Up to 10 per cent of adults have a benign tumor, or lump, known as an ‘adrenal incidentaloma’ in their adrenals – glands situated on top of the kidneys which produce a variety of hormones. The lumps can be associated with the overproduction of hormones including the stress steroid hormone cortisol, which can lead to type 2 diabetes and high blood pressure. Previous small studies suggested that one in three adrenal incidentalomas produce excess cortisol, a condition called Mild Autonomous Cortisol Secretion (MACS).
Now, an international research team led by the University of Birmingham in the UK has carried out the largest ever prospective study of over 1,305 patients with adrenal incidentalomas to assess their risk of high blood pressure and type 2 diabetes and their cortisol production, comparing patients with and without MACS. The study is also the first to undertake a detailed analysis of the steroid hormone production in patients by analyzing cortisol and related hormones by mass spectrometry in 24-hour urine samples they collected.
Their study findings, published today in journal Annals of Internal Medicine, show that MACS is much more prevalent than previously reported: with almost every second patient in the study with an adrenal incidentaloma having MACS. Notably, 70% of patients with MACS were women and most of them were of postmenopausal age (aged over 50). Following their findings, the researchers now estimate that up to 1.3 million adults in the UK could have MACS. Considering that around two out of three of these patients are women, MACS is potentially a key contributor to women’s metabolic health, in particular in women after the menopause.