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1.  Development of land use regression models for nitrogen dioxide, ultrafine particles, lung deposited surface area, and four other markers of particulate matter pollution in the Swiss SAPALDIA regions 
Environmental Health  2016;15:53.
Background
Land Use Regression (LUR) is a popular method to explain and predict spatial contrasts in air pollution concentrations, but LUR models for ultrafine particles, such as particle number concentration (PNC) are especially scarce. Moreover, no models have been previously presented for the lung deposited surface area (LDSA) of ultrafine particles. The additional value of ultrafine particle metrics has not been well investigated due to lack of exposure measurements and models.
Methods
Air pollution measurements were performed in 2011 and 2012 in the eight areas of the Swiss SAPALDIA study at up to 40 sites per area for NO2 and at 20 sites in four areas for markers of particulate air pollution. We developed multi-area LUR models for biannual average concentrations of PM2.5, PM2.5 absorbance, PM10, PMcoarse, PNC and LDSA, as well as alpine, non-alpine and study area specific models for NO2, using predictor variables which were available at a national level. Models were validated using leave-one-out cross-validation, as well as independent external validation with routine monitoring data.
Results
Model explained variance (R2) was moderate for the various PM mass fractions PM2.5 (0.57), PM10 (0.63) and PMcoarse (0.45), and was high for PM2.5 absorbance (0.81), PNC (0.87) and LDSA (0.91). Study-area specific LUR models for NO2 (R2 range 0.52–0.89) outperformed combined-area alpine (R2 = 0.53) and non-alpine (R2 = 0.65) models in terms of both cross-validation and independent external validation, and were better able to account for between-area variability. Predictor variables related to traffic and national dispersion model estimates were important predictors.
Conclusions
LUR models for all pollutants captured spatial variability of long-term average concentrations, performed adequately in validation, and could be successfully applied to the SAPALDIA cohort. Dispersion model predictions or area indicators served well to capture the between area variance. For NO2, applying study-area specific models was preferable over applying combined-area alpine/non-alpine models. Correlations between pollutants were higher in the model predictions than in the measurements, so it will remain challenging to disentangle their health effects.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0137-9) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0137-9
PMCID: PMC4835865  PMID: 27089921
SAPALDIA; Air pollution; Long term; Traffic; Particulate matter; Nanoparticles; Land use regression; LUR; NO2; PM2.5; Absorbance; PM10; Coarse fraction; PNC; LDSA
2.  The association between phthalates and metabolic syndrome: the National Health and Nutrition Examination Survey 2001–2010 
Environmental Health  2016;15:52.
Background
Higher exposure to certain phthalates is associated with a diabetes and insulin resistance, with sex differences seen. Yet, little is known about the association between phthalates and metabolic syndrome (MetS), particularly with consideration for differences by sex and menopausal status.
Methods
We analyzed data from 2719 participants in the National Health and Nutrition Examination Survey (NHANES) 2001–2010 aged 20–80 years. Five urinary phthalate metabolites (MEP, MnBP, MiBP, MBzP, and MCPP) and DEHP metabolites were analyzed by the Centers for Disease Control and Prevention and were evaluated as population-specific quartiles. MetS was defined by National Cholesterol Education Program’s Adult Treatment Panel III report criteria. Prevalence odds ratios (POR) and 95 % confidence intervals (CI) were calculated using multivariable logistic regression, adjusting for potential confounders and stratifying by sex and menopausal status.
Results
Participants with MetS (32 % of the study population) had higher concentrations for all urinary phthalate metabolites. After full adjustment, higher DEHP metabolite concentrations were associated with an increased odds of MetS in men, but not women (adj. POR for men Q4 versus Q1: 2.20; 95 % CI: 1.32, 3.68 and adj. POR for women Q4 versus Q1: 1.50; 95 % CI: 0.89, 2.52). When evaluating by menopausal status, pre-menopausal women with higher concentrations of MBzP had close to a 4-fold increased odds of MetS compared to pre-menopausal women with the lowest concentrations of MBzP (adj POR: Q4 versus Q1: 3.88; 95 % CI: 1.59, 9.49).
Conclusions
Higher concentrations of certain phthalate metabolites were associated with an increased odds of MetS. Higher DEHP metabolite concentrations were associated with an increased odds of MetS for men. In women, the strongest association was between higher concentrations of MBzP and MetS, but only among pre-menopausal women.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0136-x) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0136-x
PMCID: PMC4832560  PMID: 27079661
Phthalates; Metabolic syndrome; Blood pressure; Obesity; Cholesterol; Sex
3.  Maternal levels of endocrine disruptors, polybrominated diphenyl ethers, in early pregnancy are not associated with lower birth weight in the Canadian birth cohort GESTE 
Environmental Health  2016;15:49.
Background
Polybrominated diphenyl ethers are known endocrine disrupting environmental contaminants used as flame retardants. Their levels have increased in humans over the last ten years, raising concerns about their consequences on human health. Some animal studies suggest that PBDEs can affect fetal growth; however, the results of human studies are contradictory. This study evaluates the association between the most common PBDEs in maternal blood measured in early pregnancy and birth weight.
Methods
BDE-47, BDE-99, BDE-100 and BDE-153 levels were measured in 349 women during their first prenatal care visit at the University Hospital Center of Sherbrooke (Quebec, Canada). Birth weight and relevant medical information were collected from medical records. In contrast with previous studies, we examined the full range of clinical risk factors known to affect fetal growth as potential confounders, as well as other environmental pollutants that are likely to interact with fetal growth (polychlorinated biphenyls (PCBs), mercury, lead, cadmium and manganese).
