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.     

Characterization of road traffic noise exposure and prevalence of hypertension in central Taiwan

Epidemiological studies have demonstrated that road traffic noise exposure is associated with hypertension in European, but the associations related to traffic sources and in other population are unclear. This study investigated the association between road traffic noise exposure and the prevalence of diagnosed hypertension among 321 male and 499 female resided near main roads in Taichung, Taiwan. Road traffic noise levels and traffic flow rates were measured simultaneously during 0900-1700 on weekdays in 2008. Multivariate logistic regressions were applied to estimate odds ratios (ORs) for hypertension by adjusting for potential confounders. Road traffic noise levels were significantly associated with traffic flow rates of motorcycles, light-duty gasoline vehicles, light-duty diesel trucks and heavy-duty diesel trucks and had the highest correlation with motorcycles. Per one unit (vehicle per hour) increase in the log-transformed traffic flow rate of motorcycles was significantly related to the increment of 7.20 ± 1.40 A-weighted decibels (dBA) in the traffic noise exposure. The high-exposure group (82.2 ± 1.7 dBA, n = 358) had the significantly higher prevalence of hypertension (adjusted OR = 2.15, 95% CI = 1.08-4.26) than the low-exposure group (77.2 ± 1.6 dBA, n = 462). There was an increasing trend (p = 0.023) between the prevalence of hypertension and residents exposed to < 77 dBA, 77-80 dBA, 80-83 dBA and ≥ 83 dBA, respectively. Such an association was pronounced after adjusting for the total traffic flow rate. The study findings suggest that road traffic noise exposure may be associated with hypertension and the dominant source of traffic noise is motorcycles in central Taiwan.     

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.     

The effect of particle size on cardiovascular disorders--the smaller the worse

Background

Previous studies observed associations between airborne particles and cardio-vascular disease. Questions, however, remain as to which size of the inhalable particles (coarse, fine, or ultrafine) exerts the most significant impact on health.

Methods

For this retrospective study, data of the total number of 23,741 emergency service calls, registered between February 2002 and January 2003 in the City of Leipzig, were analysed, identifying 5326 as being related to cardiovascular incidences. Simultaneous particle exposure was determined for the particle sizes classes < 100 nm (UFP), < 2.5 μm (PM2.5) and < 10 μm (PM10). We used a time resolution of 1 day for both parameters, emergency calls and exposure.

Results

Within the group of cardiovascular diseases, the diagnostic category of hypertensive crisis showed a significant association with particle exposure. The significant effect on hypertensive crisis was found for particles with a size of < 100 nm in diameter and starting with a lag of 2 days after exposure. No consistent influence could be observed for PM2.5 and PM10. The Odds Ratios on hypertensive crisis were significant for the particle size < 100 nm in diameter from day 2 post exposure OR = 1.06 (95%CI: 1.02-1.10, p = 0.002) up to day 7 OR = 1.05 (95%CI 1.02-1.09, p = 0.005).

Conclusion

Ultrafine particles affect cardiovascular disease adversely, particularly hypertensive crises. Their effect is significant compared with PM2.5 and PM10. It appears necessary, from a public health point of view, to consider regulating this type of particles using appropriate measurands as particle number.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

Whole blood mercury and selenium concentrations in a selected Austrian population: does gender matter?

Background

Data on mercury exposure of the Austrian population were inadequate. This study was performed to determine the causal factors underlying mercury exposure and selenium concentrations, and to estimate the gender-related health impacts.

Methodology

Venous blood samples of 78 women and 81 men were drawn at the Austrian Red Cross, Vienna. Mercury contents in acid-digested whole blood samples were measured after amalgam enrichment by CV-AAS, and selenium by AAS (heated quartz-cell) after hydrid formation.

