Chromium status of tannery workers in relation to metabolic disorders

Cr (III) genotoxicity and oxidative stress: An occupational health risk for leather tannery workers of South Asian developing countries

In the leather industry, Cr (III) is used as a basic tanning agent. The wastewater discharged from the tannery industry contains a high concentration of chromium. Recent studies indicate the genotoxic effects especially DNA damage and oxidative stress of Cr (III) in tannery workers. Cr (III) interacts with DNA to form DNA cross-links and DNA strand breaks. It also modifies the oxidative DNA base through the Haber–Weiss reaction. The present study is based on an overview of scientific literature and previous observations regarding the effects of tannery chromium effluents on exposed workers and the population in the vicinity. This study strongly suggests for use of a non-toxic substitute of chromium to be used for the tanning process and placement of tannery industries on the outskirts of the city. In South Asian developing countries like India, Pakistan and Bangladesh where the economy is strongly dependent on leather manufacturing industries, there is a need to spread proper information regarding the harmful effects of chromium toxicity to the workforce employed in the tannery and also to the people living in the surrounding area. Workers should be provided with the required safety protections like gloves, aprons, foot/shoe covers, masks, etc. Last but most important on an immediate basis is the installation of the proper efficient waste treatment plant, so that, waste should be treated before moving out of the industry.

Negatively interactive effect of chromium and cadmium on obesity: Evidence from adults living near ferrochromium factory

BACKGROUND

Researchers have reported that chromium (Cr) exposure may be associated with metabolism of glucose and lipids in residents living in a long-term Cr polluted area. Previous statistical analysis is mainly focused on individual chromium exposure. Furtherly, we aim to investigated the independent, combined, and interaction effects of the co-exposure of urine Cr (UCr) with cadmium (UCd), lead (UPb) and manganese (UMn) on body mass index (BMI), waist circumference, and the risk of overweight and abdominal obesity.

METHOD

We enrolled 1187 participants from annual surveys between 2017 and 2019. Heavy metal concentrations in urine were standardized using covariate-adjusted urine creatinine levels. Multiple linear/logistic regression models were applied to measure the single effect of urine heavy metal concentration on the outcomes. The quantile-based g-computation (g-comp) model was used to evaluate the combined effect of metal mixture on the outcomes and to compare the contribution of each metal. Both additive and multiplicative interactions were measured for UCr with UCd, UPb, UMn on the outcomes. Analysis was performed on the overall population and stratified by smoking habit.

RESULTS

For the overall study population, UCr was positively associated with BMI (p trend = 0.023) and waist circumference (p trend = 0.018). For smoking participants, the g-comp model demonstrated that the metal mixture was negatively associated with BMI, with UCr and UCd contributing the most in the positive and negative direction. A negative additive interaction was observed between UCr and UCd on BMI and abdominal obesity. We did not observe a significant interaction effect of UCr with UPb or UMn.

CONCLUSION

Our study indicated that Cr and Cd exposure may be associated with BMI and waist circumference, with combined and interaction effects of the heavy metals noted. Further epidemiological and experimental researches could simultaneously consider single and complex mixed exposure to verify the findings and biological mechanisms.

Chromium-mediated hyperpigmentation of skin in male tannery workers in Bangladesh

Since tannery workers in developing countries are chronically exposed to high levels of chromium (Cr), there are serious concerns about health problems. However, there has been limited study in which Cr levels were measured in tannery workers, who are chronically exposed to Cr. Our preliminary inspection showed that there was hyperpigmented skin in tannery workers. We therefore investigated the correlation between skin pigmentation levels digitally evaluated as L* values by using a reflectance spectrophotometer and Cr levels in skin appendages in 100 male tannery workers and in 49 male non-tannery workers in Bangladesh. Digitalized skin pigmentation levels of the face and feet in addition to Cr levels in hair and toenails in tannery workers were significantly higher than those in non-tannery workers in our univariate analysis. Spearman's rank correlation coefficient analysis showed significant correlation between duration of tannery work (years) and Cr levels in hair (r = 0.62) and toenails (r = 0.61). Our multivariate analysis also showed that Cr levels in hair and toenails were significantly correlated with digitalized skin pigmentation levels of the face and feet in addition to duration of tannery work in all participants. Thus, our results showed the development of hyperpigmented skin in tannery workers. Our results also suggested that hyperpigmented skin could be a useful diagnostic marker for chronic exposure to Cr. Furthermore, cutaneous L* value might be a convenient marker for detection of chronic Cr poisoning, since the digitalized values enable objective evaluation of skin pigmented levels by general people as well as dermatologists.

