Adrenal incidentalomas constitute a common clinical problem with an overall prevalence of around 2-3%, but are more common with advancing age being present in 10% of those aged 70 years. The majority of these lesions are benign
adrenocortical adenomas (80%), characterized in 10-40% of the cases by autonomous
cortisol hypersecretion, and in 1-10% by
aldosterone hypersecretion. Several observational studies have shown that autonomous
cortisol and
aldosterone hypersecretion are more prevalent than expected in patients with
osteopenia and
osteoporosis: these patients have accelerated bone loss and an increased incidence of vertebral fractures. In contrast to
glucocorticoid action, the effects of
aldosterone on bone are less well understood. Recent data, demonstrating a concomitant co-secretion of
glucocorticoid metabolites in patients with primary
aldosteronism, could explain some of the metabolic abnormalities seen in patients with
aldosterone hypersecretion. In clinical practice, patients with unexplained
osteoporosis, particularly when associated with other features such as
impaired glucose tolerance or
hypertension, should be investigated for the possible presence of autonomous
cortisol or
aldosterone secretion due to an adrenal
adenoma. Randomized intervention studies are needed, however, to investigate the optimum interventions for
osteoporosis and other co-morbidities in these patients.