Epidemiological Case-control Study Research Articles

Nickel and tattoos: Where are we?

Tattoos are not mentioned as a source of exposure to nickel. Traces of nickel are, however, almost inevitably found in tattoo inks as impurities and sometimes in tattooed skin. Whether nickel in tattoos has any health consequence is debated. We performed a narrative review of what is currently known about this topic. Today, nickel is frequently detected in inks, but at highly variable levels. It appears to be at higher concentrations in green, blue, and sometimes brown and violet inks. Only nickel allergy in tattooed individuals and nickel-associated tattoo ink allergy are addressed in the literature. Reports of tattoo ink allergy related to nickel are rare and heterogenous. Authors often neglect possible implications of other metals or dyes. A positive patch test is not enough to confirm the role of nickel in a reaction observed after tattooing. We found no report of any systemic complication attributed to nickel from tattoos. The Council of Europe ResAP(2008)1 bans the presence of nickel at high levels in tattoo inks, which is a safety net for individuals with nickel allergy. Large epidemiologic case-control studies with systematic biopsies on normal and inflamed tattoos and patch testing would help to understand the role of nickel in tattoo ink allergies.

Risk Factors for Alzheimer’s Disease: An Epidemiological Study

Dementia becomes a major public health challenge in both the Czech Republic and worldwide. The most common form of dementia is Alzheimer's disease (AD). We conducted two successive epidemiological projects in 2012-2015 and 2016-2019. Their aim was to study the effect of selected potential genetic, vascular and psychosocial risk factors on the development of AD by comparing their frequencies in AD patients and controls. Epidemiological case-control studies were conducted. In total, data from 2106 participants (1096 cases, 1010 controls) were analyzed. Three times more females than males suffered from AD. The highest proportion of cases were those with primary education, unlike controls. There were statistically significantly more manual workers among cases than among controls. Of selected vascular risk factors, coronary heart disease was found to be statistically significantly more frequent in cases than in controls. The onset of hypertension and diabetes mellitus was earlier in controls than in cases. As for hobbies and interests, there were statistically significant differences in physical activity, reading and solving crosswords between the groups, with these activities being more common in controls. The prevalence of chronic neurodegenerative diseases, in particular AD, is currently increasing. Given the aging of the population, these conditions may be expected to rise in prevalence. Potential risk of AD needs to be studied, analyzed and confirmed; a detailed knowledge of the risks of AD and early detection of the pathology may therefore be very beneficial for prevention and early treatment of this condition.

Recruitment of population-based controls for ALS cases from the National ALS Registry

Objective: In 2010, the United States Agency for Toxic Substances and Disease Registry (ATSDR) created the National ALS Registry (Registry) to examine the epidemiology of ALS and potential risk factors. We are currently recruiting population-based controls for an epidemiologic case-control study to examine ALS environmental risk factors using this Registry. To date, we have recruited 181 non-diseased, population-based controls for comparison to Registry cases (n = 280). Here we report our recruitment methods for controls and the associated response rates and costs. Methods: Eligible ALS cases had complete risk factor survey data, DNA analysis, and blood concentrations of persistent organic pollutants (POPs). Age, sex, and county-matched controls were identified from commercial/consumer databases using a targeted landline phone sample. Eligible controls were consented, surveyed, and mailed the POPs’ blood analysis consent form. Once consented, phlebotomy was scheduled. Results: We mailed 3760 recruitment letters for 181 potential case-matches across 42 states between 9/2018 and 3/2020. After making phone contact and determining eligibility, 146 controls agreed to participate (response rate = 11.4%, cooperation rate = 22.8%). To date, 127 controls completed the survey and bloodwork. Though controls were matched to cases on age, sex, and county, unmatched characteristics (e.g. smoking) did not differ statistically. Interviewing and incentive costs are estimated at $211.85 per complete participation. Conclusions: Recruiting matched population-based controls for comparison to cases from the Registry for a study involving completion of a detailed survey and blood specimen provision is relatively feasible and cost effective. This recruitment method could be useful for case-control studies of other rare disorders.

