Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

The purpose of this study was to assess pituitary gonadotropins and free testosterone levels in a larger cohort of men with Alzheimer's disease (AD, n=112) and age-matched controls (n=98) from the Oxford Project to Investigate Memory and Ageing (OPTIMA). We measured gonadotropins (follicle stimulating hormone, FSH, and luteinizing hormone, LH), sex hormone binding globulin (SHBG, which determines the amount of free testosterone) and total testosterone (TT) using enzyme immunoassays. AD cases had significantly higher LH and FSH and lower free testosterone levels. LH, FSH and SHBG all increased with age, while free testosterone decreased. Low free testosterone was an independent predictor for AD. Its variance was overall explained by high SHBG, low TT, high LH, an older age and low body mass index (BMI). In controls, low thyroid stimulating hormone levels were also associated with low free testosterone. Elderly AD cases had raised levels of gonadotropins. This response may be an attempt to normalize low free testosterone levels. In non-demented participants, subclinical hyperthyroid disease (a risk factor for AD) which can result in higher SHBG levels, was associated with low free testosterone. Lowering SHBG and/or screening for subclinical thyroid disease may prevent cognitive decline and/or wasting in men at risk for AD.

Original publication




Journal article


Exp Gerontol

Publication Date





1633 - 1639


Aged, Alzheimer Disease, Body Mass Index, Case-Control Studies, Cross-Sectional Studies, Follicle Stimulating Hormone, Humans, Hyperthyroidism, Luteinizing Hormone, Male, Middle Aged, Risk Factors, Sex Hormone-Binding Globulin, Statistics, Nonparametric, Testosterone, Thyrotropin