Repeated serum and urinary androgen measurements in premenopausal and postmenopausal women

Intra-individual variability for serum and urinary hormones has been inadequately considered in previous studies. Therefore, in the planning phase of a prospective study of Hormones and Diet in the Etiology of Breast Cancer (ORDET study), androgen levels have been examined at two different times in 56 women (26 in premenopause and 30 in postmenopause). Hormonal measurements in serum showed a good level of agreement for both premenopause (pre) and postmenopause (post): androstenedione pre r = 0.70 (p <0.0001), post r = 0.77 (p <0.0001); testosterone pre r = 0.73 (p <0.0001), post log values r = 0.74 (p <0.0001). Dihydrotestosterone showed a good level for premenopause only: log values pre r = 0.82 (p <0.0001), post r = 0.41 (p <0.05). Agreement levels in urine were inferior to those of serum: testosterone pre r = 0.53 (p <0.05), post r = 0.41 (p <0.05); androstanediol log values r = 0.46 (p <0.001), post log values r = 0.57 (p <0.05). Correlation between the two measurements improves considering age, parity, time of blood collection and, for urine, the interval of sample collections.