Indirect Exposure Group Research Articles

Serum vitamin D concentrations in rabbits (Oryctolagus cuniculus) are more affected by UVB irradiation of food than irradiation of animals

Rabbits kept under ultraviolet B (UVB)-irradiation respond with increasing serum vitamin D (25(OH)D) concentrations, but it is unknown whether irradiation of the animals or their feed contributes more. Twenty-four New Zealand White rabbits were divided into three groups for a four-week period: the control group (C) received no UVB-exposure and non-irradiated hay (ergocalciferol (vitamin D2) concentration 2.22 µg/100 g dry matter). The direct exposure group (D) was provided with 12 h of UVB-irradiation daily and fed the same hay as group C in shaded areas to prevent UVB-irradiation thereof. The indirect exposure group (I) did not receive direct UVB-irradiation but was fed hay of the same batch that was exposed to 12 h of UVB-irradiation (vitamin D2 6.06 µg/100 g dry matter). Serum 25(OH)D2, 25(OH)D3, ionised calcium, total calcium, phosphorus, and magnesium concentrations were measured weekly. There was no systematic effect on serum mineral concentrations. The serum 25(OH)D2 concentrations were significantly higher in group I compared to groups C and D from the second week onwards. 25(OH)D3 concentrations increased only in group D, with significant differences to both other groups from the third week onwards, yet at lower magnitudes than the noted increase of 25(OH)D2 in group I. Total 25(OH)D concentrations were highest in group I, intermediate in group D and lowest in group C. Serum total 25(OH)D concentration was more affected by UVB-irradiation of rabbits’ feed than by direct irradiation of the animals themselves. If rabbit serum total 25(OH)D concentrations should be managed, diet manipulation rather than animal UVB-exposure appears to be more effective.

Study the effect of cement dust exposure on the hematological variables in the workers of new badoosh cement factory in mosul city, Iraq

The present study was carried in the New Badoosh Cement factory in Mosul city belonged to Ministry of Industry and Minerals/Iraq. The continuous exposure to cement dustleads to many respiratory and health problems. So the current study aimed to determine the negative effects of this dust and the continuous exposure to them in hematological variables in the blood of 150 workers of non-smoking males working, by 25 blood samples for each of the units and productive stages as following: The administrative unit (indirect exposure group), and the groups of the productive stages (direct exposure), which included stage of mechanical workshop, material milling, ovens, cement milling and packing. Their ages ranged between (23-59)years, exposure periods were divided according to the working years into (5-10), (11-20) and ( >20 ) years, then comparison with 30 healthy, non-smoking males of the same age as workers residents in the Rabea sub-district (Al-Owainat village) outside the city and were used as a control group. The results showed a significant decrease in the hemoglobin concentration (Hb), packed cell volume (PCV%)andred blood cells count (RBCs). Also the results showed a significant increase in count of white blood cells (WBCs), lymphocytes and granules in the blood of workers inadministrators (indirect exposure group) and indifferent productive stages (direct exposure group) during the three exposure periods, as these results showed that different exposure periods and special ( >20 ) years had a clear effect on these studied blood components. It is concluded from this study that exposure of workers in different productive stages and administrative unit to cement dusthas caused clear negative effects on the blood components with an increase in the exposure period and a disrupted in metabolic and physiological processes.

Comparison of whole blood indium and the serum indium of the population exposed to the indium

Objective: The method was established for the detection of whole blood indium and serum indium. By comparing the results of two samples, it is possible to explore the significance of whole blood indium and serum indium in the population exposed to indium compounds. Methods: According to GBZ/T 295-2017 and GBZ 294-2017, the whole blood and serum samples were diluted 20 times by 0.5% nitric acid solution (including 0.05% Triton X-100) . Under the standard mode of inductively coupled plasma mass spectrometry (ICP-MS) , whole blood indium and serum indium of indirect exposure group, low exposure group and high exposure group in an indium mine were detected with 20 μg/L rhodium standard solution as internal standard. Results: This method has a working range of 0.00~5.00 μg/L and a correlation coefficien t>0.999. The detection limit and quantitative lower limit of whole blood indium were 0.076 μg/L and 0.26 μg/L respectively. Those of serum indium were 0.06 μg/L and 0.20 μg/L accordingly. The recovery rates of serum and whole blood samples were 88.5%~95.6% and 93.0%~101%. Intra batch precisions were 1.3%~4.4% and 1.9%~3.5% and inter batch precision were 2.4%~6.1% and 2.1%~4.6% in two samples. There were no significant differences between whole blood indium and serum indium in indirect exposure group. The serum indium level was lower than the detection limit in 3 cases, while their whole blood indium was only below the quantitative lower limit. However, in other groups whole blood indium level was significantly higher than serum indium level (P<0.05) and even was two-fold in the high exposure group. Conclusion: The detection of whole blood indium is more sensitive than that of serum indium, which can reflect the internal exposure level more accurately in exposure population. Therefore, the whole blood indium is of more important referential value to health examination and poisoning diagnosis in the population exposed to indium and its compounds.

