Copper and selenium status of healthy pregnant women in Enugu, southeastern Nigeria

Variations in Blood Copper and Possible Mechanisms During Pregnancy

Copper (Cu), an essential trace element, is crucial for both the mother and fetus. Currently, an increasing number of studies have focused on blood copper levels during pregnancy. Studies have found that blood copper levels in pregnant women are higher than those in reproductive-age women, but the trend, mainly in the 2nd and 3rd trimester, is still controversial. Most studies showed that blood copper levels gradually increased during pregnancy, while some studies found that blood copper levels remained stable or even decreased in the 3rd trimester. The possible mechanisms of variations in blood copper during pregnancy include the influence of estrogen (hepatic uptake and excretion, ceruloplasmin synthesis, maternal-fetal transport, etc.), the interaction of other trace elements (Fe, Zn, etc.) and other factors. Among them, maternal-fetal copper transport caused by elevated estrogen may be the main reason for the inconsistencies observed in the 2nd and 3rd trimester during pregnancy. However, there are some mechanisms require further investigation. In the future, the trend and mechanisms of blood copper during pregnancy should be explored more deeply to help doctors better monitor copper status and detect copper abnormalities in time.

Potential role of selenium in modifying the effect of maternal methylmercury exposure on child neurodevelopment - A review

Selenium (Se) is an essential trace element for normal neurodevelopment. It is incorporated into multiple selenoenzymes which have roles in the brain and neurological function, the synthesis of thyroid hormones, the antioxidant defense system, DNA synthesis, and reproduction. Fish is a source of both Se and neurotoxic methylmercury (MeHg). Selenium is known to ameliorate the effects of MeHg in experimental animals, but studies in children exposed to both Se and MeHg through prenatal fish consumption have been inconclusive. Research on Se's implications for pregnancy and child neurodevelopment is limited. The aims of this review are to summarize the literature on the biological roles of Se during pregnancy and the potential role in mitigating the effects of MeHg exposure from fish consumption on human health. This review has shown that Se concentrations among pregnant women globally appear insufficient, with the majority of pregnant women reporting Se concentrations below 70 µg/L during pregnancy. The role of Se in child development and its interactions with MeHg in children are inconclusive. Further investigation of the interaction between Se and MeHg in relation to child neurodevelopment in high fish-eating populations is required to fully elucidate effects.

Maternal antioxidant micronutrient deficiencies among pre-eclamptic women in Enugu, Nigeria: a cross-sectional analytical study

OBJECTIVES

To determine the prevalence of antioxidant micronutrient deficiencies in pregnant women with pre-eclampsia and healthy pregnant women, and to assess the relationships between trace element deficiency in pregnancy and the severity of pre-eclampsia in Enugu, Nigeria.

METHODS

We performed a secondary analysis of a cross-sectional analytical study of serum concentrations of copper, selenium, zinc, magnesium, and manganese in 81 pregnant women with pre-eclampsia and healthy pregnant women (controls) who were matched for age, gestational age, body mass index, and parity. This study was performed at the University of Nigeria Teaching Hospital, Ituku-Ozalla, Enugu. Participants' sera were analyzed with an atomic absorption spectrophotometer.

RESULTS

Trace element deficiencies were common and similar between women with pre-eclampsia and controls. However, women with pre-eclampsia were more likely to be deficient in manganese than controls (odds ratio = 2.28, 95% confidence interval: 1.90-2.75). Among the micronutrients studied, only manganese concentrations were significantly lower in women without severe symptoms of pre-eclampsia than in those with severe symptoms of pre-eclampsia.

CONCLUSIONS

Micronutrient deficiency is common in pregnant women with pre-eclampsia and in healthy pregnant women in Enugu, Nigeria. Only manganese deficiency is higher in women with pre-eclampsia than in healthy pregnant women.

Selenium and Redox Enzyme Activity in Pregnant Women Exposed to Methylmercury

Selenium (Se) is a micronutrient with essential physiological functions achieved through the production of selenoproteins. Adequate Se intake has health benefits and reduces mercury (Hg) toxicity, which is important due to its neurotoxicity. This study determined the Se status and redox enzyme, including selenoproteins', activity in pregnant women highly exposed to Hg (between 1 to 54 µg Hg/L blood) via fish consumption. A cross-sectional study enrolling 513 women between the first and third trimester of pregnancy from Madeira, Portugal was conducted, encompassing collection of blood and plasma samples. Samples were analyzed for total Se and Hg levels in whole blood and plasma, and plasma activity of redox-active proteins, such as glutathione peroxidase (GPx), thioredoxin reductase (TrxR) and thioredoxin (Trx). Enzyme activities were related to Se and Hg levels in blood. Se levels in whole blood (65.0 ± 13.1 µg/L) indicated this population had a sub-optimal Se status, which translated to low plasma GPx activity (69.7 ± 28.4 U/L). The activity of TrxR (12.3 ± 5.60 ng/mL) was not affected by the low Se levels. On the other hand, the decrease in Trx activity with an increase in Hg might be a good indicator to prevent fetal susceptibility.

