A Biomarker Validation Study of Prenatal Chlorpyrifos Exposure within an Inner-City Cohort during Pregnancy

Background

We previously documented significant decreases in chlorpyrifos concentrations in maternal personal and indoor air samples among pregnant African-American and Dominican women from New York City after the 2000–2001 restrictions on its residential use.

Objective

We undertook a biomarker validation study within the same cohort to evaluate trends over time in multiple biomarkers of prenatal chlorpyrifos exposure.

Methods

Subjects were enrolled between February 2001 and May 2004 (n = 102). We measured 3,5,6-trichloro-2-pyridinol (TCPy) in postpartum meconium (n = 83), repeat prenatal maternal spot urine samples (n = 253), and postnatal urine from the mothers (n = 73) and newborns (n = 59). We measured chlorpyrifos in postnatal maternal (n = 92) and umbilical cord (n = 65) blood.

Results

We did not detect TCPy in infant urine, but all other biomarkers showed a highly significant decrease in detection frequencies (χ² = 7.8–34.0, p ≤ 0.005) and mean ranks (p ≤ 0.006, Kruskal–Wallis) among subjects enrolled in 2003–2004 compared with those enrolled in 2001–2002. Chlorpyrifos in maternal personal and indoor air declined 2- to 3-fold over the same period (p < 0.05). In 2001–2002 samples, TCPy levels in repeat prenatal urine were positively correlated (r = 0.23–0.56), but within-subject variability exceeded between-subject variability (intraclass correlation coefficient = 0.43); indoor air levels explained 19% of the variance in prenatal urine TCPy (p = 0.001). Meconium TCPy concentrations were positively correlated with chlorpyrifos in maternal and cord blood (r = 0.25–0.33, p < 0.05) and with TCPy in maternal urine (r = 0.31, p < 0.01).

Conclusions

Results suggest the biomarkers are reliable dosimeters to differentiate between groups with prenatal chlorpyrifos exposures varying by a factor of 2 or more and vividly illustrate the efficacy of residential restriction on chlorpyrifos to reduce the internal dose during pregnancy.     

Are day-to-day variations of airborne particles associated with emergency ambulance dispatches?

Background:

Much of the evidence on the health effects of airborne particles is based on mortality and hospital admissions, while the evidence from other morbidity indicators is still limited.

Objective:

To measure the relationship between particles with diameter below 10 μm (PM₁₀) and emergency ambulance dispatches (EAD).

Methods:

Daily EAD for six towns of the Emilia-Romagna region (Italy) were obtained from a database collecting real-time data. Time series analyses were performed, and city-specific estimates were combined using meta-analytic techniques.

Results:

We found a significant percentage change of EAD associated with a 10 μg/m³ increase of PM₁₀ for non-traumatic diseases (0.86%, 95%CI: 0.61,1.1%). A positive relationship was also found for cardiovascular and respiratory diseases without reaching statistical significance. The risks were much higher in the warm (April–September) than in the cold season (January–March and October–December).

Conclusions:

Emergency ambulance dispatches provide useful insight into the health effects of air pollution and may be useful to establish surveillance systems.     

Potential for Occupational Exposure to Engineered Carbon-Based Nanomaterials in Environmental Laboratory Studies

Background

The potential exists for laboratory personnel to be exposed to engineered carbon-based nanomaterials (CNMs) in studies aimed at producing conditions similar to those found in natural surface waters [e.g., presence of natural organic matter (NOM)].

Objective

The goal of this preliminary investigation was to assess the release of CNMs into the laboratory atmosphere during handling and sonication into environmentally relevant matrices.

Methods

We measured fullerenes (C60), underivatized multiwalled carbon nanotubes (raw MWCNT), hydroxylated MWCNT (MWCNT-OH), and carbon black (CB) in air as the nanomaterials were weighed, transferred to beakers filled with reconstituted freshwater, and sonicated in deionized water and reconstituted freshwater with and without NOM. Airborne nanomaterials emitted during processing were quantified using two hand-held particle counters that measure total particle number concentration per volume of air within the nanometer range (10–1,000 nm) and six specific size ranges (300–10,000 nm). Particle size and morphology were determined by transmission electron microscopy of air sample filters.

Discussion

After correcting for background particle number concentrations, it was evident that increases in airborne particle number concentrations occurred for each nanomaterial except CB during weighing, with airborne particle number concentrations inversely related to particle size. Sonicating nanomaterial-spiked water resulted in increased airborne nanomaterials, most notably for MWCNT-OH in water with NOM and for CB.

