Introduction: Metabolic syndrome involves abdominal obesity, arterial hypertension, type 2 diabetes and lipid disorders manifested as atherogenic dyslipidaemia. Abnormal thyroid function affects the severity of MetS components, since regulating metabolism is one of the most important functions of thyroid hormones. In this study, we present the influence of hypothyroidism on lipid and carbohydrate disorders in patients with MetS.

Material and methods: The described study was a prospective, two-centre screening study of 24-month duration. The study participants were 441 patients (350 women, 91 men, aged 28–82) with metabolic syndrome diagnosed according to the 2005 IDF.

Results: By comparing the study and the control group, statistically significant differences were observed in the mean triglyceride levels (respectively 161,5 vs. 134,8 mg/dL, p = 0.047), mean fasting glycaemia (respectively 111,8 vs. 126,1 mg/dL, p = 0.044) and TG/HDL ratio (4,74 vs. 3,71, p = 0.043). Hypothyroidism shows a positive correlation with the TG levels and TG/HDL-C ratio and a negative correlation with the mean fasting glycaemia in people with MetS. A significantly higher TG/HDL-C ratio and lower mean insulin sensitivity ratio observed in men with hypothyroidism, indicated higher insulin resistance in men.

Conclusions: In view of the above, it may be hypothesized that in patients with both MetS and hypothyroidism, especially of male gender, the risk of death of cardiovascular causes is greater due to the severity of MetS components. Moreover, we suggest that in patients recently diagnosed with MetS, active detection of hypothyroidism should be performed by determining the TSH levels, while patients diagnosed with hypothyroidism (apart from replacement therapy) should be monitored for the possible occurrence of MetS in the future. (Endokrynol Pol 2015; 66 (4): 288–294)