Results
There was no statistically significant relationship between PBDE levels in early pregnancy and birth weight in both unadjusted and multivariate regression models.
Conclusions
Our results suggest that PBDEs in early pregnancy have little or no direct impact on birth weight, at least at the levels of exposure in our population.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0134-z) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0134-z
PMCID: PMC4828807  PMID: 27068391
Polybrominated diphenyl ethers; Pregnancy; Birth weight; Polychlorinated biphenyls; Mercury; Lead; Cadmium; Manganese
4.  Direct measurement of Bisphenol A (BPA), BPA glucuronide and BPA sulfate in a diverse and low-income population of pregnant women reveals high exposure, with potential implications for previous exposure estimates: a cross-sectional study 
Environmental Health  2016;15:50.
Background
Bisphenol A (BPA) is a ubiquitous, endocrine-disrupting environmental contaminant that increases risk of some adverse developmental effects. Thus, it is important to characterize BPA levels, metabolic fate and sources of exposure in pregnant women.
Methods
We used an improved liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytic method to directly and simultaneously measure unconjugated BPA (uBPA), BPA glucuronide and BPA sulfate in the urine of a population of ethnically and racially diverse, and predominately low-income pregnant women (n = 112) in their second trimester. We also administered a questionnaire on dietary and non-dietary sources of exposure to BPA.
Results
We found universal and high exposure to uBPA and its metabolites: median concentrations were 0.25, 4.67, and 0.31 μg/g creatinine for uBPA, BPA glucuronide, and BPA sulfate, respectively. The median Total BPA (uBPA + BPA in glucuronide and sulfate forms) level was more than twice that measured in U.S. pregnant women in NHANES 2005–2006, while 30 % of the women had Total BPA levels above the 95th percentile. On average, Total BPA consisted of 71 % BPA in glucuronide form, 15 % BPA in sulfate form and 14 % uBPA, however the proportion of BPA in sulfate form increased and the proportion of uBPA decreased with Total BPA levels. Occupational and non-occupational contact with paper receipts was positively associated with BPA in conjugated (glucuronidated + sulfated) form after adjustment for demographic characteristics. Recent consumption of foods and beverages likely to be contaminated with BPA was infrequent among participants and we did not observe any positive associations with BPA analyte levels.
Conclusion
The high levels of BPA analytes found in our study population may be attributable to the low-income status of the majority of participants and/or our direct analytic method, which yields a more complete evaluation of BPA exposure. We observed near-universal exposure to BPA among pregnant women, as well as substantial variability in BPA metabolic clearance, raising additional concerns for effects on fetal development. Our results are consistent with studies showing thermal paper receipts to be an important source of exposure, point to the difficulty pregnant women have avoiding BPA exposure on an individual level, and therefore underscore the need for changes in BPA regulation and commerce.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0131-2) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0131-2
PMCID: PMC4828888  PMID: 27071747
Bisphenol A; Pregnant women; Children’s environmental health; Exposure sources; Liquid chromatography-tandem mass spectrometry (LC-MS/MS)
5.  Preeclampsia and toxic metals: a case-control study in Kinshasa, DR Congo 
Environmental Health  2016;15:48.
Background
Preeclampsia is frequent in Kinshasa (Democratic Republic of Congo), especially during the dry season. We tested whether preeclampsia was associated with exposure to environmental metals.
Methods
Using a case-control design, 88 women hospitalized with preeclampsia (cases) and 88 healthy pregnant women from the antenatal clinic (controls) were included in the study; 67 and 109 women were enrolled during the rainy and dry season, respectively. The concentrations of 24 elements were quantified by inductively coupled plasma mass spectrometry (ICP-MS) in 24-h urine collections. Differences in the urinary excretion of metals were investigated between cases and controls, and the interaction with season was assessed.
Results
Cases and controls were well matched regarding age, parity and duration of pregnancy. In controls, the urinary concentrations of most elements were substantially higher than reference values for adults from industrially developed countries, e.g. for lead: geometric mean (GM) 8.0 μg/L [25th-75th percentile 3.1–13.8]. The daily urinary excretions of 14 metals were significantly higher in women with preeclampsia than in control women, e.g. for lead: GM 61 μg/day (25th–75th percentile 8–345) in women with preeclampsia vs 9 μg/day (25th–75th percentile 3–21) in controls (p < 0 · 001). A significant interaction was found between season and preeclampsia for several elements, with higher urinary excretions in preeclamptic women than controls during the dry season, but not during the rainy season.
Conclusions
This study revealed not only that women with preeclampsia excrete higher amounts of several toxic metals, especially lead, than control women, but also that this excretion exhibits seasonal variation, thus possibly explaining the high incidence and seasonal variation of preeclampsia in Kinshasa. Although the exact sources of this exposure are unknown, these findings underscore the need for preventing environmental exposures to lead and other toxic metals.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0132-1) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0132-1
PMCID: PMC4820935  PMID: 27044488
Metal pollution; Lead; Preeclampsia; Hypertension; Seasonality; Developing country; Global health
6.  Associations of air pollution exposure with blood pressure and heart rate variability are modified by oxidative stress genes: A repeated-measures panel among elderly urban residents 
Environmental Health  2016;15:47.
Background
Oxidative stress has been suggested as a major cause of elevated blood pressure (BP) and reduced heart rate variability (HRV) due to air pollution. We hypothesized that the associations of air pollution exposure with BP and HRV are modified by oxidative stress gene polymorphisms.
Methods
Between 2008 and 2010, we conducted up to 5 surveys of 547 elderly participants, measured their BP and HRV, and genotyped 47 single nucleotide polymorphisms (SNPs) in 18 oxidative stress genes. Linear mixed models were constructed to evaluate the associations of particulate matter ≤10 μm, nitrogen dioxide, and sulfur dioxide with BP and HRV, as well as the modifications of these associations by the genotyped SNPs.
