What condition is indicated by low levels of T4?

Low levels of T4 (thyroxine) specifically indicate thyroid dysfunction, primarily hypothyroidism, which falls under the broader category of thyroid disease. T4 is a critical hormone produced by the thyroid gland, and its levels in the bloodstream are essential for maintaining metabolic processes in the body.

When T4 levels are low, it suggests that the thyroid gland is not producing enough hormone, leading to a range of symptoms including fatigue, weight gain, and sensitivity to cold. Since T4 is central to the thyroid's function, low levels directly point to a problem with the thyroid itself, making "thyroid disease" the most appropriate choice.

The other options do not directly relate to low T4 levels. Hyperthyroidism is characterized by high levels of thyroid hormones, typically including T4. Menopause pertains to hormonal changes related to reproductive hormones in women and does not involve T4. Growth hormone deficiency relates to a lack of growth hormone and does not influence T4 levels either. Thus, the association of low T4 levels with thyroid disease is clear and definitive.