Patterns and Determinants of Essential and Toxic Elements in Chinese Women at Mid-Pregnancy, Late Pregnancy, and Lactation

Maternal status of essential and toxic elements affects the health of the mother, developing fetus, or breastfeeding infant. However, few studies have examined the patterns of these elements and their determinants in pregnant or lactating women. Plasma samples of 1211 healthy mid-pregnant, late pregnant, and lactating women enrolled in coastland, lakeland, and inland areas of China from May–July 2014, were analyzed for concentrations of 15 elements, using inductively coupled plasma mass spectrometry. The adjusted median concentrations of elements varied by physiologic stage and region. Lactating versus pregnant women showed higher concentrations of Zn, Cr, Mo, Ni, Sb, Cd and Pb, but lower concentrations of Cu, I, Al and Hg. In pregnant women, the concentrations of Fe, Zn, I, Mo, Ni, Al, Hg and Cd were higher in mid- versus late-pregnancy. Overall, the highest concentrations were observed in Zn, I, Mn, Al, and Pb in coastland, in Hg in lakeland, and in Fe in inland area. Element concentrations varied by maternal age, pre-pregnancy BMI, education, parity, delivery mode, feeding practice, and intakes of aquatic products and mutton. In conclusion, essential and toxic elements coexisted in pregnant and lactating women, and their concentrations varied by physiologic stages, regions, maternal socio-demographic characteristics and dietary factors.

Serum selenium levels of pre-eclamptic and normal pregnant women in Nigeria: A comparative study

INTRODUCTION

Trace element selenium, an antioxidant, and peroxynitrite scavenger when incorporated into selenoproteins and enzymes reduce oxidative stress which is implicated in the aetiopathogenesis of pre-eclampsia. A paucity of information exists on the serum selenium levels among pre-eclamptic pregnant women in Nigeria, hence the need for this study.

OBJECTIVE

To compare mean serum selenium levels and prevalence of selenium deficiency in preeclamptic pregnant women and their normotensive pregnant controls.

MATERIALS AND METHODS

A comparative case-control study was carried out at the Department of Obstetrics and Gynaecology, Federal Medical Centre, Owerri, Imo state. Fifty-eight preeclamptic and equal normotensive pregnant controls were matched for age groups, gestational age groups, parity groups, and socio-economic status had their serum samples analyzed for selenium level using atomic absorption spectrophotometer (ASS). Data analysis was done using the statistical package for social sciences (SPSS) version 20.0. P-value of < 0.05 was considered to be statistically significant.

RESULT

Mean serum selenium levels of the preeclamptic women(0.67±0.27μmol/l) was significantly (p<0.001) lower than that of the normotensive controls(1.20±0.46μmol/l). Selenium deficiency occurred significantly more in preeclamptic women (33(56.9%) than normotensive women (10(17.2%). Pearson's coefficient analysis showed negative correlation between serum selenium level with severity of systolic blood pressure (Correlation Coefficient (r) = -0.593), diastolic blood pressure(r = -0.519) and severity of preeclampsia(r = -0.598).

CONCLUSION

Serum selenium levels of pre-eclamptic women were significantly lower compared to that of normotensive pregnant controls and selenium deficiency occurred significantly more among the preeclamptic pregnant women compared to the normotensive controls. Selenium level dynamics in pregnancy possibly could play a role in the incidence of pre-eclampsia among pregnant women.

Associations of Internal-Migration Status with Maternal Exposure to Stress, Lead, and Selenium Deficiency Among Pregnant Women in Shanghai, China

Internal migration and urbanization are occurring on a global scale. Although the risk of exposure to stress/lead/low selenium is assumed to be high among migrant pregnant women, population-based evidence is limited. This study aims to explore the association of internal-migration status with maternal exposure to lead, low selenium, and stress among pregnant women. A total of 1931 pregnant women were investigated in 2010. The internal-migration status was grouped based on their hukou (registered residence) and length-of-residency in Shanghai. Maternal blood lead and serum selenium concentrations were assessed. Life event stress and emotional stress were evaluated using "Event-Stress-Scale-for-Pregnant-Women" and "Symptom-Checklist-90-R-Scale" (SCL-90-R), respectively. Logistic regression and general linear models were used to evaluate associations between migration status and lead/stress/low selenium exposure. Compared with the local (with Shanghai hukou and length-of-residency ≥ 5 years), new migrants (without Shanghai hukou and length-of-residency < 2 years) had lower social-economic-status (SES), higher lead, life event and emotional stress, and lower selenium levels. After adjusting for SES, new migrants had higher risks of emotional stress (for interpersonal sensitivity of SCL-90-R, OR = 2.10, 95% CI 1.22-3.64) and low selenium [lg(selenium): beta = - 0.08, 95% CI - 0.11, - 0.05], but no significant risks for life event stress and high lead. Compared with the local, migrant pregnant women in big cities may have emotional stress and low selenium independent of SES, and high lead and life event stress dependent on SES.

