Background The purpose of this study is to analyse the trends in deaths, hospitalizations and out-patient visits due to external causes in Japan and to explore strategies for injury prevention.

Methods The WHO standard population data and data on mortality caused by external causes made available by the Vital Statistics of Japan were used. Also, the rates of hospitalizations and outpatient visits due to unintentional injuries were calculated using the Patient Survey of Japan.

The deaths caused by the Great East Japan Earthquake in 2011 were removed from the analysis to avoid confounding.

Results Among 0–14 year olds, the mortality due to external causes reduced from 13.2 per 100,000 populations in 1984 to 3.9 in 2011. Rate of hospitalizations reduced from 610 per 100,000 in 1984 to 478 in 2011. Rate of out-patient visits increased from 35,712 per 100,000 in 1984 to 37,118 in 2011.

Among 15–44 year olds, the mortality due to external causes reduced from 36.7 to 30.5. Rate of hospitalizations reduced from 1,028 to 630. Rate of out-patient visits reduced from 20,404 to 16,320.

Among 45–64 year olds, the mortality due to external causes reduced from 63.7 to 50.0. Rate of hospitalizations reduced from 1,071 to 722. Rate of out-patient visits reduced from 18,713 to 11,998.

Among those 65 years or older, the mortality due to external causes reduced from 135.3 to 117.3. Rate of hospitalizations increased from 1,620 to 2,094. Rate of out-patient visits increased from 15,332 to 15,537.

Conclusions Among 0–14 olds, the mortality due to external causes decreased significantly from 1984 to 2011, but the out-patient visit rate remained almost the same.

Among those 65 or older, the mortality due to external causes decreased from 1984 to 2011, but rate of hospitalizations and out-patient visits increased.