Plasma zinc levels in Ecuadorian mothers of infants with nonsyndromic cleft lip with or without cleft palate: A case series

Maternal serum zinc concentration and neural tube defects in offspring: a meta-analysis

OBJECTIVE

This study was to assess the relationship between maternal serum zinc concentration and NTDs in offspring by conducting a meta-analysis.

METHODS

We searched Pubmed, Medline and Web of Science for all English studies about the relationship between maternal serum zinc level and NTDs in offspring (published between 1 January 1975 and 1 January 2020). Pooled effect sizes with corresponding 95% CIs were calculated using a random-effect model by Revman 5.3 and Stata 15.1 software.

RESULTS

Eight articles met our selection criteria and a total of 187 cases and 894 controls were included in this meta-analysis. Our results showed that mothers with NTDs infants had lower serum zinc concentration than those with healthy infants (SMD= -0.77, 95%CI [-1.16, -0.37], p = .0001, I ² = 73%).

CONCLUSIONS

Compared with mothers with healthy infants, mothers with NTDs infants have lower serum zinc levels, suggesting that low maternal serum zinc level during pregnancy is probably associated with the risk of NTDs in offspring. But the mechanism of the association remains to be ascertained by large-scale cohort studies.

Metal mining and birth defects: a case-control study in Lubumbashi, Democratic Republic of the Congo

BACKGROUND

Widespread environmental contamination caused by mining of copper and cobalt has led to concerns about the possible association between birth defects and exposure to several toxic metals in southern Katanga, Democratic Republic of the Congo (DRC). We therefore aimed to assess the possible contribution of parental and antenatal exposure to trace metals to the occurrence of visible birth defects among neonates.

METHODS

We did a case-control study between March 1, 2013, and Feb 28, 2015, in Lubumbashi, DRC. We included newborns with visible birth defects (cases) and healthy neonates born in the same maternity ward (controls). Mothers were interviewed about potentially relevant exposures, including their partners' jobs. Various trace metals were measured by inductively coupled plasma mass spectrometry in maternal urine, maternal blood, umbilical cord blood, placental tissue, and surface dust at home. Multivariable logistic regression analyses were done to calculate adjusted odds ratios and their 95% CIs (CI).

FINDINGS

Our study included 138 neonates with visible birth defects (about 0·1% of the 133 662 births in Lubumbashi during the study period) and 108 control neonates. Potential confounders were similarly distributed between cases and controls. Vitamin consumption during pregnancy was associated with a lower risk of birth defects (adjusted odds ratio 0·2, 95% CI 0·1-0·5). Mothers having paid jobs outside the home (2·8, 1·2-6·9) and fathers having mining-related jobs (5·5, 1·2-25·0) were associated with a higher risk of birth defects. We found no associations for trace metal concentrations in biological samples, except for a doubling of manganese (Mn; 1·7, 1·1-2·7) and zinc (Zn; 1·6, 0·9-2·8) in cord blood. In a separate model including placentas, a doubling of Mn at the fetal side of the placenta was associated with an increased risk of birth defects (3·3, 1·2-8·0), as was a doubling of cord blood Zn (5·3, 1·6-16·6).

INTERPRETATION

To our knowledge, this is the first study of the effects of mining-related pollution on newborns in sub-Saharan Africa. Paternal occupational mining exposure was the factor most strongly associated with birth defects. Because neither Mn nor Zn are mined in Lubumbashi, the mechanism of the association between their increased prenatal concentrations and birth defects is unclear.

FUNDING

Flemish Interuniversity Council-University Development Cooperation, The Coalition of the North-South movement in Flanders 11.11.11.

Zinc Adequacy Is Essential for the Maintenance of Optimal Oral Health

Zinc, a metal found in the Earth's crust, is indispensable for human health. In the human body, around 60% of zinc is present in muscles, 30% in bones, and the remaining 10% in skin, hair, pancreas, kidneys and plasma. An adequate zinc balance is essential for the maintenance of skeletal growth, development and function. It is also necessary for basic cellular functions including enzyme activation, cell signaling and energy metabolism. Inadequate zinc status is associated with a wide variety of systemic disorders including cardiovascular impairment, musculoskeletal dysfunctions and oromaxillary diseases. In this article, we briefly discuss the role of zinc deficiency in the genesis of various oromaxillary diseases, and explain why adequate zinc homeostasis is vital for the maintenance of oral and general health.

Levels of uranium and thorium in maternal scalp hair and risk of orofacial clefts in offspring

Uranium and thorium are common radioactive elements that exist in the environment. However, few environmental epidemiological studies have focused on their possible effects on congenital malformations. Here, we explored the association between uranium and thorium concentrations in maternal scalp hair grown from 3 months before to 3 months after conception, namely during the periconceptional period and the risk of orofacial clefts (OFCs) in offspring. Our study included 153 women whose pregnancies were affected by OFCs (cases) and 601 women who delivered infants without birth defects (controls) from four provinces in China. Face-to-face interviews were used to collect sociodemographic characteristics with a structured questionnaire. Concentrations of uranium and thorium in maternal scalp hair grown during the periconceptional period were detected using inductively coupled plasma-mass spectrometry. The risk of OFCs in association with higher concentrations of the two radioactive elements was estimated using odds ratios (ORs) and 95% confidence intervals (CIs) while adjusting for potential confounding factors. The levels of uranium and thorium in maternal hair were in agreement with the published literature. After adjusting for several confounders, the ORs of thorium in the highest, upper, and lower quartile versus the lowest quartile were 2.63 (95% CI, 1.41-4.92), 1.98 (95% CI, 1.03-3.79), and 2.73 (95% CI, 1.46-5.12), respectively. No association was found between levels of uranium and the risk of OFCs. Maternal periconceptional exposure to thorium may be a risk factor for OFCs in offspring.

Zinc Deficiency among Lactating Mothers from a Peri-Urban Community of the Ecuadorian Andean Region: An Initial Approach to the Need of Zinc Supplementation

Zinc is an important mineral for biological and physiological processes. Zinc deficiency (ZD) is one of the most common micronutrient deficiencies worldwide and a crucial determinant of pregnancy outcomes and childhood development. Zinc levels and the zinc supplementation rate among lactating women have not been assessed neither in Ecuador nor in the Andean region. We conducted a pilot study including 64 mothers of infants between eight days to seven months old from a primary care center located in Conocoto, a peri-urban community of Quito, Ecuador. The mothers were interviewed and a fasting blood sample was taken to determine plasma zinc levels. The prevalence of ZD was calculated and compared with the prevalence of ZD among Ecuadorian non-pregnant non-lactating women, and the sample was analysed considering zinc supplementation during pregnancy. The prevalence of ZD among the participants was 81.3% (95% CI: 71.7⁻90.9), higher than the reported among non-pregnant non-lactating women (G² = 18.2; p < 0.05). Zinc supplementation rate was 31.2%. No significant differences were found comparing the groups considering zinc supplementation. The insights obtained from this study encourage extending studies to document zinc levels and its interactions among breastfeeding women in areas with a high prevalence of ZD in order to determine the need of zinc supplementation.