Research report
Reconsidering the effects of blue-light installation for prevention of railway suicides

https://doi.org/10.1016/j.jad.2013.09.006Get rights and content

Abstract

Background

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.

Methods

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.

Results

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.

Limitations

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.

Conclusions

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.

Introduction

Matsubayashi et al. (2013), in a recent preliminary communication, evaluated the calming effect of blue lights installed at the ends of station platforms by a Japanese railway company as a measure to prevent people from jumping into the path of an oncoming train. They suggested that the installation of blue lights reduced suicides by 84% and issued a press release, reporting only the point estimate (84%) without its confidence interval (95% CI: 14–97%), which was covered by Japan's major news media.

To interpret this finding and translate it into practice, it is important to take a descriptive epidemiological viewpoint, accounting for time, place, and person. Blue lights, if effective in suicide prevention, would work only when illuminated at night. Moreover, the lights, as potentially installed at the ends of railway platforms, would work only in their immediate vicinity—i.e., they would not discourage jumping onto the track from the middle of the platform. Therefore, the finding mentioned above could be misleading unless the times and places of the suicides are taken into account. The aim of this rapid communication is to examine railway suicide attempts in terms of time and place to further evaluate the use of blue lights on platforms for suicide prevention.

Section snippets

Methods

We used data on railway suicide attempts for fiscal years 2002–2011 (from April 2002 to March 2012) compiled by the Japanese Ministry of Land, Infrastructure, Transport and Tourism (MLIT), which were made public pursuant to the Information Disclosure Act. Railway companies are obligated by the Railway Business Act to report all accidents to the MLIT, including suicide attempts, using a uniform format.

We extracted all cases categorized as “suicide attempt” from the data sets. The entries include

Results

Table 1 shows the 5841 reported suicide attempts from April 2002 to March 2012 by time and location. Of these, 43% occurred within station premises, 43% were at night, and 14% fell into both categories. The proportion of nighttime suicide attempts between stations (52%) was greater than that within station premises (32%).

Table 2 shows the 2535 suicide attempts that occurred within station premises. Conservatively assuming that the “unidentified” attempts all occurred at platform ends, a maximum

Discussion

We find that more than half of railway suicide attempts occurred during the day, with many occurring away from station premises. Nighttime suicide attempts within station premises account for only 14% of all railway suicide attempts. Those who entered the track from the platform did not necessarily do so from one of the ends, where the blue lights would potentially have been installed. According to our most conservative estimate, only 28% of suicide attempts within station premises occurred at

Role of funding source

None received.

Conflict of interest

All authors declare that they have no conflicts of interest.

Acknowledgements

We thank Mr Yuichi Sato for providing the data.

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