Adverse Reproductive Outcomes in Families of Atomic Veterans The Feasibility of Epidemiologic Studies (1995) / Chapter Skim
Currently Skimming:
7. ADVERSE REPRODUCTIVE OUTCOMES
7. ADVERSE REPRODUCTIVE OUTCOMES
Pages 42-61
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 42... ...
This diversity of possible origins makes difficult the assignment of causation in any specific instance. Of primary interest here are those adverse reproductive outcomes that may have arisen through the induction of a deleterious mutation in the paternal germ cells as a consequence of exposure to ionizing radiation.
|
From page 43... ...
Current research on adverse reproductive outcomes has been expanded to include effects on the reproductive systems of both men and women as well as effects on the offspring. This expanded list of effects is shown in Table 4 and includes menstrual cycle changes; semen characteristics; fecundability and fertility; embryonic and fetal loss; any complication affecting the embryo, fetus, or mother; infant morbidity and mortality; and childhood malignancies.
|
From page 44... ...
The role of paternal exposure in the origin of many adverse reproductive and developmental outcomes has not been investigated extensively in humans (Olshan and Faustman, 1993~. The effects of chemicals or ionizing radiation on the sperm, chromosome, and fertility have been demonstrated (Wyrobek et al., 1983; Martin et al., 1986; Geneseca et al., 1990~.
|
From page 45... ...
may affect semen quality and result in reduced fertility or sterility when individuals are exposed to high doses. An increased risk of fetal loss (spontaneous abortion)
|
From page 46... ...
The doses and time course of the process in humans have been studied extensively. In general, the human data related to testicular effects are reported from accidental exposures or from males irradiated for therapeutic reasons, for example, as a treatment for testicular cancer.
|
From page 47... ...
Spontaneous abortion rates as high as 80% of all conceptions have been suggested, but the most widely cited rates are 30-35% (Wilcox et al., 19881. Of clinically recognized pregnancies, approximately 15% will spontaneously abort.
|
From page 48... ...
Other known or suspected maternal risk factors for spontaneous abortion are maternal smoking, which primarily increases the risk of abortion of euploid fetuses; maternal alcohol use; occupational exposure to lead, vinyl chloride, and solvents; exposure to antineoplastic drugs; cocaine use; and heavy maternal caffeine use. Maternal infection with malaria, rubella, rubeola, herpes virus, cytomegalovirus, and genital mycoplasmas has been associated with an increased risk of spontaneous abortion.
|
From page 49... ...
A short interval between pregnancies has recently been reported to be a possible risk factor for delivery of a preterm, low birth weight infant and, potentially, as an important explanatory factor for the racial disparity in adverse pregnancy outcomes (Rawlings et al., 19951. Neither paternal nor maternal exposure to low dose radiation is considered to be a risk factor for preterm birth.
|
From page 50... ...
Results from the atomic bomb survivors show that high doses had no effects on PMR (Neel and Schull, 1991) , so no effect would be expected at the much lower doses received by Atomic Veterans.
|
From page 51... ...
However, when the frequency of sex chromosome aneuploidy is examined in the context of the combined parental gonadal dose, there is a small but statistically nonsignificant increase in these anomalies with increasing parental dose (Neel et al., 1990~. Developmental Abnormalities Developmental abnormalities can affect any organ, and as a result, there are several hundred potential diagnostic categories.
|
From page 52... ...
cd o · cd ~ ce o a)
|
From page 53... ...
~ - oo ~ ~ ~ ~ cr~ ~ 0 o o - o o ~o o c~ ~ ~ ~ ~ o ~ ~ o ~ ~ ~ c~ ~c~ ~ ~ ~ - ~ o o o o o -o o ~ ~c~ ~ ~ c~ - )
|
From page 54... ...
These maternal exposures should be excluded in considering the birth defects attributable to paternal exposures. There was no evidence of an increased risk of congenital malformations following paternal exposure to ionizing radiation or in children of atomic bomb survivors (Neel and Schull, 19911.
|
From page 55... ...
Among 500,000 Births All malformations 57.0128,505 All neoplasms 1.16580 Hemangiomas and lymphangioma 2.061,030 Strabismus 0.87435 Heart block fibrillation, tachycardia 0.33165 Inguinal hernia plus obstruction 7.683,840 Anencephaly 0.41205 Spina bifida 1.40700 Hydrocephaly 1.40700 Eye anomalies 0.54270 Common truncus 0.21105 Transposition of great vessels 0.99495 Tetralogy of Fallot 0.70350 Ventricular septal defect 6.073,035 Atrial septal defect 0.50250 Heart valve 1.73865 Other heart anomalies 0.87435 Total heart anomalies 11.075,535 Patent ductus arteriosus 2.191,095 Coarctation of aorta 0.62310 Single umbilical artery 0.78390 Cleft lip palate 1.86930 Pyloric stenosis 8.014,005 Tracheal-esophageal fistula 0.45225 Other digestive system anomalies 1.69845 Undescended testicles 0.62310 Hypospadias 1.40700 Congenital hydrocele 1.57785 Other genital organ anomalies 1.03515 All talipes 3.301,650 Polysyndactyly 2.191,095 Limb reduction 0.66330 Congenital dislocation of hip 0.99495 Lower limb anomalies 0.21105 Skull and face anomalies 0.62310 Other muscular-skeletal anomalies 1.16580 Skin anomalies 2.621,310 Down syndrome 1.36680 Other autosome anomalies 0.58290 Other unspecified multiple anomalies 1.28640 55 " Data are based on malformations found among 24,224 live births in five Connecticut Hospitals over a 24-month period. SOURCE: Modified from Bracken (1983)
|
From page 56... ...
If both parents were exposed? the resulting sex ratio -or proportion of male births would be related to the individual parental doses and the frequency of dominant versus recessive lethal mutations.
|
From page 57... ...
MORTALITY AMONG THE CHILDREN OF EXPOSED PARENTS The largest study by far of the effects of parental exposure to ionizing radiation on mortality among their children conceived subsequent to irradiation is the study of the offspring of the atomic bomb survivors. That study involves the surveillance of approximately 72,000 children born alive between May 1946 and December 1984.
|
From page 58... ...
with increasing parental dose either for all cancers combined or for leukemia, the most common of the childhood cancers, which were considered separately. This was also true when the data were restricted to those individuals whose fathers alone were exposed.
|
From page 59... ...
Moreover, the findings among children at Sellafield were significantly at variance with those among the children of the atomic bomb survivors (Little, 1990, 1991, 19921. A further complication in the acceptance of the findings and hypothesis of Gardner and colleagues has been the finding of similarly raised levels of leukemia around potential nuclear facilities in Britain (Cook-Mozaffari et al., 1989)
|
From page 60... ...
For example, among the survivors exposed in utero to the atomic bombing of Hiroshima and Nagasaki, an individual was considered to be severely mentally retarded if he or she was unable to form coherent sentences, to perform simple arithmetic tasks, or to manage his or her own affairs or was institutionalized. The World Health Organization restricts the term "severe mental retardation" to those individuals with an IQ of less than 50; individuals with IQs in the range of 50 to 70 are described as mildly retarded.
|
From page 61... ...
Clinical studies of the children of the atomic bomb survivors conceived after the exposure did not extend beyond the 10th month following birth and thus provide limited information. The data that are available from the study of atomic bomb survivors fail to demonstrate an increased risk of any form of mental retardation, including an increased risk of Down syndrome.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.