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Umbrella review identifies risk factors and protective factors for male infertility and semen qualityNew study lists many things that hurt male fertility and health

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Key Takeaway
Consider counseling male patients on modifiable risk factors like obesity, smoking, and medications, but recognize most evidence is low certainty.

This umbrella review of systematic reviews and meta-analyses, covering 43 studies from Web of Science, MEDLINE, and Embase (January 2000 to February 2025), synthesizes evidence on risk factors for male infertility and abnormal semen parameters. The review examined a wide range of exposures including lifestyle habits, pollutants, medications, viral infections, and healthy behaviors.

Key findings indicate increased risk of abnormal semen parameters associated with type 1 diabetes, metabolic syndrome, hyperthyroidism, systemic lupus erythematosus, chronic prostatitis, and leukocytospermia. Decreased semen quality was linked to poor lifestyle habits (obesity, sleep disorders, smoking), exposure to pollutants (carbon disulfide, organophosphates, lead), medications (sulfasalazine, mesalazine, selective serotonin reuptake inhibitors), and viral infections (SARS-CoV-2, HPV, hepatitis viruses). Conversely, regular physical exercise, nut consumption, and adherence to a healthy dietary pattern were associated with reversal of decreased semen quality.

Importantly, the authors note that some of the included studies lack verification of causal relationships. Certainty of evidence was assessed using GRADE: of 249 effect sizes, 136 (54.6%) were classified as 'very low', 59 (23.7%) as 'low', and 54 (21.7%) as 'moderate'. No effect sizes were reported for pooled estimates, and safety outcomes were not reported.

Clinicians should interpret these findings cautiously given the predominantly low to very low certainty evidence. The review highlights potentially modifiable risk factors and protective behaviors, but causal inferences are limited by the observational nature of the underlying studies.

Imagine a man trying to start a family. He visits the doctor because he cannot get pregnant. The doctor looks at his health history. The doctor also checks his sperm count. The results are not good. This situation is very common.

Male infertility is a big problem. It hurts the lives of many couples. It also puts stress on families. Doctors have studied this issue for a long time. They found many things that make sperm work poorly.

But the old way of thinking is changing. We used to blame just one thing. Now we see a list of causes. Some causes are easy to fix. Others need medical help. This new research gives us a clear map.

The body has a factory inside. It makes millions of tiny swimmers every day. Think of this factory like a busy kitchen. If you eat junk food, the kitchen gets messy. If you smoke, the air gets smoky. If you have a disease, the workers get sick. All of this lowers the quality of the final product.

Here is what the new research found. The team looked at hundreds of studies. They checked data from the last twenty five years. They found sixty seven different risk factors. These factors can hurt sperm volume, count, and movement.

Some health conditions make things worse. Type one diabetes is one example. Metabolic syndrome is another. Hyperthyroidism and lupus also play a role. Chronic prostatitis and high white blood cells in semen are bad too. These conditions create a bad environment for sperm.

Bad habits also hurt the factory. Obesity is a major problem. Sleep disorders stop the body from resting. Smoking damages the cells directly. Exposure to pollutants like lead or carbon disulfide is also dangerous. Even some viruses can lower sperm quality.

This doesn't mean this treatment is available yet.

The good news is that some things help. Regular physical exercise is powerful. Eating nuts is very beneficial. A healthy diet pattern works well too. These actions can reverse the damage. They help the factory run better again.

The study included forty three different papers. They covered many risk factors. The team used a special tool to grade the evidence. Some findings were very strong. Others needed more proof. This is normal for science.

We must be careful with what we say. We cannot say these habits cause infertility for sure. We can only say they are linked. More research is needed to prove the links. We need better designed studies in the future.

What does this mean for you? Talk to your doctor. Ask about your lifestyle. If you smoke, try to quit. If you are overweight, start moving. Small changes make a big difference. Do not wait until you have a problem.

The road ahead is clear. We need more trials. We need to confirm these relationships. It takes time for new treatments to appear. Be patient with the science. Stay hopeful about your health.

Study Details

Study typeMeta analysis
EvidenceLevel 1
PublishedMay 2026
View Original Abstract ↓
Male infertility poses a substantial healthcare challenge and severely impacts the lives of patients. We aimed to investigate the risk factors for infertility and abnormal semen parameters. We conducted a comprehensive search of the articles published in Web of Science, MEDLINE, and Embase databases from January 2000 to February 2025. Infertility, semen volume, sperm concentration, sperm count, sperm morphology, sperm motility, and sperm progressive motility were used as endpoints to evaluate the relevance of risk factors. A total of 43 studies were included, covering 67 risk factors associated with infertility and abnormal sperm parameters. A total of 249 effect sizes were scored individually using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool, of which 136 (54.6%) were classified as "very low", 59 (23.7%) as "low", and 54 (21.7%) as "moderate". Suffering from type 1 diabetes, metabolic syndrome, hyperthyroidism, systemic lupus erythematosus, chronic prostatitis, and leukocytospermia may increase the risk of abnormal semen parameters. Poor lifestyle habits (obesity, sleep disorders, and smoking), exposure to pollutants and various compounds (carbon disulfide, organophosphates, and lead), the use of medications (sulfasalazine, mesalazine, and selective serotonin reuptake inhibitors), and even some viral infections (severe acute respiratory syndrome coronavirus 2, human papillomavirus, and hepatitis viruses) were associated with decreased semen quality. Regular physical exercise, nut consumption, and adherence to a healthy dietary pattern may reverse this process. An increasing number of factors are associated with infertility; however, some of the aforementioned studies lack verification of causal relationships. Future studies need to be well designed to further confirm these relationships.
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