Objective To study the relationship between the low level lead exposure of pregnant woman and the gestational age of fetus. Methods The peripheral blood and the umbilical blood samples were collected from 1 000 healthy puerperants and their newborns. The puerperants were divided into three groups according to the blood lead levels: very low-level group(0.483 ?mol/L). Results The rate of premature labor was 9.40% in the very low-level group, 14.07% in the low-level group and 23.81% in the high-level group respectively. The blood lead level of puerperants had a positive correlation with the umbilical blood lead of newborns. The umbilical blood lead of premature was higher than that of mature. As the blood lead level of the pregnants increased, the gestational age shortened and the probability of low age premature increased. Conclusion As for the toxicity of lead to the fetus, there is no a threshold. Low level lead exposure of the pregnant woman is one of the causes of premature labor.

Chronic obstructive pulmonary disease(COPD)is a common respiratory disease with a high disability and mortality rate, and it has become one of the major public health issues of concern worldwide.It includes small airway disease and emphysema caused by abnormal tissue repair, but its pathogenesis is still unclear.COPD is currently viewed as a disease of accelerated lung aging and is closely associated with aging mechanisms such as telomere/telomerase, epigenetic changes and mitochondrial dysfunction.This article reviews research progress on the mechanisms linking COPD and aging-related regulation.

Objective:To investigate the clinical characteristics of first-episode and recurrent acute hypertriglyceridemic pancreatitis (HTGP).Methods:The retrospective cohort study was con-ducted. The clinical data of 313 patients with HTGP admitted to 26 medical centers in China in the Chinese Acute Pancreatitis Clinical Research Group (CAPCTG)-PERFORM database from November 2020 to December 2021 were collected. There were 219 males and 94 females, aged 38(32,44)years. Of the 313 patients, 193 patients with first-episode HTGP were allocated into the first-episode group and 120 patients with recurrent HTGP were allocated into the recurrent group. Observation indica-tors: (1) propensity score matching and comparison of general data of patients between the two groups after matching; (2) comparison of severity and prognosis in the course of disease within 14 days between the two groups; (3) the association between recurrent HTGP and the risk of persistent organ failure (POF); (4) follow-up. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent sample t test. Measurement data with skewed distribution were represented as M( Q1, Q3), and comparison between groups was conducted using the Wilcoxon rank sum test. Count data were expressed as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test. Comparison of ordinal data was conducted using the Wilcoxon rank sum test. The Kaplan-Meier method was used to plot the cumulative recurrence rate curve and Log-Rank test was used for survival analysis. The Logistic regression model was used for multivariate analysis, and continuous variables were converted into categorical variables according to the mean value or common criteria. Propensity score matching was performed by 1∶1 nearest neighbor matching method, with caliper value of 0.02. Paired t test or Wilcoxon rank sum test and McNemar′s test were used for comparison between matched groups. Results:(1) Propensity score matching and comparison of general data of patients between the two groups after matching. Of the 313 patients,208 cases were successfully matched, including 104 cases in the first-episode group and 104 cases in the recurrent group. After propensity score matching, there was no significant difference in demographic characteristics, severity of illness scores and laboratory test between the two groups ( P>0.05). The elimination of gender, acute physiology and chornic health evaluation (APACHE) Ⅱ score, computed tomography severity index score, systemic inflammatory response syndrome score, sequential organ failure assessment score, apolipoprotein E, C-reactive protein, creatinine, lactic acid dehydrogenase, procal-citonin confounding bias ensured comparability between the two groups. (2) Comparison of severity and prognosis in the course of disease within 14 days between the two groups. There were signifi-cant differences in POF and local complications between the first-episode group and the recurrent group ( P<0.05). (3) The association between recurrent HTGP and the risk of POF. Results of uncor-rected univariate analysis showed that there was no association between recurrent HTGP and the risk of POF ( odds ratio=0.78, 95% confidence interval as 0.46-1.30, P>0.05). Results of multivariate analysis after adjusting for covariates such as gender, age, APACHE Ⅱ score, C-reactive protein, triglyceride and total cholesterol showed that compared with first-episode HTGP, recurrent HTGP was associated with a higher risk of POF ( odds ratio=2.22, 95% confidence interval as 1.05-4.71, P<0.05). Results of subgroup analysis showed that age<40 years was associated with an increased risk of POF ( odds ratio=3.31, 95% confidence interval as 1.09-10.08, P<0.05). (4) Follow-up. Twelve of the 313 patients died during hospitalization, including 9 cases in the first-episode group and 3 cases in the recurrent group. The rest of 301 surviving patients, including 184 cases in the first-episode group and 117 cases in the recurrent group, were followed up for 19.2(15.5, 21.9)months. Results of follow-up showed that for 184 survived patients of the first-episode group, 164 cases were followed up and 24 cases experienced recurrence, for 117 survived patients of the recurrent group,29 cases experienced recurrence, showing a significant difference between the two groups ( χ2=4.67, P<0.05). Conclusion:Compared with first-episode HTGP, patients with recurrent HTGP are more prone to POF and local complications, and are more prone to recurrence after discharge. The risk of POF in recurrent HTGP patients is 2.22 times that of those with first-episode, and the risk is higher in patients with age <40 years.