Concentration of chromium in whole blood and erythrocytes showed different relationships with serum apolipoprotein levels in Cr(VI) exposed subjects

OBJECTIVE

To explore the effects of hexavalent chromium [Cr(VI)] on apolipoprotein(Apo) metabolism.

METHODS

One hundred and six long-term Cr(VI) exposed subjects and fifty five non-exposed individuals were recruited. The blood metals, glucose and lipid parameters were measured to evaluate the effects of hexavalent chromium on the apolipoproteins.

RESULTS

The quantity and homeostasis of multi-elements were significantly different between Cr(VI)exposed subjects and the controls(P < 0.05). The levels of serum TG, FPG, LDL-C, Apo AI, AII, CII, CIII, E and Lp(a) also changed significantly (P < 0.05). Concentration of chromium in whole blood and erythrocytes had different relationships with serum apolipoprotein levels in Cr(VI)exposed subjects.

CONCLUSIONS

Exposure of hexavalent chromium could significantly change the homeostasis of multi-elements as well as the levels of serum apolipoproteins. Cr(III) and Cr(VI)may have different effects on the apolipoproteins.

Occupational chemical exposure and diabetes mellitus risk

Diabetes mellitus (DM) is a group of metabolic diseases that may originate from an interaction between genetic and lifestyle risk factors. However, the possible role of occupational chemical exposures in the disease development and progression remains unclear. Therefore, this review aimed to provide a comprehensive evaluation of the relationship between occupational exposure to specific chemical substances or industrial activities and DM morbidity and mortality outcomes. Although some positive findings may support the diabetogenic role of certain pesticides and dioxins in different workplaces, the variable conditions of exposure, the lack of quantitative environmental or biological monitoring data and the different outcomes evaluated do not allow defining a specific exposure-disease causality. Therefore, further epidemiological studies will be necessary to adequately assess modes of action for different substances, dose–response relationships as well as individual susceptibility factors potentially affecting the exposure-disease continuum. Overall, this appears important to adequately assess, communicate and manage risks in occupational chemical exposure settings with the aim to protect workers and build healthier job conditions for diabetic employees.

Chromium picolinate supplementation for overweight or obese adults

BACKGROUND

Obesity is a global public health threat. Chromium picolinate (CrP) is advocated in the medical literature for the reduction of bodyweight, and preparations are sold as slimming aids in the USA and Europe, and on the Internet.

OBJECTIVES

To assess the effects of CrP supplementation in overweight or obese people.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE, ISI Web of Knowledge, the Chinese Biomedical Literature Database, the China Journal Full text Database and the Chinese Scientific Journals Full text Database (all databases to December 2012), as well as other sources (including databases of ongoing trials, clinical trials registers and reference lists).

SELECTION CRITERIA

We included trials if they were randomised controlled trials (RCT) of CrP supplementation in people who were overweight or obese.We excluded studies including children, pregnant women or individuals with serious medical conditions.

DATA COLLECTION AND ANALYSIS

Two authors independently screened titles and abstracts for relevance. Screening for inclusion, data extraction and 'Risk of bias'assessment were carried out by one author and checked by a second. We assessed the risk of bias by evaluating the domains selection,performance, attrition, detection and reporting bias. We performed a meta-analysis of included trials using Review Manager 5.

