BACKGROUND:In recent years,epidemiological studies have shown that obesity is a risk factor for knee osteoarthritis,and fatty acid intake,metabolism and biosynthesis are closely related to the development of obesity.However,the causal relationship between fatty acids and osteoarthritis is still unknown.OBJECTIVE:Using the Mendelian randomization analysis to investigate the causal relationship between five fatty acid phenotypes and knee osteoarthritis.METHODS:The genome-wide association study data on fatty acid ratios from the UK Biobank(met-D)and genome-wide association study data on knee osteoarthritis from the EBI-A database were pooled together.Single nucleotide polymorphisms were used as instrumental variables and sensitive single nucleotide polymorphisms were selected for analysis.Two-sample Mendelian randomization analysis was conducted to evaluate the causal relationship between fatty acids and knee osteoarthritis outcome risk.We used inverse variance weighting method,MR-Egger regression method,weighted median method,weighted model method,and simple model method to study the causal relationship between fatty acids and knee osteoarthritis.Further inverse Mendelian randomization analysis was performed in the same way to ensure the validity of the results.RESULTS AND CONCLUSION:The forward analysis and inverse variance weighting method showed a causal relationship between three types of fatty acid phenotypes and knee osteoarthritis.Among them,the proportion of saturated fatty acids to total fatty acids was positively correlated with the risk of knee osteoarthritis(odds ratio[OR]=1.825,95%confidence interval(CI):1.230,2.706,P=0.003),the proportion of omega 3 polyunsaturated fatty acids to total fatty acids was negatively correlated with the risk of knee osteoarthritis(OR=0.822,95%CI:0.688 8,0.981,P=0.03),and the proportion of omega 6 polyunsaturated fatty acids to total fatty acids was positively correlated with the risk of knee osteoarthritis(OR=1.268,95%CI:1.079,1.491,P=0.004).There were two types of fatty acid phenotypes that do not have a causal relationship with knee osteoarthritis,including total fatty acids(OR=0.925,95%CI:0.804-1.066,P=0.283)and the proportion of monounsaturated fatty acids to total fatty acids(OR=0.877,95%CI:0.756-1.018,P=0.084).The reverse analysis results indicated that when knee osteoarthritis was used as exposure data,there was no significant causal relationship with the phenotype of fatty acids.The sensitivity analysis results showed that the P-values of the bidirectional Mendelian randomization Cochran's Q-test and MR Egger regression were both greater than 0.05,indicating that there was no significant heterogeneity or pleiotropy in the causal effect analysis between fatty acid phenotype and knee osteoarthritis.To conclude,reducing the content of saturated fatty acids and omega 6 polyunsaturated fatty acids and increasing the content of omega 3 polyunsaturated fatty acids can reduce the risk of knee osteoarthritis.This provides valuable clues for studying the biological mechanisms of knee osteoarthritis and exploring the early prevention and treatment of knee osteoarthritis,as well as providing new directions for the development of interventional drugs.

BACKGROUND:In recent years,epidemiological studies have shown that obesity is a risk factor for knee osteoarthritis,and fatty acid intake,metabolism and biosynthesis are closely related to the development of obesity.However,the causal relationship between fatty acids and osteoarthritis is still unknown.OBJECTIVE:Using the Mendelian randomization analysis to investigate the causal relationship between five fatty acid phenotypes and knee osteoarthritis.METHODS:The genome-wide association study data on fatty acid ratios from the UK Biobank(met-D)and genome-wide association study data on knee osteoarthritis from the EBI-A database were pooled together.Single nucleotide polymorphisms were used as instrumental variables and sensitive single nucleotide polymorphisms were selected for analysis.Two-sample Mendelian randomization analysis was conducted to evaluate the causal relationship between fatty acids and knee osteoarthritis outcome risk.We used inverse variance weighting method,MR-Egger regression method,weighted median method,weighted model method,and simple model method to study the causal relationship between fatty acids and knee osteoarthritis.Further inverse Mendelian randomization analysis was performed in the same way to ensure the validity of the results.RESULTS AND CONCLUSION:The forward analysis and inverse variance weighting method showed a causal relationship between three types of fatty acid phenotypes and knee osteoarthritis.Among them,the proportion of saturated fatty acids to total fatty acids was positively correlated with the risk of knee osteoarthritis(odds ratio[OR]=1.825,95%confidence interval(CI):1.230,2.706,P=0.003),the proportion of omega 3 polyunsaturated fatty acids to total fatty acids was negatively correlated with the risk of knee osteoarthritis(OR=0.822,95%CI:0.688 8,0.981,P=0.03),and the proportion of omega 6 polyunsaturated fatty acids to total fatty acids was positively correlated with the risk of knee osteoarthritis(OR=1.268,95%CI:1.079,1.491,P=0.004).There were two types of fatty acid phenotypes that do not have a causal relationship with knee osteoarthritis,including total fatty acids(OR=0.925,95%CI:0.804-1.066,P=0.283)and the proportion of monounsaturated fatty acids to total fatty acids(OR=0.877,95%CI:0.756-1.018,P=0.084).The reverse analysis results indicated that when knee osteoarthritis was used as exposure data,there was no significant causal relationship with the phenotype of fatty acids.The sensitivity analysis results showed that the P-values of the bidirectional Mendelian randomization Cochran's Q-test and MR Egger regression were both greater than 0.05,indicating that there was no significant heterogeneity or pleiotropy in the causal effect analysis between fatty acid phenotype and knee osteoarthritis.To conclude,reducing the content of saturated fatty acids and omega 6 polyunsaturated fatty acids and increasing the content of omega 3 polyunsaturated fatty acids can reduce the risk of knee osteoarthritis.This provides valuable clues for studying the biological mechanisms of knee osteoarthritis and exploring the early prevention and treatment of knee osteoarthritis,as well as providing new directions for the development of interventional drugs.

Objective To investigate the value of the combined test in the diagnosis of thalassemia and iron deficiency anemia (IDA) .Methods From August 2013 to February 2015 ,36 patients with thalassemia ,34 patients with IDA ,and 30 healthy people who had undergone physical examination were enrolled in the study .The blood samples of those people were tested ,and items of the combined test included content of red blood cell volume(MCA) ,red blood cell volume distribution width(RDW) ,hemoglobin(Hb) electrophoresis and red blood cell(RBC) .Results The patients with IDA or thalassemia had reduced MCA and RBC fragile ,pa‐tients with IDA had increased RDW ,and patients with thalassemia had increased HbA2 ,compared with the control group the differ‐ences were all statistically significant(P<0 .05) .The sensitivity of RDW to IDA was 70 .6% ,and to thalassemia was 77 .8% ,the difference was not statistically significant (P> 0 .05) .The sensitivities of MCV ,Hb electrophoresis ,RBC fragility to thalassemia were 97 .2% ,88 .9% ,77 .8% respectively ,and the specificity were 80 .0% ,90 .0% ,83 .3% respectively .The sensitivities of MCA test combined with Hb electrophoresis ,hemoglobin electrophoresis combined with RBC brittleness test and parallel combined test of MCA ,Hb electrophoresis and RBC brittleness to thalassemia were 100 .0% ,97 .2% ,100 .0% respectively ,which were significantly higher than those of single tests ;the specificities were 96 .7% ,100 .0% and 100 .0% respectively ,which were significantly higher than those of single tests ;the differences were statistically significant(P<0 .05) .Conclusion The application of hematological pa‐rameters ,Hb and RBC in the diagnosis of anemia and IDA could significantly improve the diagnostic accuracy ,and it is worthy of popularization and application .