Maternal serum zinc level is associated with risk of preeclampsia: A systematic review and meta-analysis

Exploring the Complex Interplay of Trace Elements and Their Association with the Risk of Development of Pre-eclampsia in Pregnancy: a Case-Control

Pre-eclampsia, a hypertensive disorder occurring during pregnancy, poses significant risks to maternal and fetal health worldwide. Despite extensive research, the precise cause of pre-eclampsia remains unknown. Recent studies have indicated that trace elements, essential minerals crucial for various biological processes, might be significant factors in the development of pre-eclampsia. This study examines the intricate relationship between trace elements (magnesium, copper, zinc, calcium, phosphorus, and iron) and the severity of pre-eclampsia. The study involves a total of 150 participants, categorized into three distinct groups: 50 individuals with mild pre-eclampsia, 50 with severe pre-eclampsia, and 50 healthy pregnant controls. Specifically, out of the 100 pre-eclampsia cases, 5 were identified as early-onset and 95 as late-onset. Participants were recruited from a tertiary care hospital based on stringent inclusion and exclusion criteria. All the trace elements were quantitatively measured by direct colorimetric method using the Beckman Coulter AU480 analyzer system (Beckman Coulter, USA). Pre-eclampsia cases exhibited a significantly lowered level of magnesium (2.02 mg/dL), zinc (57.62 mg/dL), calcium (8.02 mg/dL), and phosphorus (3.93 mg/dL). These levels were approximately 14.4%, 20.2%, 21.1%, and 22.6% lower when compared to healthy pregnant women. Conversely, copper (151.67 mg/dL) and iron (53 μg/dL) levels were significantly elevated in pre-eclampsia cases. Age emerged as a significant risk factor, correlating with heightened pre-eclampsia susceptibility. Magnesium showed a protective effect, correlating negatively with age and positively with gestational age. The complex relationships between trace elements, age, and pre-eclampsia underline the need for personalized interventions, potentially including magnesium supplementation, in high-risk pregnancies.

Genetically predicted circulating concentrations of micronutrients and risk of hypertensive disorders of pregnancy: a Mendelian randomization study

PURPOSE

Epidemiological studies examining the association between circulating micronutrients and the risk of hypertensive disorders during pregnancy (HDP) have produced inconsistent results. Therefore, we conducted a Mendelian randomization (MR) analysis to evaluate the potential causal relationship between micronutrients and HDP.

METHODS

Nine micronutrients (beta-carotene, vitamin B6, vitamin B12, calcium, zinc, selenium, copper, folate, and phosphorus) were selected as the exposure factors. Summary data for gestational hypertension (14,727 cases and 196,143 controls) and preeclampsia/eclampsia (7212 cases and 174,266 controls) were extracted from the FinnGen consortium. The MR analysis employed the inverse variance weighted method and conducted a range of sensitivity analyses.

RESULTS

The inverse variance weighted method indicated no significant causal relationship between nine genetically predicted micronutrient concentrations and gestational hypertension, as well as preeclampsia/eclampsia. Sensitivity analyses suggested the absence of pleiotropy.

CONCLUSION

There is no strong evidence to support the causation between circulating micronutrients and hypertensive disorder during pregnancy.

Association of Blood Manganese and Preeclampsia: A Systematic Review and Meta-analysis

