[Matching in observational research: from the directed acyclic graph perspective].

Matching is a standard method for selecting research objects regarding the observational research, which controls confounding factors and improves statistical efficiency. However, its role in controlling confounding is not consistent in different observational studies. Matching can eliminate the confounding bias of matching variables in cohort studies, but checking on itself cannot eliminate confounding bias in case-control studies. In matched case-control studies, researchers may not accurately judge whether the variable is a confounder. Sometimes the variables that are not confounders are mistakenly matched. In that case, it will result in overmatching, which will lead to the decline of statistical efficiency or the introduction of unavoidable bias or increase of workload. If the real confounding factors are omitted, it will cause confounding bias. Therefore, researchers should consider what kind of matching variable selection criteria should be formulated. A directed acyclic graph is a visual graphic language that can show the complicated causality among different epidemiological research designs. This article analyzes the role of Matching in different observational research designs from the perspective of the directed acyclic graph, formulates the selection criteria for matching variables in matched case-control studies, and provides some reference suggestions for future epidemiological research design.

[Co-prevalence relationship analysis on different metabolic syndrome scores and behavioral risk factors in adults from Urumqi based].

Objective: To investigate the influence of the prevalence and co-prevalence of risk factors for metabolic syndrome on the scores of different levels of metabolic syndrome in people receiving physical examination in Urumqi. Methods: Using the 2017 Xinjiang Health Examination Database, a total of 175 927 people from 7 districts and 1 county in Urumqi were selected as subjects. Face-to-face survey and body measurements were used to collect cardiovascular risk factors and metabolic syndrome scores. Metabolic syndrome scores were used. For the 0-5 points at 6 levels, χ(2), χ(2) trend test, correlation analysis of ordered variable Kendall's tau-b, and logistic regression analysis of ordered results were used to analyze the influence of prevalence and co-prevalence of behavioral risk factors on the MS scores. Results: The percentages of 6 metabolic syndrome scores in the sample population were 23.82%, 27.87%, 22.41%, 16.03%, 8.02%, and 1.85%, respectively. The scores of metabolic syndrome were different in different age groups, ethnic groups, groups with different drinking rates, and groups with different dietary types, with the differences all significant (P<0.05).The MS score in men increased with the increase of oil/salt rate and excessive drinking rate (P<0.01). The score in women increased with the increase of the current smoking rate, oil/salt rate, and increased with the decrease of physical activity (P≤0.01). There was no significant difference in the distribution of regular drinking rates between different score groups (P>0.05). The scores of metabolic syndrome increased with the increase of risk factors (P<0.05). Ordered results logistic analysis found that in the men with ≥3 risk factors and the metabolic syndrome score was 1.15 (1.06-1.26) times higher than that in the men without risk factor, as well as in women with 2 risk factors and≥3 risk factors. The metabolic syndrome scores were 1.38 (1.22-1.55), 2.02 (1.53-2.66) times higher than those in the women without risk factors. Conclusions: The physical examination group in Urumqi, the more the metabolic syndrome disease behavior risk factors clustered, the higher the metabolic syndrome score was. Therefore, comprehensive intervention measures should be taken to control the different forms of metabolic syndrome to prevent the occurrence and progress of the disease.

Autophagic inhibitor attenuates rapamycin-induced inhibition of proliferation in cultured A549 lung cancer cells.

BACKGROUND: Increasing studies have suggested that rapamycin has inhibitory effect for cancer cell proliferation. AIM: The present study aimed to investigate the effect of rapamycin on the proliferation of A549 lung cancer cells and try to elucidate its probable mechanism. MATERIALS AND METHODS: A549 cells were randomly divided into the following 3 groups (n=6): the Dulbecco's modified Eagle's medium (DMEM) culture solution administered alone group (C group), the 10 nmol/l rapamycin administered alone group (R group) and the 5 mmol/l 3-methyladenine (3-MA) plus 10 nmol/l rapamycin administered group (MR group). Death percentage of A549 cells was observed and the levels of caspase-3, Beclin-1, and microtubule-associated protein 1 light chain 3-II (LC3-II) were determined. RESULTS: Compared with C group, percentage of cell death, caspase-3, Beclin-1 and LC3-II both showed a significant increase in R group (p < 0.05). On the contrary, as compared with R group, percentage of cell death, caspase-3, Beclin-1 and LC3-II both showed a significant decrease in MR group (p < 0.05). CONCLUSIONS: Rapamycin has an inhibitory effect for the proliferation of A549 cells, and its mechanism is likely related to the activation of autophagic pathway.