Objective: To examine the dose-response association between cardiorespiratory fitness ( CRF ) and the risk of cardiovascular and cerebrovascular diseases. Methods: A joint search was performed in Chinese and English electronic databases, including China National Knowledge Infrastructure ( CNKI ) , Wanfang Data, VIP, CBM, PubMed, Embase and Web of Science, to retrieve publications reporting the correlation between CRF and the risk of cardiovascular and cerebrovascular diseases until May, 2021. The pooled risk was estimated using the random effects model, and the dose-response association was evaluated using restricted cubic splines. The source of heterogeneity was assessed by subgroup analysis, and the stability of the results was tested by the trim-and-fill method, while the publication bias was assessed using funnel plots. Results: Totally 37 280 literatures were identified, and 23 eligible studies were finally included in the analysis, which covered 2 605 622 subjects. There were 22 publications identified as high-quality. Meta-analysis revealed that the pooled risk of cardiovascular and cerebrovascular diseases reduced by 42% in the highest CRF group relative to the lowest CRF group ( OR=0.58, 95%CI: 0.52-0.65 ), and a one metabolic equivalent ( MET ) increase in CRF caused a 10% reduction in the pooled risk of cardiovascular and cerebrovascular diseases ( OR=0.90, 95%CI: 0.88-0.92 ). There was a negative linear correlation between CRF and the incidence of cardiovascular and cerebrovascular diseases ( P=0.396 ). Subgroup analysis identified gender, sample size and study regions as possible sources of heterogeneity, and sensitivity analysis showed that the study results were stable. Conclusions There is a negative linear correlation between CRF and the risk of cardiovascular and cerebrovascular diseases, and an increase in CRF may reduce the risk of cardiovascular and cerebrovascular diseases.

Objective To test the level of cell factor interleukin (IL)-21,CXCL13 in the plasma of patients with rheumatoid arthritis (RA),and to analyze the relationship between Follicular helper T cells(Tfh)and clinic features and discuss the possible immunological pathogenesis of RA.Methods The Tfh cells were obtained from patients and healthy controls (NC) and detected by Flow cytometery.While the levels of IL-21,CXCL13 in patients and NC were measured by ELISA tests.Those analysis were performed by student's t-test,one-way ANOVA,SNK-q test,Chi-square test,Spearman's correlation and multiple linear regression.Results The expression of CD4+CXCR5+ICOS+ cells (Tfh) in PBMCs of RA was significantly higher than normal controls (3.0±1.2 vs 1.1±0.4,P＜0.01).Meanwhile,the three RA groups of patients were divided to low,moderate and high disease activity groups,and the results showed that the expression of Tfh were increased accordingly (1.8±0.7,2.5±0.6,4.0±1.2).The expression of Tfh in the three groups were all significantly higher than that of controls (P＜0.01).There was a positive correlation between Tfh and DAS28,ESR,CRP,TJC,and bone erosion,RF and anti-CCP respectively.The expression of Tfh in those patients who had bone destruction was higher than those with no or mild bone destructions (2.7±1.1vs 3.4±1.3).The expression of Tfh in patients with un-treated RA patients,when compared to those RA patients who were treated appropriately and those who were not treated appropriately,was decreased significantly.The expression of Tfh in appropriately treated RA patients was lower than that without appropriately treatment.The level of IL-21,CXCL13 was decreased in patients with RA in the order of high,moderate,low disease activity and NC.Conclusion The expression of Tfh and the levels of IL-21,CXCL13 are increased significantly,and are closely related to disease activity and bone ersions.The expression of Tfh is decreased after relevant treatment.These results indicate that the abnormality of Tfh may play an important role in the pathogenesis of RA.