A systematic review and meta-analysis was performed to comprehensively evaluate the association between manganese (Mn) level and preeclampsia (PE) during pregnancy. Relevant observational studies were retrieved by searching Medline, Web of Science, Embase, and Cochrane Library from database inception to May 25, 2023. Pooling results was performed using a random-effects model incorporating heterogeneity. This meta-analysis incorporated 18 observational studies, which included 1113 women with PE and 5480 normotensive pregnant women. Pooled results showed that compared to normotensive control, women with PE had significantly lower blood Mn concentration (standardized mean difference: -0.36, 95% confidence interval: -0.50 to -0.22, p < 0.001; I2 = 67%). Subgroup analysis showed that the results were not significantly affected by study country (African, Asian, or Western), timing of blood sampling (before, at, or after the diagnosis of PE), mean blood Mn level of controls, or numbers of confounding factors adjusted (p for subgroup analysis all > 0.05), while methods for measuring blood Mn levels might affect the results (p for subgroup difference < 0.001). Finally, pooled results of three studies showed that a high level of blood Mn was related to a low risk of PE with blood Mn analyzed in continuous (risk ratio [RR]: 0.71, 95% CI: 0.59 to 0.85, p < 0.001; I2 = 0%) and categorized variables (RR: 0.50, 95% CI: 0.30 to 0.82, p = 0.006; I2 = 32%). In conclusion, a low blood level of Mn may be associated with PE in pregnant women.

Oxidative Stress in Pregnancy

Recent years have seen an increased interest in the role of oxidative stress (OS) in pregnancy. Pregnancy inherently heightens susceptibility to OS, a condition fueled by a systemic inflammatory response that culminates in an elevated presence of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the circulatory system. The amplified OS in pregnancy can trigger a series of detrimental outcomes such as underdevelopment, abnormal placental function, and a host of pregnancy complications, including pre-eclampsia, embryonic resorption, recurrent pregnancy loss, fetal developmental anomalies, intrauterine growth restriction, and, in extreme instances, fetal death. The body's response to mitigate the uncontrolled increase in RNS/ROS levels requires trace elements that take part in non-enzymatic and enzymatic defense processes, namely, copper (Cu), zinc (Zn), manganese (Mn), and selenium (Se). Determination of ROS concentrations poses a challenge due to their short half-lives, prompting the use of marker proteins, including malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), and glutathione (GSH). These markers, indicative of oxidative stress intensity, can offer indirect assessments of pregnancy complications. Given the limitations of conducting experimental studies on pregnant women, animal models serve as valuable substitutes for in-depth research. This review of such models delves into the mechanism of OS in pregnancy and underscores the pivotal role of OS markers in their evaluation.

Micronutrients in early life and offspring metabolic health programming: a promising target for preventing non-communicable diseases

Chronic non-communicable diseases are the leading cause of morbidity and mortality worldwide. Developing and implementing effective preventive strategies is the best way to ensure the overall metabolic health status of the population and to counter the global burden of non-communicable diseases. Predisposition to obesity and other non-communicable diseases is due to a combination of genetic and environmental factors throughout life, but the early environment, particularly the environment during the fetal period and the early years of life, is crucial in determining metabolic health, hence the concept of 'fetal programming'. The origins of this causal link between environmental factors and disease lie in epigenetic mechanisms. Among the environmental factors, diet plays a crucial role in this process. Substantial evidence documented the key role of macronutrients in the programming of metabolic diseases early in life. Recently, the effect of maternal micronutrient intake on offspring metabolic health in later life emerged. The purpose of this narrative review is to bring to light available evidence in the literature on the effect of maternal micronutrient status on offspring metabolic health and underlying epigenetic mechanisms that drive this link to highlight its potential role in the prevention of non-communicable diseases.

Essential Trace Elements Status in Portuguese Pregnant Women and Their Association with Maternal and Neonatal Outcomes: A Prospective Study from the IoMum Cohort

Cobalt (Co), copper (Cu), manganese (Mn), molybdenum (Mo), and zinc (Zn) are essential trace elements (ETEs) and important cofactors for intermediary metabolism or redox balance. These ETEs are crucial during pregnancy, their role on specific pregnancy outcomes is largely unknown. This prospective study (#NCT04010708) aimed to assess urinary levels of these ETEs in pregnancy and to evaluate their association with pregnancy outcomes. First trimester pregnant women of Porto and Lisbon provided a random spot urine sample, and sociodemographic and lifestyle data. Clinical data were obtained from clinical records. Urinary ETEs were quantified by inductively coupled plasma mass spectrometry (ICP-MS). A total of 635 mother:child pairs were included. Having urinary Zn levels above the 50th percentile (P50) was an independent risk factor for pre-eclampsia (PE) (aOR [95% CI]: 5.350 [1.044-27.423], p = 0.044). Urinary Zn levels above the P50 decreased the risk of small for gestational age (SGA) birth head circumference (aOR [95% CI]: 0.315 [0.113-0.883], p = 0.028), but it increased the risk SGA length (aOR [95% CI]: 2.531 [1.057-6.062], p = 0.037). This study may provide valuable information for public health policies related to prenatal nutrition, while informing future efforts to de-fine urinary reference intervals for ETEs in pregnant women.

