Method-specific suicide mortality rates among older adults in 47 countries and territories, 1996-2021, with projections to 2050: a global time series and modelling study.

BACKGROUND

Suicide rates are highest among older adults, yet comprehensive global studies are limited. This study aimed to estimate suicide mortality rates among older adults aged 65 years and older across 47 countries and territories from 1996 to 2021, including analyses by suicide method, project future rates to 2050, and identify associated factors.

METHODS

The study adhered to the Guidelines for Accurate and Transparent Health Estimates Reporting. We extracted suicide mortality data of older adults (≥65 years) across 47 countries and territories from the WHO Mortality Database for the period 1996-2021. We first estimated suicide mortality rates using a locally estimated scatterplot smoothing curve from 1996 to 2021, conducting subanalyses by sex, age subgroup, and suicide method. We then estimated future projections of suicide mortality rates to 2050 via Bayesian age-period-cohort (BAPC) modelling. We also performed a decomposition analysis using the Das Gupta method to identify factors contributing to changes in suicide death numbers between 1996 and 2021. Finally, we examined associations between suicide mortality rates in 2021 or the most recent available year and country-level indicators (poverty rate, disability-adjusted life-year [DALY] rates for alcohol use disorders and mental disorders, civilian firearm ownership, and pesticide use per cropland).

FINDINGS

A total of 687 443 older adults who died by suicide (75·2% men, 24·8% women) were included in the analysis. The suicide mortality rate among adults aged 65 years and older was 15·99 deaths per 100 000 (95% CI 14·19-17·80) in 2021, significantly higher than the all-age suicide mortality rate of 10·87 deaths per 100 000 (9·86-11·87) in 2021 (p<0·0001). Firearms were more frequently used by older adults who died by suicide, compared with the total population (14·91% vs 9·88%, respectively; p<0·0001). The firearm-related suicide mortality rate among older adults was 2·44 per 100 000 (95% CI 2·00-2·89) in 2021, approximately twice that of individuals of all ages (1·09 per 100 000; 0·88-1·31; p<0·0001). There was an overall decline in suicide mortality rates among older adults from 1996 to 2021 (average annual percentage change [AAPC] -1·51 per 100 000; 95% CI -1·52 to -1·50), which was more pronounced among women (AAPC -2·24 per 100 000; -2·28 to -2·21) than in men (AAPC -1·45 per 100 000; -1·48 to -1·42; p<0·0001). Older age subgroups had smaller AAPCs (p<0·0001 for comparisons across all age subgroups). Notably, among adults aged 80 years and older, the suicide mortality rate by firearm showed no statistically significant change between 1996 and 2021. BAPC model projections suggest a slowing in the decline of suicide mortality rates among older adults to 2050. Decomposition analysis indicated that compared with 1996, the total number of suicides in 2021 increased by 7781 deaths primarily due to population growth. Suicide mortality rates among older adults generally increased with higher poverty rates, DALY rates for mental disorders and alcohol use disorders, as well as Human Development Index. Additionally, increasing civilian firearm ownership rates and pesticide use per cropland area were associated with higher suicide mortality rates among older adults who died by firearm and other poisoning, respectively.

INTERPRETATION

Although suicide mortality rates among older adults have declined, the slowing pace of the decline and the rapid ageing of the global population make it an increasing public health concern. Associations between the availability of means such as firearms and pesticides and method-specific suicide rates support existing evidence that restricting access to highly lethal methods can reduce suicide mortality. Variation in suicide methods by sex, age, and country, such as the higher use of firearms among older adults and more frequent use of drug or other poisoning among older women, can inform tailored risk assessments and prevention strategies.

FUNDING

Wellcome Trust and National Research Foundation of Korea.