Metabolomic landscape of overall and common cancers in the UK Biobank: A prospective cohort study.

Information about the NMR metabolomics landscape of overall, and common cancers is still limited. Based on a cohort of 83,290 participants from the UK Biobank, we used multivariate Cox regression to assess the associations between each of the 168 metabolites with the risks of overall cancer and 20 specific types of cancer. Then, we applied LASSO to identify important metabolites for overall cancer risk and obtained their associations using multivariate cox regression. We further conducted mediation analysis to evaluate the mediated role of metabolites in the effects of traditional factors on overall cancer risk. Finally, we included the 13 identified metabolites as predictors in prediction models, and compared the accuracies of our traditional models. We found that there were commonalities among the metabolic profiles of overall and specific types of cancer: the top 20 frequently identified metabolites for 20 specific types of cancer were all associated with overall cancer; most of the specific types of cancer had common identified metabolites. Meanwhile, the associations between the same metabolite with different types of cancer can vary based on the site of origin. We identified 13 metabolic biomarkers associated with overall cancer, and found that they mediated the effects of traditional factors. The accuracies of prediction models improved when we added 13 identified metabolites in models. This study is helpful to understand the metabolic mechanisms of overall and a wide range of cancers, and our results also indicate that NMR metabolites are potential biomarkers in cancer diagnosis and prevention.

Associations between home environmental factors and childhood eczema and related symptoms in different cities in China.

Previous studies have shown significant associations between home environmental factors and childhood eczema. However, few studies have compared how associations differ in different regions. This study investigated associations between home environmental factors and childhood eczema ever, and related symptoms including itchy rash (IR) and being awakened by itchy rash at night (awake by IR) in 4 cities located in different regions of China, based on cross-sectional investigations during 2010-2012. We used two-step analysis to explore the associations between influencing factors and eczema/related symptoms: first, group Least Absolute Shrinkage and Selection Operator (LASSO) was conducted to identify important factors among a list of candidates; then, the associations in total study population and in each city were estimated using logistic regression. We found these home environmental factors to be risk factors for eczema or related symptoms: large residence size, shared room, air cleaner at home, abnormal smell, perceived dry air, visible mold or damp stains, cooking with coal or wood, painted wall, incense, mice, new furniture during pregnancy, abnormal smell at birth, window condensation at birth and environmental tobacco smoke at birth. Environmental protective factors were rural house location and window ventilation. Associations of factors with eczema/related symptoms differed across cities. For example, air conditioning was protective for eczema in Beijing and awakening by IR in Shanghai with ORs of 0.70 (95%CI: 0.52, 0.95) and 0.33 (95%CI: 0.14, 0.81) respectively, but not significant in other cities. Our results have implications for improving home environments to reduce the risk of childhood eczema/related symptoms in different regions of China.

A rapid and robust method to determine the key parameters of formaldehyde emissions from building and vehicle cabin materials: Principle, multi-source application and exposure assessment.

The ubiquity of formaldehyde emitted in indoor and in-cabin environments can adversely affect health. This study proposes a novel full-range C-history method to rapidly, accurately and simultaneously determine the three key parameters (initial emittable concentration, partition coefficient, diffusion coefficient) that characterize the emission behaviors of formaldehyde from indoor building and vehicle cabin materials, by means of hybrid optimization. The key parameters of formaldehyde emissions from six building materials and five vehicle cabin materials at various temperatures, were determined. Independent experiments and sensitivity analysis verify the effectiveness and robustness of the method. We also demonstrate that the determined key parameters can be used for predicting multi-source emissions from different material combinations that are widely encountered in realistic indoor and in-cabin environments. Furthermore, based on a constructed vehicle cabin and the determined key parameters, we make a first attempt to estimate the human carcinogenic potential (HCP) of formaldehyde for taxi drivers and passengers at two temperatures (25 °C, 34 °C). The HCP for taxi drivers at both temperatures exceeds 10-6 cases, indicating relatively high potential risk. This study should be helpful for pre-evaluation of indoor and in-cabin air quality, and can assist designers in selecting appropriate materials to achieve effective source control.