Results
Single-SNP analyses revealed interactions between air pollution and 15 SNPs (for BP) and 33 SNPs (for HRV) (all, P for interaction < 0.05). When we generated genetic risk scores for BP and HRV, using the SNPs with interactions in the single-SNP models, we found that associations of air pollution exposure with BP and HRV were modified by the genetic risk scores (P for interaction < 0.05).
Conclusions
These results strongly suggest that the associations of air pollution with BP and HRV are mediated by oxidative stress pathways.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0130-3) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0130-3
PMCID: PMC4807581  PMID: 27015811
Air pollution; Heart rate variability; Blood pressure; Oxidative stress; Genetic factors
7.  Ambient PM2.5 and risk of emergency room visits for myocardial infarction: impact of regional PM2.5 oxidative potential: a case-crossover study 
Environmental Health  2016;15:46.
Background
Regional differences in the oxidative potential of fine particulate air pollution (PM2.5) may modify its impact on the risk of myocardial infarction.
Methods
A case-crossover study was conducted in 16 cities in Ontario, Canada to evaluate the impact of regional PM2.5 oxidative potential on the relationship between PM2.5 and emergency room visits for myocardial infarction. Daily air pollution and meteorological data were collected between 2004 and 2011 from provincial monitoring sites and regional estimates of glutathione (OPGSH) and ascorbate-related (OPAA) oxidative potential were determined using an acellular assay based on a synthetic respiratory tract lining fluid. Exposure variables for the combined oxidant capacity of NO2 and O3 were also examined using their sum (Ox) and a weighted average (Oxwt) based on their redox potentials.
Results
In total, 30,101 cases of myocardial infarction were included in the analysis. For regions above the 90th percentile of OPGSH each 5 μg/m3 increase in same-day PM2.5 was associated with a 7.9 % (95 % CI: 4.1, 12) increased risk of myocardial infarction whereas a 4.1 % (95 % CI: 0.26, 8.0) increase was observed in regions above the 75th percentile and no association was observed below the 50th percentile (p-interaction = 0.026). A significant 3-way interaction was detected with the strongest associations between PM2.5 and myocardial infarction occurring in areas with high regional OPGSH and high Oxwt (p-interaction < 0.001).
Conclusions
Regional PM2.5 oxidative potential may modify the impact of PM2.5 on the risk of myocardial infarction. The combined oxidant capacity of NO2 and O3 may magnify this effect.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0129-9) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0129-9
PMCID: PMC4806515  PMID: 27012244
Particulate matter; Oxidative potential; Myocardial infarction; Case-crossover
9.  Neurodevelopmental outcomes among 2- to 3-year-old children in Bangladesh with elevated blood lead and exposure to arsenic and manganese in drinking water 
Environmental Health  2016;15:44.
Background
The people of Bangladesh are currently exposed to high concentrations of arsenic and manganese in drinking water, as well as elevated lead in many regions. The objective of this study was to investigate associations between environmental exposure to these contaminants and neurodevelopmental outcomes among Bangladeshi children.
Methods
We evaluated data from 524 children, members of an ongoing prospective birth cohort established to study the effects of prenatal and early childhood arsenic exposure in the Sirajdikhan and Pabna Districts of Bangladesh. Water was collected from the family’s primary drinking source during the first trimester of pregnancy and at ages 1, 12 and 20–40 months. At age 20–40 months, blood lead was measured and neurodevelopmental outcomes were assessed using a translated, culturally-adapted version of the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III).
Results
Median blood lead concentrations were higher in Sirajdikhan than Pabna (7.6 vs.
Conclusion
Where blood lead levels are high, lead is associated with decreased cognitive scores on the BSID-III, and effects of other metals are not detected. In the setting of lower lead levels, the adverse effects of arsenic and manganese on neurodevelopment are observed.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0127-y) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0127-y
PMCID: PMC4788832  PMID: 26968381
Arsenic; Manganese; Lead; Cognitive function
Environmental Health  2016;15:42.
Background
The Sverdlovsk region of the Russian Federation is characterised by its abundance of natural resources and industries. Located in this region, Asbest city is situated next to one of the largest open-pit chrysotile asbestos mines currently operational; many city residents are employed in activities related to mining and processing of chrysotile. We compared mortality rates from 1997 to 2010 in Asbest city to the remaining Sverdlovsk region, with additional analyses conducted for site-specific cancer mortality.
Methods
Population and mortality data for Asbest city and Sverdlovsk region were used to estimate crude and age-specific rates by gender for the entire period and for each calendar year. Age-standardized mortality rates were also calculated for the adult population (20+) and Poisson regression was used to estimate standardized mortality ratios, overall and by gender.
Results
During the period of 1997 to 2010, there were similar mortality rates overall in Asbest and the Sverdlovsk region. However, there were higher rates of cancer mortality (18 % males; 21 % females) and digestive diseases (21 % males; 40 % females) in Asbest and lower rates of unknown/ill-defined in Asbest (60 % males; 47 % females). Circulatory disease mortality was slightly lower in Asbest. Cancer mortality was higher for men in Asbest from oesophageal, urinary tract and lung cancers compared to the Sverdlovsk region. In women, cancer mortality was higher for women in Asbest from stomach, colon, lung and breast cancers compared to the Sverdlovsk region.
Conclusions
This large population-based analysis indicates interesting differences but studies with individual exposure information are needed to understand the underlying factors.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0125-0) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0125-0
PMCID: PMC4772512  PMID: 26926835
Russian Federation; Mortality; Neoplasms; Asbest; Sverdlovsk region
Environmental Health  2016;15:41.
