Increased Lifetime Cancer Risk Research Articles

Comprehensive analysis of nutritive and toxic metal contents in canned tuna: Implications for safety and consumer health

Ca, Mg, K, Na, Fe, Cu, Mn, Zn, Ni, Cr, As, Cd, Pb and Hg levels of canned tuna fish marketed in Turkey were determined by inductively coupled plasma mass spectrometry. Ca content ranged from 80 to 2930 mg/kg, Mg from 900 to 1910 mg/kg, Na from 5930 to 12130 mg/kg, and K from 6930 to 44340 mg/kg. Fe (4.73–27.34 mg/kg), Cu (0.21 and 0.98 mg/kg), Mn (0.12–0.44 mg/kg), Zn (32–45 mg/kg), Ni (0.88–2.06 mg/kg) and Cr (0.03–0.11 mg/kg) contents of the canned foods did not exceed the provisional tolerable weekly intake limit. Cd was detected in two groups (C4=0.02 mg/kg, C18=0.15 mg/kg), while Pb was found in one group (C10=0.48 mg/kg). As content ranged from 0.27 to 1.75 mg/kg in all groups. Most of the tuna cans contained Hg between 0.046 and 0.099 mg/kg, but the highest concentration was found in sample C4 (0.81 mg/kg). Based on the increased lifetime cancer risk findings, the consumption limits of Group 4 and Group 14 should be limited to around 60 g/week (less for children). As a result of the findings that were obtained from this study careful observations should be followed up for the safer consumption of canned tuna.

Measurement of Background Ionizing Radiation Around Beta Glass Plc and Its Environs, Ughelli, Delta State, Nigeria

A study of the background ionizing radiation levels to helps monitor the impact of human activities on the environment, such as mining, farming, glass bottle production and power generation has been carried out around Beta glass Plc and Transcorp Power LTD using a hand-held gamma spectrometer (GAMMA-SCOUT; Geiger counter Radiation meter) and GPS (Oregon-450 Garmin). The study of the BIR levels was carried out between June to July, 2022. The average measured exposure rates (AV. BIR) ranged from 0.007 mRh-1 to 0.013 mRh-1, with 0.010±0.0002 mRh-1 as the average. The estimated mean outdoor absorbed dose rate (ADR) for the study region was 113.10 Gyh-1 to 87.153±2.091 Gyh-1, with an average annual effective dose equivalent (AEDE) of 106.884±2.565 mSvy-1 and an average excess lifetime cancer risk (ELCR) of (0.374±0.009) × 10-3. The measured values of radiological parameters, such as annual dose rate, annual effective dose rate, and excess lifetime cancer, were higher than background radiation levels. The average BIR is in line with the ICRP recommendation of 0.013 (mRh-1), while the effective dose rate (EDR) is somewhat below the ICRP recommendation of 1.00 (mSvy-1) for a normal environment. The obtained values of the radiological indicators, such as ADR, AEDE, and ELCR, are greater than the background radiation norm of 59 (?Gyh-1), 0. 07 (mSvy-1), and 0.29×10-3. The study found that radiation levels and doses in the study location do not immediately harm personnel or residents, but increased lifetime cancer risk values suggest that cumulative dosages may cause cancer.

Spatial Distribution of Gamma Dose Rates and Radioactivity Levels in Some Parts of Iju Community in Ado-Odo Ota, Ogun State

This study investigates the background dose rates and radiological risk exposure to Iju community in Ado-Odo Ota. Using a hand-held calibrated gamma detector (RS-125 Gamma-Spec), the study area’s outdoor gamma dose rates and radionuclide activity concentrations of 40K, 238-U, and 32-Th were measured in situ. The results showed differing activities of the primordial radionuclides (40-K, 238-U, and 232-Th) with average values lying within the recommended limits, with the exception of 40K, which geologically can be caused by regional subsidence while on marine transgression. Based on statistical analysis, the correlation results verified that 40K, 238-U, and 232-Th were the primary causes of the elevated outdoor dose rates at Iju community. The International Commission on Radiological Protection (ICRP) specified allowable limits for radiation exposure, and the estimated mean hazard indices for the increased lifetime cancer risk in the research area exceeded these limitations. In order to ensure sufficient radiation protection, the research area needs attention right away.

