The Relationship between Serum Thyrotrophic and Components of Metabolic Syndrome

Abstract

Khalid S Aljabri and Samia A Bokhari

Background and objective: Metabolic syndrome (Meets) is a cluster of obesity, hyperglycemia, dyslipidemia and hypertension (HTN). Thyroid hormones play an important role in regulating energy homeostasis, carbohydrate, lipids and protein metabolism. Therefore the present study was an effort to investigate the influence of TSH levels in each component of patients with Meets in a population of Saudi Arabia.

Design: We analyzed retrospectively 656 participants with MetS whom are between the ages 20 to 98 years. All patients were from the population of the Primary health centre at King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia. All data were collected on the basis of a review of electronic medical data. Patient who are pregnant were excluded. The reference range values of TSH 0.22-4.2 MIU/L, Free T4 12.0-22.0 pmol/L. TSH was divided into three groups; <1.5, 1.5-2.5 and >2.5-4.2. Metabolic risk factors were defined using the 2006 IDF criteria that define elevated triglyceride as ≥150 mg/dL (≥1.7 mmol/L) and reduced high density lipoprotein cholesterol (HDL) as <40 mg/dL (<1.03 mmol/L) for male and as <50 mg/dL (<1.29 mmol/L) for female. Elevated blood pressure was defined when the systolic blood pressure was ≥130 mm Hg and/or diastolic blood pressure was ≥85 mm Hg in addition to receiving any medication for HTN. Abnormal glucose metabolism was con¬sidered when HbA1c (≥5.7) or when patients were known to have type 2 diabetes mellitus (T2DM). The total number of cohort was separated on basis of age values into four groups: <40 years, 40-49 years, 50-59 years and ≥60 years.

Results: 656 subjects with MetS were included. There were 86 (13.1% ) male and 570 (86.9%) were female with mean age 55.6 ±12.7 with mean body mass index 32.8 ± 7.2 kg/m2 . HbA1c>5.6 or T2DM, hypertension, triglyceride (≥1.7 mmol/l) and low HDL were present in 94 (14.3%), 354 (54.0%), 328 (50.2%) and 487 (74.2%) respectively. The mean TSH and FT4 values were 2.1 ±1.0 mIU/l and 15.4 ±3.1 pmol/l respectively. Patients with TSH (>2.5-4.2) were non-significantly younger and have significantly higher BMI compared to patients with TSH (<1.5) or TSH (1.5-2.5), 50.9 ±12.4 vs. 53.5 ±12.7 vs. 53.4 ±13.0 respectively, p=0.05 and 33.6 ± 8.2 vs. 31.7 ± 6.1 vs. 33.2 ± 7.0 respectively, p=0.01. Females compared to males were non-significantly predominant in patients with TSH (>2.5-4.2) compared to patients with TSH (<1.5) or TSH (1.5-2.5), 87.3 vs. 12.7%, 89.4 vs. 10.6% and 84.0 vs. 16.0%, p=0.2. Cases with HbA1c>5.6 or T2DM were significantly more prevalent in patients with TSH (>2.5-4.2) compared to TSH (<1.5) or TSH (1.5-2.5), 18.8% vs. 13.9% vs. 10.0 respectively, p=0.03. Cases with HTN were significantly less prevalent in patients with TSH (>2.5-4.2) compared to TSH (<1.5) or TSH (1.5-2.5), 46.3% vs. 54.3% vs. 61.6 respectively, p=0.005. Cases with serum triglyceride (≥1.7 mmol/l) were significantly more prevalent in patients with TSH (>2.5-4.2) compared to TSH (<1.5) or TSH (1.5-2.5), 57.6% vs. 44.9% vs. 47.2 respectively, p=0.02. Cases with low HDL were significantly more prevalent in patients with TSH (>2.5-4.2) compared to TSH (<1.5) or TSH (1.5-2.5), 85.1% vs. 74.9% vs. 71.1 respectively, p=0.002. Higher prevalence of HbA1c>5.6 or T2DM, low HDL , triglyceride (≥1.7 mmol/l) and HTN in patients with age 40-59 years compared to <40 years or more than 60 years, p<0.0001, p=0.4, p=0.02 and p=0.3 respectively.

Conclusion: We found that an increase in serum TSH was positively correlated with components of metabolic syndrome and might be a risk factor for metabolic syndrome in Saudis. Further investigations are essential to further confirm the relationship between TSH and components of metabolic syndrome in Saudis as well as the underlying mechanism(s)

PDF