Background
Cortisol has functions on homeostasis, growth, neurodevelopment, immune function and the stress response. Secretion follows a diurnal rhythm that mediates these processes. Our objective was to examine the association between prenatal lead exposure and infant diurnal cortisol rhythms.
Methods
We measured infant cortisol rhythms in saliva collected repeatedly over 2 days at either 12 (n = 255) or 18–24 (n = 150) months of age. Prenatal lead exposure was assessed by measuring maternal pregnancy blood lead levels and early postnatal maternal bone lead content. We analyzed age-specific basal secretion and the association between trimester-specific and cumulative lead exposure with a) change in total diurnal cortisol and b) the shape of the cortisol curve across the length of the day.
Results
Our results showed age related differences in salivary cortisol secretion and an age dependent association with maternal lead exposure. In age-stratified models we saw an inverse association between lead and cortisol levels in 12-month-old infants and a positive association for 18–24-month-old infants. For the 12-month-old infants 2nd-trimester-lead ≥10 μg/dL was associated with 40 % lower cortisol levels (95 % CI (−57, −16)) and a significant change in the shape of the cortisol curve (p = 0.01), compared to infants with low blood lead levels (<5 μg/dL).
Conclusions
Basal cortisol secretion changes with age. Increased early gestation lead exposure alters diurnal cortisol rhythms and the association is modified by infant age, perhaps representing an early maturation of cortisol homeostasis.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0124-1) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0124-1
PMCID: PMC4772459  PMID: 26926653
Lead; Cortisol; Epidemiology; Prenatal
Environmental Health  2016;15:40.
Background
Rodent and human studies suggest an association between air pollution exposure and type 2 diabetes mellitus, but the extent to which air pollution is associated with gestational diabetes mellitus (GDM) is less clear.
Methods
We used the Massachusetts Registry of Vital Records to study primiparous women pregnant from 2003-2008 without pre-existing diabetes. We used satellite-based spatiotemporal models to estimate first and second trimester residential particulate (PM2.5) exposure and geographic information systems to estimate neighborhood traffic density. We obtained GDM status from birth records. We performed logistic regression analyses adjusted for sociodemographics on the full cohort and after stratification by maternal age and smoking habits.
Results
Of 159,373 women, 5,381 (3.4 %) developed GDM. Residential PM2.5 exposure ranged 1.3–19.3 μg/m3 over the second trimester. None of the exposures were associated with GDM in the full cohort [e.g. OR 0.99 (95 % CI: 0.95, 1.03) for each interquartile range (IQR) increment in second trimester PM2.5]. There were also no consistent associations after stratification by smoking habits. When the cohort was stratified by maternal age, women less than 20 years had 1.36 higher odds of GDM (95 % CI: 1.08, 1.70) for each IQR increment in second trimester PM2.5 exposure.
Conclusions
Although we found no evidence of an association between air pollution exposure and GDM among all women in our study, greater exposure to PM2.5 during the second trimester was associated with GDM in the youngest age stratum.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0121-4) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0121-4
PMCID: PMC4765142  PMID: 26911579
Air pollution; Gestational diabetes; PM2.5; Pregnancy
Environmental Health  2016;15:39.
Background
Air pollutants have been linked to type 2 diabetes (T2D), hypothesized to act through inflammatory pathways and may induce interleukin-6 gene (IL6) in the airway epithelium. The cytokine interleukin-6 may impact on glucose homeostasis. Recent meta-analyses showed the common polymorphisms, IL6 -572G > C and IL6 -174G > C to be associated with T2D risk. These IL6 variants also influence circulatory interleukin-6 levels. We hypothesize that these common functional variants may modify the association between air pollutants and T2D.
Methods
We cross-sectionally studied 4410 first follow-up participants of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases (SAPALDIA), aged 29 to 73 years who had complete data on genotypes, diabetes status and covariates. We defined diabetes as self-reported physician-diagnosed, or use of diabetes medication or non-fasting glucose >11.1 mmol/L or HbA1c > 0.065. Air pollution exposure was 10-year mean particulate matter <10 μm in diameter (PM10) assigned to participants’ residences using a combination of dispersion modelling, annual trends at monitoring stations and residential history. We derived interaction terms between PM10 and genotypes, and applied mixed logistic models to explore genetic interactions by IL6 polymorphisms on the odds of diabetes.
Results
There were 252 diabetes cases. Respective minor allele frequencies of IL6 -572G > C and IL6 -174G > C were 7 and 39 %. Mean exposure to PM10 was 22 μg/m3. Both variants were not associated with diabetes in our study. We observed a significant positive association between PM10 and diabetes among homozygous carriers of the pro-inflammatory major G-allele of IL6 -572G > C [Odds ratio: 1.53; 95 % confidence interval (1.22, 1.92); Pinteraction (additive) = 0.003 and Pinteraction (recessive) = 0.006]. Carriers of the major G-allele of IL6 -174G > C also had significantly increased odds of diabetes, but interactions were statistically non-significant.
Conclusions
Our results on the interaction of PM10 with functionally well described polymorphisms in an important pro-inflammatory candidate gene are consistent with the hypothesis that air pollutants impact on T2D through inflammatory pathways. Our findings, if confirmed, are of high public health relevance considering the ubiquity of the major G allele, which puts a substantial proportion of the population at risk for the development of diabetes as a result of long-term exposure to air pollution.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0120-5) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0120-5
PMCID: PMC4765217  PMID: 26911440
Particulate matter; Air pollution; Diabetes mellitus; Interleukin-6 gene; Gene-environment interactions; Single nucleotide polymorphisms; Cross-sectional epidemiology
Environmental Health  2016;15:26.