Conclusion

Engineered nanomaterials can become airborne when mixed in solution by sonication, especially when nanomaterials are functionalized or in water containing NOM. This finding indicates that laboratory workers may be at increased risk of exposure to engineered nanomaterials.     

Maternal Personal Exposure to Airborne Benzene and Intrauterine Growth

Background

Studies relying on outdoor pollutants measures have reported associations between air pollutants and birth weight.

Objective

Our aim was to assess the relation between maternal personal exposure to airborne benzene during pregnancy and fetal growth.

Methods

We recruited pregnant women in two French maternity hospitals in 2005–2006 as part of the EDEN mother–child cohort. A subsample of 271 nonsmoking women carried a diffusive air sampler for a week during the 27th gestational week, allowing assessment of benzene exposure. We estimated head circumference of the offspring by ultrasound measurements during the second and third trimesters of pregnancy and at birth.

Results

Median benzene exposure was 1.8 μg/m³ (5th, 95th percentiles, 0.5, 7.5 μg/m³). Log-transformed benzene exposure was associated with a gestational age–adjusted decrease of 68 g in mean birth weight [95% confidence interval (CI), −135 to −1 g] and of 1.9 mm in mean head circumference at birth (95% CI, −3.8 to 0.0 mm). It was associated with an adjusted decrease of 1.9 mm in head circumference assessed during the third trimester (95% CI, −4.0 to 0.3 mm) and of 1.5 mm in head circumference assessed at the end of the second trimester of pregnancy (95% CI, −3.1 to 0 mm).

Conclusions

Our prospective study among pregnant women is one of the first to rely on personal monitoring of exposure; a limitation is that exposure was assessed during 1 week only. Maternal benzene exposure was associated with decreases in birth weight and head circumference during pregnancy and at birth. This association could be attributable to benzene and a mixture of associated traffic-related air pollutants.     

What Does a Mathematical Model Tell About the Impact of Reinfection in Korean Tuberculosis Infection?

Objectives

According to the Korea Centers for Disease Control and Prevention, new active tuberculosis (TB) cases have increased since 2001. Some key factors explain and characterize the transmission dynamics of Korean TB infection, such as a higher ratio of latent individuals and a new reporting system implemented in 2001, among others.

Methods

We propose a mathematical TB model that includes exogenous reinfection to gain a better understanding of the recent trend for TB incidence. We divide the simulation time window into two periods, 1970–2000 and 2001–2012, according to the implementation date of a new TB detection system.

Results

Two sets of parameters, including the transmission rate, the latent period, the recovery rate, and the proportion of exogenous reinfection, are estimated using the least-squares method and calibrated to data on the incidence of active TB.

Conclusion

Among some key parameters in the model, the case finding effort turned out to be the most significant impacting component on the reduction in the active TB cases.     

Lung Cancer in Chinese Women: Evidence for an Interaction between Tobacco Smoking and Exposure to Inhalants in the Indoor Environment

Background

Epidemiologic data suggest that Chinese women have a high incidence of lung cancer in relation to their smoking prevalence. In addition to active tobacco smoke exposure, other sources of fumes and airborne particles in the indoor environment, such as cooking and burning of incense and mosquito coils, have been considered potential risk factors for lung cancer.

Objectives

We used a case–control study to explore effects of inhalants from combustion sources common in the domestic environment on lung cancer and their modification by active tobacco smoking.

Methods

We analyzed 703 primary lung cancer cases and 1,578 controls. Data on demographic background and relevant exposures were obtained by face-to-face interviews in the hospital.

Results

We observed a positive relationship with daily exposure to incense or mosquito coils and to cooking fumes only among smokers, and no association among lifetime nonsmokers. Interactions between smoking and frequency of cooking, or exposure to incense or mosquito coils were statistically significant and consistent with synergistic effects on lung cancer. The odds ratio (OR) comparing smokers without daily incense or mosquito coil exposure with nonsmokers without daily exposure was 2.80 [95% confidence interval (CI), 1.86–4.21], whereas the OR comparing smokers with daily exposure to the same referent group was 4.61 (95% CI, 3.41–6.24). In contrast, daily exposure to incense or mosquito coils was not associated with lung cancer among nonsmokers (OR = 0.91; 95% CI, 0.72–1.16). We observed the same pattern of associations for smokers without (OR = 2.31; 95% CI, 1.52–3.51) and with (OR = 4.50; 95% CI, 3.21–6.30) daily cooking exposure compared with nonsmokers, with no evidence of an association with daily cooking exposure among nonsmokers.

