| Objective: The global incidence of Metabolic Syndrome(Met S)is continuously increasing,making it a potential worldwide public health concern.Research on dietary factors related to Met S has attracted considerable academic attention in recent decades.The dietary factors associated with Met S constitute a nonlinear,self-organizing and dynamic complex system.It is difficult to analyze the internal relationship and interaction between dietary factors by traditional methods.In recent years,the complex network theory has been integrated into biomedical research,and the network topology has become an effective method to describe the complex relationship between variables.However,there are few reports on the complex network model and its research based on large sample epidemiological survey data.Therefore,whether we can effectively identify the main dietary factors that affect the Met S through the complex network method,and further verify the relationship between the intake level of the dietary factors and the risk of Met S,so as to find the epidemiological evidence,has become a challenging topic.In this study,firstly,through bibliometric method,we analyzed the research hotspots,knowledge structure and theme evolution in the field of dietary factors of Met S.Then,the complex network tools were used to identify the dietary factors affecting Met S.Finally,through a cross-sectional study,we further analyzed the relationship between dietary intake and the risk of Met S.To provide a scientific basis for the formulation of effective dietary strategies and measures to prevent and control the occurrence and development of Met S.Methods: First of all,bibliometric method was used to study the research hotspot,knowledge structure and theme evolution in the field of the dietary factors associated with Met S.Specifically: We searched the literature related to the dietary factors of Met S based on the Web of Science database,and constructed the high-frequency keyword-source papers binary discourse matrix and high-frequency keyword co-occurrence matrix by BICOMB 2.0 software.The g CLUTO version 1.0 software was used for biclustering analysis,and the clustering results were presented by visualization matrix and mountain visualization to obtain the frontier hotspots in the research field of the dietary factors associated with Met S.Ucinet version 6.186 software calculated the network centrality index of high-frequency keyword nodes,visualized the knowledge structure of the dietary factors associated with Met S,and screened out the key dietary nodes.By using Sci MAT version 1.1.04 software,this paper analyzed the Theme evolution of the research on the dietary factors associated with Met S through overlapping map,strategic diagrams and thematic evolution map,and explored the motor theme and potential theme in this field.Secondly,based on the baseline data of "Northeast regional natural population cohort",the population was divided into Met S group and non-Met S group according to the revised National Cholesterol Education Program Adult Group Third Report Diagnostic Criteria(ATP III).The data of 80 kinds of micronutrient intakes of the two groups were read by installing and using Minet 3.48.0 package in R 4.0.3.Miller-Madow estimator of build.min function was used to calculate mutual information among nutrient nodes and generate mutual information matrix.Mrnet algorithm was used to infer the weight of each pair of nutrients,and norm function was used to standardize the weight of each pair of nutrients,and the standardized weighted adjacency matrix of the two groups was obtained.The standardized weighted adjacency matrix of the two groups were imported into gephi 0.9.2software was used to draw the visualized network diagram of nutrient relationship between Met S group and non-Met S group,and to compare the network structure indexes(number of connected edges,average degree,network diameter,network density,average clustering coefficient and average path length),the most connected sub network and node importance indexes(clustering coefficient,weighted degree centrality,betweenness centrality,closeness centrality,and eigenvector centrality)differences.Objective to identify the major dietary nutrient nodes affecting Met S.Finally,according to the main dietary nutrients identified by the network,cross-sectional analysis was used to study the relationship between the dietary nutrient intake level and the risk of Met S.Specifically:variance analysis(continuous variables)and chi square test(categorical variables)were used to analyze the differences of baseline characteristics between Met S group and nonMet S group.Univariate and multivariate logistic regression models were used to analyze the relationship between major dietary nutrient intake and Met S.Followed by stratification according to the age,gender,BMI,physical activity,annual family income and education level of the subjects,the correlation between the main dietary nutrient intake and Met S was analyzed by multivariate logistic regression analysis.Results: part I: The research scope of dietary factors associated with Met S was gradually expanded,the content was constantly enriched,and the research tended to be stable,with strong theme continuity.The results of biclustering analysis showed that vitamin D,calcium,fruits and vegetables,fish oil,fatty acids,dietary fiber,coffee and polyphenols were the research hotspots of dietary influencing factors of Met S.The results of social network analysis showed that fatty acids,dietary fiber and polyphenols were the most active dietary nodes in the knowledge structure of dietary influencing factors of Met S,which played an important role in maintaining the stability of the knowledge structure network,improving the information exchange of each node and controlling the network resources.The results of theme evolution analysis showed that: in the strategic diagram of2000-2009,fatty acids were highly central and have great influence on other clusters.In the evolution diagram,fatty acids further evolved into calcium and dietary fiber.Calcium and dietary fiber evolved into dairy products and whole grains in the later stage.The motor theme of 2010-2014 was tea,and the motor themes of 2015-2020 were vitamin C and fish oil.Iron,prebiotics and zinc appeared independently in 2015-2020,and they were identified as emerging themes of dietary influencing factors of Met S.Part II: The prevalence of Met S in ethnic groups in Northeast China was 32.32%.The edges,average degree,network density,average clustering coefficient of the network in the Met S group were smaller than those in the non-Met S group,but the average path length was larger than that of the non-Met S group.The largest connected sub network of the two groups was extracted,and it was found that the nutrient nodes and the links of the nutrient network in the non-Met S group were more than those of the Met S population,?