| Summary: | The present dissertation focuses on the reproductive health effects in humans from four diverse populations, including an Inuit population from Greenland, a Swedish population of fishermen and fishermen's wives, and urban populations from the cities of Warsaw in Poland and Kharkiv in Ukraine, representing populations with considerable variations in organochlorine exposure levels due to differences in the consumption of contaminated food items and the period since banning the use of the organochlorines selected in the present study. Due to bioaccumulation and their long half-lives in humans, these compounds are still ubiquitously detected in humans. The study included a total of 2,269 women who provided information via detailed questionnaires and 798 men who provided semen samples. Time to pregnancy varied between the populations included, whereas semen quality was remarkably similar with only minor differences in motility between countries and within regions in Greenland. An extensive quality control programme ensured a low level of variation between analysers in the evaluation of semen quality during semen sample collection. Sperm concentration and morphology were not associated with PCB-153 or DDE exposure, but sperm motility was consistently associated with PCB-153 exposure across populations. Xeno-estrogen, -androgen and dioxin-like activity in serum samples were not consistently associated with semen quality measures, indicating that the associations observed with sperm motility were not caused via direct effects on these receptors. The sperm chromatin structure assay showed a higher level of DNA fragmentation under higher PCB-153 exposure levels in the European populations, but not in the Greenlandic population. Disturbances in the female menstrual cycle were not consistently associated with PCB-153 or DDE exposure across the countries, but our results suggested a higher probability of ever having a spontaneous abortion among women with high PCB-153 or DDE exposure levels. Overall, the results suggest that PCB-153, but probably not DDE, may affect aspects of male and female reproductive functioning in European and Arctic populations at the levels of exposure currently experienced in these populations, although the associations observed did not seem to be a major cause of reduced human fertility.
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