November 10, 2023BMC Medicine49 citationsOpen Access
Social connection and mortality in UK Biobank: a prospective cohort analysis
Key Result
Combined functional and structural isolation increased cardiovascular disease mortality risk (HR 1.63) compared to no isolation in UK Biobank participants.
Study Design
Type
Cohort (n=458,146)
Multicenter
Yes
Structured PICO
Does social isolation (functional and structural components) increase all-cause and cardiovascular mortality in the general adult population?
P
Population
458,146 participants from the UK Biobank cohort, mean age 56.5 years, 54.7% female, 95.5% white ethnicity.
I
Intervention
Functional and structural components of social isolation (frequency of ability to confide, feeling lonely, friends/family visits, weekly group activities, living alone)
C
Comparator
Higher levels of social connection (e.g., daily friends/family visits, not living alone, not feeling lonely)
O
Outcome
All-cause mortality and cardiovascular disease (CVD) mortality at median 12.6 years follow-uphard clinical
Both functional and structural components of social isolation are independently and synergistically associated with increased all-cause and cardiovascular mortality.
Main Result
Effect estimate: HR 1.63 (95% CI 1.51-1.76)
Limitations
- Potential for reverse causality where poor health impairs ability to maintain relationships
- Exclusion of participants with missing data who generally had worse health profiles
- Reliance on self-reported measures of social connection
Abstract
BACKGROUND: Components of social connection are associated with mortality, but research examining their independent and combined effects in the same dataset is lacking. This study aimed to examine the independent and combined associations between functional and structural components of social connection and mortality. METHODS: Analysis of 458,146 participants with full data from the UK Biobank cohort linked to mortality registers. Social connection was assessed using two functional (frequency of ability to confide in someone close and often feeling lonely) and three structural (frequency of friends/family visits, weekly group activities, and living alone) component measures. Cox proportional hazard models were used to examine the associations with all-cause and cardiovascular disease (CVD) mortality. RESULTS: Over a median of 12.6 years (IQR 11.9-13.3) follow-up, 33,135 (7.2%) participants died, including 5112 (1.1%) CVD deaths. All social connection measures were independently associated with both outcomes. Friends/family visit frequencies < monthly were associated with a higher risk of mortality indicating a threshold effect. There were interactions between living alone and friends/family visits and between living alone and weekly group activity. For example, compared with daily friends/family visits-not living alone, there was higher all-cause mortality for daily visits-living alone (HR 1.19 95% CI 1.12-1.26), for never having visits-not living alone (1.33 1.22-1.46), and for never having visits-living alone (1.77 1.61-1.95). Never having friends/family visits whilst living alone potentially counteracted benefits from other components as mortality risks were highest for those reporting both never having visits and living alone regardless of weekly group activity or functional components. When all measures were combined into overall functional and structural components, there was an interaction between components: compared with participants defined as not isolated by both components, those considered isolated by both components had higher CVD mortality (HR 1.63 1.51-1.76) than each component alone (functional isolation 1.17 1.06-1.29; structural isolation 1.27 1.18-1.36). CONCLUSIONS: This work suggests (1) a potential threshold effect for friends/family visits, (2) that those who live alone with additional concurrent markers of structural isolation may represent a high-risk population, (3) that beneficial associations for some types of social connection might not be felt when other types of social connection are absent, and (4) considering both functional and structural components of social connection may help to identify the most isolated in society.