Technical Report No. 13-89
Congenital malformations, stillbirths, and early mortality among the children of atomic bomb survivors: A reanalysis
Otake M, Schull WJ, Neel JVEditor’s note: A publication based on this report was published in Radiat Res 122:1-11, 1990.
Summary
Of all data sets pertinent to estimating the genetic risks to humans after exposure to ionizing radiation, potentially the most informative is that comprised of the cohort of children born to A-bomb survivors. We present here an analysis of the relationship between parental exposure history and “untoward pregnancy outcomes” (UPO) within this cohort, using to the fullest extent possible the recently revised estimates of the doses received by the parents-the so-called DS86 doses. Available for study are 70,073 pregnancy terminations, but DS86 doses have not been or presently cannot be computed on 14,770 of these. The frequency of UPOs, defined as a pregnancy terminating in a child with a major congenital malformation, and/or stillborn, and/or dying in the first 14 days of life, increases with combined (summed) parental dose, albeit not significantly so.
Under a standard linear model, when the sample of observations is restricted to those children whose parents have been assigned the newly established DS86 doses (n = 55,303), ignoring concomitant sources of variation and assuming a neutron RBE of 20, the estimated increase per sievert in the predicted frequency of untoward outcomes is 0.00354 (plus or minus 0.00343). After adjustment for concomitant sources of variation, the estimated increase per sievert in the proportion of such births is 0.00422 (plus or minus 0.00342) if the neutron RBE is assumed to be 20. A one-hit model with adjustment for concomitants results in an almost identical value, viz., 0.00412 (plus or minus 0.00364).
When the sample is extended to include parents lacking the full array of dose parameters necessary to calculate the DS86 dose, but sufficient for an empirical conversion of the previously employed T65DR dose system to its DS86 equivalent, we find under the linear model that the estimated increase per sievert in UPOs is 0.00264 (plus or minus 0.00277) at an RBE of 20, after adjustment for concomitants. (Now n = 69,706; for 367 of the 70,073 outcomes, neither a DS86 nor an ad hoc dose can be calculated.) The corresponding value with the one-hit model is 0.00262 (plus or minus 0.00294). The former value is some 31% higher than that published previously.
Of all data sets pertinent to estimating the genetic risks to humans after exposure to ionizing radiation, potentially the most informative is that comprised of the cohort of children born to A-bomb survivors. We present here an analysis of the relationship between parental exposure history and “untoward pregnancy outcomes” (UPO) within this cohort, using to the fullest extent possible the recently revised estimates of the doses received by the parents-the so-called DS86 doses. Available for study are 70,073 pregnancy terminations, but DS86 doses have not been or presently cannot be computed on 14,770 of these. The frequency of UPOs, defined as a pregnancy terminating in a child with a major congenital malformation, and/or stillborn, and/or dying in the first 14 days of life, increases with combined (summed) parental dose, albeit not significantly so.
Under a standard linear model, when the sample of observations is restricted to those children whose parents have been assigned the newly established DS86 doses (n = 55,303), ignoring concomitant sources of variation and assuming a neutron RBE of 20, the estimated increase per sievert in the predicted frequency of untoward outcomes is 0.00354 (plus or minus 0.00343). After adjustment for concomitant sources of variation, the estimated increase per sievert in the proportion of such births is 0.00422 (plus or minus 0.00342) if the neutron RBE is assumed to be 20. A one-hit model with adjustment for concomitants results in an almost identical value, viz., 0.00412 (plus or minus 0.00364).
When the sample is extended to include parents lacking the full array of dose parameters necessary to calculate the DS86 dose, but sufficient for an empirical conversion of the previously employed T65DR dose system to its DS86 equivalent, we find under the linear model that the estimated increase per sievert in UPOs is 0.00264 (plus or minus 0.00277) at an RBE of 20, after adjustment for concomitants. (Now n = 69,706; for 367 of the 70,073 outcomes, neither a DS86 nor an ad hoc dose can be calculated.) The corresponding value with the one-hit model is 0.00262 (plus or minus 0.00294). The former value is some 31% higher than that published previously.