Conclusion

Our results suggest that active tobacco smoking not only is an important risk factor for development of lung cancer, but also may cause smokers to be more susceptible to the risk-enhancing effects of other inhalants.     

Space–Time Covariation of Mortality with Temperature: A Systematic Study of Deaths in France, 1968–2009

Background

The temperature–mortality relationship has repeatedly been found, mostly in large cities, to be U/J-shaped, with higher minimum mortality temperature (MMT) at low latitudes being interpreted as indicating human adaptation to climate.

Objectives

Our aim was to partition space with a high-resolution grid to assess the temperature–mortality relationship in a territory with wide climate diversity, over a period with notable climate warming.

Methods

The 16,487,668 death certificates of persons > 65 years of age who died of natural causes in continental France (1968–2009) were analyzed. A 30-km × 30-km grid was placed over the map of France. Generalized additive model regression was used to assess the temperature–mortality relationship for each grid square, and extract the MMT and the RM25 and RM25/18 (respectively, the ratios of mortality at 25°C/MMT and 25°C/18°C). Three periods were considered: 1968–1981 (P1), 1982–1995 (P2), and 1996–2009 (P3).

Results

All temperature–mortality curves computed over the 42-year period were U/J-shaped. MMT and mean summer temperature were strongly correlated. Mean MMT increased from 17.5°C for P1 to 17.8°C for P2 and to 18.2°C for P3 and paralleled the summer temperature increase observed between P1 and P3. The temporal MMT rise was below that expected from the geographic analysis. The RM25/18 ratio of mortality at 25°C versus that at 18°C declined significantly (p = 5 × 10^–5) as warming increased: 18% for P1, 16% for P2, and 15% for P3.

Conclusions

Results of this spatiotemporal analysis indicated some human adaptation to climate change, even in rural areas.

Citation:

Todd N, Valleron AJ. 2015. Space–time covariation of mortality with temperature: a systematic study of deaths in France, 1968–2009. Environ Health Perspect 123:659–664; http://dx.doi.org/10.1289/ehp.1307771     

Lower limb amputation in England: prevalence,regional variation and relationship with revascularisation,deprivation and risk factors. A retrospective review of hospital data

Objective

We describe the prevalence of major lower limb amputation across England and its relationship with revascularisation, patient demography and disease risk factors.

Design

Retrospective cohort study.

Setting

England 1 April 2003 to 31 March 2009.

Participants

Patients aged 50–84 years.

Main outcome measures

Age standardised prevalence rates were calculated using Hospital Episode Statistics as the numerator with census data as the denominator. The outcome measure ‘amputation with revascularisation’ was created if an amputation could be linked with a revascularisation. Logistic regression determined the odds of having an amputation with a revascularisation across England. Regression was performed unadjusted and repeated after controlling for demographic (age, sex, social deprivation) and disease risk factors (diabetes, hypertension, coronary heart disease, cerebrovascular disease, smoking).

Results

There were 25,312 amputations and 136,215 revascularisations, and 7543 cases were linked. The prevalence rate per 100,000 (95% confidence intervals) for amputation was 26.3 (26.0–26.6) with rates significantly higher in Northern England (North: 31.7; 31.0–32.3, Midlands: 26.0; 25.3–26.7, South: 23.1; 22.6–23.5). The revascularisation rate was 141.6 (140.8–142.3) with significantly higher rates again in Northern England (North: 182.1; 180.5–183.7, Midlands: 121.3; 119.8–122.9, South 124.9; 123.9–125.8). The odds of having an amputation with a revascularisation remained significantly higher in the North (OR 1.22; 1.13–1.33) even after controlling demographic and disease risk factors.

Conclusions

There is a North–South divide in England for both major lower limb amputation and revascularisation. The higher odds of having an amputation with a revascularisation in the North were not fully explained by greater levels of deprivation or disease risk factors.     

A Unified Probabilistic Framework for Dose–Response Assessment of Human Health Effects

Background

When chemical health hazards have been identified, probabilistic dose–response assessment (“hazard characterization”) quantifies uncertainty and/or variability in toxicity as a function of human exposure. Existing probabilistic approaches differ for different types of endpoints or modes-of-action, lacking a unifying framework.