Risk factors and comorbidities associated with severe aortic stenosis: A case-control study

Background and objectiveAortic stricture (AS) is one of the most prevalent cardiovascular diseases in individuals 65 years of age or older. A number of epidemiological studies have suggested that certain cardiovascular risk factors (CRFs) and comorbidities could be associated with AS. The aim of this study was to evaluate the association between CRFs and comorbidities and severe symptomatic AS in individuals 65 years of age or older in a Spanish healthcare region. Patients and methodsWe conducted an epidemiological case-control study from a single primary care centre. We collected information on exposure to CRFs and comorbidities and determined their association with AS, employing adjusted odds ratios (OR) and multiple logistic regression models. ResultsThe study included 102 cases (mean age, 77.6 years) and 221 controls (mean age, 75.5 years). The CRFs significantly associated with severe symptomatic AS were hypercholesterolaemia (OR, 2.67; p < .001), tobacco use (OR, 2.60; p < .001), hypertension (OR, 2.41; p = .010) and low HDL cholesterol readings (OR, 2.20; p = .007). The comorbidities significantly associated with severe symptomatic AS were carotid stenosis (OR, 14.5; p = .017), stroke (OR, 4.14; p = .024), chronic renal failure (OR, 3.78; p < .001) and low haemoglobin levels (OR, 0.76; p < .001). ConclusionsHypercholesterolaemia, tobacco use, arterial hypertension and low HDL cholesterol levels are the CRFs with a greater risk of severe AS. Furthermore, this disease is associated with a number of comorbidities (chronic renal failure, stroke, carotid stenosis and low haemoglobin levels), which could be markers of AS.

An altered global DNA methylation status in women with depression

Sparse studies have shown that specific biomarkers of a global DNA methylation status may be related to various mental diseases and states, including: bipolar disorder (BD), anxiety and major depression disorder (MDD). The objective of this study was to analyze potential variation of the above mentioned global methylation status in women with depression. 38 women with a current and clinically confirmed depressive episode suffering from BD type I, type II or MDD and 71 women from the general population and at similar age were recruited for the study. Alu and LINE-1 methylation was assayed with the quantitative methylation-specific PCR technique with TaqMan probes, while the 5-mC and 5-hmC level was determined using the ELISA-based method. Significantly higher levels of 5-mC, Alu and LINE-1 methylation were observed in the women with depression as compared to the controls; while the 5-hmC level revealed to be significantly lower. The BD type I patients presented the highest level of 5-mC of all the women with a depressive episode. 5-mC level in the patients was positively and significantly correlated with the severity of the symptoms of depression. Relationships between Alu or LINE-1 methylation and 5-mC level were statistically significant only in the case of the control women. Alu and LINE-1 methylation do not constitute suitable biomarkers of global DNA methylation in the investigated patients. These findings require confirmation in case-control and prospective epidemiological studies.

Spatial and temporal variability of airborne ultrafine particles in the Greater Montreal area: Results of monitoring campaigns in two seasons

It has been hypothesized that ultrafine particles (UFP) in air pollution may cause lung cancer. In preparation for an epidemiologic case-control study to assess this hypothesis in Montreal, Canada, we conducted a UFP measurement campaign in order to create an exposure surface with which we could assign UFP exposure to subjects corresponding to their residential addresses. The purpose of this paper is to describe the temporal and spatial variability that underlies the creation of an exposure surface in the Montreal area, and to consider the implications for epidemiological exposure assessment.We identified 249 fixed sampling sites, selected to provide a dense spatial representation of the areas of residence of Montreal residents. We conducted a winter campaign and a summer campaign, and each of the sites was visited three times during each seasonal campaign. Each visit entailed a 20-minute measurement period for UFPs with a separate measurement each second. This provided data for temporal comparisons at each site between seasons, between visits and between seconds. The median of UFP measurements was 16,593 particles/cm3 in winter and 8919 particles/cm3 in summer. Across the 249 sampling sites the Spearman correlation coefficient between the UFP measurements of winter and summer was 0.35. Within each visit, correlation was below 0.50 between pairs of UFP measurements taken more than 60 s apart, and there was hardly any correlation among measurements taken more than 300 s apart. When sites were grouped by proximity to certain types of pollution sources, and the seven resulting groups compared, there were modest, albeit statistically significant, differences in UFP levels. There was moderate positive spatial autocorrelation in UFPs over the study area. High temporal variability of UFPs from short-term measurements campaigns will likely compromise the predictive validity of the exposure surface, and will eventually attenuate the epidemiologic risk estimates.