Residential building materials: An important source of ambient formaldehyde in mainland China.

This study investigates the contribution of formaldehyde from residential building materials to ambient air in mainland China. Based on 265 indoor field tests in 9 provinces, we estimate that indoor residential sources are responsible for 6.66% of the total anthropogenic formaldehyde in China's ambient air (range for 31 provinces: 1.88-18.79%). Residential building materials rank 6th among 81 anthropogenic sources (range: 2nd-10th for 31 provinces). Emission intensities show large spatial variability between and within regions due to different residential densities, emission characteristics of building materials, and indoor thermal conditions. Our findings indicate that formaldehyde from the indoor environment is a significant source of ambient formaldehyde, especially in urban areas. This study will help to more accurately evaluate exposure to ambient formaldehyde and its related pollutants, and will assist in formulating policies to protect air quality and public health.

Effects of particulate matter gamma radiation on oxidative stress biomarkers in COPD patients.

Inhalation of particulate matter (PM) radioactivity is an important pathway of ionizing radiation exposure. We investigated the associations between short-term exposures to PM gamma radioactivity with oxidative stress in COPD patients. Urinary concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) of 81 COPD patients from Eastern Massachusetts were measured 1-4 times during 2012-2014. Daily ambient and indoor PM gamma activities (gamma-3 through gamma-9) were calculated based on EPA RadNet data and indoor-outdoor infiltration ratios. Linear mixed-effects models were used to examine the associations between biomarkers with PM gamma activities for moving averages from urine collection day to 7 days before. Our results indicate that ambient and indoor PM gamma activities were positively associated with 8-OHdG, with stronger effects for exposure windows closer to urine collection day. For per interquartile range increase in indoor PM gamma activities averaged over urine collection day and 1 day before, 8-OHdG increased from 3.41% (95% CI: -0.88, 7.88) to 8.87% (95% CI: 2.98, 15.1), adjusted for indoor black carbon. For MDA, the timing of greatest effects across the exposure week varied but was nearly all positive. These findings provide insight into the toxigenic properties associated with PM radioactivity and suggest that these exposures promote systemic oxidative stress.

Short-term exposures to particulate matter gamma radiation activities and biomarkers of systemic inflammation and endothelial activation in COPD patients.

BACKGROUND: We hypothesized that particulate matter (PM) gamma activity (gamma radiation associated with PM) is associated with systemic effects. OBJECTIVE: Examine short-term relationships between ambient and indoor exposures to PM gamma activities with systemic inflammation and endothelial activation in chronic obstructive pulmonary disease (COPD) patients. METHODS: In 85 COPD patients from Eastern Massachusetts, USA from 2012 to 2014, plasma C-reactive protein (CRP), interleukin-6 (IL-6), and soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured seasonally up to four times. We used US EPA RadNet data measuring ambient gamma radiation attached to PM adjusted for background radiation, and estimated in-home gamma radiation exposures using the ratio of in-home-to-ambient sulfur in PM2.5. Linear mixed-effects regression models were used to determine associations between moving averages of PM gamma activities through the week before phlebotomy with these biomarkers. We explored ambient and indoor PM2.5, black carbon (BC), and NO2 as confounders. RESULTS: Ambient and indoor PM gamma activities measured as energy spectra classes 3 through 9 were positively associated with CRP and IL-6. For example, averaged from phlebotomy day through previous 6 days, each IQR increase in indoor PM gamma activity for each spectra class, was associated with an CRP increase ranging from 7.45% (95%CI: 2.77, 12.4) to 13.4% (95%CI: 5.82, 21.4) and for ambient exposures were associated with an increase of 8.75% (95%CI: -0.57, 18.95) to 14.8% (95%CI: 4.5, 26.0). Indoor exposures were associated with IL-6 increase of 3.56% (95%CI: 0.31, 6.91) to 6.46% (95%CI:1.33, 11.85) and ambient exposures were associated with an increase of 0.03% (95%CI: -6.37, 6.87) to 3.50% (95%CI: -3.15, 10.61). There were no positive associations with sVCAM-1. Sensitivity analyses using two-pollutant models showed similar effects. CONCLUSIONS: Our results demonstrate that short-term exposures to environmental PM gamma radiation activities were associated with systemic inflammation in COPD patients.

