Several series of data suggest that alterations in adrenal androgen output might be a contributing factor to changes in bone mass. To study the possible relationship between bone density and serum levels of dehydroepiandrosterone sulphate (DHEAS) we investigated 105 women (aged 45-69 years; 76 postmenopausal, 29 perimenopausal). The patients were divided into two groups according to the bone mineral density (BMD) measurement (normal density n = 50, low density n = 55). BMD was measured by dual-energy X-ray absorptiometry of the lumbar spine and femoral neck. Bone mineral content (BMC) of the radius midshaft was measured by single photon absorptiometry. Serum DHEAS level was significantly lower in the 'low density' group than in the 'normal' one (1.91 +/- 1.04 v 4.77 +/- 2.03 mumol/l, p < 0.001). The serum DHEAS level decreased significantly with age in both groups (r = 0.43, p < 0.001 in the 'normal' group; r = 0.35, p < 0.01 in the 'low density' group). Unlike the slopes, the positions of the regression lines differed significantly (difference 2.85 mumol/l, p < 0.001). Correcting for age by multiple linear regression we established a significant positive relationship between DHEAS and BMD of the lumbar spine and femoral neck, and BMC of radius midshaft as well. Since there was no significant difference between the two groups regarding oestrogens, we suggest that DHEAS may have a non-oestrogenic effect on bone. The odds ratio of a subject with a low (< 3.3 mumol/l) serum DHEAS level having low BMD was 40 (confidence interval 13-126).(ABSTRACT TRUNCATED AT 250 WORDS)