Trace element biomonitoring in hair and blood of occupationally unexposed population residing in polluted areas of East Kazakhstan and Pavlodar regions

Serum levels of glycosylated hemoglobin, insulin, total protein and their association with somatoform disorder in environmentally exposed populations in Kazakhstan

Biochemical blood parameters may serve as biomarkers of environmental pollution, with somatoform disorder (SD) being of interest. This study examined serum glycosylated hemoglobin (HbA1C), insulin, total protein, and SD prevalence in populations from polluted areas in Kazakhstan. It assessed the predictive value of these parameters for SD, along with other risk factors. A cross-sectional study of 1881 individuals (ages 18-52) in Kazakhstan used the PHQ-15 questionnaire to assess SD. HbA1C was measured via immunoturbidimetry, insulin via immunoassay, and total protein via colorimetry. HbA1C levels > 6.5 % identified undiagnosed diabetes in 2.4 % of control residents, with higher rates in Ust-Kamenogorsk (10.6 %), Berezovka/Aksay (4.8 %), and Borodulikha/Abay (3.7 %). Pollutant-exposed populations had higher rates of hyperinsulinemia. Moderate to severe SD was more common in Ust-Kamenogorsk (26.6 %) and Berezovka/Aksay (27.2 %) than in controls, with lower rates in Borodulikha/Abay (16.7 %). Age, HbA1c levels, and residence near the condensate gas extraction plant significantly increased the odds of having moderate to severe SD, while being male and of Kazakh ethnicity significantly decreased the odds. The study links environmental exposure to increased rates of SD, diabetes, and insulin resistance.

Serum levels of thyroxine, thyroid-stimulating hormone, and anti-thyroid peroxidase antibodies and their association with anxiety in environmentally exposed populations in Kazakhstan

Little is known about the impact of environmental pollution on thyroid function in the non-occupationally exposed population of Kazakhstan. This study aimed to investigate serum levels of thyroxine (T4), thyroid-stimulating hormone (TSH), and anti-thyroid peroxidase (TPO) antibodies in the environmentally exposed population of Kazakhstan in relation to symptoms of anxiety. A total of 1,388 nominally healthy individuals residing in areas exposed to three major types of environmental pollution prevalent in Kazakhstan-non-ferrous metallurgy, condensate gas extraction, and activities of the Semipalatinsk Nuclear Test Site (SNTS)-were enrolled. All comparisons were made with 493 individuals residing in settlements without industrial or military pollution. Serum-free T4, TSH, and anti-TPO levels were tested using a solid-phase chemiluminescent immunoassay. The Generalized Anxiety Disorder 7-item (GAD-7) inventory was utilized to screen for anxiety symptoms. The prevalence of subclinical hypothyroidism was significantly higher in residents of settlements near the condensate gas field than in control sites (20.3 vs. 15.0%). In comparison, the prevalence of overt hypothyroidism was insignificantly higher (0.7 vs. 0.6%). The prevalence of subclinical hyperthyroidism was insignificantly higher in residents of settlements around the SNTS. The prevalence of overt hyperthyroidism was insignificantly higher in residents of areas proximal to the condensate gas field compared to the controls. The prevalence of both normal and elevated serum levels of anti-TPO antibodies did not differ significantly between different sites. Moderate and severe anxiety symptoms were the least common in residents of the two control sites (5.9%). This study carries potential implications for tailored public health interventions and policies.

