Suicide rates across income levels: Retrospective cohort data on 1 million participants collected between 2003 and 2013 in South Korea.
BACKGROUND
The relation of income and socioeconomic status with suicide rates remains unclear. Most previous studies have focused on the relationship between suicide rates and macroeconomic factors (e.g., economic growth rate). Therefore, we aimed to identify the relationship between individuals' socioeconomic position and suicide risk.


METHODS
We analyzed suicide mortality rates across socioeconomic positions to identify potential trends using observational data on suicide mortality collected between January 2003 and December 2013 from 1,025,340 national health insurance enrollees. We followed the subjects for 123.5 months on average. Socioeconomic position was estimated using insurance premium levels. To examine the hazard ratios of suicide mortality in various socioeconomic positions, we used Cox proportional hazard models.


RESULTS
We found that the hazard ratios of suicide showed an increasing trend as socioeconomic position decreased. After adjusting for gender, age, geographic location, and disability level, Medicaid recipients had the highest suicide hazard ratio (2.28; 95% CI, 1.87-2.77). Among the Medicaid recipients, men had higher hazard ratios than women (2.79; 95% CI, 2.17-3.59 vs. 1.71; 95% CI, 1.25-2.34). Hazard ratios also varied across age groups. The highest hazard ratio was found in the 40-59-year-old group (3.19; 95% CI, 2.31-4.43), whereas the lowest ratio was found in those 60 years and older (1.44; 95% CI, 1.09-1.87).


CONCLUSIONS
Our results illuminate the relationship between socioeconomic position and suicide rates and can be used to design and implement future policies on suicide prevention.
Department of Mental Health Research, Seoul National Hospital, Seoul, South Korea; Department of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul, South Korea.
Sang-Uk
SU
Lee
Department of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul, South Korea.
In-Hwan
IH
Oh
Department of Psychiatry, Depression Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea; Department of Health Sciences & Technology, Samsung Advanced Institute for Health Sciences & Technology, Seoul, South Korea; Department of Clinical Research Design and Evaluation, Samsung Advanced Institute for Health Sciences & Technology, Seoul, South Korea; Department of Medical Device Management and Research, Samsung Advanced Institute for Health Sciences & Technology, Seoul, South Korea; Depression Clinical and Research Program, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Hong Jin
HJ
Jeon
Department of Psychiatry, Hanyang University College of Medicine, Seoul, South Korea. Electronic address: swroh@hanyang.ac.kr.
Sungwon
S
Roh
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007182:Income / Q000706:statistics & numerical data*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D012923:Social Class; D013405:Suicide / Q000706:statistics & numerical data*; D055815:Young Adult
Income; Socioeconomic position; Suicide rate