Effects of age on serum dehydroepiandrosterone sulfate, IGF-I, and IL-6 levels in women

Data from animal and in vitro studies suggest that the growth-promoting eff ects of the adrenal androgen dehydroepiandrosterone sulfate (DHEAS) may be mediated by stimulation of insulin-like growth factor-I (IGF-I) and/or inhi bition of interleukin 6 (IL-6), a cytokine mediator of bone resorption. Thi s study tests the hypotheses that there are effects of age on serum DHEAS, IGF-I, and IL-6 levels, and that levels of IGF-I and IL-6 are related to DH EAS levels. The study included 102 women: 27 premenopausal and 75 postmenop ausal, including 35 postmenopausal women with osteoporosis, as defined by b one mineral density scores by dual X-ray energy absorptiometry. DHEAS level s decreased significantly with age (r = -0.52, P < 0.0001) and IGF-I levels decreased significantly with age (r = -0.49, P < 0.0001). IL-6 levels incr eased significantly with age (r = 0.36, P = 0.008). IGF-I was positively co rrelated to DHEAS levels (r = 0.43, P < 0.0001, n = 102) and IL-6 levels we re negatively correlated to DHEAS levels (r = -0.32, P = 0.021, n = 54). Le vels of DHEAS and IGF-I were correlated with T scores of the spine and some hip sites. In a multiple Variable model to predict DHEAS, age was an impor tant predictor (P < 0.001), but osteoporosis status, IGF-I, and IL-6 were n ot. The median DHEAS level was lower in the postmenopausal osteoporotic wom en (67 mu g/dl, n = 35) than in the nonosteoporotic postmenopausal women (1 06.3 mu g/dl, n = 40, P = 0.03), but this was not significant after correct ion for age. Age accounted for 32% of the variance in DHEAS levels. In summ ary, DHEAS levels decreased with age and had a positive association with IG F-I levels and a negative association with IL-6 levels. DHEA deficiency may contribute to age-related bone loss through anabolic (IGF-I) and antiosteo lytic (IL-6) mechanisms.