Evaluate the Work-Related Exposure of Vanadium on Scalp Hair Samples of Outdoor and Administrative Workers of Oil Drilling Field: Related Health Risks

Petrochemical facilities, including oil well drilling, are discharging resources of extensive noxious waste into the environment. The workers in different sections might be exposed to vanadium (V) through different routes (groundwater and soil), which is linked with extensive physiological disorders, hypertension, respiratory disorders, anemia, skin, and gastrointestinal disorders. This study determined the contents of V in a biological sample (scalp hair) of workers of different categories (outdoor and office workers) in an oil drilling field in Sindh, Pakistan. The environmental samples, groundwater, bottled mineral water, and soil samples were also analyzed for V. For comparative purposes, the scalp hair of age-matched male subjects residing in domestic areas of Hyderabad city, Pakistan, was also analyzed. Generally, the concentrations of V in groundwater near the oil drilling field and drilled soil illustrated significant variations. The results show that the vanadium concentration in the scalp hair of non-exposed referents (controls) and office workers (exposed referents) was 62% and 45% lower than those observed for outdoor drilling and cleaning mud workers. It was observed that high exposure to V in outdoor workers might be linked with different physiological disorders such as anemia, eye problems, and bronchial disorders.

Serum calcium and magnesium levels and quality of life in environmentally exposed populations in Kazakhstan

The relationship between the levels of essential elements and various aspects of well-being in environmentally exposed populations still needs to be better understood. The present study aims to investigate the potential connections between serum concentrations of calcium (Ca), magnesium (Mg), and quality of life (QoL) in environmentally exposed populations in Kazakhstan. The present study involved 1881 nominally healthy individuals aged 18-52 years who were permanent residents of Abay, Borodulikha, Ust-Kamenogorsk, Kurchum, Uralsk, Aksay, and Berezovka settlements. These settlements were selected to represent different types of environmental exposure: radioactive fallout from the Semipalatinsk Nuclear Test Site (SNTS), non-ferrous metallurgy, and the condensate gas field, compared to environmentally unexposed territories. The Russian version of the SF-36 questionnaire was used to assess the participants' quality of life. Serum Ca levels were measured using colorimetry with O-cresolphthalein, and serum Mg concentrations were measured using colorimetry with xylidyl blue. Both elevated and decreased serum Ca levels were more frequently observed in the environmentally exposed populations. The prevalence of hypermagnesemia was highest among residents near the condensate gas field. Environmentally exposed populations residing near the SNTS and in Ust-Kamenogorsk exhibited lower scores in some QoL domains. In contrast, people near the condensate gas field showed comparable or even higher QoL scores than the control population. Only serum Mg demonstrated a significant association with the average QoL scores, while Ca did not show such an association. These findings have important implications for public health interventions.

Serum Levels of Cortisol and Adrenocorticotropic Hormone and their Association with Depression in Environmentally Exposed Populations in Kazakhstan

This study aimed to investigate the serum levels of cortisol and adrenocorticotropic hormone (ACTH) and the prevalence of depression in the environmentally exposed population of Kazakhstan compared to the environmentally unexposed populations. Additionally, the study aimed to evaluate the capacity of cortisol and ACTH to predict moderate and severe depression in populations exposed to environmental risk factors. This cross-sectional study included 1881 nominally healthy individuals aged between 18-52 years who were lifelong residents of Abay, Borodulikha, Ust-Kamenogorsk, Aksay, and Berezovka settlements, which are characterized by exposure to various types of environmental pollutants. Comparisons were made with residents of control sites with no known industrial or radioactive pollution (Uralsk and Kurchum). The Russian version of the PHQ-9 questionnaire was used to evaluate the presence and severity of depression. Serum cortisol levels were measured using solid-phase chemiluminescent immunoassay, while serum ACTH levels were tested with chemiluminescent assays. Populations exposed to environmental pollution from condensate gas extraction (Berezovka and Aksay) had higher median serum cortisol concentrations. However, the populations of the two controls had the highest median serum levels of ACTH. The median total PHQ-9 scores were the lowest in residents of control sites, which also had the highest proportion of individuals with no or minimal depression. Both serum cortisol and ACTH identified moderate, moderately severe, and severe depression. The findings highlight the potential impact of environmental pollution on stress hormone levels and depression, calling for further research and public health interventions to address this issue.

