Researchers investigated temporal variations in suicide risk across multiple countries, revealing crucial insights for improved prevention strategies

Suicide, a leading global health concern, ranks fourth among young people. Although many studies have reported temporal variations in suicide risk, most are limited to Western countries. Addressing this gap, researchers from Korea and Japan in collaboration with other countries conducted a multi-country multi-city study to investigate variations in suicide risk based on the day of the week and national holidays, revealing key insights that could help form effective and targeted suicide prevention action plans.

Image title: Suicide risk variation based on days of the week and national holidays

Image caption: The study reveals that Mondays and New Year’s Day have the highest suicide risk across multiple countries. These findings can guide more effective and targeted action plans for preventing suicides.

Image credit: Whanhee Lee from Pusan National University

License type: Original Content

Usage restrictions: Cannot be reused without permission

Suicide is a pressing global public health concern, claiming around 700,000 lives in 2019 according to the World Health Organization, making it the fourth leading cause of death among young people aged between 15 and 29 years. Understanding the mechanisms of suicide is, therefore, essential for creating effective prevention strategies.

Research has shown that suicide rates vary with the time of the year. Several studies have also reported short-term variations based on the day of the week and holidays. The “broken-promise effect theory” has been widely adapted to explain these variations. This theory states that people may postpone suicides in hopes of a new beginning when a cycle ends, such as on weekends or at the end of the year, while they may feel more vulnerable and hopeless at the start of a new cycle, such as on Mondays or New Year’s Day. However, these findings cannot be generalized, as existing studies mainly focus on Western countries.

To address this gap, an international research team consisting of Whanhee Lee (Assistant Professor, the School of Biomedical Convergence Engineering at Pusan National University, South Korea), Cinoo Kang (Doctoral Student, the Graduate School of Public Health, Seoul National University, South Korea), Yoonhee Kim (Associate Professor, Department of Global Environmental Health, The University of Tokyo, Japan), and the Multi-City multi-Country (MCC) Collaborative Research Network investigated short-term variations in suicide risk concerning the days of the week and national holidays across various countries.

“Applying a unified approach to various countries allows us to provide comparable results and better understand how suicide risk changes across different timescales and diverse cultures,” explains Dr. Lee. Their study was published in The BMJ on October 23rd 2024.

The researchers used an advanced statistical technique called standardized two-stage time series analysis to investigate suicide risk patterns. They analyzed data from 740 locations across 26 countries, gathered from the Multi-country Multi-city Collaborative Research Network database. This dataset comprised 1.7 million suicide cases, including daily suicide counts along with daily mean temperature data spanning from January 1971 to December 2019.

The results revealed that suicide risk was highest on Mondays across all countries, though the effect of weekends varied. New Year’s Day was associated with an increase in suicide risk in all countries, while Christmas showed a mixed pattern. Although there was an overall decreasing trend in suicide risk on other national holidays, the risk tended to increase after these holidays in most countries. Notably, the findings also showed that men are more vulnerable to variations related to the day of the week and New Year’s Day compared to women.

Highlighting the importance of this study, Dr. Lee remarks “Our findings provide a better understanding of the temporal variations in suicide, which can lead to better evidence based-suicide theories.”

We hope that this large-scare study can lead to timely interventions, potentially saving countless lives.

Reference

Title of original paper: Association of holidays and the day of the week with suicide risk: multicountry, two stage, time series study

Journal: The BMJ

DOI: https://www.bmj.com/content/387/bmj-2024-077262

About the institute

Pusan National University, located in Busan, South Korea, was founded in 1946 and is now the No. 1 national university of South Korea in research and educational competency. The multi-campus university also has other smaller campuses in Yangsan, Miryang, and Ami. The university prides itself on the principles of truth, freedom, and service, and has approximately 30,000 students, 1200 professors, and 750 faculty members. The university is composed of 14 colleges (schools) and one independent division, with 103 departments in all.

Website: https://www.pusan.ac.kr/eng/Main.do

About the author

Dr. Whanhee Lee is an Assistant Professor at the School of Biomedical Convergence Engineering at Pusan National University. He has a Ph.D. in Public Health (Biostatistics major) from Seoul National University and his main research interests include climate change, air pollution, health disparities, and planetary health. He can be reached at whanhee.lee@pusan.ac.kr.

Lab website: https://www.whanheelee.com/

ORCID id: ORCID id: 0000-0001-5723-9061