Estimation of pregnancy losses attributable to exposure to ambient fine particles in south Asia: an epidemiological case-control study

Maternal exposure to ambient particulate matter (PM2·5) is associated with pregnancy loss (ie, stillbirth and miscarriage). South Asia has the highest burden of pregnancy loss globally and is one of the most PM2·5 polluted regions in the world. However, knowledge of the relevant exposure-response function for mothers is insufficient. In this epidemiological case-control study, we collected data from Demographic and Health Surveys from India, Pakistan, and Bangladesh for the period 1998-2016 for women who reported at least one pregnancy loss and one or more livebirths. We assessed ambient exposure during gestation with satellite-based PM2·5 measurements for the period. To derive the exposure-response function, we did a self-compared case-control study in which each case of pregnancy loss was compared with a successful livebirth control or controls by the same mother. Using the estimated exposure-response function, we quantified pregnancy losses attributable to PM2·5 in the region for the period 2000-16 using a standard risk assessment approach. We assessed data for 34 197 mothers, who had at least one pregnancy loss and one or more livebirth, of whom 26 282 (76·9%) were from India, 4228 (12·4%) were from Pakistan, and 3687 (10·8%) were from Bangladesh. The 34 197 cases of pregnancy loss were matched with 76 282 livebirth controls. The mean level of PM2·5 exposure was 56·00 μg/m3 (SD 30·82) for cases and 54·57 μg/m3 (31·73) for controls. After adjustment for maternal age, non-linear terms for temperature and humidity, seasonal variation, and long-term trends, each 10 μg/m3 increment in PM2·5 was associated with an odds ratio for pregnancy loss of 1·03 (95% CI 1·02-1·05). According to the estimated non-linear exposure-response function by age and urban residence versus rural residence, for the period 2000-16, an estimated 349 681 (95% CI 152 932-489 493) pregnancy losses per year were attributed to ambient air exposure of more than 40 μg/m3 (the annual PM2·5 standard of India), accounting for 7·1% (95% CI 3·3-31·2) of the total annual pregnancy loss burden in south Asia for this period. However, our estimates could be biased because of the limitations of the data (eg, misclassification of induced and spontaneous pregnancy losses). Our findings add to epidemiological evidence of the association between pregnancy loss and PM2·5. Suboptimal air quality contributes to a considerable fraction of total pregnancy loss in south Asia. Controlling PM2·5 pollution will promote maternal health in south Asia. Chinese Natural Science Foundation and Ministry of Science and Technology of China.

The Effects of Cannabis Use on the Development of Adolescents and Young Adults

This review summarizes evidence on the effects of cannabis use on the development of adolescents and young adults. It draws on epidemiological studies, neuroimaging studies, case-control studies, and twin and Mendelian randomization studies. The acute risks include psychiatric symptoms associated with the use of high THC (tetrahydrocannabinol) products and motor vehicle accidents. Daily cannabis use during adolescence is associated with cannabis dependence and poor cognitive function, which may affect educational attainment and occupational choice. Daily use of highly potent cannabis is associated with more severe psychological symptoms, such as psychoses, mania, and suicidality. There are more mixed findings on depressive symptoms, anxiety, and violence and debates about the interpretation of these associations. Legalization of adult cannabis use may increase cannabis use and dependence among adolescents and young adults. The regulation of cannabis after legalization needs to minimize adolescent uptake and cannabis-related adverse developmental outcomes.

Аssessment of social risk factors of tuberculosis contamination in HIV-infected people according to epidemiological survey of epidemic foci

Objective. Assessment of tuberculosis (TB) infection conditions for HIV-infected people.Materials and methods. Еpidemiological survey of 38 epidemic foci of HIV-associated tuberculosis, 28 foci of tuberculosis without HIV infection and 20 foci in which the diagnosis of tuberculosis wasn`t confirmed (control-group) were conducted.Results and its discussion. As it turns out that in the most cases of the development of HIV-associated TB, the primary diagnosis of HIV infection preceded the primary diagnosis of tuberculosis. According to the results of the case-control analytical epidemiological study, such risk factors of HIV-infected tuberculosis as lack of family, higher education and regular job, the fact of deprivation of liberty and drug users (as a reflection of the low social status of patients), as well as contact with tuberculosis patient were identified. Risk factors for mycobacteria infection in people without HIV infection were only the lack of family and contact with tuberculosis patients.

