Spectrum of health condition in methyl isocyanate (MIC)-exposed survivors measured after 30 years of disaster

Association between volatile organic compounds exposure and infertility risk among American women aged 18-45 years from NHANES 2013-2020

The risk of infertility is progressively escalating over the years, and it has been established that exposure to environmental pollutants is closely linked to infertility. As a prevalent environmental pollutant in daily life, there is still a lack of substantial evidence on the association between volatile organic compounds (VOCs) exposure and infertility risk. This study aimed to examine the association between VOCs exposure and the risk of female infertility in the United States. Participant data sets from three cycles (2013-2020) were collected and downloaded from the National Health and Nutrition Examination Survey (NHANES), including demographics, examination, laboratory and questionnaire data. The baseline characteristics of the included population were evaluated, and the weighted quartile logistic regression was used to analyze the association between the urinary metabolites of VOCs (mVOCs) levels and the risk of infertility. Further exploration of the relationship between mVOCs and infertility was conducted by using 35 and 25 as the cut-off points for age and BMI subgroup analyses, respectively. Restricted cubic spline (RCS) was employed to elucidate the nonlinear relationship between mVOCs and infertility risk. Additionally, the Bayesian kernel machine regression (BKMR) model with 20,000 iterations was applied to elucidate the link between mVOCs and the risk of infertility when exposed to mixed or individual mVOCs. A total of 1082 women aged 18 to 45 years were included in this study, with 133 in the infertility group and 949 in the control group. The analysis of baseline characteristics suggested that urinary 34MHA, AMCC and DHBMA levels were significantly higher in the infertility group compared to the control group (p < 0.05). Quartile logistic regression analysis indicated that AAMA (Q3), AMCC (Q4), CYMA (Q3) and HPMMA (Q3) were positively associated with infertility risk in all models (p < 0.05). Subgroup analysis revealed different risk factors for infertility among various subgroups, with CYMA consistently showing a positive correlation with infertility risk in two age subgroups (p < 0.05). Furthermore, the association between mVOCs and infertility was observed only in the subgroup with BMI ≥ 25 kg/m2. RCS analysis indicated that 2MHA, ATCA, BMA, BPMA, CYMA, 2HPMA, 3HPMA and PGA exhibited linear dose-response relationships with infertility (p > 0.05), while the remaining variables showed nonlinear relationships (p < 0.05). The BKMR model demonstrated that the risk of female infertility exhibited an increasing trend with the accumulation of mVOCs co-exposure. A positive association between the exposure to mVOCs represented by 34MHA and AMCC and the risk of infertility was observed in this research. However, the inherent limitations associated with the cross-sectional study design necessitate the pursuit of additional prospective and experimental research to further elucidate and validate the relationships between various mVOCs exposure and female infertility.

MIC accident: lesson may guide for evaluation of genotoxic potential of the industrial chemicals for prevention of industrial accidents

Most of the individual and/or amalgamated compounds present in the atmospheric air are not known for their toxicologic potential and impact on human health. The toxicologic strength of methyl isocyanate (MIC) gas was unknown till its accidental leakage that instantly claimed thousands of lives. Cytogenetic study showed increased chromosome aberrations (CA) and sister chromatid exchanges (SCEs) and delayed cell replication index (RI) in a multicentre genetic screening program on gas victims immediate post-disaster. A surveillance study after 30 years displayed reduction in CA compared to the initial status in survivors of the severely and moderately exposed strata. Altogether, cytogenetic damage was significantly predominant in the severely exposed population. Stable and replicable aberrations and chromatid exchanges were detected in both studies, which collectively indicate genetic instability. The variation in individual cytogenetic spectrum from similar exposure status could be the result of inter-individual response to the external factors over 30 years post-disaster. The spectrum of CA detected after 30 years might be the cumulative effect of occupational, environmental and life-style factors at a background of one episode of acute MIC exposure. Had MIC's toxicologic potential was known before, fatality and health effects could have been averted. In vitro assessment of toxicity of tin showed a positive correlation with dose and age of exposure, which was aggravated by smoking. Age has shown a significant effect on CA in the general population. The present report recommends evaluation of toxicity prior to use, and reduction of pollution at source for a maintaining a sustainable environmental context.

