Time trends in suicide rates by domestic gas or car exhaust gas inhalation in Japan, 1968-1994

Suicide methods in South Asia over two decades (2001-2020)

BACKGROUND

Suicide is a global preventable public health problem. About a quarter of all suicides in the world occur in South Asia. As means restriction is an important suicide prevention strategy, gaining knowledge of the common suicide methods and their changing trends in each country and region is crucial.

AIMS

We aimed to assess the suicide methods in South Asian countries over the last two decades.

METHODS

A search was performed in PubMed, PubMed Central, Scopus, and Google Scholar with the search terms. Original articles of quantitative studies, published in the English language, from 2001 to 2020, with full-accessible text, that rank different methods of suicide in eight South Asian countries, were included.

RESULTS

A total of 68 studies were found eligible for review. The Maximum number of studies were found from India (n = 38), followed by Bangladesh (n = 12), Pakistan (n = 9), Sri Lanka (n = 6), and Nepal (n = 3). Hanging (n = 40, 55.8%) and poisoning (n = 24, 35.3%) were the two most common suicide methods reported, in that order. Hanging followed by poisoning were the commonest suicide methods in Bangladesh, India, and Pakistan while in Sri Lanka, poisoning was the preferred method to hanging. There is a decline in suicide by poisoning and an increase in suicide by hanging in Sri Lanka, Bangladesh, and India. Although hanging is still the commonest method in Pakistan, the use of firearms is growing in recent years (2011-2020).

CONCLUSIONS

There is a steady decline in the incidence of suicides by poisoning following pesticide regulations in South Asian countries. However, there is heterogeneity of study methods, probable under-reporting of suicide, and lack of robust suicide data.

Prehospital characteristics, incidence trends, and outcome of emergency self-inflicted injury patients with gas substances: a population-based descriptive study in Osaka, Japan

AIM

Little is known about the detailed characteristics of patients using gas substances for self-inflicted injury in prehospital settings. The aim of this study was to investigate the characteristics, incidence trends, and outcomes of patients who used gas substances for self-inflicted injury in Osaka City, Japan, using ambulance records.

METHODS

This was a retrospective observational study that used data from 2009 to 2015. We extracted details from ambulance records of self-inflicted injury patients who used gas substances. The annual incidence of self-inflicted injury by gas substance and age group and Poisson regression models were applied for calculating the annual incidence trend by type of gas substance. The main outcome was confirmed death at the scene, and we also calculated the crude odds ratios and 95% confidence intervals for each gas substance.

RESULTS

During the study period, there were 324 self-inflicted injury patients who used gas substances. The most commonly used gases were carbon monoxide (CO) (54.9%), followed by hydrogen sulfide (12.7%), helium (6.5%). The incidence of CO and hydrogen sulfide have subsequently decreased (P for trend = 0.023 and <0.001, respectively); however, the incidence of helium did not change during the study period (P for trend = 0.586). The mortality rate was highest in patients who used helium (66.7% [14/21]) and the crude odds ratio of helium was 3.857 (95% confidence interval, 1.267-11.745; P = 0.017) compared with hydrogen sulfide.

CONCLUSION

This study revealed that the incidence of self-inflicted injury with helium did not change and its proportion of death at the scene was high in Osaka City.

Trends in Suicide Mortality by Method from 1979 to 2016 in Japan

Suicide is a major public health concern in Japan. This study aimed to characterize the trends in suicide mortality in Japan by method since 1979. Using data from the Japan vital registration system, we calculated age-standardized rates of suicide mortality separately by sex and method. We conducted a log-linear regression of suicide mortality rates separately by sex, and linear regression analysis of the proportion of deaths due to hanging, including a test for change in level and trend in 1998. While crude suicide rates were static over the time period, age-adjusted rates declined. The significant increase in suicide mortality in 1998 was primarily driven by large changes in the rate of hanging, with suicide deaths after 1998 having 36.7% higher odds of being due to hanging for men (95% CI: 16.3–60.8%), and 21.9% higher odds of being due to hanging for women (95% CI: 9.2–35.9%). Hanging has become an increasingly important method for committing suicide over the past 40 years, and although suicide rates have been declining continuously over this time, more effort is needed to prevent hanging and address the potential cultural drivers of suicide if the rate is to continue to decline in the future.