Cadmium Body Burden and Gestational Diabetes Mellitus: A Prospective Study

Urinary concentrations of environmental metals and associating factors in pregnant women

Pregnant women, a vulnerable population, can be exposed to a variety of environmental metals that may adversely affect their health at elevated concentrations. Moreover, environmental exposure and risk disparities are associated with several factors such as sociodemographic characteristics, pregnancy complications, and nutritional supplementation indicators. Our aim was to investigate whether and how the urinary metal concentrations vary according to these factors in a large pregnancy and birth cohort. Urinary levels of seven metals including manganese, zinc, selenium, arsenic, cadmium, thallium, and lead were assessed in 7359 participants across Wuhan City in China. In all, 7359 urine samples from the third trimester were analyzed and 15 sociodemographic characteristics, pregnancy complications, and nutritional supplementation indicators were assessed: maternal age, household income, multivitamin supplements during pregnancy, etc. Concentrations of Zn, As, and Cd were detected in all urine samples; Mn, Se, Tl, and Pb were detected in 95.3%, 99.8%, 99.8%, and 99.9% urine samples, respectively. The geometric mean (GM) of creatinine-adjusted urinary Mn, Zn, Se, As, Cd, Tl, and Pb concentrations were 1.42, 505.44, 18.24, 30.49, 0.64, 0.55, and 3.69 μg/g. Factors that associated with environmental metals concentration were as follows: (1) Urinary Zn and Cd concentrations increased with maternal age. (2) Pregnant women with higher education had lower Cd concentrations. (3) Pregnant women with folic acid supplementation had lower Mn and with multivitamin supplementation had higher Se and lower Tl. Our results demonstrated that the maternal age, education level, folic acid supplementation, and multivitamin supplementation were significantly associated with environmental metal concentrations. Furthermore, studies are recommended to explore the influence of diet on biological metals concentrations in more detail.

Parabens exposure in early pregnancy and gestational diabetes mellitus

BACKGROUND

Widespread exposure to parabens has been a concern, especially among pregnant women. Only one study reported that parabens are associated with glucose levels among pregnant women. However, studies on parabens exposure and gestational diabetes mellitus (GDM) are lacking.

OBJECTIVES

This study investigated whether exposure to parabens in early pregnancy is related to GDM.

METHODS

We conducted a prospective study of 1087 pregnant women from a single tertiary medical center between 2014 and 2015 in Wuhan, China. Parabens [methyl paraben (MeP), ethylparaben (EtP), propylparaben (PrP), butylparaben (BuP), and benzylparaben (BzP)] concentrations were measured in spot urine samples collected between 8 and 16 gestational weeks. GDM was diagnosed according to the International Association of Diabetes and Pregnancy Study Groups Consensus Panel (IADPSG) recommendations. We used the Poisson regression with a robust error variance with generalized estimating equations (GEE) estimation analyses to evaluate associations between parabens exposure and GDM risk.

RESULTS

A total of 103 (9.5%) women were diagnosed with GDM. We evaluated the associations of GDM risk with urinary MeP, EtP, and PrP (detection rate: >90%), but not with BuP and BzP due to the relatively low detection rate (<50%). After adjustment for potential confounders, urinary EtP was associated with GDM. The risk ratios (RRs) = 1.12 (95% CI: 0.63, 2.01) for the second quartile, RRs = 1.11 (95% CI: 0.64, 1.93) for the third quartile, and RRs = 1.70 (95% CI: 1.02, 2.82) for the highest quartile, compared with the lowest quartile. There was no evidence of associations between urinary MeP or PrP and GDM.

CONCLUSIONS

To the best of our knowledge, this is the first report of an association between urinary paraben levels in early pregnancy and GDM. Our findings suggest that exposure to EtP may increase the risk of GDM.

Antimony in urine during early pregnancy correlates with increased risk of gestational diabetes mellitus: A prospective cohort study

BACKGROUND

Antimony (Sb) has been associated with type 2 diabetes in previous studies. However, the role of Sb in the incidence of Gestational diabetes mellitus (GDM) remains unclear.

OBJECTIVES

We investigated the association between Sb exposure during early pregnancy and the risk of GDM.

METHODS

We performed a prospective study of 2093 pregnant women from the Tongji Maternal and Child Health Cohort (TMCHC). Sb concentrations were measured in urine samples during early pregnancy by ICP-MS. The association between urinary Sb concentration and GDM incidence was assessed using robust Poisson regression model after adjustment for confounders.

RESULTS

The 95th percentile value of creatinine-corrected Sb (CC-Sb) concentration in the urine of all pregnant women was 1.33 μg/g. The CC-Sb concentrations were significantly higher in women with GDM than those without GDM (median value: 0.49 μg/g vs. 0.38 μg/g, p = 0.001). After adjustment for potential confounders, for each one natural logarithmic unit increase in Sb concentration, there was 29% [adjusted relative risk (RR) = 1.29; 95% confidence interval (CI): 1.06, 1.57] increase in the risk of GDM. Women in the highest tertile for CC-Sb had a 1.92-fold (95% CI: 1.42, 2.60) higher risk of GDM compared with women in the lowest tertile (p-value for trend <0.001).

CONCLUSION

To our knowledge, this is the first research of an association between urinary Sb levels during pregnancy and GDM. Our study suggests that pregnant women with higher Sb exposure levels may have a higher risk of GDM and this association remains consistent even after stratification.

