[Show abstract][Hide abstract] ABSTRACT: The World Health Organization (WHO) provides guidelines for assessing the various semen variables. A set of reference ranges is given in the WHO Laboratory Manual for the Examination of Human Semen and Sperm-Cervical Mucus Interaction, but several studies indicate that the values should be revised. Furthermore, semen parameters obtained at different laboratories are not directly comparable even if the same methods are used. Thus, it is recommended that each laboratory establish its own reference ranges. In this study, semen from 99 men who had recently achieved a pregnancy were analyzed to establish reference ranges for semen variables. The reference values were based on the group with time to pregnancy (TTP) 12 cycles or less (92%) and abstinence time from 2 to 7 days. The 5th and 10th percentiles for sperm concentration were 10.6 and 16.9 x 10(6)/mL, respectively, and 33% (5th percentile) and 43% (10th percentile) for spermatozoa with progressive motility. These values were below the WHO lower limit. The percentages of ideal spermatozoa (percentage with normal morphology according to WHO strict criteria) were 3 (5th percentile) and 4 (10th percentile). Thirty-nine percent reported that their partners became pregnant during the first cycle after they had stopped using contraception. The semen parameters in this group were compared with the others. Overall, the semen parameters were more favorable in the group with TTP = 1 cycle than in the group with TTP > 1. Sperm concentration, progressive motility, and percentage of ideal spermatozoa according to WHO strict criteria were significantly different in the 2 groups. However, when analyzed by multiple logistic regression, only "total numbers of sperm with progressive motility" remained in the model (P = .002). This is in accordance with previous studies indicating that a combination of semen characteristics provides a better predictor of male fertility potential than the single parameters. In conclusion, new reference ranges for semen variables deviating from the WHO values are established for our laboratory.
Journal of Andrology 01/2006; 27(1):66-71. · 3.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Between 1996 and 1999, the authors invited all young men from five European countries who were undergoing compulsory medical examination for possible military service to participate in a study on male reproductive health. The participation rate was 19% in two cities in Denmark (n = 889), 17% in Oslo, Norway (n = 221), 13% in Turku, Finland (n = 313), 14% in Kaunas, Lithuania (n = 157), and 19% in Tartu, Estonia (n = 190). Each man provided a semen sample, was examined by a physician, and, in collaboration with his mother, completed a questionnaire about general and reproductive health, current smoking habits, and exposure to smoking in utero. After adjustment for confounding factors, men exposed to smoking in utero had a reduction in sperm concentration of 20.1% (95% confidence interval (CI): 6.8, 33.5) and a reduction in total sperm count of 24.5% (95% CI: 9.5, 39.5) in comparison with unexposed men. Percentages of motile and morphologically normal sperm cells were 1.85 (95% CI: 0.46, 3.23) and 0.64 (95% CI: -0.02, 1.30) percentage points lower, respectively, among men exposed in utero, and exposed men had a 1.15-ml (95% CI: 0.66, 1.64) smaller testis size. The associations were present when data from the study centers were analyzed separately (though not in Lithuania, where only 1% of mothers smoked during pregnancy), although the strength of the association varied. Maternal smoking may have long-term implications for the reproductive health of the offspring. This is another good reason to advise pregnant women to avoid smoking.
American Journal of Epidemiology 02/2004; 159(1):49-58. · 4.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Denmark and Norway have a three-fold higher incidence of testicular cancer than Estonia and Finland. Groups of young men from Denmark, Norway, Finland and Estonia were investigated to elucidate whether semen parameters and other related parameters follow a gradient between these countries, as does the gradient in incidence of testicular cancer.
In total, 968 young men from the general population in these four countries were investigated according to the same protocol. Possible confounders were evaluated, and included in the statistical analysis when appropriate. Inter-laboratory differences in assessment of sperm concentrations were controlled by an external quality control programme and morphology assessment was centralized to one person.
The Finnish and Estonian men had an adjusted median sperm concentration of 54 and 57 x 10(6)/ml, respectively and the Norwegian and Danish men 41 x 10(6)/ml. The corresponding total sperm counts were 185, 174, 133 and 144 x 10(6). The frequency of normal sperm in men from Finland was 8.9%, Estonia 9.2%, Norway 6.9% and Denmark 6.4%. Within all four groups of men, a relationship between increasing levels of inhibin-B and increasing sperm counts was observed. However, inhibin-B levels were not predictive of sperm count differences between countries.
It is believed that the men examined were representative of the normal population of young men in all four countries as they were recruited from groups attending a compulsory medical examination, and not selected for known fertility or semen quality. Moreover, the majority of participants had no prior knowledge of their fertility potential. It appears that an east-west gradient exists in the Nordic-Baltic area with regard to semen parameters, this being in parallel with the incidences of testicular cancer. Further investigations are required to determine whether these findings are due to genetic differences, to different environments, or perhaps to a combination of both factors.
Human Reproduction 09/2002; 17(8):2199-208. · 4.67 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Inter-observer variation in andrological examination by 10 clinical investigators from five Nordic and Baltic countries was investigated. In addition, information on intra-observer variation was obtained for six of the 10 investigators. Testicular size was measured using Prader's orchidometer and one of the investigators also performed an ultrasound estimate of testicular size. A highly significant difference (p < 0.001) between observers was found with an inter-observer error of 16% in estimating testicular size in 23 young men. The difference in the estimate tended to increase with increasing testicular size. There was no significant intra-observer difference in two measurements performed on consecutive days. Only differences in median testis size, which were greater than 31% between measurements by two investigators, were found to be significant at the 5% level. The ultrasound estimate of testicular size was significantly lower than the orchidometer estimate, with a mean difference of 3.6 mL for the left testis and 4.3 mL for the right testis. Tanner staging of genitalia and diagnosis of a varicocele was subject to great inter-observer variation, and for the diagnosis of varicocele only one-third of the investigators was able to reproduce their results on a second examination. In conclusion, it was found that the clinical andrological examination of young men is subject to great inter-observer variation. This should be kept in mind when results from different studies are compared as well as in daily clinical practice.
International Journal of Andrology 09/2000; 23(4):248-53. · 3.37 Impact Factor