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Hashimoto thyroiditis is an independent cardiovascular risk factor in clinically hypothyroid patients
Abstract
cause of hypothyroidism and cardiovascular risk.
Subjects and methods: The study included 20 patients with Hashimoto thyroiditis and hypothyroidism, 20 patients with post-thyroidectomy hypothyroidism, 20 patients with post-radioiodine hypothyroidism,
and 20 age and sex matched controls. In all the studied subjects we determined thyroid function tests; TSH and F.T4, thyroid auto-antibodies; anti-TPO and anti-TG antibodies, carotid intima media thickness (CIMT), flow mediated dilation (FMD) and serum nitric oxide.
Results: CIMT showed a trend to be higher in HT group (0.93± 0.08 mm) compared to other causes of hypothyroidism (P = 0.090). Multivariate analysis showed that HT is an independent predictor of CIMT (P = 0.015). FMD was significantly lower in HT group (5.74± 1.33%) compared to post-thyroidectomy (7.16± 1.05%) (P = 0.001), and post-radioiodine therapy (7.34 ±1.34%) (P = 0.000). Multivariate analysis showed that HT is an independent predictor of FMD (P =0.000). NO was significantly higher in hypothyroid patients (125.98 ± 5.03 lM/ml) compared to controls (39.44± 3.63 lM/ml) (P =0.001), both univariate and multivariate
analyses showed that NO is an independent predictor of both CIMT and FMD (P = 0.000).
Conclusion: To our knowledge, this is the first study to show that Hashimoto thyroiditis is an independent cardiovascular risk factor in clinically hypothyroid patients.