Background: Age-related physiological aging is associated with mild deficiency of thyroid function or subclinical hypothyroidism (sHT), especially in the elderly. Furthermore, in areas with high risk of pollution (Naples and Caserta known as “Terra dei Fuochi”, Italy), thyroid disorders are increasing and basically correlated with neoplastic development, probably due to environmental contamination. This study sets out to understand the relationship between the levels of free triiodothyronine (FT3) and thyroxine (FT4) with longevity, chronic disease and cancer development.
Patients and Methods: This cross-sectional observational pilot study recruited 80 subjects >85 years old, living in Campania (Southern Italy). 40 of them are healthy subjects (have not physical and mental disabilities) while others 40 subjects have cancer and often co-morbidities like chronic metabolic diseases. In both groups thyroid function parameters were measured in the frame of a comprehensive geriatric assessment.
Results: TSH and FT3 levels were statistically different in the 2 groups: (A) TSH low, FT3 high; (B) TSH high level, FT3 low. These two groups showed a different FT3/FT4 ratio: there were significantly two folds higher in the control group A (5.0) than in group B (2.6) (p=0.031).
Conclusions: Age-related subtle thyroid function due to high levels of FT3 seems to be related to longevity in the subject aged > 85 years. Also, further study in a large number of subjects needs to validate that the FT3/FT4 ratio could be predictive of the predisposition to the development of cancer, chronic diseases and the degree of disability.