Subclinical hyperthyroidism and sport eligibility: an exploratory study on cardiovascular pre-participation screening in subjects treated with levothyroxine for multinodular goiter.
BACKGROUND
Subclinical hyperthyroidism (sHT) affects cardiovascular (CV) morphology and function; whether such changes can impact on sport eligibility is unclear.


OBJECTIVE
This exploratory study evaluated the CV system and sport eligibility in athletes with levothyroxine-induced sHT, in the setting of mandatory pre-participation screening.


METHODS
A full, non-invasive CV screening (history and physical examination, 12-lead ECG, echocardiography, 24-hour Holter ECG, exercise stress test) was performed in two groups of untrained female athletes affected by non-toxic multinodular goiter. One group was taking levothyroxine at mildly suppressive doses (TG) whereas the other was untreated (UG). There was also a group of healthy controls (HC).


RESULTS
In TG the following characteristics were observed: a) a higher resting heart rate (HR; p<0.01 and p<0.05, vs HC and UG respectively), b) a thicker left ventricular posterior wall (p<0.05 vs HC, and p<0.05 vs HC and UG, respectively), c) a higher mean HR during the 24-hour Holter ECG (p<0.01 and p<0.05, vs HC and UG respectively), and d) a lower achieved maximum work load (p<0.05, vs HC). No differences in the prevalence of cardiac arrhythmias among groups were observed. Sport eligibility was granted to all except one subject in the TG.


CONCLUSIONS
Although some alterations were found in athletes with levothyroxine-induced mild sHT, these are probably of limited clinical relevance and they did not contraindicate sport participation in the majority of cases. Future research to address both health risks and the need for specific evaluations (e.g. free thyroxine, TSH, echocardiography) during the preparticipation screening of athletes with sHT is warranted.
Di Luigi
L
L
Unit of Endocrinology, Department of Health Sciences, University of Rome Foro Italico, piazza Lauro de Bosis, 15, 00135, Rome, Italy. luigi.diluigi@iusm.it
Parisi
A
A
Quaranta
F
F
Romanelli
F
F
Tranchita
E
E
Sgrò
P
P
Nardi
P
P
Fattorini
G
G
Cavaliere
R
R
Pigozzi
F
F
D'Armiento
M
M
Lenzi
A
A
D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology; D004452:Echocardiography; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006044:Goiter, Nodular / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood* / Q000139:chemically induced / Q000503:physiopathology; D008875:Middle Aged; D011863:Radioimmunoassay; D012307:Risk Factors; D013177:Sports; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use*; D014284:Triiodothyronine / Q000097:blood
D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine