SAN DIEGO — A long-term study of dehydroepiandrosterone supplementation in elderly men and women found no effect on body composition, muscle strength or performance, glucose metabolism, or quality of life.
There was a “trend … of borderline significance” for the effect of the popular supplement on bone mineral density, which was the only positive finding that approached statistical significance in the 2-year study, said K. Sreekumaran Nair, M.D., professor of endocrinology at the Mayo Medical School in Rochester, Minn.
Dr. Nair presented results of one of the few well-designed, long-term studies of dehydroepiandrosterone (DHEA) supplementation at the annual meeting of the Endocrine Society.
To provide an objective, long-term perspective, Dr. Nair and associates recruited 120 men and women (mean age, 69 and 70 years, respectively) with low dehydroepiandrosterone sulfate (DHEAS) levels, defined as concentrations below the 15th percentile for normal young adults. In men, bioavailable testosterone was also low, falling more than 1.5 standard deviations below the mean.
Eligible participants were randomized to receive supplemental DHEA (50 mg/day for women and 75 mg/day for men) or placebo for 20–24 months.
As expected, individuals taking DHEA had significant increases in DHEAS levels. Estradiol levels also rose significantly in both women and men taking DHEA. In women only, testosterone levels increased significantly, from a mean 30 ng/dL to a mean 45 ng/dL.
At enrollment and upon completion of the study, researchers conducted a wide variety of tests to identify any potential changes in muscle function, fat distribution, and carbohydrate metabolism. These tests included maximum oxygen consumption, chest press, isometric and double-knee extension, thigh muscle mass by single-slice CT, and fat-free mass by DXA to evaluate muscle function, ratio of visceral to total fat to characterize fat distribution, and fasting glucose and insulin for carbohydrate metabolism. Also measured was bone mineral density at the L2-L4 spine, femur neck, total hip, distal radius, and ultradistal radius.
Quality of life was assessed by using both physical and mental competency scores. Dr. Nair ticked through the results methodically, demonstrating “no difference at all” in subjects taking DHEA vs. placebo on myriad measures. “Body fat-free mass? The same story,” he said at one point.
Bone mineral density did improve slightly in subjects who were taking DHEA, compared with those taking placebo, mainly due to a 5.7% relative increase in ultradistal forearm BMD in women and a 2.6% relative increase in femur neck BMD in men. But Dr. Nair characterized the overall trend in BMD as “weak” evidence of DHEA's effectiveness.
On a more positive note, no adverse effects were associated with taking DHEA long term, Dr. Nair said during a symposium at the meeting.