Objectives

We developed a unified framework for probabilistic dose–response assessment.

Methods

We established a framework based on four principles: a) individual and population dose responses are distinct; b) dose–response relationships for all (including quantal) endpoints can be recast as relating to an underlying continuous measure of response at the individual level; c) for effects relevant to humans, “effect metrics” can be specified to define “toxicologically equivalent” sizes for this underlying individual response; and d) dose–response assessment requires making adjustments and accounting for uncertainty and variability. We then derived a step-by-step probabilistic approach for dose–response assessment of animal toxicology data similar to how nonprobabilistic reference doses are derived, illustrating the approach with example non-cancer and cancer datasets.

Results

Probabilistically derived exposure limits are based on estimating a “target human dose” (HD_M^I), which requires risk management–informed choices for the magnitude (M) of individual effect being protected against, the remaining incidence (I) of individuals with effects ≥ M in the population, and the percent confidence. In the example datasets, probabilistically derived 90% confidence intervals for HD_M^I values span a 40- to 60-fold range, where I = 1% of the population experiences ≥ M = 1%–10% effect sizes.

Conclusions

Although some implementation challenges remain, this unified probabilistic framework can provide substantially more complete and transparent characterization of chemical hazards and support better-informed risk management decisions.

Citation

Chiu WA, Slob W. 2015. A unified probabilistic framework for dose–response assessment of human health effects. Environ Health Perspect 123:1241–1254; http://dx.doi.org/10.1289/ehp.1409385     

Climate Variability and Hemorrhagic Fever with Renal Syndrome Transmission in Northeastern China

Background

The transmission of hemorrhagic fever with renal syndrome (HFRS) is influenced by climatic variables. However, few studies have examined the quantitative relationship between climate variation and HFRS transmission.

Objective

We examined the potential impact of climate variability on HFRS transmission and developed climate-based forecasting models for HFRS in northeastern China.

Methods

We obtained data on monthly counts of reported HFRS cases in Elunchun and Molidawahaner counties for 1997–2007 from the Inner Mongolia Center for Disease Control and Prevention and climate data from the Chinese Bureau of Meteorology. Cross-correlations assessed crude associations between climate variables, including rainfall, land surface temperature (LST), relative humidity (RH), and the multivariate El Niño Southern Oscillation (ENSO) index (MEI) and monthly HFRS cases over a range of lags. We used time-series Poisson regression models to examine the independent contribution of climatic variables to HFRS transmission.

Results

Cross-correlation analyses showed that rainfall, LST, RH, and MEI were significantly associated with monthly HFRS cases with lags of 3–5 months in both study areas. The results of Poisson regression indicated that after controlling for the autocorrelation, seasonality, and long-term trend, rainfall, LST, RH, and MEI with lags of 3–5 months were associated with HFRS in both study areas. The final model had good accuracy in forecasting the occurrence of HFRS.

Conclusions

Climate variability plays a significant role in HFRS transmission in northeastern China. The model developed in this study has implications for HFRS control and prevention.     

Cord Blood Methylmercury and Fetal Growth Outcomes in Baltimore Newborns: Potential Confounding and Effect Modification by Omega-3 Fatty Acids,Selenium, and Sex

Background

Methylmercury (MeHg) may affect fetal growth; however, prior research often lacked assessment of mercury speciation, confounders, and interactions.

Objective

Our objective was to assess the relationship between MeHg and fetal growth as well as the potential for confounding or interaction of this relationship from speciated mercury, fatty acids, selenium, and sex.

Methods

This cross-sectional study includes 271 singletons born in Baltimore, Maryland, 2004–2005. Umbilical cord blood was analyzed for speciated mercury, serum omega-3 highly unsaturated fatty acids (n-3 HUFAs), and selenium. Multivariable linear regression models controlled for gestational age, birth weight, maternal age, parity, prepregnancy body mass index, smoking, hypertension, diabetes, selenium, n-3 HUFAs, and inorganic mercury (IHg).

