Effects of menopause on blood manganese levels in women: analysis of 2008-2009 Korean National Health and Nutrition Examination Survey data

Hair and Serum Trace Element and Mineral Levels Profiles in Women with Premenopausal and Postmenopausal Osteoporosis

The objective of the present study was to evaluate serum and hair trace element and mineral levels in women with osteoporosis, as well as to estimate the impact of menopausal status on the profile of trace element and mineral status in women with osteoporosis. 207 women with diagnosed osteoporosis 22-85 years-of-age, and 197 healthy women of the respective age participated in the present study. Analysis of the levels of mineral and trace element in hair and serum samples was performed by inductively-coupled plasma mass-spectrometry (ICP-MS). Women with osteoporosis were characterized by significantly lower hair Ca, Mg, Co, I, Li, and Mn levels, as well as serum Ca, Mg, Co, Fe, V, and Zn concentrations compared to women in the control group. After additional grouping according to menopausal status, the lowest hair Ca and Mg content was observed in postmenopausal osteoporotic women, whereas serum Ca and Mg concentrations were the lowest in premenopausal osteoporotic women. Hair Co, Mn, and Zn levels in postmenopausal osteoporotic women were lower than in healthy postmenopausal women. The lowest circulating Zn levels were observed in osteoporotic postmenopausal women. Taken together, decreased hair and serum levels in osteoporotic women are indicative of increased risk of Ca, Mg, Co, and Zn deficiency in women with osteoporosis. In turn, alterations in hair trace element and mineral levels in osteoporosis are more profound in postmenopausal women. Hypothetically, improvement in trace element and mineral metabolism especially in postmenopausal women may be considered as a potential strategy for mitigating osteoporosis.

Consequences of Disturbing Manganese Homeostasis

Manganese (Mn) is an essential trace element with unique functions in the body; it acts as a cofactor for many enzymes involved in energy metabolism, the endogenous antioxidant enzyme systems, neurotransmitter production, and the regulation of reproductive hormones. However, overexposure to Mn is toxic, particularly to the central nervous system (CNS) due to it causing the progressive destruction of nerve cells. Exposure to manganese is widespread and occurs by inhalation, ingestion, or dermal contact. Associations have been observed between Mn accumulation and neurodegenerative diseases such as manganism, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. People with genetic diseases associated with a mutation in the gene associated with impaired Mn excretion, kidney disease, iron deficiency, or a vegetarian diet are at particular risk of excessive exposure to Mn. This review has collected data on the current knowledge of the source of Mn exposure, the experimental data supporting the dispersive accumulation of Mn in the brain, the controversies surrounding the reference values of biomarkers related to Mn status in different matrices, and the competitiveness of Mn with other metals, such as iron (Fe), magnesium (Mg), zinc (Zn), copper (Cu), lead (Pb), calcium (Ca). The disturbed homeostasis of Mn in the body has been connected with susceptibility to neurodegenerative diseases, fertility, and infectious diseases. The current evidence on the involvement of Mn in metabolic diseases, such as type 2 diabetes mellitus/insulin resistance, osteoporosis, obesity, atherosclerosis, and non-alcoholic fatty liver disease, was collected and discussed.

Fundão tailings dam failure in Brazil: Evidence of a population exposed to high levels of Al, As, Hg, and Ni after a human biomonitoring study

BACKGROUND

On November 5th, 2015, the Fundão mine tailings dam in Minas Gerais State, Brazil, failed, releasing more than 50 million m³ of mud, rich in toxic metals. After that, a massive environmental disaster began with the mud wave flowing more than 600 km, until the mouth of Doce River, in Espírito Santo State, and finally reaching the Atlantic Ocean. A vast area was contaminated, affecting the ecosystem and several communities. Despite the tremendous environmental disaster, little is known concerning the population's exposure to toxic elements yet.

METHODS

Thus, a cross-sectional study was for the first time conducted in three communities directly affected by the disaster (Regência, Povoação, and Campo Grande) in Espírito Santo State, to evaluate the levels of 11 chemical elements (Al, As, Cd, Co, Cu, Hg, Mn, Ni, Pb, Se, and Zn) in blood. Sample analysis (n = 300) was performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS).

RESULTS

Our data show high levels of exposure to Al, As, Hg, and Ni. Mean values in blood were 60 μg/L (ranging from 9 to 434 μg/L), 10.9 μg/L (ranging from 5.81 to 269 μg/L), 6.4 μg/L (ranging from 0.05 to 103 μg/L) and 2.7 μg/L (ranging from 0.08 to 21 μg/L) for Al, As, Hg and Ni, respectively. Moreover, after applying a multiple regression model, we found community, drinking water, fish, seafood consumption, and smoking habits associated with metal/metalloid levels in their body. Well and tap water intake were identified as important sources of exposure to aluminum and nickel.