Elemental Profile and Health Risk of Fruška Gora Wines.

The elemental composition of wine is influenced by endogenous sources and interventions from winemakers. The ICP-MS analysis of Fruška Gora wines (113) from vintages spanning across a decade (2011-2020), produced by 30 wineries and representing 18 autochthonous and international wine varieties, allowed a comprehensive insight into their elemental composition. Based on the mean concentrations of 23 investigated elements, B, Fe, and Mn, which were determined in mg per L of wine regardless of its colour or origin, were the most abundant. Red and white wines showed significant concentration differences in the case of B, Mn, and Sr (higher in red) as well as Be, Al, V, As, Mo, and Pb (higher in white). The elements of the highest toxicological concern were found in all (Pb and As) or almost all of the samples (Cd and Hg). Pb levels (maximum 47.1, 61.6, and 73.2 μg/L in red, rose, and white, respectively) were well below the legal limit. The applied risk assessment approaches (hazard quotient and index, margin of exposure) revealed no health concerns associated with consumption of Fruška Gora wines, except for a slightly increased lifetime cancer risk in the case of high wine consumption, and thus supported the promotion of Fruška Gora wines in the highly competitive international market.

Source and health risk assessment of soil polycyclic aromatic hydrocarbons under straw burning condition in Changchun City, China

Changchun, China is located in one of the world's three golden corn belts. As a key commodity grain base in China, Changchun plays a vital role in providing food security in the northeast. A total of 16 polycyclic aromatic hydrocarbons (PAHs) was analyzed to determine the influence of anthropogenic activities on the environmental quality of agricultural soils under straw burning conditions. The polycyclic aromatic hydrocarbons soil contamination severity was evaluated using the Maliszewska-Kordybach method. The results indicated that the agricultural soils of Changchun are substantial contaminated with PAHs. Petroleum, biomass, and coal combustion are the primary sources of PAH and have been determined using principal component analysis (PCA) and the isomeric ratio approach. The degree of hazard to human health was assessed using toxicity equivalence and increased lifetime cancer risk (ILCR) factors, except in localized areas during adulthood, the general risk was found to be modest. This study provides important information on PAH exposure in agricultural soils in northeast China, and the findings aid in the exploitation of straw and the mitigation of soil environmental concerns, allowing northeast China to achieve green agricultural development.

Arsenic exposure from drinking water and staple food (rice): A field scale study in rural Bengal for assessment of human health risk

Arsenic is a well-known carcinogen with emerging reports showing a range of health outcomes even for low to moderate levels of exposure. This study deals with arsenic exposure and associated increased lifetime cancer risk for populations in arsenic-endemic regions of rural Bengal, where arsenic-safe drinking water is being supplied at present. We found a median total exposure of inorganic arsenic to be 2. 9 μg/Kg BW/day (5th and 95th percentiles were 1.1 μg/Kg BW/day and 7.9 μg/Kg BW/day); with major contribution from cooked rice intake (2.4 µg/Kg BW/day). A significant number of households drank arsenic safe water but used arsenic-rich water for rice cooking. As a result, 67% participants had inorganic arsenic intake above the JEFCA threshold value of 3 μg/Kg BW/day for cancer risk from only rice consumption when arsenic contaminated water was used for cooking (median: 3.5 μg/Kg BW/day) compared to 29% participants that relied on arsenic-free cooking water (median: 1.0 µg/kg BW/day). Arsenic in urine samples of study participants ranged from 31.7 to 520 µg/L and was significantly associated with the arsenic intake (r = 0.76); confirming the preponderance of arsenic exposure from cooked rice. The median arsenic attributable cancer risks from drinking water and cooked rice were estimated to be 2.4 × 10-5 and 2.7 × 10-4 respectively, which further emphasized the importance of arsenic exposure from staple diet. Our results show that any mitigation strategy should include both drinking water and local staple foods in order to minimize the potential health risks of arsenic exposure.

