Reproductive parameters of community-dwelling men from two regions in flanders are associated with the consumption of self-grown vegetables

Although regional differences in semen parameters have been described, little is known about the etiological factors underlying these variations in male fertility status. We previously reported people from a rural area (Peer) in Flanders to have lower sperm parameters and free testosterone than men from the city of Antwerp. In the present study, our objectives were to investigate to what extent these differences were associated with lifestyle or environmental factors. People in Peer were slightly older, and had a higher body mass index, factors known to affect testosterone concentrations, but not sperm parameters. People consuming locally produced vegetables (n=37 out of 94) but not fruit, had significantly lower serum free testosterone, and luteinizing hormone (LH) (both p=0.04) and non-significantly lower follicle stimulating hormone (FSH) (p=0.05). Per unit increase of monthly intake of locally produced vegetables, free testosterone declined by 0.7% (p=0.01) and sperm concentration by 2.3% (p=0.04) over the whole range of the explanatory variable, while LH declined by 3.6% (p=0.02), FSH declined by 3.5% (p=0.08) and sperm morphology by 7% (p=0.002) in the range 0-10 consumptions per month. No relationship was found with lifelong exposure to cadmium. These results support a hypothesis of impaired gonadotropic signaling causing the regional difference in reproductive parameters. The surprising strong impact of self-grown vegetable consumption did not seem to be related to soil contamination by cadmium. We could not exclude pesticide exposure by inappropriate application, or other factors such as nutritional deficiency, physical activity or stress as contributors to the observed regional differences.