The Relationship Between Serum Ferritin And Metabolic Syndrome In Adults

ObjectiveThis is a cross-sectional and cohort study based on a large sample of health examination population.To comprehensive access the gender-specific relationship between serum ferritin levels and metabolic syndrome(MS).MethodsStudy population from The Tianjin Chronic Low-grade Systemic Inflammation and Health(TCLSIHealth)Cohort Study.Participants were recruited while undergoing routine annual physical examinations at the Health Management Centre of Tianjin Medical University General Hospital from 2007 to 2015.All participants voluntarily participated in the study and signed informed consent.After inclusion and exclusions criteria,23,952 participants were enrolled into the cross-sectional study.Furthermore,additional participants were excluded at baseline if they already had MS,or had a health examination only in 2015,or did not complete all health examinations during the follow-up,the final cohort study population included 7,545 participants with a mean duration of follow-up of 2.58 years(95% CI: 2.54–2.62).Investigators collected the data of physical examination,questionnaires and blood biochemical indicators.Variables were recorded using a standard protocol.MS was defined according to the new criteria of the Chinese medical doctor association branch of diabetes of 2013.Differences between groups with and without MS were examined using analysis of variance for continuous variables and logistic-regression analysis for categorical variables.Analysis of variance and logistic-regression analysis were used to analyze the characteristics differences according to the quintile groups of serum ferritin levels.In cross-sectional study,the presence of MS was used as dependent variables,and serum ferritin levels were used as independent variables in gender-specific quintiles.Multiple logistic regression analysis was used to examine the relationship between serum ferritin levels and MS.In cohort study,the occurrence of MS was used as dependent variables,and serum ferritin levels were used as independent variables in gender-specific quintiles.Cox proportional hazards regression models was used to evaluate serum ferritin levels in relation to risk of MS.A linear trend across increasing quartiles was tested,using the median value of each quartile as a continuous variable based on linear regression.ResultsIn cross-sectional study,the overall prevalence of MS was 34.0%,the prevalence of MS was significantly higher in males than in females(40.9% compared with 23.1%).After adjusting for potential confounders,such as age,sex,BMI,white blood cell count,smoking status,drinking status,and a family history of CVD,hypertension,hyperlipidaemia and T2 D,the overall prevalence of MS gradually increased with increasing of serum ferritin levels,the adjusted OR(95% confidence interval,CI)for metabolic syndrome across ferritin quintiles were 1.00(reference),1.18(1.06,1.31),1.37(1.24,1.52),1.72(1.56,1.91),and 2.28(2.06,2.52),respectively(P for trend <0.001).Similar results were also observed in males and females.In cohort study,there were significant differences between MS group and non-MS group in age,physical examination,biochemical results and living habits in baseline(P <0.05).According to ferritin quintiles,the results showed that there were clear linear association between BMI,WC,TC,TG,FBG and HDL-C and quintile groups of serum ferritin levels in males(P for trend < 0.05),similar association were also observed for females.The incidence of MS was 125 per 1000 person-years among males and 56 per 1000 person-years among females during follow-up.In general population,after adjusting for age,sex,BMI,white blood cell count,smoking status,drinking status,a family history of CVD,hypertension,hyperlipidaemia and T2 D,waist circumference,blood pressure,blood glucose,HDL-C,and triglyceride,the hazard ratios(95% CI)for MS across ferritin quintiles were 1.00(reference),0.91(0.78,1.06),1.00(0.86,1.16),0.99(0.85,1.15),and 1.07(0.93,1.24)(P for trend =0.13).Serum ferritin levels were not statistically related to the incidence of MS,similar results were also observed in males and females.ConclusionsIn cross-sectional study,the serum ferritin levels is positively associated with the prevalence of MS in adults,while after adjusting for potential confounders,especially for baseline triglyceride levels,there was no statistical relation between serum ferritin levels and the risk of incident MS in cohort study.The serum ferritin levels were not predictive of the onset of MS.Further studies are needed to explore the exact relationship between serum ferritin levels and MS.