Suicide is a tragedy that affects many people worldwide, with approximately 800,000 people deciding to take their own lives each year. The COVID-19 pandemic has also increased the suicide rate.
Yun Hak Kim and his colleagues at South Korea’s Busan National University investigated whether there incidence of suicide varied geographically. The team found that exposure to sunlight may have an impact on the prevalence of suicide.
As latitude increases, exposure to sunlight decreases, which can lead to a decrease in the binding of the neurotransmitter serotonin in the brain and blood platelets, which can promote mood disorders and depression.
Analyzing 20 studies published between 1982 and 2020, the team found that the prevalence of suicide increased with increasing latitude, with an increase of 0.255 for each additional degree.
In addition, they found that the prevalence of suicide increased with age and peaked in old age. They also observed that, although countries with firearm restrictions and countries without restrictions had similar values of suicide prevalence, suicide by firearm was more frequent in countries without restrictions.