Home environmental and lifestyle factors associated with asthma, rhinitis and wheeze in children in Beijing, China.

BACKGROUND: The prevalence of asthma and allergic diseases has increased rapidly in urban China since 2000. There has been limited study of associations between home environmental and lifestyle factors with asthma and symptoms of allergic disease in China. METHODS: In a cross-sectional analysis of 2214 children in Beijing, we applied a two-step hybrid Least Absolute Shrinkage and Selection Operator (LASSO) algorithm to identify environmental and lifestyle-related factors associated with asthma, rhinitis and wheeze from a wide range of candidates. We used group LASSO to select variables, using cross-validation as the criterion. Effect estimates were then calculated using adaptive LASSO. Model performance was assessed using Area Under the Curve (AUC) values. RESULTS: We found a number of environmental and lifestyle-related factors significantly associated with asthma, rhinitis or wheeze, which changed the probability of asthma, rhinitis or wheeze from -5.76% (95%CI: -7.74%, -3.79%) to 27.4% (95%CI: 16.6%, 38.3%). The three factors associated with the largest change in probability of asthma were short birth length, carpeted floor and paternal allergy; for rhinitis they were maternal smoking during pregnancy, paternal allergy and living close to industrial area; and for wheeze they were carpeted floor, short birth length and maternal allergy. Other home environmental risk factors identified were living close to a highway, industrial area or river, sharing bedroom, cooking with gas, furry pets, cockroaches, incense, printer/photocopier, TV, damp, and window condensation in winter. Lifestyle-related risk factors were child caretakers other than parents, and age<3 for the day-care. Other risk factors included use of antibiotics, and mother's occupation. Major protective factors for wheeze were living in a rural/suburban region, air conditioner use, and mother's occupation in healthcare. CONCLUSIONS: Our findings suggest that changes in lifestyle and indoor environments associated with the urbanization and industrialization of China are associated with asthma, rhinitis, and wheeze in children.

Short-term effects of particle gamma radiation activities on pulmonary function in COPD patients.

BACKGROUND: It is not known whether environmental gamma radiation measured in US cities has detectable adverse health effects. We assessed whether short-term exposure to gamma radiation emitted from ambient air particles [gamma particle activity (PRγ)] is associated with reduced pulmonary function in chronic obstructive pulmonary disease (COPD) patients. OBJECTIVE: We hypothesize that the inhalation of gamma radiation emitted from ambient air particles may be associated with reduced pulmonary function in individuals with COPD. METHODS: In 125 patients with COPD from Eastern Massachusetts who had up to 4 seasonal one-week assessments of particulate matter ≤2.5 µm (PM2.5), black carbon (BC), and sulfur followed by spirometry. The US EPA continuously monitors ambient gamma (γ) radiation including γ released from radionuclides attached to particulate matter that is recorded as 9 γ-energy spectra classes (i = 3-9) in counts per minute (CPMγ) in the Boston area (USA). We analyzed the associations between ambient and indoor PRγi (up to one week) and pre and post-bronchodilator (BD) forced expiratory volume in 1 s (FEV1) and with forced vital capacity (FVC) using mixed-effects regression models. We estimated indoor PRγi using the ratio of the indoor-to-outdoor sulfur in PM2.5 as a proxy for infiltration of ambient radionuclide-associated particles. RESULTS: Overall, exposures to ambient and indoor PRγi were associated with a similar decrease in pre- and post-BD FEV1 and FVC. For example, ambient PRγ3 exposure averaged from the day of pulmonary function testing through the previous 3 days [IQR of 55.1 counts per minute (CPMγ)] was associated with a decrease in pre-BD FEV1 of 21.0 ml (95%CI: -38.5 to -3.0 ml; p < 0.01) and pre-BD FVC of 27.5 ml [95% confidence interval (CI): -50.7 to -5.0 ml; p < 0.01] with similar effects adjusting for indoor and outdoor BC and PM2.5. CONCLUSION: Our results show that short-term ambient and indoor exposures to environmental gamma radiation associated with particulate matter are associated with reduced pre- and post-BD pulmonary function in patients with COPD.