CONCLUSIONS

Our findings represent health risks to the groups living in the areas affected by the tailings dam failure, calling for further studies to evaluate the potential health effects of high exposure to metals and remediation actions from public health Brazilian authorities.

Determinants of Erythrocyte Lead Levels in 454 Adults in Florence, Italy

Background: Lead exposure, even at low levels, is associated with adverse health effects in humans. We investigated the determinants of individual lead levels in a general population-based sample of adults from Florence, Italy. Methods: Erythrocyte lead levels were measured (using inductively coupled plasma-mass spectrometry) in 454 subjects enrolled in the Florence cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC) study in 1992⁻1998. Multiple linear regression models were used to study the association between demographics, education and working history, lifestyle, dietary habits, anthropometry, residential history, and (among women) menstrual and reproductive history and use of exogenous sex hormones, and erythrocyte lead levels. Results: Median lead levels were 86.1 μg/L (inter-quartile range 65.5⁻111.9 μg/L). Male gender, older age, cigarette smoking and number of pack-years, alcohol intake, and residing in urban areas were positively associated with higher erythrocyte lead levels, while performing professional/managerial or administrative work or being retired was inversely associated with lead levels. Among women, lead levels were higher for those already in menopause, and lower among those who ever used hormone replacement therapy. Conclusions: Avoidable risk factors contribute to the lead body burden among adults, which could therefore be lowered through targeted public health measures.

μSex, pregnancy, and age-specific differences of blood manganese levels in relation to iron status; what does it mean?

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The interaction of iron with manganese (Mn) is the major factor affecting blood Mn level in general population.

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Children and pregnant women had no adverse effects from blood Mn levels associated with adverse effects in adult workers.

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The differences between a physiological and a pathological hypermanganesemia complicate the dose-response relationship.

The objective of the present study was to evaluate sex, menopause, pregnancy, and age-specific differences of blood manganese (Mn) levels in relation to iron status, and to assess the toxicological implications of these relationships. Females of childbearing age have higher concentrations of blood Mn than males because women have lower concentrations of ferritin. Previous studies indicated significant increases in blood Mn levels throughout pregnancy, and that the geometric mean of blood Mn was significantly higher in premenopausal women than postmenopausal women. This may be due to the enhanced absorption of Mn because of upregulation of iron absorption, which is especially important during late pregnancy. Mn concentrations are highest in infancy, decreased with age up to adolescence, and did not change during adulthood. Thus, the relationship of iron with Mn may be the major factor affecting blood Mn levels according to menstrual stage, reproductive status, menopausal factors, and age. However, Mn absorbed via the gastrointestinal system seems to be less neurotoxic than inhaled or parenteral Mn, due to the tight enterohepatic homeostatic control of this essential element. Furthermore, children and pregnant women had no adverse health effects from blood levels of Mn that were associated with adverse effects in adult workers. In conclusion, the differences between a physiological and a pathological hypermanganesemia complicate interpretation of the dose-response relationship.

Associations of Serum Manganese Levels with Prediabetes and Diabetes among ≥60-Year-Old Chinese Adults: A Population-Based Cross-Sectional Analysis

Older adults can experience glucose metabolism dysfunction, and although manganese may help regulate glucose metabolism, there is little information regarding this association among older people. This cross-sectional study included 2402 Chinese adults who were ≥60 years old in 2013 (Tianjin, China), and evaluated the associations of serum manganese with prediabetes and diabetes. Serum manganese levels were measured using inductively coupled plasma mass spectrometry. Multivariable logistic regression models were used to evaluate the sex-specific associations of manganese levels with diabetes and prediabetes after adjusting for confounding factors (age, sex, life style factors, and health status). Based on the WHO criteria, prediabetes was observed in 15.1% of men and 13.4% of women, while diabetes was observed in 30.0% of men and 34.4% of women. In the final model, the odds ratios (95% confidence interval) for prediabetes according to manganese quartile were 1.000, 0.463 (0.269–0.798), 0.639 (0.383–1.065), and 0.614 (0.365–1.031) among men and 1.000, 0.773 (0.498–1.200), 0.602 (0.382–0.947), and 0.603 (0.381–0.953) among women (p for trend = 0.134 and 0.015, respectively). The lowest prevalence of diabetes among men occurred at a moderate range of serum manganese (p < 0.05). Therefore, appropriate serum manganese levels may help prevent and control prediabetes and diabetes.