-sitosterol,rapeseed oil sterol,stigmasterol,?-sitosterol and soluble dietary fiber only appeared in the Met S group.However,phloretin,myricetin,zeaxanthin,candiphenyl,apigenin,resveratrol,resveratrol glucoside,paeoniflorin,delphinin,monounsaturated fatty acids and saturated fatty acids only appeared in the non-Met S group network.Among the two networks,the most central degree of weighted degree centrality was potassium element,and magnesium element has the highest betweenness centrality,closeness centrality and eigenvector centrality.The results showed that the largest difference of clustering coefficient between the two networks was alanine,followed by choline glycerophosphate,sphingomyelin,thiamine(vitamin B1)and saturated fatty acid.The largest difference of weighted degree centrality between the two networks was alanine,followed by serine,threonine,daidzein and saturated fatty acids.The largest difference of betweenness centrality between the two networks was thiamine(vitamin B1),followed by saturated fatty acids,? – carotene,copper and lecithin.Part III: Univariate logistic regression analysis showed that saturated fatty acid intake was negatively correlated with the prevalence of Met S.Compared with the lowest intake group,the OR(95% CI)of the second,third and fourth quartile were0.882(0.781,0.995),0.751(0.664,0.849)and 0.772(0.683,0.872)(P for trend< 0.0001),respectively.The results of dose-response relationship showed that the risk of Met S decreased by 8.9%(4.8%,13%)for each SD increase in saturated fatty acid intake.Model2 adjusted for age,gender,race,smoking,drinking and physical activity.Saturated fatty acid intake was negatively correlated with the prevalence of Met S.Compared with the lowest intake group,the OR(95% CI)of the second,third and fourth quartile were 0.873(0.772,0.987),0.746(0.657,0.846)and 0.800(0.703,0.910)(P for trend= 0.0002),respectively.The results of dose-response relationship showed that the risk of Met S decreased by 7.1%(2.6%,11.5%)when the saturated fatty acid intake increased by one SD.In model 3,total energy,carbohydrate,protein,total polyunsaturated fatty acids,total monounsaturated fatty acids,dietary fiber and cholesterol were adjusted continuously.Compared with the lowest intake group,the OR(95% CI)of the second,third and fourth quartile were 0.870(0.763,0.993),0.735(0.629,0.860)and 0.792(0.630,0.996)(P for trend= 0.0099),respectively.The protective effect of saturated fatty acids on Met S was still statistically significant.The results of dose-response relationship showed that there was no significant change in the risk of Met S for each SD increase in saturated fatty acid intake.After age stratification and adjustment for multiple potential confounding factors,compared with the saturated fatty acid intake with Q1 level,the risk of Met S in the group with Q3 saturated fatty acid intake level was lower,the OR(95% CI)were 0.505(0.296,0.866),0.744(0.580,0.953),respectively.The dose response relationship showed that the risk of Met S decreased by 29.4%(9.3%-45.3%)for every SD increase in saturated fatty acid intake in 60 and older age groups.After gender stratification and adjustment for multiple potential confounding factors among female,compared with the lowest intake group,the OR(95% CI)of the second,third and fourth quartile were 0.858(0.730,1.009),0.725(0.587,0.896)and 0.715(0.514,0.994)(P for trend= 0.016),respectively.Interaction analysis showed that the effect of saturated fatty acid intake on Met S was significantly affected by gender(P = 0.005).Stratified by BMI,after adjusting for multiple potential confounding factors,the results showed that compared with the saturated fatty acid intake level of Q1,the obese people with saturated fatty acid intake level of Q3 had lower risk of Met S,the OR(95% CI)was 0.761(0.626,0.926).Stratified by physical activity,after adjusting for multiple potential confounding factors,the results showed that in mild,moderate and severe physical activity group,compared with Q1 level of saturated fatty acid intake group,Q3 level of mild,moderate and severe physical activity group had lower risk of Met S,the OR(95% CI)were 0.744(0.565,0.981),0.686(0.484,0.970)and0.660(0.475,0.916),respectively.Stratified by family annual income and adjusted for multiple potential confounding factors,the results showed that in low-income group,compared with the group with saturated fatty acid intake at Q1 level,the risk of Met S in low-income group with saturated fatty acid intake at Q3 level could be reduced by 36%,with P for trend= 0.023.Stratified by education level,after adjusting for multiple potential confounding factors,the results showed that compared with the saturated fatty acid intake of Q1 level,the risk of Met S was lower in the people with saturated fatty acid intake of Q3 level,the OR(95% CI)were 0.574(0.347,0.947),0.749(0.590,0.951)and 0.649(0.451,0.938),respectively.Interaction analysis showed that the effect of saturated fatty acid intake on Met S was not significantly affected by age,BMI,physical activity,annual family income and education level(P > 0.05).Conclusion: 1.Dietary influencing factors of Met S research focus were vitamin D,calcium,fruits and vegetables,fish oil,fatty acids,dietary fiber,coffee,polyphenols.Fatty acids,dietary fiber and polyphenols were important dietary nodes in the knowledge structure of the dietary factors associated with Met S.Fatty acids,tea,vitamin C and fish oil were the motor theme in the research field of dietary factors associated with Met S,which have strong evolutionary ability.Prebiotics were a new topic in the study of dietary factors associated with Met S,and have great potential in the future.2.The intake of saturated fatty acids was significantly different between Met S and non Met S.Saturated fatty acid may be an important nutrient affecting Met S.The network scientific method can be used as a complementary tool for the study of nutritional epidemiology,which can provide additional information and is worthy of further promotion.3.The increased intake of saturated fatty acids is associated with a lower risk of Met S in ethnic groups in Northeast China.In the female population,increased saturated fatty acid intake is negatively correlated with the risk of Met S.It is suggested that increasing the intake of saturated fatty acids may reduce the risk of Met S in ethnic adult women in Northeast China. |
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