Relative contribution of rice and fish consumption to bioaccessibility-corrected health risks for urban residents in eastern China

There are global concerns about dietary exposure to metal(loid)s in foods. However, little is known about the relative contribution of rice versus fish to multiple metal(loid) exposure for the general population, especially in Asia where rice and fish are major food sources. We compared relative contributions of rice and fish consumption to multi-metal(loid) exposure on the city-scale (Nanjing) and province-scale in China. The effects of ingestion rate, metal(loid) level, and bioaccessibility were examined to calculate modeled risk from Cu, Zn, total As (TAs), inorganic As (iAs), Se, Cd, Pb, and methylmercury (MeHg). Metal(loid) levels in rice and fish samples collected from Nanjing City were generally low, except iAs. Metal(loid) bioaccessibilities in fish were higher than those in rice, except Se. Calculated carcinogenic risks induced by iAs intake (indicated by increased lifetime cancer risk, ILCR) were above the acceptable level (1 0 −4) in Nanjing City (median: 3 × 10−4 for female and 4 × 10−4 for male) and nine provinces (1.4 × 10−4 to 5.9 × 10−4) in China. Rice consumption accounted for 85.0% to 99.8% of carcinogenic risk. The non-carcinogenic hazard quotients (HQ) for single metals and hazard index (HI) for multi-metal exposure were < 1 in all cases, indicating of their slight non-carcinogen health effects associated. In Guangdong and Jiangsu provinces, results showed that rice and fish intake contributed similarly to the HI (i.e., 42.6% vs 57.4% in Guangdong and 54.6% vs 45.4% in Jiangsu). Sensitivity analysis indicated that carcinogenic risk was most sensitive to rice ingestion rate and rice iAs levels, while non-carcinogenic hazard (i.e., HQ and HI) was most sensitive to ingestion rate of fish and rice, and Cu concentration in rice. Our results suggest that rice is more important than fish for human dietary metal(loid) exposure risk in China, and carcinogenic risk from iAs exposure in rice requires particular attention.

Cross-validation of ultrasound imaging in adolescent idiopathic scoliosis

PurposeAdolescent idiopathic scoliosis (AIS) patients are exposed to 9–10 times more radiation and a fivefold increased lifetime cancer risk. Radiation-free imaging alternatives are needed. Ultrasound imaging of spinal curvature was shown to be accurate, however, systematically underestimating the Cobb angle. The purpose of this study is to create and cross-validate an equation that calculates the expected Cobb angle using ultrasound spinal measurements of AIS patients.MethodsSeventy AIS patients with upright radiography and spinal ultrasound were split randomly in a 4:1 ratio to the equation creation (n = 54) or validation (n = 16) group. Ultrasound angles based on the spinous processes shadows were measured automatically by the ultrasound system (Scolioscan, Telefield, Hong Kong). For thoracic and lumbar curves separately, the equation: expected Cobb angle = regression coefficient × ultrasound angle, was created and subsequently cross-validated in the validation group.ResultsLinear regression analysis between ultrasound angles and radiographic Cobb angles (thoracic: R2 = 0.968, lumbar: R2 = 0.923, p < 0.001) in the creation group resulted in the equations: thoracic Cobb angle = 1.43 × ultrasound angle and lumbar Cobb angle = 1.23 × ultrasound angle. With these equations, expected Cobb angles in the validation group were calculated and showed an excellent correlation with the radiographic Cobb angles (thoracic: R2 = 0.959, lumbar: R2 = 0.936, p < 0.001). The mean absolute differences were 6.5°–7.3°. Bland–Altman plots showed good accuracy and no proportional bias.ConclusionThe equations from ultrasound measurements to Cobb angles were valid and accurate. This supports the implementation of ultrasound imaging, possibly leading to less frequent radiography and reducing ionizing radiation in AIS patients.

