Table 1.
Number of subjects and person-years
| Mother’s weighted absorbed uterine dose (Gy) | Person-years | ||||||
|---|---|---|---|---|---|---|---|
| Not in city | < 0.005 | < 0.1 | < 1 | ≥ 1 | Total | ||
| Mean dose (Gy) | 0.001 | 0.037 | 0.327 | 1.635 | 0.123 | ||
| N (%) | N (%) | N (%) | N (%) | N (%) | N (%) | ||
| Sex | |||||||
| Male | 284 (48.5) | 479 (49.4) | 214 (49.5) | 213 (49.4) | 24 (53.3) | 1214 (49.3) | 67,437 |
| Female | 301 (51.5) | 491 (50.6) | 218 (50.5) | 218 (50.6) | 21 (46.7) | 1249 (50.7) | 70,567 |
| City | |||||||
| Hiroshima | 508 (86.8) | 759 (78.2) | 383 (88.7) | 364 (84.5) | 31 (68.9) | 2045 (83.0) | 115,058 |
| Nagasaki | 77 (13.2) | 211 (21.8) | 49 (11.3) | 67 (15.5) | 14 (31.1) | 418 (17.0) | 22,945 |
| Cohort sources | |||||||
| 1960 Census | 22 (3.8) | 171 (17.6) | 42 (9.7) | 54 (12.5) | 6 (13.3) | 295 (12.0) | 14,905 |
| Birth report | 212 (36.2) | 393 (40.5) | 280 (64.8) | 298 (69.1) | 35 (77.8) | 1218 (49.5) | 72,207 |
| Master file | 351 (60.0) | 406 (41.9) | 110 (25.5) | 79 (18.3) | 4 (8.9) | 950 (38.6) | 50,891 |
| Trimester | |||||||
| 1st trimester | 164 (28.0) | 340 (35.1) | 139 (32.2) | 126 (29.2) | 13 (28.9) | 782 (31.7) | 43,381 |
| 2nd trimester | 222 (37.9) | 351 (36.2) | 162 (37.5) | 175 (40.6) | 20 (44.4) | 930 (37.8) | 52,333 |
| 3rd trimester | 199 (34.0) | 280 (28.9) | 131 (30.3) | 130 (30.2) | 12 (26.7) | 751 (30.5) | 42,289 |
| Birth weight | |||||||
| Normal (≥ 2500 g) | 516 (88.2) | 716 (73.8) | 357 (82.6) | 343 (79.6) | 23 (51.1) | 1955 (79.4) | 110,549 |
| Low (< 2500 g) | 45 (7.7) | 59 (6.1) | 38 (8.8) | 47 (10.9) | 17 (37.8) | 206 (8.4) | 11,380 |
| Unknowna | 19 (3.2) | 33 (3.4) | 17 (3.9) | 31 (7.2) | 5 (11.1) | 105 (4.3) | 5747 |
| No informationb | 5 (0.9) | 162 (16.7) | 20 (4.6) | 10 (2.3) | 0 (0.0) | 197 (8.0) | 10,327 |
| Head sizec | |||||||
| Male, normal head size | 282 (99.3) | 475 (99.2) | 213 (99.5) | 196 (92.0) | 17 (70.8) | 1183 (97.4) | 65,832 |
| Male, small head sized | 2 (0.7) | 4 (0.8) | 1 (0.5) | 17 (8.0) | 7 (29.2) | 31 (2.6) | 1605 |
| Female, normal head size | 295 (98.0) | 486 (99.0) | 212 (97.2) | 208 (95.4) | 18 (85.7) | 1219 (97.6) | 68,959 |
| Female, small head sizee | 6 (2.0) | 5 (1.0) | 6 (2.8) | 10 (4.6) | 3 (14.3) | 30 (1.2) | 1607 |
| Father’s survival status | |||||||
| Alive | 264 (45.1) | 487 (50.2) | 280 (64.8) | 255 (59.2) | 21 (46.7) | 1307 (53.1) | 75,521 |
| Lost | 50 (8.5) | 146 (15.1) | 101 (23.4) | 146 (33.9) | 24 (53.3) | 467 (19.0) | 26,632 |
| Mother’s survival status | |||||||
| Alive | 288 (49.2) | 578 (59.6) | 347 (80.3) | 360 (83.5) | 40 (88.9) | 1613 (65.5) | 93,249 |
| Lost | 26 (4.4) | 55 (5.7) | 34 (7.9) | 41 (9.5) | 5 (11.1) | 161 (6.5) | 8904 |
| Parent’s survival status | |||||||
| No information | 271 (46.3) | 337 (34.7) | 51 (11.8) | 30 (7.0) | 0 (0.0) | 689 (28.0) | 35,850 |
| Total | 585 (100) | 970 (100) | 432 (100) | 431 (100) | 45 (100) | 2463 (100) | 138,003 |
aUnknown: Individuals who were surveyed but of whom information was insufficient in either the clinical program and the socioeconomic survey
bNo information: Individuals who were not surveyed in any programs
cSixty-two subjects with small heads were identified from the clinical program internal documents. Individuals other than 62 subjects with small heads, three individuals with small head size who died before the measurement, and those derived only from the mortality program were treated as individuals with normal head size
dAmong 31 male subjects with small head size, 16 individuals were exposed in the 1st trimester, 9 individuals in the 2nd trimester, and 6 individuals in the 3rd trimester
eAmong 30 female subjects with small head size, 18 individuals were exposed in the 1st trimester, 10 individuals in the 2nd trimester, and 2 individuals in the 3rd trimester