Fulbright Scholar, Radiation Effects Research Foundation, Hiroshima, Japan.
Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Epidemiol Psychiatr Sci. 2021 Jun 4;30:e43. doi: 10.1017/S204579602100024X.
The long-term physical health effects of the atomic bombings of Hiroshima and Nagasaki are well characterised, but the psychological effects remain unclear. Therefore, we sought to determine whether measures of exposure severity, as indirect measures of psychological trauma arising from exposure to the atomic bombings, are associated with suicide mortality among atomic bomb survivors.
The Life Span Study is a prospective cohort study of 93 741 Japanese atomic bomb survivors who were located within 10 km of the hypocentre in Hiroshima or Nagasaki at the time of the bombings in 1945, and 26 579 residents of Hiroshima and Nagasaki who were not in either city at the time of the bombings, matched to survivors on city, sex and age. Measures of exposure severity included: proximity to the hypocentre, type of shielding between the survivor and the blast and self-reported occurrence of acute radiation and thermal injuries. Date of death was obtained from the Japanese National Family Registry system. Cause of death was obtained from death certificates. Adjusted hazard ratios (HRs) were estimated from Cox regression models overall and stratified by sex and age.
During the 60-year follow-up period (1950-2009), 1150 suicide deaths were recorded among 120 231 participants (23.6 per 100 000 person-years): 510 among 70 092 women (17.2 per 100 000 person-years) and 640 among 50 139 men (33.6 per 100 000 person-years). Overall, there was no association of proximity, type of shielding or the occurrence of acute injuries with suicide mortality. Among those <25 years of age at the time of the bombings, increased suicide risk was observed for survivors outside v. shielded inside any structure (HR: 1.24; 95% confidence interval (CI): 1.03, 1.48; interaction p = 0.054) and for those who reported flash burns (HR: 1.32; 95% CI: 1.00, 1.73; interaction p = 0.025). Sex-stratified analyses indicated that these associations were limited to men. Among women, closer proximity to the hypocentre was associated with a non-significant increase in suicide risk, with a positive association between proximity and suicide risk observed among women <15 years of age (HR: 1.09 per km; 95% CI: 1.00, 1.18; interaction p = 0.067).
Proximity to the hypocentre, shielding and acute injury presence do not generally appear to influence suicide mortality among atomic bomb survivors. However, heterogeneity may exist by age and sex, with younger survivors potentially more sensitive to psychological trauma. Coupled with other studies, our results suggest the importance of long-term monitoring of mental health among young populations exposed to catastrophic events or mass trauma.
广岛和长崎原子弹爆炸的长期身体健康影响已得到充分描述，但心理影响仍不清楚。因此，我们试图确定暴露严重程度的措施，作为因暴露于原子弹爆炸而产生的心理创伤的间接指标，是否与原子弹幸存者的自杀死亡率相关。
寿命研究是一项针对 93741 名日本原子弹幸存者的前瞻性队列研究，这些幸存者在 1945 年原子弹爆炸时位于广岛或长崎震中 10 公里范围内，以及 26579 名在原子弹爆炸时不在这两个城市的广岛和长崎居民，与幸存者在城市、性别和年龄方面相匹配。暴露严重程度的措施包括：与震中之间的距离、幸存者与爆炸之间的屏蔽类型以及自我报告的急性辐射和热损伤的发生。死亡日期从日本国家家庭登记系统中获得。死因从死亡证明中获得。总体和按性别和年龄分层的 Cox 回归模型估计了调整后的风险比（HR）。
在 60 年的随访期间（1950-2009 年），在 120231 名参与者中记录了 1150 例自杀死亡：70092 名女性中有 510 例（每 100000 人年 17.2 例），50139 名男性中有 640 例（每 100000 人年 33.6 例）。总体而言，接近程度、屏蔽类型或急性损伤的发生与自杀死亡率无关。在原子弹爆炸时年龄<25 岁的幸存者中，与任何建筑物内有屏蔽的幸存者相比，在建筑物外的幸存者自杀风险增加（HR：1.24；95%置信区间（CI）：1.03，1.48；交互 p = 0.054），且报告有闪光烧伤的幸存者自杀风险增加（HR：1.32；95%CI：1.00，1.73；交互 p = 0.025）。性别分层分析表明，这些关联仅限于男性。在女性中，更接近震中与自杀风险的增加无关，但在<15 岁的女性中，接近震中与自杀风险之间存在正相关（HR：每公里 1.09；95%CI：1.00，1.18；交互 p = 0.067）。
一般来说，与震中之间的距离、屏蔽和急性损伤的存在似乎不会影响原子弹幸存者的自杀死亡率。然而，年龄和性别可能存在异质性，年轻幸存者可能更容易受到心理创伤的影响。结合其他研究，我们的结果表明，在经历灾难性事件或大规模创伤的年轻人群中，对心理健康进行长期监测的重要性。
