Factor V Leiden is associated with increased sperm count

AbstractSTUDY QUESTIONIs the thrombophilia mutation factor V Leiden (FVL) associated with an increased total sperm count?SUMMARY ANSWERCarriers of FVL have a higher total sperm count than non-FVL-carriers, which could not be explained by genetic linkage or by observations in a FVL-mouse model.WHAT IS KNOWN ALREADYFVL has a high prevalence in Caucasians despite detrimental health effects. Carriers have been shown to have higher fecundity, which might partly explain this evolutionary paradox.STUDY DESIGN, SIZE, DURATIONWe determined FVL status in two cohorts (Dutch,n = 627; Danish,n = 854) of consecutively included men without known causes for spermatogenic failure, and performed an individual patient data meta-analysis of these two cohorts together with one previously published (Dutch,n = 908) cohort. We explored possible biological underpinnings for the relation between sperm count and FVL, by use of a FVL-mouse model and investigations of genetic linkage.PARTICIPANTS/MATERIALS, SETTING, METHODSParticipants were male partners of subfertile couples (two Dutch cohorts) and young men from the general population (Danish cohort): FVL carrier rate was 4.0%, 4.6% and 7.3%, respectively. There were differences in smoking, abstinence time and age between the cohorts. We corrected for these in the primary analysis, which consisted of a mixed linear effects model, also incorporating unobjectified population differences. In public haplotype data from subjects of European descent, we expl...
Source: Human Reproduction - Category: Reproduction Medicine Source Type: research