Exposure to the Chinese famine in early life and depression in adulthood

We aimed to investigate whether exposure to the Chinese famine (1959–1961) in early life was associated with depression in adulthood. We included 17,505 participants from the China health and retirement longitudinal study (CHARLS). Participants were classified into indirect and direct exposure groups. And the directly exposure groups including prenatal, childhood, adolescence/adult exposure groups. Depression was diagnosed by Center for Epidemiological Studies Depression Scale-10 (CES-D) score. Multivariate logistic regression model was used to calculate the odd ratios (ORs) and 95% confidence intervals (CIs) of depression. In women, prenatal, childhood, adolescence/adult exposure groups had higher depression risk than indirect exposure group (OR = 1.46, 1.40, and 1.67, respectively). However, there was no significant association between famine exposure and depression among men. Exposure to famine during prenatal (OR: 1.48; 95% CI: 1.07–2.06), childhood (OR: 1.47; 95% CI: 1.13–1.91), and adolescence/adult (OR: 1.63; 95% CI: 1.24–2.15) period were associated with depression among subjects living in rural, but not those living in urban. Exposure to the Chinese famine in early life had sex and area-specific associations with depression.

Cognitive impairment in agricultural workers and nearby residents exposed to pesticides in the Coquimbo Region of Chile

Chronic exposure to organophosphate pesticides is a worldwide public health concern associated with several psychiatric disorders and dementia. Most existing studies on the effects of pesticides only evaluate agricultural workers. Therefore, this study sought to establish if individuals indirectly exposed to pesticides, such as residents in agricultural areas, also suffer cognitive impairments. Neuropsychological evaluations were carried out on three groups (n=102): agricultural workers directly exposed to pesticides (n=32), individuals living in agricultural areas indirectly (i.e. environmentally) exposed to pesticides (n=32), and an unexposed control group (n=38). The assessed cognitive processes included memory, executive functions, attention, language praxis, and visuoconstruction. The direct exposure group performed significantly lower in executive function, verbal fluency, and visual and auditory memory tests than the indirect exposure group, which, in turn, performed worse than the unexposed group. Even after adjusting for age, gender, and educational level, both exposure groups showed higher rates of cognitive deficit than control individuals. In conclusion, both direct and indirect chronic exposure to pesticides affects cognitive functioning in adults and, consequently, actions should be taken to protect the health of not only agricultural workers, but also of residents in agricultural areas.

Holocaust exposure and subsequent suicide risk: a population-based study.

To examine the association between the extent of genocide exposure and subsequent suicide risk among Holocaust survivors. Persons born in Holocaust-exposed European countries during the years 1922-1945 that immigrated to Israel by 1965 were identified in the Population Registry (N=209,429), and followed up for suicide (1950-2014). They were divided into three groups based on likely exposure to Nazi persecution: those who immigrated before (indirect; n=20,229; 10%), during (partial direct; n=17,189; 8%), and after (full direct; n=172,061; 82%) World War II. Groups were contrasted for suicide risk, accounting for the extent of genocide in their respective countries of origin, high (>70%) or lower levels (<50%). Cox model survival analyses were computed examining calendar year at suicide. Sensitivity analyses were recomputed for two additional suicide-associated variables (age and years since immigration) for each exposure group. All analyses were adjusted for confounders. Survival analysis showed that compared to the indirect exposure group, the partial direct exposure group from countries with high genocide level had a statistically significant (P<.05) increased suicide risk for the main outcome (calendar year: HR 1.78, 95% CI 1.09, 2.90). This effect significantly (P<.05) replicated in two sensitivity analyses for countries with higher relative levels of genocide (age: HR 1.77, 95% CI 1.09, 2.89; years since immigration: HR 1.85, 95% CI 1.14, 3.02). The full direct exposure group was not at significant suicide risk compared to the indirect exposure group. Suicide associations for groups from countries with relative lower level of genocide were not statistically significant. This study partly converges with findings identifying Holocaust survivors (full direct exposure) as a resilient group. A tentative mechanism for higher vulnerability to suicide risk of the partial direct exposure group from countries with higher genocide exposure includes protracted guilt feelings, having directly witnessed atrocities and escaped death.