Fish and Seafood Safety: Human Exposure to Toxic Metals from the Aquatic Environment and Fish in Central Asia

Toxic metals that are released into aquatic environments from natural and anthropogenic sources are absorbed by aquatic organisms and may threaten the health of both aquatic organisms and humans. Despite this, there have been limited studies on the metal concentrations in fish and humans in Central Asia. This study summarizes the presence of the toxic metals arsenic (As), mercury (Hg), cadmium (Cd), and lead (Pb) in aquatic bodies, fish, and seafood products and conducts a risk assessment. While certain areas show a notable increase in fish and seafood consumption, the overall intake in Central Asia remains below recommended levels. However, in regions with high fish consumption, there is a potential for elevated exposure to toxic metals, especially Hg. The risk of exposure to toxic metals in fish and seafood in Central Asia emerges as a significant concern. Comprehensive monitoring, regulation, and remediation efforts are imperative to ensure the safety of water sources and food consumption in the region. Public awareness campaigns and the establishment of dietary guidelines play a crucial role in minimizing the health risks associated with consumption.

Exposure to multiple metals in adults and diabetes mellitus: a cross-sectional analysis

Diabetes mellitus (DM) is the most widely recognized metabolic illness with expanding morbidity among ongoing years. Its high incapacity rate and death rate badly affect individuals' quality of life. Increasing proofs backed the relationship between metal exposures with the risk of DM, but the methodological boundedness cannot clarify the complexity of the internal relationship of metal mixtures. We fitted the logistic regression model, weighted quantile sum regression model, and Bayesian kernel machine regression model to assess the relationship between the metal exposures with DM in adults who participated in the National Health and Nutrition Examination Survey 2013-2016. The metals (lead, cadmium, and copper) levels were significantly higher among diabetic compared to the healthy controls. In the logistic regression model established for each single metal, lead and manganese were associated with DM in both unadjusted and mutually adjusted models (highest vs. lowest concentration quartile). When considering all metal as a mixed exposure, we found a generally positive correlation between metal mixtures with DM (binary outcome) and glycohemoglobin (HbA1c) levels (continuous outcome). Exposure to metal mixtures was associated with an increased risk of DM and elevated levels of HbA1c.

Potentially toxic elements in human scalp hair around China's largest polymetallic rare earth ore mining and smelting area

There is a growing concern about human health of residents living in areas where mining and smelting occur. In order to understand the exposure to the potentially toxic elements (PTEs), we here identify and examine the cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in scalp hair of residents living in the mining area (Bayan Obo, n = 76), smelting area (Baotou, n = 57) and a reference area (Hohhot, n = 61). In total, 194 hair samples were collected from the volunteers (men = 87, women = 107) aged 5-77 years old in the three areas. Comparing median PTEs levels between the young and adults, Ni levels were significantly higher in adults living in the smelting area while Cr was highest in adults from the mining area, no significant difference was found for any of the elements in the reference area. From the linear regression model, no significant relationship between PTEs concentration, log10(PTEs), and age was found. The concentrations of Ni, Cd, and Pb in hair were significantly lower in the reference area when compared to both mining and smelting areas. In addition, Cu was significantly higher in the mining area when compared to the smelting area. Factor analysis (FA) indicated that men and women from the smelting area (Baotou) and mining area (Bayan Obo), respectively, had different underlying communality of log10(PTEs), suggesting different sources of these PTEs. Multiple factor analysis quantilized the importance of gender and location when combined with PTEs levels in human hair. The results of this study indicate that people living in mining and/or smelting areas have significantly higher PTEs (Cu, Ni, Cd, and Pb) hair levels compared to reference areas, which may cause adverse health effects. Remediation should therefore be implemented to improve the health of local residents in the mining and smelting areas.