An evidence review and nutritional conceptual framework for pre-eclampsia prevention

Pre-eclampsia is a serious complication of pregnancy, and maternal nutritional factors may play protective roles or exacerbate risk. The tendency to focus on single nutrients as a risk factor obscures the complexity of possible interactions, which may be important given the complex nature of pre-eclampsia. An evidence review was conducted to compile definite, probable, possible and indirect nutritional determinants of pre-eclampsia to map a nutritional conceptual framework for pre-eclampsia prevention. Determinants of pre-eclampsia were first compiled through an initial consultation with experts. Second, an expanded literature review was conducted to confirm associations, elicit additional indicators and evaluate evidence. The strength of association was evaluated as definite relative risk (RR) < 0·40 or ≥3·00, probable RR 0·40-0·69 or 1·50-2·99, possible RR 0·70-0·89 or 1·10-1·49 or not discernible RR 0·90-1·09. The quality of evidence was evaluated using Grading of Recommendations, Assessment, Development and Evaluation. Twenty-five nutritional factors were reported in two umbrella reviews and twenty-two meta-analyses. Of these, fourteen were significantly associated with pre-eclampsia incidence. Higher serum Fe emerged as a definite nutritional risk factors for pre-eclampsia incidence across populations, while low serum Zn was a risk factor in Asia and Africa. Maternal vitamin D deficiency was a probable risk factor and Ca and/or vitamin D supplementation were probable protective nutritional factors. Healthy maternal dietary patterns were possibly associated with lower risk of developing pre-eclampsia. Potential indirect pathways of maternal nutritional factors and pre-eclampsia may exist through obesity, maternal anaemia and gestational diabetes mellitus. Research gaps remain on the influence of household capacities and socio-cultural, economic and political contexts, as well as interactions with medical conditions.

Metal Body Burden as Cardiovascular Risk Factor in Adults with Metabolic Syndrome and Overweight-Obesity Analysed with an Artificial Neural Network: The Role of Hair Mineralograms

In determining the so-called "body burden", hair has been widely accepted for assessing toxic element exposure. However, its role in assessing essential elements is controversial. This study investigates the possible relationship between hair minerals, metabolic syndrome (MetS) and cardiovascular (CV) risk in non-occupationally exposed subjects with overweight-obesity. Ninety-five voluntary participants (aged 51 ± 12) were recruited in Northern Italy. Hair samples were collected and analysed via inductively coupled plasma mass spectrometry; the total toxicity index (TI) was calculated as well. To evaluate cardiovascular risk factors in the presence or absence of MetS, the following factors were considered via the innovative artificial neural network (ANN) method Auto-CM: hair mineralograms (31 elements) and 25 variables including blood pressure, anthropometric parameters, insulin resistance and biochemical serum markers assessing inflammation. The Framingham risk score, fatty liver index (FLI), visceral adiposity index and CV risk scores were also taken into consideration. As shown by the semantic map, which was subsequently confirmed by an activation and competition system (ACS), obesity parameters are strictly associated with CV risk factors, TI and inflammation; meanwhile, the single mineral elements seem to be unimportant. Data obtained via ANN demonstrate that MetS may be at least partly mediated by altered mineral levels also in the presence of obesity and that waist circumference is a crucial point to be monitored rather than BMI alone. Furthermore, the mineral body burden is one of the important factors for CV risk.

