Cross SectionalHumann = 33362026China

Modifiable key factors and semen quality in men undergoing preconception evaluation: a cross-sectional study.

Journal: Asian journal of andrologyPublished: 2026DOI: 10.4103/aja20263

Plain-language summary

This study set out to examine how modifiable lifestyle factors like smoking, drinking, and weight affect semen quality in men. It analyzed data from over 3,300 men visiting a fertility clinic in China, looking at their habits and semen test results while accounting for age, abstinence time, and season. Smoking more than 20 cigarettes a day or for over 10 years was linked to worse sperm counts and motility, while former drinkers saw only slight improvements in motility. Weight had a complex tie to semen quality, with some measures peaking in mildly overweight men but obesity still tied to poorer results, suggesting that even small weight changes may help.

Key findings

  • Smoking more than 20 cigarettes a day or for over 10 years was linked to lower sperm counts, total sperm, and movement.
  • Former drinkers had only small improvements in sperm movement.
  • Weight showed a complex tie to sperm health, with some measures peaking in mildly overweight men but obesity still harming sperm quality.

How to analyze the study yourself

Study type
Cross-sectional studies are good at spotting links at one point in time but cannot prove cause and effect.
Population
Men attending a preconception clinic in China.
Funding
Not reported
Watch for
This study found that heavy smoking and obesity were linked to poorer semen quality, while even modest weight changes might help. If you are trying to conceive, cutting back on smoking and managing your weight may be worth it.