Arsenic exposure from food exceeds that from drinking water in endemic area of Bihar, India

Extensive evidence of elevated arsenic (As) in the food-chain, mainly rice, wheat and vegetables exists. Nevertheless, the importance of exposure from food towards total As exposure and associated health risks in areas with natural occurring As in drinking water is still often neglected, and accordingly mitigations are largely focused on drinking water only. In this study, the contribution of food over drinking water to overall As exposure was estimated for As exposed populations in Bihar, India. Increased lifetime cancer risk was predicted using probabilistic methods with input parameters based on detailed dietary assessment and estimation of As in drinking water, cooked rice, wheat flour and potato collected from 91 households covering 19 villages. Median total exposure was 0.83 μg/kgBW/day (5th and 95th percentiles were 0.21 and 11.1 μg/kgBW/day) and contribution of food (median = 49%) to overall exposure was almost equal to that from drinking water (median = 51%). More importantly and contrary to previous studies, food was found to contribute more than drinking water to As exposure, even when drinking water As was above the WHO provisional guide value of 10 μg/L. Median and 95th percentile excess lifetime cancer risks from food intake were 1.89 × 10−4 and 7.32 × 10−4 respectively when drinking water As was below 10 μg/L and 4.00 × 10−4 and 1.83 × 10−3 respectively when drinking water As was above 10 μg/L. Our results emphasise the importance of food related exposure in As-endemic areas, and, perhaps surprisingly, particularly in areas with high As concentrations in drinking water – this being partly ascribed to increases in food As due to cooking in high As water. These findings are timely to stress the importance of removing As from the food chain and not just drinking water in endemic areas.

Hydraulic conductivity and porosity heterogeneity controls on environmental performance metrics: Implications in probabilistic risk analysis

Heterogeneities in natural porous formations, mainly manifested through the hydraulic conductivity (K) and, to a lesser degree, the porosity (ϕ), largely control subsurface flow and solute transport. The influence of the heterogeneous structure of K on transport processes has been widely studied, whereas less attention is dedicated to the joint heterogeneity of conductivity and porosity fields. Our study employs Monte Carlo simulations to investigate the coupled effect of K−ϕ spatial variability on the transport behavior (and uncertainty) of conservative and reactive plumes within a 3D aquifer domain. We explore multiple scenarios, characterized by different levels of heterogeneity of the geological properties, and compare the computational results from the joint K−ϕ heterogeneous system with the results originating from generally adopted constant ϕ conditions. In our study, the spatially variable K−ϕ fields are positively correlated. We statistically analyze key Environmental Performance Metrics: first arrival times and peak mass fluxes for non-reactive species and increased lifetime cancer risk for reactive chlorinated solvents. The conservative transport simulations show that considering coupled K−ϕ fields decreases the plume dispersion, increases both the first arrival times of solutes and the peak mass fluxes at the observation planes. A positive correlation between aquifer connectivity and peak mass fluxes is identified for both homogeneous and heterogeneous ϕ. Our conservative transport results indicate that the relevance of ϕ variability can depend on the metric of interest, the control plane-source distance as well as the level of heterogeneity of the conductivity field. The analysis on reactive transport shows that ϕ variability only slightly affects the mean increased lifetime cancer risk at the control planes but leads to a considerable reduction of the cancer risk uncertainty. We also see that the sensitivity of cancer risk towards ϕ heterogeneity can be influenced by the level of variability of the conductivity field, the source-to-control plane distance, but is not affected by the manner in which the contaminant concentration is computed.

Whole body magnetic resonance imaging (WB-MRI) and brain MRI baseline surveillance in TP53 germline mutation carriers: experience from the Li-Fraumeni Syndrome Education and Early Detection (LEAD) clinic.

