Gopinath B, Rochtchina E, Anstey KJ, Mitchell P. Living Alone and Risk of Mortality in Older, Community-Dwelling Adults. JAMA Intern Med. 2013;173(4):320-321. doi:10.1001/jamainternmed.2013.1597
Author Affiliations: Centre for Vision Research, Department of Ophthalmology, Westmead Millennium Institute, University of Sydney, Sydney, Australia (Drs Gopinath and Mitchell and Ms Rochtchina); and Ageing Research Unit, Centre for Mental Health Research, Australian National University, Canberra (Dr Anstey).
Two recent articles in this journal1,2 examined the impact of living alone and loneliness on mortality risk. Perissinotto et al2 showed that in persons aged 60 years or older, loneliness was associated with 45% increased risk of total mortality. Udell et al1 showed that among outpatients 45 years or older from the REduction of Atherothrombosis for Continued Health (REACH) study, living alone was associated with increased risk of cardiovascular disease (CVD) and total mortality, particularly among younger participants. However, both studies did not adjust for self-reported mental and physical health, which is significantly associated with social support and mortality.3,4 We investigated the association between living alone and risk of all-cause and CVD mortality among older Australians, independent of self-perceived health status and other confounders.
The Blue Mountains Eye Study (BMES) is a population-based cohort study with methods previously reported.5 During 1992 to 1994, 3654 participants 49 years or older were examined (82.4% participation rate). At the 5-year follow-up examination, 2335 surviving participants (75.1% of survivors; 543 had died) and an additional 1174 individuals were examined. This provided a sample of 3508 individuals who had self-reported health status information. Of these, 22 participants had missing mortality and living alone data and so were excluded from analyses, leaving 3486 participants.
To identify and confirm persons who died after the baseline examination, participants were cross-matched with Australian National Death Index data6 for deaths until December 31, 2007 (10-year follow-up). Total and cause-specific mortality were assessed using the International Classification of Diseases, Ninth Revision (ICD-9) and International Statistical Classification of Diseases, 10th Revision (ICD-10) definitions, as described in our previous study.6 Self-reported health status was assessed using the 36-Item Short-Form Survey (SF-36), which produces 8 subscale scores representing dimensions of health and well-being. Participants were asked who lived with them; if they responded that they lived with nobody or with pets only, they were classified as living alone. Covariates adjusted for in mortality analyses were age, sex, educational status (tertiary qualified or not), current smoking, body mass index, walking disability, prior diagnosis of heart disease, angina, heart attack, diabetes mellitus, cancer, poor self-rated health, and SF-36 mental and physical component summary scores.
During the 10-year follow-up period, a total of 739 participants (21.2%) died. After multivariate adjustment, living alone was not associated with total mortality in the overall cohort (Table). There was a nonsignificant effect modification by age (P = .50 for interaction). However, given that there is a psychosocially plausible reasoning for an age-specific effect of living alone on mortality risk1; analyses were stratified by age-group. Among participants younger than 75 years, living alone was associated with a 36% increased risk of all-cause mortality (15.0% vs 11.4%; multivariate-adjusted hazard ratio, 1.36 [95% CI, 1.04-1.79]). In those 75 years or older, living alone was not associated with both total mortality (Table) and CVD mortality (P = .48).
In the BMES, living alone was a significant predictor of all-cause mortality among those younger than 75 years, independent of self-perceived health status and socioeconomic and medical covariates. This observation is similar to that of the REACH study, which found a more marked association between living alone and mortality in those 80 years or younger.1 This is not surprising given that living alone is both a measure of normative behavior and functional independence in the very elderly.1 Unlike the REACH study, we could not confirm a significant association with CVD mortality, and this is likely due to ours being a population-based sample, whereas REACH is a sample of outpatients with preexisting CVD risk.1 Nevertheless, our findings concur with those of Perissinotto et al2 and Udell et al1 that lack of social support, whether it be measured objectively (living arrangements) or subjectively (feelings of loneliness), has a negative impact on health and would be worth addressing in future intervention studies.
Correspondence: Dr Mitchell, Centre for Vision Research, Department of Ophthalmology, University of Sydney, Westmead Hospital, Hawkesbury Road, Westmead, NSW 2145, Australia (firstname.lastname@example.org).
Published Online: January 14, 2013. doi:10.1001/jamainternmed.2013.1597
Author Contributions:Study concept and design: Gopinath and Mitchell. Acquisition of data: Mitchell. Analysis and interpretation of data: Gopinath, Rochtchina, and Anstey. Drafting of the manuscript: Gopinath. Critical revision of the manuscript for important intellectual content: Rochtchina, Anstey, and Mitchell. Statistical analysis: Rochtchina. Obtained funding: Mitchell. Administrative, technical, and material support: Anstey. Study supervision: Gopinath, and Mitchell.
Conflict of Interest Disclosures: None reported.