure to 17 OCPs was analyzed in 220 placentas from a male birth cohort in Southern Spain, and TSH was measured in the umbilical cord blood. OCP concentrations were quantified by gas chromatography and mass spectrometry. Multivariate regression analysis was conducted to examine the association between pesticide exposure and neonatal TSH levels, adjusting for confounders.

Results

Newborn boys with higher exposure to endrin in placenta had higher odds of TSH cord blood levels ≥ 5 mU/L (80th percentile) (OR = 2.05; 95% CI = 1.01, 4.18; p = 0.05), whereas higher prenatal exposure to endosulfan-sulfate was associated with lower odds of TSH ≥ 5 mU/L (OR = 0.36; 95% CI = 0.17, 0.77; p = 0.008). A marginally significant negative association was found between TSH and hexachlorobenzene levels (β = − 0.15; 95% CI = − 0.31, 0.02; p = 0.09), and exposure to p,p′-DDE showed a marginally-significant higher odds of TSH ≥ 5 mU/L (OR = 1.32; 95% CI = 0.95, 1.83; p = 0.09). No association was found between TSH and the remaining pesticides.

Conclusions

Early exposure to certain environmental chemicals with endocrine-disruption activity may interfere with neonatal thyroid hormone status; however, the pattern of interference is not yet clearly elucidated.     

Prenatal exposure to lead in Spain: cord blood levels and associated factors

Introduction and Objective

Lead is a known neurotoxic. Fetuses and infants are very vulnerable to lead exposure, since their blood-brain barrier is not completely formed. Hence, there is an importance for monitoring of blood lead levels prenatally and during early infancy. The aim of this study is to evaluate the prenatal exposure to lead and its association with maternal factors in four population based mother-child cohorts in Spain. The present research was carried out within the framework of the INMA project INfancia y Medio Ambiente (Environment and Childhood).

Methods

A total of 1462 pregnant women were recruited between 2004 and 2008. Lead was analyzed in a sample of cord blood by thermal decomposition, amalgation, and Atomic Absorption Spectrometry. Maternal sociodemographic, lifestyle and dietary factors were obtained by questionnaires during pregnancy. A multivariate logistic regression model was constructed. The dependent variable was a dichotomous lead level variable (detected vs no detected, i.e. ≥ vs < 2 μg/dL).

Results

A low percentage of cord blood samples with lead levels ≥ 2 μg/dL were found (5.9%). Geometric mean and maximum were 1.06 μg/dL and 19 μg/dL, respectively. Smoking at the beginning of pregnancy, age, social class, weight gain during pregnancy, gravidity, and place of residence were the maternal factors associated with detectable cord blood lead levels. Mother's diet does not appear to be a determining factor of lead exposure. Nevertheless, daily intake of iron and zinc may act as a protective factor against having cord blood lead levels ≥ 2 μg/dL.

Conclusion

In the different regions of Spain taking part in this study, lead levels to which newborns are exposed are low. Mobilization of lead from bones may be the main contributor to the cord blood levels.     

Total blood mercury, plasma homocysteine, methylmalonic acid and folate in US children aged 3-5 years, NHANES 1999-2004

Background

Mercury is a known neurotoxicant; however, the relationship between childhood exposures and neurodevelopmental outcomes is uncertain, and may be modified by nutrition-related susceptibilities. In vitro studies found that mercury inhibited methionine synthase, an enzyme that interacts with vitamin B-12 and folate to regenerate the amino acid methionine from homocysteine, and inhibition of methionine synthase diverted homocysteine to cysteine and glutathione synthesis. The relationships between mercury, homocysteine, B-12, and folate have not been examined in children.

Objective

This study aimed to evaluate associations between Hg and homocysteine in male and female children differentiated by higher and lower methylmalonic acid (MMA, an indicator of vitamin B-12 deficiency) and folate status.

Design

Cross-sectional data on total blood mercury (Hg), plasma homocysteine, MMA, and serum folate were obtained from the 1999-2004 National Health and Nutrition Examination Surveys for children aged 3-5 years (n = 1005). We used multiple linear regression to evaluate relationships between homocysteine and Hg quartiles, stratified by sex, MMA ≥ and folate < sample medians, adjusted for demographic, anthropometric, and environmental factors.

Results

In boys with higher MMA and lower folate (n = 135), but not in other children, we observed inverse associations between homocysteine and Hg. Children with Hg > 3.49 μmol/L showed 1.14 μmol/L lower homocysteine (p < 0.001) relative to the lowest quartile (≤ 0.70 μmol/L) {p-value for trend < 0.001}. Compared to other subsamples, this subsample had significantly higher homocysteine levels.

Conclusion

Hg was inversely correlated with plasma homocysteine in young boys, but not girls, with higher MMA and lower folate. Additional studies are merited to evaluate Hg and amino acid metabolism in susceptible children.     

Exposure to polycyclic aromatic hydrocarbons and missed abortion in early pregnancy in a Chinese population

Background

Polycyclic aromatic hydrocarbons (PAHs) are formed during incomplete burning of fossil fuels, wood, and tobacco products. High PAH exposure has been associated with low birth weight, intrauterine growth restriction, and preterm birth, but little is known about its impact on adverse outcomes in early pregnancy such as in-utero fetal death.

Objectives

To examine associations between exposure to PAHs and missed abortion in which the embryo has died but a miscarriage has not yet occurred during early pregnancy in a Chinese population in Tianjin.

Methods

A case-control study was conducted from April to November, 2007 in Tianjin, China. Cases experienced a missed abortion while controls underwent elective abortions before 14 weeks of pregnancy. Eighty-one cases were recruited from four hospitals, with the same number of controls matched on hospital, maternal age (± 8 years), gravidity (1 or >1), and gestational age (± 30 days). Two maternal measures of PAH exposures were obtained based on benzo[a]pyrene (BaP) DNA adducts in 1) aborted tissues and 2) maternal blood (for a subset of subjects). In addition, proxy measures for PAH exposures from different sources were derived from maternal interviews.

Results

In conditional logistic regression analyses, we estimated more than 4-fold increase in risk of having experienced a missed abortion in women with above the median levels of blood BaP-DNA adducts (adjusted OR = 4.27; 95% CI, 1.41-12.99); but no increase with adduct levels in aborted tissues (adjusted OR = 0.76; 95% CI, 0.37-1.54). BaP-DNA adduct levels in maternal blood and aborted tissues were poorly correlated (r = − 0.12; n = 102). Missed abortion risk also was higher among women reporting traffic congestion near the residence, commuting by walking, and performing regular cooking activities during pregnancy.

Conclusion

High levels of maternal PAH exposures may contribute to an increased risk of experiencing a missed abortion during early pregnancy.     

Exposures to PM₂.₅ components and heart rate variability in taxi drivers around the Beijing 2008 Olympic Games

Background

Carbonaceous and metallic components of particles have been shown to play a role in particles' effects on cardiac autonomic function as measured by heart rate variability (HRV). Previously we reported the association of HRV with marked changes in traffic-related particulate air pollution around the Beijing 2008 Olympic Games in a panel of taxi drivers.

Objective

We further investigated the relationship between exposures to the carbonaceous and metallic components of traffic-related particles and HRV in the same population.

Methods

Repeated measurements of in-car exposures to particulate matter ≤ 2.5 μm in aerodynamic diameter (PM_2.5), carbon monoxide and nitrogen oxides were conducted in a group of 14 taxi drivers for one work shift in four study periods around the Beijing 2008 Olympics. The quantities of organic/elemental carbons and 27 elements of the in-car PM_2.5 mass were determined laboratorially. Linear mixed-effects models were used to evaluate the impact of exposures to different PM_2.5 components on HRV while controlling for potential confounders.

Results

Taxi drivers' exposures to in-car PM_2.5 and its components showed dramatic changes across the four study periods around the Beijing 2008 Olympics. Differences in associations of in-car PM_2.5 components with HRV were found. An interquartile range (IQR: 917.9 ng/m³) increase in calcium was associated with a 5.48 millisecond [ms, 95% confidence interval (CI): 0.71, 10.24] increase in standard deviations of normal-to-normal (SDNN) intervals, while an IQR (4.1 ng/m³) increase in nickel was associated with a 1.53 ms (95% CI: 0.14, 2.92) increase in SDNN index. Additionally, a decline of 8.11 ms (95% CI: − 15.26, − 0.97) in SDNN per IQR (481.4 ng/m³) increase in iron was also found.

Conclusion

The results support associations of PM_2.5 metallic components with HRV in younger healthy individuals. Future studies are needed to clarify the interaction among different PM_2.5 components or the role of PM_2.5 mixtures.     

Sensitization to profilin in the Central region of Portugal

Background

Profilin is a panallergen found in pollens and fruits. Sensitization to this protein may explain some sensitization to multiple pollen species. We aimed to evaluate sensitization to profilin in patients suffering from respiratory allergy sensitized to pollens, in the Central region of Portugal.

Methods

Patients were evaluated for asthma symptoms, rhinitis, conjunctivitis and food allergy. Skin prick tests (SPT) to aeroallergens including 12 different pollens and profilin (nPho d 2) were performed. The patients were divided into two study groups according to the region of residence: A — inland region and B — coastal region.

Results

A total of 370 patients were evaluated (277-group A; 93-group B). 65.9% showed positive skin prick tests and 76.2% were positive to pollens (87.1%-group A; 42.85%-group B; p < 0.0001). All the patients sensitized to pollens had rhinitis (p = 0.001). Sensitization to profilin was associated with pollen sensitization (p = 0.014). 43 patients were sensitized to profilin (40-group A; 3-group B; p = 0.006). 21.0% of patients sensitized to pollens, were also sensitized to profilin. 39 patients were sensitized to at least two pollens (p < 0.0001). Four profilin and pollen sensitized patients had oral allergy syndrome complaints to melon. This syndrome was related with profilin sensitization (p = 0.001).