Individuals with Li-Fraumeni syndrome (LFS) have a significantly increased lifetime cancer risk affecting multiple organ sites. Therefore, novel comprehensive screening approaches are necessary to improve cancer detection and survival in this population. The objective of this study was to determine the diagnostic performance of whole body MRI (WB-MRI) and dedicated brain MRI screening as part of a comprehensive screening clinic called Li-Fraumeni Education and Early Detection (LEAD) at MD Anderson Cancer Center. Adult (≥21year old) and pediatric (<21year old) patients were referred to the LEAD clinic by healthcare providers or self-referred and screened at 6month intervals. During the study period, 63 LFS individuals were seen in the LEAD clinic including 49 adults (11 male, 38 female) and 14 children (7 male, 7 female). Fifty-three of 63 potentially eligible individuals underwent baseline WB-MRI (41 adults and 12 children) with primary tumors detected in six patients, tumor recurrence in one patient and cancer metastases in one patient. Thirty-five of 63 patients (24 adults and 11 children) underwent baseline brain MRI with primary brain tumors detected in three individuals, also noted on subsequent WB-MRI scans. Three additional tumors were diagnosed that in retrospect review were missed on the initial scan (false negatives) and one tumor noted, but not followed up clinically, was prospectively found to be malignant. The high incidence of asymptomatic tumors identified in this initial screening (13%), supports the inclusion of WB-MRI and brain MRI in the clinical management of individuals with LFS.

PAH concentrations in sediment from Jones Creek Delta State, Nigeria: distribution and lifetime cancer risks

Concentrations of the sixteen USEPA and Water Framework Directive (2006/60/EC) priority pollutants - polycyclic aromatic hydrocarbons (PAHs) in sediment and shrimp samples in Jones Creek southern Nigeria was investigated from March 2015 to August 2016. The ΣPAHs ranged from 0.32±0.07 to 48.38± 2.47 mg/kg for sediment samples collected for the 18month duration of this study. The PAH concentrations obtained in the sediment suggest the dominance of the high molecular weight pollutants (benzo[a]anthracene) indicative of a pyrolytic source. Assessment of the cancer potential risk using the Increased Lifetime Cancer Risk (ILCR) indicated a high exposure potential for the sampling location. Several of them are known carcinogens including benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[a]pyrene and benzo[g,h.i]perylene. Diagnostic ratios such as phenanthrene/anthracene and fluoranthene/pyrene were employed to evaluate the emission sources of PAHs. These ratios indicated a pyrolytic source of PAHs for sediments obtained within the study area.Keywords: PAHs, sediment, cancer risk, diagnostic ratio, ILCR

Radiation dose awareness and disclosure practice in paediatric emergency medicine: how far have we come?

The past decade has brought increasing coverage in the medical literature and lay media of the potential association between low-level radiation from diagnostic imaging and an increased lifetime cancer risk. Both physician and public opinion increasingly favour a greater discussion of benefit and risk with patients and their families when such imaging is being considered. Particular attention has been directed towards CT, its use in children and the emergency department setting. We will review the evolution of radiation dose awareness and knowledge among emergency physicians (EPs) alongside the parallel increase in public awareness. We will then discuss expectations for risk disclosure and the challenges faced by EPs and radiologists as we strive to provide this in a clinically balanced and meaningful way.

Retrospective analysis of incidental non-trauma associated findings in severely injured patients identified by whole-body spiral CT scans.

