Not to take anything away from the meta-analysis and the important points in the blog post, but there's a glaring error in the abstract: "the weighted average effect sizes were as follows: social isolation odds ratio (OR) = 1.29, loneliness OR = 1.26, and living alone OR = 1.32, corresponding to an average of 29%, 26%, and 32% increased likelihood of mortality, respectively."

The authors mean increased /odds/, not likelihood (probability). WHy does it matter? Well, when your whole paper is a statistical exercise, misusing basic statistical language in the abstract is not a great sign.