An examination of the relationship between normal range thyrotropin and cardiovascular risk parameters: A study in healthy women
ABSTRACT To investigate the relationship between thyrotropin concentrations within the accepted reference range and cardiovascular risk.
Initially, 728 women aged 45-60 years were enrolled over a 12-month period. All participants underwent full cardiovascular assessment, including detailed health questionnaire, sphygomanometry, body mass index (BMI) calculation, fasting glucose and lipid profiling, and measurement of serum thyrotropin concentrations. Patients whose thyrotropin concentrations were within the reference range (0.5-4.5 mU/L) were divided into quartiles (n = 629). The means of cardiovascular risk parameters between the first (n = 158) and fourth (n = 157) quartile were compared. Subsequently, the relationships between thyrotropin concentration and risk parameters for cardiovascular disease were examined.
This study demonstrates that, within the reference range, increasing thyrotropin concentrations are associated with increasing risk parameters for the development of cardiovascular disease. Subjects with thyrotropin concentrations within the uppermost quartile of the reference range had significantly increased waist circumference, BMI, glucose, triglyceride, and systolic blood pressure measurements when compared to those in the lowermost quartile. Furthermore, significant relationships between thyrotropin and waist circumference, BMI, and fasting glucose and triglycerides concentrations were demonstrated. Finally, independent relationships between thyrotropin and both fasting glucose and triglyceride concentrations were demonstrated.
Within the reference range, increasing thyrotropin concentrations are associated with increasing cardiovascular risk parameters. Fasting glucose and triglycerides have been shown to be independently associated with thyrotropin concentration.
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ABSTRACT: To investigate the prevalence of subclinical thyroid dysfunction and the relationship between thyrotropin levels and cardiovascular risk factors in residents of the coastal area of China. Atotalof4256individuals(mean[±SD]age50.51±14.24years; 2079 males, 2177 females,) were enrolled in the present study. Sex, blood pressure, body mass index, waist-to-hip ratio, serum levels of fasting glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, uric acid and smoking status were measured. The relationship between thyrotropin levels and cardiovascular risk factors was analyzed. The overall prevalence of thyroid dysfunction was 11.07%. The prevalence of subclinical hypothyroidism (6.32%) was higher than that of hyperthyroidism (1.53%). The prevalence of thyroid dysfunction among female subjects was higher than that among male subjects (16.54% versus 5.34%, respectively; P<0.001). Significant differences were detected with respect to body mass index (P=0.026), waist-to-hip ratio (P<0.001), fasting glucose levels (P=0.001), total cholesterol levels (P=0.013), triglyceride levels (P=0.003) and smoking status according to different thyrotropin levels. The prevalence of thyroid dysfunction was high in residents of China's coastal area. Significant differences were detected with regard to body mass index, waist-to-hip ratio, fasting glucose levels, total cholesterol levels, triglyceride levels and smoking status according to different thyrotropin levels.Experimental and clinical cardiology 01/2013; 18(1):e16-e20. · 0.76 Impact Factor
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ABSTRACT: It is not clear whether or not subclinical hypothyroidism (SH) is associated with an increased risk for cardiovascular disease. We prospectively examined 43 women with SH and 49 healthy controls of similar age. Fasting blood levels of thyrotropin, free thyroxin, antibodies to thyroid peroxidase and thyroglobulin, glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and insulin were measured. Body mass index, waist and hip circumferences, blood pressure, homeostasis model assessment 2-insulin resistance index, and the presence of metabolic syndrome (MS) were also evaluated. Mean systolic blood pressure was increased in SH patients versus controls (128.6 vs. 120.7 mm Hg; P = 0.04). Mean values of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and insulin were not different in patients with SH compared with controls. SH had significantly higher triglyceride levels (1.50 ± 0.65 mmol/L) and glucose levels (5.26 ± 0.63 mmol/L) compared with controls (1.27 ± 0.59, 5.05 ± 0.52; P = 0.04, P = 0.04, respectively). Although body mass index values were similar in both groups, patients had greater waist circumference than controls (90.7 ± 13 cm vs. 81.8 ± 10.6; P = 0.0007). The percentages of patients with SH having hypertension (34.1%), hypertriglyceridemia (37.2%), hyperglycemia (20.9%), and greater waist circumference (51.2%) were higher than the percentages in controls. Thus, the percentage of MS in patients (41.5%) was significantly higher than in controls (12.2%; P = 0.003). SH had significantly higher likelihood of cardiovascular risks (odds ratio, 6.26; 95% confidence interval, 1.6–4.49; P = 0.008 for MS). We conclude that SH is associated with greater probability of MS. This may increase the risk of accelerated atherosclerosis and premature cardiovascular disease in these patients.The Endocrinologist 12/2009; 20(1):29-32. DOI:10.1097/TEN.0b013e3181cb47da · 0.12 Impact Factor
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ABSTRACT: Context:Subclinical hypothyroidism (SCH) and metabolic syndrome (MetS) increase with age, however their relation remains unclear.Objective:Our objective was to investigate the relation between SCH and indices of metabolic syndrome, and follow-up subjects for one year.Design:Cross-sectional and longitudinal follow-up studies of cases were collected from Takasaki Hidaka Hospital between 2003 and 2007.Participants:Overall, 11,498 participants of health check ups were analyzed. The mean age was 48 ± 9 years.Main Outcome Measures:Relation between SCH and indices of MetS were examined.Results:Serum free T4 (FT4) levels were lower in women than men in most of the age groups, and the prevalence of SCH, 6.3 % in women versus 3.4 % in man, increased with age, reaching 14.6 % in 70∼ year-old women. Multivariate logistic-regression analyses revealed that waist circumference, and the serum triglyceride and LDL-cholesterol levels were significantly higher in subjects with SCH than without among women. Reflecting these findings, the adjusted odds ratio (OR) of MetS in patients with SCH was higher than in the euthyroid subjects in women with OR, 2.7 (95% CI, 1.1-5.6; p=0.017), but not in men. Furthermore, progression from euthyroid into SCH resulted in a significant increase in the serum triglyceride level but not LDL-C in women.Conclusion:Japanese women exhibited a high prevalence of SCH associated with low FT4 levels. There was a strong association between SCH and several indices of metabolic syndrome in women. SCH may affect serum triglyceride levels and be a risk factor for metabolic syndrome.Precis:Subclinical hypothyroidism may affect the serum triglyceride level and be a risk factor for metabolic syndrome in Japanese women.The Journal of Clinical Endocrinology and Metabolism 06/2013; 98(8). DOI:10.1210/jc.2013-1353 · 6.31 Impact Factor
Cathal D Walsh