| BackgroundIn the past decades, with the rapid development of economy and the improvement of people’s living standard day by day, a dramatic increased incidence of obesity has been attached overwhelmingly threatening people’s health, which has become a major global health concern. As a chronic metabolic disease, metabolic syndrome is characterized by an aggregation of multiple impaired metabolic components including obesity, hyperinsulinemia, hyperglycemia, hyperlipidemia, hyperuricemia as well as hypertension, which forms an intricate complex of metabolic disorder. Thyroid function, which has been observed to be closely associated with obesity for decades, is now again attracting more attentions of investigators since its intricate mechanisms underlying especially the findings of the novel independent role of thyroid stimulating hormone in adipocytes and obesity associated cardiovasculopathy were further revealed. Alternation in serum thyroid hormones levels especially the thyroid stimulating hormone levels can be referred as a prognostic indicator of metabolic syndrome. And the further study of the exact roles of thyroid hormones in obesity, would undoubtly provide novel insights into the understanding of the pathogenesis as well as the intervention strategies of obesity and its associated metabolic syndrome.ObjectiveTo evaluate the correlativity between serum thyroid hormones levels and the components of metabolic syndrome in euthyroid patients with morbid obesity MethodsIn this randomized, double-blinded study, a subcohort of158people with obesity (BMI≥25. Okg/m2with70male and88female),120people as health controls (18.5kg/m2BIM≤24kg/m2,with60male and60female) were randomly enrolled from a cohort of896people who took part in the routine medical checkup in community clinics of CNHTC JINAN TRUCK CO., LTD and Health examination center of Qilu Hospital of Shandong University. The average age of the participants is64+10years. Before performing the study, we explain the procedure in detail and obtain written informed consent from each participant. A detailed clinical questionnaire was also obtained from each patient including record of history of disease, physical and laboratory examinations by well trained professionals. Statistical procedures were performed with the statistical package PASW13.0. data were represented as Mean+SD (X±S). The Pearson or Spearman correlation test was used for correlation analysis depending on data distribution. Significance is defined as a two tailed P<0.05.ResultsThe demographic baseline parameters has no statistical significant difference among the three groups of participants,①compared with health controls, patients with obesity (defined as BMI≥25.0kg/m2) has significantly elevated systolic blood pressures and diastolic pressures (P<0.05); the levels of serum insulin, C-peptide as well as Hbl Ac are all higher in obese patients than those of health controls (p<0.001and p<0.05respectively). The serum levels of free T4(FT4) and thyroid stimulating hormone (TSH) was increased in euthyroid obese patients and statistically different (P<0.01).However, as for serum levels of free T3(FT3), there is a declining tedency in obseity, but in our present study, the difference is not statistically significa(P>0.05). Serum levels of High-density lipoprotein cholesterol ester (HDL-C) are significantly decreased in obese patients compared with health controls (P<0.01). But the increase in triglycerides are not statistically signifcant in our study (P>0.05).②compared with health people, patients with metabolic syndrome (MS) defined by diagnostic criteria made by Chinese Diabetes Society2004(CDS2004) have significantly elevated levels of blood pressures, body mass index (BMI)(P<0.01), serum insulin (P<0.01), serum C-peptide(P<0.01) and HblAc(P<0.01)。Furthermore, Both the serum lipid (including HDL-C(P<0.01), TG (P<0.01)and total cholesterol(P<0.01)) and the parameters of thyroid function (including TSH, FT4and FT3) reveal significant difference between patients with metabolic syndrome and health people (P<0.01)。③ompared with health people, patients with metabolic syndrome (MS) defined by diagnostic criteria from "Chinese guideline for prevention and treatment of adult dyslipidemia2007", again have significantly elevated levels of blood pressures, body mass index (BMI)(P<0.01), serum insulin (P<0.001), serum C-peptide (P<0.01) and HblAc (P<0.01)。Furthermore, Both the serum lipid (including HDL-C,TG and total cholesterol) and all the three parameters of thyroid function (including TSH (p<0.05), FT4(p<0.01) and FT3(P<0.05)) reveal significant difference between patients with metabolic syndrome and health people (P<0.01) as well。④The correlation study between serum TSH levels and each component of metabolic syndrome reveals significant positive relevance of serum levels of TSH with systolic blood pressures (p<0.05) and significant negative relevance of serum TSH levels with both insulin (p<0.05) and C-peptide (p<0.05) levels in obese patients. In lean health people, the significant positive correlation between serum TSH levels and WHR as well as cholesterol is revealed. Again serum TSH levels are negatively correlated with serum levels of both insulin (p<0.05) and C-peptide (p<0.05)ConclusionIn conclusion, Patients with metabolic syndrome, according to diagnostic criteria formulated by both CDS2004and Chinese guidelines on prevention and treatment of dyslipidemia in adults (2007), has a significant different serum levels of all the three parameters(FT3, FT4, TSH) of thyroid function(with respectively P<0.05、P<0.01、 P<0.001). Significantly elevated serum levels of FT4, together with TSH, was also observed in patients with obesity compared with lean health controls. Taken together, our study implicate that the function status of thyroid hormones may be closely linked to obesity as well as the obesity associated metabolic syndrome. Declined FT3, together with elevated FT4and TSH, may have a role in the pathogenesis of obesity as well as disease progression from obesity into metabolic syndrome. |
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