Background
Use of mobile (MP) and cordless phones (CP) is common among young children, but whether the resulting radiofrequency exposure affects development of cognitive skills is not known. Small changes have been found in older children. This study focused on children’s exposures to MP and CP and cognitive development. The hypothesis was that children who used these phones would display differences in cognitive function compared to those who did not.
Methods
We recruited 619 fourth-grade students (8-11 years) from 37 schools around Melbourne and Wollongong, Australia. Participants completed a short questionnaire, a computerised cognitive test battery, and the Stroop colour-word test. Parents completed exposure questionnaires on their child’s behalf. Analysis used multiple linear regression. The principal exposure-metrics were the total number of reported MP and CP calls weekly categorised into no use ('None'); use less than or equal to the median amount (‘Some’); and use more than the median (‘More’). The median number of calls/week was 2.5 for MP and 2.0 for CP.
Results
MP and CP use for calls was low; and only 5 of 78 comparisons of phone use with cognitive measures were statistically significant. The reaction time to the response-inhibition task was slower in those who used an MP ‘More’ compared to the ‘Some’ use group and non-users. For CP use, the response time to the Stroop interference task was slower in the ‘More’ group versus the ‘Some’ group, and accuracy was worse in visual recognition and episodic memory tasks and the identification task. In an additional exploratory analysis, there was some evidence of a gender effect on mean reaction times. The highest users for both phone types were girls.
Conclusions
Overall, there was little evidence cognitive function was associated with CP and MP use in this age group. Although there was some evidence that effects of MP and CP use on cognition may differ by gender, this needs further exploration. CP results may be more reliable as parents estimated children’s phone use and the CPs were at home; results for CP use were broadly consistent with our earlier study of older children.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0116-1) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0116-1
PMCID: PMC4759913  PMID: 26892106
Cognition; Reactions; Accuracy; Mobile phone; Cordless phone; Episodic memory; Spatial ability; Executive ability
Environmental Health  2016;15:19.
The broad-spectrum herbicide glyphosate (common trade name “Roundup”) was first sold to farmers in 1974. Since the late 1970s, the volume of glyphosate-based herbicides (GBHs) applied has increased approximately 100-fold. Further increases in the volume applied are likely due to more and higher rates of application in response to the widespread emergence of glyphosate-resistant weeds and new, pre-harvest, dessicant use patterns. GBHs were developed to replace or reduce reliance on herbicides causing well-documented problems associated with drift and crop damage, slipping efficacy, and human health risks. Initial industry toxicity testing suggested that GBHs posed relatively low risks to non-target species, including mammals, leading regulatory authorities worldwide to set high acceptable exposure limits. To accommodate changes in GBH use patterns associated with genetically engineered, herbicide-tolerant crops, regulators have dramatically increased tolerance levels in maize, oilseed (soybeans and canola), and alfalfa crops and related livestock feeds. Animal and epidemiology studies published in the last decade, however, point to the need for a fresh look at glyphosate toxicity. Furthermore, the World Health Organization’s International Agency for Research on Cancer recently concluded that glyphosate is “probably carcinogenic to humans.” In response to changing GBH use patterns and advances in scientific understanding of their potential hazards, we have produced a Statement of Concern drawing on emerging science relevant to the safety of GBHs. Our Statement of Concern considers current published literature describing GBH uses, mechanisms of action, toxicity in laboratory animals, and epidemiological studies. It also examines the derivation of current human safety standards. We conclude that: (1) GBHs are the most heavily applied herbicide in the world and usage continues to rise; (2) Worldwide, GBHs often contaminate drinking water sources, precipitation, and air, especially in agricultural regions; (3) The half-life of glyphosate in water and soil is longer than previously recognized; (4) Glyphosate and its metabolites are widely present in the global soybean supply; (5) Human exposures to GBHs are rising; (6) Glyphosate is now authoritatively classified as a probable human carcinogen; (7) Regulatory estimates of tolerable daily intakes for glyphosate in the United States and European Union are based on outdated science. We offer a series of recommendations related to the need for new investments in epidemiological studies, biomonitoring, and toxicology studies that draw on the principles of endocrinology to determine whether the effects of GBHs are due to endocrine disrupting activities. We suggest that common commercial formulations of GBHs should be prioritized for inclusion in government-led toxicology testing programs such as the U.S. National Toxicology Program, as well as for biomonitoring as conducted by the U.S. Centers for Disease Control and Prevention.
doi:10.1186/s12940-016-0117-0
PMCID: PMC4756530  PMID: 26883814
Glyphosate; Acceptable daily intake (ADI); AMPA; Consensus statement; Endocrine disruptor; Reference dose (RfD); Risk assessment; Roundup Ready; Toxicology
Environmental Health  2016;15:24.
Background
There is growing interest in health risks of residents living near concentrated animal feeding operations (CAFOs). Previous research mostly focused on swine CAFOs and self-reported respiratory conditions. The aim was to study the association between the presence of swine, poultry, cattle and goat CAFOs and health of Dutch neighbouring residents using electronic medical records from general practitioners (GPs).
Methods
Data for the year 2009 were collected of 119,036 inhabitants of a rural region with a high density of CAFOs using information from GIAB (high exposed population). A comparison was made with GP data from 78,060 inhabitants of rural areas with low densities of CAFOs (low exposed population). Associations between the number of CAFOs near residents’ homes and morbidity were determined by multilevel (cross-classified) logistic regression.
