Chromium as a Risk Factor for Breast Cancer: A Meta-Analysis.

BACKGROUND: Chromium (Cr) is a transition metal, natural element. Chromium is the 21st most abundant element in Earth's crust. Cr is found in soil, rocks and living organisms. It may have various oxidation states, from -2 to +6, but most of these states are too unstable to exist in any significant quantities. The purpose of this review and meta-analysis is to critically assess the scientific evidence on the carcinogenic effects of chromium (Cr) and to determine whether there is currently sufficient evidence to suggest that that there is a link between chromium levels in hair and blood serum and breast cancer in women. MATERIAL AND METHODS: Research on the relationship between heavy metal chromium and the risk of developing breast cancer has been searched in PubMed, EMBASE, Web of Science, Scopus among papers published between January 2000 and September 2020. The search used the following terms (MeSH): breast cancer, women, trace elements, metals, chromium, chemically-induced, hair, serum using additional terms. RESULTS: In the second group of comparisons of women from "ecologically clean" districts of Aktobe Region, there were significantly lower indicators of the microelements in tumor tissue. The amount of Fe ranges from 38.46 to 65.39 ug/g (average 49.56±5.81 ug/g), Cu from 2.8 to 6.69 ug/g (average 5.06±1.01 ug/g), Zn from 1.89 to 5.38 ug/g (average 3.88±0.89 ug/g), Cr from zero to 6,1 ug/g (average 2.13±1.29 ug/g), Ni from 0.11 to 0.42 ug/g (average 0.28±0.067 ug/g) и Pb from zero to 0.19 ug/g (average 0.098±0.06 ug/g). CONCLUSION: The article established that women who live or work in ecologically polluted areas or have problems with micronutrient exchange need in-depth screening and more frequent screening for early detection of pre- and breast cancer.

Content of Essential Trace Elements in the Hair of Residents of the Caspian Region of the Republic of Kazakhstan Who Recovered from COVID-19.

This study aimed to investigate the content of essential elements in the hair of unvaccinated residents of the Caspian region who recovered from COVID-19. This cross-sectional study involved 260 unvaccinated permanent residents of Mangistau oblast aged 18−60. The diagnosis and severity of COVID-19 were based on clinical signs and symptoms, laboratory data, R-graph results, and oxygen saturation by the Clinical Protocol of the Ministry of Health of the Republic of Kazakhstan. Inductively coupled plasma mass spectrometry determined the content of trace elements cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), iodine (I), manganese (Mn), selenium (Se), and zinc (Zn). The content of Cr (p < 0.05), Cu (p < 0.05), Fe (p < 0.001), I (p < 0.05), Mn (p < 0.001), and Zn (p < 0.05) in the hair of individuals who had a coronavirus infection was lower than those who did not have this infection. There were significantly higher levels of Cu (p < 0.05) in the hair of participants who had moderate or severe COVID-19 compared to those with mild forms. The results of multiple regression analysis showed that in the presence of a COVID-19 infection in a subject's history, the content of Cr (0.871 (95% CI: 0.811; 0.936)), Cu (0.875 (95% CI: 0.803; 0.955)), Fe (0.745 (95% CI: 0.636; 0.873)), and Mn (0.642 (95%CI: 00.518; 0.795)) decreased in the hair. The data obtained indicate that past COVID-19 infections affect the trace element status of the inhabitants of the Caspian region of Kazakhstan.

Hair Toxic Trace Elements of Residents across the Caspian Oil and Gas Region of Kazakhstan: Cross-Sectional Study.