The Relationship between the Serum Level of Selenium and Cervical Intraepithelial Neoplasia: A Comparative Study in a Population of Nigerian Women

Objective: To determine the relationship between the serum level of selenium and cervical intraepithelial neoplasia (CIN). Methods: A case controlled study that compared the serum level of selenium in 45 women with CIN (cases) to 45 women (age matched controls) with normal cervical cytology. Socio-demographic data and information on known risk factors for cervical cancer among the sample was compared between both groups using inferential statistics. Results: There was no significant difference in the mean selenium values between the cases and controls [p- 0.076, 95% CI (-15.08 – 0.76)]. However, subgroup analysis showed a statistically significant difference between patients with normal cervical cytology, CIN I, II and III (p= 0.021). In addition, there was also significant difference in the selenium level between women with normal cervical cytology and CIN III (p value = 0.016) with a significant inverse linear trend (p= 0.025). Conclusion: With increasing severity of CIN, a significant reduction in the level of selenium in serum was observed. This reducing value of serum selenium, a surrogate marker for increased oxidative stress, may be important factor for the development of persistent HPV infection and in particular high grade CIN III lesions. This observation requires further research.

Serum Selenium Level in Early Healthy Pregnancy as a Risk Marker of Pregnancy Induced Hypertension

Selenium (Se) is an antioxidant nutrient whose deficiency can influence adverse outcomes of pregnancy. The aim of this study is to determine whether serum Se level in early healthy pregnancy may be a risk marker for pregnancy induced hypertension. We obtained data from our prospective study in which we recruited healthy women in weeks 10–14 of a single pregnancy. In this analysis, we examined 121 women who subsequently developed pregnancy-induced hypertension and matched 363 women who remained normotensive. We measured Se levels (using the ICP-MS technique) in the serum in weeks 10–14 of the pregnancy. The odds ratios of pregnancy-induced hypertension (95% confidence intervals) were calculated using multivariate logistic regression. We found that the mean Se level was lower in the case group compared to the control (57.51 vs. 62.89 μg/L; p = 2.6 × 10⁻¹⁰). Excessive body mass index (BMI) and smoking influenced the estimated odds ratios. In the subgroup of women who had never smoked with normal pre-pregnancy BMI, the adjusted odds ratio (AOR) of pregnancy-induced hypertension was 15.34 (95% CI: 2.73–86.31, p = 0.002) for Se levels in the lowest quartile (≤57.68 µg/L), as compared to the highest quartile (>66.60 µg/L), after adjusting for all the accepted confounders. In the whole cohort, the prognostic value of Se by logistic regression showed that the area under curve (AUC) = 0.814. In our study, one can consider the role of Se as a risk marker of pregnancy-induced hypertension.

Toxics (Pb, Cd) and trace elements (Zn, Cu, Mn) in women during pregnancy and at delivery, South Benin, 2014-2015

During pregnancy, fetal development can be hindered by maternal exposure to toxic elements and abnormal concentrations of trace elements. Few data are available in African countries. Our goal was to assess the body burden of lead (Pb), cadmium (Cd), manganese (Mn), zinc (Zn) and copper (Cu) in pregnant women in Benin. The study was carried out in Sô-Ava district, from November 2015 to April 2016. Sixty women were recruited from the RECIPAL pre-conceptional cohort study. In all women, blood samples were collected during the first trimester of pregnancy. Thirty-two women had additional maternal and cord blood samples collected at delivery. Blood samples were analyzed by inductively coupled plasma mass spectrometry. At delivery, Cd median (IQR) concentration in maternal blood was 0.34 µg/L (0.24-0.46) in this non-smoking population. Pb median (IQR) concentration in maternal blood at delivery was 37.4 µg/L (30.5-52.0), with 31.3% of blood Pb levels above the 50 μg/L threshold. These pregnant women lived in semi-rural lakeside villages. Potential sources of Pb exposure identified during pregnancy were having water supply by drill pump and activities such as smoking fish by the woman and fishing by the household head. At delivery, Zn, Cu, and Mn median (IQR) concentrations in maternal blood were, respectively, 5415 μg/L (4894-5822), 1609 μg/L (1295-1771) and 16.0 μg/L (12.5-20.8). Pb, Cd, Mn and Cu blood concentrations were significantly higher at delivery than during the first trimester of pregnancy. Pb, Cd, Zn and Cu concentrations were significantly lower in cord blood than in maternal blood, contrary to Mn concentration, which was significantly higher in cord blood than in maternal blood at delivery. This exploratory study is the first one performed in Benin, and warns us about exposition of women from Sô-Ava district to Pb and Cd during pregnancy.