Results
In 2009, the prevalence of most respiratory and gastrointestinal conditions was similar in the high and low exposed population. Exceptions were pneumonia, atopic eczema and unspecified infectious diseases with an increased prevalence, and sinusitis with a decreased prevalence in the high exposed population. Within the high CAFO density region, the number of poultry, cattle and swine CAFOs near residents’ homes was not associated with allergic, respiratory or gastrointestinal conditions. Conversely, each additional goat CAFO within the postal code area of residents’ homes significantly increased the odds of unspecified infectious disease and pneumonia by 87 and 41 percent, respectively.
Conclusions
Using GP records, pneumonia and unspecified infectious diseases were positively associated with the number of goat CAFOs near residents’ homes, but no association was found between swine, cattle, and poultry CAFOs and respiratory, allergic or gastrointestinal conditions.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0123-2) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0123-2
PMCID: PMC4758110  PMID: 26888643
Livestock; Poultry; Public health; Environmental exposure; Multilevel analysis
Environmental Health  2016;15:22.
Background
Injuries involving career-technical-vocational education (CTE) are reported to the New Jersey Safe Schools Program online reporting system, the only U.S. State law-based surveillance data for young workers (ages twenty-one and younger), a susceptible, vulnerable adolescent sub-population.
Methods
We examined potential associations between socioeconomic status (SES) indicators and high school student injuries reported between 12/1998-12/2013, excluding injuries acquired by staff members. Associations between DFG score—a proxy for school/district SES—and variables relating to reported injuries, including severity, injury type, injury cause, body parts injured, injury treatment setting and demographics were examined with chi square test (X2) for independence and logistic regression. To assess potential associations between SES and personal protective equipment (PPE), data were stratified by 2003–2008 and 2008–2013, given mandated payment by employers of PPE for employees.
Results
Statistically significant associations were found between SES and injury cause [X2 = (7, 14.74), p = 0.04] and SES and injury treatment setting [X2 = (1, 4.76), p = 0.03]. Adjusted odds ratio suggested students from low SES schools were at a higher odds of being treated at a hospital emergency department (ED) than students from high SES schools (95 % CI 1.3–4.3, p < 0.01).
Conclusions
These findings indicated low SES schools/districts have increased odds of being treated at ED, after controlling for injury severity. Future research should focus on implications such associations have on health care access and insurance for young workers and their families. With small sample sizes representing lower DFG scoring (SES) schools/districts, additional efforts should be enacted to increase injury reporting in these schools/districts.
doi:10.1186/s12940-016-0118-z
PMCID: PMC4754864  PMID: 26883909
Injury; Socioeconomic status; Young workers
Environmental Health  2016;15:21.
Background
Several studies demonstrated a short-term association between ambient temperature and blood pressure. However, few studies have assessed the long-term effect of ambient temperature on children’s blood pressure. The present study aimed to investigate the association between long-term exposure to local ambient temperature and children’s blood pressure in China.
Methods
We analyzed the systolic (SBP) and diastolic blood pressure (DBP) data of 71,763 children from 2010 Chinese National Survey on Students’ Construction and Health (CHNSCH), and local annual average ambient temperature, relative humidity, air pollutants data from China Meteorological Administration and Ministry of Environment Protection of China. We used generalized additive model (GAM) with non-linear function to examine the effects of ambient temperature on children’s blood pressure.
Results
The results showed that decrease of ambient temperature was negatively associated with increase of both SBP and DBP in Chinese children while adjusting for individual characteristics, socioeconomic conditions, air pollutants and relative humidity. The largest alteration of SBP related to the temperature difference was observed from 20.4 to 9.6 °C, with 9.0 mmHg (95 % CI: 8.4, 9.5) increase in SBP, while the largest alteration of DBP was observed from 21.7 to 10.2 °C, with 6.1 mmHg (95 % CI: 5.6, 6.6) increase in DBP. However, when temperature below 9.6 and 10.2 °C, SBP and DBP started to decrease, which might be caused by the use of heating system in the extreme cold areas.
Conclusions
Public health policy should be improved for protecting children’s cardiovascular health from adverse effects of low temperature. Development of heating system in moderate cold area might be a good solution.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0119-y) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0119-y
PMCID: PMC4754880  PMID: 26880195
Ambient temperature; Blood pressure; Association; Children
Environmental Health  2016;15:23.
Background
Many populations have been exposed to environmental lead from paint, petrol, and mining and smelting operations. Lead is toxic to humans and there is emerging evidence linking childhood exposure with later life antisocial behaviors, including delinquency and crime. This study tested the hypothesis that childhood lead exposure in select Australian populations is related to subsequent aggressive criminal behaviors.
Methods
We conducted regression analyses at suburb, state and national levels using multiple analytic methods and data sources. At the suburb-level, we examined assault rates as a function of air lead concentrations 15–24 years earlier, reflecting the ubiquitous age-related peak in criminal activity. Mixed model analyses were conducted with and without socio-demographic covariates. The incidence of fraud was compared for discriminant validity. State and national analyses were conducted for convergent validity, utilizing deaths by assault as a function of petrol lead emissions.
Results
Suburb-level mixed model analyses showed air lead concentrations accounted for 29.8 % of the variance in assault rates 21 years later, after adjusting for socio-demographic covariates. State level analyses produced comparable results. Lead petrol emissions in the two most populous states accounted for 34.6 and 32.6 % of the variance in death by assault rates 18 years later.
Conclusions
The strong positive relationship between childhood lead exposure and subsequent rates of aggressive crime has important implications for public health globally. Measures need to be taken to ameliorate exposure to lead and other environmental contaminants with known neurodevelopmental consequences.
doi:10.1186/s12940-016-0122-3
PMCID: PMC4756504  PMID: 26884052
Aggressive crime; Assault; Childhood; Lead exposure; Death
Environmental Health  2016;15:20.
