Age and menopausal status are important factors influencing the serum human epididymis secretory protein 4 level: a prospective cross-sectional study in healthy Chinese people.

Background: Human epididymis secretory protein 4 (HE4) is a new ovarian cancer biomarker. The factors influencing HE4 levels are not clear, and the reference data in China are limited. Here, we aim to evaluate the effects of menopause and age on HE4 levels and to provide a possible reference value for HE4 in healthy Chinese people.

Methods: A total of 2493 healthy females aged 40 years or older were recruited from March 2013 to March 2017 with the cooperation of four medical institutions across Beijing, China. The serum levels of HE4 and cancer antigen 125 (CA125) were measured by enzyme-linked immunosorbent assay. The Wilcoxon rank-sum test of variance and a stratified analysis were used to analyze the relationships among age, menopausal status, and levels of HE4 or CA125. Confidence intervals (5%-95%) were determined for reference ranges in different populations.

Results: There was a statistically significant difference in median HE4 levels between the post-menopausal (n = 2168) and pre-menopausal groups (n = 325) (36.46 vs. 24.04 pmol/L, Z = -14.41, P < 0.001). HE4 increased significantly with age in the post-menopausal groups (H = 408.18, P < 0.001) but not in the pre-menopausal subjects (Z = -0.43, P = 0.67). The upper 95th percentile of HE4 levels were 44.63 pmol/L for pre-menopausal women, 78.17 pmol/L for post-menopausal women, and 73.3 pmol/L for all women. In the post-menopausal population, the HE4 reference ranges were 13.15 to 47.31, 14.31 to 58.04, 17.06 to 73.51, 24.50 to 115.25, and 35.71 to 212.37 pmol/L for different age groups from forty divided by decade. The CA125 level was affected mainly by menopausal status and not age.

Conclusions: Menopausal status and age were both important factors influencing the level of HE4, and age affected HE4 levels mainly in post-menopausal women. The HE4 level was higher in the post-menopausal population than in the pre-menopausal population and increased with age.