TOPLINE:
Women with hypothyroidism treated with levothyroxine show no significant cognitive decline across the menopausal transition compared with those without thyroid disease.
METHODOLOGY:
- Levothyroxine, the primary treatment for hypothyroidism, has been linked to perceived cognitive deficits, yet it is unclear whether this is due to the underlying condition being inadequately treated or other factors.
- Using data collected from the Study of Women’s Health Across the Nation, which encompasses five ethnic/racial groups from seven centers across the United States, researchers compared cognitive function over time between women with hypothyroidism treated with levothyroxine and those without thyroid disease.
- Participants underwent cognitive testing across three domains — processing speed, working memory, and episodic memory — which were assessed over a mean follow-up of 13 years.
- Further analyses assessed the impact of abnormal levels of thyroid-stimulating hormone on cognitive outcomes.
TAKEAWAY:
- Of 2033 women included, 227 (mean age, 49.8 years) had levothyroxine-treated hypothyroidism and 1806 (mean age, 50.0 years) did not have thyroid disease; the proportion of women with premenopausal or early perimenopausal status at baseline was higher in the hypothyroidism group (54.2% vs 49.8%; P = .010).
- At baseline, levothyroxine-treated women had higher scores for processing speed (mean score, 56.5 vs 54.4; P = .006) and working memory (mean score, 6.8 vs 6.4; P = .018) than those without thyroid disease; however, no difference in episodic memory was observed between the groups.
- Over the study period, there was no significant difference in cognitive decline between the groups.
- There was no significant effect of levothyroxine-treated hypothyroidism on working memory or episodic memory, although an annual decline in processing speed was observed (P < .001).
- Sensitivity analyses determined that abnormal levels of thyroid-stimulating hormone did not affect cognitive outcomes in women with hypothyroidism.
IN PRACTICE:
When cognitive decline is observed in these patients, the authors advised that “clinicians should resist anchoring on inadequate treatment of hypothyroidism as the cause of these symptoms and may investigate other disease processes (eg, iron deficiency, B12 deficiency, sleep apnea, celiac disease).”
SOURCE:
The study, led by Matthew D. Ettleson, Section of Endocrinology, Diabetes, and Metabolism, University of Chicago, was published online in Thyroid.
LIMITATIONS:
The cognitive assessments in the study were not designed to provide a thorough evaluation of all aspects of cognitive function. The study may not have been adequately powered to detect small effects of levothyroxine-treated hypothyroidism on cognitive outcomes. The higher levels of education attained by the study population may have acted as a protective factor against cognitive decline, potentially biasing the results.
DISCLOSURES:
The Study of Women’s Health Across the Nation was supported by grants from the National Institutes of Health (NIH), DHHS, through the National Institute on Aging, the National Institute of Nursing Research, and the NIH Office of Research on Women’s Health. The authors declared no conflicts of interest.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.