Results

Geometric mean cord blood MeHg was 0.94 μg/L (95% CI: 0.84, 1.07). In adjusted models for ponderal index, βln(MeHg) = –0.045 (g/cm³) × 100 (95% CI: –0.084, –0.005). There was no evidence of a MeHg × sex interaction with ponderal index. Contrastingly, there was evidence of a MeHg × n-3 HUFAs interaction with birth length [among low n-3 HUFAs, βln(MeHg) = 0.40 cm, 95% CI: –0.02, 0.81; among high n-3 HUFAs, βln(MeHg) = –0.15, 95% CI: –0.54, 0.25; p-interaction = 0.048] and head circumference [among low n-3 HUFAs, βln(MeHg) = 0.01 cm, 95% CI: –0.27, 0.29; among high n-3 HUFAs, βln(MeHg) = –0.37, 95% CI: –0.63, –0.10; p-interaction = 0.042]. The association of MeHg with birth weight and ponderal index was affected by n-3 HUFAs, selenium, and IHg. For birth weight, βln(MeHg) without these variables was –16.8 g (95% CI: –75.0, 41.3) versus –29.7 (95% CI: –93.9, 34.6) with all covariates. Corresponding values for ponderal index were –0.030 (g/cm³) × 100 (95% CI: –0.065, 0.005) and –0.045 (95% CI: –0.084, –0005).

Conclusion

We observed an association of increased MeHg with decreased ponderal index. There is evidence for interaction between MeHg and n-3 HUFAs; infants with higher MeHg and n-3 HUFAs had lower birth length and head circumference. These results should be verified with additional studies.

Citation

Wells EM, Herbstman JB, Lin YH, Jarrett J, Verdon CP, Ward C, Caldwell KL, Hibbeln JR, Witter FR, Halden RU, Goldman LR. 2016. Cord blood methylmercury and fetal growth outcomes in Baltimore newborns: potential confounding and effect modification by omega-3 fatty acids, selenium, and sex. Environ Health Perspect 124:373–379; http://dx.doi.org/10.1289/ehp.1408596     

Prenatal Exposure to Airborne Polycyclic Aromatic Hydrocarbons and Children’s Intelligence at 5 Years of Age in a Prospective Cohort Study in Poland

Background

In this prospective cohort study of Caucasian mothers and children in Krakow, Poland, we evaluated the role of prenatal exposure to urban air pollutants in the pathogenesis of neurobehavioral disorders.

Objectives

The objective of this study was to investigate the relationship between prenatal polycyclic aromatic hydrocarbon (PAH) exposure and child intelligence at 5 years of age, controlling for potential confounders suspected to play a role in neurodevelopment.

Methods

A cohort of pregnant, healthy, nonsmoking women was enrolled in Krakow, Poland, between 2001 and 2006. During pregnancy, participants were invited to complete a questionnaire and undergo 48-hr personal air monitoring to estimate their babies’ exposure, and to provide a blood sample and/or a cord blood sample at the time of delivery. Two hundred fourteen children were followed through 5 years of age, when their nonverbal reasoning ability was assessed using the Raven Coloured Progressive Matrices (RCPM).

Results

We found that higher (above the median of 17.96 ng/m³) prenatal exposure to airborne PAHs (range, 1.8–272.2 ng/m³) was associated with decreased RCPM scores at 5 years of age, after adjusting for potential confounding variables (n = 214). Further adjusting for maternal intelligence, lead, or dietary PAHs did not alter this association. The reduction in RCPM score associated with high airborne PAH exposure corresponded to an estimated average decrease of 3.8 IQ points.

Conclusions

These results suggest that prenatal exposure to airborne PAHs adversely affects children’s cognitive development by 5 years of age, with potential implications for school performance. They are consistent with a recent finding in a parallel cohort in New York City.     

Risk of self-harm and suicide in people with specific psychiatric and physical disorders: comparisons between disorders using English national record linkage

Background

Psychiatric illnesses are known risk factors for self-harm but associations between self-harm and physical illnesses are less well established. We aimed to stratify selected chronic physical and psychiatric illnesses according to their relative risk of self-harm.

Design

Retrospective cohort studies using a linked dataset of Hospital Episode Statistics (HES) for 1999–2011.

Participants

Individuals with selected psychiatric or physical conditions were compared with a reference cohort constructed from patients admitted for a variety of other conditions and procedures.

Setting

All admissions and day cases in National Health Service (NHS) hospitals in England.

Main outcome measures

Hospital episodes of self-harm. Rate ratios (RRs) were derived by comparing admission for self-harm between cohorts.

