Koreans who are obese or overweight are less likely to kill themselves than those who are of average weight or under, a study by local endocrinologists showed Monday.
Researchers from the Department of Endocrinology and Metabolism at the Catholic Univ. of Korea Seoul St. Mary's Hospital analyzed the data of 4.04 million adults from 2009 to Dec. 31 of 2021, using the database of the National Health Insurance Service.
They analyzed the subjects based on body mass index, record of mental and chronic diseases, and other factors such as age, gender and physical conditions.
The study showed the risk of suicide among people with BMI of 23 to 25 -- calculated as kilograms per meter of height squared -- was 21 percent lower than it was among people with a BMI of 18.5-22.9. Korean standards class 23-25 as overweight.
People with higher BMIs were even less likely to take their own lives. Suicide risk among people with class one obesity -- BMI of 25-29.9 -- were 24 percent lower than for people in the 18.5-22.9 BMI range, and the suicide risk among those with class 2 obesity -- a BMI of 30 and above -- was 29 percent lower.
A BMI between 18.5 and 22.9 is considered within healthy range in Korea. This is different from the standards by the World Health Organization, which categorizes from 18.5 to 24.9 as healthy weight, classifies 25 to 29.9 as overweight, and 30 or higher as obese.
Underweight individuals -- with a BMI of less than 18.5 -- showed increased risk of suicide, at 44 percent higher than for those considered to be in the healthy range.
The study noted that the relationship between weight and suicide risk was "consistent regardless of the presence of a major depressive disorder, or the type of living arrangements of the participants."
Among the possible factors behind this phenomenon is the obesity-induced leptin resistance, which the researchers noted that may have contributed to decreased impulsivity. The hormone produced by fat tissues signals the brain to regulate hunger and energy balance, and the researchers noted that obesity can lead to the brain becoming less responsive to leptin.
Resistance to leptin can also lead to overeating and gaining weight.
"Our data suggests the importance of physiological factors associated with body mass in understanding suicidal death risk. Furthermore, these data provide valuable insights to where the public health resources should be invested to reduce suicidal death rates," the research concluded.
It noted, however, that the relationship between the BMI and suicidal death risk is complex, and warrants further investigation.
The study was published in the January edition of the BMC Psychiatry.
South Korea has among the highest suicide rates in the world, with 24.1 suicides per 100,000 inhabitants in 2020 to mark the highest figure among members of the Organization for Economic Cooperation and Development.
A total of 13,195 people in Korea died by suicide in 2020, according to Statistics Korea, but number has risen since then. Suicide deaths in 2021 increased to 13,352, decreased to 12,906 in the following year, but went back up to 13,987 in 2023 -- which marks 27.3 suicides per 100,000.
The provisional figures by the state-run Korea Foundation for Suicide Prevention projected the number of suicides for 2024 to be upward of the 15,906 in 2011, making it the highest number on record.