MAIN RESULTS

We evaluated nine RCTs involving a total of 622 participants. The RCTs were conducted in the community setting, with interventions mainly delivered by health professionals, and had a short- to medium-term follow up (up to 24 weeks). Three RCTs compared CrPplus resistance or weight training with placebo plus resistance or weight training, the other RCTs compared CrP alone versus placebo.We focused this review on investigating which dose of CrP would prove most effective versus placebo and therefore assessed the results according to CrP dose. However, in order to find out if CrP works in general, we also analysed the effect of all pooled CrP doses versus placebo on body weight only.Across all CrP doses investigated (200 μg, 400 μg, 500 μg, 1000 μg) we noted an effect on body weight in favour of CrP of debatable clinical relevance after 12 to 16 weeks of treatment: mean difference (MD) -1.1 kg (95% CI -1.7 to -0.4); P = 0.001; 392 participants;6 trials; low-quality evidence (GRADE)). No firm evidence and no dose gradient could be established when comparing different doses of CrP with placebo for various weight loss measures (body weight, body mass index, percentage body fat composition, change in waist circumference).Only three studies provided information on adverse events (low-quality evidence (GRADE)). There were two serious adverse events and study dropouts in participants taking 1000 μg CrP, and one serious adverse event in an individual taking 400 μg CrP. Two participants receiving placebo discontinued due to adverse events; one event was reported as serious. No study reported on all-cause mortality,morbidity, health-related quality of life or socioeconomic effects.

AUTHORS' CONCLUSIONS

We found no current, reliable evidence to inform firm decisions about the efficacy and safety of CrP supplements in overweight or obese adults.

Susceptibility to DNA damage in workers occupationally exposed to pesticides, to tannery chemicals and to coal dust during mining

Our mutagenesis group has been studying with important economic drivers of our state, such as agriculture, the foot-wear and leather industry and open-cast coal mining. Working conditions in these sectors have potentially harmful to humans. The aim of these studies is to determine the health risk of workers by biomonitoring subjects exposed to genotoxic agents. The main results of our studies with vineyard farmers we observed a high rate of MN and DNA damage in individuals exposed to pesticides (p < 0.001). In addition, some effects of genetic polymorphisms in the modulation of MN results were observed in this group. Tobacco farmers were also evaluated at different crop times. The results showed a significant increase in the Damage index and frequency in tobacco farmers compared to the non-exposed group, for all crop times. The results for footwear and tannery workers showed a significant increase in the mean ID for the solvent-based adhesive (p < 0.001) group in comparison to the water-based adhesive group and control (p < 0.05). For open-cast coal mine workers, the EBCyt indicated a significant increase in nuclear bud frequency and cytokinetic defects in the exposed group compared to the non-exposed group (p < 0.0001). We were able to associate specific genetic susceptibility with each type of exposure and with the non-use or improper use of personal protection equipment and diet adequacy. These results show how important the continuous education of exposed workers is to minimizing the effect of the occupational exposure and the risk of disease associated with the work.

Genotoxicity and oxidative stress in chromium-exposed tannery workers in North India

Trivalent chromium (Cr) is an environmental contaminant, which is extensively used in tanning industries throughout the world and causes various forms of health hazards in tannery workers. Therefore, a cross-sectional study design was used to evaluate the DNA damage and oxidative stress condition in tannery workers exposed to Cr in North India. The study population comprised 100 male tanners in the exposed group and 100 healthy males (no history of Cr exposure) in the comparable control group. Baseline characteristics including age, smoking, alcohol consumption habits and duration of exposure were recorded via interviewing the subjects. Blood Cr level (measured by atomic absorption spectrophotometry), DNA damage (measured by comet assay) and oxidative stress parameters (malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD)) were estimated in both the groups. As a result of statistical analysis, exposed group showed significantly higher level of Cr ( p < 0.0001), DNA damage ( p < 0.0001), MDA ( p < 0.0001), SOD ( p < 0.05) and lower level of GSH ( p < 0.001) when compared with controls. Smoking, alcohol consumption habits and age had no significant effect ( p > 0.05) on DNA damage and oxidative stress parameters in both the groups. In simple and multiple correlation analysis, DNA damage and oxidative stress parameters showed significant correlation with Cr level and duration of exposure in exposed group. The findings of the present study revealed that chronic occupational exposure to trivalent Cr may cause DNA damage and oxidative stress in tannery workers.

