Two studies published in the Archives of Internal Medicine looked at the association of living alone and loneliness with increased mortality.
The first study found that there is an association between living alone and increased risk of mortality and cardiovascular death in middle-aged outpatients with or at risk of atherothrombosis. The second study revealed that in a population of older patients, loneliness was a predictor of functional decline and death
Since it is thought that "social isolation or an absence of real or perceived social support may be associated with poor health consequences, including cardiovascular disease," the first study investigated whether social isolation is associated with increased cardiovascular risk and mortality in international populations of outpatients with or at risk of atherothrombosis. The authors note that no previous study has investigated the "risk associated with social isolation" in outpatient groups with varying risk factors on an international level.
The study looked at 44,573 participants in the REACH Registry, of those 8,594 were living alone. The authors found that "living alone was associated with higher four-year mortality (14 percent vs. 11.1 percent) and cardiovascular death (8.6 percent vs. 6.8 percent log-rank P<.01 for both comparisons). However, there was significant effect modification by age. Specifically, among younger participants, living alone compared with those living with others was associated with higher mortality."
Based on these results, "living alone at a younger age may be a marker of a stressful psychosocial situation, such as job strain or isolation, with adverse neurohormonal effects on the CV system, that may have more impact in youth to influence health behavior and wellness."
The authors conclude that "younger patients living alone after an atherothrombotic ischemic event may be an additional risk group on which to focus efforts to improve prognosis."
The second study looked at the relationship between loneliness, functional decline and death in those who are older than 60 years in the U.S. According to the authors, “the hypothesis that loneliness may be a risk factor for adverse health outcomes in older persons is supported by previous studies that show that other forms of psychosocial distress lead to adverse health outcomes." This study aimed to examine the impact of loneliness on mortality and several measures of worsening disability.
The study was a longitudinal cohort study and used the 2002 Health and Retirement Study (HRS), a national, population-based study of community living older adults, to look at 1,604 participants in the psychosocial module.
The study revealed that among the elderly participants, 43 percent reported feeling lonely and that lonely persons were more likely "to experience decline in activities of daily living; develop difficulties with upper extremity tasks; experience decline in morbidity; or experience difficulty in climbing." Furthermore, the authors state, "Loneliness was also associated with an increased risk of death."
The authors note that their study "may have important public health implications, since nearly one in three subjects reported loneliness, and the association between loneliness and sociability and death was strong." The authors suggest that strategies of mitigating loneliness, such as diverse living arrangements and telephone support, could be explored.
In a commentary, Emily Bucholz, MPH, and Harlan Krumholz, MD, SM, FACC, explain how social support is hard to define and measure. They emphasize that "scientists examining social support should build on studies such as [these] and be challenged to investigate mechanisms as well as practical interventions that can be used to address the social factors that undermine health."