Risk factors, comorbidities, quality of life, and complications after surgery in idiopathic normal pressure hydrocephalus: review of the INPH-CRasH study.

Idiopathic normal pressure hydrocephalus (INPH) is a dementia treatable by insertion of a shunt that drains CSF. The cause of the disease is unknown, but a vascular pathway has been suggested. The INPH-CRasH (Comorbidities and Risk Factors Associated with Hydrocephalus) study was a modern epidemiological case-control study designed to prospectively assess parameters regarding comorbidities and vascular risk factors (VRFs) for INPH, quality of life (QOL), and adverse events in patients with shunted INPH. The objective of this review was to summarize the findings of the INPH-CRasH study. VRFs, comorbidities, QOL, and adverse events were analyzed in consecutive patients with INPH who underwent shunt placement between 2008 and 2010 in 5 of 6 neurosurgical centers in Sweden. Patients (n = 176, within the age span of 60-85 years and not having dementia) were compared to population-based age- and gender-matched controls (n = 368, same inclusion criteria as for the patients with INPH). Assessed parameters were as follows: hypertension; diabetes; obesity; hyperlipidemia; psychosocial factors (stress and depression); smoking status; alcohol intake; physical activity; dietary pattern; cerebrovascular, cardiovascular, or peripheral vascular disease; epilepsy; abdominal pain; headache; and clinical parameters before and after surgery. Parameters were assessed through questionnaires, clinical examinations, measurements, ECG studies, and blood samples. Four VRFs were independently associated with INPH: hyperlipidemia, diabetes, obesity, and psychosocial factors. Physical inactivity and hypertension were also associated with INPH, although not independently from the other risk factors. The population attributable risk percent for a model containing all of the VRFs associated with INPH was 24%. Depression was overrepresented in patients with INPH treated with shunts compared to the controls (46% vs 13%, p < 0.001) and the main predictor for low QOL was a coexisting depression (p < 0.001). Shunting improved QOL on a long-term basis. Epilepsy, headache, and abdominal pain remained common for a mean follow-up time of 21 months in INPH patients who received shunts. The results of the INPH-CRasH study are consistent with a vascular pathophysiological component of INPH. In clinical care and research, a complete risk factor analysis as well as screening for depression and a measurement for QOL should probably be included in the workup of patients with INPH. The effect of targeted interventions against modifiable VRFs and antidepressant treatment in INPH patients should be evaluated. Seizures, headache, and abdominal pain should be inquired about at postoperative follow-up examinations.

METTL14 Gene Polymorphisms Confer Neuroblastoma Susceptibility: An Eight-Center Case-Control Study

Neuroblastoma is the primary cause of cancer death in childhood. METTL14 is tightly linked to cancer. However, whether single-nucleotide polymorphisms (SNPs) in the METTL14 gene could predispose to neuroblastoma susceptibility lacks evidence. With an epidemiology case-control study, associations between METTL14 gene SNPs and overall risk for neuroblastoma were estimated in 898 cases and 1,734 controls. Following that, stratified analysis was performed. Among the five analyzed SNPs, rs298982 G>A and rs62328061 A>G exhibited a significant association with decreased susceptibility to neuroblastoma, whereas the associations with increased neuroblastoma susceptibility were observed for rs9884978 G>A and rs4834698 T>C. Moreover, subjects carrying two to five risk genotypes were more inclined to develop neuroblastoma than those with zero to one risk genotypes. The stratified analysis further demonstrated the protective effect of rs298982 G>A and rs62328061 A>G, as well as the predisposing effect of rs4834698 T>C and two to five risk genotypes, in certain subgroups. Haplotype analysis was performed. Moreover, false-positive report probability analysis validated the reliability of the significant results. The expression quantitative trait locus analysis revealed that rs298982 is correlated with the expression levels of its surrounding genes. Our results suggest that some SNPs in the METTL14 gene are associated with predisposition to neuroblastoma.

