The Dehydroepiandrosterone And WellNess (DAWN) study: Research design and methods

Abstract

Levels of dehydroepiandrosterone (DHEA) and DHEA-sulfate (DHEAS), the major secretory products of the adrenal gland, decline dramatically with age, concurrent with the onset of degenerative changes and chronic diseases associated with aging. Epidemiological evidences in humans and animal studies suggest that DHEA(S) may have cardioprotective, antiobesity, antidiabetic, and immuno-enhancing properties. These observations led to the proposal that restoration of DHEA to young adult levels may have beneficial effects on age-related conditions. Most clinical trials of DHEA replacement have been limited due to small samples and short duration, restriction to one sex, failure to adjust for baseline endogenous hormone level and age, or lack of placebo comparison groups. We designed a double blind, placebo-controlled randomized trial to determine the acceptability, benefits, and adverse effects of 50 mg daily oral DHEA replacement for one year in 110 men and 115 women, aged 55 to 85, who were healthy and not currently using hormone therapy. A wide range of biological outcomes were studied including bone mineral density and metabolism, body composition and muscle strength, immune function, and cardiovascular risk factors. Steroid hormone levels, bone markers, cytokines, and the IGF-I, IGF binding protein system were measured at baseline and at 3 follow-up clinic visits. Changes in mood and well-being, cognitive function, and sexuality were assessed. Information on potentially confounding covariates such as smoking, alcohol consumption, exercise, diet and dietary supplements were obtained, and potential adverse effects of DHEA administration were monitored. This study enables an examination of the benefits of DHEA administration on the health of older men and women, and the influence of gender, age, and baseline endogenous DHEA level on each outcome variable. Potential mechanisms of DHEA action, including the biotransformation of DHEA to active steroids and steroid metabolites, enhancement of IGF-I bioavailability, and inhibition of IL-6 production can also be evaluated.