Radiation-Related Ophthalmological Changes and Aging among Hiroshima and Nagasaki A-Bomb Survivors: A Reanalysis

Abstract

The relationship of ionizing radiation to the age-related ophthalmological findings of the 1978-1980 ophthalmological examination of A-bomb survivors of Hiroshima and Nagasaki has been reanalyzed using DS86 eye organ dose estimates. The main purpose of this reevaluation was to determine whether age and radiation exposure, as measured using the recently revised dosimetry information (DS86), have an additive, synergistic, or antagonistic effect. The data in this study are limited to axial opacities and posterior subcapsular changes, for which a definite radiation-induced effect has been observed in Hiroshima and Nagasaki A-bomb survivors. The best model fitting for axial opacities gives a significant positive effect for both linear dose and linear age-related regression coefficients and a significant negative effect for an interaction between radiation dose and age. Such a negative interaction implies an antagonistic effect in that the relative risks in relation to radiation exposure doses become smaller with an increase in age. On the other hand, the best-fitting relationship for posterior subcapsular changes suggested a linear-quadratic dose and linear age-related effect. The estimate of the quadratic dose coefficient shows a highly negative correlation with age, but the negative quadratic dose term is extremely small and is of little biological significance.

Dosimetry for a Study of Low-Dose Radiation Cataracts among Chernobyl Clean-up Workers

“…Several different studies reported that exposure at an early age confers more risk per unit dose than exposure at a later age (26,30,32,41), although other human data have not provided support for this (33). Most data sets, however, have had only a limited age range, so arriving at a broad-based answer is difficult.…”

Lens opacities among physicians occupationally exposed to ionizing radiation – a pilot study in Finland

“…All the opacities detected at ophthalmological examinations were minor. Nuclear opacities were the most common finding [8 (14%) subjects (95% CI 6-26), including nuclear colour changes observed in 6 (11%) subjects (95% CI [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Cortical opacities (grade 1-2 changes) were found in 4 (7%) cases (95% CI 2-17%), with 9 (17%) additional subjects (95% CI 7-28) showing cortical traces.…”

“…Re-analyses of atomic bomb survivor data have demonstrated that the findings are compatible both with threshold (about 1.5 Sv) and linear models (10)(11)(12)(13). In one study, children whose lens was exposed to 1 Gy during radiotherapy had a 50% increased risk of developing a posterior subcapsular opacity and a 35% higher risk for cortical lens opacities, compared with unexposed controls (16).…”

“…Hereditary factors play a role and medical risk factors include diabetes as well as corticosteroid, diuretic, and beta blocker use (4)(5)(6)(7)(8)(9). Cataracts may occur more commonly among women (10).…”

“…Cataractogenesis associated with ionizing radiation is well known from experimental studies and has been demonstrated in humans by studies among survivors of the Hiroshima and Nagasaki atomic bombs (10)(11)(12)(13). Cataract is a frequent complication of radiotherapy for intraocular melanoma (14)(15).…”