Results

The psychiatric illnesses studied (depression, bipolar disorder, alcohol abuse, anxiety disorders, eating disorders, schizophrenia and substance abuse) all had very high RRs (> 5) for self-harm. Of the physical illnesses studied, an increased risk of self-harm was associated with epilepsy (RR = 2.9, 95% confidence interval [CI] 2.8–2.9), asthma (1.8, 1.8–1.9), migraine (1.8, 1.7–1.8), psoriasis (1.6, 1.5–1.7), diabetes mellitus (1.6, 1.5–1.6), eczema (1.4, 1.3–1.5) and inflammatory polyarthropathies (1.4, 1.3–1.4). RRs were significantly low for cancers (0.95, 0.93–0.97), congenital heart disease (0.9, 0.8–0.9), ulcerative colitis (0.8, 0.7–0.8), sickle cell anaemia (0.7, 0.6–0.8) and Down''s syndrome (0.1, 0.1–0.2).

Conclusions

Psychiatric illnesses carry a greatly increased risk of self-harm as well as of suicide. Many chronic physical illnesses are also associated with an increased risk of both self-harm and suicide. Identifying those at risk will allow provision of appropriate monitoring and support.     

Use of seasonal influenza virus titer and respiratory symptom score to estimate effective human contact rates

Background

We linked viral titers and respiratory symptom scores for seasonal influenza to estimate the effective contact rate among schoolchildren.

Methods

We analyzed 274 diary-based questionnaires. In addition, 2 sets of influenza data from published studies were used to investigate the relationship between viral titer, total symptom score, and normalized contact rate in children.

Results

The mean number (SD) of contacts for children in grades 7 to 9 ranged from 9.44 ± 8.68 to 11.18 ± 7.98 person⁻¹ day⁻¹; contact behavior was similar across school grades. The mean number of contacts was 5.66 ± 6.23 person⁻¹ day⁻¹ (range, 0 to 44 person⁻¹ day⁻¹) for the age group of 13 to 19 years. Estimated contact age, household size, contact duration, and contact frequency were the variables most strongly associated with total number of contacts. We also found that a reduction in total respiratory symptom scores among infected individuals had a positive correlation with an increase in the normalized contact rate.

Conclusions

The relationship between daily virus titer and respiratory symptom score can be used to estimate the effective contact rate in explaining the spread of an airborne transmissible disease. The present findings can be incorporated into population-dynamic models of influenza transmission among schoolchildren.Key words: influenza, behavior, contact rate, symptom score, modeling     

Chemosensory Loss: Functional Consequences of the World Trade Center Disaster

Background

Individuals involved in rescue, recovery, demolition, and cleanup at the World Trade Center (WTC) site were exposed to a complex mixture of airborne smoke, dust, combustion gases, acid mists, and metal fumes. Such exposures have the potential to impair nasal chemosensory (olfactory and trigeminal) function.

Objective

The goal of this study was to evaluate the prevalence of chemosensory dysfunction and nasal inflammation among these individuals.

Methods

We studied 102 individuals who worked or volunteered at the WTC site in the days and weeks during and after 11 September 2001 (9/11) and a comparison group with no WTC exposure matched to each participant on age, sex, and job title. Participants were comprehensively evaluated for chemosensory function and nasal inflammation in a single session. Individual exposure history was obtained from self-reported questionnaires.

Results

The prevalence of olfactory and trigeminal nerve sensitivity loss was significantly greater in the WTC-exposed group relative to the comparison group [prevalence ratios (95% confidence intervals) = 1.96 (1.2–3.3) and 3.28 (2.7–3.9) for odor and irritation thresholds, respectively]. Among the WTC responders, however, individuals caught in the dust cloud from the collapse on 9/11 exhibited the most profound trigeminal loss. Analysis of the nasal lavage samples supported the clinical findings of chronic nasal inflammation among the WTC-exposed cohort.

Conclusions

The prevalence of significant chemosensory impairment in the WTC-exposed group more than 2 years after their exposure raises concerns for these individuals when the ability to detect airborne odors or irritants is a critical safety factor.

Relevance to clinical practice

This outcome highlights the need for chemosensory evaluations among individuals with exposure to acute high or chronic levels of airborne pollutants.     

Persistent Organic Pollutants Modify Gut Microbiota–Host Metabolic Homeostasis in Mice Through Aryl Hydrocarbon Receptor Activation

Background

Alteration of the gut microbiota through diet and environmental contaminants may disturb physiological homeostasis, leading to various diseases including obesity and type 2 diabetes. Because most exposure to environmentally persistent organic pollutants (POPs) occurs through the diet, the host gastrointestinal tract and commensal gut microbiota are likely to be exposed to POPs.

