Thyroid function after menopause: is there any concern in thyroidology?

Menopause, per se, brings forth explicit physiological and biological alterations that affect assorted bodily systems, embodying the delicate endocrine gland, the thyroid. Throughout their lives, women experience symptoms related to hormonal fluctuations, such as headaches, muscle cramps, sleep disturbances, and mood swings. Thyroid dysfunction is another health concern that commonly arises during menopause. A clear link has been established between aging and thyroid dysfunction, with postmenopausal women being at increased risk due to age-related shifts in thyroid function ¹ . Herein, this paper addresses the concerns surrounding thyroid function in postmenopausal women, including diagnostic challenges, the impact of aging on thyroid health, and associated risks such as osteoporosis and malignity in thyroidology.

As women age, their endocrine system, including the thyroid gland, undergoes significant changes even without apparent disease. This process leads to a decline in T4 (thyroxine) production and an attenuated thyroid response to thyroid-stimulating hormone (TSH), resulting in higher TSH levels ^2–4 . TSH has been reported to follow a U-shaped curve in iodine-sufficient populations, with elevated levels in both younger and older individuals, while FT3 (free triiodothyronine) levels diminish with age ^5,6 . This de-escalation in thyroid function may provide a survival advantage for older adults, while younger individuals with low gland activity are at higher risk for cardiovascular diseases ⁷ . Therefore, age-specific reference intervals for thyroid evaluation in older women are crucial. In iodine-sufficient areas, older women are more likely to develop hypothyroidism ⁸ , a condition that can mimic many menopausal symptoms, including fatigue, memory problems, and muscle cramps ^9,10 . Similarly, hyperthyroidism can manifest with symptoms such as anxiety, sweating, palpitations, and insomnia symptoms also common during menopause, making diagnosis difficult ¹¹ . Thyroid hormones play an essential role in brain function by regulating cellular metabolism, gene expression, and neurotransmitter production, much like estrogen ¹² . As estrogen levels decline during menopause, it becomes increasingly important to distinguish between menopausal symptoms and thyroid dysfunction since both can impact cognitive health ¹³ .

Diagnosing thyroid dysfunction in postmenopausal women is often complicated by the overlap of symptoms between menopause and thyroid disorders. Both conditions can cause similar symptoms, such as palpitations, insomnia, and weight gain, making differentiation difficult. Additionally, interpreting thyroid function test results can be challenging due to age, comorbidities, and ongoing treatments ⁷ . To address this, the American Society of Clinical Endocrinology recommends routine thyroid screening for older women, especially those undergoing menopause ¹⁴ . Postmenopausal women face an increased risk of osteoporosis and fractures, conditions that can be worsened by thyroid dysfunction. Hyperthyroidism, including its subclinical forms, is associated with lower bone mineral density (BMD) and an elevated risk of fractures, particularly in the spine ¹⁵ . Several factors, including declining metabolic clearance and medication interactions, affect thyroxine requirements in the elderly. Excessive doses of thyroxine may lead to severe issues such as atrial fibrillation, bone density loss, and other tachyarrhythmias. As such, careful thyroid function monitoring and personalized treatment are essential to maintaining bone health in postmenopausal women ¹⁶ . In cases where TSH suppression is required after thyroidectomy for thyroid carcinoma, stringent suppression might negatively impact BMD and raise the risk of fractures, highlighting the importance of balancing the benefits of TSH suppression with its potential impact on bone health ^15,16 . Moreover, thyroid dysfunction is also linked to sexual dysfunction in women, a problem often exacerbated during menopause. While some studies suggest that correcting thyroid dysfunction can improve sexual function, the relationship between thyroid hormone levels and sexual health remains unclear. Of note, autoimmune thyroid diseases, in particular, have been associated with sexual dysfunction in women. Recently, an association between thyroid dysfunction and breast cancer risk, influenced by menopausal status, has been announced. As such, hyperthyroidism appears to increase the risk of breast cancer in postmenopausals, while hypothyroidism shows a stronger inverse relationship in premenopausal women. Thyroid hormones may contribute to breast cancer development through estrogen-like pathways. Additionally, an elevated thyroid hormone-to-estradiol ratio could promote breast cancer in postmenopausal women ^17,18 . Of note, these findings might help to identify at-risk women and improve understanding of the hormonal mechanisms involved in breast cancer ¹⁹ .

Given the symptom overlap between thyroid dysfunction and menopause, healthcare providers should remain vigilant in detecting thyroid disorders in postmenopausal women. In thyroidology, routine screening for thyroid disease ^20–25 is recommended, particularly for women with a history of surgical menopause or other risk factors. To this end, thyroidologists should also be mindful of potential issues with thyroid function tests, such as the interference caused by biotin supplements ^26,27 . A personalized approach to treatment is crucial when addressing both menopausal symptoms and thyroid dysfunction. Menopausal hormone therapy (MHT) can be a safe and effective option for managing both conditions, with evidence showing that MHT can prevent hip fractures without increasing thyroid cancer risk. However, it is essential, in order to avoid both under-treatment and over-treatment of thyroid disorders to reduce risks to cardiovascular and bone health ¹¹ .

Thyroid dysfunction poses significant challenges for postmenopausal women, as it can worsen or mimic menopausal symptoms, complicating diagnosis. Age-related changes in thyroid function, the augmented risk of thyroid carcinoma, and the impact of thyroid disorders on bone health highlight the need for routine screening and personalized care. Healthcare providers should take a patient-centered approach to be able to ensure the best outcomes for postmenopausals, considering their unique health requirements and preferences.