Reproductive hazards in an industrial setting : an epidemiological assessment

Abstract: Background: As more women of childbearing age engage in the workforceand a lot of new chemicals are available, a growing interest of diagnosing andpreventing reproductive disorders due to occupational and environmentalexposure has occurred. The source location of this thesis is the Rönnskärcopper smelter which is situated in the north of Sweden, in the municipality of Skellefteå. Emissions from the smelter, which have diminished during theperiod 1975-1990 include sulphur dioxide and heavy metals, especially lead,arsenic, cadmium, copper, mercury and zinc. Reproductive studies from the1970s in and around the smelter reported increased risks of spontaneousabortions, malformations and lower birth weight. The aim of this thesis wasto perform a broad and long-term epidemiological assessment of adversereproductive outcome in and around the smelter and to determine if theexposed population suffered from reproductive disturbances during the recentdecades.Subjects and methods: The study involve two main sources of data. Onewas a retrospective cohort formed through record linkage of populationregisters, the medical birth register (1961-90), the register of congenitalmalformations (1973-90) and the cancer register (1961-90). As another source,information on reproductive history, life-style and work related factors wasobtained from a questionnaire study in 1992. An exposed population wasdefined as smelter workers and their children, and also neighbours to thesmelter and their children.Results: In the register study, compared to the reference population, nooverall significant increased risk of malformations, childhood cancer, low birthweight or perinatal death was found in the exposed group. In thequestionnaire study, regarding infertility, no environmental effects were found.Also, no increased risk of a prolonged waiting time to pregnancy or increasedrisk of spontaneous abortions were associated with occupational or environmentalfactors.Conclusion: With the lack of a high statistical power in mind, due to smallsample sizes in some of the studies, the summary of our findings includingseveral outcomes, different epidemiological study designs and studies coveringa long period of time gives no evidence for any increased risk of reproductivehazards due to occupational or environmental exposure.