Objectives

We examined the effect of 2,3,7,8-tetrachlorodibenzofuran (TCDF), a persistent environmental contaminant, on gut microbiota and host metabolism, and we examined correlations between gut microbiota composition and signaling pathways.

Methods

Six-week-old male wild-type and Ahr^–/– mice on the C57BL/6J background were treated with 24 μg/kg TCDF in the diet for 5 days. We used 16S rRNA gene sequencing, ¹H nuclear magnetic resonance (NMR) metabolomics, targeted ultra-performance liquid chromatography coupled with triplequadrupole mass spectrometry, and biochemical assays to determine the microbiota compositions and the physiological and metabolic effects of TCDF.

Results

Dietary TCDF altered the gut microbiota by shifting the ratio of Firmicutes to Bacteroidetes. TCDF-treated mouse cecal contents were enriched with Butyrivibrio spp. but depleted in Oscillobacter spp. compared with vehicle-treated mice. These changes in the gut microbiota were associated with altered bile acid metabolism. Further, dietary TCDF inhibited the farnesoid X receptor (FXR) signaling pathway, triggered significant inflammation and host metabolic disorders as a result of activation of bacterial fermentation, and altered hepatic lipogenesis, gluconeogenesis, and glycogenolysis in an AHR-dependent manner.

Conclusion

These findings provide new insights into the biochemical consequences of TCDF exposure involving the alteration of the gut microbiota, modulation of nuclear receptor signaling, and disruption of host metabolism.

Citation

Zhang L, Nichols RG, Correll J, Murray IA, Tanaka N, Smith PB, Hubbard TD, Sebastian A, Albert I, Hatzakis E, Gonzalez FJ, Perdew GH, Patterson AD. 2015. Persistent organic pollutants modify gut microbiota–host metabolic homeostasis in mice through aryl hydrocarbon receptor activation. Environ Health Perspect 123:679–688; http://dx.doi.org/10.1289/ehp.1409055     

Airborne Endotoxin Concentrations in Homes Burning Biomass Fuel

Background

About half of the world’s population is exposed to smoke from burning biomass fuels at home. The high airborne particulate levels in these homes and the health burden of exposure to this smoke are well described. Burning unprocessed biological material such as wood and dried animal dung may also produce high indoor endotoxin concentrations.

Objective

In this study we measured airborne endotoxin levels in homes burning different biomass fuels.

Methods

Air sampling was carried out in homes burning wood or dried animal dung in Nepal (n = 31) and wood, charcoal, or crop residues in Malawi (n = 38). Filters were analyzed for endotoxin content expressed as airborne endotoxin concentration and endotoxin per mass of airborne particulate.

Results

Airborne endotoxin concentrations were high. Averaged over 24 hr in Malawian homes, median concentrations of total inhalable endotoxin were 24 endotoxin units (EU)/m³ in charcoal-burning homes and 40 EU/m³ in wood-burning homes. Short cooking-time samples collected in Nepal produced median values of 43 EU/m³ in wood-burning homes and 365 EU/m³ in dung-burning homes, suggesting increasing endotoxin levels with decreasing energy levels in unprocessed solid fuels.

Conclusions

Airborne endotoxin concentrations in homes burning biomass fuels are orders of magnitude higher than those found in homes in developed countries where endotoxin exposure has been linked to respiratory illness in children. There is a need for work to identify the determinants of these high concentrations, interventions to reduce exposure, and health studies to examine the effects of these sustained, near-occupational levels of exposure experienced from early life.     

Traffic-Related Air Pollution and Parkinson’s Disease in Denmark: A Case–Control Study

Background

Very little is currently known about air pollutants’ adverse effects on neurodegenerative diseases even though recent studies have linked particulate exposures to brain pathologies associated with Parkinson’s and Alzheimer’s disease.

Objective

In the present study, we investigated long-term exposure to traffic-related air pollution and Parkinson’s disease.

Methods

In a case–control study of 1,696 Parkinson’s disease (PD) patients identified from Danish hospital registries and diagnosed 1996–2009 and 1,800 population controls matched by sex and year of birth, we assessed long-term traffic-related air pollutant exposures (represented by nitrogen dioxide; NO₂) from a dispersion model, using residential addresses from 1971 to the date of diagnosis or first cardinal symptom for cases and the corresponding index date for their matched controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated with logistic regression, adjusting for matching factors and potential confounders.