Factores de riesgo y comorbilidades asociadas a la estenosis aórtica grave: estudio de casos y controles

Background and objectiveAortic stricture (AS) is one of the most prevalent cardiovascular diseases in individuals 65 years of age or older. A number of epidemiological studies have suggested that certain cardiovascular risk factors (CRFs) and comorbidities could be associated with AS. The aim of this study was to evaluate the association between CRFs and comorbidities and severe symptomatic AS in individuals 65 years of age or older in a Spanish healthcare region. Patients and methodsWe conducted an epidemiological case-control study from a single primary care centre. We collected information on exposure to CRFs and comorbidities and determined their association with AS, employing adjusted odds ratios (OR) and multiple logistic regression models. ResultsThe study included 102 cases (mean age, 77.6 years) and 221 controls (mean age, 75.5 years). The CRFs significantly associated with severe symptomatic AS were hypercholesterolaemia (OR, 2.67; p<.001), tobacco use (OR, 2.60; p<.001), hypertension (OR, 2.41; p=.010) and low HDL cholesterol readings (OR, 2.20; p=.007). The comorbidities significantly associated with severe symptomatic AS were carotid stenosis (OR, 14.5; p=.017), stroke (OR, 4.14; p=.024), chronic renal failure (OR, 3.78; p<.001) and low haemoglobin levels (OR, 0.76; p<.001). ConclusionsHypercholesterolaemia, tobacco use, arterial hypertension and low HDL cholesterol levels are the CRFs with a greater risk of severe AS. Furthermore, this disease is associated with a number of comorbidities (chronic renal failure, stroke, carotid stenosis and low haemoglobin levels), which could be markers of AS.

The Effect of In-Hospital Intervention to Reduce Door to Needle Time in Patients Receiving Tissue Plasminogen Activator

Background and Objective: Attempts have been made to confirm the diagnosis of stroke at the earliest stage and to prevent the development of neurological deficits. Tissue plasminogen activator (tPA) plays a logical role in the treatment of acute stroke by converting plasminogen to plasmin, and recent studies have shown that the drug can be injected up to four and a half hours after the onset of symptoms. The present study aimed to evaluate the effect of an in-hospital intervention to reduce door to needle (DTN) time in acute stroke patients. Methods: This epidemiological case-control study was performed on patients with acute ischemic stroke from September to March 2016 (n= 25) (group A) who were treated with tPA according to stroke guidelines. Their basic specifications, DTN and Door to Computed Tomography scan (DTC) time were recorded. Then, from April to August 2017, an intra-hospital recipe for tPA injection was provided by investigating the obstacles and causes of intra-hospital delays. Subsequently, stroke patients receiving tPA from September to March 2017 (n= 23) (group B) were examined, and their DTN and DTC were compared with patients in the first group. Results: The mean DTN and DTC in group A were 67.27±28.83 and 30.40±10.59 minutes, and in group B, were 45±25.98 and 22.17±8.50, minutes, respectively, which made a significant difference between the two groups (P=0.005, P=0.006, respectively). The percentage of patients with DTN less than 60 minutes increased from 52% in group A to 95.6% in group B. The percentage of patients with DTC less than 25 minutes decreased from 32% to 69.56% (P&lt;0.001). The percentage of patients with symptomatic cerebral haemorrhage increased from 12% to 8.7% (P&lt;0.001). The percentage of patients with independent ambulatory (mRS: 0-2) at three months after discharge increased from 48% to 56.5% (P=0.003). The mortality rate also decreased from 24% to 13.4% (P&lt;0.001). Conclusion: By resolving the causes of intra-hospital delays and using a proper team program, the mean DTN and DTC of patients receiving tPA were reduced. This decrease in DTN time was accompanied by reduced complications in the form of reduced symptomatic cerebral haemorrhage and mortality and improved prognosis.

