Is subclinical hypothyroidism a risk factor for myocardial infarction? A comparative study of a cohort of young Pakistani men

Aim: Myocardial infarction (MI) is a major cause of death globally with a rising incidence at a younger age. Subclinical hypothyroidism (SCH) is an asymptomatic condition with raised serum thyroid-stimulating hormone (TSH) and normal free thyroid hormones. SCH has been linked with MI previously, but local data are not available. The present study was done to determine the relation between SCH and MI in young men from the local population. Material and Methods: The cross-sectional study compared male patients with MI (n=75) with age-matched controls (n=75) for the presence of subclinical hypothyroidism and other clinical risk factors including blood pressure, waist circumference and fasting blood glucose (FBG). For the assessment of SCH, serum thyroid hormone profile was done, including TSH, free tri -iodothyronine (fT3) and free thyroxine (fT4) levels. Results: The incidence of SCH in MI patients and healthy control subjects were 12% and 5%, with the difference being statistically insignificant (p=0.15.). No differences were observed between the two groups in thyroid hormone profile and other clinical risk factors studied. Discussion: SCH does not appear to be associated with an increased risk of MI in local population of Pakistani men. Considering the study limitations, larger prospective trials are warranted to inform robust outcomes.