Results

The average total mercury blood content of Austrians was low (2.38 ± 1.55 μgL^− 1; N = 152). Mercury and selenium concentrations were not different between the genders (P > 0.05) but we observed discrepancies regarding the causal factors. Mercury levels in men were influenced not only by fish consumption but also by age, education level, and amalgam fillings, whereas in women, only the diet (fish/seafood, red wine consumption) determined blood mercury (P < 0.05). Moreover, only the males indicated a depressive effect of dental amalgam on hematocrit (P < 0.05). Regarding selenium, age and alcohol consumption led to lower concentrations in men, whereas a high-level education had the opposite effect; no determinant was found for women. For the whole study group, a significant effect of chronic disease on selenium levels could be detected (P < 0.05). 18% of women and 13% of men showed marginal selenium deficiency (blood selenium < 65 μgL^− 1). Selenium and mercury concentrations were not correlated.

Conclusions

Our results indicate the need to evaluate and integrate gender-related findings in metal toxicology and trace element research, because different causal factors require different preventive measures to reduce mercury exposure and the risk of low selenium concentrations. Future research is needed on the gender- and age-related differences in fish/seafood consumption habits, the modifications of mercury toxicokinetics through sex hormones, the selenium supply in Austria, and the clinical relevance of a low selenium status.     

Sub-micrometer particulate air pollution and cardiovascular mortality in Beijing, China

Background

While the link between particulate matter and cardiovascular mortality is well established, it is not fully investigated and understood which properties of the aerosol might be responsible for the health effects, especially in polluted mega-city areas.

Objectives

Our goal was to explore the association between daily cardiovascular mortality and different particle metrics in the sub-micrometer range in Beijing, China.

Methods

We obtained daily counts of cause-specific cardiovascular deaths in the Beijing urban area for the period March 2004 to August 2005. Concurrently, continuous measurements of particle number size distributions were performed. Particle number concentrations (NC) between 0.003 μm and 0.8 μm were converted to particle mass and surface area concentrations assuming spherical particles. Semi-parametric Poisson regression models adjusting for trend, seasonality, day of the week, and meteorology were used to estimate immediate, delayed and cumulative particle effects. Additionally, effect modification by air mass origin was investigated.

Results

We observed associations between daily cardiovascular mortality and particle NC for a 2-days delay. Moreover, nearly all particle metrics showed 2-days delayed associations with ischemic heart disease mortality. The strongest association was found for particle NC in the size range 0.03-0.1 μm (7.1% increase in daily mortality with a 95%-confidence interval of 2.9%-11.5%, per an increase of 6250 particles/cm³). Results for surface and mass concentrations with a lag of two days indicated effect modification by air mass origin, whereas effects of particle NC were not modified.

Conclusions

Results show an elevated risk of cardiovascular mortality in Beijing from short-term exposure to particulate air pollution in the sub-micrometer range. Results also indicate that locally produced smaller particles and regionally transported particles may exhibit different effects in Beijing.     

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%.     

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.     

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.     

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.     

The relationship between particulate air pollution and emergency hospital visits for hypertension in Beijing, China

Background

A number of epidemiological studies have examined the adverse effect of air pollution on mortality and morbidity. Also, several studies have investigated the associations between air pollution and specific-cause diseases including arrhythmia, myocardial infarction, and heart failure. However, little is known about the relationship between air pollution and the onset of hypertension.

Objective

To explore the risk effect of particulate matter air pollution on the emergency hospital visits (EHVs) for hypertension in Beijing, China.

Methods

We gathered data on daily EHVs for hypertension, fine particulate matter less than 2.5 μm in aerodynamic diameter (PM_2.5), particulate matter less than 10 μm in aerodynamic diameter (PM₁₀), sulfur dioxide, and nitrogen dioxide in Beijing, China during 2007. A time-stratified case-crossover design with distributed lag model was used to evaluate associations between ambient air pollutants and hypertension. Daily mean temperature and relative humidity were controlled in all models.

Results

There were 1,491 EHVs for hypertension during the study period. In single pollutant models, an increase in 10 μg/m³ in PM_2.5 and PM₁₀ was associated with EHVs for hypertension with odds ratios (overall effect of five days) of 1.084 (95% confidence interval (CI): 1.028, 1.139) and 1.060% (95% CI: 1.020, 1.101), respectively.

Conclusion

Elevated levels of ambient particulate matters are associated with an increase in EHVs for hypertension in Beijing, China.