Objective: Based on the Mendelian randomization analysis, to assess the causal relationship between DNA methylation levels of Janus kinase 2 (JAK2) and obesity. Methods: A case-control study was carried out, including 1 021 individuals [obesity (visceral fat index ≥10) vs. no obesity (visceral fat index <10) was 440 vs. 581] from the Henan Rural Cohort Study. MethylTarget^TM target region methylation sequencing technology was used for testing the DNA methylation level of JAK2. logistic regression models were used to assess the association between the DNA methylation level of JAK2 and obesity. With SNP as the instrumental variable, the association between the DNA methylation level of JAK2 and obesity was explored by using the Mendelian randomization analysis method. Results: There was a positive association between Chr9:4984943 (one DNA methylation site in the promoter of JAK2) and obesity, and the OR (95%CI) was 1.22(1.04-1.42). Methylation level of five sites in the exon of JAK2 (Chr9:4985378, Chr9:4985404, Chr9:4985407, Chr9:4985409 and Chr9:4985435) were negatively associated with obesity, the corresponding OR (95%CI) were 0.53 (0.29-0.95), 0.58(0.36-0.93), 0.69 (0.49-0.97), 0.72 (0.53-0.99) and 0.58 (0.35-0.98) , respectively. Mendelian randomization analysis showed that there was a causal relationship between the DNA methylation levels of JAK2 and obesity, and the corresponding β (95%CI) were -1.985 (-3.520 - -0.450),-3.547 (-6.301 - -0.792) and -3.900 (-6.328 - -1.472) for Mendelian randomization method of inverse variance weighted, Mendelian randomization method of median based and Maximum-likelihood method, respectively. Conclusion: This study supported there was a causal relationship between the DNA methylation level of JAK2 and obesity.
Case-Control Studies ; Cohort Studies ; DNA Methylation ; Genome-Wide Association Study ; Humans ; Janus Kinase 2/genetics* ; Mendelian Randomization Analysis/methods* ; Obesity/genetics* ; Polymorphism, Single Nucleotide

Objective: The coronavirus disease 2019 (COVID-19) pandemic continues to present a major challenge to public health. Vaccine development requires an understanding of the kinetics of neutralizing antibody (NAb) responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: In total, 605 serum samples from 125 COVID-19 patients (from January 1 to March 14, 2020) varying in age, sex, severity of symptoms, and presence of underlying diseases were collected, and antibody titers were measured using a micro-neutralization assay with wild-type SARS-CoV-2. Results: NAbs were detectable approximately 10 days post-onset (dpo) of symptoms and peaked at approximately 20 dpo. The NAb levels were slightly higher in young males and severe cases, while no significant difference was observed for the other classifications. In follow-up cases, the NAb titer had increased or stabilized in 18 cases, whereas it had decreased in 26 cases, and in one case NAbs were undetectable at the end of our observation. Although a decreasing trend in NAb titer was observed in many cases, the NAb level was generally still protective. Conclusion We demonstrated that NAb levels vary among all categories of COVID-19 patients. Long-term studies are needed to determine the longevity and protective efficiency of NAbs induced by SARS-CoV-2.
Adult ; Aged ; Aged, 80 and over ; Antibodies, Neutralizing/immunology* ; Antibodies, Viral/immunology* ; COVID-19/immunology* ; Female ; Humans ; Kinetics ; Male ; Middle Aged ; Neutralization Tests ; SARS-CoV-2

Adult ; Aged ; China/epidemiology* ; Cohort Studies ; Female ; Humans ; Male ; Metabolic Syndrome/etiology* ; Middle Aged ; Parks, Recreational/supply & distribution* ; Prevalence ; Residence Characteristics/statistics & numerical data* ; Rural Population/statistics & numerical data* ; Young Adult