Association of blood cadmium and lead levels with self-reported reproductive lifespan and pregnancy loss: The national health and nutrition examination survey 1999-2018

Association of coexposure to perfluoroalkyl and polyfluoroalkyl compounds and heavy metals with pregnancy loss and reproductive lifespan: The mediating role of cholesterol

Previous studies have demonstrated the toxic effects of per- and polyfluoroalkyl substances (PFASs) and heavy metals on the reproductive system. However, the interactions and combined effects of these substances remain unexplored. This study utilizes data from the National Health and Nutrition Examination Survey to investigate the associations between coexposure to four types of PFASs, lead (Pb), mercury (Hg) and self-reported pregnancy loss and reproductive lifespan in females. Genes associated with these substances and abortion were identified via the Comparative Toxicogenomics Database. The results revealed that Ln-PFOA (IRR=1.88, 95 % CI=1.42-2.50, Ln--: log transformed), Ln-PFOS (IRR=1.58, 95 % CI=1.12-2.22), Ln-PFHxS (IRR=1.99, 95 % CI=1.57-2.52), and Ln-Hg (IRR=1.92, 95 % CI=1.41-2.43) were positively associated with the risk of pregnancy loss. Ln-PFOA (β=1.27, 95 % CI=0.28-2.27), Ln-PFOS (β=1.01, 95 % CI=0.39-1.63), Ln-PFHxS (β=0.71, 95 % CI=0.12-1.63), Ln-PFNA (β=1.15, 95 % CI=0.23-2.08), Ln-Pb (β=3.87, 95 % CI=2.58-5.15), and Ln-Hg (β=1.01, 95 % CI=0.39-1.64) exposures were positively associated with reproductive lifespan. The mixed and overall effects of coexposure to PFASs and heavy metals were positively correlated with the risk of pregnancy loss and reproductive lifespan. Cholesterol partially mediated the association with the risk of pregnancy loss, whereas delay in menopause fully mediated the association with reproductive lifespan. Significant additive interactions were observed between PFOA and Pb and between PFOS, PFHxS, PFNA and Hg at high levels of coexposure. Thirty-nine overlapping genes associated with abortion were identified for these substances, and further analyses revealed that these genes significantly interact and may contribute to abortion through oxidative stress.

Associations of urinary heavy metals with age at menarche, age at menopause, and reproductive lifespan: A cross-sectional study in U.S. women

Female reproductive timing and lifespan, with a close relation to long-term health outcomes, have been altered in U.S. women over the past decades. However, epidemiologic evidence of the potential causes was lacking. On the basis of 1981 naturally postmenopausal women from the National Health and Nutrition Examination Survey 1999-2020, this study aimed to investigate the associations of urinary heavy metals with age at menarche, age at menopause, and reproductive lifespan. Multivariate generalized linear regression and addictive models were used for single metal exposure analysis, and weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models were employed for mixed exposures. In the fully adjusted model, higher urinary antimony concentration was associated with earlier age at menarche of 0.137 years, while higher concentrations of cadmium, cesium, lead, antimony, and thallium were associated with delayed age at menopause of 0.396-0.687 years. Additionally, urinary barium, cesium, lead, antimony, and thallium levels were associated with longer reproductive lifespan ranging between 0.277 and 0.713 years. Both WQS and BKMR models showed significantly positive associations of metal mixtures with age at menopause (β: 0.667, 95 % CI: 0.120-1.213) and reproductive lifespan (β: 0.686, 95 % CI: 0.092-1.280), with cadmium and lead identified as principal contributors. In conclusion, heavy metal exposures were associated with reproductive timing and lifespan of U.S. women, highlighting the need for further prevention and intervention strategies.

