Social relationships and mortality risk: a meta-analytic review

148 studies, 308,000 people, and the effect size that turned loneliness into a public health problem.

Holt-Lunstad, Smith & Layton (2010). PLoS Medicine 7(7), e1000316. Read it.

Primary reading — read it before the lecture that sets it.

People with stronger social relationships had a 50% greater likelihood of survival across the follow-up periods. The comparisons that made the paper famous — that the effect is comparable to quitting smoking, and larger than obesity or physical inactivity — are in the discussion, and they are the reason health ministries started using the word loneliness.

Week 11 is what it costs. Read this one properly, including the limitations: these are observational studies, the measures of “social relationship” are wildly heterogeneous, and the causal arrow is not settled by a meta-analysis. You should finish the week able to state the finding accurately and able to say what it does not establish. Both halves get marked.