Spatial and temporal patterns of Lyme Neuroborreliosis on Funen, Denmark from 1995\u20132014

In Europe, Lyme neuroborreliosis (LNB) is the most severe manifestation of Lyme borreliosis and has recently been added to the communicable disease surveillance list for EU/EEA by the European Commission. In Northern Europe, LNB is primarily caused by the spirochete Borrelia garinii and transmitted by the tick Ixodes ricinus. This Danish observational epidemiologic case-control study includes every identified LNB patient (n = 401) on Funen, Denmark, from 1995-2014. We display spatial and temporal LNB incidence variation, seasonal distribution of cases and local spatial case clustering. Seasonal patterns show LNB symptom-onset peaking in July and a significant seasonal difference in number of cases (p < 0.01). We found no significant change in seasonality patterns over time when dividing the study period into 5-year intervals. We identified a significant local geographical hot-spot of cases with a relative risk of 2.44 (p = 0.013). Analysis revealed a significantly shorter distance to nearest forest for cases compared with controls (p < 0.001). We present a novel map of the focal geographical distribution of LNB cases in a high endemic borreliosis area. Continued studies of case clustering in the epidemiology of LNB are of key importance in guiding intervention strategies.

Threatening Life Events and Difficulties and Psychotic Disorder.

ObjectiveStressful life events have been implicated in the onset of psychotic disorders, but there are few robust studies. We sought to examine the nature and magnitude of associations between adult life events and difficulties and first-episode psychoses, particularly focusing on contextual characteristics, including threat, intrusiveness, and independence. MethodThis study forms part of the Childhood Adversity and Psychosis Study (CAPsy), an epidemiological case-control study in London, United Kingdom. Data on life events and difficulties (problems lasting 4 wk or more) during 1 year prior to onset (cases) or interview (controls) were assessed using the semi-structured Life Events and Difficulties Schedule (LEDS). Data were available on 253 individuals with a first episode of psychosis and 301 population-based controls. ResultsWe found strong evidence that odds of exposure to threatening and intrusive events in the 1 year prior to onset were substantially higher among cases compared with controls, independent of age, gender, ethnicity, and social class (ORs > 3). This was consistent across diagnostic categories. We found further evidence that the effect of threatening events and difficulties was cumulative (1 event odds ratio [OR] 2.69 [95% confidence interval (CI) 1.51–4.79]; 2 events OR 4.87 [95% CI 2.34–10.16]; ≥3 events OR 5.27 [95% CI 1.83–15.19]; 1 difficulty OR 3.02 [95% CI 1.79–5.09]; 2 difficulties OR 9.71 [95% CI 4.20–22.40]; ≥3 difficulties OR 12.84 [95% CI 3.18–51.85]). ConclusionsThreatening and intrusive life events and difficulties are common in the year pre-onset among individuals with a first episode of psychosis. Such experiences may contribute to the development of psychotic disorders.

Radon exposure and lung cancer: analysis of risk for residents of Rivne City (Ukraine)

The comparison of complex epidemiological (cohort, case-control and ecological) studies of Radon influence on incidence of lung cancer among mining populations of world mines and residents of the city of Rivne was conducted. The calculation of additional relative risk for the residents of the city of Rivne by the method of epidemiological ecological studies performed on radiometric equipment AlfaRad+and calculated according to the BEIR VI risk model in two variants: exposure-age-duration (EAD) and exposure -age-concentration (EAC) was conducted. The values of the risk coefficients of the dependencies of the relative risk on Radon exposure we obtained for residents of Rivne are lower than the ones obtained for miners (according to literature) – 0.31 (EAD) and 0.49 (EAC) per 100 WLM for volumetric activity (VA) of Radon in housing 200 Bq/m3 and 1420 Bq/m3. The thesis about the impossibility of automatically applying the obtained dependencies of additional relative risk of lung cancer on exposure to Radon for miners to the general population according to the variants of risk models proposed in BEIR VI was verified.

Magnesium/silicon atomic weight percent ratio standards for the tissue identification of talc by scanning electron microscopy and energy dispersive X-ray analysis

