Mortality Risk Following a Household Suicide.

Importance: The broader mortality risks faced by household members following a suicide remain poorly understood, particularly in low- and middle-income countries. Objectives: To estimate the risk of all-cause and cause-specific mortality among surviving household members after a suicide within the household and to identify individual and contextual factors associated with mortality risk using data from a national population-based cohort in Brazil. Design, setting, and participants: This nationwide cohort study used data from the 100 Million Brazilian Cohort linked to the Mortality Information System (SIM) (2001-2018). All individuals who lived in a household with a suicide index case were considered exposed. Data were analyzed from March 2023 to September 2025. Main Outcomes and Measures: All-cause mortality, cause-specific mortality, and suicide. Outcomes were derived from the national mortality tracking system. The adjusted hazard ratio of all-cause and specific-cause mortality was calculated using a multivariate, time-varying Cox regression. The risk factors associated with increased mortality, including characteristics of the index case, surviving household members, household conditions, and the timing since the suicide event were also analyzed. Results: The cohort included 101 million individuals, of which there were 47 982 suicide index cases identified. Household members exposed to a suicide (11 070 [7%] Black, 82 407 [53%] Parda, and 57 726 [37%] White) had a 32% higher risk of all-cause mortality (adjusted hazard ratio [aHR], 1.32; 95% CI, 1.28-1.36). The risk of suicide among exposed individuals was more than 4 times higher (aHR, 4.42; 95% CI, 3.86-5.07), with 101 of these deaths (44%) occurring within 2 years of the index suicide case. The population attributable fraction for suicide was 77%. Elevated risks were also observed for other external causes (eg, assault and falls) and nonexternal causes (eg, neoplasms and circulatory and respiratory diseases). Mortality risk was highest when the index case was female and younger, among male survivors, and individuals aged 25 to 59 years. Better household conditions were associated with lower risks of both suicide and all-cause mortality. Conclusions and Relevance: Exposure to suicide within the household was associated with a substantial increase in both suicide-specific and all-cause mortality among surviving household members, particularly in the immediate aftermath. These findings underscore the urgent need to incorporate targeted postvention strategies into comprehensive suicide prevention efforts.