Prevalence of hypothyroidism in patients with metabolic syndrome

Aim: Hypothyroidism and metabolic syndrome are well-associated risk factors for atherogenic cardiovascular disease. Insulin resistance, being a common pathogenic mechanism in both, can cause a considerable overlap between hypothyroid and metabolic syndrome population. This cross-sectional study was intended to assess the thyroid function in patients with metabolic syndrome and to investigate the association between hypothyroidism and metabolic syndrome. Materials and Methods: One hundred patients with metabolic syndrome as per National Cholesterol Education Program-Adult Treatment Panel (NCEP ATP) III criteria and 50 controls (0 out of 5 criteria) attending the internal medicine outpatient clinic were included in the study. Patients were subjected to anthropometry, evaluation of vital parameters, and lipid and thyroid profile, along with other routine laboratory parameters. Students' t test, Chi-square test, linear regression, and multiple logistic regression models were used for statistical analysis. P value <0.05 was considered significant. Results: Body mass index, waist circumference, mean systolic pressure, diastolic pressure, fasting blood sugar, total cholesterol, low density lipoprotein (LDL) cholesterol, triglycerides, and thyroid stimulating hormone (TSH) were significantly higher, and free triiodothyronine (FT3), free thyroxine (FT4), and high density lipoprotein (HDL) cholesterol were significantly lower in the study group compared to the control group. In the metabolic syndrome group, 22 had subclinical hypothyroidism (22%), 4 were overtly hypothyroid (4%), and 74 were euthyroid (74%). Subclinical hypothyroidism was significantly associated with metabolic syndrome group (P = 0.032). There was significant linear association between TSH levels and total cholesterol, triglycerides, LDL cholesterol, and HDL cholesterol across the metabolic syndrome group in the linear regression model. Multiple logistic regression analysis recognized the association between body mass index with subclinical hypothyroidism (P = 0.006) in the metabolic syndrome group. Conclusion: It is concluded from this study that there is significant association between subclinical hypothyroidism and metabolic syndrome, and it highlights the importance of thyroid function tests in patients with metabolic syndrome.