Indoor formaldehyde concentrations in urban China: Preliminary study of some important influencing factors.

The Huai River and Qingling Mountain divide (H-Q) divide China into north and south with respect to public policies for building construction and operation practises. China's building energy efficiency standard mandates that air exchange rates be 0.5h-1 north of the H-Q divide and 1h-1 south of the divide. China's heating policy allows space heating systems only north of the H-Q divide. Consequently, indoor temperature and humidity differ considerably between north and south. A theoretical model using indoor temperature, humidity, and air change rate was developed to predict indoor formaldehyde concentrations. Data for 39 cities were obtained from 42 studies. There was good agreement between the literature and modelling in a theoretical reference room. The United States Environmental Protection Agency (U.S.EPA) model was applied to estimate cancer risk from formaldehyde exposure indoors. The median indoor formaldehyde concentration for renovation ever from 2002 to 2015 in Chinese cities was 125µg/m3, which is higher than the WHO threshold, 100µg/m3. The median indoor formaldehyde concentrations in the north were higher than in the south (0.5 times higher for dwellings renovated within the past year and 0.2 times higher for renovation ever), driven by the much higher northern winter concentrations (40-1320%). The U.S.EPA model predicts that the lifetime formaldehyde related cancer risk for people living north of the H-Q divide is 1.2 times greater than for people living south. This can be partly explained by greater indoor exposure to formaldehyde for Chinese living north of the H-Q divide.

Comprehensive influence of environmental factors on the emission rate of formaldehyde and VOCs in building materials: Correlation development and exposure assessment.

Temperature and relative humidity can simultaneously change in indoor environment, which significantly affect the emission rate of formaldehyde and volatile organic compounds (VOCs) from building materials. Prior studies generally focus on the single effect of temperature or relative humidity, and the combined effect is not considered. This paper investigates the comprehensive influence of temperature and relative humidity on the emission rate of pollutants from building materials. Correlation between the emission rate and the combined environmental factors is derived theoretically. Data in literature are applied to validate the effectiveness of the correlation. With the correlation, the indoor formaldehyde concentration in summer is predicted to be 1.63 times of that in winter in Beijing, which is approximately consistent with surveyed data. In addition, a novel approach is proposed to assess the human health impact due to pollutants emitted from building materials at varied temperature and relative humidity. An association between the human carcinogenic potential (HCP) and the environmental factors is obtained. By introducing a reference room model developed previously, it is calculated that the HCP of bedroom at high relative humidity (70%, 25°C) for formaldehyde exceeds 10-4 cases, meaning high cancer health risk. This study should prove useful for evaluating the emission behaviors and the associated exposure of pollutants from building materials at varied environmental conditions.

Influence of humidity on the initial emittable concentration of formaldehyde and hexaldehyde in building materials: experimental observation and correlation.

Humidity is one of the main environmental factors affecting the emission rate and key parameters of formaldehyde and volatile organic compounds (VOCs) from building materials. Meanwhile, the initial emittable concentration (Cm,0) is proved to be the most sensitive key parameter to the emission behaviours. However, there is no report on the relationship between humidity and Cm,0. In this paper, Cm,0 of formaldehyde and hexaldehyde from a type of medium density fiberboard in absolute humidity (AH) range of 4.6-19.6 g/m(3) at 25 °C were tested by virtue of a C-history method. Experimental results indicate that Cm,0 is dramatically dependent on AH, increased by 10 and 2 times for formaldehyde and hexaldehyde when AH rising from 4.6 g/m(3) to 19.6 g/m(3). A linear relationship between the logarithm of Cm,0 and AH is obtained based on the measured results. In addition, a correlation characterizing the association of emission rate and AH is derived. The effectiveness of the correlation is verified with our experimental results as well as data from literature. With the correlations, the Cm,0 or emission rate different from the test AH conditions can be conveniently obtained. This study should be useful for predicting the emission characteristics of humidity changing scenarios and for source control.