BackgroundWhole-body Computed Tomography (CT) scan today is considered a crucial imaging technique in the diagnostic work-up of polytrauma patients implicating a potential survival benefit. Apart from prompt identification of life threatening injuries this imaging technique provides an additional benefit by diagnosing incidental non-trauma associated medical diseases. These incidental findings might be also life threatening and warrant urgent therapy. The downside of whole-body CT is a relatively high radiation exposure that might result in an increased life time cancer risk. The aim of this study was to investigate the frequency and type of non trauma associated incidental medical findings in relation to patient age and potential clinical relevance.MethodsBetween January 1st 2011 and December 15th 2012, a total of 704 trauma patients were referred to our hospital’s emergency room that triggered trauma room alarm according to our trauma mechanism criteria. Of these 534 (75.8%) received a whole-body CT according to our dedicated multiple trauma protocol. Incidental Findings (IF) were assigned in three groups according to their clinical relevance. Category 1: IF with high medical relevance (urgent life threatening conditions, unless treated) needing early investigations and intervention prior to or shortly after hospital discharge. Category 2: IF with intermediate or low medical relevance, warranting further investigations. Category 3: IF without clinical relevance.ResultsOverall 231 IFs (43.3%) were identified, 36 (6.7%) patients had IFs with a high clinical relevance, 48 (9.0%) with a moderate or minor clinical relevance and 147 (27.5%) with no clinical relevance. The distribution of incidental findings with high or moderate relevance according to age showed an incidence of 2.6%, 6.6% and 8.8% for patients younger than 40 years, 40 to 60 years and older than 60 years, respectively.ConclusionWhole-body CT scans of trauma patients demonstrate a high rate of incidental findings. Potentially life-threatening, medical findings were found in approximately every 15th patient, predominantly aged over 40 years and presenting with minor to moderate injuries and an Injury Severity Score (ISS) of 10 or less.

Residues and chiral signatures of organochlorine pesticides in mollusks from the coastal regions of the Yangtze River Delta: Source and health risk implication

The residues and enantiomeric fractions of organochlorine pesticides (OCPs) were measured in 11 mollusk species collected from the coastal areas along the Yangtze River Delta to evaluate the status, potential sources, and health risks of pollution in these areas. The concentrations of DDTs, HCHs, and chlordanes ranged from 6.22 to 398.19, 0.66–7.11, and 0.14–4.08ngg−1 based on wet weight, respectively; DDTs and HCHs have the highest values, globally. The DDTs increased and the HCHs decreased compared to historical data. Both the box-and-whisker plots and the one-way ANOVA tests indicated that the OCP levels varied little between sampling locations and organism species. The compositions of the DDTs and HCHs suggested a cocktail input pattern of fresh and weathered technical products. The comparative EF values for the α-HCH between the sediments and mollusks, as well as the lack of any discernible difference in the relative proportions of HCH isomers among different species from the same sampling site implied that the HCH residues in the mollusks came directly from the surrounding environment. However, the biotransformation of DDTs in mollusks cannot be precluded. The assessments performed based on several available guidelines suggested that although no significant human health risks were associated with the dietary intake of OCPs, the concentrations of DDTs exceeded the maximum residual limits of China and many developed nations. Moreover, an increased lifetime cancer risk from dietary exposure to either DDTs or HCHs remains a possibility. Because non-racemic OCP residues are common in the mollusk samples, our results suggest a need to further explore the levels and toxicity of the chiral contaminants in mollusks and other foodstuff to develop the human risk assessment framework based on chiral signatures.

The Predicted Increased Cancer Risk Associated With a Single Computed Tomography Examination for Calculus Detection in Pediatric Patients Compared With the Natural Cancer Incidence

The objective of the study was to estimate the increased lifetime cancer risk associated with a single computed tomography (CT) examination for calculus detection in pediatric patients and compare it with the lifetime natural cancer risk. We used the program CT-Expo to calculate the radiation doses to various abdominal and pelvic organs for age-appropriate pediatric renal stone CT examination protocols used at our institution. Using the Biological Effects of Ionizing Radiation (BEIR) VII report, we estimated the lifelong cancer risk for these organs and compared it with the natural cancer risk for the same organs as predicted by the Surveillance, Epidemiology and End Results data from the National Cancer Institute. For children 10 years or younger at the time of the examination, about 3 radiation-induced cancers are predicted for every 1000 naturally occurring cancers, and for children 15 years old, about 2 radiation-induced cancers are predicted for every 1000 naturally occurring cancers. The radiation dose from this examination is approximately equivalent to 1 to 2 years of background radiation. The ratio of the risk for any abdominal and pelvic cancer due to a single CT examination for calculus detection to the risk of a naturally occurring cancer over the lifetime of a child is estimated to be 2/1000 to 3/1000. With this information, the emergency department pediatrician can more effectively counsel parents about the risk-benefit aspects of the CT examination for renal calculus disease in their children.

