Current risk factors for male infertility and semen parameters: an umbrella review of systematic reviews and meta-analyses.
Level 1 - systematic review of randomized trials
Systematic review of systematic reviews and meta-analyses (umbrella review)
PubMed 41527944 · doi:10.4103/aja202552
What was done
Authors conducted an umbrella review searching Web of Science, MEDLINE, and Embase (January 2000 to February 2025) for systematic reviews and meta-analyses examining risk factors for male infertility and abnormal semen parameters (volume, concentration, count, morphology, motility, and progressive motility). Evidence certainty for each association was scored using GRADE.
What was found
The review included 43 systematic reviews encompassing 67 risk factors and 249 individual effect sizes. GRADE scoring categorized 136 effect sizes (54.6%) as very low certainty, 59 (23.7%) as low certainty, and 54 (21.7%) as moderate certainty; zero were classified as high certainty. Decreased semen quality or increased infertility risk was linked to metabolic and inflammatory conditions (type 1 diabetes, metabolic syndrome, hyperthyroidism, systemic lupus erythematosus, chronic prostatitis, leukocytospermia), lifestyle factors (obesity, sleep disorders, smoking), environmental pollutants (carbon disulfide, organophosphates, lead), medications (sulfasalazine, mesalazine, SSRIs), and viral infections (SARS-CoV-2, HPV, hepatitis). Physical exercise, nut intake, and healthy diets were positively associated with semen quality. Specific numeric effect estimates and confidence intervals were not reported in the abstract.
Why it matters
This umbrella review maps the broad landscape of proposed risk factors for male subfertility and highlights that over three-quarters of identified associations rest on low- or very-low-quality evidence that lacks definitive causal verification.
Limits
The abstract provides no quantitative effect sizes, odds ratios, or confidence intervals. Total individual participant sample sizes and primary study overlap among the 43 reviews are not reported. Causality cannot be established due to the predominantly observational nature of the underlying literature.
Cited by
- supports Insulin resistance, metabolic disease, and obesity are the primary modifiable risk factors driving the decline in male fertility and sperm parameters.