The ways in which humans affect and are affected by their environments have been studied from many different perspectives over the past decades. However, it was not until the 1970s that the discussion of the ethical relationship between humankind and the environment formalized as an academic discipline with the emergence of environmental ethics. A few decades later, environmental health emerged as a discipline focused on the assessment and regulation of environmental factors that affect living beings. Our goal here is to begin a discussion specifically about the impact of modern environmental change on biomedical and social understandings of brain and mental health, and to align this with ethical considerations. We refer to this focus as Environmental Neuroethics, offer a case study to illustrate key themes and issues, and conclude by offering a five-tier framework as a starting point of analysis.
doi:10.1186/s12940-016-0114-3
PMCID: PMC4754959  PMID: 26880112
Brain health; Mental health; Environment; Ethics; Social implications
Environmental Health  2016;15:16.
Background
Experimental animal studies, in vitro experiments, and clinical assessments have shown that metal toxicity can impair immune responses. We analyzed data from a United States representative National Health and Nutrition Examination Survey (NHANES) to explore associations between chronic infections and elevated blood concentrations of lead and cadmium among non-smoking NHANES participants.
Methods
NHANES data from 1999 to 2012 were examined and weighted to represent the United States population. Multivariable logistic regression was used to estimate adjusted odds ratios (AOR) and 95 % confidence intervals (CI) for heavy metal associations with seropositivity for Helicobacter pylori, Toxoplasma gondii, and Hepatitis B virus (HBV) infections.
Results
Available 2-year survey cycles for infection seroprevalence varied by pathogen, from 1 to 7 cycles. Available sample size, disease seroprevalence, and participant age range also varied by pathogen of interest. After controlling for demographic characteristics and general health condition, an elevated blood lead level above the survey population median was significantly associated with seropositivity for all three pathogens (AORs = 1.2–1.5). In addition, an elevated blood cadmium level above the median was significantly associated with HBV (AOR = 1.5; 95 % CI = 1.2–2.0) and H. pylori (AOR = 1.5; 95 % CI = 1.2–1.7) seropositivity. Age-specific analyses for H. pylori and T. gondii indicated stronger associations among children under 13 years of age, particularly for lead exposure and H. pylori seropositivity, and weaker associations among those over 35 years of age.
Conclusions
The results of this cross-sectional human health survey suggest that the immunological effects of lead and cadmium toxicity may be associated with an increased susceptibility to chronic infections.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0113-4) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0113-4
PMCID: PMC4750187  PMID: 26864738
Helicobacter pylori; Toxoplasma; Hepatitis B; Nutrition surveys; Seroprevalence; Heavy metals; Immune system; Immunomodulation
Environmental Health  2016;15:18.
Background
Understanding the shape of the relationship between long-term exposure to ambient fine particulate matter (PM2.5) concentrations and health risks is critical for health impact and risk assessment. Studies evaluating the health risks of exposure to low concentrations of PM2.5 are limited. Further, many existing studies lack individual-level information on potentially important behavioural confounding factors.
Methods
A prospective cohort study was conducted among a subset of participants in a cohort that linked respondents of the Canadian Community Health Survey to mortality (n = 299,500) with satellite-derived ambient PM2.5 estimates. Participants enrolled between 2000 and 2008 were followed to date of death or December 31, 2011. Cox proportional hazards models were used to estimate hazard ratios (HRs) for mortality attributed to PM2.5 exposure, adjusted for individual-level and contextual covariates, including smoking behaviour and body mass index (BMI).
Results
Approximately 26,300 non-accidental deaths, of which 32.5 % were due to circulatory disease and 9.1 % were due to respiratory disease, occurred during the follow-up period. Ambient PM2.5 exposures were relatively low (mean = 6.3 μg/m3), yet each 10 μg/m3 increase in exposure was associated with increased risks of non-accidental (HR = 1.26; 95 % CI: 1.19-1.34), circulatory disease (HR = 1.19; 95 % CI: 1.07–1.31), and respiratory disease mortality (HR = 1.52; 95 % CI: 1.26–1.84) in fully adjusted models. Higher hazard ratios were observed for respiratory mortality among respondents who never smoked (HR = 1.97; 95 % CI: 1.24–3.13 vs. HR = 1.45; 95 % CI: 1.17–1.79 for ever smokers), and among obese (BMI ≥ 30) respondents (HR = 1.76; 95 % CI: 1.15-2.69 vs. HR = 1.41; 95 % CI: 1.04–1.91 for normal weight respondents), though differences between groups were not statistically significant. A threshold analysis for non-accidental mortality estimated a threshold concentration of 0 μg/m3 (+95 % CI = 4.5 μg/m3).
Conclusions
Increased risks of non-accidental, circulatory, and respiratory mortality were observed even at very low concentrations of ambient PM2.5. HRs were generally greater than most literature values, and adjusting for behavioural covariates served to reduce HR estimates slightly.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0111-6) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0111-6
PMCID: PMC4750218  PMID: 26864652
PM2.5; Fine particulate matter; Air pollution; Cardiovascular mortality; Respiratory mortality
Environmental Health  2016;15:17.
Background
Air pollution in Beijing, especially PM2.5, has received increasing attention in the past years. Although exposure to PM2.5 has been linked to many health issues, few studies have quantified the impact of PM2.5 on the risk of influenza-like illness (ILI). The aim of our study is to investigate the association between daily PM2.5 and ILI risk in Beijing, by means of a generalized additive model.
