The Study
Age-related changes in serum reproductive hormone levels and prevalence of androgen deficiency in Chinese community-dwelling middle-aged and aging men
This study looked at how hormone levels change as men get older, but it didn't follow the same men over time. It's like taking a photo of a group of people at different ages and saying 'older people have lower energy'—but we don't know if aging caused it, or if other things like diet or exercise made the difference.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Scientists studied two groups of Chinese men to see how their hormone levels change as they get older.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 544 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes—this means many older men may have low active testosterone even if their total testosterone looks normal, which could affect energy, muscle, and mood.
- 2Free testosterone (the active kind) dropped by about 1–3 pmol per year as men aged; total testosterone didn’t drop consistently—it even went up in one group.
- 3The older the man, the more likely he was to have low free testosterone: from 1.2% in 40–44 year-olds to 61.6% in 65–69 year-olds.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Medicine
Year
2020
Authors
Shan-Jie Zhou, Mingjia Zhao, Yi-Hong Yang, D. Guan, Zhi-Guang Li, Yu-dang Ji, Bao-long Zhang, X. Shang, C. Xiong, Yi-qun Gu
Related Content
Claims (6)
In Chinese men aged 40 to 69, the percentage diagnosed with androgen deficiency differs significantly depending on whether doctors measure total testosterone or calculate free testosterone.
In two different groups of Chinese adults, the level of testosterone in the blood changed differently with age—one group showed an increase, the other showed no change—because of differences in how testosterone was measured or in the characteristics of the populations studied.
In Chinese men between 40 and 69 years old, free testosterone levels decrease by 1.06 to 2.71 pmol/L each year as they age, and the percentage of men with androgen deficiency rises from 1.2% to 61.6% across these age groups.
In Chinese men between 40 and 69 years old, higher levels of sex hormone-binding globulin in the blood are linked to lower levels of free testosterone.
Between 1972 and 2019, the average testosterone level in men dropped by 54%, which equals more than a 1% decrease each year.
In Chinese men, the level of free testosterone calculated from blood tests rises with age, while total testosterone levels do not change, making free testosterone a better indicator of age-related androgen deficiency.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.