Heavy metal contamination in agricultural soils has attracted increasing attention in recent years. In this study, 1999 agricultural soil samples were collected from 11 cities in Zhejiang Province from 2016 to 2020, and the spatial and temporal variation characteristics of 3 of the most important heavy metals, i.e., lead (Pb), cadmium (Cd), and chromium (Cr) were analyzed. The results showed that Cd had a slightly higher sample over-standard rate of 12.06%. Spatial distribution and temporal trends showed that the Pb concentrations overall increased from 2016 to 2020 and mainly accumulated in southern Zhejiang. In addition, multiple exposure routes were evaluated for human health risks. Children are more susceptible to the adverse effects of heavy metals in agricultural soils, and oral ingestion was the major exposure route. Cr poses higher human health risks to humans than Pb and Cd in agricultural soils. Therefore, more rigid environmental monitoring and related soil remediation counter-measures for some sites with high concentrations of heavy metals are necessary to limit the potential threat to human health.

Background/Objectives: Nicotinic acid (NA; niacin) and nicotinamide (NAM) participate in nicotinamide adenine dinucleotide metabolism, but pediatric evidence relating serum concentrations of these vitamers to behavioral-problem scores is limited. Methods: We conducted an exploratory analysis of children assessed in Yiwu, Zhejiang Province, China, with serum NA and NAM concentrations recorded in 2021 and 2025 and caregiver-reported Child Behavior Checklist (CBCL) outcomes in 2025. Vitamin B3 was measured by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Internalizing, externalizing, and total-problem raw scores were the broadband outcomes; seven common raw subscales were exploratory outcomes. Multivariable linear models and three-knot restricted cubic splines (RCSs) were conducted to assess the associations between vitamin B3 and CBCL scores. Benjamini–Hochberg correction and exposure-by-sex interaction tests were used. Results: Pooled associations were compatible with the null after correction. Per interquartile-range (IQR) increase in 2021 NA, boys’ adjusted contrasts were −2.18 (95% CI, −4.22 to −0.13) for internalizing, −3.04 (−5.05 to −1.04) for externalizing, and −5.33 (−9.18 to −1.47) for total problems. In sex-stratified RCS analyses, 2021 NA was associated with externalizing (q-overall = 0.040) and total problems (q-overall = 0.023) in boys, whereas 2025 NA was associated with these outcomes in girls (both q-overall = 0.042). Sex-stratified two-degree-of-freedom RCS models had limited sensitivity for small-to-modest associations. Conclusions: The sex-interaction and sex-stratified RCS patterns for NA are hypothesis-generating and require independent, prespecified replication.

Infertility presents a substantial challenge for women of reproductive age, exerting profound effects on both individual well-being and healthcare systems. Despite its critical role in folate and homocysteine pathways, the influence of methylenetetrahydrofolate reductase (MTHFR) on the success of assisted reproductive techniques (ART) remains insufficiently understood. This knowledge gap impedes the development of personalized therapeutic strategies. Our study seeks to elucidate the relationship between MTHFR and ART outcomes, exploring potential mediators to enhance treatment efficacy. A cohort of 311 women with infertility was recruited for our study. Multivariate linear models were utilized to evaluate the relationship between the MTHFR 677T allele (a missense mutation resulting in an alanine to valine substitution) and the efficacy of ART, including both treatment outcomes and the number of ART cycles required. Sequential mediation analysis was conducted to elucidate the potential mediators influencing ART efficacy. The MTHFR 677T allele carried by infertile women was associated with a 17–51% reduction in ART efficacy ( P < 0.05). This encompassed poorer overall ART outcomes, such as clinical pregnancy and live birth rates, as well as an increased number of ART cycles. Sequential mediation analysis suggested that anti-Müllerian hormone (AMH) and age may act as mediators modulating the impact of the MTHFR 677T allele on ART treatment efficacy. This study has unveiled the intricate connection between MTHFR 677T allele and ART treatment efficacy in infertile women, shedding light on the mediating role of AMH and age.