Genocide Exposure and Subsequent Suicide Risk: A Population-Based Study.

The association between periods of genocide-related exposures and suicide risk remains unknown. Our study tests that association using a national population-based study design. The source population comprised of all persons born during1922-1945 in Nazi-occupied or dominated European nations, that immigrated to Israel by 1965, were identified in the Population Register (N = 220,665), and followed up for suicide to 2014, totaling 16,953,602 person-years. The population was disaggregated to compare a trauma gradient among groups that immigrated before (indirect, n = 20,612, 9%); during (partial direct, n = 17,037, 8%); or after (full direct, n = 183,016, 83%) exposure to the Nazi era. Also, the direct exposure groups were examined regarding pre- or post-natal exposure periods. Cox regression models were used to compute Hazard Ratios (HR) of suicide risk to compare the exposure groups, adjusting for confounding by gender, residential SES and history of psychiatric hospitalization. In the total population, only the partial direct exposure subgroup was at greater risk compared to the indirect exposure group (HR = 1.73, 95% CI, 1.10, 2.73; P < .05). That effect replicated in six sensitivity analyses. In addition, sensitivity analyses showed that exposure at ages 13 plus among females, and follow-up by years since immigration were associated with a greater risk; whereas in utero exposure among persons with no psychiatric hospitalization and early postnatal exposure among males were at a reduced risk. Tentative mechanisms impute biopsychosocial vulnerability and natural selection during early critical periods among males, and feelings of guilt and entrapment or defeat among females.

Exposure to genocide and the risk of schizophrenia: a population-based study.

No evidence exists on the association between genocide and the incidence of schizophrenia. This study aims to identify critical periods of exposure to genocide on the risk of schizophrenia. This population-based study comprised of all subjects born in European nations where the Holocaust occurred from 1928 to 1945, who immigrated to Israel by 1965 and were indexed in the Population Register (N = 113 932). Subjects were followed for schizophrenia disorder in the National Psychiatric Case Registry from 1950 to 2014. The population was disaggregated to compare groups that immigrated before (indirect exposure: n = 8886, 7.8%) or after (direct exposure: n = 105 046, 92.2%) the Nazi or fascist era of persecutions began. The latter group was further disaggregated to examine likely initial prenatal or postnatal genocide exposures. Cox regression modelling was computed to compare the risk of schizophrenia between the groups, adjusting for confounders. The likely direct group was at a statistically (p < 0.05) greater risk of schizophrenia (hazard ratio = 1.27, 95% confidence interval 1.06-1.51) than the indirect group. Also, the likely combined in utero and postnatal, and late postnatal (over age 2 years) exposure subgroups were statistically at greater risk of schizophrenia than the indirect group (p < 0.05). The likely in utero only and early postnatal (up to age 2 years) exposure subgroups compared with the indirect exposure group did not significantly differ. These results were replicated across three sensitivity analyses. This study showed that genocide exposure elevated the risk of schizophrenia, and identified in utero and postnatal (combined) and late postnatal (age over 2 years) exposures as critical periods of risk.