Potentially toxic elements exposure biomonitoring in the elderly around the largest polymetallic rare earth ore mining and smelting area in China

Potentially toxic elements (PTEs) can be released during mining operations and ore processing. The pollution and health risk related to PTEs in total suspended particulates (TSPs) around the largest polymetallic rare earth mining area (Bayan Obo) and smelting area (Baotou) in Inner Mongolia, China, were evaluated. PTEs in the hair of the elderly living in these two areas and a reference area (Hohhot) were also examined. Relationships between PTEs in TSPs and hair with categorical factors (location, gender, etc.) were also modeled. Multivariate statistical analyses were carried out to analyze the possible sources of the PTEs in TSPs. The bubble maps of the concentrations of PTEs indicated that high concentrations of PTEs were near the industrial area where smelting plants and power plants were located. In addition, health risks were assessed for adults in the mining and smelting area. The carcinogenic risk of Cr was high for residents in the study areas. Also, the residents were exposed to a non-carcinogenic risk of Ni. Significant mean value differences were observed between PTEs in the hair of the elderly in Baotou and Hohhot. Results of the linear regression model indicated that around 31 % of the Pb in hair could be explained by the linear regression model, it could be affected by Ni and Zn in TSPs, but location, gender, and sampling time showed no significant contribution. Age was not significantly associated with the PTEs levels in hair in Baotou and Bayan Obo. The results provide important scientific evidence for a better understanding of the effects of PTEs in TSPs in polymetallic ore mining and smelting areas.

Distribution Characteristics and Influencing Factors of Bio-elements in the Human Hair of Uyghur Communities in an Oasis Area of Xinjiang, China

Located in central Asia, Xinjiang is characterized as a diverse environment in China, consisting of vast deserts, dotted oases, and high mountains. Due to the combined effect of climate conditions under such a diverse environment, there are large differences in human activities, living styles, and eating habits in farmland and grazing pastures between Xinjiang and other regions of China. This study aimed to investigate the variations and mechanisms of elemental distribution in the hair of Uyghur communities among different ages and genders and under different land use backgrounds in an oasis region in Xinjiang. Hair samples from 524 residents from four traditional farmland areas and two grazing pasture areas in Bai Cheng County in Xinjiang were collected, and the levels of thirteen elements were analyzed. The results indicated that the average levels of Cu, Mg, Mn, Zn, Ni, Co, Pb, Fe, Ca, Cd, Cr, As, and Se in the hair of Uyghur communities were within the background levels of Chinese and global residents' hair. Overall, the levels of elements in the hair of women residents were higher than those of men residents. The levels of elements in the human hair of the middle-aged group were higher than those of child and older-aged groups. Elements Cr and Se in the hair of grazing pastures were higher than those of farmland areas. The levels of Cd, Pb, As, and Zn in the hair of farmland areas were higher than those of grazing pasture areas. The levels of Ca, Mg, Cu, and Fe in the hair of Uyghur communities were higher than those of other ethnic groups, while the toxic elements in the hair of residents in Bai Cheng were lower than those in other regions of China. Middle-aged people were exposed to higher levels of toxic elements in their daily activities compared to elderly and child groups. Also, adult groups need much more nutrients for their growth and intellectual development compared to child and elderly groups. The change in land use from grazing pastures to farmland increased the toxic trace element concentration levels in human hair. The significant differences in the overall concentration levels of elements in human hair among the different ethnic groups and regions can be attributed to the differences in lifestyles, cultural customs, dietary habits, and internal and external exposure routes.

Epitopes specificity of antibodies to thyroid peroxidase in patients with Graves’ disease, Hashimoto’s thyroiditis and overlap-syndrome

•

Further research that may shed light on specificity of MAbs in various TAIDs is strongly needed.

•

Heterogeneity of epitopes recognized by anti-TPO in patients with HT, GD and overlap-syndrome may help to clarify specificity of MAbs in various TAIDs.

•

Various MAbs in HT, GD and overlap-syndrome is different and this might be influenced by concentration of TPO in blood serum.

Background

Antibodies against thyroid peroxidase (anti-TPO) serve as clinical markers of thyroid autoimmune diseases (TAIDs). By trying to elucidate the causes of heterogeneity in autoantibody levels among patients with different TAIDs it becomes possible to clarify the pathophysiology of GD and HT.