Associations between Non-Essential Trace Elements in Women's Biofluids and IVF Outcomes in Euploid Single-Embryo Transfer Cycles

Previous studies have found inconsistent associations between heavy metals and metalloids (cadmium, lead, mercury, and arsenic), and reproductive outcomes. The biofluid concentrations of ten non-essential trace elements (Hg, Pb, As, Ba, Sr, Rb, Cs, Sn, Ni, and Co) were evaluated in 51 Spanish women undergoing ICSI, PGT-A, and SET/FET. Nine out of ten non-essential elements were detectable in follicular fluid, whole blood, and urine collected the day of vaginal oocyte retrieval (VOR) and the day of embryo transfer and then analyzed by ICP-MS or Tricell DMA-80 for mercury. Elevated mercury and strontium concentrations in follicular fluid were associated with poor ovarian response and preimplantation outcomes. Worst preimplantation outcomes were also identified in women with elevated whole-blood strontium or mercury, urinary arsenic, barium, and tin the day of VOR. High concentrations of urinary rubidium on VOR day were linked with enhanced fertilization and blastocyst development. Excessive titanium in whole blood was associated with lower odds of implantation, clinical pregnancy, and achieving a live birth in a given IVF cycle. Excessive urinary arsenic on the day of embryo transfer was associated with lower odds of live birth. Although these preliminary results need to be confirmed in larger populations, distinguishing organic and inorganic element forms, our findings show that some non-essential elements have a detrimental impact on human IVF outcomes.

Urinary cadmium levels in China (1982-2021): Regional trends and influential factors

Despite the significant threat of cadmium exposure in China, a national-level assessment has been conspicuously absent. This study bridges this critical gap by collecting, geospatial analyzing and multivariable regression analyzing published studies on urinary cadmium levels in Chinese from 1982 to 2021. Our research reveals a notable decline trend in cadmium exposure among Chinese populations. However, this trend varies by region, age and gender group, higher levels are seen in the South (1.04 μg/g cr) compared to the North (0.48 μg/g cr), and in adults (1.08 μg/g cr) relative to children (0.33 μg/g cr), with higher levels being more pronounced in females (6.17 μg/g cr). Urinary cadmium is significantly correlated with rice consumption (P < 0.001), while mining activities have been identified as the dominant factor for cadmium exposure in most regions of China, a trend that is evident both in past decades and is expected to continue into the next decade. These findings underscore the need for region-specific environmental and public health strategies, designed to effectively address the distinct cadmium exposure risks in various regions and among different population groups, thus enhancing protection against the adverse effects of cadmium.

Potential pathological mechanisms and pharmacological interventions for cadmium-induced miscarriage

The prevalence of cadmium (Cd) contamination has emerged as a significant global concern. Exposure to Cd during pregnancy is associated with adverse pregnancy outcomes, including miscarriage. However, there is currently a lack of comprehensive summaries on Cd-induced miscarriage. Therefore, it is imperative to further strengthen research into in vivo studies, clinical status, pathological mechanisms, and pharmacological interventions for Cd-induced miscarriage. This study systematically presents the current knowledge on animal models and clinical trials investigating Cd exposure-induced miscarriage. The underlying mechanisms involving oxidative stress, inflammation, endocrine disruption, and placental dysfunction caused by Cd-induced miscarriage are also extensively discussed. Additionally, potential drug interventions such as melatonin, vitamin C, and vitamin E are highlighted for their pharmacological role in mitigating adverse pregnancy outcomes induced by Cd.

The association of female reproductive factors with risk of metabolic syndrome in women from NHANES 1999-2018

BACKGROUND

Female reproductive factors such as age at first birth (AFB), age at last birth (ALB), number of pregnancies and live births play an essential role in women's health. However, few epidemiological studies have evaluated the association between female reproductive factors and metabolic syndrome (MetS). We therefore conducted a cross-sectional study to investigate the association between MetS risk and female reproductive factors.

METHODS

We investigated the relationship between AFB, ALB, number of pregnancies and live births and the incidence of MetS using publicly available data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Weighted multivariable logistic regression analysis, restricted cubic spline (RCS) model, and subgroup analysis were used to evaluate the association between AFB and ALB and the risk of MetS in women. In addition, the relationship between the number of pregnancies, live births and MetS risk was also explored.

RESULTS

A total of 15,404 women were included in the study, and 5,983 (38.8%) had MetS. RCS models showed an N-shaped relationship between AFB and MetS risk, whereas ALB, number of pregnancies, and live births were linearly associated with MetS. Weighted multivariable logistic regression analysis showed that the number of live births was associated with MetS risk, with ORs of 1.18 (95% CI: 1.04, 1.35) for women with ≥ 5 deliveries compared to women with ≤ 2 births.

CONCLUSIONS

AFB was associated with the risk of MetS in an N-shaped curve in women. In addition, women with high live births have a higher incidence of MetS.