Überlebenszeit und Todesursachen fertiler und subfertiler Männer

The intention of this study was the investigation of a potential association between the overall and cause-specific mortality on the one hand and male fertility on the other. The database were medical records of men with normal and low sperm counts, measured in the outpatient facility of the Department of Andrology at Marburg University. All medical records of men born before January 1, 1942 were included. The vitality status of the included cases at December 31, 2006 was detected via registration offices. For the analyses, all cases with azoospermia were excluded. In county public health agencies, copies of the death certificates of the deceased cases were asked. The causes-of-death were coded to the ICD-10. The cases were classified into different fertility groups according to their sperm concentration. According to reference limits published by the WHO 2010, men with a sperm concentration of ≥ 15×106/ml are classified as fertile (normozoospermic) and men with a sperm concentration of < 15×106/ml are classified as subfertile (oligozoospermic). In addition to the comparison of fertile and subfertile cases, a comparison of cases and fecund controls was accomplished. To this end, men were chosen who had a similar age as the cases and who fathered a child around the examination date of the cases. Under application of the Kaplan-Meier-Estimator, the survival functions of the fertility groups were displayed. For this, the actual life span of the deceased cases and the estimated life span of the cases that were still alive were consulted. Via Log-Rank-, Breslow- and Tarone Ware-test, the survival functions were tested for statistical differences. Upon the examination of all cases, no differences between fertile and subfertile cases could be found. In cases where the sample was separated by the median of the birthdate (October 6, 1935), a difference in the mortality between fertile and subfertile cases of the early cohort could be detected. For the late cohort no such effect could be discovered. Semi-parametric and parametric methods (Cox-Regression an accordingly Gompertz-Makeham- and AFT-models) were able to detect disparities in the mortality between the fertility groups of the early cohort. Subfertile men, thus, showed a mortality risk that was 1.5 times higher than the mortality risk of fertile men. Beside the fertility status, a total fertility index was extracted using factor analysis (Principal component extraction), in which die variables total fertility index, total number of sperms, sperm motility, and sperm morphology were included in the analyses. Using the same semi-parametric and parametric methods, which had been used for the investigation of the fertility status, an interrelation ship between the total fertility and the survival time with in the total control sample could be found. The mortality risk decreased with a increasing total fertility index. The semi-parametric and parametric methods have been applied besides the above-mentioned investigations for the total life span also for the observation of the life time beginning with the start point of investigation. This resulted in comparable findings. Using bi-variate and multi-variate methods, no differences between the fertility groups with respect to the three most frequent causes-of-death (cancer, cardiovascular diseases and diseases of the pulmonary system) could be stated. A comparison of cases and controls did not result in mortality differences between the two groups. The subsumption of the actual results into the state of the respective research is hampered by the fact that apparently only two studies in internationally accessable journals have focused on the examination of potential correlation between the mortality of men and their fertility. These are the dissertation of Groos (2006), the set of data of which is the basis of the present study as well as the comprehensive register study by Jensen et al. (2009). The few known publications, however, arrive at similar results. Explanations for the differences in the survival time of fertile and sub-fertile men may be found in influencing social factors. Childlessness has negative influences on the health attitude and the morbidity. Furthermore, biological aspects such as genetic dispositions and influences in early childhood or already in utero could contribute to an explanation. The present study evaluated a correlation between fertility dysfunctions, expressed by subnormal sperm parameters, and the mortality of infertility patients. This evidence as well as the results of other study allow an assumption with respect to a marker function of the reproductive courses of events of men for the general health status. For more precise examinations of these correlations, in extended examinations, information on the morbidity and on aspects of the vitae of the infertility patients should be included.