Associations of thyroid-stimulating hormone and free thyroxine concentrations with health and life satisfaction in elderly adults.

OBJECTIVE: To analyze associations between thyroid-stimulating hormone (TSH) and free thyroxine (FT4 concentrations and life satisfaction, symptoms, self-rated health, and common neuropsychiatric diseases (depression or dementia) in a community-dwelling elderly population to provide evidence whether to decrease the upper reference limit for TSH or the optimal TSH target in levothyroxine treatment in older adults.

METHODS: In this cross-sectional study, we determined TSH and FT4 concentrations in a thyroid disease-free population of 502 men (median age, 71 years) and 584 women (median age, 73 years) and in a patient group of 49 women (median age, 75 years) with primary hypothyroidism who were stable users of thyroxine treatment. Life satisfaction, self-rated health, depression, and dementia were assessed with specific questions and with tools such as the Self-report Depression Scale and the Mini-Mental State Examination. Independent variables were dichotomized, and associations of these variables with TSH and FT4 levels were assessed in the thyroid disease-free population. Levels of TSH and FT4 in thyroid disease-free women and in women treated with thyroxine were also compared.

RESULTS: After age adjustment, there were no associations between TSH levels and self-rated health, life satisfaction, or most symptoms in the thyroid disease-free population. No associations were found between diagnosed depression or Mini-Mental State Examination results and levels of TSH and FT4. Dementia was associated with higher FT4 concentration in men. Although women treated with thyroxine had TSH levels that were higher than thyroid disease-free women, there were no statistically significant differences in independent variables between these 2 groups.

CONCLUSION: Our results do not support the need to decrease the upper reference limit for TSH or to lower the optimal TSH target in levothyroxine treatment in older adults, as recommended in recent guidelines.