Blood metal concentrations of manganese, lead, and cadmium in relation to serum ferritin levels in Ohio residents

The objectives of this study were to assess ferritin-specific profiles of blood metal concentrations such as manganese, lead, and cadmium and to evaluate whether ferritin may affect the behavior of the blood metals in relation to menstruation, menopause, or sex in Ohio residents. Recruited participants included residents from Marietta, East Liverpool, and Mt. Vernon, OH, USA, who were aged 30-75 years and lived at least 10 years in their respective town. The levels of the neurotoxic metals such as manganese, cadmium, and lead were assayed in whole blood. Serum was analyzed for ferritin level [as a biomarker of iron (Fe) status]. An association between blood metal concentrations and independent variables (age, serum ferritin, manganese exposure status, and sex) by multiple regression analysis was assessed, controlling for various covariates such as BMI, educational level, smoking, and alcohol drinking status. Overall, the geometric means of blood manganese, cadmium, and lead levels of all participants (n = 276) were 9.307 μg/L, 0.393 μg/L, and 1.276 μg/dL, respectively. Log serum ferritin concentrations were inversely associated with log blood manganese concentration (β = -0.061 log ferritin and β = 0.146 categorical ferritin) and log blood cadmium concentrations (β = -0.090 log ferritin and β = 0.256 categorical ferritin). Log serum ferritin concentrations were not associated with log blood lead concentrations. Variables of age, sex, and exposure status were not associated with log manganese concentrations; however, log blood cadmium concentrations were higher in older population, women, and smokers. Log blood lead concentrations were higher in older population, men, and postmenopausal women. Our study showed that iron deficiency is associated with increased levels of blood manganese and cadmium, but not blood lead, in Ohio residents. These metals showed different toxicokinetics in relation to age, sex, and menopausal status despite similar relationships between ferritin and metal concentrations.

Sex- and age-differences in blood manganese levels in the U.S. general population: national health and nutrition examination survey 2011-2012

BACKGROUND

Manganese is an essential element, but excessive manganese exposure has neurotoxic effects.

OBJECTIVE

To examine blood manganese levels in the general population with respect to sex, age, race/ethnicity, pregnancy and menauposal status, as well as levels of trace elements in blood.

METHODS

We used data from the National Health and Nutrition Examination Survey, a national survey of U.S. residents (n = 7720 participants, ages 1 to 80 years). General linear models and generalized additive models were used to examine the association between blood manganese concentration and participants' characterisics, accounting for the complex survey design.

RESULTS

Blood manganese levels ranged from 1.6 to 62.5 μg/L, with arithmetic means of 10.6 and 9.2 μg/L for women and men, respectively. The following characteristics were significantly associated with higher blood manganese levels: female sex, younger age, Asian origin, and being pregnant. In addition, there were non-linear relationships between blood manganese levels and cadmium, iron, lead, and mercury levels.

CONCLUSION

The higher blood manganese levels observed among females suggest sex-related metabolic differences in the regulation of manganese, and elevated levels among pregnant women suggest an important role of manganese in reproduction. The present study supports the need to take into consideration age- and sex-related differences in blood manganese levels, as well as pregnancy status when examining manganese essentiality or toxicity.

Iron deficiency increases blood concentrations of neurotoxic metals in children

Iron deficiency affects approximately one-third of the world's population, occurring most frequently in children aged 6 months to 3 years. Mechanisms of iron absorption are similar to those of other divalent metals, particularly manganese, lead, and cadmium, and a diet deficient in iron can lead to excess absorption of manganese, lead, and cadmium. Iron deficiency may lead to cognitive impairments resulting from the deficiency itself or from increased metal concentrations caused by the deficiency. Iron deficiency combined with increased manganese or lead concentrations may further affect neurodevelopment. We recently showed that blood manganese and lead concentrations are elevated among iron-deficient infants. Increased blood manganese and lead levels are likely associated with prolonged breast-feeding, which is also a risk factor for iron deficiency. Thus, babies who are breast-fed for prolonged periods should be given plain, iron-fortified cereals or other good sources of dietary iron.

Sex-specific Profiles of Blood Metal Levels Associated with Metal-Iron Interactions

The mechanisms by which iron is absorbed are similar to those of divalent metals, particularly manganese, lead, and cadmium. These metals, however, show different toxicokinetics in relation to menarche or menopause, although their interaction with iron is the same. This review focuses on the kinetics of these three toxic metals (manganese, lead, and cadmium) in relation to menarche, pregnancy, and menopause. The iron–manganese interaction is the major factor determining sex-specific differences in blood manganese levels throughout the whole life cycle. The effects of estrogen overshadow the association between iron deficiency and increased blood lead concentrations, explaining why women, despite having lower ferritin concentrations, have lower blood lead concentrations than men. Iron deficiency is associated with elevated cadmium levels in premenopausal women, but not in postmenopausal women or men; these findings indicate that sex-specific differences in cadmium levels at older ages are not due to iron–cadmium interactions, and that further studies are required to identify the source of these differences. In summary, the potential causes of sex-specific differences in the blood levels of manganese, lead, and cadmium differ from each other, although all these three metals are associated with iron deficiency. Therefore, other factors such as estrogen effects, or absorption rate as well as iron deficiency, should be considered when addressing environmental exposure to toxic metals and sex-specific differences in the blood levels of these metals.