Prenatal exposure to phthalates with preterm birth and gestational age: A systematic review and meta-analysis.

Phthalates are non-persistent chemicals used in products of daily necessities. The evidence on the relationship of prenatal phthalates exposure and preterm birth remain uncertain and dimed. We Searched Cochrane, EMBASE, PubMed and Qvid Medline and selected studies according to a priori defined inclusion criteria. A total of 20 relevant studies published before March 31, 2020, were included. The main methods to detect heterogeneity and publication bias of included studies were the Q-statistic and Begg's test. Overall summary estimates indicated positive association of prenatal exposure to di(2-ethylhexyl) phthalate [number of studies (n) = 11, odds ratio (OR) = 1.1; 95% confidence interval (CI): 0.89, 1.4], diethyl phthalate [n = 11, OR = 1.1; 95% CI: 0.92, 1.3], dibutyl phthalate [n = 10, OR = 1.1; 95% CI: 0.77, 1.4], butyl benzyl phthalate [n = 10, OR = 1.0; 95% CI: 0.91, 1.2], diisobutyl phthalate [n = 9, OR = 1.1; 95% CI: 0.92, 1.3], diisononyl phthalate [n = 4, OR = 1.1; 95% CI: 0.85, 1.3], and phthalates were negatively associated with gestational age except di(2-ethylhexyl) phthalate and diisononyl phthalate. Most of them were not statistically significant. Subgroup analysis indicated that the heterogeneity was mainly found in the studies conducted in China and matrix collected at first trimester of pregnancy. Substantial heterogeneity and inconsistency of research methods may lead to inconsistent results of maternal phthalates exposure with preterm birth. We recommend a multicenter cohort study with a consistent approach to unravel the complex associations of prenatal phthalates exposure with birth outcomes.

Exposure to multiple metals and the risk of hypertension in adults: A prospective cohort study in a local area on the Yangtze River, China.

BACKGROUND: Exposure to multiple metals is recognized as a common and real scenario in daily life. However, limited prospective studies have assessed associations between multiple metals exposure and hypertension. METHODS: In total, 2625 adults in a local area on the Yangtze River were investigated at baseline from 2014 to 2015 and followed up in 2019. We measured baseline urine levels of 22 metals and used multivariate logistic analysis and Bayesian kernel machine regression (BKMR) to explore associations between multiple metals exposure and the risk of hypertension. RESULTS: A total of 385 individuals (29.6%) were diagnosed with hypertension. Five metals (cadmium, copper, magnesium, molybdenum and zinc) were positively associated with hypertension in single-metal models. Cadmium and zinc remained significantly positive associations after adjusting for these five metals, with the odds ratio (OR) in the highest quartiles of 1.49 (95% CI: 1.01, 2.21; p-trend = 0.05) and 1.60 (95% CI: 1.08, 2.38; p-trend = 0.02), respectively. BKMR analysis showed a significant joint effect of multiple metals on hypertension when the concentrations of five metals were at or above their 55th percentile compared with their median values. A potential interaction between cadmium and zinc in increasing the risk of hypertension was observed with the ORint of 1.41 (95%CI: 1.05, 1.89). CONCLUSIONS: We identified the joint effect of multiple metals on hypertension and observed a significant interaction between cadmium and zinc. Further cohort studies are needed to clarify the health effects of multiple metals exposure in a larger population.

[Relationship between the postmortem interval and nuclear DNA changes of heart muscular cells in mice].

OBJECTIVE: To study the changes of DNA degradation in cells of rats and its relationship with the postmortem interval. METHOD: 8 parameters of cell nuclear (including the tail length, the head radius, the percentage of head DNA, the percentage of tail DNA, the tail moment, the olive moment, the head area and the tail area) were chosen to study their changes in the procedure of DNA degradation in myocardium cells in 111 rats at different postmortem interval from 0 to 72 h by using single-cell gel electrophoresis (SCGE) technology and fluorescent microscope combined with auto-analysis-image system method. RESULTS: An evident comet tailing was observed in DNA of myocardium cells after electrophoresis, and their changes in all these 8 parameters of cell nuclear were greatly associated with the extension of postmortem interval, which indicate the degradation rate and degree of DNA in the nuclear has a close relationship with postmortem interval in the periods from 0 to 72 h in rats and significant difference were found with those groups (P < 0.001). CONCLUSION: The equations, which were concluded from our study, indicate the close relationship of degradation rate and degree of DNA in the nuclear with postmortem interval from 0 to 72 h, and provide an objective and exact new way to estimate the postmortem interval.