Thyroid hormones and mortality risk in euthyroid individuals: the Kangbuk Samsung health study

Yiyi Zhang, Yoosoo Chang, Seungho Ryu, Juhee Cho, Won-Young Lee, Eun-Jung Rhee, Min-Jung Kwon, Roberto Pastor-Barriuso, Sanjay Rampal, Won Kon Han, Hocheol Shin, Eliseo Guallar
Journal of Clinical Endocrinology and Metabolism 2014, 99 (7): 2467-76

CONTEXT: Hyperthyroidism and hypothyroidism, both overt and subclinical, are associated with all-cause and cardiovascular mortality. The association between thyroid hormones and mortality in euthyroid individuals, however, is unclear.

OBJECTIVE: To examine the prospective association between thyroid hormones levels within normal ranges and mortality endpoints.

SETTING AND DESIGN: A prospective cohort study of 212 456 middle-aged South Korean men and women who had normal thyroid hormone levels and no history of thyroid disease at baseline from January 1, 2002 to December 31, 2009. Free T4 (FT4), free T3 (FT3), and TSH levels were measured by RIA. Vital status and cause of death ascertainment were based on linkage to the National Death Index death certificate records.

RESULTS: After a median follow-up of 4.3 years, 730 participants died (335 deaths from cancer and 112 cardiovascular-related deaths). FT4 was inversely associated with all-cause mortality (HR = 0.77, 95% confidence interval 0.63-0.95, comparing the highest vs lowest quartile of FT4; P for linear trend = .01), and FT3 was inversely associated cancer mortality (HR = 0.62, 95% confidence interval 0.45-0.85; P for linear trend = .001). TSH was not associated with mortality endpoints.

CONCLUSIONS: In a large cohort of euthyroid men and women, FT4 and FT3 levels within the normal range were inversely associated with the risk of all-cause mortality and cancer mortality, particularly liver cancer mortality.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"