Abstract
BACKGROUND: Despite the abundance of literature, the relationship between hypothyroidism and depression is not clearly defined. We conducted this study to investigate the association of thyroid functioning [measured by serum Thyroid Stimulating Hormone (TSH) level] with depression [measured by Patient Health Questionnaire-9 (PHQ-9)] in a population-based study. Method: This is a cross-sectional and longitudinal study, which included all adult patient who received care at the Marshfield Clinical Health System from 2015 through 2020 and had one or more TSH and PHQ-9 measurement pair within 6 months. Logistic regression was used to estimate the effect of TSH level on depression in patients without or with thyroid diseases (untreated thyroid disease- not on any thyroid medications and treated thyroid disease - on thyroid medications). Candidate models included depression regressed on (1) TSH, (2) log-transformed TSH, (3) TSH level: normal (0.5-4.9), elevated (5. 0-9.9), very elevated (≥10), and model fit statistics were used to select the TSH-level model. Patient characteristics that were significantly associated with TSH level were included as covariates including Charlson Score. RESULTS: 127,587 unique patients with 236,799 pairs of PHQ-9 and TSH were identified from Electronic Medical Record (EMR) data base. The average age was 53.6 (19.1) years, 90.4% were Caucasians, and 66.2% were females. 87.8% had no depression, 4.4% had minimal depression, and 3.6% had moderate depression, while rest had severe depression. 5.4% had low TSH, 85.8% had normal TSH, 6.8% had elevated and 2. 0% had very elevated TSH. 38.6% had thyroid disease, off which 32.6% were treated In adjusted model, patients without thyroid disorder did not have an increased risk of depression with elevated and very elevated TSH. However, patients with untreated thyroid disorder had increased risk of depression with very elevated TSH (OR=2. 08, 95% CI: 1.39-3.12), while patients with treated thyroid disorder had increased risk of depression with elevated (OR=1.15, 95% CI: 1. 03-1.27) and very elevated TSH (OR=1.26, 95% CI: 1.11-1.42) Conclusions: This large cohort study suggests that there is no association between TSH and depression in patients without any thyroid disorders. However patients with thyroid disorders do have higher risk of depression with elevated TSH level. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.