Impact of temperature on the ratio of initial emittable concentration to total concentration for formaldehyde in building materials: theoretical correlation and validation.

The initial emittable concentration (Cm,0) is a key parameter characterizing the emission behaviors of formaldehyde from building materials, which is highly dependent on temperature but has seldom been studied. Our previous study found that Cm,0 is much less than the total concentration (C0,total, used for labeling material in many standards) of formaldehyde. Because Cm,0 and not C0,total directly determines the actual emission behaviors, we need to determine the relationship between Cm,0 and C0,total so as to use Cm,0 as a more appropriate labeling index. By applying statistical physics theory, this paper derives a novel correlation between the emittable ratio (Cm,0/C0,total) and temperature. This correlation shows that the logarithm of the emittable ratio multiplied by power of 0.5 of temperature is linearly related to the reciprocal of temperature. Emissions tests for formaldehyde from a type of medium density fiberboard over the temperature range of 25.0-80.0 °C were performed to validate the correlation. Experimental results indicated that Cm,0 (or emittable ratio) increased significantly with increasing temperature, this increase being 14-fold from 25.0 to 80.0 °C. The correlation prediction agreed well with experiments, demonstrating its effectiveness in characterizing physical emissions. This study will be helpful for predicting/controlling the emission characteristics of pollutants at various temperatures.

A rapid and accurate method, ventilated chamber C-history method, of measuring the emission characteristic parameters of formaldehyde/VOCs in building materials.

The indoor pollution caused by formaldehyde and volatile organic compounds (VOCs) emitted from building materials poses an adverse effect on people's health. It is necessary to understand and control the behaviors of the emission sources. Based on detailed mass transfer analysis on the emission process in a ventilated chamber, this paper proposes a novel method of measuring the three emission characteristic parameters, i.e., the initial emittable concentration, the diffusion coefficient and the partition coefficient. A linear correlation between the logarithm of dimensionless concentration and time is derived. The three parameters can then be calculated from the intercept and slope of the correlation. Compared with the closed chamber C-history method, the test is performed under ventilated condition thus some commonly-used measurement instruments (e.g., GC/MS, HPLC) can be applied. While compared with other methods, the present method can rapidly and accurately measure the three parameters, with experimental time less than 12h and R(2) ranging from 0.96 to 0.99 for the cases studied. Independent experiment was carried out to validate the developed method, and good agreement was observed between the simulations based on the determined parameters and experiments. The present method should prove useful for quick characterization of formaldehyde/VOC emissions from indoor materials.

A novel method for measuring the diffusion, partition and convective mass transfer coefficients of formaldehyde and VOC in building materials.

The diffusion coefficient (D(m)) and material/air partition coefficient (K) are two key parameters characterizing the formaldehyde and volatile organic compounds (VOC) sorption behavior in building materials. By virtue of the sorption process in airtight chamber, this paper proposes a novel method to measure the two key parameters, as well as the convective mass transfer coefficient (h(m)). Compared to traditional methods, it has the following merits: (1) the K, D(m) and h(m) can be simultaneously obtained, thus is convenient to use; (2) it is time-saving, just one sorption process in airtight chamber is required; (3) the determination of h(m) is based on the formaldehyde and VOC concentration data in the test chamber rather than the generally used empirical correlations obtained from the heat and mass transfer analogy, thus is more accurate and can be regarded as a significant improvement. The present method is applied to measure the three parameters by treating the experimental data in the literature, and good results are obtained, which validates the effectiveness of the method. Our new method also provides a potential pathway for measuring h(m) of semi-volatile organic compounds (SVOC) by using that of VOC.