Objective

To investigate the heterogeneity of epitopes recognized by anti-TPO in patients with Hashimoto’s thyroiditis (HT), Graves’ disease (GD) and overlap-syndrome.

Methods

We carried out a cross-sectional study on 398 patients with GD, HT and overlap syndrome and analyzed the specificity of epitopes and binding constants of TPO with monoclonal antibodies (MAbs). Ten MAbs to TPO were used, of which five were reactive with native TPO and the rest were reactive with denaturated TPO.

Results

The autoantibodies in blood serum of HT patients inhibited the binding of MAb63 more significantly than those in serum of GD patients: 59.62 % versus 54.02 %, respectively (p = 0.001). The anti-TPOs in serum of GD patients inhibited the binding of MAb77 more significantly than those in serum of HT patients: 54.36 % versus 51.13 %, respectively (p = 0.047). The binding of MAb45 was more inhibited in serum of patients with anti-TPO concentration over 1000 IU/ml (58.36 %). The blood serum of patients with overlap-syndrome showed less significant inhibition of MAb63 binding than that of patients with no overlap-syndrome: 52.47 % versus 58.81 %, respectively (p = 0.043).

Conclusion

Mapping the epitopes to TPO with the help of MAbs may improve the differential diagnosis between different thyroid autoimmunities.

Distribution and health-ecological risk assessment of heavy metals: an endemic disease case study in southwestern China

This research focuses on the health risks caused by heavy metal (HM) environmental pollution. Soil, water, corn, rice, and patients' hair samples from Daping Village, Yunnan Province, China, were analyzed for seven selected HMs. Geoaccumulation index (I_geo), pollution indexes (PI), and the Nemerow integrated pollution index (PN) were used to evaluate pollution levels. We employed principal component analysis (PCA), correlation analysis (CA), and spatial distribution to identify the source and distribution characteristics of HMs in soil. Health risks of HMs and exposure pathways were accessed by calculating the hazard quotient (HQ) and hazard index (HI). The I_geo, PI, and PN results show that cadmium (Cd) and arsenic (As) pollution is severe in soil, while other pollution is relatively little. PCA, CA, and spatial distribution show that HMs may be derived from black shale weathering and enrichment. Residents' drinking water is relatively safe. Arsenic is the element most threatening to local residents (HI = 3.8). Soil (HI = 3.55) ingestion and plant (HI = 1.67) ingestion are the primary exposure pathways to HMs. This unusual disease may be caused by children's relatively low immunity and long-term exposure to As. We must enhance the protection of children and encourage avoiding soil contact as much as possible. Our results highlight the importance of investigating HM pollution from geological sources and blocking potential exposure pathways.

Assessment of Distribution of Potentially Toxic Elements in Different Environmental Media Impacted by a Former Chlor-Alkali Plant

Former industrially contaminated sites are a burden from the past that still pose environmental risks. During the second half of the 20th century, the Pavlodar region in North Kazakhstan had been a part of Soviet Union’s industrial system that operated a chlor-alkali plant (CAP). The former CAP discharged approximately 135 t Hg into nearby Lake Balkyldak with total losses to water, soil, and air estimated around 1000 t. Pollution by potentially toxic elements (PTEs) due to former and currently active industrial enterprises is an under-investigated concern in the Pavlodar region. The present study aims to provide a much-needed update on the situation around the CAP area by evaluating the contamination by Hg and other selected PTEs (As, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, Se, Zn) on the surrounding environment of the CAP and in the nearby urban zone. Soil, sediment, surface water, and groundwater samples have been collected in several sampling campaigns carried out in 2018 and 2019. Several samples had Hg concentrations exceeding maximum permissible concentrations (MPC), for soils and sediments (in mg/kg; range: 0.0006 to 24, average: 0.56) and for surface water and groundwater (in µg/L; range: 0.004 to 1340, average: 93). Critically high concentrations were mostly measured in the vicinity of Lake Balkyldak, where the majority of Hg had been discharged by the former CAP, indicating persisting Hg pollution in the studied zone. A comparison of the PTEs concentrations in soil and sediments showed less severe pollution but still some elevated values for As, Ba, Co, Cu, Mn, Ni, and Se. The inter-elemental relationship between Hg and assessed PTEs was weak, indicating the presence of sources independent from Hg emitting sources. Further research on Hg contamination on the exact territory of the former CAP is needed, and a detailed human health risk characterization to identify potential unacceptable risks is strongly recommended.

