A large international study has found that hormone levels in people with common adrenal tumors are much less stable than doctors once believed.
The research, published in The Lancet Diabetes & Endocrinology, shows that people whose cortisol levels stay high over many years are much more likely to develop worsening high blood pressure and other health problems linked to heart disease. The findings could change the way doctors monitor thousands of patients around the world.
The adrenal glands are two small organs that sit on top of the kidneys. Although they are small, they produce several hormones that are essential for life. One of these hormones is cortisol, often called the “stress hormone.”
Cortisol helps control blood pressure, blood sugar, metabolism, the immune system, and the body’s response to stress. Normally, the brain carefully controls how much cortisol is produced. However, sometimes a non-cancerous growth, called a benign adrenal tumor, begins making cortisol without following the body’s normal control system.
These tumors are surprisingly common. They are found by chance in about 3% to 7% of adults during scans performed for other medical reasons.
Many people never know they have one because the tumors usually cause no obvious symptoms. In some people, however, the tumor quietly produces extra cortisol. This condition is called mild autonomous cortisol secretion, or MACS.
Doctors have known that too much cortisol can increase the risk of obesity, high blood pressure, type 2 diabetes, high cholesterol, heart attack, and stroke. Until now, however, it was unclear whether cortisol levels remained stable after diagnosis or changed over time.
To answer this question, researchers from 25 specialist adrenal centers in 14 countries worked together through the European Network for the Study of Adrenal Tumors. They followed 2,525 patients with benign adrenal tumors for an average of almost seven years.
During this time, participants repeatedly underwent the standard overnight dexamethasone suppression test, which measures whether the adrenal gland continues producing cortisol when it should stop.
The results challenged long-held beliefs. About 22% of patients experienced important changes in cortisol production during follow-up, with most changes occurring during the first three years. This means that one hormone test at diagnosis may not accurately predict a person’s future hormone pattern.
The highest health risks were seen in people whose cortisol remained persistently high. Compared with people whose cortisol stayed normal, they had a 34% greater chance of worsening high blood pressure.
Over a ten-year period, they also lost around two years of well-controlled blood pressure. They carried a heavier cardiometabolic burden, meaning they were more likely to have several risk factors such as obesity, diabetes, high cholesterol, and hypertension together.
Professor Alessandro Prete explained that these findings suggest doctors should rethink long-term follow-up. Instead of assuming hormone levels remain unchanged, some patients may benefit from repeated testing, closer monitoring, and more active treatment.
Previous clinical trials have also shown that surgery to remove the adrenal tumor can improve blood pressure in selected patients with MACS.
This study has several important strengths. It included more than 2,500 patients from many countries and followed them for several years, making it the largest study of its kind. However, it cannot prove that persistently high cortisol directly caused every health problem because it was mainly observational.
Future prospective studies will help determine how often hormone testing should be repeated and which patients benefit most from surgery or other treatments. Overall, the findings provide strong evidence that long-term cortisol monitoring may improve care for people with benign adrenal tumors.
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Source: University of Birmingham.
