Radiation risks in perspective: radiation-induced cancer among cancer risks

The majority of the public in industrial countries believes that pollution and low doses of radiation are threats to good health. As a matter of fact, when these putative risks are compared to those originating from lifestyle, they appear very small. In particular, the risks associated with low doses of irradiation, even when they are assessed with the most pessimistic models, appear extremely small. Public anxiety is fuelled by the uncertainty regarding the magnitude of this risk and the use of the linear no threshold (LNT) hypothesis, which gives credence to the concept that even the smallest doses are harmful. There are a number of scientific and epidemiological data currently under debate that are not consistent with the LNT hypothesis. For example, no difference in the incidence of cancers or of birth defects has been observed between regions with low or high natural irradiation. This inconsistency between perceptions and data underlines the role of psychological factors studied since 1957 which should be placed in the perspective of the public’s present attitude toward risk and technology. Social amplification or attenuation of risk may occur in several ways. Fearful concern about radiation began in 1955, with the beginning of the Cold War, when the possibility of a nuclear holocaust appeared very real. Analysis of the data shows that these fears of technology could have a detrimental effect; they should therefore be investigated and understood. Received: 13 October 1999 / Accepted in revised form: 27 December 1999     

Assessment of reproductive risks

In the regulatory process, the hazards posed by potentially toxic agents to the female and male reproductive systems and to developing young are evaluated by risk assessment procedures. In this paper, toxicity testing and the regulatory process are discussed, with emphasis on risk assessment. The suggested testing protocols of the Pesticide Assessment Guidelines (U.S. EPA) are presented as an example of testing that might be done to produce toxicity data for an agent. Protocols and end points that are utilized in testing for reproductive effects are described. Included are acute, subchronic, chronic, and short-term tests. The four components of reproductive risk assessment (hazard identification, dose-response assessment, exposure assessment, and risk characterization) are examined. Effects of dibromochloropropane on rabbit testicular parameters are used to demonstrate approaches that could be taken in doing a reproductive risk assessment. Research needs for screening methods, adequate dose-response testing, toxicokinetics, end point development, and extrapolation methods are identified. Finally, this paper discusses selected areas in which changes in reproductive risk assessment are anticipated, as well as the mechanism for influencing the nature and extent of those changes.     

Morbid obesity: Pregnancy risks, birth risks and status of the newborn

In perinatal medicine, severe obesity of the mother occurs in approximately 1% of cases. This is a problem of increasing importance because of the rising prevalence of juvenile obesity. Our retrospective cohort study aimed at characterising high-risk pregnancies associated with morbid obesity (body mass index [BMI]≥40). This is of interest not only from an epidemiological perspective and for developing guidelines for clinical care but also from an anthropological point of view.We analysed the German perinatal statistics of the years 1998-2000 with data from more than 500,000 pregnancies. Pregnant women with coexistent morbid obesity were compared to a normal weight reference sample with regard to gestational, perinatal and neonatal risks. Birth weight percentiles were used to classify the neonates according to size (hypotrophy if <10th, hypertrophy/foetal macrosomia if >90th).The obtained risk profile for morbidly obese pregnant women primarily showed pregnancy related diseases, such as hypertension, pre-eclampsia and gestational diabetes. Hypertension and signs of foetal hypoxaemia occurred at higher frequencies with morbid obesity.Hypertrophic neonates were born 3.3 times more often to obese mothers than to mothers of the normal weight. At a BMI≥40 the rates of complications such as pre-eclampsia, gestational diabetes, impending foetal hypoxaemia, foetal macrosomia, as well as neonatal infections and hyperbilirubinaemia were significantly higher. Obesity and maternal comorbidities, accounted for a higher rate of caesarean sections of up to 38.4% at a BMI≥45. All differences were highly significant.Preconceptionally, the therapeutic approach should be weight reduction.