Integrated exposure assessment of sewage workers to genotoxicants: an urinary biomarker approach and oxidative stress evaluation

BackgroundSewage workers are exposed to multiple chemicals among which many are suspected genotoxicants. Therefore, they might incur DNA damage and oxidative stress. We aimed to explore integrated urinary biomarkers, assessing the overall urine genotoxicity by in vitro comet and micronucleus assays and measuring urinary 8-oxo-2'-deoxyguanosine.MethodsDuring three consecutive working days, polycyclic aromatic hydrocarbons and volatile organic compounds were sampled in workplace air of 34 sewage and 30 office workers, as indicators of airborne exposure. The last day, subjects collected their 24 hours urine. Genotoxicity of urinary extracts was assessed by comet and micronucleus assays on a HepG2 cell line. Using competitive enzymatic immunoassay we evaluated the 24 hours urinary 8-oxo-2'-deoxyguanosine excretion. Benzo(a)pyrene toxicity equivalent factors and inhalation unit risk for Benzo(a)pyrene and benzene were used to give an estimate of cancer risk levels.ResultsWorkplace air concentrations of polycyclic aromatic hydrocarbons (e.g. 23.7 [range 2.4-104.6] ng.m-3 for fluoranthene) and volatile organic compounds (e.g. 19.1 ± 2.9 [standard error] μ.m-3 for benzene) were elevated in sewage compared to office workplaces (P < 0.01) and corresponded to an increased lifetime cancer risk. The urinary extracts of sewage workers showed higher genotoxicity (P < 0.001) than office workers.ConclusionsThe integrated and non-specific urinary biomarkers of exposure showed that sewage workers experience exposure to mixtures of genotoxicants in the workplace.

Patient Perceptions of Computed Tomographic Imaging and Their Understanding of Radiation Risk and Exposure

We describe patient perceptions of computed tomography (CT) and their understanding of radiation exposure and risk. This was a cross-sectional study of acute abdominal pain patients aged 18 years or older. Confidence in medical evaluations with increasing levels of laboratory testing and imaging was rated on a 100-point visual analog scale. Knowledge of radiation exposure was ascertained when participants compared the radiation dose of one abdomen-pelvis CT with 2-view chest radiography. To assess cancer risk knowledge, participants rated their agreement with these factual statements: "Approximately 2 to 3 abdominal CTs give the same radiation exposure as experienced by Hiroshima survivors" and "2 to 3 abdominal CTs over a person's lifetime can increase cancer risk." Previous CT was also assessed. There were 1,168 participants, 67% women and mean age 40.7 years (SD 15.9 years). Median confidence in a medical evaluation without ancillary testing was 20 (95% confidence interval [CI] 16 to 25) compared with 90 (95% CI 88 to 91) when laboratory testing and CT were included. More than 70% of participants underestimated the radiation dose of CT relative to chest radiography, and cancer risk comprehension was poor. Median agreement with the Hiroshima statement was 13 (95% CI 10 to 16) and 45 (95% CI 40 to 45) with the increased lifetime cancer risk statement. Seven hundred ninety-five patients reported receiving a previous CT. Of 365 patients who reported no previous CT, 142 (39%) had one documented in our electronic medical record. Patients are more confident when CT imaging is part of their medical evaluation but have a poor understanding of the concomitant radiation exposure and risk and underestimate their previous imaging experience.