Analysis of serum calcium, sodium, potassium, zinc, and iron in patients with pre-eclampsia in Bangladesh: A case-control study

Background and Aims

Pre-eclampsia is a particular type of pregnancy condition. Although the primary etiology of pre-eclampsia is unclear, it hypothesizes that the alteration of trace elements and macro-minerals may play a crucial function in the pathogenesis of Pre-eclampsia. Therefore, our research sought to ascertain the serum level of trace elements (zinc, iron) and macro-minerals (sodium, calcium, potassium) and their possible association with pre-eclampsia.

Methods

The present study was conducted with 74 pre-eclampsia pregnant women (case) and 118 pregnant women having normal blood pressure (controls). Atomic Absorption Spectroscopy determined the serum level of trace components and electrolytes.

Results

The researchers discovered notable differences in maternal age, gestational period, body mass index, systolic and diastolic blood pressure, hemoglobin, and creatinine level. Results of serum analysis revealed that calcium (52.06 ± 3.71 mg/L vs. 65.93 ± 2.57 mg/L, p < 0.05) and potassium (63.44 ± 5.33 mg/L vs. 102.54 ± 4.25 mg/L, p < 0.001) concentrations were substantially lower in the patient group than in control. Serum zinc (0.34 ± 0.02 mg/L vs. 0.52 ± 0.02 mg/L, p < 0.001) and iron (0.38 ± 0.03 mg/L vs. 0.46 ± 0.02 mg/L, p < 0.05) concentration were also considerably decreased in pre-eclampsia participants compared with a pregnant normotensive group. Pearson's correlation research results in the patient group revealed a connection between trace elements or macro minerals. In addition, the systolic blood pressure was positively correlated with sodium (r = 0.392, p < 0.01) and negatively correlated with potassium (r = -0.257, p < 0.05) in the control group.

Conclusions

This study concludes that calcium, potassium, iron, and zinc levels were lower, whereas sodium levels were higher in Bangladeshi pre-eclampsia patients compared to controls. These findings with Pearson's correlation and the inter-element relationship between the patient and a control subject results can act as critical indication factors for patients with pre-eclampsia in Bangladesh and, as a result, may require a higher intake of calcium, potassium, iron, and zinc for effective therapeutic intervention and reduce the intake of sodium.

A global perspective of correlation between maternal blood lead levels and risks of preeclampsia: An updated systematic review and meta-analysis

Background

Preeclampsia (PE) is a specific hypertensive disorder in pregnancy. Lead (Pb) is a heavy metal that affects women's reproductive health. However, it is unclear whether lead exposure during can predispose maternal risk of developing preeclampsia. This systematic review and meta-analysis study aimed to explore the association.

Methods

We searched studies from three databases (PubMed, Web of Science, Embase). Only case-control, cross-sectional, and cohort studies reporting maternal blood lead levels (BLL) and PE were included from database inception to 31st July 2022. Pregnant women with blood lead levels measured were eligible. Those healthy pregnant women who did not develop preeclampsia were assessed as comparators. Letters, comments, case reports, and reviews were excluded. Newcastle-Ottawa Scale (NOS) and its adaptive form were applied for assessment. The random-effects method (REM) was applied to calculate the standardized mean difference (SMD) with a 95% confidence interval (CI). Stata 16.0 and RevMan 5.3 were the software used for data extraction and analysis.

Results

25 studies out of 1,808 articles made the finalist for systematic reviews, of which 21 underwent further quantity analysis. A total of 1,533 preeclamptic women and 10,998 healthy pregnant controls were included in the meta-analysis. The overall result revealed that maternal lead exposure was significantly higher in women with preeclampsia (SMD: 1.06, 95% CI 0.69, 1.43); (I ² = 96.40%; P = 0.000).

Conclusion

This study demonstrates that maternal lead exposure is associated with preeclampsia during pregnancy. The association is present even in low blood lead levels. The conclusion should be taken seriously and women should avoid unexpected exposure to a lead-containing environment as much as possible.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=347220, identifier: CRD42022347220.