Global, regional and national trends in suicide mortality rates across 102 countries from 1990 to 2021 with projections up to 2050

Abstract

Global trends and future projections of suicide mortality are crucial to providing policy decision-makers with insights into estimating the global and future burden of suicide; however, they require techniques accounting for the effects of age, period and cohort on trends in suicide mortality and considering various factors such as population growth and aging. Therefore, we aimed to estimate the global trends in suicide mortality rates from 1990 to 2021 and the future projection of suicide deaths until 2050 across 102 countries. Global trends were calculated using a locally weighted scatter-plot smoother (LOESS) curve, and the association between the rates and socioeconomic and geographical indicators was investigated. The study also projected future suicide mortality rates up to 2050 using the Bayesian age–period–cohort model. In addition, a decomposition analysis was performed to identify the variations in suicide deaths, specifically examining factors such as population growth, aging and epidemiological changes. Of the 102 countries included in the analysis of suicide mortality, 54 were high-income countries (HICs) and 48 were low- and middle-income countries (LMICs). The LOESS estimate of the global suicide mortality rate decreased from 10.33 (95% confidence interval, 9.67–10.99) deaths per 100,000 people in 1990 to 7.24 (6.58–7.90) deaths per 100,000 people in 2021. Notably, overall global suicide mortality rates were higher among males compared with females, with males showing a decline from 16.41 (15.23–17.58) in 1990 to 11.51 (10.33–12.68) in 2021, and females from 4.65 (4.41–4.89) in 1990 to 3.22 (2.98–3.46) in 2021. In addition, HICs also had higher suicide mortality rates, from 12.68 (11.96–13.40) in 1990 to 8.61 (7.89–9.33) in 2021, compared with LMICs, which showed 7.88 (6.93–8.84) in 1990 and 5.73 (4.77–6.69) in 2021. We also identified an association between the age-standardized suicide rates and several parameters, including the Human Development Index (β, 24.250; P = 0.001), Sociodemographic Index (β, 0.091; P < 0.001), reverse Gender Gap Index (β, −39.913; P = 0.002), Gender Inequality Index (β, 13.229; P = 0.016) and latitude (β, 23.732; P < 0.001). The future predicted number of global suicide deaths up to 2050 would slightly decrease from 8.60 (95% credible interval, 8.40–8.83) deaths in 2021 to 8.42 (6.60–10.61) in 2030, 7.39 (4.25–13.17) in 2040 and 6.49 (2.19–17.57) in 2050. Although population growth and aging had contributed to an increase in the number of deaths, the overall count in 2021 had decreased compared with 1990, primarily due to the decline in the age-standardized suicide mortality rates. A global trend for a decrease in suicide mortality rate was observed from 1990 to 2021. Reflecting the overall decline, future suicide deaths are forecasted to decrease up to 2050 at the global level, with certain groups and countries remaining more vulnerable to suicide deaths. Therefore, these findings suggest the need for more effective strategies and policies to reduce suicide mortality. This study estimates global suicide mortality trends from 1990 to 2021 and projects future rates until 2050 using a locally weighted scatter-plot smoother and Bayesian age–period–cohort models, revealing substantial declines and highlighting socioeconomic factors influencing variations across high- and low-income countries.