Methods
Daily PM2.5, meteorological factors, and influenza-like illness (ILI) counts during January 1, 2008 to December 31, 2014 were retrieved. An inverse Gaussian generalized additive model with log link function was used to flexibly model the nonlinear relationship between the PM2.5 (single- and multiday lagged exposure) and ILI risk, adjusted for the weather conditions, seasonal and year trends. We also assessed if the effect of PM2.5 differs during flu season versus non-flu season by including the interaction term between PM2.5 and flu season in the model. Furthermore, a stratified analysis by age groups was conducted to investigate how the effect of PM2.5 differs across age groups.
Results
Our findings suggested a strong positive relationships between PM2.5 and ILI risk at the flu season (October-April) (p-value < 0.001), after adjusting for the effects of ambient daily temperature and humidity, month and year; whereas no significant association was identified at the non-flu season (May-September) (p-value = 0.174). A short term delayed effect of PM2.5 was also identified with 2-day moving average (current day to the previous day) of PM2.5 yielding the best predictive power. Furthermore, PM2.5 was strongly associated with ILI risk across all age groups (p-value < 0.001) at the flu season, but the effect was the most pronounced among adults (age 25–59), followed by young adults (age 15–24), school children (age 5–14) and the elderly (age 60+) and the effect of PM2.5 was the least pronounced for children under 5 years of age (age < 5).
Conclusions
Ambient PM2.5 concentrations were significantly associated with ILI risk in Beijing at the flu season and the effect of PM2.5 differed across age groups, in Beijing, China.
doi:10.1186/s12940-016-0115-2
PMCID: PMC4750357  PMID: 26864833
PM2.5; Influenza; Meteorological factor; Spline; Generalized additive model
Environmental Health  2016;15:15.
Background
The current food system generates about 25 % of total greenhouse gas emissions (GHGE), including deforestation, and thereby substantially contributes to the warming of the earth’s surface. To understand the association between food and nutrient intake and GHGE, we therefore need valid methods to assess diet-related GHGE in observational studies.
Methods
Life cycle assessment (LCA) studies assess the environmental impact of different food items. We linked LCA data expressed as kg carbon dioxide equivalents (CO2e) per kg food product to data on food intake assessed by the food frequency questionnaire (FFQ) Meal-Q and validated it against a 7-day weighed food record (WFR). 166 male and female volunteers aged 20–63 years completed Meal-Q and the WFR, and their food intake was linked to LCA data.
Results
The mean GHGE assessed with Meal-Q was 3.76 kg CO2e per day and person, whereas it was 5.04 kg CO2e using the WFR. The energy-adjusted and deattenuated Pearson and Spearman correlation coefficients were 0.68 and 0.70, respectively. Moreover, compared to the WFR, Meal-Q provided a good ranking ability, with 90 % of the participants classified into the same or adjacent quartile according to their daily average CO2e. The Bland-Altman plot showed an acceptable level of agreement between the two methods and the reproducibility of Meal-Q was high.
Conclusions
This is the first study validating the assessment of diet-related GHGE by a questionnaire. The results suggest that Meal-Q is a useful tool for studying the link between food habits and CO2e in future epidemiological studies.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0110-7) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0110-7
PMCID: PMC4748591  PMID: 26860262
Validation studies; Reproducibility of results; Food frequency questionnaire; Weighed food record; Epidemiology; Greenhouse gas emission; Climate change; Life cycle assessment; Carbon dioxide equivalents; Sustainable diets
Environmental Health  2016;15:14.
Background
Epidemiological studies suggest that air pollution is adversely associated with pregnancy outcomes. Such associations may be modified by spatially-varying factors including socio-demographic characteristics, land-use patterns and unaccounted exposures. Yet, few studies have systematically investigated the impact of these factors on spatial variability of the air pollution’s effects. This study aimed to examine spatial variability of the effects of air pollution on term birth weight across Census tracts and the influence of tract-level factors on such variability.
Methods
We obtained over 900,000 birth records from 2001 to 2008 in Los Angeles County, California, USA. Air pollution exposure was modeled at individual level for nitrogen dioxide (NO2) and nitrogen oxides (NOx) using spatiotemporal models. Two-stage Bayesian hierarchical non-linear models were developed to (1) quantify the associations between air pollution exposure and term birth weight within each tract; and (2) examine the socio-demographic, land-use, and exposure-related factors contributing to the between-tract variability of the associations between air pollution and term birth weight.
Results
Higher air pollution exposure was associated with lower term birth weight (average posterior effects: −14.7 (95 % CI: −19.8, −9.7) g per 10 ppb increment in NO2 and −6.9 (95 % CI: −12.9, −0.9) g per 10 ppb increment in NOx). The variation of the association across Census tracts was significantly influenced by the tract-level socio-demographic, exposure-related and land-use factors. Our models captured the complex non-linear relationship between these factors and the associations between air pollution and term birth weight: we observed the thresholds from which the influence of the tract-level factors was markedly exacerbated or attenuated. Exacerbating factors might reflect additional exposure to environmental insults or lower socio-economic status with higher vulnerability, whereas attenuating factors might indicate reduced exposure or higher socioeconomic status with lower vulnerability.
Conclusions
Our Bayesian models effectively combined a priori knowledge with training data to infer the posterior association of air pollution with term birth weight and to evaluate the influence of the tract-level factors on spatial variability of such association. This study contributes new findings about non-linear influences of socio-demographic factors, land-use patterns, and unaccounted exposures on spatial variability of the effects of air pollution.
Electronic supplementary material
The online version of this article (doi:10.1186/s12940-016-0112-5) contains supplementary material, which is available to authorized users.
doi:10.1186/s12940-016-0112-5
PMCID: PMC4744429  PMID: 26850268
Bayesian hierarchical model; Spatial variability; Health effect; Air pollution; Term birth weight

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