Hair mineral analysis in the population of students living in the Lower Silesia region (Poland) in 2019: Comparison with biomonitoring study in 2009 and literature data

The paper presents a comparative analysis of biomonitoring research results using hair mineral analysis today and 10 years ago. The aim of the present work was to examine the impact of individual factors, on the content of elements in human hair. The mineral analysis of 115 hair samples was carried out using ICP-OES and AAS technique. It was shown that calcium, barium, copper, mercury, magnesium, manganese and selenium content depend on gender and is higher for women. Statistically significant synergistic correlations were identified between the following pairs of elements: (Ca-Mg), (P-S), (Mo-Sb) and (Ba-Pb). The results of the present work were compared with the previous assessment in 2009 on students of the same age. The content of most of the heavy metals in hair was reduced significantly, which is a sign of the improving state of the local environment. The greatest decrease was recorded for silver (96.6%), arsenic (93.4%), mercury (45.1%), lead (67.7%), antimony (55.2%), thallium (10 times) and cobalt (93.7%). The level of the following elements increased: Ba: 27.3%, Cu: 28.5%, Ni: 22.4%, Ti: 191%, Zn: 11.0%. Changes in the content of most heavy metals in hair have been noted, as well as changes of reference ranges, which may indicate an improvement in the state of the environment in Wrocław, Lower Silesia (Poland) over the last 10 years. These results were confirmed by biomonitoring studies carried out with human hair, which was shown to be a reliable biomarker of human exposure to toxic elements.

Analysis of the association of BRAFV600E mutation and Ki-67 overexpression with clinical and pathological characteristics in papillary thyroid cancer

In recent years, many studies were dedicated to the search for genetic markers in thyroid malignancies, including papillary thyroid cancer. This study was designed to investigate the prevalence of BRAFV600E mutation in the PTC in the Kazakh population, to evaluate the relationship between BRAF V600E mutation status and the clinicopathological features of PTC. Besides, we aimed at assessing of the relationship between the high proliferation index and the clinicopathological features of PTC and also between the concomitant coexistence of BRAFV600E and the high proliferative index with clinicopathological features of PTC. We carried out a cross-sectional study on 123 patients with PTC of Kazakh ethnicity and analyzed their clinical, laboratory, and genetic findings. The study groups were pooled based on the presence of mutated or wild-type BRAFV600E and quantitative assessment of Ki-67 marker expression. In the course of our study, we found that the age of patients from the group of BRAF gene mutation was significantly higher than that of patients from the wild-type group (48.63 ± 14.07 years versus 40.23 ± 14.34 years) (t = - 3.257; p = 0.001). Correlation analysis between BRAF mutation, Ki-67 expression, their combination and various clinical and pathological parameters in PTC patients showed that older age was positively correlated with higher frequency of mutant BRAF gene (r = 0.284; p < 0.001), while more advanced stage of tumor was positively correlated with higher expression of Ki-67 (r = 0.307; p < 0.001). To understand the significance of detecting the BRAFV600E mutation and an increased level of Ki-67 expression in the choice of patient therapy tactics, larger studies are required with patient survival as one of the primary outcomes.

