The epidemiology of hyperprolactinaemia over 20 years in the Tayside region of Scotland: The Prolactin Epidemiology, Audit, and Research Study (PROLEARS)

OBJECTIVE: To estimate the prevalence and incidence of hyperprolactinaemia. Hyperprolactinaemia is a common problem in endocrine practice, but its epidemiology has not been accurately established.

STUDY DESIGN: A population-based retrospective follow up study in Tayside, Scotland (population 400,000) from 1993 to 2013.

PATIENTS: Record-linkage technology (biochemistry, prescribing, hospital admissions, radiology, mortality and maternity data) was used to identify all patients with a serum prolactin measurement. From these, cases were defined as those with a prolactin greater than 1000mU/L (47.2ng/ml) or at least three prescriptions for a dopamine agonist.

MEASUREMENTS: Number of prevalent and incident cases of hyperprolactinaemia per calendar year by age, sex and cause of hyperprolactinaemia.

RESULTS: A total of 32,289 patients had a serum prolactin assay undertaken, of which 1,301 had hyperprolactinaemia not related to pregnancy: 25.6% patients were pituitary-disorder 45.9% drug-induced, 7.5% related to macroprolactin, and 6.1% related to hypothyroidism, leaving 15.0% idiopathic. Over the 20 years there was a fourfold increase in the number of prolactin assays performed and prevalence of hyperprolactinaemia was initially 0.02%, but rose to 0.23% by 2013. Overall incidence was 13.8 cases per 100,000 person-years (20.6 in 2008-13) and was 3.5 times higher in women than in men. The highest rates were found in women aged 25-44 years. Drug-induced causes tripled during the 20 years.

CONCLUSIONS: Rising prevalence of hyperprolactinaemia is probably due to increased ascertainment and increased incidence of psychoactive drug-related causes. Rates are higher in women than in men but only before the age of 65 years. This article is protected by copyright. All rights reserved.