Faculty of Medicine, University of Tsukuba, Tsukuba-shi, Ibaraki 305-8577, Japan.
J Affect Disord. 2014 Jan;152-154:183-5. doi: 10.1016/j.jad.2013.09.006. Epub 2013 Sep 14.
A recent preliminary communication suggested that the calming effect of blue lights installed at the ends of railway platforms in Japan reduced suicides by 84%. This estimate is potentially misleading from an epidemiological point of view and is reconsidered in the present study.
Governmental data listing all railway suicide attempts in Japan from April 2002 to March 2012 were used to investigate the proportion of suicide attempts within station premises, where blue lights are potentially installed, and at night, when they would be lit. For those suicide attempts within station premises, we also estimated the proportion that occurred at the ends of the platforms at night.
Of 5841 total reported suicide attempts, 43% occurred within the station premises, 43% occurred at night (from 18:00 to 05:59), and 14% occurred both within the station premises and at night. Of the 2535 attempts within station premises, 32% occurred at night and 28% at most were at the end of a platform at night.
The exact proportion of nighttime suicide attempts at the ends of railway platforms was not calculable. Nonetheless, the proportion of suicide attempts that is potentially preventable by blue lights should be less than our conservative estimate.
The installation of blue lights on platforms, even were they to have some effect in preventing railway suicides at night, would have a much smaller impact than previously estimated.
最近的初步报告显示，日本在铁路月台末端安装的蓝色灯光具有镇静效果，可将自杀率降低 84%。从流行病学的角度来看，这一估计结果可能具有误导性，本研究对此进行了重新考虑。
本研究使用了日本政府列出的 2002 年 4 月至 2012 年 3 月期间所有铁路自杀未遂的数据，以调查在月台内、蓝色灯光可能安装的地方以及夜间（18:00 至 05:59）发生的自杀未遂的比例。对于那些发生在月台内的自杀未遂事件，我们还估计了夜间发生在月台末端的比例。
在报告的 5841 例总自杀未遂事件中，43%发生在月台内，43%发生在夜间（18:00 至 05:59），14%同时发生在月台内和夜间。在 2535 例发生在月台内的自杀未遂事件中，32%发生在夜间，其中 28%最有可能发生在夜间月台的末端。
无法计算夜间在铁路月台末端发生的自杀未遂事件的确切比例。尽管如此，通过蓝色灯光预防夜间铁路自杀的潜在可预防的自杀未遂事件比例应低于我们的保守估计。
即使在夜间安装蓝色灯光对防止铁路自杀可能有一定效果，其影响也比之前估计的要小得多。