This study aimed to assess the relationship between the content of toxic trace elements, such as aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), mercury (Hg), and lead (Pb), in the hair of the adult population of western Kazakhstan and the distance of their residence from oil and gas fields. The cross-sectional study included 850 adults aged 18-60 years. Inductively coupled plasma mass spectrometry was used to measure the level of Al, As, Be, Cd, Hg, and Pb in hair. The relationship between the concentration of toxic trace elements in the hair and the distance from oil and gas fields was assessed in three groups (<16 km, 16-110 km, and >110 km), using multiple linear regression analysis. The highest concentration of Hg = 0.338 µg/g was determined in the group living near oil and gas fields (0-16 km), whereas the lowest concentration of Al = 3.127 µg/g and As = 0.028 µg/g was determined in participants living at a long distance (more than 110 km) (p < 0.001). The concentration of Al (-0.126 (CI: -0.174; -0.077)), Hg (-0.065 (CI: -0.129; -0.001)), and Pb (0.111 (CI: 0.045; 0.177)) is associated with the distance to oil and gas fields. The obtained data indicate a change in the toxic trace element content in the hair of residents in the Caspian region of western Kazakhstan, a change that is most pronounced in residents living in the zone of oil and gas pollution. The distance to the oil and gas fields affects the content of toxic elements in scalp hair. In particular, the concentration of Al and Hg is associated with a decrease in the distance to oil and gas fields, while the concentration of Pb is associated with an increase in the distance to these fields. The lowest content of Al and As was determined in the hair of study participants living in the most remote areas (more than 110 km from oil and gas fields). Our results demonstrate the need for the biomonitoring of toxic elements to determine long-term temporal trends in the impact of chemicals on public health in western Kazakhstan.

Essential Trace Elements in Scalp Hair of Residents across the Caspian Oil and Gas Region of Kazakhstan.

Most of the country's oil and gas fields are situated in West Kazakhstan, mainly on the Caspian Sea coast, causing significant damage to the local environment and contributing to an imbalance in the trace element composition of the human body. The study is aimed to evaluate the relationship between the concentration of essential trace elements in scalp hair of the western Kazakhstan adult population and the remoteness of their residence from oil and gas fields. The concentration of essential trace elements (Co, Cu, Fe, I, Mn, Se, Zn) in the hair of 850 individuals aged 18−60 years was determined by inductively coupled plasma mass spectrometry. In residents of settlements located at a distance of >110 km from oil and gas fields, the concentration of Cu and I in hair was significantly higher than in those closer to 110 km (p < 0.001). The content of Cu and I were associated with the distance to oil and gas fields (0.072 (95% CI: 0.050; 0.094)) and (0.121 (95% CI: 0.058; 0.185)), respectively. We detected a significant imbalance in the distribution of some essential trace elements in residents' scalp hair from the Caspian region of western Kazakhstan, living near oil and gas fields. The concentrations of Cu and I were significantly interrelated with the distance to oil and gas fields. The level of copper in the hair of both inhabitants of the area most remote from oil and gas facilities and the entire population of western Kazakhstan as a whole remains significantly low. The data obtained provide evidence of the possible impact of pollutants generated by the oil and gas facilities on a shortage of essential trace elements and associated subsequent health risks.

The effect of endurance and endurance-strength training on body composition and cardiometabolic markers in abdominally obese women: a randomised trial.

Studies comparing the effect of endurance and endurance-strength training on cardiometabolic markers provided inconsistent results. Therefore, the study aimed to compare the effect of endurance and endurance-strength training on body composition and cardiometabolic parameters in abdominally obese women. In this randomised trial, 101 subjects were included and divided into endurance (n = 52) and endurance-strength (n = 49) training. During the 12-week intervention, participants performed supervised one-hour training three times a week. Body composition, blood pressure (BP), markers of glucose and lipid homeostasis, and myoglobin levels were measured before and after the intervention. In total, 85 subjects completed the trial. Both interventions decreased fat mass and visceral adipose tissue and increased free fat mass, appendicular lean mass index and lean mass index. Neither endurance training nor endurance-strength training affected glucose and lipid metabolism. However, only endurance training significantly decreased paraoxonase and myoglobin levels. Both training programmes significantly decreased BP, with a more reduction of diastolic BP noted in the endurance group. In conclusion, both training programmes had a favourable effect on body composition but did not improve glucose and lipid homeostasis. Besides, endurance training decreased paraoxonase activity and myoglobin levels and was more effective in reducing BP.The study was registered with the German Clinical Trials Register (DRKS) within the number: DRKS00019832 (retrospective registration), date of registration: 26/02/2020.