According to the American Heart Association, 90% to 95% of high blood pressure cases have no identifiable cause. This type of high blood pressure is called essential hypertension.
For the remaining 5% to 10% of cases, called secondary hypertension, possible factors include:
- kidney abnormalities or chronic kidney disease
- congenital narrowing of the aorta or other arteries
- thyroid disease
- sleep apnea
Certain medications can also raise blood pressure. These include asthma medicines (such as corticosteroids), decongestants and other cold-relief products, birth control pills, and hormone replacement therapy.