Study of the influencing factors of the blood levels of toxic elements in Africans from 16 countries

Africa's economy is growing faster than any other continent and it has been estimated that the middle class in Africa now exceeds 350 million people. This has meant a parallel increase in the importation of consumer goods and in the implementation of communication and information technologies (ICT), but also in the generation of large quantities of e-waste. However, inadequate infrastructure development remains a major constraint to the continent's economic growth and these highly toxic residues are not always adequately managed. Few studies have been conducted to date assessing the possible association between socioeconomic development factors, including e-waste generation, and blood levels of inorganic elements in African population. To disclose the role of geographical, anthropogenic, and socioeconomic development determinants on the blood levels of Ag, Al, As, Be, Cd, Co, Cr, Hg, Ni, Pb, Sb, and V -all of them frequently found in e-waste-, an immigrant population-based study was made including a total of 245 subjects from 16 countries recently arrived to the Canary Islands (Spain). Women presented higher levels of blood elements than men, and Northern Africans (Moroccans) were the most contaminated. People from low-income countries exhibited significantly lower blood levels of inorganic elements than those from middle-income countries. We found a significant association between the use of motor vehicles and the implementation of information and communication technologies (ICT) and the level of contamination. Immigrants from the countries with a high volume of imports of second-hand electronic equipment, telephone and internet use had higher levels of inorganic elements. In general terms, the higher level of economic development the higher the blood levels of inorganic pollutants, suggesting that the economic development of Africa, in parallel to e-waste generation and the existence of informal recycling sites, have directly affected the level of contamination of the population of the continent.

Zinc and copper status in childbearing age Tunisian women: Relation to age, residential area, socioeconomic situation and physiologic characteristics

Plasma zinc and copper status of 1689 non pregnant Tunisian women, aged 20-49 years old, was determined by flame atomic absorption spectrometry. A multiple regression was run to predict plasma trace element concentrations from age, BMI, marital status, menopause, education level, professional activity, economic level and area of living. The mean zinc and copper values were similar to those measured among comparable populations in earlier studies. However, a high prevalence of low plasma zinc and copper concentrations was observed assuming that women at childbearing age are at high risk of zinc and copper deficiencies and specific intervention may be considered. In univariate analysis, the mean values of plasma zinc and copper were associated with sitting areas and professional activity. For only plasma copper levels, there was an increase with BMI and parity, and a decrease with increasing schooling level and economic score. After adjustment for all variables, profession and parity showed a significant relationship between plasma levels copper.

Low serum selenium concentration is associated with preeclampsia in pregnant women from Bangladesh

OBJECTIVES

Preeclampsia is a hypertensive disorder of pregnancy which is one of the leading causes of maternal and perinatal mortality and pre-term delivery, especially in low and middle income countries. Selenium is an important constituent of selenoproteins that act as antioxidant and have several metabolic functions. The present study was conducted to determine serum selenium concentration in preeclampsia patients in order to find out the role of selenium in preeclampsia.

METHODS

This study was conducted as case-control study with 74 preeclampsia patients as cases whose gestation were ≥20 weeks (52 mild and 22 severe patients) and 118 normotensive pregnant women as controls from same gestational period. Detailed patient history was recorded during routine hospital visits. Serum selenium concentration was determined by using atomic absorption spectroscopy. Independent sample t-test and Pearson's correlation test were done for the statistical analysis using the statistical software package SPSS, version 16.

RESULTS

Our study found that mean serum concentration of selenium in preeclampsia patients was significantly lower than that of healthy pregnant women (p<0.05). Further analysis for selenium concentration with disease severity explored that selenium concentration was significantly lower in severe preeclampsia in comparison to mild preeclampsia (p<0.05). We found no significant difference for selenium concentration between rural and urban preeclampsia patients (p>0.05). Pearson's correlation analysis reveals significant negative correlation of selenium with systolic blood pressure (r=-0.419, p=0.001), diastolic blood pressure (r=-0.392, p=0.001), and gestational period (r=-0.218, p=0.001).

CONCLUSION

Our study found that preeclampsia patients have decreased serum selenium concentration than the healthy pregnant women.