Reading: Holt-Lundstad (2021) - The Major Health Implications for Social Connection

Question 1

What is Holt-Lundstad 2021

Answer 1

• Is a review to show the cumulative evidence for the links between mortality and social connection as well as morbidity and social connection and touches on some potential mechanisms for this

Question 2

Why are humans social creatures

Answer 2

• Social connection has adaptive benefits for humans and animals eg. safety and efficiency of effort, protecition etc
  o Research has shown humans are designed to be social, with evidence suggesting that humans use more metabolic reasources when presented with a threat alone than when with others

Question 3

What is social connection and it’s 3 measures

Answer 3

 There are three broad categories of measurement approaches when it comes to social relationships and physical outcomes
* 1. Structural aspects of social life
o Size of network
o Number of social roles
o Whether someone lives alone etc
* 2. Functional aspects of social life
o Received or perceived availability of social support, resources and aid
* 3. Quality
o Affective valence
o Satisfaction strain
o Adjustment
 Whilst there is some overlap among these components these are not highly correlated
 The terms social connection (or social disconnection) are umbrella terms to encompass the structure, function and quality of social relationships
* Social connectedness can be conceptualised as a continuum such that high levels on the components of social connection are associated with protection and low levels with risk

Question 4

o Health Consequences; Mortality

Answer 4

 Social disconnection is linked to earlier death
 Emil Durkheim was one of the first to acknowledge this seeing that socially isolated people were more likely to commit suicide
 Holt-Lundstad assessed 148 studies and found that social connection increases survival odds by 50%
* A subsequent meta-analysis focussed on the effect of social disconnection and revealed that loneliness si associated with increased risk of premature deal by 26% and loneliness offered a 29% increased risk of early death whilst living alone was 32%.
o Subjective (loneliness) and objective (social isolation and living alone) are significant predictors of mortality.
* These findings are independent of age, health heatus, gender, country of origin and cause of death etc

Question 5

o Health consequences; Morbidity

Answer 5

 The growing body of research has found that social connection extends life span and disconnection is associated with several physical health outcomes like type 2 diabetes, cold virus susceptibility, upper respiratory illness and pulmonary function
 The strongest evidence is that social isolation is linked to cardiovascular outcomes
* A meta-analysis of 16 longitudenal studies found that poor social relationships was associated with a 29% increase in the risk of incident coronary heart disease and a 32% increase in risk of stroke

Question 6

o Mechanism

Answer 6

 There are multiple mechanisms that plausible could explain how social connection impacts physical health outcomes.
* Eg. morbidity and mortality outcomes could be driven by psychological factors – eg. perceived stress and depression. Behavioural factors such as sleep, phsyical activity and smoking. Or biological factors like inflammation
o These are not independent pathways but likely interconnected
* Eg. perception of social threat like loneliness may elevate activity of the sympathetic nervous system and the HPA axis. This can cause glucocorticoid resistance and leukocyte development (which I think is inflammation). Social experience can also alter human genome wide activity and impair glucocorticoid response to increase pro-inflammatory transcription. And chronic inflammation has been implicated in phsyical mental and cognitive health – which suggests a common pathway by which social disconnection may influence multiple health outcomes.

Question 7

• Directionality

Answer 7

o How do we know social isolation causes poor health and it’s not that poor health causes isolation?
o However, evidence suggests it’s a directional effect of social disconnection causes greater mortality

Question 8

• Causality

Answer 8

o The Bradford Hill guidelines are used to draw causal inference in epidemiological research using 9 criteria.
o The relationship between social connection and mortality aligns with this criteria suggesting this may be a causal relationship

Question 9

 Gaps and Challenges; measurement

Answer 9

• Measurement
  o Despite the evidence that social connection is a multi-factorial risk factor, there is no single assessment tool that is comprehensive.
  o Therefore few studies assess multiple components of social connection in the same sample to examine synergistic effects

Question 10

Gaps and Challenges; Underrepresented Samples

Answer 10

o Mortality data is primarily based on middle age and older adult samples, given that mortality and morbidity are more likely to occur in these age groups than in younger individuals – but younger samples need to be studies to understand the developmental trajectory

Question 11

 Intervention to Reduce Risk

Answer 11

• Despite strong evidence of the healthy consequences of social disconnection there’s little evidence on how to intervene

Question 12

 Social Technology

Answer 12

• Much research predates when technology became so widespread. Although the body of literature that considers this is growing it’s mostly cross-sectional so we need longitudenal assessment into this

Question 13

 Implications for Medical Practise and Public Health

Answer 13

• Decades of cumulative evidence points to potential long-term health risks if steps aren’t taken to mitigate the effects of social disconnection. Given the significant prevalence of social disconnection within the population, social connection should be prioritised in public health
• NASEM has presented 5 goals ; Develop a more robust evidence base, translate current research in to healthcare practises, improve awareness, strengthen ongoing education and training and strengthen ties between the healthcare system and community based networks and resources.