Rice is a major exposure route for arsenic in Chakdaha block, Nadia district, West Bengal, India: A probabilistic risk assessment

The importance or otherwise of rice as an exposure pathway for As ingestion by people living in Bengal and other areas impacted by hazardous As-bearing groundwaters is currently a matter of some debate. Here this issue is addressed by determining the overall increased cancer risk due to ingestion of rice in an As-impacted district of West Bengal. Human target cancer health risks have been estimated through the intake of As-bearing rice by using combined field, laboratory and computational methods. Monte Carlo simulations were run following fitting of model probability curves to measured distributions of (i) As concentration in rice and drinking water and (ii) inorganic As content of rice and fitting distributions to published data on (i) ingestion rates and (ii) body weight and point estimates on bioconcentration factors, exposure duration and other input variables. The distribution of As in drinking water was found to be substantially lower than that reported by previous authors for As in tube wells in the same area, indicating that the use of tube well water as a proxy for drinking water is likely to result in human health risks being somewhat overestimated. The calculated median increased lifetime cancer risk due to cooked rice intake was 7.62 x10 -4, higher than the 10-4–10-6 range typically used by the USEPA as a threshold to guide determination of regulatory values and similar to the equivalent risk from water intake. The median total risk from combined rice and water intake was 1.48x10-3. The contributions to this median risk from drinking water, rice and cooking of rice were found to be 48%, 44% and 8%, respectively. Thus, rice is a major potential source of As exposure in the As-affected study areas in West Bengal and the most important exposure pathway for groups exposed to low or no As in drinking water.

The Cancer Differential: Minorities in Racially Segregated Urban Areas at Higher Risk than Whites

Nearly 80% of the U.S. population lives in metropolitan areas. With continued growth of urban centers has come increased study of the connection between the built environment, social inequality, and the health and well-being of inhabitants of these large cities. A number of factors related to neighborhood location and other area-level variables such as access to nutritious foods and health care can affect human health. Now a research team points to another health consideration, demonstrating that minority populations living in highly segregated metropolitan areas in the United States have higher estimated lifetime cancer risks from air toxics than whites [EHP 114:386–393; Morello-Frosch et al.]. The team analyzed more than 45,000 census tracts in 309 U.S. metropolitan areas for level of segregation. The metropolitan areas were classified as low-to-moderately segregated, highly segregated, or extremely segregated, based on the proportion of people who would have to move to achieve an even racial balance in every neighborhood of the city. They also used census data to divide racial and ethnic groups into six categories: Hispanics of any race, non-Hispanic whites, non-Hispanic blacks, non-Hispanic Asians and Pacific Islanders, non-Hispanic American Indians and Alaska Natives, and non-Hispanic persons of other race. Then the team used federal air toxics data for 1996 to derive cancer risk estimates. Cancer risks were determined using inhalation unit risk estimates for each known, likely, or potential human carcinogen measured in the tracts’ air. Inhalation unit risk estimates consider the individual lifetime excess risk resulting from chronic lifetime exposure to one unit of pollutant concentration. The researchers found a persistent relationship between increasing levels of racial/ethnic segregation and increased estimated cancer risk associated with ambient air toxics. Hispanics in extremely segregated areas were the most affected, with a 6.4-fold increased lifetime cancer risk compared to Hispanics in low-to-moderately segregated areas. Non-Hispanic American Indians and Alaska Natives in highly segregated areas were the least affected, with a 1.39-fold increased risk over their counterparts in low-to-moderately segregated areas. The influence of racial segregation on cancer risk appeared independent of the effect of poverty across racial categories. The most significant contributors to cancer risk were mobile sources such as on-road vehicles, airplanes, and trains, with diesel emissions an overwhelming source of pollution. The authors note that these results are consistent with findings from a previous national study that analyzed the relationship between black/white residential segregation and ambient air toxic exposure in U.S. metropolitan areas. They believe this study to be the first examination of environmental health disparities to use a generalized multiethnic segregation measure. They assert that future research on this issue that incorporates new and better models of exposure should include segregation as a key factor in analysis.