A Study on the Mediating Effect of Social Sharing on the Relationship between Memory Characteristics and Event Centrality Regarding Social crisis: Comparison between Perceived Direct Exposure Group and Indirect Exposure Group

본 연구의 목적은 한국의 주요 사회적 위기사건들에 대한 개개인의 기억특성이 사건 중심성에 영향을 미치는 과정에 사회적 공유가 중요한 매개요인으로 기능하고 있음을 검증하고, 사회적 위기사건에 직접 노출된 집단과 간접 노출된 집단 간 차이를 분석하는데 있다. 이를 위해 전국 성인 1065명을 대상으로 제시한 한국의 주요 사회적 사건 목록 중 개인적으로 가장 기억에 남는 한 가지 사건을 정하도록 하고, 그 사건에 대한 기억특성 및 사회적 공유(Memory Experience Questionnaire), 사건 중심성(Centrality of Event Scale)을 측정 하였다. 본 연구에는 사회적 위기사건을 가장 기억에 남는 사건으로 선택한 818명의 자료만을 분석에 사용하였다. 이후 ‘자신이 선택한 사건을 직접 경험했는지’를 묻는 문항에 응답한 내용을 바탕으로 818명의 자료를 지각된 직접 노출집단(N=286)과 간접 노출집단(N=532)으로 구분하였다. 두 집단에서 연구모형에 유의한 경로계수 차이를 보이는지 검증한 결과, 지각된 직접 노출집단에서는 생생함과 사건 중심성 간 관계에서 사회적 공유가 유의한 매개효과를 가지지 않았다. 반면, 간접 노출집단에서는 생생함이 사회적 공유를 완전 매개하여 사건 중심성에 영향을 미쳤다. 정서강도는 두 집단 모두에서 사회적 공유의 부분 매개효과가 유의했으며, 지각된 직접 노출집단에서 정서강도와 사회적 공유의 직접 관계가 더욱 높았다. 부정정서의 경우, 지각된 직접 노출집단에서는 사회적 공유가 부정정서 수준과 사건 중심성 간의 관계를 완전 매개하고 있는 반면, 간접 노출집단에서는 사회적 공유의 매개효과가 유의하지 않았고, 직접 사건 중심성에 영향을 주고 있었다. 본 연구 결과를 토대로 연구의 의의와 제한점을 기술하고 후속 연구에 대한 제안을 논의하였다.

Pulmonary function tests in Petrol pump workers in Karad town

Objectives: Polluted environment at petrol pumps is likely to have adverse effects on health of workers. Petrol filling workers as well as office workers at petrol pumps are likely to have adverse effects on lung function. We wanted to study the actual fact. Methods: Pulmonary function tests were studied in petrol pump workers in Karad city and around. Petrol filling workers (direct exposure group, 48) and petrol pump office workers (indirect exposure group, 12) were included in study. Control group (50) of age matched healthy paramedical workers from KIMS, University was included. Approval from Institutional Ethical Committee was obtained. Informed written consent was taken from each participant. Spirometric lung function test were carried out in department of Physiology. Pulmonary function parameters included were FVC (Forced Vital Capacity), FEV1 (Forced Expiratory Volume in First second of FVC), FEV1% (FEV1 as % of FVC), PEFR (Peak Expiratory Flow Rate in liters/sec), FEF25-75% (Forced Expiratory Flow Rate during 25 to 75 % of expiration), FEF 0.2-1.2 (Forced Expiratory Flow between 0.2 -1.2 liters of expiration) and MVV (Maximum Voluntary Ventilation). After computing mean and SD of each parameter group comparison was done by using paired t test and ANOVA. Results: Impairment of lung function (Predominantly restrictive type) was found in both the study groups compared to controls. Conclusions: Exposure to polluted air and fumes of petrol/diesel causes lung function derangement in petrol pump workers.

A 6-Month Follow-Up Study of Posttraumatic Stress and Anxiety/Depressive Symptoms in Korean Children After Direct or Indirect Exposure to a Single Incident of Trauma