Hair-Pb longitudinal profiles and blood-Pb in the population of young Slovenian males

Hair-Pb longitudinal profiles of 25 mm hair length were measured in a population of Slovenian men (aged 18-25 years) using "tape sandwich" solid sampling electrothermal atomic absorption spectrometry (SS-ETAAS). From these data two parameters related to Pb exposure were deduced. Hair-Pb proximal (H-Pbprox.) denotes the Pb content of the proximal 3mm hair segment, while Hair-Pb average (H-Pbaver.) denotes the average Pb content of a 25 mm hair length. The former were found to be on average at least a factor of 2 lower than the H-Pbaver. values that are normally reported in the literature for hairs of 20-50 mm length. Hair-Pb gradient (H-Pbgrad.) defined as the difference in Pb content between the distal (25 mm) and the proximal (3 mm) hair segments divided by the hair length was found to be highly correlated to the level of air Pb pollution (R=0.9931; P<0.001; n=5), while association between H-Pbprox. and air-Pb was not significant (R=0.5765; P>0.05; n=5). Simultaneously, lead in whole blood (B-Pb) was determined by ETAAS as another parameter of Pb exposure. The frequency distribution of log B-Pb values followed a symmetrical Gaussian shape with a median value of 35 microg Pb/L. Log H-Pbprox. frequency distribution, on the contrary, showed a Poissonian shape. Transformation of the data revealed the existence of four homogeneous groups of males with different median H-Pbprox. values (40, 86, 326 and 2500 ng/g). The major proportion of the Slovenian male population ( approximately 70%) has H-Pbprox. contents between 60 and 600 ng/g. A weak but statistically significant association was found between logs H-Pbprox. and B-Pb (R=0.3957; P<0.05; n=247) but when only those subjects were retained whose both parameters were determined with reasonable accuracy and were either above or below the predetermined value (B-Pb=50 microg/L; H-Pbprox.=450 ng/g), substantial improvement in the strength of correlation was observed (R=0.7049; P<0.01; n=84). The poor strength of association between these parameters was attributed to the large variation in Pb intake and different kinetics of Pb appearance in hair and blood. This statement is consistent with reports dealing with the relationship between H-Pb and B-Pb found in the literature.

Occupational cancers in leather tanning industries: A short review

Work in leather tanning involves exposure to a wide range of chemicals. Some of these are carcinogens or suspected carcinogens. Increased risks for a number of cancers have been reported among the tannery workers. In the present review, a detailed account of lung cancer, testicular cancer, soft tissue sarcoma, pancreatic cancer, bladder cancer among tannery workers is mentioned.

Longitudinal hair chromium profiles of elderly subjects with normal glucose tolerance and type 2 diabetes mellitus

