High elevation linked to hormone dearth

Elderly Peruvian women living at high elevations have lower concentrations of a natural steroid in their blood than their sea-level counterparts do, a study shows. This shortage might place the mountain women at risk of illness and could explain, in part, earlier reports that women living at extreme altitudes have shorter life spans than lowland women do.

The researchers compared blood samples from women living at elevations above 4,000 meters in the Andes with samples from women of similar ethnicity living near sea level in Lima. Between the ages of 60 and 70, the mountain women had less than half as much dehydroepiandrosterone (DHEA) in their blood as the Lima women had, the authors report in the April Journal of Endocrinology. The mountain women also had lower blood concentrations of two related hormones, DHEA sulfate and androstenedione, says study coauthor Gustavo F. Gonzales, an endocrinologist at the University of Peruana Cayetan Heredia in Lima.

Concentrations of these hormones decline naturally with age. The high elevation might accelerate that natural aspect of aging, says Gonzales.

Made by the adrenal glands, DHEA is the most abundant steroid in the bloodstream. It can be converted into androstenedione, which is a precursor for both testosterone and estrogen, the main sex hormones in men and women, respectively. In women, this concert of hormones maintains bone, builds muscle mass, and boosts energy.

The study is “straightforward and original,” says Lo Chang Ou, a physiologist at Dartmouth Medical School in Lebanon, N.H. It supports a correlation between high altitude and a pattern of low hormone concentrations. However, since the functions of the three hormones aren’t fully understood, it’s impossible to say whether a dearth directly predisposes women to particular diseases and results in early death, he says.

Synthetic DHEA is sold as a dietary supplement in the United States. But, “it is too early to suggest treatment” of the mountain women with DHEA, Gonzales says. Previous studies of people living at high elevations found shrinkage in the part of the adrenal glands that makes DHEA, he and his colleagues note.