Contaminants of emerging concern in urine: a review of analytical methods for determining diisocyanates, benzotriazoles, benzothiazoles, 4-methylbenzylidene camphor, isothiazolinones, fragrances, and non-phthalate plasticizers

Human biomonitoring (HBM) frameworks assess human exposure to hazardous chemicals. In this review, we discuss and summarize sample preparation procedures and analytical methodology for six groups of chemicals of emerging concern (CECs), namely diisocyanates, benzotriazoles, benzothiazoles, 4-methylbenzylidene camphor, isothiazolinones, fragrances, and non-phthalate plasticizers, which are increasingly detected in urine, however, are not yet widely included in HBM schemes, despite posing a risk to human health. The sample preparation procedures depend largely on the chemical group; however, solid-phase extraction (SPE) is most often used due to the minimized sample handling, lower sample volume, and generally achieving lower limits of quantification (LOQs) compared to other extraction techniques. In terms of sample analysis, LC-based methods generally achieve lower limits of quantification (LOQs) compared to GC-based methods for the selected six groups of chemicals owing to their broader chemical coverage. In conclusion, since these chemicals are expected to be more frequently included in future HBM studies, it becomes evident that there is a pressing need for rigorous quality assurance programs to ensure better comparability of data. These programs should include the reporting of measurement uncertainty and facilitate inter-laboratory comparisons among the reporting laboratories. In addition, high-resolution mass spectrometry should be more commonly employed to enhance the specificity and selectivity of the applied analytical methodology since it is underrepresented in HBM. Furthermore, due to the scarcity of data on the levels of these CECs in urine, large population HBM studies are necessary to gain a deeper understanding of the associated risks.

Evaluation of Cytogenetic Alterations in Patients of Chronic Kidney Disease

Introduction

In recent years, there has been a rise in chronic kidney disease (CKD), and it has been estimated that by 2040, CKD will be the fifth most common cause of death globally. In addition to diabetes, hypertension, obesity, hyperlipidemia, and nonalcoholic fatty liver disease commonly associated with CKD, exposure to various toxins as a result of pollution or industrial disasters is also discussed as a cause for multi-organ pathology including kidneys. Although few cytogenetic studies were undertaken to assess the genetic damage in survivors of the disaster, no studies are available on the cytogenetic damage of toxic-gas exposed population having CKD. Therefore, the present multi-group cross-sectional study was undertaken to assess the independent role of CKD as well as toxic gas exposure on cytogenetics.

Methods

The cytogenetic alterations were evaluated through chromosomal aberration analysis and micronuclei assay. The study included 608 study participants divided into four groups on the basis of history of exposure to the leaked gas and presence or absence of CKD.

Results

The results of the study showed no statistically significant difference in cytogenetic damage between gas-exposed and non-exposed patients of CKD, whereas significantly higher cytogenetic damage was observed among gas-exposed participants having CKD compared to gas-exposed participants free from CKD, suggesting that cytogenetic changes could be due to CKD itself.

Conclusions

Thus, to conclude, the cytogenetic alterations observed in the study can be partly attributed to the disease itself.

Long-term health and human capital effects of in utero exposure to an industrial disaster: a spatial difference-in-differences analysis of the Bhopal gas tragedy

OBJECTIVES

Globalisation and industrialisation can increase economic opportunity for low/middle-income nations, but these processes may also increase industrial accidents and harm workers. This paper examines the long-term, cohort-based health effects of the Bhopal gas disaster (BGD), one of the most serious industrial accidents in history.

DESIGN

This retrospective analysis uses geolocated data on health and education from India's National Family Health Survey-4 (NFHS-4) and the 1999 Indian Socio-Economic Survey by the National Sample Survey Organization (NSSO-1999) to examine the health effects of exposure to the BGD among men and women aged 15-49 years living in Madhya Pradesh in 2015-2016 (women n=40 786; men n=7031 (NFHS-4) and n=13 369 (NSSO-1999)), as well as their children (n=1260). A spatial difference-in-differences strategy estimated the relative effect of being in utero near Bhopal relative to other cohorts and to those further from Bhopal separately for each dataset.

RESULTS

We document long-term, intergenerational impacts of the BGD, showing that men who were in utero at the time were more likely to have a disability that affected their employment 15 years later, and had higher rates of cancer and lower educational attainment over 30 years later. Changes in the sex ratio among children born in 1985 suggest an effect of the BGD up to 100 km from the accident.

CONCLUSIONS

These results indicate social costs stemming from the BGD that extend far beyond the mortality and morbidity experienced in the immediate aftermath. Quantifying these multigenerational impacts is important for policy consideration. Moreover, our results suggest that the BGD affected people across a substantially more widespread area than has previously been demonstrated.

