19 Sep People With Low Normal Thyroid Function Live Longer Than Those With High Normal
MedicalResearch.com Interview with:
Arjola Bano, MD, MSc, DSc
Researcher in the Departments of Internal Medicine and Epidemiology,
Erasmus Medical Center, Rotterdam
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Thyroid function is clinically defined by the measurements of serum thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels. So far, abnormal TSH and FT4 levels as well as variations within the normal range have been linked to an increased risk of cardiovascular disease and death. However, it remains unclear whether there are differences in life span and years of life lived with and without cardiovascular disease, within the reference range of thyroid function. To investigate this, we performed a prospective study among 7785 middle-aged and elderly people with normal thyroid function. Participants were part of the Rotterdam Study, 65 years on average and 52% females. In our statistical analyses, we accounted for sociodemographic and cardiovascular risk factors. Over a median follow-up of 8.1 years, 789 incident cardiovascular deaths and 1357 deaths occurred. Analyses were performed separately among men and women.
Our study found differences in life expectancy within the reference range of thyroid function. At the age of 50 years, people with low-normal thyroid function lived up to 3.5 years longer than those with high-normal thyroid function. Also, people with low-normal thyroid function lived a longer life without cardiovascular disease than those with high-normal thyroid function.
MedicalResearch.com: What should clinicians and patients take away from your report?
Response: At the age of 50 years, individuals with low-normal thyroid function lived longer overall and longer without cardiovascular disease than individuals with high-normal thyroid function.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Our study included mainly white participants older than 45 years. Therefore, it would be informative to further investigate the association of thyroid function with life expectancy in other populations. Future studies are also needed to elucidate the exact mechanisms underlying the differences in life span within the reference range of thyroid function.
Disclosures: The authors report no conflicts of interest relevant to this article.
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Bano A, Dhana K, Chaker L, Kavousi M, Ikram MA, Mattace-Raso FUS, Peeters RP, Franco OH. Association of Thyroid Function With Life Expectancy With and Without Cardiovascular DiseaseThe Rotterdam Study. JAMA Intern Med. Published online September 18, 2017. doi:10.1001/jamainternmed.2017.4836
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