Subclinical hypothyroidism (SCH), cardiovascular risk and quality of life

INTERVENTION: Double blind randomised controlled crossover study using thyroxine (100 mcg/day) versus placebo. CONDITION: Subclinical hypothyroidism ; Nutritional, Metabolic, Endocrine ; Subclinical hypothyroidism PRIMARY OUTCOME: Improvement in brachial artery Flow Mediated Dilatation (FMD) as a marker of vascular endothelial function and Total Cholesterol (TC) levels, after 12 weeks of L‐thyroxine treatment. SECONDARY OUTCOME: Changes in:; 1. Health status; 2. Quality of life; 3. Weight as assessed by body mass index; 4. Waist circumference and waist hip ratio; 5. Blood pressure; 6. Triglyceride; 7. High Density Lipoprotein (HDL) cholesterol; 8. Low Density Lipoprotein (LDL) cholesterol; 9. Apolipoprotein A1 and apolipoprotein B; 10. Serum markers of endothelial function (e‐selectin, soluble adhesion molecule 1, tissue plasminogen activator and plasminogen activator inhibitor 1) and markers of inflammation high sensitive C‐reactive protein INCLUSION CRITERIA: 1. Subjects from Primary Care (general practices) 2. Aged 18 to 80 years of age 3. Who have at least two abnormal thyroid function tests