The aims of this study were to examine the symptoms of posttraumatic stress and anxiety/depression in Korean children after direct or indirect exposure to a single incident of trauma during a fire-escape drill and to assess the incidence of psychiatric disorders in this population. A total of 1,394 students who attended the elementary school at which the traumatic event took place were evaluated using self-administered questionnaires (the Child Posttraumatic Stress Disorder-Reaction Index [CPTSD-RI], State Anxiety Scale of the State-Trait Anxiety Inventory for Children [STAIC], and Children's Depression Inventory [CDI]), as well as structured diagnostic interviews (Diagnostic Interview Schedule for Children, Version-IV [DISC-IV]) at 2 days (time point 1), 2 months (time point 2), and 6 months (time point 3) after the incident. The 335 students who witnessed the accident were defined as the direct-exposure group, and the remaining students (n = 1,059) were defined as the indirect-exposure group. The study was conducted from May to November 2007. At time point 1, the prevalence of severe posttraumatic stress disorder (PTSD), anxiety, and depressive symptoms was 18.2%, 5.5%, and 3.4%, respectively. The prevalence of severe PTSD symptoms, as measured by the CPTSD-RI, was significantly higher in the direct-exposure group than in the indirect-exposure group (36.6% vs 12.7%, respectively; P < .001). At time point 2, the prevalence of severe PTSD symptoms was 7.4% (14.0% in the direct-exposure group and 4.9% in the indirect-exposure group, P < .001). The mean total CPTSD-RI score was significantly higher (P < .001) in the direct-exposure group than in the indirect-exposure group. At time point 3, thirty-eight of the 58 subjects (65.5%) evaluated with the DISC-IV in the direct-exposure group had 1 or more of the 7 anxiety/depressive disorders assessed, including subthreshold diagnoses. Among the diagnoses meeting full DSM-IV criteria for each disorder, agoraphobia was the most prevalent (22.4%), followed by generalized anxiety disorder (13.8%), separation anxiety disorder (6.9%), PTSD (5.2%), and social phobia (5.2%). When the subthreshold diagnoses were considered along with the full syndrome diagnoses, separation anxiety disorder was the most common diagnosis (41.4%), followed by agoraphobia (34.5%), obsessive-compulsive disorder (22.4%), PTSD (20.7%), and social phobia (20.7%). The results of this study provide important evidence that various anxiety/depressive disorders, in addition to PTSD, might follow after direct or indirect exposure to trauma. Our findings highlight the importance of comprehensive screening for psychiatric problems in children exposed to trauma of any scale.

Allergic rhinitis in laboratory animal workers and its risk factors

The workers in an animal laboratory are exposed to laboratory animal allergens (LAAs). To evaluate the difference of sensitization to LAAs and the symptoms according to the exposure levels and to investigate the risk factors for sensitization to LAAs. The subjects were divided into 3 groups according to the presence or absence of exposure: 74 subjects were in the direct exposure group, 33 subjects were in the indirect exposure group, and 30 subjects were in the control group. Each group answered the questionnaire and underwent skin prick tests that included 10 common allergens and 10 LAAs. The levels of total IgE and specific IgE to mouse and rat urine allergen were measured by enzyme-linked immunosorbent assay in 2 exposure groups. Allergic symptoms, skin sensitization, and serum IgE level were compared between the study groups. Twenty-five (34%) of the 74 subjects in the direct exposure group experienced allergic symptoms since their exposure to laboratory animals. The subjects in the direct and indirect exposure groups had more sensitization to LAAs than did the control subjects. The direct exposure group had more positive results for total IgE than did the indirect exposure group. The subjects in the direct exposure group with atopy had more severe allergic symptoms than the subjects in the indirect exposure group with atopy. Atopy and total IgE level were risk factors for the sensitization to LAAs for the direct exposure group (odds ratios, 7.47 and 7.33, respectively). Indirect exposure may be as risky for sensitization to LAAs as direct exposure. More careful protection is needed for laboratory animal workers with atopy.

Paraquat Poisoning of the Lung: HRCT Findings According to the Amount of Ingestion

Purpose: This study was designed to investigate the pattern, distribution and extent of pulmonary abnormalities in relation to the amount of ingested paraquat as determined with the use of high resolution computed tomography (HRCT). Materials and Methods: The study included 15 patients exposed to paraquat based on a positive urine assay and the presence of pulmonary abnormalities as detected on HRCT scans. The pattern, distribution and extent of pulmonary abnormalities in relation to the amount of ingested paraquat was evaluated. Patients were classified into five groups based on the amount of paraquat that was ingested. The groups were designated as indirect exposure, minimum exposure (the patient spat out the agent after swallowing), low exposure ( 30 cc), medium exposure (31-60 cc) and high exposure (61-100 cc). Results: Abnormal lung parenchymal patterns as depicted on HRCT images consisted of ground glass opacity (n = 9), consolidation (n = 9), irregular lines (n = 9) and the presence of nodules (n = 2). The most common distribution was in the lower and subpleural lung zone with no relation to the amount of ingestion. The most common patterns were the presence of irregular lines in the indirect exposure group and ground glass opacity in the high exposure group. The mean number of involved lobes increased in relation to the amount of ingestion. Conclusion: For paraquat poisoning, the pattern and extent of pulmonary abnormalities were related to the amount of ingestion, but the distribution of pulmonary abnormalities was not related to the amount of ingestion.