Simultaneous determination of amino acids, purines and derivatives in serum by ultrahigh-performance liquid chromatography/tandem mass spectrometry

RATIONALE

Amino acids, purines and derivatives play a key role in physiological and pathological processes, such as the development of gestational diabetes mellitus. However, little literature has reported the simultaneous quantification of amino acids and purines. Therefore, a reliable and robust method for the determination of amino acids and purines is necessary.

METHODS

A rapid and simple method based on ultrahigh-performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) was developed to determine the concentrations of twenty amino acids or derivatives and three purines or derivatives in serum.

RESULTS

The method was validated for linearity of calibration curve, limit of detection, limit of quantification, inter-day and intra-day precision, recovery, stability and matrix effect. The correlation coefficients of calibration curves were higher than 0.993 except for isoleucine. The recoveries ranged from 78.4% to 128.0% for three different concentrations of the spiked analytes. The matrix effect value ranged from -7.3% to 9.2%.

CONCLUSIONS

A rapid and simple UHPLC/MS/MS method for the simultaneous measurement of amino acids, purines and derivatives in serum samples was developed. The method was successfully applied to determine and compare the concentrations of analytes between gestational diabetes mellitus samples and controls.

Exposure to Bisphenol a Substitutes and Gestational Diabetes Mellitus: A Prospective Cohort Study in China

Background: The association of bisphenol A (BPA) and gestational diabetes mellitus (GDM) has been investigated in only a small number of studies, and research on the associations between BPA substitutes and GDM is scarce. Objective: We aimed to investigate the associations of four bisphenols [bisphenol A (BPA), bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF)] levels in urine sample with the risk of gestational diabetes mellitus (GDM) and plasma glucose levels. Methods: A total of 1,841 pregnant women from a cohort study were recruited at their first prenatal examination between 2013 and 2015 in Wuhan, China. Concentrations of four bisphenols (BPA, BPS, BPF, BPAF) were measured in first-trimester urine samples using Ultra-high performance liquid chromatography system coupled to a Triple Quadrupole mass spectrometer (UHPLC-TQMS). An oral glucose tolerance test (OGTT) was performed at 24-28 gestational weeks and GDM was diagnosed post hoc using International Association of Diabetes and Pregnancy Study Groups criteria. We used multivariable logistic regression models to examine the associations of urinary bisphenols with the risk of GDM, and multiple linear regression models to determine the associations between bisphenols exposure and plasma glucose levels. Results: Urinary BPAF was associated with increased odds of GDM among women with normal pre-pregnancy BMI [adjusted odds ratio (aOR) = 1.70 (95% CI: 1.08, 2.67) for the highest group compared to the lowest group], and the association remained significant after additional adjustment for other bisphenols [aOR = 1.68 (95% CI: 1.03, 2.72)]. No significant associations were observed for other bisphenols and GDM. Consistent with the result of GDM, women in the highest BPAF category had a mean of 0.05 mmol/L (95% CI: 0.01, 0.09) higher fasting plasma glucose (FPG) levels than women in the lowest category. For BPA and plasma glucose, non-linear associations were observed between urinary BPA and FPG and the sum of the PG z-score among women who were overweight (p for non-linear association < 0.05). We also found that the per-unit increase in natural log transformed specific gravity adjusted BPS [ln (SG-adj BPS)] was associated with a 0.03 mmol/L (95% CI: 0.01, 0.04) increase in FPG levels and the associations might be modified by fetal sex (p for interaction < 0.05). Among women with female fetus, a per-unit increase in ln (SG-adj BPS) was associated with a 0.04 mmol/L (95% CI: 0.02, 0.06) increase in FPG, a 0.11 mmol/L (95% CI: 0.04, 0.17) increase in 1 h-PG and a 0.19 mmol/L (95% CI: 0.08, 0.30) increase in the sum of PG z-score. Conclusions: Our results provide evidence that BPAF and BPS might be potential risk factors of GDM, which require to be studied further.

Association between maternal urinary speciated arsenic concentrations and gestational diabetes in a cohort of Canadian women

BACKGROUND

Epidemiological and toxicological evidence suggests that maternal total arsenic (As) levels are associated with an elevated risk of gestational diabetes (GDM). Uncertainty remains regarding the metabolic toxicity of specific arsenic species, comprised of both organic and inorganic sources of arsenic exposure.

OBJECTIVES

We assessed associations between speciated As and GDM using data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study.

METHODS

Concentrations of speciated As [(inorganic (trivalent, pentavalent)), methylated arsenic species metabolites (monomethylarsonic acid (MMA), dimethylarsinic acid (DMA)), and organic (arsenobetaine)] were measured in first trimester maternal urine samples. GDM cases were identified in accordance with Canadian guidelines. Multivariable regression models were used to estimate associations between speciated As and GDM, evaluate potential interaction between speciated As exposures, and assess fetal sex-specific findings.

RESULTS

Among 1243 women who had a live, singleton birth and no previous history of diabetes, 4% met the diagnostic criteria for GDM. Our analyses focused on DMA and arsenobetaine as these were the subtypes with detectable concentrations in at least 40% of samples. Compared to women in the lowest tertile of DMA (<1.49 μg As/L), women with concentrations exceeding 3.52 μg As/L (3rd tertile) experienced an increased risk of GDM (aOR = 3.86; 95% CI: 1.18, 12.57) (p-value for trend across tertiles = 0.04). When restricted to women carrying male infants, the magnitude of this association increased (aOR 3rd tertile = 4.71; 95% CI: 1.05, 21.10).

CONCLUSIONS

These results suggest a positive relation between DMA and GDM; potential differences in risk by fetal sex requires further investigation.