Abstract and Introduction
Objectives: To evaluate the association between living alone and suicide and how it varies across sociodemographic characteristics.
Methods: A nationally representative sample of adults from the 2008 American Community Survey (n = 3 310 000) was followed through 2019 for mortality. Cox models estimated hazard ratios of suicide across living arrangements (living alone or with others) at the time of the survey. Total and sociodemographically stratified models compared hazards of suicide of people living alone to people living with others.
Results: Annual suicide rates per 100 000 person-years were 23.0 among adults living alone and 13.2 among adults living with others. The age-, sex-, and race/ethnicity-adjusted hazard ratio of suicide for living alone was 1.75 (95% confidence interval = 1.64, 1.87). Adjusted hazards of suicide associated with living alone varied across sociodemographic groups and were highest for adults with 4-year college degrees and annual incomes greater than $125 000 and lowest for Black individuals.
Conclusions: Living alone is a risk marker for suicide with the strongest associations for adults with the highest levels of income and education. Because these associations were not controlled for psychiatric disorders, they should be interpreted as noncausal. (Am J Public Health. 2022;112(12):1774–1782. https://doi.org/10.2105/AJPH.2022.307080)
Between 1960 and 2021, the percentage of single-person households in the United States increased from 13% to 28%. One-person households also account for more than a quarter of all households in many other high-income countries including France, England, Germany, Canada, Spain, and Japan. In light of the substantial number and rising proportion of adults who live alone, there is interest in understanding whether and to what extent living alone is associated with adverse health outcomes.
Several general population cohort studies have reported that living alone is connected with increased risk of all-cause mortality. In one review, the average increased risk of all-cause mortality for living alone (32%) was similar to the corresponding risks for social isolation (29%) and loneliness (26%). A recent meta-analysis reported that living alone is associated with increased risk of all-cause mortality for individuals aged younger than 65 years and may be more pronounced for males than females. Informed by social and psychological theories linking social isolation to suicide risk, several studies have specifically probed relationships between living alone and risk of suicide. Cohort studies of various high-risk populations including adults following nonfatal suicide attempts, people with disabilities attributable to mental disorders, adults with bipolar disorder, and people hospitalized for depression have all reported significant positive associations between living alone and suicide risk.
In general population samples, living alone has also been reported to be associated with increased risk of suicide. A German population-based cohort study reported that living alone was associated with increased risk of suicide (hazard ratio [HR] = 2.2) similar in magnitude to depressed mood (HR = 2.0). A large Finnish general population cohort study further reported that living alone was associated with increased relative suicide mortality rates for men and women who were working age (30–64 years) and older (≥ 65 years). A recent UK Biobank study, however, found that living alone was associated with an increased risk of suicide in men but not women. A study of older Korean adults that controlled for a wide range of sociodemographic, health, and behavioral health factors similarly found that living alone was related to suicidal ideation for men but not women. Some[14,15] but not all case–control studies have also reported significant associations between living alone and death by suicide.
Because of sample size limitations of previous research, little is known about whether and how the risk of suicide associated with living alone varies across sociodemographic groups beyond the apparent stronger association for men than women. The multiple pathways to living alone, which include relationship dissolution, death of a partner, and decisions not to enter into a cohabitation partnership, contribute to the heterogeneity of this population, and the mental health consequences of living alone could vary across this diverse group.
To better understand the association between living alone and suicide, we followed respondents to the 2008 American Community Survey (ACS) who were either living alone or with others for their risk of death by suicide. Stratified analyses assessed whether living alone varied as a risk marker for suicide across sociodemographic groups. Because the ACS does not include measures of common shared causes of living alone and suicide, such as mental health problems[17,18] and substance misuse,[19,20] we consider these associations as noncausal. Increasing our understanding of the strength and pattern of associations between living alone and suicide might inform risk assessment and future epidemiological research to evaluate the contribution of living alone to suicide risk.
Am J Public Health. 2022;112(12):1774-1782. © 2022 American Public Health Association