Sex and age specific hormonal patterns in healthy Chinese individuals: a cross-sectional study of reproductive hormones

Hormonal levels change with age and impact key physiological functions. However, limited data exist on age- and sex-specific hormone reference intervals in Asian populations. This study aimed to establish normative ranges for reproductive hormones in healthy Chinese adults to support age-adjusted clinical evaluations. A cross-sectional sample of 500 healthy individuals (250 males, 250 females), aged 19-70 years, was recruited from the blood transfusion department of The Affiliated Hospital of Yangzhou University. Serum samples were collected under standardized fasting and resting conditions. Steroid hormones (testosterone, estradiol, progesterone) were measured using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS), while protein hormones (LH, FSH, prolactin) were analyzed using chemiluminescent immunoassay (CLIA). Reference intervals were derived based on IFCC guidelines. Statistical analyses included ANOVA, post-hoc Tukey tests, and t-tests. In males, testosterone showed a progressive decline with age (6.0 → 3.5 ng/mL, p < 0.001), while estradiol declined modestly (35 → 25 pg/mL).Progesterone decreased gradually (0.30 → 0.15 ng/mL, p < 0.001). LH and FSH increased significantly (4.5 → 9.5 mIU/mL and 4.0 → 16.0 mIU/mL, p < 0.001), whereas prolactin remained stable (~ 8.7 ng/mL).In females, testosterone levels were lower overall (0.40 → 0.18 ng/mL), with sharp postmenopausal declines in estradiol (110 → 20 pg/mL) and progesterone (3.5 → 0.2 ng/mL).LH and FSH rose markedly after menopause (6.5 → 32.0 mIU/mL; 7.0 → 70.0 mIU/mL, p < 0.001).Prolactin remained consistent across all ages (~ 12.7 ng/mL). This study provides sex- and age-specific hormone reference intervals for a healthy Chinese population, highlighting endocrine aging patterns and the need for age-adjusted assessment. The gradual decline of progesterone in males, of uncertain clinical significance, is noted.