Longitudinal hair chromium (H-Cr) profiles in a group of patients with type 2 diabetes mellitus (n = 59; age, 62 +/- 9 years) and healthy elderly (control) subjects (n = 49; age, 59 +/- 10 years) matched by age and sex were measured by solid sampling electrothermal atomic absorption spectrometry, providing data on the magnitude of variation of Cr content along the hair length. H-Cr average (H-Cr(av)) and H-Cr proximal (H-Cr(pr))(.), relating to the average Cr content of the whole hair and the proximal 3-mm hair length, respectively, were also obtained. No significant difference between the healthy and diabetic group was found in mean H-Cr(av) or H-Cr(pr) contents (248 +/- 108 vs 247 +/- 143 and 233 +/- 98 vs 278 +/- 195 ng/g, respectively. However, women in the control group had significantly lower H-Cr values (P < .01) compared with men, but this difference was absent in the diabetic population. The distribution of log H-Cr(pr) values in the control population displayed a Gaussian shape, in contrast to the substantially wider distribution, skewed toward lower H-Cr(pr) values, observed in the diabetic group. The magnitude of variation in H-Cr content in the patient group over an interval of approximately 2 to 3 months (time of growth of the hair sampled) was found to be a factor of more than 2 larger than that in the control population (+/- 58% vs +/- 26%). A strong relationship (R = 0.656; P < .01) between log H-Cr(pr) and log fasting plasma Cr was observed in the diabetic group (n = 20). The mean fasting plasma Cr value of this group was 0.41 +/- 0.10 microg Cr per liter. No correlation between H-Cr(av.) and duration of diabetes was observed. A strong positive association was observed in the control population between H-Cr(pr) and fasting plasma insulin (n = 22; R = 0.6157; P < .01), and H-Cr(pr) and fasting plasma glucose (n = 24; R = 0.4118; P < .05), which is indicative of the interrelation of these parameters. In the control population, H-Cr(av) showed a slight decrease with age (n = 54; R = 0.2691; P < .05), which is assumed to be the result of increased insulin resistance caused by various age-associated factors including Cr deficiency. None of the above relationships was significant in the diabetic group. Evidence is presented that justifies the assumption that the longitudinal H-Cr profile resembles the variation in Cr metabolic rate over the time span of growing hair, which is not appreciably affected by external contamination. This suggests that glucose intolerance (type 2 diabetes mellitus) is an important factor that disturbs Cr metabolism.

Reproductive toxicity of chromium in adult bonnet monkeys (Macaca radiata Geoffrey). Reversible oxidative stress in the semen

The present study was designed to test the hypothesis that oxidative stress mediates chromium-induced reproductive toxicity. Monthly semen samples were collected from adult monkeys (Macaca radiata), which were exposed to varying doses (50, 100, 200 and 400 ppm) of chromium (as potassium dichromate) for 6 months through drinking water. Chromium treatment decreased sperm count, sperm forward motility and the specific activities of antioxidant enzymes, superoxide dismutase and catalase, and the concentration of reduced glutathione in both seminal plasma and sperm in a dose- and duration-dependent manner. On the other hand, the quantum of hydrogen peroxide in the seminal plasma/sperm from monkeys exposed to chromium increased with increasing dose and duration of chromium exposure. All these changes were reversed after 6 months of chromium-free exposure period. Simultaneous supplementation of vitamin C (0.5 g/L; 1.0 g/L; 2.0 g/L) prevented the development of chromium-induced oxidative stress. Data support the hypothesis and show that chronic chromium exposure induces a reversible oxidative stress in the seminal plasma and sperm by creating an imbalance between reactive oxygen species and antioxidant system, leading to sperm death and reduced motility of live sperm.

Proportionate cancer mortality among workers in the Belarussian tanning industry

BACKGROUND

The tanning industry involves many occupational exposures. This study evaluates proportionate cancer mortality among workers employed in the Belarussian tanning plant in Minsk.

METHODS

A total of 768 workers with seniority of not less than 6 months who were hired after January 1, 1953 and died before December 31, 2000 was investigated. Proportionate mortality ratios (PMRs) were calculated using the population of Minsk to generate expected numbers.

RESULTS

Among women employed in the tannery, there was a significant excess of pancreatic cancer, based on eight deaths (expected = 2.56, PMR = 3.13, 95% CI = 1.35-6.17). Six of the eight pancreatic cancer deaths occurred among women occupied in dyeing-stuffing workshops (expected = 1.64, PMR = 3.67, 95% CI = 1.34-7.97), all among workers hired between 1962 and 1984 (expected = 1.06, PMR = 6.54, 95% CI = 2.6-13.4).

CONCLUSIONS

Women in this tanning industry cohort experienced excess mortality of cancer of the pancreas, with suggested increases of corpus and cervix uteri, melanoma, and kidney cancers. For men, an insignificant increase in PMR of oral cavity-pharynx and pancreatic cancers was seen. Further prospective follow-up of living members of this cohort, will allow more in-depth analysis of rare cancer sites, latency, and duration of employment, and is warranted.