Conclusions

It is advisable to perform SPT to profilin, particularly in the Inland region, for a better differential diagnosis between cross-reactivity and true sensitization to pollens. The results together with the medical history may support the choice for a specific immunotherapy option.     

Perinatal lead and mercury exposure in Austria

Objective

The heavy metals lead (Pb) and mercury (Hg) are ubiquitous environmental pollutants with high neurotoxic potential. We aimed to compare perinatal Pb and Hg concentrations and to explore the potential association between Pb and Hg exposure and newborn anthropometry.

Study design

Pregnant women were recruited in 2005 at the General Hospital Vienna for participation in this longitudinal study. Pb and Hg concentrations were measured in maternal blood and hair, placenta, cord blood, meconium, and breast milk of 53 mother-child pairs by CV-AAS, GF-AAS, and HPLC-CV-ICPMS. We conducted bivariate analyses and categorical regression analysis (CATREG) to evaluate the determinants of Pb and Hg exposure, and of infant anthropometry.

Results

Median Pb and total Hg contents were low, i.e., 25 μg/L (maternal blood-Pb), 13 μg/L (cord blood-Pb), 0.7 μg/L (maternal blood-Hg), and 1.1 μg/L (cord blood-Hg). Hg levels in maternal and fetal tissues were frequently correlated (r > 0.3, P < 0.05, respectively). Regarding Pb, only maternal blood and cord blood concentrations correlated (P = 0.043). Cord blood levels indicated higher Hg exposure but lower Pb exposure relative to maternal blood contents. Adjusted CATREG models indicated the significant predictors of birth length (placenta-Pb, gestational length, meconium-Pb), birth weight (placenta-Pb, gestational length, maternal blood-Pb), and head circumference (maternal education, maternal height). Besides one significant correlation between maternal hair Hg and birth length, the mercury levels were not associated with newborn anthropometry.

Conclusions

Our data implicate that different modes of action may exist for placentar transfer of Pb and Hg as well as that low Pb exposure levels can result in lower birth weight. The findings related to newborn anthropometry need to be confirmed by the examination of larger study groups. Further research is needed to clarify the mechanisms of Pb and Hg transfer via the placenta, and to explore how prenatal Pb exposure is related to intrauterine growth.     

Risk of limb birth defects and mother's home proximity to cornfields

Background

Although previous studies have linked proximity to crops and birth defects, they lacked individual-level exposure data and none was based on using planted area instead of linear proximity to crops as the exposure metric. We studied birth defects in relation to the area of corn or soybeans within 500 m of the mother's residence.

Methods

We selected all singleton births from rural areas conceived during the 2000-2004 spring-summer months (n = 48,216). We determined whether the area with corn or soybeans around the home was associated with birth defects using multiple unconditional logistic regression.

Results

We found that limb birth defects (ICD-9-CM 754.5, 755) increased in relation to cornfields (Adjusted OR = 1.22; 95 % CI = 1.01, 1.47 per additional 10 ha planted with corn within 500 m). None of the birth defect types studied was associated with soybeans.

Conclusions

In the Midwest, a significant and expanding proportion of the population is now living in close proximity to cornfields. Our results suggest that additional studies should be conducted to identify which factor(s) associated with cornfields are behind the observed increase in limb birth defects.     

Maternal exposure to floricultural work during pregnancy, PON1 Q192R polymorphisms and the risk of low birth weight

Background

Although there is evidence from animal studies of impaired reproductive function by exposure to organophosphates (OP), the effects on birth weight have not been sufficiently evaluated in epidemiological studies. Paraoxonase (PON1) detoxifies organophosphates by cleavage of active oxons. Some PON1 gene polymorphisms could reduce the enzyme activity and increase susceptibility to OP toxicity.

Objective

To assess the association between maternal exposure to floriculture during pregnancy and the risk of low birth weight (< 2500 g) in their offspring, as well as to evaluate the interaction between this exposure and maternal genotype for PON1 Q192R polymorphisms.

Materials and methods

A cross sectional study was carried out in two Mexican states (States of Mexico and Morelos) with high frequencies of greenhouse activity. We interviewed and collected blood samples from 264 females (floriculturists or partners of floricultural workers) who became pregnant during the 10 years prior to the interview. The questionnaire measured socioeconomic characteristics, tobacco and alcohol consumption, diseases and occupational and reproductive history. We also applied a food frequency questionnaire. Information was obtained pertaining to 467 pregnancies. DNA was extracted from white cells, and PON1 genotype was determined by Restriction Fragment Length Polymorphism for Q192R polymorphisms. Results were analyzed with generalized estimating equations models.

Results

After adjusting for potential confounders, we detected a statistically significant interaction between maternal exposure to flower growing work during pregnancy and PON1 Q192R polymorphisms on risk of low birth weight. The risk of having a baby with LBW is nearly six times higher if a mother is a floriculture worker during pregnancy and has PON1 192RR genotype (OR 5.93, 95% CI 1.28, 27.5).

Conclusion

These results suggest that the interaction between maternal floriculture work during pregnancy and 192RR PON1 genotype increases the probability of having children with LBW.