Air Quality and Industrial Emissions in the Cities of Kazakhstan

Industrial emissions are of major concern, especially in developing countries. Hence, there is a need for studies that investigate the trends in industrial emissions in these countries. The purpose of this study is to discuss trends in industrial emissions in Kazakhstan and the air pollution level in its industrial cities. Data on emission limit values from the permitting documents of twenty-one power plants and nine metallurgical enterprises of Kazakhstan were analyzed. Eight cities (out of fourteen) had a “high” level of atmospheric air pollution according to the Air Pollution Index in 2019. Most of the considered enterprises increased their emission limit values compared to the previous permitting period. In some cities there is a lack of monitoring stations, indicating the need for improving the spatial coverage of the air quality monitoring network in the industrial cities of Kazakhstan. The location of industrial plants far outside the cities could reduce the exposure of the urban population to air pollution. Kazakhstan urgently needs to adopt stringent emissions standards for coal-fired power plants and heavy industrial plants. The national air quality standards and definitions of air pollutants need to be updated based on the latest scientific knowledge.

Environmental, Neuro-immune, and Neuro-oxidative Stress Interactions in Chronic Fatigue Syndrome

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS) is a complex, multisystem disease that is characterized by long-term fatigue, exhaustion, disabilities, pain, neurocognitive impairments, gastrointestinal symptoms, and post-exertional malaise, as well as lowered occupational, educational, and social functions. The clinical and biomarker diagnosis of this disorder is hampered by the lack of validated diagnostic criteria and laboratory tests with adequate figures of merit, although there are now many disease biomarkers indicating the pathophysiology of CFS. Here, we review multiple factors, such as immunological and environmental factors, which are associated with CFS and evaluate current concepts on the involvement of immune and environmental factors in the pathophysiology of CFS. The most frequently reported immune dysregulations in CFS are modifications in immunoglobulin contents, changes in B and T cell phenotypes and cytokine profiles, and decreased cytotoxicity of natural killer cells. Some of these immune aberrations display a moderate diagnostic performance to externally validate the clinical diagnosis of CFS, including the expression of activation markers and protein kinase R (PKR) activity. Associated with the immune aberrations are activated nitro-oxidative pathways, which may explain the key symptoms of CFS. This review shows that viral and bacterial infections, as well as nutritional deficiencies, may further aggravate the immune-oxidative pathophysiology of CFS. Targeted treatments with antioxidants and lipid replacement treatments may have some clinical efficacy in CFS. We conclude that complex interactions between immune and nitro-oxidative pathways, infectious agents, environmental factors, and nutritional deficiencies play a role in the pathophysiology of CFS.

Vitamin D deficiency in Kazakhstan: Cross-Sectional study

Vitamin D deficiency (VDD) is one of the serious and highly debatable public health problems affecting at least one billion of world population. This study objected to evaluate Vitamin D status in adult population of both sexes residing in different geographical areas of Kazakhstan and to elucidate the possible contributing factors related to VDD. This cross-sectional study covered 6 regions of Kazakhstan and applied the systematic random sampling to recruit 1347 healthy adults (of whom 819 were females) with mean age 44 ± 14 years. The concentration of 25-hydroxy vitamin D (25-OHD) was measured from May 2018 to August 2018 with Architect 25OH Vitamin D assay (Abbott Ireland Diagnostics Division Lisnamuck, Longford Co. Longford Ireland). Vitamin D deficiency was defined as 25-OHD values not exceeding 20 ng/mL as a reference threshold in healthy population. The median serum 25(OH)D concentrations in all studied regions of Kazakhstan were below the reference threshold (20 ng/mL). The lowest range of vitamin D (<10 ng/mL) was observed more commonly in females (34.6 % - 283) as compared to males (16.7 % - 88) and was significantly higher in Asians (33.2 % - 352) in contrast with Caucasians (6.7 % - 19) (χ2 = 177,939; D.f. = 3; p-value=<0,001). The proportion of severe VDD was higher in individuals with low body mass index (31.1 % - 188) vs. individuals with high body mass index (18.7 % - 50). In this study individuals aged 60 years and older had the most favorable situation with 25-OHD concentrations since these were normal in 14.4 % of observations (χ2 = 26,589; D.f. = 6; p-value=<0001). Studying the prevalence of VDD is an important public health task. Further research is needed to understand the epidemiology of VDD in more details to tailor intervention programs.