Andrology: Seminal volume and total sperm number trends in men attending subfertllity clinics in the Greater Athens area during the period 1977-1993

The trends for such Important parameters of male fertility asseminal volume and total sperm number were assessed in men livingpermanently in the Greater Athens area over a prolonged periodof time. To this end, the records of three andrological laboratoriesemploying the same method for semen evaluation were analysedretrospectively. Out of 23 850 men examined from 1977 to 1993(17 years) for couple subfertillty, a total of 2385 (10%) wereselected for evaluation by a randomization procedure. Analysisof the data included (i) estimation of mean seminal volume andtotal sperm number per year, (ii) assessment of percentage frequencydistribution for each seminal parameter and (iii) evaluationof seminal volume and total sperm number changes in relationto the year of observation and age of the subjects. A significantdecrease (P < 0.01) of total sperm number was observed overthe years with a mean (± SEM) of 154.3 ± 19.2x 10⁶ at the beginning (1977), dropping to 130.1 ± 13.3x 10⁶ in the final year (1993). Mean seminal volume was lowerin the final year of observation, but its difference from theinitial year value was not significant Frequency distributionanalysis showed a marked decline in the 240–400 x 10⁶sub-set of the range of sperm number values from 16.9 ±4.5% (1977) to 10.6 ± 1.6% in the final year (P <0.01). Multiple regression analysis of seminal volume, totalsperm number, age and year of assessment revealed a significantdecline of the two seminal parameters along the years of observation(P < 0.05 and P < 0.0001 respectively). Over the sameperiod, a marked deterioration of some air pollution indiceswas observed in that area. It is concluded that in this raciallyand ethnically homogeneous sample of men, living under the sameenvironmental conditions, a significant decline in seminal volumeand total sperm number occurred over the 17 years of observation.