Andrology. 2023 Jan 28. doi: 10.1111/andr.13396. Online ahead of print.
ABSTRACT
BACKGROUND: Since the 1970s, several studies found that sperm concentration (SC) and total sperm count (TSC) constantly worsened over time, mainly in high-income countries.
OBJECTIVES: To evaluate whether the decreasing trend in sperm count is continuing in Western European countries and USA, we performed a systematic review and meta-regression analysis.
MATERIALS AND METHODS: Embase and Pubmed/Medline were searched for papers published in English in the 2000-2020 period limiting the search to data collected in the USA and in Western European countries.
RESULTS: We identified 62 articles and pooled information on 24,196 men (range 10-2,523), collected from 1993 to 2018. Considering all the studies, random-effects meta-regression analyses showed no significant trend for SC (slope per year -0.07 mil/mL, p-value = 0.86). Negative trends of SC were detected in Scandinavian countries (slope per year -1.11 mil/mL, 95%CI: -2.40 to +0.19; p-value = 0.09), but the findings were statistically not significant. No significant trends of SC were detected in Central Europe (slope per year +0.23, 95%CI -2.51 to +2.96; p-value = 0.87), the USA (slope per year +1.08, 95%CI -0.42 to +2.57; p-value = 0.16) and Southern Europe (slope per year +0.19, 95%CI -0.99 to +1.37; p-value = 0.75). We have analysed separately findings from studies including sperm donors, fertile men, young unselected men (unselected men, study mean age<25 years) and unselected men (unselected men, study mean age≥25 years). No significant trends of SC were observed among sperm donors (slope per year -2.80, 95%CI -6.76 to +1.17; p-value 0.16), unselected men (slope per year -0.23, 95%CI -1.58 to +1.12; p-value 0.73), young unselected men (slope per year -0.49, 95%CI -1.76 to +0.79; p-value 0.45), fertile men (slope per year +0.29, 95%CI -1.09 to +1.67; p-value 0.68).
DISCUSSION AND CONCLUSION: The results of this analysis show no significant trends in SC in USA and selected Western European countries. This article is protected by copyright. All rights reserved.
PMID:36709405 | DOI:10.1111/andr.13396