Results

We found ambient air pollution from traffic sources to be associated with risk of PD, with a 9% higher risk (95% CI: 3, 16.0%) per interquartile range increase (2.97 μg/m³) in modeled NO₂. For participants living for ≥ 20 years in the capital city, ORs were larger (OR = 1.21; 95% CI: 1.11, 1.31) than in provincial towns (OR = 1.10; 95% CI: 0.97, 1.26), whereas there was no association among rural residents.

Conclusions

Our findings raise concerns about potential effects of air pollution from traffic and other sources on the risk of PD, particularly in populations with high or increasing exposures.

Citation

Ritz B, Lee PC, Hansen J, Funch Lassen C, Ketzel M, Sørensen M, Raaschou-Nielsen O. 2016. Traffic-related air pollution and Parkinson’s disease in Denmark: a case–control study. Environ Health Perspect 124:351–356; http://dx.doi.org/10.1289/ehp.1409313     

Hormonal contraceptives and asthma in women of reproductive age: analysis of data from serial national Scottish Health Surveys

Objectives

Sex steroid hormones may explain known gender-related variations in asthma prevalence and clinical manifestation. We investigated the relationship between use of hormonal contraceptives and asthma in women, and assessed evidence of biological interaction between use of hormonal contraceptives and body mass index in this relationship.

Design

Population-based analysis using data from serial (i.e. 2003, 2008 and 2010) Scottish Health Surveys.

Setting

Random samples of the Scottish general population.

Participants

A total of 3257 non-pregnant, 16–45-year-old women.

Exposure

Current use of hormonal contraceptives.

Main outcome measures

Self-reported current physician-diagnosed asthma, current wheezing symptoms, wheezing attacks and treatment for asthma or wheeze.

Results

Women comprising 30.9% (95% confidence interval 29.3–32.5) were currently using any hormonal contraceptive and current physician-diagnosed asthma was present in 6.5% (95% confidence interval 5.7–7.4). Use of any hormonal contraceptive was associated with reduced risk of current physician-diagnosed asthma (odds ratio 0.68; 95% confidence interval 0.47–0.98) and receiving ≥3 asthma care episodes (odds ratio 0.45; 95% confidence interval 0.25–0.82), but the evidence was equivocal for wheezing attacks. Use of hormonal contraceptives among overweight or obese women was non-statistically significantly associated with asthma, but there was 42–135% increased risk in overweight and obese non-contraceptive using women.

Conclusions

Use of hormonal contraceptives may reduce asthma exacerbations and number of care episodes. Overweight and obese non-contraceptive-using women may be at increased risk of asthma. Prospective studies are now needed to confirm these findings. Both oestrogen and progesterone may stimulate smooth airway muscle function and inhibit the activities of TH2 responses. Future studies should investigate these underlying mechanisms.     

Nutritional status of HIV-infected women with tuberculosis in Dar es Salaam,Tanzania

Setting:

Tuberculosis (TB) treatment clinics in Dar es Salaam, Tanzania.

Objective:

To quantify anthropometrics and intake of en-ergy and protein among human immunodeficiency virus (HIV) positive women with TB.

Design:

HIV-positive women with newly diagnosed TB were assessed on their anthropometric characteristics and dietary intake. Energy and protein intake were determined using Tanzania food composition tables and compared with standard recommendations. Patients were re-evaluated after 4–6 months of anti-tuberculosis treatment.

Results:

Among 43 women, the baseline median CD4 count was 209 cells/µl (range 8–721); 19 (44%) had a CD4 count of <200; 20 (47%) were on antiretroviral therapy. Body mass index was <18.5 kg/m² in 25 (58%); the median food insecurity score was 6. The median level of kcal/day was 1693 (range 1290–2633) compared to an estimated need of 2658; the median deficit was 875 kcal (range −65–1278). The median level of protein/day was 42 g (range 27–67) compared to 77 g estimated need; the median protein deficit was 35 g (range 10–50). The median weight gain among 29 patients after 4–6 months was 6 kg.

Conclusion:

HIV-positive women with TB have substantial 24-h deficits in energy and protein intake, report significant food insecurity and gain minimal weight on anti-tuberculosis treatment. Enhanced dietary education together with daily supplementation of 1000 kcal with 40 g protein may be required.