ABSTRACTTalc may lodge in human tissues through various routes, and has been associated with the development of ovarian carcinoma in case control epidemiologic studies. Talc is detected in tissues with scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDS), with expected magnesium (Mg) and silicon (Si) peaks. The theoretical atomic weight % Mg/Si ratio for talc is 0.649, and for diagnostic purposes, a range of ± 5% (~0.617 to 0.681) is often used as a standard. Our goal was to establish empirically the quantitative range for talc identification by SEM/EDS using two source materials: a Johnson’s Baby PowderTM (cosmetic-grade) consumer sample, and talc from Sigma-Aldrich (particle-grade material intended for scientific use). We examined 401 Mg-Si particles with SEM/EDS across the two samples, using two different SEM microscopes. Overall, we found a mean Mg/Si atomic weight % ratio of 0.645, with minimal differences between study subsets. The standard deviation was 0.025; (± 1σ = 0.620–0.670). The currently used ± 5% diagnostic range (Mg/Si 0.617–0.681) is thus reasonably close to this study’s ± 1σ range, and well within a ± 2 σ confidence interval span (Mg/Si 0.595–0.695). The ± 5% range is thus an appropriately conservative standard whose continued use seems justified.

Is High Altitude an Emergent Occupational Hazard for Primary Malignant Brain Tumors in Young Adults? A Hypothesis

Abstract Introduction: Brain cancer accounts for approximately 1.4% of all cancers and 2.3% of all cancer-related deaths. Although relatively rare, the associated morbidity and mortality affecting young- and middle-aged individuals has a major bearing on the death-adjusted life years compared to other malignancies. Over the years, we have observed an increase in the incidence of primary malignant brain tumors (PMBTs) in young adults. This observational analysis is to study the prevalence and pattern of brain tumors in young population and find out any occupational correlation. Materials and Methods: The data were obtained from our tertiary care cancer institute's malignant diseases treatment center registry from January 2008 to January 2018. A total of 416 cases of PMBT were included in this study. Results: Our analysis suggested an overall male predominance with most PMBTs occurring at ages of 20–49 years. The glial tumors constituted 94.3% while other histology identified were gliosarcoma (1) gliomatosis cerebri (1), hemangiopericytoma (3), and pineal tumors (3). In our institute, PMBT constituted 1% of all cancers while 2/416 patients had secondary glioblastoma multiforme with 40% showing positivity for O-6-methylguanine-DNA-methyltransferase promoter methylation. Conclusions: Most patients belonged to a very young age group without any significant family history. A probable hypothesis could be excessive cosmic radiation exposure to persons staying at high altitude areas due to occupational exigencies for which in-depth case–control epidemiological studies are required to reach any conclusion.

Infection related to Klebsiella pneumoniae producing carbapenemase in renal transplant patients.

To evaluate the risk factors related to Klebsiella pneumoniae carbapenemase infection after renal transplantation. This was a retrospective epidemiological (case-control) study, conducted from October 2011 to march 2016. Transplanted patients with infection by this bacteria during hospitalization were selected as cases. The controls were paired by age, sex, type of donor and transplant time. The proportion of cases and controls was 1:2. Thirty hundred and five patients were included in the study (45 cases and 90 controls). The risk factors found for infection by KPC were: time of hospitalization after the transplant (OR: 4.82; CI95% 2.46-9.44), delayed kidney function (OR: 5.60; CI95% 1.91-11.01) and previous infectious for another microorganism ( OR: 34.13 CI95% 3.52-132.00). The risk of acquisition of this bacterium was directly related to invasive procedures and exposure to the hospital environment. The findings reinforce the importance of prevention measures and control of infection by this microorganism.

Effect of Radiation Exposures on Fetal Hematopoietic Cells

It has generally been thought that fetuses are highly sensitive to radiation-induced cancer. Epidemiologic case-control studies indicated that X-ray exposures given to pregnant women (on the order of 1 cGy) could have increased the risk of developing childhood leukemia and solid cancers in the offspring. The authors wished to re-consider this observation. Atomic bomb survivors who were exposed in utero were found to show almost no increase in the frequency of translocations in their blood lymphocytes when the survivors were examined at around 40 years of age. Subsequent animal studies revealed that tissue stem cells in embryos/fetuses may or may not retain radiation-induced chromosome damage depending on the developmental stage at the time of irradiation. Our data are compatible with the model that radiation effects can be recorded only when an exposure occurs after the stem cells have settled in their appropriate niche, and that a small fraction of fetal hematopoietic stem cells began making long-term contributions to the lymphoid cell pool in both mice and humans. It remains to be established whether or not the increased risk of childhood leukemia and other childhood cancers was caused by fetal X-ray exposures of about 1 cGy.