Demographic and epidemiological decomposition analysis of global changes in suicide rates and numbers over the period 1990–2019

Suicide presents an ongoing public health challenge internationally. Nearly 800 000 people around the world lose their life to suicide every year, and many more attempt suicide.A decomposition analysis was performed using global suicide mortality and population data from the Global Burden of Disease Study 2019.Despite a significant decrease in age-specific suicide rate between 1990 and 2019 (-4.01; from 13.8% to 9.8% per 100 000), the overall numbers of suicide deaths increased by 19 897 (from 738 799 to 758 696) in the same time period. The reductions in age-specific suicide rates (-6.09; 152%) contributed to the overall reductions in suicide rates; however, this was offset by overtime changes in population age structure (2.08; -52%). The increase in suicide numbers was partly attributable to population growth (300 942; 1512.5%) and population age structure (189 512; 952.4%), which was attenuated by the significant reduction in overall suicide rates (-470 556; 2364.9%). The combined effect of these factors varied across the World Bank income level regions. For example, in the upper-middle-income level region, the effect of the reduction in age-specific suicide rates (-289 731; -1456.1%) exceeded the effect of population age structure (124 577; 626.1%) and population growth (83 855; 421.4%), resulting in its substantial decline in total suicide deaths (-81 298; -408.6%). However, in lower-middle income region, there was a notable increase in suicide death (72 550; 364.6%), which was related to the net gain of the reduction in age-specific suicide rates (-115 577; -580.9%) and negated by the increase in the number of suicide deaths due to population growth (152 093; 764.4%) and population age structure (36 034; 181.1%).More support and resources should be deployed for suicide prevention to the low-income and middle-income regions in order to achieve the reduction goal. Moreover, suicide prevention among older adults is increasingly critical given the world's rapidly ageing populations in all income level regions.