Study on the oxidative stress status among cement plant workers

The cement industry is considered as a major pollution problem because of dust and particulate matter emitted at various steps of cement production. In the present study, volunteer male workers from a cement factory were studied for oxidative and nitrosative stress biomarkers in relation to their serum levels of aluminum (Al) and chromium (Cr). The subjects were divided into two groups of direct and indirect exposure. Subject who worked in production steps were considered as direct exposure group, and those who worked in administration building were considered as indirect exposure group. For comparison, healthy subjects at the same age and socioeconomic status were tested as a control group. Serum levels of lipid peroxidation (LP), total antioxidant capacity (TAC), total thiol molecules (TTM), and nitric oxide (NO) as well as Al and Cr were measured. The results indicated a significant increase in Al (P = 0.001) and Cr (P = 0.009) levels in direct-exposed workers in comparison to healthy control group. Further, a significant increase in Al (P = 0.002) and Cr (P = 0.009) levels was observed in direct-exposed workers as compared to indirect-exposed one. Serum levels of TTM and TAC were significantly lower in both direct- and indirect-exposed groups in comparison to healthy control group (P = 0.00). Serum TTM and TAC were significantly lower in direct-exposed workers as compared to indirect-exposed ones (P = 0.00 and P = 0.024, respectively). There was no significant difference on the level of LP and NO among groups. A correlation was found between serum level of Cr, TAC, and platelets between direct- and indirect-exposed groups (P < 0.05). Further correlation was found among serum level of Cr and those of TTM, platelets, and chronic disease (P < 0.05). Chronic disease had a significant influence adjusted to other predictor variables on the post-shift values of Al (P < 0.05). Although plasma levels of Al and Cr were found in normal ranges, analyses confirm their role in impairment of TMM and TAC.

The Effects of Indirect Exposure to September 11th–Related Trauma on Cardiovascular Reactivity

Direct and indirect exposure to trauma is related to cardiovascular reactivity to stress, which is a marker for the future development of cardiovascular disease. The current study compared the effects of indirect exposure and no exposure (assessed via self-reports) to the 9/11 terrorist attacks on cardiovascular reactivity among a sample of 31 New Yorkers. Cardiovascular responses, measured every 2 minutes during baseline, a semistructured interview in which they relived a personally relevant aspect of the terrorist attack, and recovery periods revealed that the indirect exposure group had significantly higher diastolic blood pressure levels at baseline (p < .01), task (p < .05), and recovery (p < .05) than the no exposure group. No differences in trauma symptoms were observed between the two groups. Results suggest that indirect exposure to a traumatic event may have an impact on physiological responses to stress.

Describing Traumatic Responses and Distress of Community Residents Directly and Indirectly Exposed to an Aircraft Crash

This study described the traumatic responses and the extent of psychological distress among residents who had been exposed directly or indirectly to an aircraft crash in Coventry, U.K. The direct exposure group consisted of 62 residents who were on the housing estate at the time of the accident and 20 who were not. They were interviewed on their subjective responses to the crash and then asked to fill in two distress measures: the Impact of Event Scale (IES) and the General Health Questionnaire (GHQ). The results showed a contrast between the responses of the two groups at the time of the crash. They also showed that the direct exposure group had a significantly higher score in the IES item of avoidance, the IES total, the GHQ items of somatization, social dysfunction, and the total score than the indirect exposure group had. Associations were then made between subjective responses and distress measures. Stepwise multiple regression analyses showed that for the direct exposure residents, the IES total was predicted by "whether they received professional help" and "whether they were worried about their safety after the crash." The GHQ total of the direct exposure residents was predicted by "anger about what had happened to them." For the indirect exposure residents, the IES total was predicted by "their present feelings when they heard planes flying over." There were no predictions found between responses and the GHQ total.