Prevalence and correlates of subclinical hypothyroidism in young first-episode drug-naïve major depression patients with high BMI

Both subclinical hypothyroidism (SCH) and overweight or obesity are prevalent in major depressive disorder (MDD), with inconsistent results due to differences in inclusion criteria in previous studies. Few previous studies have compared the prevalence and influencing factors of SCH in MDD patients accompanied by overweight or obesity between those who are not. The aim of our study was to examine the prevalence of SCH and associated risk factors among young Chinese first-episode drug-naïve (FEND) MDD patients with overweight or obesity and exclude the impact of age and medication. This study recruited a total of 1289 young FEDN MDD outpatients and their demographic data, clinical information, thyroid function and biochemical parameters were collected. They were also assessed on the Hamilton Depression Inventory (HAMD), Hamilton Anxiety Inventory (HAMA), and Positive and Negative Symptom Scales (PANSS). The incidence of SCH in young FEDN MDD patients with overweight or obesity was 65.78%, which was 1.59 times higher than that in patients without high BMI (28.6%). Patients with SCH had longer duration of illness, higher HAMA, HAMD, and PANSS positive symptom scores, stronger suicide attempts, higher blood pressure (BP), higher fasting blood glucose, total cholesterol (TC) levels and low-density lipoprotein (LDL) levels, and lower high-density lipoprotein (HDL) levels than those without SCH. Additionally, logistic regression showed that the HAMD score, fasting blood glucose, TC levels, HDL-C levels, systolic and diastolic BP were significantly associated with SCH. Furthermore, the combination of TC levels and systolicBP could differentiate patients with SCH from those without SCH. Our results suggested a high incidence of SCH in young MDD patients with high BMI. The severity of depression and several metabolic parameters contribute to the incidence of SCH in young MDD patients with high BMI.