Hypothyroidism or underactive thyroid gland is an endocrine condition where the thyroid gland fails to produce sufficient levels of thyroid hormones.
Hypothyroidism can affect any individual at any age but there are some risk factors that increase the likelihood of this condition developing. These risk factors are described below.
- Gender – Although hypothyroidism may affect men or women, it is more common among females and in the UK, this disease affects 1.5% of women compared with only 0.1% of men.
- Age – Hypothyroidism is more likely to develop after the age of 60. The American Thyroid Association suggests that all adults (especially women) over the age of 35 years should have a routine blood test to check their thyroid function every 5 years.
- People who have previously been treated with radioactive iodine therapy to the neck or upper chest are at an increased risk of hypothyroidism.
- People who have previously undergone thyroid surgery are also at an increased risk.
- Family history of autoimmune disease – People with a close relative (e.g. parent or grandparent) who suffers form an autoimmune disease are more at risk.
- Other autoimmune disease – People who already have another immune condition are at an increased risk. Examples of these conditions include pernicious anemia, type 1 diabetes, rheumatoid arthritis, vitiligo, celiac disease, multiple sclerosis, and Addison’s disease. These individuals need to be checked for hypothyroidism more frequently than individuals who do not have these conditions.
- Girls and women who have Turner syndrome (more than two X chromosomes) are at a greater risk of hypothyroidism.
- Down syndrome is anther genetic condition that increases the risk of hypothyroidism developing.
- Women who have delivered a baby within the past six months should be screened routinely for hypothyroidism, especially if they have symptoms of an underactive thyroid.
- Ethnicity – Hypothyroidism is more common among Asian and white individuals than it is among other races.
- Medications – Certain medications also cause hypothyroidism as a side effect. Examples include lithium (a mood stabilizer user to treat depression and bipolar disorder), amiodarone (a drug used to treat arrhythmia or irregular heartbeat) and interferon (used to treat hepatitis C and some types of cancer).
Reviewed by Sally Robertson, BSc