Spectrum of stable and unstable rearrangements in lymphocytic chromosomes investigated in Bhopal population 30 years post MIC disaster amid co-exposure to lifestyle, living, and occupational hazards

Immediate assessment of genetic damage in methyl isocyanate (MIC) gas-exposed population in small and heterogeneous samples using diversified study designs and solid-stained metaphases could not depict the actual genetic impact of MIC on accidentally exposed individuals. The outcome of the then large multi-center genetic screening program was not available to the public and scientific community. Also, the routine and regular epidemiological health survey does not capture the genetic and long-term effect of MIC. Therefore, genetic screening was carried out 30 years post disaster during 2015-2017 with a view to screen the present status of chromosomal consequences in lymphocytic cells. Participants were recruited from moderate (34) and severely (78) exposed and unexposed (35) cohorts with their informed consent. Analysis of ~100 mitotic cells and karyotyping of at least 10-15 and all abnormal metaphases detected structural and numerical alterations, including stable and replicable ones. Clonal abnormalities were detected with monosomal and complex karyotypes, trisomy 8, del5q/20q, loss of Y, etc. Among all, X-chromosome was frequently involved in numerical alterations. Structural aberrations appeared higher in the then exposed populations, though abnormalities cannot be linked directly to MIC exposure 30 years post disaster. Collectively, all rearrangements were markedly higher in the severely exposed population. Altogether, the detected abnormalities appeared random and indicated genomic instability, suggesting follow-up at shorter intervals for the individuals detected with clonal aberrations. G-banding has facilitated recognition of chromosomal involvement and their breakpoints and classification of structural rearrangements. The present data has been derived from the 30-year post-disaster genetic screening.

Exposure index of methyl isocyanate (MIC) gas disaster and a comprehensive spectrum of cytogenetic analysis after 30 years

Severity of clinical expression and high mortality could not facilitate establishing exposure index/association following MIC disaster in Bhopal. Mortality-based exposure stratification was critiqued by the International Medical Commission on Bhopal (IMCB). IMCB stratified exposure considering distance as surrogate at 2 km intervals after 10 years. The first follow-up cytogenetic screening of the pre-screened survivors after 30 years has demonstrated chromosome abnormalities (CA). Exposure stratification was attempted considering cytogenetic screening conducted during 1986-1988. Elevation of CA appeared proportional to exposure status and authenticated the initial mortality-based stratification. The one-on-one comparison of the previous and present cytogenetics has described the individual response to MIC exposure over 30 years. Chi-square test has been carried out for checking the cytogenetic changes at the individual level statistically, which revealed that differences of chromosomal aberrations collected immediately post-disaster and 30 years later are nonsignificant. The prominence of interindividual variation was noticed in general. The impact of overall exposure was higher in males. Constitutional abnormalities in 8.5% of the study population, including translocation, inversion, deletion, fragile sites, etc., necessitate screening of blood-linked members. The incidence of acrocentric association was prominent in the study population. Normal karyotype in children born to severely exposed parents with congenital anomalies indicates necessity of molecular karyotyping and/or screening of mutations. The study highlights follow-up of the health of the index cases at shorter (3-6 months) intervals. This comprehensive spectrum of cytogenetic report highlights immediate post-disaster chromosomal aberrations, the changes that occurred over 30 years in conjunction with other environmental factors at the individual level, constitutive genomic aberrations, polymorphic variations, and chromosomal patterns in congenitally malformed children of the survivors, which collectively indicate the possibility of acquisition/persistence of stable aberrations in MIC-exposed lymphocytes through interaction with environmental/biological confounders.

Effect of age at exposure on chromosome abnormalities in MIC-exposed Bhopal population detected 30 years post-disaster

Follow-up cytogenetic study was carried out on 145 individuals from areas stratified by Indian Council of Medical Research, for evaluation of the effect of age-at-exposure and its interaction with exposure status on chromosomal aberrations (CA) in blood-lymphocytes. CA was presented as abnormal cell (Abc), aberrations (Abn) and number of aberration/abnormal cell (Abn/Abc), and correlated with age-at-exposure (childhood: <1-10 years; young: 11-26 years; adult: >27 years). Age related increase in abnormalities (Abc, Abn, Abn/Abc) was observed in all exposure strata, except moderately exposed adult-group, which has exhibited lower Abn/Abc than similarly exposed childhood and young age-groups. Elevation of CA was also related to exposure status. Abn/Abc frequency was significantly higher in the severely exposed young and adult groups compared to the controls of the same age. Two-way ANOVA revealed significant abnormalities between the exposed groups; however, interaction of age and exposure was not statistically significant. Significant difference in group-means of Abc and Abn was also observed between adult and childhood in Tukey HSD test. Altogether, a significant interaction of age and MIC-exposure on CA could not be established due to inter-individual variation and lack of baseline information on CA. Significantly higher Abn was observed in people consuming tobacco; however, interaction of lifestyle with additional environmental/occupational exposures during last 30 years against a background exposure to MIC remained un-elucidated. Nevertheless, the study was important for demonstration of the correlation of the current status of CA in circulating lymphocytes with age and exposure status of the MIC-exposed survivors.