Typically veins are generally wider than arteries, and therefore the pressure is lower. Capillaries are tiny vessels, so repsent high resistance to the incoming blood, so the rate of blood flow through will be quite low. All blood from the artery eventually passes through capillaries and into the vein.
Graves' disease. Graves' disease is the most common cause of overactive thyroid. It can run in families and can occur at any age, although it is most common in women aged 20-40 years old. You are more likely to develop Graves' disease if you smoke. Graves' disease is an autoimmune condition.
Other causes of an overactive thyroid can include inflammation of the thyroid due to viruses or bacterial infections. Also, postpartum hyperthyroidism affects women immediately after pregnancy. This is one of the most common postpartum health disorders, and it affects between ten and twenty percent of women.